摘要:

1270 BURKARD AND TRAVERS: THE ACTION OF CXXVII1.-The Action of Acetylene on the Acetates of Mercury . By EMIL BURKARD, Ph.D., and MORRIS W. TRAVERS, D.Sc. IN the year 1892, the late Dr. R. T. Plimpton published a short account of some compounds which he had obtained by the action of acetylene on mercurous and mercuric acetates in presence of water (Proc., 8, 109). By treating mercurous acetate suspended in water with acetylene, he obt.ained a sitbstance which resembled in its properties the well known acetylides of copper and silver, and the then unknown mercuric acetylide (Plimpton and Travers, Trans., 1894, 64, 264). When treated with hydrochloric acid, it yielded acetylene, it detonated when heated, and with a soIution of iodine, tetriodoethylene and di-iodoacetylene were formed.The compound was not analysed, and the paper contains no suggestion with regard to its formula. When acetylene was passed through a solution of mercuric acetate, P1irr;pton found that a substance of totally different character was formed. The compound to which he assigned the formula 3Rg0,2C2H, did not explode when heated, and when treated with acids it yielded the corresponding mercuric salt and aldehyde. We have taken up the subject a t the point at which i t was left in the year 1892. Action of Acetylene on Mercurous Acetate. Since mercurous acetate is insoluble in water, it is necessary to suspend the finely divided crystals in water and to shake the mixture freely while treating it with acetylene. The reaction takes place rapidly at first, but a s the acetate becomes coated with a layer of the acetplide, the change proceeds more slowly and requires about 30 hours for completion.The reaction must be carried out in absence of daylight, which decomposes the mercurous acetate. The product is always grey in colour, even when the acetylene is perfectly free from sulphuretted hydrogen or phosphoretted hydrogen. The colour is probably due to the presence of a trace of free mercury in insufficient quantity to be of any importance. When the reaction is at an end, the mercury is completely precipi- tated, and by titrating the solution with alkali it is found to contain the whole of the acid originally present in the mercurous salt. The solution has always a strong odour of aldehyde produced by the hydrolysis of the acetylene ; this reaction will be discussed later.TheACETYLENE ON THE ACETATES OF MERCURY. 1271 precipitate, after washing with water and alcohol and drying over sulphuric acid in a desiccator, appears to have a definite composition. The following are the results of analyses : (i) 0,3845 gave 0.4050 HgS. Hg=90*79. (ii) 0.2575 ,, 0.2705 HgS. H g = 90.55. (iii) 0.4287 ,, 014510 HgS. Hg = 90.66. (i) 0.2855 ,, 0.0570 CO, and 0.0150 H,O. C = 5.44; H,O= 5.25. (ii) 0.3405 ,, 0.0715 CO, ,, 0.0180 H,O. C = 5.72; H,O = 5.20. The substance was mixed with n *large quantity of powdered copper oxide before it was introduced into the combustion tube, and a long spiral of silver foil was placed in the tube a t the end nearest t o the absorption apparatus. The silver absorbed the greater part of the mercury vapour, but traces always passed into the sulphuric acid tube, rendering the water determination of no value.If the determinations of the mercury and the carbon are correct, the quantity of water present, determined by difference, is 3.76 per cent. The percentage composition indicates t h a t the compound has the formula C,Hg,,H,O : The combustion was extremely difficult to carry out. O,Hg,. 2C,Hg2, H20. C,Hg2, H20. C,Hg2, 2H20. Hg ............ 94.33 92.50 90.50 86-95 H,O.. .......... - 2.07 4-07 7.83 C ............... 5-66 5.58 5.43 5.22 The substance is then, as Plimpton suggested, closely allied to the acetylides of silver and copper, and t o the mercuric acetylide discovered in 1894. It differs from these compounds in containing one mol.of water to one mol. of the acetylide, whereas the acetylides already known have the general formula SC,M”,H,O. That the water in our compound is present either in combination with the mercury or as water of crystallisation is indicat,ed by the fact that it yields mercurous iodide and tetriodoethylene when treated with a solution of iodine, and acetylene when treated with hydrochloric acid, The water cannot, however, be removed by heating, for at 100’ the compound decomposes, losing, not only water, but carbon, and leaving a residue of indefinite composition. Action of Acetylene on a Xolution of Mercuric Acetate. When acetylene is passed into a solution of mercuric acetate in absence of daylight, a white precipitate is immediately thrown down.The precipitate becomes grey in colour as the reaction proceeds, and the solution smells strongly of aldehyde, produced by the hydrolysis1272 MELLOR AND RUSSELL: THE PREPARATION OF PURE of some of the acetylene in solution. After about two hours, the whole of the mercury is precipitated, the acetic acid remaining in the solu- tion. The precipitate is found to have a somewhat slimy character and is difficult to wash on the filter-paper. This compound, after drying for some days in a vacuum over sul- phuric acid, was analysed, with the following results : 0.4155 gave 0.0940 COP C = 6.16. 0.3100 ,, 0*0676 CO,. C = 5-98. 0.2660 ,, 0.2'703 HgS. Hg = 87.62. 3C2Hg,2Hg0,2H20 requires C = 6.3 ; Hg=87.7 per cent. The compound is not explosive, but on heating strongly it decom- poses, leaving a residue of carbon ; at looo, it loses both water and carbon, leaving a residue of indefinite composition.With a solution of iodine, it yields only mercuric iodide and tetriodoethylene with a little di-iodoacetylene, hence it, is probable that in this compound, as in the case of the compound derived from mercurous acetate, the water is not directly combined with the carbon. The compound may, in fact, be regarded as a basic acetylide of the formula 3C2Hg,2Hg(OH),. That the compound yields aldehyde and little or no acetylene when heated with acids may be due to the fact that acetylene hydrolyses with great readiness t o aldehyde in the presence of mercuric salts. I n the case of mercuric acetylide, C,Hg (Zoc. cit.), and hydrochloric acid, a considerable quantity of aldehyde is formed, and as in the com- pound we have just described, mercury is present in greater propor- tion. More aldehyde is formed by the action of acids. The hydrolysis of acetylene to aldehyde hag never been carefully studied. The sub- ject is well worth investigation, particularly with the view of determining whether vinyl alcohol is formed as a half-way product. UNIVERSITY COLLEGE, LONDON.

ISSN:0368-1645    

DOI:10.1039/CT9028101270

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

1272 MELLOR AND RUSSELL: THE PREPARATION OF PURE CXXIX.-T%e Preparation of Puw Chlorine and its Behaviour to wards Hydrogen. By J. W. MELLOE and EDWARD JOHN RUSSELL. IT is not yet known who first discovered the curious suspension of chemical action often noticed between carefully dried substances which, in ordinary circumstances, react with one another. So far back as 1802, Mrs. Fulhame * pointed out that gold salts are not reduced either * Quoted in Thomson, A System of Chenzislry, vol. ii, p. 454, 1802.CHLORINE AND ITS BEEAVIOUR TOWARDS HYDROGEN. 1273 by hydrogen or by (‘ phosphorated ether ” unless first moistened with water, and she suggested a theory to account for the influence of water in chemical reactions. Higgins,” in 1814, observed that “ dry muri- atic acid has no action on dry calcareous earth, while these sub- stances readily unite if moisture is present.” I n 1837, BonsdorfE (Ann.Phys, Chern., 1837, 41, 293; 42, 325) demonstrated that atmo- spheric air freed from carbon dioxide and moisture does not tarnish clean surfaces of metallic potassium, arsenic, +f bismuth, lead (com- mercial or pure), zinc, cadmium, iron, or copper ; in 1838, Regnsult (Ann. Chim. Phys., 1838, [ii], 60, 176) failed to induce dry olefiant gas to combine with chlorine in diffused daylight ; E. A. Parnell (B.A. Reports, 1841, 51) drew attention t o the important part pIayed by water in chemical reactions and showed that whilst moist hydrogen sulphide acts vigorously on papers impregnated with salts of lead, mercury, and copper, there is no action if the hydrogen sulphide is well dried; and Andrews, in 1842, stated in a foot-note to one of his papers (Trans.Roy. Irish. Acad., 1842, 19, 398; or S c i e n t 9 c Memoirs, 1889, p. 90) that although moist chlorine combines energetic- ally with zinc, copper, and iron-filings, perfectly dry chlorine ‘‘ has no action whatever a t ordinary temperatures . . . . the same remarks may be applied to the behaviour of dry bromine in contact with dry metals.” Kolb (Compt. rend., 1867, 64, 861; see also Debray, ibid., 1848, 26, 603) showed, in 1867, that dried oxides and hydroxides of calcium, barium, magnesium, sodium, and potassium do not increase in weight in an atmosphere of dry carbon dioxide. I n 1869, came Wanklyn’s observations (Chern. News, 1869, 20, 271) that sodium and chlorine do not unite; this is sometimes said to be the earliest record of the influence of small quantities of water in promoting chemical action, although, as Dixon (Trans., 1896, 69, 775) has pointed out, Wanklyn does not state whether moisture has any effect or not on the combination.Dubrunfaut (Compt. rend., 1871, 73, 1395) was under the impression that water assists the combustion of carbon, but his experiments were far from being conclusive, and he did not reply to Dumas’ statement (Compt. rend., 1872, 74, 13) that pure graphite burns completely in oxygen dried by sulphuric acid. I n 1880, Dison (B.A. Reports, 1880, 593) opened up the way for systematic research on this subject. Baker (Trans., 1894, 65, 611) has compiled a list of papers published between that date and 1894.We have made some experiments with the object of finding whether pure chlorine will combine with dry hydrogen. Armstrong, in his * Higgins’ Experimem% and Observations on the Atomic Theory, 1814 ; we are in- debted to the kindness and courtesy of Dlr. V. H. Veley for these two references. t Bonsdorff states that Bergmann had previously demonstrated that dry air had no action on metallic arsenic.1274 MELLOR AND RUSSELL: THE PREPARATION Ol? PURE Presidential address to the Eiitish Association at Aberdeen in 1885, expressed the belief that there would be no action between the pure gases. Dixon and Harker (Maizchester Memoirs, 1889, [iv], 3, 118 ; 1890, [iv], 4, 1) found that the more carefully the mixed gases were dried, the greater the intensity of light required to cause detonation, but an electric spark always caused an explosim a t once, no matter how carefully tho gases were dried, and measurements of the rate of pro- pagation of the detonation wave showed that this rate was rather greater in dry gases thanin moist.* I n other words, rnoisture retards rather than accelerates reaction under these conditions.Pringsheim (Ann. PAYS. Chem., lSS7, [iii], 32, 422) published an investigation on the union of hydrogen and chlorine, and showed that when heated the dried gases exploded a little later than the moist gases, but just as violently. He also found that the dry gases explode in sunlight with a feeble clicking sound. I n 1894, Baker confirmed Dixon and Harker’s observation on the effect of light, and prepared a mixture which did not explode on exposure to sunlight, and of which only 75 per cent.combined in fnur days. I n most of the investigations mentioned above, the mixture of gases was obtained by electrolysis of hydrochloric acid in aqueous solution, but oneof us has shown (Mellor, Trans., 1901, 79, 225) that traces of oxygen are always present in the electrolytic gases, and, although it might be possible to remove this by subsequent treatment, we considered it safer to adopt a method for preparing the gases which would preclude the possibility of oxygen or a chlorine oxide being present. Preparc6 tiom of Pure Chlorine. Shenstone has shown (Trans., 1897, 71, 471) that the most trustworthy method by which pure chlorine can be obtained is the electrolysis of fused silver chloride.I n our first experiments, we closely followed Shenstone’s instructions, and in fact he kindly supplied us with a number of carbon electrodes ; these mere made from carbon filaments used for 250 c.p. incandescent lamps flashed on to stout platinum wires. Although we obtained a small quantity of pure chlorine in this way, we experienced two difficulties. I n the first place, we were unable to obtain a supply of electrodes which worked as well as those Mr. Shenstone kindly gave us; those sent by the same makers were very apt to disintegrate under the conditions of our experiments and were altogether untrustworthy in protracted operations at high temperatures. In the second place, w0 found it very difficult to prevent contact between the silver chloride and the platinum wires.* The mean rate of explosion in dried mixtures of hydrogen and chlorine was 1795 metres per see. In moist mixtures, 1770 metres per sec.CRLORINE AND ITS BERAVIOUR TOWARDS HYDROGEN. 1275 Even a small quantity of silver chloride on the wire at-tacks it t o such an extent as to ruin the experiment. We therefore adopted the following modification and find it to be a fairly easy and practical method for preparing large quantities of pure chlorine. The Silver Chloride.-About 600 grams of purified silver chloride were fused in a basin and kept in that state for four or five hours to drive off all the water. After cooling, the horny mass was cut up into small pieces and placed in the electrolytic vessel.The electyolytic vessel was a V-shaped tube of the hardest Jena glass, 3 cm. in diameter. One arm is shown in section in Fig. 2 (p. 1276) ; a side tube was sealed into each limb. The electrodes consisted of stout carbon rods, 30 em. long and 5 mm. in diameter, specially prepared by Conradty of Nuremberg at a high temperature for the electrolysis of fused salts. The method by which FIQ. 1. Apparatus for th,c preparation, &e., of pzcre chlorine. these were fixed into the electrolytic vessel will be readily understood on reference to Fig. 2. A piece of hard Jena glass tubing about 100 cm. long and of just suEcient diameter to allow the carbon rods t o pass through was sealed on to a short piece of tubing of about 1 cm. diameter ; a constriction mas then made in each limb of the V-tube, leaving just sufficient space for the narrower part of the tubes just mentioned to pass freely in and out.The carbon rods were then passed through the inner tube, thick plaster of Paris was poured in and over that sodium silicate which was drawn in to the plaster of Paris by pumping out air from the other side. After a little time, mercury was also added to surround the projecting part of the electrode and allow electrical contact to be made. I n Fig. 2, E represents the carbon rod, D the glass tube surround- ing it, C the plaster of Paris plug, B the layer of mercury into which1216 MELLOR AND RUSSELL: THE PREPARATION b~ PURE the rod E projects, and ,4 a lnper of sodium silicate. When D is carefully chosen and the constriction sufficiently well made, the surface of plaster exposed to the interior of the vessel is extremely small.This joint is perfectlyair-tight and is capable of retaining a vacuum for weeks. It has to be protected by asbestos paper from heat radi- ated from the flame or it tends to crack, In order to connect the hard Jena glass of the electrolytic vessel with the soft glass of the rest of the apparatus, we made similar joints at b (Fig. I, p. 1275), one of which is also shown in section in Fig. 2. Section of one limb of electrolytic vessel. The electrolysis being started in a vacuum, it is obviously necessary to connect each limb of the electrolytic vessel with the apparatus in order to keep the level of the molten silver chloride the same in both. The V-tube was then placed in a copper bath, packed with asbestos, and heated by means of two blow-pipes until the silver chloride had fused.An automatic Sprengel pump, working continu- ously for two days, exhausted the apparatus and removed the greater part of the moisture given off at this high temperature by the plaster of Paris and any gases that might be occluded in the electrodes. A current of 2.8 amperes (10 volts) was now passed, and chlorineCHLORINE AND ITS BEHAVIOUR TOWARDS HYDROGEN. 1217 was liberated in a fairly steady stream; the current mas sent some- times in one direction and sometimes in the other to sweep out com- pletely any trace of air or moisture from both limbs and electrodes. This was continued at intervals for two or three days; during the whole time the temperature was kept as high as was consistent with the safety of the vessel, and the pump remained working.A metre column of fragments of solid potash (e, Fig. 1) not being sufficient to protect the pump from chlorine, we devised the mercury wash-bottle shown a t C . By adjusting the height of the reservoir d, the gas can be made either to pass over the surface or bubble through a column of mercury as may be required. A fairly clean surface can always be obtained. A jar of mercury was put round the junction of the rubber and the glass to prevent air leaking in. The mercury washer and the potash column effectually prevent any chlorine from reaching the pump. The silver tree has been a fertile source of trouble in preparing pure chlorine by the electrolysis of silver chloride. Our electrodes being very stout, we were able, without injuring the apparatus, to adopt drastic measures, which proved entirely successful in dealing with this trouble.When the ammeter showed that some irregularities were beginning:in the electrolytic cell, we raised the temperature almost to the softening point of the glass and cut out all the external resistance so as to simultaneously increase the current. The increased current at the elevated temperature melted or shattered the silver tree, and electrolysis was discontinued for a short time until the former temperature was restored. When electrolysis started again, it was found to proceed quite normally. When it was thought that all foreign gases had been removed, the pump was shut off and the apparatus allowed to fill with chlorine.One of the test-tubes (Fig. 1) was sealed off and its point broken under mercury. Perfect absorption took place ; we could detect no trace of residual gas. Nevertheless, we exhausted the apparatus and filled again, repeating the operation four times in all. Each time, samples were taken and absorption of chlorine by the mercury was invariably complete. The pressure of chlorine in the apparatus during the last filling was determined by one of us momentarily opening the mercury gauge f, which had previously been exhausted with the rest of the apparatus but shut off during the evolution of chlorine, while the other read the depression produced. As the mercury was covered with a thin film of glycerine, a reading, probably correct to 1 or 2 mm., was obtained before appreciable absorption began.The Preparation of Pure Hydrogen.-Here we followed Scott’s directions (Phil. T!*anns., 1893, 184, 548) in which hydrogen was1278 MELLOR AND RUSSELL: THE PREPARATION OF PURE prepared i n the first instance by the action of steam on sodium, and subsequently absorbed by palladium to allow gaseous impurities to be removed by the pump. The apparatus (Fig. 3) having been exhausted, the water in A was gently heated, the steam in contact with the sodium in B generated hydrogen which passed through the phosphoric oxide contained in C and was absorbed by the palladium foil * in the tube D. The experimental vessels were, of course, shut off. D was surrounded by a bath of paraffin, which, during the preliminary exhaustion, was kept at a temperature of 1SO'.While hydrogen was being generated, the temperature was allowed to fall to that of the room ; the absorption was rapid bet ween 120' and 80'. When D was cold, the flasks A and B were shut off and the pump kept working to exhaust the tube D and the experimental vessels. After exhaustion, D was heated until sufficient hydrogen was obtained to fi11 the apparatus to the same pressure as the chloriue. FIG. 3. Apparatus for the preparcbtion of pure hydroyea. The Experimental Vessels.-We have adopted an old method of Professor Dixon's for mixing the gases by the use of the double-bulb condensers employed with Soxhlet extractors. Out of a large number, those were selected which had approximately equal capacities for the inner and outer bulbs.After sealing platinum wires to the tube leading to the outer bulb in each condenser, they were connected in the manner shown in Fig. 1 and carefully cleaned by boiling with concentrated nitric acid, well washed in distilled water, and dried at a high tempera- ture in a current of dry, dust-free air. A quantity of phosphoric oxide, carefully purified by slow distillation in a current of oxygen over red-hot, spongy platinum, was introduced into each of the inner and outer bulbs. A small piece of glass rod with sharp edges was also placed in each inner bulb. The inner bulbs * We wish to thank Messrs. Johnson and Matthey for kindly lending us the palladium used in this research.CHLORINE AND ITS BEHAVIOUR TOWARDS HYDROGEN. 1279 being all in communication with each other were filled with chlorine, the outer ones with hydrogen.The glass springs shown in the figure were used i n order t o prevent any danger of snapping through too great a rigidity. After the vessels had been filled with the gases, they mere sealed off and left to dry in the dark for nine months. Immediately before an experiment, the bulbs were shaken in a dark place so as t o break the inner one, and a sufficient length of time allowed to elapse to ensure complete diffusion. Behaviour of the Mixture of Chloride and liydrogen. (1) Action of the Electric Xpark.-A small spark a t once caused a violent explosion, shattering the whole apparatus. The bulbs had been surrounded by a stout bell-jar so that the gases could be drawn over heated copper oxide to estimate the amount of hydrogen left over, but so little was found that we mere forced to the conclusion that combination had been complete, (2) Action of Heat.-We found that mixtures of moist hydrogen and chlorine in similar bulbs explode in the neighbourhood of 260".One of the bulbs was therefore heated rather above that temperature (270') for some minutes, but no explosion took place. The bulb was allowed to cool and the gases pumped out and analysed. Very little combination could be detected, practically the whole of the hydrogen and chlorine were recovered in the free state. Another bulb was now heated for ten minutes to a higher tempera- ture, namely, 450O. Still no explosion occurred. Analysis showed that combination had taken place, but not completely; about 80 per cent.of the mixture had combined. On examining the bulb, it was evident that the phosphoric oxide had fused, and some had volatilised. It is unfortunately necessary to scatter the phosphoric oxide over the whole of the glass in order to remove moisture a s quickly as possible, chlorine and water-vapour being likely t o react with one another. We were not able to heat the gases without a t the same time heating the phosphoric oxide. (3) Action of Sunlight.-On exposure to bright sunshine a t Wye, in June, no explosion took place. The bright sunshine lasted for three days. At the end of that time the bulb was opened and the gases analysed. About 30 per cent. of the hydrogen and chlorine had combined. Our experiments, therefore, lead t o the conclusion that an electric spark causes an explosion in the dried, just as readily as in the moist, gases. Combination is complete, showing that the action is propagated through the whole mass of the gas. Neither heat nor sunshine1280 MELLOR: THE UNION OF HYDROGEN AND CHLORINE. causes explosion in the dried gases; combination, when it occurs at all, is very slow and incomplete, and not transmitted through the whole of the gas as in the previous case. Why there should be this difference, and whether the slow combination which we find is a direct action or due to a surface action, we are not at present in a position t o say. Our best thanks are due to Professor Dixon for much kindly help and encouragement in this research, and to Mr. W. A. Shenstone, F.R.S., for supplying us with some of his electrodes and for giving us some valuable suggestions as to the preparation of the chlorine. THE OWENS COLLEGE, MANCHESTER, AND SOUTH EASTERN AGRICULTURAL COLLEUE, WYE.

ISSN:0368-1645    

DOI:10.1039/CT9028101272

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

1280 MELLOR: THE UNION OF HYDROGEN AND CHLORINE. CXXX.-The Union of Hydrogen and Chloyine. V. The Action of Light on Chlorine Gas. By J. W. MELLOR. IN 1843, Draper announced to the British Association Meeting at Cork (B.A. Reports, (‘Abstracts of Communications,” 1843, 9 ; Phil. Mag., 1844, [ iii], 25, l ) , ‘‘ chlorine gas which has been e x p o s a t o daylight or sunshine possesses qualities which are not possessed by chlorine which has been made in the dark. This is shown by the circumstance that chlorioe which has been exposed t o sunshine has obtained from that exposure the property of speedily uniting with hydrogen gas, a property not possessed by chlorine which has been made and kept in the dark. This quality gained by chlorine arises from its having absorbed tithonic rays* corresponding in refrangibility to the indigo.It is not a transient, but a permanent, property, the rays so absorbed becoming latent and the effect lasting an unknown time.” Draper’s experiment in support of this important statement was performed in the following manner. Equal volumes of chlorine were introduced into similar clear glass tubes and confined over salt water. The gas in one vessel was exposed to bright sunshine, while the other was kept in darkness. After a quarter of an hour’s time, an equal volume of hydrogen was added to each tube, and both tubes were then exposed t o diffuse daylight. The insolated chlorine united 6‘ promptly and energetically ” with hydrogen ; the chlorine made and kept in the dark showed no such property. * Now called “actinic.V. THE ACTION OF LIGHT ON CHLORINE GAS.1281 I n a later paper (Phil. Jhag., 1845, [iii], 2’7, 327), Draper described a modification of the above experiment in which the chlorine, dried by calcium chloride, was not allowed to come into contact with the salt water during the exposure to light, but with the same result. Draper also showed that this phenomenon is not due to the heating effect of the sun’s rays, because the chlorine will retain ics induced activity when kept some hours in the dark. I n his view, his experi- ments indicated that chlorine must be subject to a preliminary insolation before it can combine with hydrogen. In other words, chlorine after exposure to sunlight is more active chemically than chlorine made and kept in darkness.This interpretation of these experiments would furnish a simple enough explanation of the so-called period of photo- chemical induction if other investigators, working with more refined instruments, had been able to confirm Draper’s observations. The facts are as follows. In 1853, Favre and Silberrnann (Amrt. Chim. Phyls., 1853, [iii], 37, 499) quoted one experiment in which insolated chlorine was absorbed by a solution of caustic potash. They found that 478.8 calories of heat were evolved, whilst ordioary chlorine, under like conditions, gave 439.7 calories. These investigators also stated that a greater amount of chlorate was present among the products of the former reaction. On account of the complex nature of the reaction between chlorine and caustic potash, I have measured the thermal value of the simpler reaction between chlorine and potassium iodide. The gas was passed through a long spiral, kept at a constant tempera- ture, and then led directly into 500 C.C.of a decinormal solution of potassium iodide contained in a platinum calorimeter and constantly stirred by means of a platinum stirrer.’ A Beckmann thermometer was used in the calorimeter. After the temperature readicgs had been completed, the mass of chlorine which had entered the solution mas determined by titration of the free iodine with sodium thiosulphate. Otherwise I followed the details given in Thomsen’s Thermochemische Untersuchungen (1882, 2, 21, 29). The following values of R (= 100 calories) were obtained : Non-inaoIated chlorine. Insolated chlorine.283 282 287 286 281 285 I have also employed Carnot’s method (Compt. Tend., 1896,122,449) for the determination of the amounts of chlorides, chlorates, and hypo- chlorites in the products of the action of insolated and of non-insolated * I desire to take this opportunity of thanking Mr. Hartog for the loan of his VOL. LXXXI. 4 Q platinum apparatus,1282 MELLOR: THE UNION OF HYDROGEN AND CBLORINE:. chlorine on caustic potash. dekanormal solutions of potassium hydroxide at 20' :* The following results were obtained with Non-insolated chlorine. Insolated chlorine. Hypochlorite. Chlorate. Hypochlorite. Chlorate. - Y 71-58 per cent. 0.53 per cent. 70.34 per cent. 0.57 per cent. 71.72 ,, 0.47 ,, 72.01 ,, 0.51 ,, The chlorides are given by difference, total chlorine being determined as silver chloride.So far as these experiments go, the evidence in favour of the assumed existence of Draper's allotropic chlorine is not convincia g. Bunsen and Roscoe (Phil. Tram., 1857, 146, 398) failed to detect any difference between the rates of combination of hydrogen and non- insolated chlorine and of hydrogen and insolated chlorine in their extremely sensitive actinometer or to detect any action between hydrogen and insolated chlorine in the dark. t Askenasy and Meyer published the following experiment in 1892 (Annalen, 269, 72). Chlorine was exposed to bright sunlight concen- trated by means of a concave mirror and then mixed with a known volume of hydrogen in the dark. After the lapse of three or four hours, the gases were driven from the apparatus by means of a current of carbon dioxide; analysis failed to detect any difference in the quantity of hydrogen before and after contact with insolated chlorine.This experiment does not compare in delicacy with Bunsen and Roscoe's test. Traces of hydrogen could easily escape detection. Repetition. of Draper's Experimenta Two bulbs, A and B, each about 100 C.C. capacity, were connected with three cocks, a, 6, c, as shown in Fig. 1 (p. 1283). At one end, c, a capillary tube dipped into a concentrated solution of sodium chloride.$ Chlorine was led through the three-way cock b, into R and out a t D, until all the * A t temperatures above SO", the yields were very irregular. A difference of a few minutes in the time of passing the gas into the solution will make a marked differ- ence in the yield of chlorate owing to the decomposition of the hypochlorite.Fuller details will be given in another communication. j. Amato (CT'axzetta, 1884, 14, 57) states that an explosive mixture of hydrogen and chlorine will not explode in sunlight a t - 12" provided that the chlorine has not been snhjected to a preliminary insolation. No experiments are given with insolated chlorine. Butlerow and Rizza (Bull. SOC. Chim., 1882, [ii], 38, 554 ; 1883, [ii], 39, 263) appear to have also determined the atomic weights of insolated and non-insolated chlorine. $ Chlorine dissolves in, or otherwise attacks, all liquids available for use in the measuring gauge. I have always employed sulphuric acid saturated with chlorine gas unless there were special reasons, as here, for using another liquid.I have modified Draper's experiments in various ways.V. THE ACTION OF LIGHT ON CHLORINE GAS. 1283 air had been driven out of this part of the apparatus, and the salt water was saturated with the gas. The three-may cock was then closed. A was then filled with hydrogen in a similar manner with hydrogen escape at a, The cocks were lubricated with glacial phos- phoric acid. The apparatus was then exposed to bright sunIight (midsummer, 1901) for a couple of hours and then removed into a dark cellar. A and B were placed in communication for 8-10 hours by opening the cock 6. The index at first indicated that the chlorine had expanded during insolation, but in 8-10 hours the original volume was restored.There was no contraction which could be attributed to the combination of hydrogen with chlorine when allowance was made for changes of the atmospheric temperature and pressure. It will be e B 6 A a FIG. 1. evident that if the insolated chlorine had been allowed to regain atmospheric pressure by allowing some chlorine to escape before open- ing the cock 6, as, I believe, happened in many of Draper’s experiments, we should have a contraction of the expanded chlorine which has hitherto been thought to be due to the formation and subsequent absorption of hydrogen chloride by the salt water. The bulb, A, was then filled with a known volume of hydrogen at about half the atmospheric pressure ; B was filled with chlorine at atmospheric pressure. The chlorine was then exposed to sunlight and mixed with hydrogen, as before, in the dark. Next day, the mixture was swept into a burette containing an aqueous solution of caustic potash by means of a current of carbon dioxide.- Four measurements are given in the following table :1284 MELLOR: THE UNION OF HYDROGEN AND CHLORINE.Observed' 52.6 53.2 53.3 52.0 Before exposure. Reduced t o N. P. T. 50 *7 50% 50 *1 49'9 17.6" 17.8 175 17'8 Vol. at N. P. T. C.C. 771 770 777 778 50.1 50.0 50.5 49-8 Temp. 14%" 15 *1 15.3 15.0 Eight hours after exposure. Bar. mm. 773 762 770 770 - Volume C.C. Diff. c. c. + 0-6 + 0.5 - 0.4 +0*1 - I have also used the method adopted by Dixon and Peterkin (Trans., 1899, 75, 613) for observing the change in the volume of mixed gases. The inner bulb of a ball condenser was filled with hydrogen, the outer with chlorine; the mixing of the gases after exposure to sunlight was effected by breaking the inner bulb by means of a piece of glass rod previously placed inside.No evidence was obtained of any combina- tion in the dark. I am consequently led to conclude that the contraction which Draper attributed to combination of hydrogen was, in most caBes, a secondary effect of what may be called the photo-expansion of chlorine (the Budde effect), namely, the contraction which insolated chlorine always undergoes on removing the light, The Bzldde Efect. I n 1870, Budde (Phil. Mag., 1871, [v], 42, 290; Pogg. Ann. Ergbd., 1873, 6, 477) discovered the fact that chlorine expands under the influence of light rays of high refrangibility. The temperature of the chlorine rises about one degree.This is not a direct heating effect of sunlight, because the interposition of a screen of water between the source of light and the chlorine makes no difference to the effect. Favre and Silbermann (Zoc. cit., p. 499, footnote), so far back as 1853, tried the same experiment as Budde, but with a negative result. As a matter of fact, no change in volume does occur if the chlorine is thoroughly dried (Roscoe, Watts' Dictionary, 1875, 7, 750 ; Baker B.A. Reports, 1804, 493; Shenstone, Trans., 1897, 71, 471). Richardson, however, has not only established the reality of the Budde effect (Phil. Mag., 1891, [v], 32, 277), but he has also shown that the magnitude of the photo-expansion is proportional to the intensity of the more refrangible rays of light, Hence he utilises this property to measure the intensity of rays of high refrangibility.TheV. THE ACTION OF LIGHT ON CHLORINE GAS. 1285 expansion is independent of temperature between the limits 14’ and 1 3 8 O . I f I denotes the intensity of the light and ZI the volume of the chlorine, I = av, where a is a constant very nearly equal to 70. The expansion occurs when chlorine is mixed with air (Richardson), or with hydrogen, carbon monoxide, or ethylene (Recklinghausen, Zed. physikaZ. Chern., 1894, 14, 494). (‘ Ausdehnung durch die Reak- tion,” says Recklinghausen, ‘‘ scheint demnach das Charakteristikum einer durch das Licht stattfindenden Vereinigung zweier Gase zu sein.” Recklinghausen also measured the magnitude of the photo-expansion of chlorine mixed with hydrogen, not directly in contact with water, in an apparatus in which the mechanism of a plethysmogreph is ingeniously applied to measure slight changes in volume.He found that as the chlorine disappeared, owing to the formation of hydrogen chloride, the mixed gases returned to their original volume. When the light was removed a t any stage of the exposure, the mixture also returned to its original volume. If the light were again restored, the mixture again expanded, but not quite to the volume occupied just before the light was removed. From this, Recklinghausen argues that it is possible combination takes place in the dark. Another interpretation may, however, be suggested. The total increase in the volume of the actively combining gases is the additive effect of (1) Budde’s photo-expansioo, and (2) the heat of combination of hydrogen and chlorine gases.I n darkness, combination ceases, the mixture cools. When light is restored, the resulting expansion is the joint effect of the photo-expansion of the remaining chlorine and the heat of combination of the newly formed hydrogen chloride without the thermal effect which accompanied the formation of the hydrogen chloride produced during the first exposure. Budde has suggested the following possible explanations of his dis- covery : (1) Light loosens or decomposes the chlorine molecule into free atoms, so that c1, = c1 + c1. Two volumes. Four volumes. (2) Light performs some work which changes into heat, thereby oaus- ing an expansion.(3) The chlorine is warmed up directly in the same way that lamp black is warmed up in the heat spectrum. He rejected the second of these suppositions as a makeshift (Nathbehelf) ; the third he rejected because the heat rays at the red end of the spectrum pro- duce little, if any, photo-expansion. The first supposition appeared to1286 MELLOR: THE UNION OF HYDROGEN AND CHLORINE. explain most of the facts, and he suggested that the slight rise of temperature was developed by the recombination of the ‘‘ gelockerten und zersetzen Clhlormolekule.” The first question I have attempted to answer is : Does the rise in temperature account for the expansion 1 Professor Dixon has suggested to me the following instrument. The two concentric bulbs of a ball condenser (Fig.2) were respectively fused on to two sulphuric acid gauges, The outer bulb was filled with chlorine, the inner with air, so as to form an air thermometer sur- rounded by the chlorine. The stem of each bulb was graduated by warming up the bulbs in a suitable vessel and marking the position of the index in each stem a t the different temperatures. The two indices show practically the same rise of tempera- ture when the bulbs are placed in a water-jacket and bathed in sunlight. The sir thermometer probably shows more correctly the temperature of the surrounding chlorine than a mercurial thermometer. FIG. 2. The photo-expansion is therefore proportional to the temperature of the gas, and it is unnecessary to as- sume that the chlorine molecule is dissociated when exposed t o actinic light. Measurements of the conductivity of the illuminated gases confirm this conclusion. J.J. Thomson (Proc. Camb. Phil. SOC., 1901, 11, 90; see also Hemptinne, Zeit. physikal. Chem., 1902, 12, 244) has experimented on this subject. He says: “The object of these experiments was (1) to see whether there were any free ions present either in the preliminary stage when the expansion discovered by Draper is oc- curring, or (2) when the hydrogen chloride is being produced. At neither stage could I detect any free ions, although I could have done SO had the ions amounted to anything like 1 in 1014 of the molecules present. I then tried whether the rate of combination was affected when ions were produced by external means, for example, Rontgen rays, thorium radiation, &c.I could not detect the slightest effect.” According to Clausius’ theory, for any given temperature there i s ~l definite relatios The results were negative. To return to the hypothesis rejected by Budde.v. THE ACTION OF LIGHT ON CELORINE GAS. 1287 between the molecular and the atomic energy of a gas, or between the rectilinear motions of translation and the vibrations of the molecules (or atoms). The former motions are supposed to determine the t e a - pernture of a gas as measured by a thermometer. If the molecular vibrations are augmented, the increased energy is converted into energy of translatory motion either after a few or after a great number” of molecular impacts. If the molecular vibrations are con- tinually excited by an impressed force, such as the absorption of light rays of a definite period of vibration, there will be a continuous trans- formation of this energy into energy of translatory motion, which makes itself evident by a rise of temperature.If the internal energy is not immediately dissipated by, say, radia- tions from the molecules moving in their free path between successive collisions, or by the conversion into heat during molecular impact, energy will be stored in the gas and ultimately make its appearance as luminescent or phosphorescent phenomena (Wiedemann, Ann. Phys. Chim., 1889, [ii], 37, 177; also Phil. Uag., 1889, [v], 28, 149, 248, 376, 493). I find that no radiations capable of affecting the fastest ‘‘ Paget ” sen- sitive plates? are evolved by chlorine gas contained in thin glass tubes exposed for 1-5 hours to bright sunlight, limelight, or to a 600-1000 c.p.electric arc ; nor does such a vessel of chlorine emit any rays capable of causing a perceptible influence on a sensitive mixture of hydrogen and chlorine, A layer of 15 cm, of moist chlorine appar- ently affords perfect protection from the actinic rays capable of effect- ing the union of hydrogen and chlorine. The actinic energy from sunlight is apparently absorbed and subsequently dissipated in the form of non-actinic external radiations. If the amount of expansion of isolated chlorine could be taken as a measure of the work performed by the absorbed actinic energy, a simple calculation would furnish the thermal equivalent of any ray of light absorbed by the chlorine.If the gas obeys van der Waals’ law, for example, the work of isothermal expansion is where a and 6 are van der Waals’ constants, R is the gas constant, 8 the absolute temperature, vl the initial, v2 the final, volume of the gas. It is clear that if the ‘‘ kinetic potential ” of the energy changes * Stoney’s “88” and <‘Bb’’ events respectively (Stoney, PhG. Hag., 1895, + I desire to thank Mr. Bradley for doing the photographic work. Evl, 40, 262).1288 MELLOR: TEE UNION OT HYDROaEN AND CHLORINE. during the process of absorption-of light be studied thermodynamically, the entropy must, a t the outset, be divided into two parts. The one part corresponds with temperature as defined by the motion of the translation of the molecules which is indicated on the thermometer ; the other part corresponds with temperature ” as defined by the mole- cular (or atomic) vibrations and is not indicated on the thermometer.I have tried to find further indications of the nature of the internal work performed when light is absorbed by chlorine gas by comparing the ratio of the two specific heats for chlorine in sunlight, and chlorine in darkness, at the same temperature. I was unable to detect any difference outside the range of experimental error with an ordinary Kundt’s tube. This only shows that the change in the internal energy of the isolated gas is an immeasurably small fraction of the total energy of the translatory motions of the molecules. Chemical Action of Light on Moist Chlorine. Richardson (B.A. Reports, 1888, 89) has mixed moist carbon dioxide with sufficient chlorine theoretically to decompose all the moisture, and found that 1.33 per cent.of the chlorine had been con- verted into hydrogen choride after 33 days’ exposure to light ; when oxygen was substituted for the carbon dioxide, 3 per cent. of the chlorine was converted into hydrogen chloride in the same time. Pedler (Trans,, 1890, 57, 613) has investigated the action of tropical sunlight on chlorine in the presence of liquid water in sealed tubes. Hs found that little action occurred unless the water is in relatively large excess. Moist chlorine in the beam of a 600-1000 c.p. arc light concen- trated by a lens (about 12 in. focus) shows a faint cloudiness re- sembling the cloud observed by Tyndall (Tyndall’s ‘‘ Heat, a Mode of Motion,” 1880, 475) with sulphur dioxide and the vapours of certain organic liquids, I have separated a little oxygen* (about 4 per cent.of the total volume) by passing the illuminated gas from Tyndall’s tube, a t a temperature of 20-25”,l. into a cold solution of potassium hydroxide by means of a current of carbon dioxide. The oxygen was not due t o the action of chlorine on any visible moisture deposited on the illuminated parts of the apparatus. Morren (Ann. Chirn. Phys., 1870, [iv], 21,323) found that hydrogen chloride, similarly exposed to a beam of sunlight, was not decomposed. * It is extremely difficult to prepare large quantities of chlorine free from traces of air. By means of the process indicated in Part I, it is possible to prepare 10-14 litres of chlorine contaminated with immeasurably small amounts of air. Thig method of preparation was employed here.t. The gas in the vicinity of the focus of the lens is no doubt at a higher tempera. ture than this.V. THE ACTION OF LIGHT ON CHLORINE GAS. 1289 (i) Air in ,,. 2 1 3 a 13 12 14 16 18 18 If chlorine is dried by means of phosphoric oxide, there is no sign of Budde’s expansion in sunlight. (Concentrated sulphuric acid may be used as index liquid.) Consequently, the amount of actinic energy which is converted by dry chlorine into heat is not sufficient t o affect the chlorine thermometer above described. Cordier (Monatsh., 1900, 21, 660) finds that whilst moist chlorine is opaque, dry chlorine is more transparent than moist chlorine t o actinic light so far as the screening effect of chlorine on silver chloride is concerned. I have fitted up the insolation vessel of Bunsen and Roscoe’s actino- meter A B C (Fig, 3) in the middle of a large globe, D, filled with FIG.3. - (ii) Dry chlorine (iii) Moist chlorine in D. in D. 0 0 0 0 0 No action 0 observed. 0 0 1 2 chlorine gas. The large globe was painted in such a way t h a t the insolation vessel could be illuminated by a beam of light which had been filtered through 10-15 cm, of chlorine gas. The following numbers are representative of the readings : Time in miuutes. a 9 10 11 12 13 14 15 16 2012%) MELLOR: THE UNION OF HYDROGEN AND CHLORINE. The dry chlorine had been in contact with purified phosphoric oxide for five months.These results raise the question : Is the actinic energy absorbed by moist chlorine gas spent in doing chemical work? The reaction between chlorine gas and water vapour is endothermic (compare Namais, Gaxxettcc, 1896, 26, i, 35). The filtering of light from the actinic rays by moist chlorine is a continuous process. When a bulb of hydrogen and chlorine gas is placed in a sufficiently large jar of moist chlorine gas and exposed to light, the bulb is perfectly screened from the actinic rays for an indefinite period. If, therefore, the absorption of light induces the above reaction, there must be a point at which the reverse reaction takes place, and is reversible, Richardson (B.A. Reports, 1888, 89 ; 1889, 59 ; 1890, 263 ; Trans., 1887,51, 801) has demonstrated that hydrogen chloride in the presence of excess of oxygen is almost completely decomposed according to the reaction 4HCl + 0, = 201, + 2H,O.Harker (Zeit. physikal. Chem., 1892, 9, 673) has also established the reversibility of the reaction at high temperatures. There is a curious relation between the equilibrium constant and the intensity of light which remains to be investigated. If a mixture of equal volumes of oxygen, hydrogen, and chlorine be exposed to actinic light, the colour of the chlorine at first disappears owing to the relatively fast irreversible reaction 2H,O + 2C1, 0, + 4HC1, H, + C1, = 2HC1, this being followed by the slow reversible change, 4HC1 + 0, ZZ 2H,O + 2C1,, the characteristic green colour of chlorine slowly returns. Since the volume of moist chlorine is alone affected by the absorption of actinic energy, the increased temperature of insolated chlorine appears to be an effect of some chemical reaction between water vapour and chlorine gas.* The amount of moisture retained by a gas which has been in contact with any given desiccating agent a sufficient length of time for thorough desiccation is of vital interest.Dittmar and Henderson * E. R. Laird (Astrophysical Journal, 1901, 14, 85) has recently mapped the absorption spectrum of ordinary chlorine. A comparison of this with that of pure chlorine, thoroughly dried by means of specially purified phosphoric oxide, would up doubt furnish useful information on this subject,v. THE ACTION OF LIGHT ON CHLORINE GAS. 1291 (Proc. Roy. Xoc. Glasgow, 1891, 22, 33) found that air dried by calcium chloride may retain 0.001 gram of moisture per litre.Morley (Amer. J. Sci., 1885, [iii], 30, 140) found that the absolute amount of moisture retained by air dried by sulphuric acid (sp. gr. 1.8381) is 0.000002 gram per litre. Dibbits (Zeit. anal. Chem., 1876, 4, 180) found that air dried by sulphuric acid gave up 0*000008 gram per litre to phos- phoric oxide. If the degrees of accuracy of the two latter measurements permit a comparison, it follows that the absolute amount of moisture retained in a gas thoroughly dried by phosphoric oxide is immeasurably smaEZ. [NOTE ADDEDAUGUST 19 :-Mr, H. Brereton Baker, F.R.S., hasrecently discovered that “dry chlorine attacks platinum in light but not in darkness.” (Private communication.) It is thus to be expected that the heat of this chemical action will cause an expansion which, if sufficiently great, will more than counterbalance the contraction due to the absorption of chlorine in the formation of platinurn chloride.A t a meeting of the Chemical Society, in November 1900, in the discussion of an earlier part of this paper, Mr. Baker mentioned the fact that dry chlorine in the presence of platinum expands in sunlight.] Note on the Action of the EZectric Discharge on Moist Chlorine. According to Henry (Phil. D*ans., 1800, 190, 238), 1/35 volume of hydrogen chloride is decomposed by the passage of an electric spark through the gas, Vernon (Chem. News, 1891, 63, 67) found that the passage of a silent discharge through chlorine in an Andrews’ ozone tube resultsin a slight expansion due to the heating effect of the discharge.I have mixed hydrogen chloride and’ chlorine and repeated these experiments to try if ‘‘ nascent ” chlorine from the hydrogen chloride would form anything of tohe nature of C1, or HCl,, but without success.* If, however, air or oxygen be present, the ozone formed will react with the hydrogen chloride. Conclusions. 1. There is no experimental evidence to show that chlorine gas under the influence of light undergoes an? change capable of appreci- &ly affecting the chemical activity of that element towards hydrogen. 2. Part of the energy absorbed by moist chlorine from sunlight is dissipated as heat. This causes the Budde effect. * If a tube with platinum or platinum-iridium electrodes is used, there is invari- ably a contraction in the volume of the mixed gases due to the combination of chlorine with the metal of the electrodes. I have never met with a specimen of platinum capable of withstanding the action of chlorine for many days without the fQrmation of a reddish “rust ” of platinum chloride over its .wrface.1292 MELLOR: THE UNlON OF HYDROGEN AND CHLORINE. 3, Under the influence of light, chlorine sets up and maintains in a state of equilibrium a reversible reaction with water vapour, possibly 2H,O -I- 2C1, 4HC1 -I- 0,. 4. Dry chlorine does not exhibit the Budde effect. 5, The rise in the temperature of imperfectly dried chlorine when exposed to sunlight appears to be due to some chemical reaction between the moisture and the chlorine gas. 6. A layer of moist chlorine just thick enough to screen a bulb of mixed hydrogen and chlorine gases from chemical action is not sufficient to prevent chemical action if the chlorine is dried by means of purified phosphoric oxide. 7, The actinic energy continuously absorbed from sunlight by moist chlorine is continuously dissipated in at least three ways : (i) partly in maintaining the above chemical reaction ; (ii) partly by conversion into heat during molecular impacts ; (iii) partly as external non-actinic radiations from the molecules moving in their free path between mole- cular collisions. THE OWENS COLLEGE, MANC'HESTER.

ISSN:0368-1645    

DOI:10.1039/CT9028101280

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

1292 MELLOR: THE UNlON OF HYDROGEN AND CHLORINE. CXXX1.-The Union of Hydrogen and Chlorine. VI. Die Period of Induction. By J. W. MELLOR. THE experiments recorded in the preceding paper lead up to the study of the most interesting period of chemical reactions where the velocity gradually increases from zero to a final maximum value. Bunsen and Roscoe call this the u period of induction.” The pheno- menon at first sight appears to contradict the well established law of mass action, because if the reaction takes place directly between, say, two components, the maximum velocity must occur at the beginning of the reaction when the active masses of the reacting components are greatest, as in the action of chiorine on methyl ether in sunlight. ‘6Da,ns les premiers, l’attaque est excessivement vive, mais elle se ralentit imesure que la chloruration fait des progrks ” (Cahours, Compt.rend., 1846, 23, 1070). It is not satisfactory to postulate, with Berthelot and Gilles (Ann. Chim. Phys., 1862, [ iii], 62, 26), ‘‘ une sorte l’inertia de rbsistance b vaincre qui retard la combinaison dans les premiers instants.” Har- court and Esson (Phil. Trans., 1866, 156, 201), Naumann (Annalen,VI. THE PERIOD OF INDUCTION. 1293 1876, 160, 23), and Hell and Urech ( B e y . , 1880, 13, 531) assume that the period of acceleration is due to the fact that '(chemical change consists in the gradual formation of a substance "-the so-called inter- mediate compound-" which at the same time slowly disappears by reason of its reaction with a proportional quantity of a third sub- stance." According t o this view (the intermediate compound theory), the reaction between hydrogen and chlorine in the presence of moisture may be written : CI, + H,O = X + &C.; (X + &c.) + H, = H,O + 2HC1, where X represents the unknown intermediate compound.Although the intermediate compound formed in many reactions has been isolated, with hydrogen and chlorine, unfortunately, indirect evidence is alone available. The reaction is usually studied in Bunsen and Roscoe's actinometer. The mixed hydrogen and chlorine gases are confined in a flak glass bulb (called the '' insolation vessel "), one-third filled with water satur- ated with the two gases. The insolation vessel is connected with an index which is very sensitive t o changes of volume, The lower half of the insolation vessel is painted black in order to screen the water from the influence of light.When the insolation vessel is illuminated, hydrogen chloride is formed and absorbed by the water. The index movements show that the rate of formation of hydrogen chloride gradually increases from zero up to a constant maximum velocity. The rapidity of induction and the rate of formation of hydrogen chloride are each proportional to the intensity of the light. Obviously, a certain amount of hydrogen chloride must be formed before the water begins to absorb this gas a t a constant rate. The rate of absorption of hydrogen chloride by water diminishes as the extremely thin layer of water in immediate contact with the gas approaches saturation.The denser solution of hydrogen chloride formed a t the surface sets up irregular convection currents during its descent to the bottom of the insolation vessel. Such currents are almost absent if ammonia gas is being absorbed instead of hydrogen chloride. The rate of absorption then depends on the rate of diffusion of the dissolved gas from above downwards. The amount of hydrogen chloride which the atmosphere above the water can hold before absorption begins is very small, as will be shown in Part TI1 of this investigation. The period of induction cannot be explained by the delayed solution of hydrogen chloride. Harden and Upon (Proc., 1894, 10,165) have observed a well-defined period of induction with carbon monoxide and chlorine. In this case, the1294 MELLOB: THE UNION OF ~YDROGEN AND cE~LoR~NE].velocity of the reaction is measured by the difference in the pressure of the gas on both sides of the equation C1, + GO = COC1,. Bunsen and Roscoe’s period of induction is sometimes sub-divided into (1) a period of inertness, during which there is supposed t o be no formation of hydrogen chloride, and (2) a period of acceleration. From the results recorded in Part IV of this work, however, it appears that there is no such thing as a period of no Formation of bydrogen chloride (MeIIor and Anderson, Trans., 1902, 81,414).* Assuming the existence of a n intemaediate compound, the period of induction is a necessary consequence o f the bw of mass action. A t the beginning of the reaction, the rate of diminution of chlorine is a maximum, whilst the rate of formation of hydrogen chloride is zero.From that moment, the rate of formation of the intermediate compound X is always equal to the difference in the rate of diminution of chlorine and the rate of formation of hydrogen chloride. During t h e first period of the reaction, the amount of X in the system con- tinually increases, and the system contains the greatest amount of X at the moment when the rate of diminution of chlorine is equal t o the rate of formation of hydrogen chloride. I n symbols, if x, y , x respectively denote the amounts of chlorine, X, and hydrogen chloride in the system a t the time t, then Again, from the law of mass action, the rate of formation of hydrogen chloride will be greatest when the system contains a maximum amount of X.But if y be a maximum, - dY =o, d t , dx dx ” dt dt’ - - = - The rate of formation of hydrogen chloride, therefore, gradually in. creases from zero, a t the beginning of the reaction when y=O, up t o a maximum value when y is a maximum. The so-called period of * The fact that hydrogen chloride is formed during the momentary illumination of a mixture of hydrogen and chlorine was published sin~ultaneously by P. V. Bevan (Proc. Camb. Phil. Xoc., 1902, 11, 264). Mr. Bevan experimented with a platinum wire placed in a mixture of hydrogen and chlorine, and measured the rise of tem- perature which occur8 when the mixed gases are momentarily illuminated by the increase in the resistance of the platinum wire. He believes that the presence of the platinum did not interfere with his results, and concludes that the increase in volume during the Draper effect is equivalent to the heat generated by the combination of hydrogen and chlorine.Mellor and Anderson, however, aFparently obtained much greater expansions than could be explained in this manner.VI. THE PERIOD OF INDUCTION. 1295 acceleration then ceases. Consequently, the duration of the period of induction depends on the relative rates of formation of X and of hydrogen chloride. Pringsheim’s Intermediate Compound. Pringsheim (Ann. Phys. Chem,, 1887, [iii], 32, 384) sought to ex- plain the period of induction by assuming that chlorine monoxide is formed as an intermediate compound according to the following equations : Stage I.-CI, + H,O = C1,O + H, Stage 11.-4H2 + C1,O- = H,O + 2HC1 He appears to have been guided in the selection of chlorine monoxide by the fact that ‘‘ if hydrogen chloride were formed it would be absorbed by the water,” and he observed no change in the volume of the gas during the ‘‘ period of inertness.” First, no reason is offered why the chlorine monoxide formed during this period is not absorbed by the water, the relative solubilities of chlorine monoxide and hydrogen chloride being very nearly as 5 : 1.Second, from experi- ments previously cited, a real ‘‘ period of inertness ” does not exist. The mass law also requires that immediately the smallest trace of inter- mediate compound is formed, hydrogen chloride shall be produced with an infinitely small velocity. Pringsheim also believed that the volume of the intermediate com- pound X must agree with the equation : There are two objections to this conclusion.C3, + H,O = X + &c. n volumes vz volumes. So far as our present knowledge goes, this condition is by no means binding. There is no evidence to show whether the maximum amount of the intermediate compound present in the system when the rate of formation of hydrogen chloride is a maximum is small or great. According t o Recklinghausen (Zeit. physikal. Chem., 1894, 14, 494), when a mixture of hydrogen and chlorine gases, not in direct contact with water, is illuminated, the increase in volume is proportional to the intensity of the light. Bunsen and Roscoe’s actinometer shows that if the gases are in contact with water, the volume decreases.This contraction is the joint effect of a t least four measurable pheno- mena. (1) The contraction due to the absorption of hydrogen chloride ; (2) the evolution of chlorine from the water in the insolation vessel as hydrogen chloride is absorbed (Mellor, Trans., 1901, 79, 216); (3) Recklinghausen’s photo-expansion which, as he says, “ is characteristic1296 MELLOR: THE UNION OF EYDROGEN AND CHLORINE, of a combination (of chlorine with hydrogen, &c.) induced by the light,’’ and which is sometimes as great as 4 per cent. of the whole; (4) the heat of combination of hydrogen and chlorine. If the volume of the intermediate compound does not agree with the above conditions, a fifth factor must be included, namely, ( 5 ) the change in volume due to the formation of the small or great quantity of the intermediate compound.Becquerel (WUT~Z’S Diet. de Chim., 1879, 2, 255), Veley, (Phil. Mag., 1894, [v], 37, 170), and Gautier and Helier (Compt. rend., 1897, 124, 1268), modify Pringsheim’s cycle and assume that the reaction occurs in the following way : STAGE I.-CI, + H20 = HOG1 + HCl CYCLE II. STAGE 11.-H, + HOCl = H20 + HC1 1 Veley gives two reasons for the rejection of Pringsheim’s cycle. (1) ‘‘ It is not probable that the anhydride C1,O would exist as such in the presence of water.” (2) “The investigations of Pedler . . . have shown that chlorine in the presence of water and under the influence of sunlight, the two conditions required, give HOCl as one of the intermediate products of the reaction. . .” In the first place, it is not known whether the vapour of hypochlorous acid is CI,+€€,O (vapour), or HOG1 molecules; nor is it known whether moist chlorine monoxide consists of C1,O + H20 (vapour) or HOCl molecules, yet there is no more reason to suppose that the anhydride C1,O does not exist as such in the presence of water vapour than that SO,, &c,, do not exist as anhydrides under similar conditions. I n the second place, it must be borne in mind that Pedler’s work referred to the action of light on aqueous solutions of chlorine and not particularly to chlorine gas mixed with aqueous vapour.The reaction in the former case is exothermal (Mellor, Trans., 1901, 79, 223, 225 ; see also Richardson, B.A. Reports, 1888, 89), whilst in the latter it is endothermal. There is no satisfactory method for the determination of the amount of hydrogen hypochlorite or of chlorine monoxide in the presence of chlorine, and no experimental evidence has hitherto been published which woald justify the selection of the one intermediate compound in preference to the other.A p i o r i , it appears very probable that either the first or the second of the above cycles represents the actual mechanism of the reaction under consideration. The following considerations have led me to abandon both. I have measured the duration of the period of induction and the rate of formation of hydrogen chloride in the presence of hydrogenVI. THE PERIOD OF INDUCTION, 1297 hypochlorite and of moist chlorine monoxide* in a Bunsen and Roscoe’s actinometer modified as shown in the figure.The top of the insolation vessel A was connected with capillary tubing (about 1 mm. bore) B and C. C was filled with the desired vapour under a pressure of 1-5 mm. of mercury in excess of the prevailing atmospheric pressure. This arrangement was fused at 13 to the exit tube of an ordinary actinometer so that the insolation vessels of both actinometers could be illuminated with the same light. By suitably turning the three-way cock 6, both actinometers can be filled with the same mixture of hydrogen and chlorine. The light FIG. 1. was placed so that both actinometers gave identical readings. The light was then extinguished and a little more chlorine-hydrogen mix- ture was sent through the apparatus. A and C were then placed in communication for a moment so that a little of the gas in C passed into A .As soon as equilibrium was restored (about five minutes are re- quired), the two bulbs mere again illuminated. The following numbers are four sets of readings of the two actinometers standing side by side : * The strongest solutions of hypochlorous acid, free from chlorine, can be pre- pared by passing a current of carbon dioxide through an aqueous solution of bleaching powder and distilling. The chlorine monoxide, contaminated with a little free chlorine, was prepared from dry chlorine and mercuric oxide as described in “ Roscoe and Schorlemmer.” VOL. LXXXI 4 R1298 MELLOR: THE UNION OF HYDROGEN AND CHLORINE. Time in minutes. 1 2 3 4 5 6 3 8 9 10 11 12 13 Efect of adding Hydrogen Hypochlorite.Index movements. Standard . 0 1 3 6 11* 10 - I - - - - HOCl about 1 mm. 0 0 1 2 4 8 9" - - - I - - Time in minutes. 1 2 3 4 5 6 7 8 9 10 11 12 13 Index movements. HOG1 5bou t 5 mm. ) The asterisk u * " indicates that the period of induction is over and that the velocity of the reaction is constant. Efeot cy? Adding Chlorine Monoxide. Time in minutes. 4 5 6 7 8 9 10 11 12 13 14 15 Index movements. Standard. c1,o ibout 1 mm.) - 1 3 10 18 23 21" - - - - - Time in minutes. 7 8 9 10 11 12 13 14 15 16 17 18 Index movements. Standsrd. c1,o rbout 5 mm.) Neither the presence of traces of hydrogen hypochlorite nor of chlor- ine monoxide appears to affect the rate of formation of hydrogen chloride very much, and no efect is produced o n j r s t exposure. It is assumed that if it were necessary for either chlorine monoxideVI.THE PERIOD OF TNDUCTION. 1290 or hydrogen hypochlorite to be formed before chemical action can take place, the period of induction would be abbreviated or annulled altogether when either of these substances is introduced into the system*: hydrogen I water vapour I chlorine. It may be objected (1) (‘nascent ” chlorine monoxide (or hydrogen hypochlorite) is more active, chemically, than when prepared in the usual way ; (2) since chlorine monoxide (or hydrogen hypochlorite) is very difficult to purify, impurities are certain to be present, consequently the accelerating influence of the intermediate compound is balanced, so t o speak, by the retarding influence of the impurity (compare Bunsen and Roscoe, Pld.Trans., 1857, 146, 390, et Sep.). But it must be re- membered that the induced mixture may be kept nearly 30 minutes without losing all its induced activity. This is not a characteristic of ‘‘ nascent ” activity. Again, since hydrogen is not directly concerned with the first stage of either cycle, C1, + H,O = C1,O + H,; or C1, + H20 = HOCl + HCI, the natural inference is that moist chlorine exposed to sunlight will exhibit a greater chemical activity towards hydrogen than chlorine not so treated. This is not the case. Still further, the presence of hydrogen along with the moist chlorine would, according to the mass law, drive back the formation of chlorine monoxide, and consequently this compound should be more easily formed in moist chlorine than in a mixture of moist chlorine and hydrogen.When actively combining hydrogen and chlorine gases, which have passed through the period of induction, are placed in darkness, chemical combination stops. If the gases are re-illuminated, the duration of the second period of induction is less than the first provided that the induced gases have not been more than hnlf-an-hour in darkness. Bunsen and Roscoe (Zoc. cit., p. 395) have also published other experiments which prove undoubtedly that there is a marked difference in the chemical activity of an insolated and of a non- insolated mixture of hydrogen and chlorine. This fact coupled with the experirtients recorded in this communication lead to the con- clusion that the presence of hydrogen as well as of moisture determines the greater chemical activity of the induced mixture of hydrogen arid chlorine gases.No compound formed by the interaction of water and chlorine alone will explain the indifference of insolated moist chlorine towards hydrogen; nor will the formation of any compound of hydrogen and * Jakowkin’s work appears t o show that minute quantities of hydrogen hypo- chlorite are normally present in the atmosphere above a solution of chlorine in water (Zcit. phpikak. Chenz , 1899, 29, 613),1300 MELLOR: THE UNION OF HYDROGEN AND CHLORINE. chlorine explain the part played by water in the reaction; the con- ductivity experiments of J. J. Thomson negative any dissociation or ionic hypothesis, and the law of mass action furnishes a satisfactory explanation of the period of induction provided an intermediate com- pound is postulated ; I therefore infer that ay an intermediate compound is formed a t all, it is a complex containing xC12,yH,0,xH2 (where x, y, x, are positive integers) which acts as the intermediate compound in Bunsen and Roscoe's chlorine-hydrogen actinorneter. Action of Eydrogen on Hydrogen Hypochlorite and om Chlorine Monoxide.According to Balard (Ann. Chim. Phys., 1834, [i], 57, 225), hydro- gen appears to exert no action on chlorine monoxide or on hydrogen hypochorite at the ordinary temperature." IT have confined hydrogen and nitrogen in separate eudiometers over dilute solutions of hydrogen hypochlorite for two days (diffuse daylight) at 15", but no chemical action could be detected. Similar experiments, in which the gases, confined over the aqueous hypo- chlorous acid, were heated at looo by means of a steam-jacket for 1-4 hours, gave negative results.Hydrogen hypochlorite in aqueous solution, however, is a t once attacked by nascent hydrogen from a zinc-copper couple, or sodium amalgam placed in the solution. I n the attempt to find if hydrogen attacks nascent hydrogen hypo- chlorite, sufficient carbon dioxide was passed into an aqueous solution of sodium hypochlorite to liberate all the available acid. The same amount of a mixture of hydrogen and carbon dioxide gases bubbled through a similar solution of hypochlorite made no difference to the amount of '' hypochlorite " obtained in each case. These experiments, therefore, do not support the view that eitber chlorine monoxide or hydrogen hypochlorite reacts with hydrogen during the second stage of cycles I or I1 respectively to form hydro- gen chloride as indicated in the equation C1,O + 2H2 = 2HCl + H,O ; or 2HOC1 + H, = 2HC1+ H20.I have yet t o discuss the explanation offered by the two dependent reactions suggested by the equation : * Compare also Cooke (Chem. News, 1888, 58, 103 ; from Glasgow Phil. Trans.) -k I desire to thank Mr. W. R. Anderson, B.Sc., for valuable assistance with the for the reducing action of hydrogen i n the presence of platinum. experiments on the chlorine oxides,DECOMPOSITION OF WATER VAPODR BY THE ELECTRIC SPARK. 1301 A similar cycle was indicated by Mrs. Fulhame, as far back as 1802, t o explain the essential part played by water on certain chemical reactions. Conclusions. 1. I f the reaction between hydrogen and chlorine in the presence of moisture is assumed to take place with the formation of an intermediate compound, the period of induction is a direct consequence of the law of mass action. 2. Since neither chlorine monoxide nor hydrogen bypochlorite abbreviates the period of induction, neither of these substances can take part, as intermediate compounds, in the reaction between hydrogen and chlorine. 3. Since chlorine acquires no appreciable chemical activity by exposure t o sunlight, the presence of hydrogen as well as of moisture determines the greater chemical activity of an induced mixture of hydrogen and chlorine gases. 4. If a n intermediate compound takes part in the reaction between hydrogen Fand chlorine in the presence of moisture, the most probable ‘( compound ” satisfying the required conditions contains xCl,,yH20,zH2, where x, 9, and x are positive integers. I desire to express my gratitude to Professor Dixon for his kind interest and advice during the course of this work. THE OWENS COLLEGE, M ANCHESTER.

ISSN:0368-1645    

DOI:10.1039/CT9028101292

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

DECOMPOSITION OF WATER VAPOUR BY THE ELECTRIC SPARK. 1301 CXXXIL-The Decomposition of Wateol Vapour by the Elect& Spark. By D. L. CHAPMAN and F. AUSTIN LIDBURY. THE hypotheses relating to the electrical aspect of chemical changes in solution have proved so fruitful in modern chemistry that it seems desirable that every effort should be made to extend them to the other states of matter, and in particular t o the gaseous state. The most convincing evidence for the ionic theory of solution is the explana- tion which it affords of phenomena, such as electrolysis, which admit of simultaneous electrical and chemical measurements being made, It is therefore unfortunate that our knowledge concerning the chemical changes which accompany the passage of an' electric spark through compound gases is not at present sufficiently wide to admit VOL.LXXXI. 4 s1302 CHAPMAN AND LIDBURY : THE DECOMPOSITION OF of its being accepted as evidence for any theory correhting the chetnical and electrical aspects of the phenomena. It was with the object of extending our knowledge in this direction that the present investigation was undertaken. Several researches on the passage of electricity through compound gases have shown that, not only are the compounds decomposed, but an actual separation of the constituents occurs, and the attempts which have been made to compare the separation with the quantity of electricity which passes through the gas cannot be said to have excluded the possibility of a law connecting them similar t o Faraday’s law for solutions. Perrot (Ann.Chim. P?iys., 1861, [iii], 61, 161) has shown that when an electric spark passes through steam the decomposition which occurs is not limited to the electrodes, but takes place throughout the length of the spark; that it varies with the length of the spark, and can, under favourable conditions, exceed by twenty times the decomposition in a voltameter placed in the same circuit, so that i f any relation is to be discovered between the gases liberated and the current passed, only the excesses of oxygen and hydrogen which make their appearance at the anode and cathode respectively must be considered. Experiments were performed by Perrot for the purpose of testing this point. H e found that the gases liberated at the anode contained an excess of oxygen, and those at the cathode an excess of hydrogen, their amounts being equivalent to the copper deposited in a voltameter in the same circuit.The experiments proved that the current is conveyed through water vapour in the same manner as through water. Perrot’s experiments were repeated by J. J. Thomson (“ Recent Re- searches in Electricity and Magnetism,’’ Appendix), who found that the separation was not independent of the length of the spark. With a short spark, the excesses of oxygen and hydrogen collected a t the two electrodes were equal to the oxygen and hydrogen collected in a volta- meter in the same circuit, The hydrogen, however, appeared at the positive electrode instead of, as ‘in ordinary electrolysis, at the negative. With medium sparks, the separation of the oxygen and hydrogen in the steam was greater than in the water voltameter.The hydrogen mas still liberated at the positive electrode as with the short sparks. With long sparks (provided they were not too long otherwise the results became irregular), the hydrogen appeared at the same electrode both in the voltameter and in the spark, their volumes being approximately equal. Thomson regards the separation of oxygen and hydrogen, which results from the passage of a spark through water vapour, as due t o the movement of charged oxygen to one electrode, and oppositely charged hydrogen to the other electrode, the difference noticed with the short and long sparks being due to the fact that the hydrogen has *WATER VAPOUR BY THE ELECTRIC SPARK, 1303 a negative charge when the discharge resembles an arc, whereas it is positively charged when the discharge is long and takes place as a series of separate sparks through the unmodified vapour.E. Wiedemann and G. C. Schmidt (Annm. Phys. Chem., 1897, [iii], 61, 737) concluded after a series of experiments on hydrogen chloride and the vapours of the halogen compounds of mercury that Faraday’s law does not apply to gases, since the separated halogen was much less in amount than that required by the law. Besides the quantitative investigations mentioned above, spectro- scopic evidence of the separation of the constituents of compound gases by the passage through them of the electric spark has been obtained by several investigators. In our experiments, a discharge from an induction coil was passed be- tween the anode, A , and cathode, C, of a vacuum tube containing water vnpour. The supply of water vapour was continually renewed by with- drawing it, together with the gases prdduced, in approximately equal quantities, through the tubes E and P situated near the electrodes, and FIG.1. F. allowing a fresh quantity to enter through D. The quantity of elec- tricity which passed between A and C was measured by means of a voltameter placed in the same circuit. The gases withdrawn from E and P were analysed. The rate at which the water vapour passed through the tuhe could be regulated. The gases withdrawn from E and P consisted of mixtures in dif- ferent proportions of oxygen and hydrogen. They were separately collected, exploded to remove the excess of electrolytic gas, and the residue, consisting of oxygen or hydrogen, analysed.The conditions of the experiment were altered in two particulars, (1) the rate at which the water vapour passed through the tube was varied, (2) the position of the tube D at which i t entered was altered. When the stream of water vapour is slow, the separation of oxygen and hydrogen in the tube is smaII, but ceteris paribus increases rapidly as the stream becomes faster, so that in Grder to obtain the maximum effect a rapid and continuous current of water vapour must be passed through the tube. 4 s 21304 CHAPMAN AND LIDBURY: THE DECOMPOSITION OF The result of varying the position of the tube D is very interesting. When it was near the cathode, the gases collected at P contained an excess of hydrogen, as in ordinary electrolysis, but this excess of hydrogen was found in several cases to be five or six times as great as that collected in the voltameter.The fact that this large difference can exist in the volume of hydrogen separated by the same current in water vapour and in liquid water points to the conclusion that the separation in the vapour cannot be entirely due to electrolysis." t The large difference in the hydrogen obtained from the two sources was, however, not maintained when the water vapour entered the tube at a greater distance from the cathode. When the tube D was midway between the anode and cathode, the excess of hydrogen passing out of the cathode exit tube was not more than double that collected in the voltameter, and the ratio continued to decrease as the tube D was moved nearer the anode.If the inlet tube is brought very near to the anode, the electrodes a t which the excesses of oxygen and hydrogen appear are reversed, that is, the oxygen appears at the cathode and the hydrogen at the anode, a result which recalls that obtained by J. J. Thomson with short sparks. Now during all the experiments an effort was made to maintain a uniform discharge, so that the reversal of the poles a t which the oxygen and hydrogen make their appearance is not entirely due to a change in the character of the discharge. The position of the tube D through which the vxpour enters has, obviously, a marked influence on the composition of the gases withdrawn at E and F. With these facts before us, we can draw the following conclusions, 1.That when a series of electric sparks is passed through water vapour, decomposition of the water and recombination of the oxygen and hydrogen take place simultaneously until equilibrium is estab- lished. 2. The oxygen and hydrogen produced by the decomposition tend to separate and take up different positions in the tube. This separation does not proceed to an unlimited extent, and is prevented from doing so by a simultaneous mixing due to convection currents and t o diffu- sion. The rate of mixing, of course, increases as the variation in the composition of the gases in different parts of the tube becomes greater, 3. The arrangement of the products of decomposition does not take place in such a manner that the hydrogen appears a t one pole and the oxygen at the other, but hydrogen separates at both the anode and cathode, the oxygen being driven to the middle of the spark gap.* The word electrolysis is used here and elsewhere to denote the process of t Disregarding, of course, the exceedingly improbable hypothesis that the ions are conduction of electricity by the movement of charged ions. highly polymerised molecules.WATER VAPOUR BY THE ELECTRIC SPARK. 1305 It will be seen that conclusions 1 and 2 account for the fact that a more rapid stream of water vapour causes a greater separation of oxygen and hydrogen, and that with a slow current very little separation can be observed, for with a slow stream of vapour the gases are not driven out of the tube immediately they are separated, and they are thus given a greater chance of remixing.In connection with this point, it is perhaps well to observe that the small separation of hydrogen and chlorine obtained by Wiedemann and Schmidt with hydrogen chloride was probably due to the stream of gas being too slow to prevent a rapid mixing of the separated gases in the vacuum tube itself. Conclusion 3 accounts for the nature of the results obtained by FIG. 2. c- t.. i varying the position of the tube D. For suppose that the tendency of the oxygen and hydrogen to collect in different parts of the tube is represented by the curve B 0 Y P E , where the points A and C correspond to the anode and cathode respectively, and an excess of hydrogen per unit length is measured by a line drawn upwards from A to the curve and a n excess of oxygen by a line drawn downwards. These lines represent equivalents of oxygen and hydrogen respectively, so that the area PE C together with the area A 0 D must equal the area 0 PF. If the water vapour enters at the point F, the stream which passes in the direction FC will drive out the hydrogen repre- sented by the area P E C, whereas the stream of water vapour which passes in the direction P A will drive out an equivalent amount of oxygen.On the other hand, if the vapour enters the tube at the1306 CHAPMAN AND LIDBURY: THE DECOMPOSITION op point 0, hydrogen will be driven towards the anode and oxygen towards the cathode, that is, there will be a reversal of the electrodes at which the oxygen and hydrogen make their appearance, If a point X be chosen, such that the area A 0 D is equal to the area 0 X P, and the area X Y P to the area P E C, then on allowing the water vapour to enter the tube at the point X we ought to find, on collecting the gases at the anode and cathode, that no separation had taken place.The point X is, however, not absolutely fixed in position, and moves backwards and forwards during the course of the experiment, so that if the inlet tube is near to this point, the pole at which the excess of hydrogen appears is continually reversed, but at the end of an experiment lasting for a long time the separation produced by the spark is only a small fraction of the gases collected in the voltameter. We are not prepared a t present to offer any theory to account for the dhtribution of oxygen and hydrogen in a tube containing water vapour subjected to the action of a series of sparks from an induction coil, as we believe that, with the exceedingly limited number of facts at our disposal, more than one plausible hypothesis could be constructed.Our experiments, however, prove decidedly that the separation of the constituent elements of water is not entirely due to a process of electrolysis, because in that case oxygen should appear a t one electrode and hydrogen at the other, whereas hydrogen collects at both elec- trodes ; and, secondly, their quantities should not exceed the quantities of oxygen and hydrogen collected in a voltameter through which the same current passes, EXPERIMENTAL. The arrangement of the apparatus used is indicated by the accom- panying diagram.The flask A contains water which is continually evaporating during the experiment. The vapour thus produced passes up the tube C into the vacuum tube, 23 3'. On entering the vacuum tube, the current of water vapour divides, part going towards E and the other part towards F. The gases produced on each side of the inlet tube by the passage of the spark are driven forward by the water vapour along the tubes G and into the condensers M and N, which are surrounded by freezing mixtures. The water vapour condenses in N a n d N, and the gases which are left behind are drawn out by the continuous Sprengel pumps P and Q, The pumps were con- structed without rubber in order t o avoid as far as possible the presence of sulphur and organic matter. The spark is produced by the induction coil X." The quantity of electricity passing in one * The induction coil was provided with a large condenser, and &n air gap was always introduced into tb5 circuit.WATER VAPOUR BY THE ELECTRIC SPARK.1307 direction is measured by the gases collected in the voltameter Y . The gases produced in the spark are collected and measured in the apparatus Z a n d in a precisely similar apparatus (not shown i n the diagram) attached to the other pump. The voltameter 4 contained dilute potash solution. At the close of an experiment, the gases which it contained were measured by turning off the tap a, drying FIG. 3. c the tube below the tap, and weighing the voltameter with the enclosed gases.Two other weighings are obtained, firstly, with the gas in one limb displaced by potash solution, and secondly, with both limbs full of potash solution. From the weight of. potash displaced in both limbs, it is obvious that the volumes both of oxygen and hydrogen can be calculated when the necessary corrections for1308 CHAPMAN AND LIDBURY : THE DECOMPOSITION OF density of potash solution, barometric pressure, heights of columns ot potash, temperature, and vapour tension have been made. The volumes of oxygen and hydrogen separated in the spark are measured by the weights of mercury displaced in the apparatus 2. During the experiment, the gas is collected in the compartment y. When this is full, the taps a and p are opened and the gas passes into the compartment 6, where the admixed electrolytic gas is removed by explosion with a and /3 closed.This operation is repeated until a suEcient quantity of gas has been collected. The apparatus is weighed with the taps u and p closed, and the vessel y and the tube below the tap /3 empty. All necessary measurements of columns of mercury are made in a mercury trough with a scale and telescope. The gases can, with the aid of this apparatus, be measured directly and also analysed by explosion. Every precaution must be taken to exclude organic matter from the apparatus, as the oxygen produced by the spark appears to be in a particularly active form. Method of Conducting an Experiment .-Distilled water is drawn into the flask A through the tube B by working the Sprengel pumps, and B is then closed before the blow-pipe.The air is next removed from the apparatus by setting the pumps in action. This operation is accelerated by surrounding M and N with freezing mixtures, which pro- duce a rapid current of water vapour through the apparatus towards the pumps. As soon as M and N are full of water, the freezing mixtures are removed and the water distilled back into the flask A by sur- rounding it with ice. After repeating this process several times, the experiment is started. A series of sparks is sent from an induction coil through the voltameter Pand the vacuum tube E 3! The flask A is placed in a water-bath which is kept approximately a t a temperature of 1 5 O , and Mand N are surrounded with freezing mixtures of ice and salt. The pumps are kept in continuous action during the whole course of the experiment.The gases which collect in 2 must be exploded from time to time as previously described. A fresh vacuum tube must be made and fused on to the apparatus whenever it is desired to vary the conditions. In several experiments made at the beginning of the investigation, i t was noticed that the volume OF the oxygen collected at the anode was less than half that of the hydrogen collected a t the cathode, pointing to a disappearance of oxygen. This we believe was due to . the formation of ozone in the spark, which subsequently acted on the mercury of the pumps, a supposition which is rendered more probable by the fact that this source of error may be considerably reduced by introducing silver gauze into the horizontal tubes leading The absence of rubber is imperative.WATER VAFOUR BY THE ELECTRIC SPARK.1309 - - - - 1'36 C.C. from the condensers to the pumps, and warming the gauze during the experiment. This precaution was taken in all the later experiments. - 2.32 ,) 0'837 ,) 3-80 ,, 1.95 ,, The Remits Obtained. T. In a large number of earlier experiments, the water vapour was conducted into the vacuum tube at a point near to the middle of the spark, and the current of water vapour through the tube was slow owing to the fact that the temperature of the condensers was only three or four degrees lower than that of the reservoir. Under these circumstances, the amount of hydrogen coming from the cathode of the spark varied between one-half and :one-fourth of the volume of the same gas collected at the cathode of the voltameter. One example will suffice to illustrate this : Hydrogen from spark =3.1 C.C. Hydrogen from voltameter = 6.6 ,, T I .Expr&nents with the Inlet Tube near the Niddle of the 8padc Gap-The condensers were made larger and kept a t a lower tempera- ture by means of a freezing mixture of ice and salt. The water vapour entered the tube near the middle of the spark. The ratio of hydrogen from the spark to hydrogen from the voltameter varied from 1 to 2 : Number of experiment. H, from voltameter. A, ______ 1-088 C.C. 1.108 ,, 1.338 ), 0'889 ), 0.696 ), 1.76 ,, 1-57 ,) 1.084 C.C. 0.952 ,, 1.133 ) ) 1.982 ), 3.05 ,) - - ~ B. I A. B. 1'163 C.C. 1.08 ) ) 1.155 ,, 2'14 ), 0-827 ,) 3.63 ,, 1.76 ,, The numbers in column A were obtained by direct measurement, and those in B by explosion. It will be observed that, in spite of the silver gauze, the oxygen was always less than half the hydrogen, and that the hydrogen was mixed with a small proportion of inert gas.111. Experiments with the Inlet Tube near to the Cathode.-The length of the spark varied from about 100 to 110 mm., and the inlet1310 DECOMPOSITION OF WATER VAPOUR BY THE ELECTRIC SPARK. Number of experiment. tube was about 10 mm. from the bulb containing the cathode. The electrodes were made of thick platinum wire and varied in length from 25 to.30 mm. The tube through which the spark passed was 8 mm. in diameter, and the inlet tube 5 mm. : H, from - ~. voltameter. A. ~ .. _~ I 1 2 x 0, from anode. 1 2 3 Sum 1'23 C.C. 4-22 C.C. 0'992 ,, 5.74 ,, 0'376 ,, 2'60 ,, 2.59.8 ,, 12-56 ,, 4-19 C.C. 5.95 ,, 2.75 ,, 12.89 ,) Hydrogen from spark Hydrogen from voltameter _ _ ~ 4-15 C.C. - - - - -- B. 1.545 C.C. 1,,,I,I 0.33 C.C. _ _ ~ H, froin cathode. 0.86 C.C. 0'78 C.C. A. I B. -I - - Eg = 4.9 (nearly). 2'598 IV. Experiments with the Inlet Tube near to the Anode.-These experiments were much more difficult to perform on amount of the residues of oxygen and hydrogen collected at the two pumps being much smaller than in the previous series. I n three experiments, we showed that the hydrogen appeared at the anode and the oxygen at the cathode by applying qualitative tests, and in one case a complete analysis of the gases was made with the following results : 2 x 0, from cathode. H, from voltameter. B. H, from anode. A. 1 B. The percentage error due to the absorption of the oxygen by the mercury of the pumps and the contamination of the hydrogen by inert gases becomes more pronounced, since the actual quantities of gases obtained in the same time is much less than in all the previous experiments. Concluaim. The separation of oxygen and hydrogen produced by the passage of an electric spark through water vapour cannot receive a complete explanation from a hypothesis based exclusively on the unmodified theory of electrolysis of liquids. THE OWENS COLLEGE, MANCHESTER.

ISSN:0368-1645    

DOI:10.1039/CT9028101301

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

DERIVATIVES OF DIBENZOYLME3ITYLENE. 1311 CXXXII1.-Derivatives of Dibenxoylrnesitylene. By WILLIAM HOBSON MILLS, Fellow of Jesus College, Cambridge, and THOMAS HILL EASTERFIELD. THE synthetical production of polycyclic hydrocarbons which contain more than four rings has hitherto been but rarely effected. For this reason, it seemed desirable to undertake a further study of the substance dibenzoylmsitylene, CH3 C6H5*CO(\,CO*C H prepared by Louise in 1885 (Ann. Chim. Phys., [vi], 6, 234) ; more particularly to work out a method for its preparation which would enable it to be obtained in quantity, and to study the acids which would be derived from it by the oxidation of two of its methyl groups to carboxyl. For just as o-benzoylbenzoic acid is condensible by phosphoric oxide (Behr and van Dorp, Ber., 1874, 7, 578) or concen- trated sulphuric acid (Liebermann, Ber., 1874, 7, 805 ; Perkin, Trans., 1891, 59,1012) to anthraquinone, so was i t to be expected t h a t the two dibenzoyluvitic acids.: CH,”GH, ’’ would, under the influence of dehydrating agents, be convertible into quinones of the formulae : respectively, from which the corresponding hydrocarbon might be prepared by reduction. The present paper deals mainly with the preparation of dibenzoyl- poesitylene and with the acids obtained from if by oxidation. An1312 MILLS AND EASTERFIELD : account of the action of dehydrating agents on the latter is reserved for a later communication. Louise (Eoc. cit.) prepared dibenzoylmesitylene by treating a mixture of mesitylene and benzoyl chloride with a very small quantity of aluminium chloride a t a high temperature. The high temperature, however, and its attendant disadvantages may be avoided, provided that the benzoyl chloride is allowed to act on the mesitylene in warm carbon disulphide solution in the presence OF a large excess of aluminium chloride, the procedure thus closely corresponding to that worked out by Victor Meyer (Ber., 1896,29, 846, 1413) for the produc- tion of the diacetyl derivatives of durene and mesitylene.I n this mmner, the preparation can be carried out on a comparatively large scale, and excellent yields may be obtained. Incidentally, the action of reducing agents on the ketone was studied. Zinc and potash acting on an alcoholic solution of the ketone reduce it to dihydroxydibenzylmesitylene, CH.9 a substance not yet obtained in a crystalline condition. When boiled with hydriodic acid (b. p. 127') and yellow phosphorus, dihydroxydibenzylmeaitylene is converted i n t i a beautifully crystalline compound melting at 89O. ' I t s composition and vapour density, taken together with its mode of formation, show conclusively that this substance must be dibernxylmesitylene : Louise (Ann. Chim. Phys., 1885, [vi], 6, 197), however, has described as dibenzylmesitylene a substance melting at 1 31°, which he obtained directly from mesitylene by the action of benzyl chloride and aluminium chloride. Since tribenzylmesitylene would have a composition so similar to that of dibenzylmesitylene that analysis alone could not distinguish between them, it seems not impossible that the substance obtained by Louise may be tribenzylmesitylene. It was, however, in the oxidation of the ketone that our interest was chiefly centred.After various preliminary experiments, it was found that dilute nitric acid was the only suitable oxidising agent.DERIVATIVES OF DIBENZOYLMESITYLENE. 1313 When heated with dilute nitric acid in sealed tubes at 140' for 14 hours, dibenzoylmesitylene is converted into a mixture of acids, consisting mainly of the two desired clibenzoyluvitic acids. CH3 C,H~*CO/\CO* C,H, UO,H()CO,H r. It was to be expected that would be effected by treating CO,H C,H, CO/'\CO*C,H, C0,H(/CH3 11. the separation of two such substances the mixture with methyl alcohol and hydrogen chloride, when the acid of formula I would yield a normal ester, whilst that of formula 11, in accordance with Victor Meyer's esterification rule, would give an acid ester only.As a matter of fact, however, both acids were by this treatment rapidly converted into their dimethyl esters. Further investigation showed that these acids were really the two dibenzoyluvitic acids. The interesting fact was thus established that the benzoyl group as an ortho-substituent forms an exception to Victor Illeyer's esterification rule." None the less, this treatment led to a method of separating the two acids, for whilst the methyl ester of one is readily soluble in methyl alcohol, that of the other is so sparingly soluble that it separates out almost completely from the esterificntion mixti ire. By saponifying the two esters thus obtained, there resulted the corresponding dibenzoyluvitic acids, that from the sparingly soluble ester melting at 262O, that from the other a t 213'.There was, however, still no clue as to which of the two possible formuls belonged to which acid. To gain some evidence on this point, their rates of esterification were compared, but since the acid with the sparingly soluble ester was found to be the more rapidly esterifiable, no definite conclusion could be drawn, i t being impossible to be certain that the removal of the ester from the sphere of action through its insolubility did not accelerate its rate of formation relatively to that of the ester of the other acid-the two acids could not be esterified under comparable conditions.Another method suggested itself which promised to yield more definite results. This was to prepare the two dibenzoylmesitylenic acids which would result from the oxidation of one only of the three methyl groups of dibenzoylmesitylene : * Some time after this had been observed, an account of the similar behaviour of 3 : 6-dichlorobenzoylbenzoic acid was published by Graebe (Ber., 1900, 33, 2026).1314 MILLS AND EASTERFIELD : CH3 CO,H c6H5*cd\co C6H, c,H~~co/'\co- C,H, CO,HI/CH, CH,j)CH, 111, IV. Then, whereas the unsymmetrical acid (111) on f urthei. oxidation should yield a mixture of the two dibenzoyluvitic acids, the sym- metrical acid (IT) should yield only one of these, namely, that of the formula I1 : CO,H CO,H()CH, Y and thus would be fixed the constitution of all four acids in question.Although dibenzoylmesitylene is not attacked by dilute nitric acid when boiled with it under ordinary conditions, it is readily oxidised when the boiling point of the diluted acid is raised to 125' by the addition of large quantities of potassium and sodium nitrates, and it then yields a mixture of all the five acids which can result from it by the successive conversion of its three methyl groups into carboxyl. Of this mixture, one of the required dibenzoylmesitylenic acids (of melt- ing point 174') forms by far the largest constituent. The other acids are present in relatively small quantity, and the isolation of the second dibenzoylmesitylenic acid was a matter of some difficulty ; it was finally effected by crystallising the mixture of acids from ethyl acetate and from alcohol. The two dibenzoylmesitylenic acids thus obtained were then oxidised in alkaline solution with potassium permanganate, with the result that that of melting point 1'74' yielded a mixture of both dibenzoyluvitic acids, whilst that of meiting point 2 2 2 O under the same conditions yielded only the dibenzoyluvitic acid melting at 213'.The constitution of the five acids resulting from the oxidation of dibenzoylmesitylene was thus settled. The dibeqzoylmesitylenic acid of melting point 1 7 4 O , which, on oxidation, gives the two dibenzoyluvitic acids, must be the unsym- metrical acid of formula 111 : C,H,* CO/\CO*C,H, CH3 Y' 111. ' x C,H,*CO/\CO-C,H~ CO,H?)CH, CH CO,H c6H,*CO/\CO*C,H, c H 'C*IO/\CO*C,H, CO,H(/CO,H 6 0 , H u C H 3 I.11.DERIVATIVES OF DIBENZOY LMESITY LENE. 1315 The dibenzoylmesitybnic acid of melting point 222O, which, on oxidation, gives only one dibenzoyluvitic acid, must be the symmetrical acid of formula IV : C0,H CO,H C,K,.CO/\CO*C~N, \/ CO,H/ 'CH, IV. I1 It therefore follows that dibenzoyluvitic acid melting a t 213' is the unsymmetrical acid (formula II), and that melting at 262' is the symmetrical compound (formula I). EXPERIMENTAL. Preparation of Bi benxoylmesitytene, One hundred grams of aluminium chloride are rapidly pounded and covered with 250 C.C. of dry carbon disulphide. Eighty-five grams of benzoyl chloride are then added, and while the mixture is gently boiled under a reflux apparatus, 17 grams of mesitylene are slowly dropped in from a dropping funnel.The liquid a t once assumes a brownish-red colo u r . After boiling for 14 hours (by which time the aluminium chloride has almost completely dissolved), the mixture is allowed to cool and then decomposed by pouring on to lfr kilos. of pounded ice. After treating with concentrated hydrochloric acid t o dissolve the precipitated alumina, the carbon disulphide, containing the ketone and the excess of benzoyl chloride in solution, is separated, hydrochloric acid added, and the mixture heated in a current of steam-the heating must be continued for a t least half-anbhour after the carbon disulphide has been driven over to ensure complete decomposition of the benzoyl chloride, After cooling somewhat, the crude ketone sets t o a solid brown mass a t the bottom of the flask, from which the warm dilute acid, containing much benzoic acid in sol~ution, can be poured away.Dilut,e caustic soda is then added and the mixture again heated with steam just long enough t o ensure thorough agitation of the melted ketone with the hot soda. After cooling, the crude ketone is dissolved in hot alcohol, from which i t crystallises in somewhat pinkish plates. When recrystallised from alcohol, it is sufficiently pure for use in further operations. The yield is about '70 per cent. of the theoretical, but for the success of the preparation it is absolutely essential t h a t all the material be of the very best quality. To obtain the ketone perfectly pure, it must be distilled in a vacuum.1316 MILLS AND EASTERFIFXD : It boils at 275-285' under 19 mm.pressure. The resinous mass thus obtained is crystallised from light petroleum and then from alcohol, and forms beautiful, white plates which melt at 117'. On analysis : 0.1748 gave 0.5372 GO, and 0.0960 H,O. Dibenzoylmesitylene also crystallises well from carbon disulphide or In ether, benzene, or chloroform, i t is extremely C = 83.8 ; H = 6-1. C,,H,,O, requires C = 84.1 ; H = 6.1 per cent. glacial acetic acid, soluble. To Louise's account of its properties, there is nothing to add. Oxidation of Dibenxoylmesitylene. The ketone is boiled in quantities of 20 grams with 40 C.C. of nitric acid, sp. gr. 1.5, diluted with 160 C.C. of water to which are added 240 grams each OF potassium and sodium nitrates. The boiling is continued for 6 hours, the temperature assumed by the mixture being 1 2 5 O .When cold, the mixture is extracted with ether, the ethereal solution washed free from nitric acid by careful treatment with dilute caustic soda, and finally with water ; the acids formed are then removed from unaltered ketone and nitro-derivatives by shaking with dilute sodium carbonate solution. The resulting solution is just neutralised with hydrochloric acid, the carbon dioxide expelled by gently warming under reduced pressure, and excess of calcium chloride solution then added. A considerable quantity of a yellowish-white, gummy, calcium salt is then precipitated, which, on vigorous stirring, ad heres completely to the sides of the vessel, so that the clear mother liquor can readily be poured away.The latter contains the soluble calcium salts of the two dibenzoyluvitic acids together with some dibenzoyltrimesic acid. It is best worked up together with the oxidation product of as-dibenzoyl- mesitylenic acid. The mixture of-dibenzoylmesitylenic acids is isolated from the gummy calcium salt by shaking with hydrochloric acid and ether. The residuo from the ether is fractionally crystallised from ethyl acetate, In this way, from 320 grams of dibenzoylmesit,ylene, 5 grams of an acid melting at 219' were obtained. This is symmetrical dibenaoyl- mesitylenic acid. The acid contained in the mother liquors was obtained in crystalline form by evaporating off the ethyl acetate and allowing the residues to crystallise from glacial acetic acid. Unsymmct&a I dibenzoylmesitylenic acid separates in a finely crystalline condition, but crystallisation takes pIace remarkably slowly, separation not being complete until after the lapse of several days..DERIVATIVES OF DIBENZOY LMESITYLENE. 1317 as-Dibenxoylmsitylsnic Acid, C,H,-CO CO-C,H, . COP, GL3 After two or three recrystallisations from glacial acetic acid and then from alcohol, the pure acid was obtained as a white, crystalline powder melting at 174-1 75". On analysis : 0.1242 gave 0.3515 CO, and 0.0556 H,O. C24H1804 requires C: = 77-09 ; H = 5.03 per cent. The acid dissolves with great readiness in ether, ethyl acetate, acetone, chloroform, or carbon disulphide ; it is less soluble in alcohol, glacial acetic acid, or benzene, whilst in water or light petroleum it is almost insoluble.The sodium salt of the acid crystallises in silky needles from a strong solution of the acid in sodium carbonate ; it can be purified by recrystallisation from a small quantity of water and is anhydrous : C=77.12; H=4*98. 0.2690 gave 0.0516 Na,SO,. The calcium salt is obtained, as already stated, as a transparent, gummy mass by precipitating a solution of the sodium salt with calcium chloride. It is soluble in alcohol and, to some extent, in ether. The barium, zinc, lead, copper, silver, and ferric salts are precipitated on treating a solu- tion of the ammonium salt with solutions of the salts of these metals. Methyl as-Dibenxoylmesitylnate.-A solution of the acid in methyl alcohol is saturated with hydrogen chloride and then boiled for 2 hours in a slow current of the gas.The ester is separated by dilution with water and extraction with ether in the usual way. The residue from the dried ethereal solution, on crystallisstion from alcohol, deposits the ester in radially striated masses. After repeated crystallisation from alcohol, it melts a t 125-126". Na = 6.20. C,,HI70,Na requires N = 6.05 per cent. The magnesium salt resembles the calcium salt. On analysis : 0.1192 gave 0.3377 CO, and 0,0560 H,O. The ester is readily soluble in the common organic solvents with C = 77.26 ; H = 5.22. C,4€T,o0, requires C = 77.42 ; H = 5.37 per cent. the exception of light petroleum and cold methyl or ethyl alcohol. VOL. LXXXI. . 4 T1318 MILLS AND EASTERFIELD : The substance obtained by fractionally crystallising the acid obtained from the gummy calcium salt from ethyl acetate was further repeatedly recrptallised from alcohol and then from glacial acetic acid.The product melted apparently constantly at 220°, but in a series of con- cordant analyses the carbon was found almost 1 per cent. too low. Bince the amount of substance was becoming too small for complete purification in this way, i t was dissolved in a solution of sodium car- bonate and allowed to crystallise. The sparingly soluble sodium salt separated out as a beautiful mass of somewhat thick needles. It was recrystallised from a solution of sodium carbonate, in which it seemed to be distinctly less soluble than in water. The acid, separated from the recrystallised salt and crystallised from methyl alcohol, melted at 221--222', and now gave, on analysis, results in satisfactory accord with those required for the formula C23H180.4 : 0.1464 gave 0.4127 CO, and 0.0673 H,O.C23H,804 requires C E 77.1 ; H = 5.0 per cent. The acid crystallises best from ethyl or methyl alcohol. It can also be recrystallised from ethyl acetate or glacial acetic acid and is fairly soluble in ether. A solution of the sodium salt gives sparingly soluble, amorphous precipitates with the soluble salts of silver, copper, lead, and iron. The magnesium, calcium, barium, and zinc salts separate slowly, in crystalline form, on adding a solution of a salt of the respective metal to a solution of the sodium salt of the acid, C=76.9 ; H=5-1. The Relative Rates of Esterificcction of the Two Di6enxoyZmesityZenic Acids.As it seemed of some interest to gain an idea as to the amount of obstruction offered by the benzoyl groups to esterification, an attempt was made to compare the rates of esterification of the two dibenzoyl- mesitylenic acids under comparable conditions. Unfortunately, the experiment was marred by the sparing solubility of the symmetrical acid in methyl alcohol, a portion having crystallised out during the esterification, but the result, nevertheless, served to show that diortho-substitution by two benzoyl groups produces aDERIVATIVES OF DIBENZOYLMESITYLENE. 1319 retardation of the rate of esterification, which, although quite distinctly marked, is yet very small in comparison with that produced by such groups as CH,, C1, or NO,. The experiment was carried out a t the ordinary temperature, with sulphuric acid as catalyser in place of the much less convenient hydro- chloric acid.0.5 gram of each acid was dissolved in 20 C.C. of methyl alcohol, to each 4 C.C. of concentrated sulphuric acid were added slowly with cooling, and the mixtures were then allowed t o stand side by side for 16 hours. It was found that the amount of symmetrical acid which had crys- tallised out was 0.1 gram. This was filtered off and the esters were separated by dilution with water and extraction with ether in the usual way and weighed after removal of the ether. The unesterified acids were also similarly isolated, and weighed as a check on the result. The yields were : s-Acid. as-Acid. Ester ..................... 0.15 0.24 Acid ........................0.25 0.28 Acid cryst. during expt. 0.1 - H. Goldschmidt has shown (Ber., 1895, 28, 3218) that for esterifi- cation in thia way in the presence of a large excess of alcohol, the formula for the unimolecular reaction, k = tlog---, l a a - x is applicable. This gives for the esterification velocity of the 8-acid referred to that of the as-acid as 1 : 0.76 or 1 to 058, according as it is assumed that the quantity of acid which crystallised out was absent from or present in the reaction mixture during the whole period of reaction. The actual number will thus probably lie in the neighbour- hood of 0.65. Oxiahtion of s-Dibenxoylmesitytenic Acid. One gram of the acid was dissolved in 20 C.C. of hot dilute sodium carbonate and added to a molecular proportion of potassium perman- ganate (0.88 gram) dissolved in 10 C.C.of boiling water. The mixture was kept hot in the water-bath and became decolorised in about half- an-hour , The manganese dioxide was filtered off, the filtrate concentrated to 6-8 c.c., and allowed to stand overnight in order to allow the unoxidised acid to separate in the form of its sparingly soluble sodium salt. The small quantity of this which crgstallised out was filtered off and the filtrate was acidified and extracted with ether. The 4 T 21320 MILLS AND EASTERFIELD : residue from the ethereal solution was dissolved in 15 C.C. of methyl alcohol and treated with hydrogen chloride on the water-bath. No separation of the sparingly soluble ester of s-dibenzoyluvitic acid took place.The ester formed was isolated and crystallised several times from methyl alcohol. I n this way could be isolated a less soluble fraction melting sharply at 187'. This is the methyl estei- of dibenxoyltrimesic acid. The more soluble fractions were saponified by treating for 2 hours in the cold with methyl alcoholic potash. The mixture was diluted, the alcohol boiled away, and the solution acidified with dilute sulphuric acid and extracted with ether. The ethereal solution was concentrated to a small volume and the acid allowed to crystallise. It already melted at 21 lo. It was recrystallised from glacial acetic acid and found to be identical with the as-dibenzoyluvitic acid obtained by oxidising as-di- benzoylmesitylenic acid-in particular the melting point of a mixture cf the two preparations was the same as that of either separately.Hence the oxidation of the dibenzoylmesitylenic acid melting at 222' by a molecular proportion of potassium permanganate results in the production of only one dibenzoyluvitic acid (the as-acid) together with a small quantity of dibenzoyltrimesic acid. Oxidation of as-Dibenxoylmesit ylenic Acid. A boiling solution of 10 grams of the acid in 100 C.C. of dilute sodium carbonate solution was poured into a boiling solution of 8.8 grams of potassium permanganate in 100 C.C. of water and the mix- ture kept hot in the water-bath until decolorisation had taken place. This required about half-an-hour. After removal of the manganese dioxide, the filtrate was neutralised, concentrated somewhat, and mixed with a solution of calcium chloride to precipitate the unoxidised acid in the form of its gummy calcium salt.The filtrate was acidified, extracted with ether, and the ethereal solution dried by shaking for a short time with fused calcium chloride and then evaporated. The residue, dissolved in methyl alcohol, was treated with hydrogen chloride on the water-bath for two m three hours after saturation had taken place, The sparingly soluble ester of 8-dibenzyluvitic acid soon began to separate from this hot solution. After standing overnight, the crystalline ester was filtered off and washed with methyl alcohol. The more soluble ester of as-dibenzoyl- uvitic acid was isolated from the mother liquor by dilution with water, extraction with ether, and treatment with sodium carbonate in the usual way.DERIVATIVES OF DIBENZOYLMESITYLENE.1321 In one experiment, 10 grams of as-dibenzoylmesitylenic acid yielded 4.85 grams of sparingly soluble ester, 3-35 grams of soluble ester, and 1 -43 grams of unesterified acid. Methyl s-dibenxoyluuifate, (C6H5*CO),C,H(CH3)(C02*CH3)2.-The sparingly soluble substance obtained by esterification of the above- mentioned oxidation product consists mainly of this ester, but it con- tains also some of the ester of dibenzoyltrimesic acid, which is formed, to a limited extent, by the further oxidation of the two dibenzoyluvitic acids. It may be obtained free from the latter by recrystallisation successively from methyl alcohol, chloroform, and methyl alcohol again, and then forms small, white needles melting at 252'.It is very sparingly soluble in alcohol or ether (100 C.C. of alcohol dissolves 0.03 gram at the ordinary temperature), but dissolves much more readily in chloroform, and with the greatest ease in the other common organic solvents, excepting light petroleum. On analysis : 0.1259 gave 0.3328 CO, and 0.0547 H20. s-DibenxoyEuvitic Acid.-Finely divided methyl dibenzoyluvitate is suspended in hot alcohol and treated with an excess of a hot mixture of three volumes of alcohol with one of concentrated aqueous potash. The presence of water is necessary to prevent the precipitation of the potassium salt of the acid, which is sparingly soluble in alcohol. The ester rapidly goes into solution, and after standing for some time, saponification is complete.The acid is isolated by neutralising the product with dilute sulphuric acid, boiling off the alcohol, acidifying the residue, and taking up in ether. The residue from the ether is crystallised a few times from glacial acetic acid. The acid is thus obtained in prismatic crystals which melt at 262' and contain 2 mols. of water of crystallisation : C = 72.1 ; H = 4.8. C,,H,006 requires C = 72.1 ; H = 4-6 per cent. 0.3008, at 140°, lost 0.0251 H,O. The dried acid gave the following results on combustion : 001303 gave 0.3391 CO, and 0.0482 H20. C,,H,,O, requires C = 71 *1 ; H = 4.1 per cent. The acid dissolves very readily in alcohol, ether, ethyl acetate, or acetone, but is somewhat sparingly soluble in glacial acetic acid, and very sparingly eo in chloroform or benzene.The zinc and magnesium salts are soluble, and the calcium and barium salts sparingly so in water. Those of copper, iron, lead, and silver are formed as amorphous precipitates by treating the ammonium salt of the acid with a soluble salt of the appropriate metal. H,O=9*1. C,3H,60,,2H,0 requires H20 = 9.3 per cent. C = 70.9 ; H= 4.1.1322 MILLS AND EASTERFIELD : CO,H The readily soluble ester obtained by esterifying the product of the oxidation of as-di benzoylniesitylenic acid is saponified by treating its solution in methyl alcohol with an excess of methyl alcoholic potash. After 6 hours, the mixture is diluted with water and heated on the water-bath to drive off the methyl alcohol ; it is then acidified, and the acid extracted with a considerable volume of ether and purified as described under the oxidation of 8-dibenzoylmesitylenic acid, It is obtained from its solu- tion in glacial acetic acid as a fine, crystalline powder, from alcohol as fine, matted, silky needles, and melts a t 213' : 0.1098 gave 0.2855 CO, and 0.0412 H,O.It is almost insoluble in chloroform or benzene, very sparingly soluble in ether, and sparingly so in glacial acetic acid. It is very soluble in acetone. I n alcohol, it dissolves readily, but crystallises well from the somewhat concentrated solution. The lead, copper, and silver salts of the acid are sparingly soluble and the calcium, barium, zinc, and magnesium salts are soluble in water. Saponification takes place readily in the cold. C = 70.9 ; H = 4.2. C2,H1606 requires C = 71.1 ; H = 4.1 per cent.Dibenxoyltrinzesic Acid, ( C6H, CO),C,H (CO,H),. Dibenzoylmesitylenic acid is dissolved in sodium carbonate and heated with a slight excess of potassium permanganate for 2-3 hours until decolorisation has taken place. The manganese dioxide is filtered off and the filtrate acidified with dilute sulphuric acid. The precipitate, which forms at once, is filtered off, and dibenzoyltrimesic acid then separates out slowly in the course of several hours. It is obtained pure by redissolving in alkali, repeating the above process, and then crystallising from glacial acetic acid. It crystallises from water in rosettes of needles. The crystallised acid contains 1; mols. of water of crystallisation : The pure acid melts at 249-250°. 0*381'7 air-dried acid lost, at 170', 0.0222 H20.The anhydrous acid is a hygroscopic powder. On analysis : 0,1412 gave 0.3410 CO, and 0.047 H20. H,O = 6.2. C,,H,,O,,l~H,O requires H,O = 6.4 per cent. C = 65.9 ; H = 3.7. C,,H,,O, requires C = 66.0 ; H = 3.35 per cent.DEElVATIVES OF DIBENZOYLMESITYLENE. 1323 The acid is very sparingly soluble in chloroform or benzene and somewhat sparingly so in cold glacial acetic acid. Alcohol or ether dissolves it readily. Boiling water takes it up in fair quantity, but deposits the greater part again on cooling. The calcium salt may be obtained as a slowly crystallising syrup by boiling the acid with calcium carbonate until neutral, filtering, and concentrating, A solution of the calcium salt in water remains clear when treated with solutions of barium or magnesium salts, but gives precipitates with those of silver, copper, or lead.Twenty grams of dibenzoylmesitylene are dissolved in 700 C.C. of alcohol and boiled for 4-5 hours with 200 grams of zinc dust, with the occasional addition of a few C.C. of concentrated aqueous potash. The zinc dust is filtered off, the alcoholic solution concen- trated, and the reduced product then precipitated by the addition of water and taken up in ether. The ethereal solution is dried and evaporated and the residue distilled a t a pressure of less than 50 mm. The distillate goes over mainly between 320' and 330'; it is a resin- ous, amber-coloured mass, which has not yet been obtained crystalline. It is very soluble in all organic solvents with the exception of light petroleum. Bi benxy hesitylene, ( CH,),C6H( CH,*C,H,),. Ten grams of dihydroxydibenzylmesitylene were heated with 200 C.C. of hydriodic acid (b. p. 127') and 2 grams of yellow phos- phorus for 3-4 hours in a reflux apparatus. The mixture was diluted and extracted with ether; the ethereal solution, washed free from hydriodic acid and dried with potash, was evaporated and the residue distilled under 20-30 mm. pressure, The hydrocarbon went over almost completely at 280' as a clear, faintly greenish- yellow, viscous liquid, which cry stallised on standing. After repeated recrystallisation from alcohol, it was obtained in the form of beautiful, highly refractive crystals melting at 89". On analysis: 0.1005 gave 0.3382 CO, and 0.0710 H,O. The vapour density was determined by Victor Meyer's air-displace- ment method at the temperature of boiling sulphur. In an atmo- sphere of nitrogen (in which the experiments were carried out), the substance is perfectly stable a t this temperature : C = 91.8 ; H = 7.8. C23H,, requires C = 92.0 ; H = 8-0 per cent.1324 COHEN AND DAKIN: 0~1000 gave 7.45 C.C. at 13' and 756 mm. Density= 159. 0.1050 ,, 7.6 ,, 15 ,, 757 ,, Density = 165. C,,H,, requires density = 150. Dibenzylmesitylene is soluble in all the common organic solvent^, It is best crystallised from alcohol, in including light petroleum, which it is only sparingly soluble in the cold. P a r t of the expense incurred in this work was defrayed by a grant made by the Research Fund Committee of the Chemical Society, for which the authors desire to express their indebtedness. UNIVERSITY CHEMICAL LABORATORY, CAMBRIDGE.

ISSN:0368-1645    

DOI:10.1039/CT9028101311

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

1324 COHEN AND DAKIN: CXXXIV.-- The Chlorination of the Dichlo?*otoluenes in Presence of the Aluminium-Mercury Couple. The Coiastitution o f the Trichlorotoluenes. By JULIUS €3. COHEN and HENRY D. DAKIN. THE present research is an extension of a previous investigation on the chlorination products of toluene (Trans., 1901, 79, 1111). I t was shown that five out of six possible dichlorotoluenes were produced by the direct action of chlorine on toluene in the presence of a carrier ; and we have now investigated the further action of chlorine on these substances, A historical summary of investigations on this subject has already been given (Zoc. cit.), so that it is unnecessary to do more than briefly to state the results of previous observers. Limpricht (Annulen, 1866, 139, 303) obtained a trichlorotoluene melting at 73", whilst Aronheim and Dietrich (Ber., 1875, 8, 1401) obtained the same substance, together with a liquid which they considered to be an iso- meric trichlorotoluene.Since all the trichlorotoluenes are solid at the ordinary temperature, the latter substance must have been impure. The solid trichlorotoluene, which was probably mainly composed of 2 : 4 : 5-trichlorotoluene, was also obtained by Schultz (Annalen, 1877, 18'7, 274). Seelig (Annalen, 1887,237,133) succeeded in isolating two trichlorotoluenes, and these are the only two compounds which have any claim to be regarded as pure substances. Both trichlorotoluenes were produced by the chlorination of either 0- or p-chlorotoluene, and were separated by fractional sulphonation. Their constitution was deter- mined as follows.The trichlorotoluene, m. p. 41°, gave a dinitrocom-THE CONSTITUTION OF THE TRICHLOROTOLUENES. 1825 pound which was reduced to the corresponding diamine. This sub- stance yielded an anhydro-base on boiling with acetic anhydride, indicating that it was an ortho-diamine, whence it follows that the parent substance is 2 : 3 : 4-trichlorotoluene : I n a similar way, the trichlorotoluene, m. p. SZ', gave a base which on oxidation yielded a quinone, indicating that i t was a para-diamine, from which it follows that the parent substance is 2 : 4 : 5-trichloro- toluene : CH, CH3 CH, o:/ c1 -+ CII ):o \/ c1 CI!,/NO, C1 Cdj/NH2 c1 \/ c1 N02/\C1 NH,/\Cl It has previously been shown that 2 : 6-dichlorotoluene is one of the products of chlorination of toluene, and it is difficult to imagine that this substance would give either of the above trichlorotoluenes upon chlorination ; it appeared probable that some trichlorotoluenes may have been overlooked by previous observers.Since, as previously stated, five out of a possible six dichlorotoluenes are produced during the chlorination ol toluene, we have used these pure dichlorotoluenes as a starting point for further chlorination. By this means, the number of isomerides which can be formed in each case is greatly reduced, and the possibility of detecting the different trichlorotoluenes is correspondingly increased. The products of chlor- ination, which are all solid a t the ordinary temperature, were separ- ated and identified by means of their melting points and by the melt- ing points of their dinitro-derivatives and of the trichlorobenzoic acids which they give on oxidation.In order to compare the products thus obtained with pure substances of known constitution, we have syn- thesised the six trichlorotoluenes and have obtained from them the nitro- and dinitro-derivatives and the trichlorobenzoic acids. Our results may be summarised as follows. The five dichlorotoluenes known to be produced by the chlorination of toluene give when further chlorinated three, and probably four, trichlorotoluenes. Thus out of fifteen mono-, di-, and tri-chlorotoluenes theoretically possible, no less than eleven have been isolated from the products of the chlorination of toluene. 3 : 5-Dichlorotoluene, which is not formed by the direct chlorination of toluene, gives rise to a fifth trichlorotoluene when further chlorinated.1326 COHEN AND DAKIN: The progressive chlorination of toluene is represented in the accom- panying diagram, the arrows indicating the compound produced by the further action of chlorine.Chlorination of toluene. /' 1 2 4 3 ~ ( ) L J f - j ( J Q 2 : 3 2 : 4 2 : 5 2 : 6 3 : 4 3 : 5 2 : 4 : 6 2 : 3 : 6 2 : 4 : 5 2 : 3 : 5 3:4:6 2 : 3 : 4 We are already engaged upon the investigation of the ,tetrachloro- toluenes, and so defer drawing any theoretical deductions until that part of the work is completed.THE CONSTITUTION OF THE TR~CHLOROTOLUENES. 1327 E x P E:RI M E NT AL. For purposes of reference the experimental part is divided into the (I) Preparation of the six trichlorotoluenes and their derivatives.(11) Chlorination of the six dichlorotoIuenes. following sections : I.-Prepam5on of the Six Trichlorotoluenes and their Derivatives. 2 : 3 ; 4-T~ichbroto~uena. 2 : 3 : 4-Trichlorotoluene was prepared from 4-nitro-2 : 3-dichloro- toluene. It was found that the dinitro-compound obtained by nitrat- ing 2 : 3-dichlorotoluene (Trans., 1901,79, 1128) gave a base, on reduc- tion with tin and hydrochloric acid, which had the properties of a meta-diamine, indicating that the constitution of the dinitro-compound must be represented thus : CH, The regulated nitration of 2 : 3-dichlorotoluene gives rise to a mono- nitro-derivative, which must therefore be represented by one of the following formuh : On reducing this nitro-compound and substituting chlorine for the amino-group, a trichlorotoluene was obtained which was not identical with 2 : 3 : 6-trichlorotoluene prepared by other methods, and must therefore be the 2 : 3 : 4-compound.The trichlorotoluene agreed in all respects with the trichlorotoluene obtained by Seelig by the chlorina- tion of both 0- and p-chlorotoluenes, t o which, for reasons already given, he also ascribed the 2 : 3 : 4-constitution. A better method than that previously described for the preparation of 2 : 3-dichloro-4-nitrotoluene is to dissolve 2 : 3-dichlorotoluene in slightly more than its own volume of fuming nitric acid, keeping the mixture cool. After some time, water is added, and the precipitated nitro-compound filtered off and crystallised from alcohol.The nitro- group was reduced by means of tin and hydrochloric acid, the reaction,1328 COHEN AND DAKIN: which is very vigorous, being completed by warming on the water-bath. Excess of caustic soda was then added, and the base separated by steam distillation. The base readily solidifies and melts at 40-42'. It is very soluble in alcohol, and forms a finely crystalline hydro- chloride. The acetyl derivative, C7H,C1,*NH*CO*CH,, was prepared by heat- ing the substance with acetic' anhydride, and crystallised well from alcohol in needles melting at 128-129'. Og1O85 gave 0.1421 AgCl. C1= 32.4. C,H,0NC12 requires C1= 32.5 per cent. The hydrochloride of the base was diazotised, and the amino-group replaced by chlorine in the usual way, using cold cuprous chloride solution.On distillation in a current of steam, a good yield of tri- chlorotoluene was obtained. It crystallised from alcohol in needles melting at 40-41O. 2 : 3 : 4-Tr~chZoronitrotoZuene.-This substance was prepared by dis- solving the finely divided trichlorotoluene in cold fuming nitric acid. After some time, the nitro-compound was precipitated with water and crystallised from alcohol. Long, white needles melting a t 60-61' were obtained, agreeing in properties with the compound previously described by Seelig. 2 : 3 : 4-YrichZoro-5 : 6-dinitrotoZuene.-This substance was obtained by nitrating the trichlorotoluene as described by Seelig, and was crystallised from alcohol. White needles were obtained melting at 2 : 3 : 4-Trichlo~obenxoic Acd.--The trichlorotoluene was oxidised with dilute nitric acid in a sealed tube at a temperature of 150'.After the usual purification, the substance crystallised from hot water in needles melting at 186-187'. 000659 gave 0.1265 AgC1. C1- 47.4. C7H,0,CI, requires C1= 47.2 per cent. 2 : 3 : 4-Trichlorobenzoic acid has been described by Seelig as melting a t 129'. He obtained it from trichlorobenzylidene chloride, which was converted into the aldehyde and then oxidised to the acid by means of potassium permanganate. The description given leads us to infer that his acid was impure, for, amongst other properties, the sub- stance melted under water at SO', whereas the acid obtained from tri- chlorotoluene by means of nitric acid is solid at the temperature of boiling water.On analysis : 140 -1 4 1'. On analysis :THE CONSTITUTION OF THE TRICHLOROTOLUENES. 1329 2 : 3 : ~-TT~c~~wo~oZWTM. 2 : 3 -: 5-Trichlorotoluene was prepared by two different methods. (a) Preparation from 3 : 5-dichloro-2-aminotoluene :-3 : 5-Dichloro- o-acetotoluidide is easily obtained by adding an excess of bleaching powder solution to o-acetotoluidide dissolved in five parts of glacial acetic acid. The oily '' nitrogen chloride " of 5-chloro-2-acetotoluidide is precipitated, and after separation and warming with acetic acid and a trace of sulphuric acid, is almost quantitatively converted into 3 : 5-dichloro-2-acetotoluidide (Chattaway and Orton, Trans., 1900, 7'7, 791). The acetyl group was removed by hydrolysing the compound with hydrochloric acid in a sealed tube a t a temperature of 130'.'rho base was separated by addition of caustic soda followed by steam dis- tillation. The amino-group was replaced by chlorine by means of Sandmeyer's reaction, using cold cuprous chloride solution. The tri- chlorotoluene was readily volatile in steam and was collected and frac- tionated under the ordinary pressure. Twenty-five grams of dichloro- acetotoluidide gave 20 grams of pure trichlorotoluene, boiling at 229-231' under 757 mm. pressure. The substance solidified to a mass of hard crystals melting at 45-46' and crystallised readily from alcohol in the form of long, white needles. (6) Preparation from 3-nitro-5-chloro-2-aminotoluene :-m-Chloro-o- acetotoluidide is readily prepared either by the direct action of chlorine on o-acetotoluidide (Lellman and Klotz, AnnaEen, 1885, 231, 319) or by the action of sodium hypochlorite solution on o-acetotoluidide in pres- ence of sodium bicarbonate (Chattaway and Orton, Trans., 1900, 77, 790).Claus and Stapelberg (Annulen, 1893, 274,296) state that the nitra- tion of 5-chloro-o-acetotoluidide is invariably accompanied by the pro- duction of tarry matter. They succeeded in isolating a nitro-deriva- tive by working in sulphuric acid solution and separated the tarry matter by crystallisation from petroleum. Our experiments do not confirm these results. 5-Chloro-o-scetotoluidide may be readily nitrated by adding it in small portions at a time to a mixture of four parts of fuming nitric acid and one part of glacial acetic acid. The tempera- ture should be kept between 15' and ZOO.After standing for a short time, the solution is poured on to ice and the precipitated chloronitro- acetotoluidide cry stallised from alcohol. There is not the smallest appearance of tarry matter and the yield is excellent. 5-Chloro-3- nitro-2-acetotoluidide crystallises in white, prismatic needles melting at Claw and Stapelberg recommend that the hydrolysis of the acetyl derivative should be effected by heating for 12-14 hours with alco- 1 9 7-1 9 8'.1330 COHEN AND DAKIN: holic hydrochloric acid. It was found, however, that boiling the substance for a few minutes with sulphuric acid diluted with its own volume of water gave an equally satisfactory result. On diluting the acid aolution, the base is precipitated and may be recrystallised from alcohol.The substance crystallises in fine, long, orange-y ellow needles melting at 129-130'. It is noteworthy that the melting point of this base is very near to that of a substance obtained by Claus and Stapel- berg by treating the nitrate of 5-chloro-2-aminotoluene with strong sulphuric acid, and regarded by them as containing the nitro-group in the para-position. The chloronitroaminotoluene mas converted into dichloronitrotoluene by means of Sandmeyer's reaction. The product is readily volatile in steam and crystallises from alcohol in long, slender needles melting at, 54-55', On analysis : 0,1125 gave 0.1575 AgC1. C1= 34.6. C7H,0,NC12 requires 01 = 34.4 per cent. The nitro-group was reduced by means of tin and hydrochloric acid.The solution was warmed for a short time to start the reaction, which subsequently proceeded vigorously. At first, a thick, solid mass separ- ated out, which nearly all went into solution on further addition of hydrochloric acid. Sodium carbonate was subsequently added until a small permanent precipitate was obtained, and the dichlorotoluidine then separated by distillation in steam. The base crystallised very readily from a!cohol in tufts of white needles melting sharply a t 69-70'. On analysis : 0.0360 gave 0.0582 AgC1. C1=40*0. C,H7NCl, requires C1= 40.3 per cent. The amino-group was replaced by chlorine, using the ordinary method, and the trichlorotoluene separated by steam distillation. The product melted sharply at 45-46', and the melting point was unchanged by recrystallisation from alcohol, The yields throughout this rather long series of reactions were excellent, and the product was identical with that obtained by the more direct method.2 : 3 : 5-TrichZoronitrotoZuerte, C7H,C1,*N0,.-This substance was prepared either by nitrating 2 : 3 : 5-trichlorotoluene with a mixture of three parts of concentrated nitric acid (sp. gr. 1.4) and four parts of con- centrated sulphuric acid and heating the mixture; or, preferably, by dissolving the finely divided trichlorotoluene in cold fuming nitric acid. The nitro-compound was precipitated by the addition of water, and after repeated crystallisation from alcohol or slightly diluted acetic acid, was obtained in felted masses of fine needles melting a t 58-59". On-analysis :THE CONSTITUTION OF THE TRICHLOROTOLUENES, 1321 0.1151 gave 0*2080 AgC1.C1= 44.6 C7H402NCl, requires C1= 44.2 per cent. 2 : 3 : 6-Trichloro-4 : 6-dinitrotoluene, C1H3C13( NO,),.-The addition of six parts of fuming nitric acid and four parts of sulphuric acid to one part of trichlorotoluene resulted in the formation of the dinitro-com- pound. The substance crystallises well from a mixture of alcohol and glacial acetic acid in shining, flattened needles melting a t 149-1503. On analysis : 0.2028 gave 0,3006 AgC1. C1= 36.7. C7H,04N2CI, requires C1= 37.2 per cent. 2 : 3 : 5-Frichlorobenxoic Acid.-Oxidation was effected by means of 20 per cent, nitric acid in a sealed tube at a temperature of 140". The acid crystallises best from large quantities of hot water and melts at 162O.This trichlorobenzoic acid has also been obtained by Matthews (Trans., 1901, '79, 47) by the action of alkalis on the hexachloride of benzonitrile. The description of the properties of the substance there given accords with thoRe of our preparation, and the synthesis of this acid from trichlorotoluene confirms the constitution arrived a t by Matthews from indirect evidence. 2 : 3 : 6-Trichtorotoluene. The starting point for the preparation of 2 : 3 : 6-trichlorotoluene was o-acetotoluidide, which was converted into 2 : 3-nitrotoluidine by the method of Reverdin and Crdpieux (BOY., 1900, 33, 2498). The 2 : 3-nitrotoluidine was diazotised and converted into chloronitrotoluene by means of Sandmeyer's reaction, and was then reduced with tin and hydrochloric acid to 2 : 3-chlorotoluidine.The latter was heated on the water-bath for an hour with an equal weight of acetic anhydride and converted into the acetyl derivative melting :at 126-128'. A second chlorine atom was introduced by passing chlorine through the substance dissolved in ten times its weight of acetic acid. After a short time, crystals separated, and in spite of the large amount of solvent, the mass became pasty. When saturation was complete, water was added, when the crystals dissolved and a clear solution was ob- tained which soon became turbid through the deposition of a mass of needle-shaped crystals of the 2 : 6-dichloro-3-acetotoluidide. The sub- stance was recrystallised from alcohol and forms long needles which melted a t 120-122'. 0*1038 gave 0*1381 AgC1.C1= 32.8. C,H90NCl, requires C1= 32.5 per cent. The acetg 1 compound was h ydrolysed with strong hydrochloric acid at 1 30', and the hydrochloride of the base, which was filtered off, was It was analysed with the following result :1332 COHEN AND DAKIN: converted into the trichlorotoluene by Sandmeyer's reaction. The base is precipitated from the hydrochloride with alkali, and crystallises from dilute alcohol in colourless needles which melt at 59-60°. 2 : 3 : 6-Trichlorotoluene crystallises from alcohol i n colourless needles which melt a t 45-46O. The position of the second chlorine atom wag determined by replacing the amino-group in the dichlorotoluidine by hydrogen, using the method of Chattaway and Evans (Trans., 1896, 69, 850).The liquid obtained in this way formed a dinitro-derivative which melted a t 121-122°, this being the melting point of 2 : 6-di- chlorodinitrotoluene. The various reactions offer no difficulties and the yields are good throughout. 2 : 3 : 6-Trichlo~~onitrotoluene, C7H4C13*N0,.-Finely divided 2 : 3 : 6-tri- chlorotoluene was dissolved in cold fuming nitric acid. The nitro-com- pound was precipitated with water and crystallised several times from alcohol. The:substance forms brilliant, long needles melting at 57-58'. On analysis : 0,1148 gave 0.2050 AgC1. C1= 44.1, C7H402NCl, requires C1= 44.2 per cent, 2 : 3 : 6-17richho-4 : 5-di?zitrotohene, C7H3C13(N02),.-This substance was obtained by nitration in the ordinary way, and crystallises from acetic acid in fine prisms melting at 140-142O.On analysis : 0.3491 gave 0.5210 AgC1. Cl=36*9. C7€€,0,N,CI, requires C1= 37.2 per cent, 2 : 3 : 6-Trichlorobe~axoic Acid.-On oxidation in the usual way, the trichlorotoluene gave 2 : 3 : 6-trichlorobenzoic acid, which crystallises from hot water in white, flaky crystals with a satin-like lustre and melts at 163-164'. On analysis : 0.0578 gave 0.1110 AgC1. 01=4704. C7H302C13 requires C1= 47.2 per cent. 2 ; 4 : 5 17richlorotoZuene. (a) Preparation from m-acetotoluidide :--m-A4cetotoluidide was chlorinated with bleaching powder solution in presence of acetic acid. The reaction is similar t o the chlorination of o-acetotoluidide, studied by Chattaway and Orton (Trans,, 1900, 77, '791). A solution of 20 grams of m-acetotoluidide dissolved in 80 C.C.of glacial acetic acid was added to a filtered solution of 35 grams of bleaching powder in 600 C.C. of water. A heavy oil separated out and a considerable rise in temperature was noted. The oil was pre- sumably the '( nitrogen chloride " of 6-chloro-3-acetotoluidide. On standing, the oil was converted into a hard, white, crystalline masTHE CONSTITUTION OF TEE TRICHLOROTOLDENES. 1333 which was filtered off and repeatedly crystallised from 80 per cent. alcohol. The substance crystallised in fine, long, white needles melting at 156--157', and was evidently the same substance as that obtained by Reverdin and Crdpieux (Bey., 1900, 33, 2503) by treating m-aceto- toluidide with sodium chlorate in hydrochloric and acetic acid solution. The acetyl compound mas readily hydrolysed with 50 per cent.sulphuric acid. On heating, the substance at first dissolved, and on subsequent warming on the water-bath, white crystals of the sulphate of the base separated out from solution. The base was separated by addition of caustic soda followed by distillation in steam. The yield amounted to 8 grams of dichlorotoluidine. The amino-grmp was replaced by chlorine in the usual way and the trichlorotoluene purified by distillation in steam, The substance crystallised from alcohol in long, white needles melting a t 81-82". (6) Preparation from mchloroy- t oluidine :-3-C hloro-4-amino toluene was prepared fromp-acetotoluidide as described on p. 1336. Excess of dilute nitric acid was added to the base and the crystalline nitrate filtered off and thoroughly dried.The nitration was carried out as described by Claus and Davidsen (Annalen, 1891, zsS,j343) by adding the nitrate in small portions a t a time to cold concentrated sulphuric acid. After some time, the chloronitrotoluidine was separated by pouring the solution on to ice. The amino-group was replaced by chlorine by the ordinary method, and on steam distillation a good yield of 6-nitro-3 : 4-dichlorotoluene mas obtained. This substance crystal- lised from alcohol in needles melting a t 63--64' and was apparently identical with the product obtained by the nitration of 3 : 4-dichloro- toluene (Trans., 1901, 79, 1113). The nitro-group was reduced by means of stannous chloride and the base separated by addition of caustic soda followed by distillation in steam.The base crystallised from alcohol in plates possessing a silky lustre and melted at 100-lO1°. On analysis : 0-1213 gave 0.1965 AgCI. C1=40*0. The amino-group was replaced by chlorine and the trichlorotoluene purified by distillation in steam. The substance crystallised from alcohol in long, white needles melting a t S1-82'. ( c ) Preparation from p-ni tro-o- toldidine :-p-Nitro-o-t oluidine is most easily prepared by the following method, which is a modification of that described by Green and Lawson (Trans., 1891, 59, 1013). The o-tolnidine is poured into ten times its weight of concentrated sulphuric acid and cooled to 5' in a freezing mixture. The same weight as the toluidine taken of finely powdered potassium nitrate is gradually added, so that the temperature rises to 10' and remains C,H,NCl, requires 40.2 per cent.VOL, LXXXI. 4 u1334 COHEN AND DAKIN: about that point. The process can be conducted pretty rapidly. Finally, a few C.C. of fuming nitric acid are added to complete the reaction, the end point being easily observed by watching the temperature of the mixture, which suddenly begins to fall. The viscid solution is at once poured on to a small block of ice, when a crystalline mass of the sulphate 'of the base separates and is drained from excess of acid. The sulphate is then dissolved in water, decomposed with sodium carbonate, and the base filtered off and crystallised from alcohol. The yield is rather more than the weight of the toluidine taken. The small quantity of 2 : 6-nitrotoluidine which is formed remains in the mother liquors.The nitrotoluidine was converted into 2-chloro-4-nitrotoluene in the ordinary way, the product being about equal in weight to that of the base employed. The nitro-compound WRS reduced with stannous chloride and hydrochloric acid, the solution made alkaline with caustic soda, and extracted with chloroform, as distillation in steam reduces the yield; 38 grams of chloronitrotoluene gave 24 grams of chloro- toluidine. The nitrate of the base was prepared by adding 10 grams of the base to about 6 C.C. of strong nitric acid diluted with twice its volume of water until methyl-violet paper was turned green. The nitrate was filtered, mashed with a little water, and thoroughly dried. Fourteen grams of nitrate were dropped into 37 C.C.of concentrated sulphuric acid cooled in a freezing mixture; the product was poured into water and the nitro-compound crystallised from alcohol. It melted at 157-160". It may be noted here that the original object of the last operation was to obtain 2 : 4 : 6-trichlorotoluene, on the assump- tion that, by the nitration in strong sulphuric acid, the nitro-group would enter the meta-position relatively to the amino-group. The present reaction offers, therefore, an interesting exception to the general rule, for the nitro-group enters the o-position to the amino- group and the pposition to the chlorine atom. The replacement of the amino-group by chlorine requires double the calculated quantity of sodium nitrite, as the substance does not diazotise readily, but the yield is satisfactory.The 2 :.4-dichloro- 5-nitrotoluene was reduced and then diazotised in the usual way. The crude trichlorotoluene melted at 75", and after one crystallisa- tion from alcohol at 80-82O. That the third chlorine atom had entered position 5 was con- firmed ~ by removing the amino-group in 2-chloro-5-nitro-4-amino- toluene, when chloronitrotoluene was formed, which melted ,at 459 in agreement with the melting point of 2 chloro-5-nitrotoluene pre- pared by Goldschmidt and Honig (Ber., 1886, 10, 2438) from 6-nitro-2-aminotoluene. - wTEE CONSTITUTION OF TEE TRICHLOROTOLUENES. 1335 2 : 4 : 5-Tric~Zoro?2itrotoZuene.-This substance crystallises well from alcohol in needles melting at 91-92', Seelig gives 92' as the melting point. 2 : 4 : 5-Trichloro-3 : 6-dinitrotoZuene.-This substance was prepared in the usual way and melts at 226-227*, as described by Seelig.It is sparingly soluble in acetic acid and only very slightly SO in alcohol. 2 : 4 : 5-TricMorobennxoic Acid.-On oxidation with nitric acid, the trichlorotoluene gave 2 : 4 : 5-trichlorobenzoic acid, which crystallises from dilute alcohol in masses of white, silky needles melting a t 2 : 4 ; 6-Trichlorotoluene. 1 62-1 64'. Symmetrical trichlorotoluene was obtained by the elimination of the amino-group from trichloro-m-acetotoluidide. m-Acetotoluidide is readily chlorinated by means of sodium chlorate and hydrochloric acid (Reverdin and CrBpieux, loc. cit.). Twenty grams of rn-acetotoluidide were dissolved in 80 C.C. of glacial acetic acid; a slight excess of concentrated hydrochloric acid was then added and the solution maintained at 15-25' while 26 grams of sodium chlorate dissolved in the minimum amount of water were in- troduced.After standing for some time, the trichloroacetotoluidide wak precipitated by the addition of water and crystallised three times from alcohol. The substance crystallises well in white, glistening needles. It was found that boiling hydrochloric acid hydrolysed the compound very slowly a t the ordinary pressure, whilst 50 per cent. sulphuric acid was far more effective. On diluting the solution and distilling the acid liquid in steam, the base was carried over and a t once solidified in the receiver, 2 : 4 : 6-Trichlorotoluidine crystallises from alcohol in fine, white glistening needles melting a t 77-78'.0,1057 gave 0'2153 AgCl. The amino-group was removed by the method of Chattaway and Evans (Trans,, 1896, 60, 850). The resulting trichlorotoluene is readily volatile in steam and crystnllises from alcohol in long, white, shining needles melting a t 33-34'. 2 : 4 : 6-TricAlor0-3-niti.otol~ne.-This substance was prepared by nitrating the trichlorotoluene in the usual way and was crystallised from a mixture of acetic acid and alcohol. It forms white, wax7 needles melting, Lot very sharply, a t 5 4 O . On analysis : C1= 50-4. C,H,NCl, requires C1= 50.5 per cent. On analysis : 0.0976 gave 0.1752 AgOl. Cl= 44.4. C7H,0,NC1, requires C1= 44.2 per cent.. 4 u 2:1336 COHEN AND DAKIN: 2 : 4 : 6-Trichloro-3 : 5-dinitrotoZuene.-This substance readily crys- On analysis : tallises from glacial acetic acid and melts at l78-18Oo.0.1093 gave 0.1652 AgCl. C1= 37.3. C7H,0,N,Cl, requires CY = 37.2 per cent. 2 : 4 : 6-TrichEorobenxoic Acid.-On oxidation with dilute nitric acid, the trichlorotoluene was readily converted into the trichlorobenzoic acid, which after purification melted at 160-161°. This acid has also been prepared by Meyer and Sudborough (Bey., 1894, 27, 3152) from s-trichloroaniline. 3 : 4 : 5-171.ichZorotoZzcene. This trichlorotoluene was prepared by two methods : (a) Preparation from dichloro-p-acetotoluidide :-The chlorination of p-acetotoluidide does not take place with the same ease and regularity which characterise that of the 0- and m-compounds. Of the various methods proposed, the more importarit are : (i) the direct action of chlorine on an acetic acid solution of p-acetotoluidide (Lellmann and Klotz, AnnaZen, 1885, 231, 311); (ii) the action of bleaching powder solution on p-acetotoluidide dissolved in acetic acid, followed by conversion of the resulting nitrogen chloride into the chloro-base by means of acid (Chattaway and Orton, Trans., 1900, 77, 789); (iii) the action of sulphuryl chloride on p-acetotoluidide (Wynne, Trans., 1892, 62, 1042). None of these methods is wholly satisfactory, and poor yields are the rule. In the course of some experiments on this subject, it was found that a yield of 80-83 per cent.of m-chlorotolu- idine could be obtained by chlorinating p-acetotoluidide dissolved in glacial acetic acid with sodium chlorate and hydrochloric acid.At first, finely powdered potassium chlorate was employed, but subse- quently it was found preferable to use a saturated solution of thevery soluble sodium salt. If at the conclusion of the reaction the mixture be poured into water, a somewhat sticky mass separates, which solidi- fies after a short time, and from which considerable quantities of chloroacetotoluidide may be separated by careful crystallisation from alcohol. A much better plan, and one which gives a better yield and purer product, is to hydrolyse the crude acetyl derivative and separate the base by steam distillation. The following is a description of a typical experiment. Fifty grams of p-acetotoluidide were dissolved in 100 C.C. of glacial acetic acid and 150 C.C. of concentrated hydrochloric acid.The solu- tion was carefully cooled in ice and a cold solution of 16 grams of sodium chlorate dissolved in the minimum amount of water added in small portions at a time. After a further addition of 100 C.C. of llpdrochloric acid, the clear reddish solution was boiled for two hoursTHE CONSTITUTION OF THE TRICHLOROTOLUENES. 13 37 under a reflux condenser. The acid liquid was then distilled in steam, by which means a trace of oily impurity and some of the acetic acid were removed. On cooling and rendering the solution alkaline with sodium carbonate and subsequently resuming the distillation, 43 grams of crude chlorotoluidine were obtained. The oil was collected, dried over potassium carbonate, and fractionated. It distilled as follows : Below 220 O.................. 1 gram 220-225' ..................40.0 grams Above 225O ............... 2.0 ,, Pure m-chloro-p-toluidine boils at 223-224', and may be easily obtained by redistilling the large fraction boiling a t 220-225' obtained above. A portion of the base was converted into the acetyl derivative which melted a t 113'. The benzyl derivative was also prepared and melts at 137-139'. The latter substance is much more readily crystallised than the acetyl derivative. Although 3 : 5-dichloro-p-acetotoluidide may be obtained by the direct chlorination of p-acetotoluidide, it is preferable to start with pure 3-chloro-4-acetotoluidide prepared as just described. The further chlorination was carried out by means of sodium chlorate, in tha same way as in the preparation of monochlorotoluidine. The dichloro- acetotoluidide was purified by crystallisation from alcohol and melted at 199'.The yield amounted to 47 per cent. of the theoretical amount. Lellmann and Klotz obtained small quantities of the same compound by the direct chlorination of pacetotoluidide. It may be here mentioned that, by the further action of sodium chlorate and hydrochloric acid, 2 : 3 : 5-tric~Zoro-4-acetotoZ~idide, C7H,Cl,NH*CO*CH,, melting at 179O, may be prepared. It crystal- lises from alcohol in colourless needles. C1= 41.9. C,H80NCI, requires 42.1 per cent. On analysis : 0*1000 gave 0.1693 AgCI. The hydrolysis of the dichloro-p-acetotoluidide was effected by heat- ing with concentrated hydrochloric acid in a sealed tube a t a tempera.- ture of 130".The amino-group was replaced by chlorine, and the trichlorotoluene separated by steam distillation. The substance melts at 44-5-45.5'. The conversion of dichloroacetotoluidide into tri- chlorotoluene is almost quantitative. ( b ) Preparation from m-chloro-m-nitro-p-acetotoluidide. 3-Chloro-4- acetotoluidide is readily converted into a nitro-derivative when dis- solved in a mixture of fuming nitric acid aud glacial acetic acid (Claus and Davidsen, AnmaZen, 1891, 265, 344). Fifteen grams of 3-chloro- 4-acetotoluidide, prepared as previously described, were added in small1338 COHEN AND DAKIN: portions at a time to a mixture of 16 grams of glacial acetic acid and 60 grams of fuming nitric acid. The temperature was maintained at about 20'.On pouring the solution into water and crystallising the product from alcohol, the nitro-compound was obtained in the form of fine needles as described by Claus and Davidsen. Hydrolysis was easily effected with boiling hydrochloric acid. 3-Chloro-5-nitro-4-amino- toluene is slightly soluble in water, and distils slowly in steam from both acid and alkaline solutions. It crystallises well from alcohol in orange needles melting a t 72-73'. The amino-group was replaced by chlorine, and the dichloronitrotoluene distilled in steam. This sub- stance crystallises from alcohol in slightly yellow needles melting at 49-50'. On analysis : OD1019 gave 001420 AgC1. C1=34-4. The dichloronitrotoluene obtained was equal in weight to the chloro- nitrotoluidine taken. The nitro-group was reduced with stannous chloride and hydrochloric acid.On cooling the solution, after reduction was complete, crystals of the hydrochloride of the base were deposited. These were filtered off, washed with a little hydrochloric acid, and then distilled in steam with the addition of sodium carbonate. The base gave an acetyl derivative, C7H,Cl,NH*CO*CH,, crystal- lising from alcohol in needles melting a t 158-1559', 0.1742 gave 0.2285 AgC1. C1 = 32.3. C,H,ONCI, requires C1= 32.5 per cent. The amino-group was replaced by chlorine, and after distillation in steam a good yield of trichlorotoluene resulted. The product thus obtained was identical with the trichlorotoluene prepared by the first method. The same substance has been obtained by Wynne (Trans., 1892, 62, 1042) as a derivative of the products of the action of sulph- uryl chloride on pacetotoluidide.3 : 4 : 5-l;rrichloro-2-nitrotol~~~e.-~~is substance crystallises from alcohol in sparingly soluble prisms melting a t 81-82'. On analysis : 0.1000 gave 0.1'770 AgCI. C1= 43.8. C7H,0,NCl, requires C1= 44-2 per cent. 3 : 4 : 5-Trichloro-2 : 6-dinitrotoZuene.-The dinitro-derivative was prepared in the usual way. It crystallises from acetic acid in prismatic needles melting at 163-164', and is very sparingly soluble in alcohol, On analysis : C7H,O2NCl2 requires C1= 34.4 per cent. On analysis : 002045 gave 0.3048 AgC1. C1=36*9. C1H,0,N2Cl requires C1= 37.2 per cent.THE CONSTITUTION OF THE TRICHLOROTOLUENES. 1339 3 : 4 : b-PfichZorobemoic Acid.-The trichlorotoluene is readily oxi- dised with dilute nitric acid at 130'.3 : 4 : 5-Trichlorobenzoic acid crystallises from dilute alcohol in white needles melting at 203O, as described by Claus and Bocher (Bey., 1887, 20, 1626). The melting points of the derivatives of the trichlorotoluenes are collected in the following table : Methyl=1. c1: c1: c1. ~ 2:3:4 2:3:5 2:3:6 2:4:5 2 : 4 : 6 3 : 4 : 5 Trichloro- toluene. 40-41" 45-46 45-46 81-82 33-34 44 -5-45 *5 Trichloronitro- toluene. 60-61" 58-59 57-58 91-92 54 * 81-82 Trichlorodi- nitrotoluene. 140-141" 149-150 140-142 226-227 178-180 163-164 Trichloro- benzoic acid. ~ 186-1 87" 163-1 64 162-1 64 160-161 162 203 11. Chlorination o f the Six Dichl or0 t o7uenes. The dichlorotoluenes were prepared by the methods previously de- scribed (Trans., 1901, 79, 1127), with the exception of 3 : 4-dichloro- toluem, which was obtained from 3-chloro-4-aminotoluene.Chlorination was effected by passing chlorine, dried by being led through concen- trated sulphuric acid, into the substance to be chlorinated. A minute quantity of the aluminium-mercury couple was used as '' carrier " in all cases. The reaction was prevented from becoming too violent by careful cooling and by regulating the current of chlorine. I n most cases, it was unnecessary to add any solvent to keep the substance fluid ; moreover, when crystallisation did occur, it was usually an indication that chlorination had proceeded sufhiently far. I n no case was any difficulty experienced in effecting substitution, and the yields throughout were very satisfactory.The only point requiring par- ticular care was to ensure that, on the one hand, the dichloro-compound was all chlorinated, and, on the other, to guard against the formation of higher chlorinated toluenes. Chlorination, of 2 : 3-Dichlorotolzcene. 2 : 3-Dichlorotoluene, chlorinated in the way described, gave tri- chlorotoluene equal to 70 per cent. of the theoretical amount. The substance boiled at 230-240° under the ordinary pressure and melted at 38-40°. On repeated crystallisation from alcohol, a small quantity of a substance of higher melting point was eliminated, probably a tgtrachloro toluene:1340 COHEN AND DAKIN: Oxidation of the Trich2orotoluene.-The oxidation of the trichloro- toluene was especially undertaken with the object of detecting any 2 : 3 : 6-trichlorotoluene, since the trichlorobenzoic acid obtained from this substance could be separated from accompanying benzoic acids by reason of its property of not forming an ester when treated with an alcohol and hydrochloric acid, The crude trichlorotoluene was oxidised with dilute nitric acid in a sealed tube and the acids separated as usual.A portion of the trichlorobenzoic acid was dissolved in ten times its weight of either ethyl or methyl alcohol containing hydrochloric acid, according to Fischer and Speier's method (Bey., 1895, 28, 1150). After the reaction was completed, the solution was poured into water and shaken up with ether or chloroform. (' Unesterified " trichloro- benzoic acid was removed by washing with dilute caustic soda solution and subsequently precipitated from the alkaline solution by means of hydrochloric acid. I t was found, however, that practically the whole (96 per cent.) of the acid had been converted into the ester, and on re- peating the treatment with alcohol and hydrochloric acid no more than the merest traces of acid remained. It would therefore appear that no appreciable amount of 2 : 3 : 6-trichlorotoluene was present in t h e original chlorination product.Another portion of the oxidation product of the trichlorotoluene was crystallised from hot water. The substance separated in white needles melting at 185-187' and was evidently 2 : 3 : 4-trichloro- benzoic acid. Nitration of the T~.ichlorotoluene.-The dinitro-derivative was pre- pared in the usual way and crystallised from alcohol. The substance thus obtained melted a t 134-137".I t was then fractionally crys- tallised from glacial acetic acid. No 2 : 3 : 5-dichloro-4 : 6-dinitro- toluene, m. p. 149-150', was isolated, but a large quantity of a pure dinitro-compound was separated melting at 139-1 40', and identical with 2 : 3 : 4-trichloro-5 : 6-dinitrotoluene. It is therefore concluded that 2 : 3-dichlorotoluene on chlorination gives almost exclusively 2 : 3 : 4-trichlorotoluene, and this affords a simple method of obtaining the latter substance. Chlorination of 2 : 4-Dichlorotoluene. The chlorination of impure 2 : 4-dichlorotoluene, which is the main constituent of the mixture of dichlorotoluenes obtained by chlorinating toluene, has been undertaken by several observers.Seelig (Zoc. cit.) succeeded in proving the prelsence of two out of the three possible ieomerides-the 2 : 3 : 4- and 2 : 4 : 5-compounds. Our results are in agreement with this, and also indicate the probability of a very small amount of the 2 : 4 : 6-compound being present.THE CONSTITUTION OF THE TRICHLOROTOLUENES. 1341 Pure 2 : 4-dichlorotoluene from 2 : 4-nitrotoluidine was chlorinated and gave its own weight of a mixture of trichlorotoluenes boiling at 230-240'. A preliminary separation of its constituents was effected in the following way. The solid product was warmed to 52' in the water-bath and then quickly drained at the pump, the more infusible residue being washed with a little alcohol. By this means, 6.2 grams of almost pure 2 : 4 : 5-trichlorotoluene was separated from 12 grams of the original mixture.After a single crystallisation from spirit, the substance was obtained in the form of fine needles melting sharply a t 81-82O. The more fusible portion of the mixture was dissolved in hot spirit, and an attempt was made to separate further quantities of the 2 : 4 : 5-compound by crystallisation. This, however, was unsuccess- ful, so the alcohol was removed by evaporation and the trichloro- toluene converted directly into its derivatives. Nitration of the Mixed TrichZorotoZuenes.-A portion was nitrated in the usual wag and the product crystallised from a mixture of alcohol and acetic acid. Crystals were obtained of two kinds, which were separated mechanically. The main constituent consisted of needles melting at 137-140°, and these were separated from a smaller quan- tity of indistinct, granular crystals of much higher melting point, which were mainly composed of 2 : 4 : 5-trichloro-3 : 6-dinitrotoluene. The needles, on recrystallisation, melted at 138.5-140.5', and were thus identified as 2 : 3 : 4-trichloro-5 : 6-dinitrotoluene.Oxidation of the Mixed 2'bichZorotoZuenes. -The only other trichloro- toluene which could be present, besides the two already identified, is the 2 : 4 : 6-compound. Since the trichlorobenzoic acid derived from this substance is a di-o-substituted acid and does not readily form an ester when treated with an alcohol in the ordinary way, its separation was attempted by a similar method to that adopted in the case of the chlorination products of 2 : 3-dichlorotoluene.It was found that a small amount of trichlorobenzoic acid was present, which did not form an ester even after four successive treatments with alcohol and hydro- chloric acid. The amount of acid thus separated was approximately 4 per cent. of the total weight of mixed acids taken and melted a t about 136'. It was not found possible to purify the small quantity of acid a t our disposal. The chlorination of 2 : 4-dichlorotoluene, therefore, results in the formation of large quantities of 2 : 4 : 5-trichlorotoluene, a rather smaller amount of 2 : 3 : 4-trichlorotoluene, and probably a very small quantity of the 2 : 4 : 6-compound.1342 COHEN AND DAKIN: Chlorination of 2 : 5-DichZm*otolueme. 2 : 5-Dichlorotoluene is readily chlorinated, the yield of crude tri- chlorotoluenes boiling between 228' and 240' amounting to 86 per cent.of the theoretical amount. The melting point of the preparation mas about 304 but on repeated crystallisation from alcohol it rose to about 75". It was therefore evident that more than one trichloro- toluene was present. After careful fractionation of the dinitro- compounds and separation of the trichlorobenzoic acids, the presence of the 2 : 4 : 5- and 2 : 3 : 6-compounds was determined. No evidence was obtained of the presence of the third possible trichlorotoluene- the 2 : 3 : 5-compound. Nitration of the Mixed ~richZorotoluenes.-The dinitro-compounds were prepared in the usual way and crystallised repeatedly from alcohol or from acetic acid or from a mixture of both solvents.The main product was a substance, melting a t 140-1423 identical with 2 : 3 : 6-trichloro-4 : 5-dinitrotoluene. a f t e r a very large number of crystallisations, a more sparingly soluble portion was obtained which melted at 225-227' and agreed in properties with 2 : 4 : 5-trichloro- 3 : 6-dinitrotoluene. Oxidation of the Mixed 5YrichEorotoluenes.-The trichlorotoluenes were next oxidised with nitric acid in the usual way. When treated with ethyl alcohol and hydrochloric acid, a portion of the trichloro- benzoic acids readily formed an ester. The ester was separated by pouring the alcoholic solution into water and extracting with chloro- form. The non-esterified acid was removed by washing with caustic soda and the solution reserved for subsequent examination.On evaporation of the chloroform solution, the ester readily solidified and was purified by recrystallisation from alcohol. Well-defined, prism- atic needles melting at 63-65" were obtained. The melting point of this substance agrees with that of ethyl 2 : 4 : 5-trichlorobensoate, described by Beilstein and Kuhlberg (Annalen, 1869, 152, 234). The ester was hydrolysed with alcoholic potash and the acid crystallised from boiling water. The substance melted at 160-162' and agreed in properties with 2 : 4 : 5-trichlorobenzoic acid. The caustic soda solution of the non-esterified trichlorobenzoic acid was acidified with hydrochloric acid and the precipitated acid recrys- tallised from hot water. Well-defined needles were obtained which melted at 163--164O, and were identical in appearance with 2 : 3 : 6-tri- chlorobenzoic acid,TEE CONSTITUTION OF THE TRICHLOROTOLUENES.1343 Chlorination, 2 : 6-Dichlorotoluene. 2 : 6-Dichlorotoluene can only give two trichlorotoluenes on chlorina- tion, and of these we have only been able to identify the fL : 3 : 6-deriv- ative. The only simple known derivatives of 2 : 3 : 6- and 2 : 4 : 6- trichlorotoluenes which show sufficient difference in melting point to . render them of service in separating the two substances are the dinitro-compounds which melt at 142' and 180' respectively. The trichlorotoluene obtained boiled at 21 8-225', and melted a t 40-43'. After recrystallisation from alcohol, it melted at 42*5--45', which is very near the melting point of pure 2 : 3 : 6-trichlorotoluene. Nitration of the 27richlorotoZwne.---The dinitro-compound was pre- pared in the usual way and exhaustively fractionated, using acetic acid, alcohol, and ethyl acetate successively as solvents.The main product melted at 140-142', and was easily obtained in a state of purity, This substance is evidently 2 : 3 : 6-trichloro-4 : 5-dinitrotoluene. The remaining portions melted indefinitely at temperatures varying from 110' to 126O ; no pure substance could be isolated from them, and no indication of the presence of 2 : 4 : 6-trichloro-3 : 5-dinitrotoluene, m. p. 180°, was obtained, It is therefore concluded that 2 : 6-dichloro- toluene on chlorination yields the 2 : 3 : 6-derivative almost exclusively, and affords a simple method for its preparation. Chlorination of 3 ; 4-DichZorotoluene, Twenty grams of 3 : 4-dichlorotoluene, prepared from m-chloro-p- toluidine, gave 16 grams of trichlorotoluene b d i n g at 225-2235'. The main portion distilled steadily at 230-231'. The product readily solidified, and melted sharply a t 79-80', A single crystal- lisation from alcohol. gave perfectly pure 2 : 4 : 5-trichlorotoluene, crystallising in long, brilliant needles melting at 81 -82'. Nitration of the TrichZorotoZuene.-The dinitro-compound was pre- pared and crystallised from glacial acetic acid. It melted a t 226-227°, in agreement with pure 2 : 4 : 5-trichloro-3 : 6-dinitrotoluene. No other dinitro-compound was separated, so that it is concluded that the chlorina- tion of 3 : 4-dichlorotoluene results solely in the formation of the 2 : 4 : 5-derivative, and that the reaction affords a good method for the preparation of that substance. ChZorination of 3 : 5-DichZorotoZuene. Since 3 : 5-dichlorotoluene is a solid substance (m. p. 26O), a small quantity (20 per cent.) of carbon tetrachloride was added to prevent solidification. The trichlorotoluene boiled at 235-243', and melted at 43-45'.1344 COHEN AND DAKIN: THE CONSTITUTION OF THE NITRO- The chlorination of 3 : 5-dichlorotoluene can only result in the form- ation of two trichlorotoluenes-the 2 : 3 : 5- and 3 : 4 : 5-derivatives- and of these only one, the 2 : 3 : 5-compound, appears t o be formed. Nitvation of the TrichZorotoluene.-The trichlorotoluene was con- verted into the dinitro-compound in the usual way. The product at first melted at 149-150°, and after recrystallisation at 149-150°, thus corresponding to 2 : 3 : 5-trichloro-4 : 6-dinitrotoluene. No evi- dence was obtained of the presence of 3 : 4 : 5-trichloro-2 : 6-dinitro- toluene, which melts a t 164O. Oxidation of the Z'richlorotoZuene.-The trichlorobenzoic acid was obtained by oxidation in the usual way, and no trichlorobenzoic acid melting a t a higher temperature than 1 6 2 O was obtained, whereas 3 : 4 : 5-trichlorobenzoic acid melts at 203O, so that it is concluded that 2 : 3 : 5-trichlorotoluene is almost exclusively formed in the chlorina- tion of 3 : 5-dichlorotoluene. I n conclusion, we wish to state that we are indebted to the Research Fund Committee of the Chemical Society for a grant towards the expenses of this research. THE PORKSHIRE COLLEGE, LEEDS.

ISSN:0368-1645    

DOI:10.1039/CT9028101324

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

1344 COHEN AND DAKIN: THE CONSTITUTION OF THE NITRO- CXXXV.-The Constitution of the Nitro- and Dinitro- derivcctives of the Dichloyotoluenes. By JULIUS B. COHEN and HENRY D. DAKIN. THE nitro- and dinitro-deiivatives of the six dichloratoluenes have been previously described by us (Trans., 1901, 79, 1111) and have been made use of in identifying the products of chlorination of 0- and p-chlorotoluene. It appeared to be of interest to ascertain the constitution of these substances in order to obtain evidence as to the laws of substitution which hold in the case of substances that are already highly substituted. The following scheme represents the progressive nitration of the dic hlorotoluenes : CH3 ( 3 3 3 O H 3 A. C1f)Ol -+ -+ C1f)Cl \/AND DINITRO-DERIVATIVES OF THE DICHLOROTOLUENES.1345 Thus the nitro-group in the mononitro-compounds occupies the following positions with regard to the methyl group : ortho-position in E, F. meta- ,, A, D. para- > ? B, c. I n regard to one of the chlorine atoms, the nitro-group stands in the following relations : ortho-position in A, B, C, D, E. para- ,, A , c , D, E, F* met a- ,, 16, c, F. The chief directing influence clearly belongs to the chlorine atoms in relation to which the nitro-group enters the ortho- and para- positions. The nitro-group also appears to avoid entering the nucleus between two other groups in the meta-position (C, D, P), which seems to be a case of space interference. When it is unavoidable, it selects the position between a chlorine atom and a methyl group. I n the case of the dinitro-compounds, the position of the first entering1346 COHEN AND DAKIN: THE CONSTITUTION OF THE NITRO- nitro-group appears to be of primary importance in determining the position occupied by the second:; for in all the six dichlorodinitrotoluenes, the nitro-groups are in the meta-position relatively t o one another..EXPERIMENTAL. It was found that the nitro-derivatives of the dichlorotoluenes were, in many cases, most easily prepared by the action. of cold fuming nitric acid at low temperatures, than by the methods previously described in which mixtures of sulphuric acid and small amounts of nitric acid, together with the substance to be nitrated, are heated together on the water-bath. Nitro-derivatives of 2 ; 6-DicliZorotolzcerce. 2 : 6-Dichkwo-3-nitrotoluene.--Nitration in the cold was adopted in case of 2 : 6-dichlorotoluene. Ten grams of dichlorotoluene (b.p. 196-200’) were taken and 20 C.C. of fuming nitric acid added in small portions a t a time. The mixture was thoroughly well shaken and cooled to the temperature of the air between each addition of acid.’ The addition of the last portions of nitric acid resulted in the pro- duction of a perfectly clear solution, from which the nitro-compound was precipitated by the addition of water, The crude product was pressed on a porous tile and then melted at 52-53O. By operating in the manner described, there appears to be no danger of the dinitro-com- ~ o u n d beigg-form&d. The nitro-compound was reduced by means of stannous chloride and hydrochloric acid and the base separated by addition of caustic soda followed by distillation in steam. A portion of the base was boiled with acetic anhydride and the acetg 1 derivative crystallised from alcohol.White, shining needles melting a t 120-122O were obtained, identical with 2 : 6-dichloro-3-acetotoluidide. The remainder of the base was converted into trichlorotoluene by means of Sandmeyer’s reaction, which after nitration gave 2 : 3 : 6-trichloro-4 : 5-dinitro- toluene, meltcng at 140’. 2 : 6-Bichlmo-3 : 5-dinitrotoZuene.--This substance was reduced by means of tin and hydrochloric acid, a little alcohol being added to assist in the solution of the dinitro-compound. After adding caustic soda, the solution was extracted with chloroform. On evaporation, a white, crystalline base was obtained, which gave a brilliant, orange-red coloration with a trace of nitrous acid.The base also gave the chrysoidine reaction for meta-diamines.AND DINITRO-DERIVATIVES OF THB DICHLOROTOLUENES. 134'7 N~t~o-de&vat~ues of 2 : 3 - D i c h ~ 0 t o Z u e ~ ~ 2 : 3-DichEoro-4-n~trotoZuene.--Five grams of 2 : 3-dichlorotoluene were nitrated in the cold with 6 C.C. of fuming nitric acid. The nitro- compound was separated and purified in the usual way and was then reduced with tin and hydrochloric acid. After excess of caustic soda had been added, the base was separated by distillation in steam, and melted at 40-42'. It gave an acetyl derivative melting a t 128-129'. On replacing the amino-group by chlorine, a trichloro- toluene (m.p. 40-41') was obtained, which gave a dinitro-compound, melting at 140-141', identical with 2 : 3 : 4-trichloro-5 : 6-dinitro- toluene . 2 : 3-Dichlmo-4 : 6-dinitroci~Eorotoluene.-This substance was reduced with tin and hydrochloric acid and the resulting diamine extracted from the alkaline solution by means of chloroform. The base crys- tallised in leaflets from alcohol, in which it was readily soluble and slowly darkened on exposure to air. The substance readily responded to the nitrous acid and chrysoidine tests for meta-dinmines. A negative result was obtained on testing the base with an acetic acid solution of phenanthraquinone. Nitro-derivatives of 2 : 5-Dichlorotoluene. 2 : 5-DichZoro-4-nitrotoluene.-A mononitro-derivative of 2 : 6-dichloro- toluene in which the nitro-group was known to occupy position 3 has already been prepared (this vol., p.1330) and as this substance is not identical with the product of nitration of 2 : 5-dichlorotoluene, it follows that the nitro-group in the latter substance must occupy either position 4 or 6. Since 2 : 5-dichloro-3-nitrotoluene, on further nitration, did not give the same dinitro-compound (m. p. 100-101') as is produced by the nitration of 2 : 5-dichlorotoluene, but a substance melting at 69', it appeared probable that position 3 was not substi- tuted in either the mono- or dinitro-derivatives of 2 : 5-dichlorotoluene. This supposition was confirmed in the following way :-2 : 5-Di- chlorotoluene was nitrated with fuming nitric acid and the nitro- compound separated as usual.On reduction with tin and hydro- chloric acid, a base was obtained which was readily volatile in steam and crystallised from alcohol in lustrous leaflets melting at 91-92'. This base was shown to be 2 : 5-dichloro-4aminotoluene by converting it into 2 : 4 : 5-trichlorotoluene, which was obtained in the form of long, white, characteristic needles melting at 80-82'. 2 : 5-Dkhho-4 : 6-dinitrotoZue7~e.-The second nitro-group in this substance was shown to occupy position 6, by reducing the dinitro-1348 COHEN AND DAKIN: THE CONSTITUTION OF THE NITRO- compound to a base, which readily gave the nitrous acid and chryso- idiiie reactions for a meta-diamine. Negative results were obtained on applying tests for ortho- and para-diamines. Nityo-derivatives oj 2 ; 4-Dichlorotoluene.2 : 4-DichZoro-5-nitrotoZuene.-The constitution of this substance was determined by two methods, (i) by synthesis, (ii) by conversion into 2 : 4-dichloro-5-acetotoluidide and subsequently into 2 : 4 : 5-trichloro- toluene, (i) p-Nitro-o-toluidine was converted into 2-chloro-4-nitrotoluene, and this substance was then reduced by means of stannous chloride and hydrochloric acid to o-chloro-p-toluidine. The dry nitrate of this base was added t o cold concentrated sulphuric acid and the resulting 2-chloro-5 -nitro-4-aminotoluene purified by crystallisation from alcohol. The amino-group in this substance was replaced by chlorine by means of Sandmeyer's reaction and the 2 : 4-dichloro-5-nitrotoluene separated by distillation in steam. The product was found to be identical with the 2 : 4-dichloronitrotoluene prepared by the nitration of 2 : 4-di- chloro t oluene.(ii) The nitro-compound was reduced by means of stannous chloride and hydrochloric acid and the base separated by steam distillation of the alkaline solution. The substance melted at 87", and was identical with 2 : 4-dichloro-5-aminotcluene. On heating with acetic anhydride, an acetyl derivative was formed which melted at 156-157', agreeing with 2 : 4-dichloro-5-acetotoluidide, previously prepared by the chlorination of m-acetotoluidide. The amino-group in the base was replaced by chlorine, using Sandmeyer's reaction, and 2 : 4 : 5-trichlorotoluene ob- tained which melted a t 80--82O, after crystallisation from alcohol. 2 : 4-DicTdoro-3 : 5-dinitrot0Zuene.-The dinitro-derivative, on reduc- tion, gave a base which responded to the nitrous acid and chrysoidine tests for meta-diaminee.An alcoholic solution of the base did not give a precipitate with phenanthraquinone dissolved in acetic acid. Nitro-derivatives qt 3 : 5-DiclJoroto2uene. 3 : 5-DicT~loro-2-nitrotoZuene.-The constitution of the mononitro- derivative of 3 : 5-dichlorotoluene can only be represented by one o€ two possible formula The nitro-compound was reduced by tin and hydrochloric acid, and the base, which does not readily form a hydro- chloride, was extracted from the acid solution by means of chloroForm. The crude base melted a t 58-60', and this melting point was un- changed by crystallisation from alcohol. The melting point agreesAND DINITRO-DERIVATIVES OF THE DICHLOROTOLUENES.134 9 with that of 3 : 5-dichloro-4-aminotoluene prepared by Lellmann and Klotz (Annalen, 1885, 231, 322), but the acetyl derivative melts at 185-181', agreeing, therefore, with 3 : 5-dichloro-2-acetotoluidide. The trichlorotoluene obtained from the base, and its nitro- and dinitro- derivatives, corresponded in properties with the 2 : 3 : 5-compound and its nitro- and dinitro-derivatives. The melting point, therefore, of 3 : 5-dichloro-2-aminotolu6ne is 58-60', and not 56' as usually given. 3 : 5-Dichloro-2 : ?-dinitroto1uene.-The constitution of this dinit,ro- compound can only be represented by two formulae, namely, 3 : 5-di- chloro-2 : 4-dinitrotoluene and 3 : 5-dichloro-2 : 6 dinitrotoluene. We have not yet succeeded in ascertaining which is the correct formula, as both substances yield meta-diamines on reduction.Nitro-derivatives of 3 : 4-Dichlorotoluene. 3 : 4-Dicldoro-6-nit~*otoZuene.--The constitution of this substance was determined by synthesis, 3-Chloro-4-aminotoluene was treated with dilute nitric acid and the dry crystalline nitrate added in small por- tions to cold strong sulphuric acid (Claus and Davidsen, Anncden, 1891, 265, 343). The resulting 3-chloro-6-nitro-4-aminotoluene was converted into 3 : 4-dichloro-6-nitrotoluene by means of Sandmeyer's reaction and the product purified by distillation in steam. The nitro- compound melted a t 63-64' and was identical with the product of nitration of 3 : 4-dichlorotoluene. has been previously prepared from 3-chloro-5-nitro-4-acetotoluidide, and since this substance, on further nitration, gave a dinitro-compound melting at 80--81°, whilst the product of nitration of 3 : 4 dichloro-6- nitrotoluene melts at 91.5-92.5', it was probable that the second nitro-group in the latter substance did not occupy position 5. This supposition was confirmed by the fact that the base obtained on re- ducing the dinitro-derivative with tin and hydrochloric acid gave both the nitrous acid and chryeoidine test for a meta-diamine, thus proving that the second nitro-group occupies position 2. 3 : 4-Dkhloro-2 : 6-diititrotoZucne,-3 : 4-Dichloro-5-nitrotoluene A negative result anthraquinone. THE YORKSHIKE LEEDS. was obtained on testing the base with phen- COLLEGE, VOL. LXXXl

ISSN:0368-1645    

DOI:10.1039/CT9028101344

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

1350 PETERS : IODONIUM COMPOUNDS OF THE TYPE IR’R’’R”’ CXXXV1.-Iodoniurn Compounds of the Type 1R’R”R”’ a72cl the ConJiguration of the Iodine Atom.* By HAROLD PETERS, A.T.C. THE principal object of the work described in this paper was to try and obtain some knowledge of the arrangement in space of the valencies of the polyvalent iodine atom by determining, in the first place, whether compounds of the type IR’R’R”’ can be obtained in isomeric forms. For the preparation of such compounds (Proc., 1900, 16, 62), Prof, Kipping and I were led to study a reaction discovered by Hart- mann and Meyer (Be?*., 1894, 2’7, 502 and 1592), who bdve shown that iodonium bases of the type IR,*OH containing two identical radicles can be obtained by the action of certain metallic hydroxides on a mix- ture of iodoso- and iodoxy-compounds, in accordance with the following equation, cGH5’Io + C,H5*I02 + M*OH = (C,H,),I*OH + MIO,.As it seemed probable that by employing iodoso- and iodoxy-deriv- atives of different aromatic radicles a base of the type IR’RNmOH would be produced, we investigated the action of moist silver oxide on a mixture of molecular proportions of iodosobenzene and p-iodoxytoluene, and found that it was thus possible to prepare phenyl-p-tolyliodonium hydroxide, C,H5-I0 + C6H4Me*I0, c AgOH = $gl>I*OH + AgIO,. G 4 This, the first; known example of a mixed iodonium base,? was isolated in the form of its iodide and a number of its salts were examined. We next employed a mixture of p-iodosotoluene and iodoxybenzene, and with the aid of the same reaction prepared p-tolylphenyliodonium hydroxide, C,H,Me*IO + C,H,*IO, + AgOH = CGH4Me>I-OH + AgIO,, C,H, which again was isolated in the form of its iodide.* This communication, which was presented as a thesis by Harold Peters a t the final examination of the Institute of Chemistry, is a continuation of work already published in the Proceedings in the joint names of Professor Kipping and Harold Peters (Proc., j900, 16, 62). It was carried out at the suggestion of Prof. Kipping and with his assistance, and the cost of the materials was partly met by a grant made to him by the Government Grant Committee of the Royal Society.-F. S. K. -i- Since the publication of our original note on this work, Willgerodt and Schlosser (Bey., 33, 1900, 692) have prepared some mixed iodoiiiuiii basesiii a similar manner.AND THE CONFIGURATION OF THE IODINE ATOM.1351 This salt proved to be identical with the iodide obtained by the first method, and corresponding derivatives of these salts were also iden- tical, a fact from which it mty be concluded, provided, of course, that intramolecular change is excluded, that two of the three valencies of the iodine atom are symmetrically situated with respect to the third. For the further investigation of this problem, it was necessary to prepare a derivative containing some asymmetric group, and to then ascertain whether such a compound could be resolved into different parts. We therefore treated the phenyl-ptolyliodonium iodide with silver bromocamphorsulphonate, and thus obtained a phenyl-p-tolyliodonium bromocamphorsulphonate, which was easily isolated in well-defined crystals. A salt identical with this preparation in crystalline and other properties was obtained by interaction of the p-tolylphenyl- iodonium iodide with silver bromocamphorsulphonate, which fact affords further evidence of the position of two of the iodine valencies with respect to the third.Phenyl-p-tolyliodonium bromocamphorsulphonate was next sub- mitted to systematic fractional crystallisation ; all the crystalline deposits at first obtained were found to be identical in outward pro- perties, and in dilute solutions all had the same molecular rotation, which was practically identical with that of optically inactive salts of bromocamphorsulphonic acids. The fact that the salt is not resolved into isomerides under these conditions points to the conclusion that the three iodine valencies are arranged in one plane, but considering the large number of cases in which the use of a method such as the above fails t o resolve undoubted mixtures of optical isomerides into different fractions, further experi- ments must be made before the matter can be regarded as settled.I n fractionally crystallising various samples of phenyl-p-tolyl- iodonium bromocamphorsulphonate prepared by the first of the two methods referred to above, no difficulty was experienced in obtaining successive deposits of well-defined crystals until a very considerable proportion of the original preparation had thus been separated, after which the mother liquors always gave an oily deposit; the latter seemed to be a mixture of two substances very similar in ordinary properties, and in spite of the results of the optical examination of the first crystalline deposits, it seemed not impossible that a partial reso- lution had occurred. On examining, in a similar manner, the oily residues which were also obtained in the crystallisation of the p-tolylphenyl salt, prepared from iodosotoluene and iodoxybenzene, it was found that here, also, the last mother liquor deposited what appeared to be two different compounds.4 x 21352 PETERS: IODONIUM COMPOUNDS OF THE TYPE IR’R’”’’’ Further investigation showed that the phenyltolyliodonium bromo- camphorsulphonate prepared by the first method consisted of a mixture of the salts of phenyltolyl- and ditolyl-iodonium hydroxides? of which the latter was present in only small proportion; also that the tolyl- phenyliodonium bromocamphorsulphonate prepared by the second method contained a small quantity of what seemed to be diphenyl- iodonium bromocamphorsulphonate. The presence of the salts containing two identical radicles might be accounted for by assuming that during the preparation of the mixed iodonium bases some of the iodoso-compound undergoes decomposition into the iodoxy-derivative, 2C,H,*IO = C,H,*IO, + C,H,I, a reaction which is known to occur on heating with water, and that the latter then interacts with some of the unchanged iodoso-compound, giving the base containing two identical radicles : A different explanation altogether might, however, be possible, namely, that the substance supposed to be phenyltolyliodonium bromo- camphorsulphonate is not the salt of a mixed base, but that it is a mere mixture of diphenyl and ditolyl salts, the formation of which is brought about by an interchange of the phenyl and tolyl radicles on crystallising the bromocamphorsulphonate or a t some earlier stage in the preparation of this salt.That the former, and not the latter, con- clusion is the correct one is amply proved by the experiments which are described below and which may be summarised as follows. The iodide of the base prepared from the product of the interaction of iodoso toluene and iodoxybenzene can be separated by fractional crystallisation into a large portion of the salt having the composition of tolylphenyliodonium iodide and a vesy small quantity of ditolyl- iodonium iodide, easily identified by its characteristic crystalline form.The iodide of the base prepared from the product of the interaction of iodosobenzene andiodoxyt,oluene, does not contain any ditolyliodonium iodide but seems t o contain small quantities of diphenyliodonium iodide; the absence of the former is easily proved owing t o the fact that a mixture of ditolyl- and diphenyl-iodonium iodides is easily resolved into its components by fractional crystaliisation ; the presence of diphenyliodonium iodide, however, is difficult to prove, as it is apparently isomorphous with the mixed iodide and the two compounds are very difficult to separate ; moreover, they have both very indefinite melting or decomposing points.Salts of the mixed base, directly compared with mixtures of the corresponding diphenyl and ditolyl salts, were found to show theAND THE CONFIGURATION OF THE IODINE ATOM. 1333 behaviour of pure compounds and to differ from the artificially pre- pared mixtures. A mixture of iodosobenzene and iodoxytoluene, or of iodosotoluene and iodoxybenzene, when shaken with silver hydroxide, gives a yield of the base, isolated in the form of i t s iodide, corresponding to about 85 per cent. of the theoretical quantity. Iodoxybenzene, shaken with silver oxide and water, does not give any base, even after the lapse of three weeks. Igdosotoluene shaken with water and silver oxide gives only very small quantities of ditolyl- iodoniam hydroxide, Hence, to get 80 per cent.of the theoretical quantity, both compounds must take part in the reaction. The principal product obtained from the mixture of iodoso- and iodoxy-compounds is therefore a definite compound, and not merely a mixture of diphenyl- and ditolyl-iodonium salts. The bromocamphorsulphonate prepared from pure phenyltolyl- iodonium iodide does not give ditolyliodonium iodide when it is decom- posed with potassium iodide. Therefore, the mixed base can be con- verted into the bromocamphorsulphonate, and this salt can be crystal- lised without change. For the purpose of this investigation, i t was necessary to prepare the bromocamphorsulphonate of diphenyl- and ditolyl-iodonium hydr- oxides ; these salts are described later, and i t may be noted here that whereas diphenyl- and phenyltolyl-iodoniu m bromocamphorsulphona t es are isomorphous and very difficult to distinguish from one another, the ditolyl salt is usually obtained in long needles or prisms, absolutely different from the dodecahedra of the other two salts; it is, however, dimorphous, and under certain conditions crystallises in dodecahedra, indistinguishable by inspection from those of the diphenyl salt.E XP E R I MENT A L. Phenyl-p-tolyliodonium Iodide, z$i>I*I. 0 4 Molecular proportions of iodosobenzene and iodoxy t ol uene were shaken with one molecular proportion of silver oxide and 200 C.C. of water for 36 hours; a t the end of this time, all the yellow powder had disappeared, and the liquid had a strong aromatic odour and a very pale yellow colour.It had, however, very slight basic properties, as practically the whole of the base which is produced interacts with the silver iodate, giving phenyl-p-tolyliodonium iodate. The solution was now filtered from the silver oxide diluted to about 400 C.C. with water, and sulphur dioxide passed in until the precipi- tated iodide had become perfectly white. The whole was then warmed on the water-bath until quite free from1354 PETERS: IODONIUM COMPOUNDS OF THE TYPE IR’R’‘R”’ sulphurous acid, the precipitate separated by filtration, and well washed. To the filtrate, a very dilute solution of potassium iodide was then added, in order to convert any sulphate of the base into iodide. The mother liquors were finally evaporated nearly to dryness, but only a very small quantity of the iodide mas deposited, thus showing that it is very sparingly soluble in cold water.The total yield of iodide was 80 per cent, of the theoretical, theloss being ’principally due to the fact that in the reduction of the iodate some of the base splits up into benzene, toluene, and the iodide of the base.” The iodide was purified by recrystallisation from dilute alcohol, from which i t separated in lustrous needles melting and decomposing at 153-154’. I t s melting point, however, depends to some extent on the rate of heating, and may be as low a s 152’ or as high as 1 5 8 O , according as the temperature is raised very slowly or very quickly. The iodide is very sparingly soluble in water, chloroform, acetic acid, or absolute alcohol, but dissolves more freely in hot aqueous alco h 01.An iodine estimation was made with the following result : 0.2750 gave 0.3064 AgT. I= 60.16. C13H,,I, requires I = 60.1 8 per cent. A p-tolplphenyliodonium iodide was now prepared by treating iodosotoluene and iodoxybenzene with moist silver oxide, under exactly the same conditions as those described in the previous experiment. It was isolated in the form of its iodide, and recrystallised from dilute alcohol, from which i t was deposited in needle-shaped prisms. An iodine determination gave the following result : 0.3094 gave 0.3159 AgT. C,,H,,T, requires I = 60.18 per cent. When examined under the microscope, this iodide appeared to be identical with the first preparation and its general behaviour towards solvents was the same as that of the previous one.Its melting point was 153’ to 154’ (slightly variable with rate of heating) and when mixed with the iodide previously prepared the melting point remained unchanged. From these facts, it was concluded’ that the iodides prepared by the two differen: methods are identical. I = 60.21.AND THE CONFIGURATION OF THE IODINE ATOM. 1355 Pherzyl-p-tolyliodoi~m Nitrate, #~~>I*NO,. 6 4 To prepare the nitrate, the iodide was treated with one molecular proportion of silver nitrate in aqueous alcoholic solution, when a pre- cipitate of silver iodide was immediately thrown down, The whole was boiled on the water-bath for fifteen minutes, filtered, and the solution evaporated to a small bulk. The nitrate, which quickly solidified, was then recrystallised from dilute alcohol.It was thus obtained in short needles, melting at 117", which were very soluble in aqueous alcohol. An iodine estimation was made with the following result : 0.3761 gave 0,2349 AgI. I= 34.92. CI,H,,I*NO, requires I = 34.04 per cent. Phenyl-p-tolyliodoium Bromocamphorszcl~honate, C,H,Me C6H5>I*S0, C,oH,,OBr. The iodide of the base which had been previously prepared from iodosobenzene and iodoxytoluene was treated in alcoholic solution with silver bromocamphorsulphonate in molecular proportion ; an immediate precipitation of silver iodide occurred and the whole was warmed gently on the water-bath for some time in order to complete the reaction. The solution was then filtered and left to evaporate at the ordinary temperature.After about four days, it began to deposit crystaIs and crystallisation was continued until about 2 grams of the salt had separated out; the mother liquor was again left to crystallise and so on until several successive crops of crystals had been obtained. These crystals of phenyl-p-tolyliodonium bromocamphorsulphonate consist of well-defined, highly lustrous, dodecahedra which may be grown to a considerable size. They contain water of crystallisation, and in consequence have not a definite melting point, but begin to soften at about 105' and liquefy completely at about 120'. A determination of the water of crystallisation gave the following result : 0.6062 lost 0.0220 H,O at 100". C2,H,604SBrI,H,0 requires H,O = 3.6 per cent. This result agrees with that required for 1 mol.of water, but after having been heated a t 100" for some hours, the salt is somewhat sticky and faintly brown, H,O = 3.6.1356 PETERS: IODONlUM COMPOUNDS OF THE TYPE 1R'H''R'" A halogen determination with the anhydrous salt was made with 0.21 12 gave 0-1476 AgBr + AgI. C,,H,60,SBrI requires Br + I = 34.2 per cent. The anhydrous salt has not a very definite melting point, and softens a t about 162', melting completely a t about 165' when heated quickly. Phenyl-p-tolyliodonium bromocamphorsulphonate crystallises well from dilute acetone, the crystalline deposit being identical with that obtained from dilute alcohol. It is very readily soluble in alcohol or acetone, but only sparingly s3 in ethyl acetate or chloroform, and very sparingly so in cold water.When warmed, it has a very peculiar, rather pungent, highly characteristic odour. XpeciJc Rotation.-Owing to the well-defined character of the crystals of this salt, there was little hesitation in arriving a t the conclusion that the various deposits, which were obtained without difficulty in the manner described above, were identical, and that fractional crys- tallisation of the salt had failed to resolve i t into the salts of two different bases ; this conclusion was confirmed by the following deter- minations of the specific rotations of the various fractions of the salt ; I. 0.5 gram of air-dried salt was dissolved in aqueous methyl alcohol, the solution diluted to 25 C.C. with water, and examined in a 200 mm. tube ; the aean of several concordant readings gave a + 1°48', hence 11.0.6062 gram, under the same conditions, gave a + 2'12', hence IIIa, 0.5 gram of the air-dried salt was dissolved in pure methyl alcohol, and examined under the same conditions as previously ; the mean of several concordant results gave a + 1'58', hence [ a ] D + 49.1'. 11171. 0.5 gram dissolved in water and very little methyl alcohol gave These experiments gave practically the same values for the specific rotation in the case of all the fractions, and taking the mean value of the specific rotation of the air-dried salt (I, 11, and IIIb) as [a], + 45.6', that of the anhydrous compound would be [a] + 46.7' ; from this value the molecular rotation of the salt may be calculated to be [ M I D + 282'. Now the molecular rotation of bromocamphorsulphonic acid is [&I], +270°, hence the above result seems to prove that the base of the salt is practically inactive, assuming that in aqueous methyl alcoholic solution the salt is dissociated to a sufficient extent to give the true molecular rotation of the acid ion.That this is probablythe case may be inferred from the results of the experiments with fraction IIIa! which show that in aqueous methyl alcoholic solution containing the following result : Br + 1 = 34.2. [ U ] D + 45'. [a]D + 45O. a f 1°52', hence [ a ] D + 46.6'.AND THE CONFIGURATION OF THE IODINE ATOM. 1357 very little methyl alcohol the specific rotation is only a little lower than in the case of the solution in anhydrous methyl alcohol. As, however, this might not be the case and as the specific rotation in aqueous solution could not be determined owing to the slight solu- bility of the salt, it seemed desirable to continue the fractional crystallisation until as large a proportion of it as possible had been obtained in a state suitable for examination.On doing so, it was observed that from the last mother liquors a con- siderable proportion of the salt was deposited as a gum from which we were unable to isolate a pure preparation, These observationsseemed to shorn that the original specimen which was thought to be pure phenyl-p-tolyliodonium bromocamphorsulphonate had been resolved into two different fractions; on the other hand, the results of the optical examination of the first deposits indicated that the most sparingly soluble salt was not that of an optically active base.I n order to try and ascertain the nature of the salt in the last mother liquor, small portions of the most sparingly soluble and of the most readily soluble fractions were separately decomposed with potass- ium iodide, whereupon the iodide of the base was precipitated in each case. The iodides appeared to be identical in most of their properties, and they both crystallised in fine, silky needles from dilute alcohol, but the first fraction melted a t about 170' to 175' when heated very quickly, whilst the other melted very indefinitely at about 154'. Very little reliance, however, could be placed on these melting points, as they were not at all sharp in either case, and varied very consider- ably with the rate of heating. Neither iodide gave any divergence to polarised light, but owing to their very slight solubility only extremely dilute solutions could be used.In order to try and determine the nature of the impurity in the phenyl-p-tolyliodonium bromocamphorsulphonate, the p-tolylphenyl- iodonium bromocamphorsulphonate, prepared from iodosotoluene and iodoxybenzene, as described above, was fractionally crystallised. The highest fraction again appeared homogeneous, and identical with the phenyl-p-tolyliodonium bromocamphorsulphonate in physical, optical, and chemical properties, The last mother liquors gave a sticky, gummy mass which crystal- lised with some difficulty from dry ethyl acetate in long needles or prisms melting at about 185O. Portions of the first and last fractions of this salt were separately decomposed with potassium iodide.The iodides thus formed, recrys- talliaed from alcohol, were not identical ; the one from the least soluble portion crystallised in silky needles, whilst that from the most soluble1358 PETERS: IODONIUM COMPOUNDS OF THE TYPE 1R’R”R”’ portion crystallised in octahedra. They melted a t 154’ and 143’ re- spectively, but the melting points were very variable, differing by 10’ or 15’according to the rate of heating. The iodide from the first fraction was also much less readily soluble in alcohol, ethyl acetate, or water than that from the most readily soluble fraction. The discovery of these two salts proved, therefore, that the original phenyl-p-tolyliodonium bromocamphorsulphonate was a mixture.Now, since iodoso-derivatives very readily undergo decomposition when boiled with water or alkali, it seemed probable that such a decomposition might have occurred in the preparation of the mixed base ; using a mixture of iodosotoluene and iodoxybenzene, for example, the former might give iodoxytoluene, which would then interact with the iodosotoluene giving ditolyliodonium hydroxide. In order, therefore, t o test this conclusion, p-ditolyliodoniurn iodide was prepared and its properties studied. Di-p-tolyliodonizcm Iodide, (C,H,Me),~*T. This compound was prepared by shaking iodoso- and iodoxy-toluene in molecular proportion with silver oxide and water. The iodide was then isolated in the usual manner and orpstallised from dilute alcohol, in which it was much more readily soluble than diphenyliodonium iodide.It was thus obtained in octahedral crystals of a very lustrous appearance, melting at 143’ to 156O, according to the rate of heating. An estimation of the halogen was made with the following result : 0*2105 gave 0.2280 AgI. I=58.5. CI4Hl4I2 requires I = 58.3 per cent. In appearance, crystalline shape, melting point, and general be- haviour, this iodide was identical with that obtained by precipitating the most soluble portion of the p-tolylphenyliodonium bromocamphor- sulphonate, and yet so entirely unlike the main portion of that salt that we bad no hesitation in concluding that the latter contained the ditolyl salt as impurity. Di-p-tolyliodonium Brornocamnp~orsul~~onate, (C6H4Me)21’S03’C,oH,*OBr. This salt was prepared from the iodide and silver bromocamphor- It was thus sulphonate and crystallised from alcoholic ethyl acetate.obtained in long needles melting a t 185-186’. A halogen estimation was made with the following result : 0-4034 gave 0.2788 AgBr + AgI. Br + I = 33.8. C,,H,,O,SBBrI requires Br + I = 33.4 per cent,AND TEE CONFTGURATION OF TEE IODINE ATOM. 1359 This salt appeared to be dimorphous, and when crystallised from aqueous alcohol it sometimes separated in dodbcahedra which resembled those of phenyl-p-tolyliodonium bromocamphorsulphonate, and, like the latter, probably contained water of crystallisation. Having learnt the properties of the ditolgliodonium bromocamphor- sulphonate, a fresh investigation of the last mother liquor of the tolyl- phenyliodonium bromocamphorsulphonate led to the isolation of a small quantity of a salt which was proved.to be identical with this ditolyl derivative. I n order to ascertain whether the pheny1.p-tolyliodonium bromo- camphorsulphonate contained the diphenyl base, as seemed very prob- able, the latter was prepared in the usual way and isolated in the form of its iodide which was found to melt a t 168--175O, depending upon the rate of heating (Victor Meyer and Hartmann give 175-176O as the melting point). The iodide was treated, as described above, with one molecule of silver bromocamphorsulphonate and the product recrystallised from alcohol, The salt contained water of crystallisation, as shown by the following determination : 0,8284 lost 0,278 H,O a t looo. A halogen estimation with the anhydrous salt gave the following 0.6051 gave 0.4309 AgBr + Agl.C2,H2,0,SBrI requires Br + I = 35.0 per cent. This snIt crystallised well from dilute alcohol in beautiful, lustrous, well-defined dodecahedra melting at about 165-1 6 8 O when previously dried a t 100'; it also crystallised well from dilute acetone, some of the crystals growing to a good size. It was much less soluble in dilute alcohol than the corresponding ditolyl derivative. On the other hand, it was so similar to phenyl-p-tolyliodonium bromocamphorsulphonate in crystalline form and in all other respects that, except for its rather higher melting point, it would be hard to distinguish it from the latter. For this reason, it was not possible to prove beyond all doubt that the original phenyl-ptolyliodonium bromocamphorsulphonate from iodosobenzene is a mixture of a large percentage of phenyltolyl deriv- ative and a very small percentage of the diphenyl compound, but it seems extremely probable that this is so, H,O = 3.35.C,,H2,0,SBrJ + l-$H,O requires H,O = 3.6 per cent. result : Br + I = 38.4.1360 PETERS : IODONIUM COMPOUNDS OF THE TYPE IR’R’”’’’ Proofs of the Existence of a Mixed Iodoniurn Base. Having proved that one preparation, which was at first thought to be a pure iodonium base, contained diphenyliodonium hydroxide whilst the other contained the corresponding ditolyl base, doubt arose as to the actual existence of a mixed base, and it seemed not impossible that the substance described as the latter might consist of a mere mixture of diphenyl and ditolyl compounds.The following experiments mere made to settle this point. The diphenyl- (melting point about 165-168’) and the phenyltolyl- iodonium bromocamphorsulphonates were directly compared, but with the exception of a slight difference in melting points (3’ or 4’), the two compounds seemed to be identical; a -mixture of the dehydrated salts melted very indefinitely from 153-156’ and softened about 8’ before the phenyltolyl derivative. The iodides of the diphenyl and phenyltolyl bases were examined in a similar manner. Here again the results were not very conclusive, and the melting point of the mixture of the two salts mas only about 5’ lower than that of the phenyltolyl derivative. The dichromates were next examined and were found to have rather more sharply defined melting points tban the other salts.The three compounds were directly compared, with the following results : Salt of diphenyl base crystallised in prisms melting a t 157’ when slowly heated. Salt of ditolyl base crystallised in plates melting a t 140’ when slowly heated. Salt of phenyltolyl base crystallised in prisms melting at 143’ when slowly heated. Action of Silver Oxide on lodoso- and lodoxy-derivatives. As the experiments just described did not settle satisfactorily this question of the existence of a mixed base, the action of silver oxide on an iodoso-compound alone and on an iodoxy-derivative alone mas studied. Iodoxy- and iodoso-benzene were shaken separately with silver oxide and water. After a few hours’ shaking, the iodoso-derivative gave some iodide when treated in the usual way, but the iodoxy-benzene, even after prolonged shaking, did not give tho slightest trace.Now when a mixture of iodoso- and iodoxy-derivatives is used, the yield of the iodide, as already stated, is 80 per cent. of the theoretical. The experiment just described, therefore, proves that the mixed base is formed by the cooperation of both the iodosobenzene and iodoxy- toluene, and consequently it must be a phenyltolyl derivative,AND TH'E: CONFIGURATION OF THE IODINE ATOM. 1362 Examination of Iodides. -We further proved by direct experiment that a mixture of the iodides of the diphenyl- and ditolyl-iodonium bases is easily resolved into its components by fractional crystallisation. This was done by first dissolving equal proportions, then a large proportion of diphenyl and a small proportion of ditolyl iodides in dilute alcohol and fractionally crystallising.I n both cases, the ditolyl derivative came down in the last fractions and was easily detected. When, on the other hand, the iodide of the pure mixed base was frac- tionally crystallised, not the slightest trace of the ditolyl derivative could be found, The identification of the impurities found in the p-tolylphenyl and phenylp-tolyl bromocamphorsulphonates as the ditolyl and the diphenyl derivatives respectively, and the proof that they exist in only small quantities, due to the formation of the iodoxy- from the iodoso-deriv- ative, and not from any intramolecular change, makes it evident that the mixed base is a definite compound and not a mere mixture of diphenyl- and ditolyl-iodonium bromocamphorsulphonates. Phelnyl-p-tolyliodonium Chloride, C6H4Me>I*Cl. C6H5 This salt was obtained by dissolving the bromocamphorsulphonate in a little aqueous alcohol and adding an excess of an aqueous solution of sodium chloride ; on cooling, the sparingly soluble chloride crystal- lises out in colourless needles. It was also prepared by treating the original mother liquors, which contain the base and the iodate of the base, with hydrochloric acid, when chlorine is evolved and the chloride precipitated. It crystallises well from dilute alcohol in needle-shaped crystals melting at about 193'. A halogen estimation was made with the following result : 0.1 186 gave 0.135 1 AgCl + AgI. C13Hl,ClI requires C1+ I == 49.1 per cent. P~enyl-p-tolyliodonium Dichromate, is easily obtained by dissolving the brornocamphorsulphonate in a little warm alcohol and adding an aqueous solution of potassium dichromate until a slight turbidity is formed. On cooling, the salt crystallises in thin prisms of a beautiful, bright red colour. It melts at 143' and decomposes a t a slightly higher temperature. UXIVERSITY COLLEGE, NOTTINGH AM. C1+ I = 48.9.

ISSN:0368-1645    

DOI:10.1039/CT9028101350

出版商:RSC    

年代:1902

数据来源: RSC

摘要:

1362 CAVEN : THE MOLECULAR CONFIGURATION OF CXXXVIL-The Moleculay ConJiyuration of Yhosphoryl Chloride and its Derivatives. By ROBERT MARTIN CAVEN, D.Sc., F.I.C. THE constitution of phosphoryl chloride may be represented in two ways; either as ClOP:Cl, or OPCI,. I n support of the formula representing an unsymmetrical con- stitution in which the phosphorus atom would be tervalent, Thorpe (Trans., 1880, 37, 388) has adduced evidence based on specific volume determinations under the assumption that the atomic volume of phosphorus in all compounds is constant. Ramaay and Masson, on the other hand, have shown (Trans,, 1881, 39, 52) that this assump- tion is unwarranted, evidence deduced from other elements pointing to an alteration of atomic volume with change from single to double linking, Consequently no conclusion as to the constitution of phos- phoryl chloride can be drawn from the evidence brought forward by Thorpe.The chemical evidence, however, is altogether in favour of the symmetrical formula, and this is accepted in what follows. The problem OF the spacial configuration of the molecule of which the constitution is accepted must now be considered, and the question is whether or not the individual chlorine atoms, considered singly, are similarly situated to the rest of the molecule regarded as a whole. Whilst the chlorine atoms themselves are all alike, i t is conceivable that differences of situation, if these existed, would confer upon them different properties. identified as in the scheme Let us suppose that the chlorine atoms can be /GI, \GI, OP-CIp 0 Then any existing difference will be made manifest by substitution, for /Cia /Cia OP-Cl, , \R OP-GI, /R 9 OP--K , \c1, \C1, will all be different if all three chlorine atoms are differently situated within the molecule.Several monosubstituted derivatives have been prepared and examined with the view of discovering such isomerism if it should exist. For instance, monaniiinophosphoryl chloride, OP(NH*C,H,):C12, wasPHOSPHORYL CHLORIDE AND ITS DERIVATIVES. 1363 obtained in a yield amounting to 90 per cent. of the theoretical. This substance was fractionally recrystallised from benzene, and the melting points and crystalline characters of the successive fractions were com- pared with one another and with those of the original substance.No physical differences were detected, and so far as this evidence goes the compound may be pronounced homogeneous. The same was found to be true of mono-p-toluidinophosphoryl chloride, OP(NH*C6H,*CH,):C1,. Hence monosubstituted derivatives of phos- phoryl chloride only exist in one form. From this fact, one of two conclusions may be drawn : either (i) The single chlorine atoms are substituted indiscriminately by the reacting base, so that from different molecules either CI,, Clp, or C, may be displaced, and the result being the same, the three chlorine atoms must be similarly situated within the molecule; or (ii) A difference being supposed to exist between the chlorine atoms, the reacting base displaces from each molecule only that chlorine atom which occupies a particular position.Whilst it is probable that the first conclusion is true, it will be necessary, in view of proving the similarity of position of the three chlorine atoms, to accept the second conclusion as a working hypothesis. Thus if all the chlorine atoms were differently situated, and one of them reacted more readily with bases than the other two, the monosubstituted product would be homogeneous. Experiments were next performed with disubstituted products, the two bases aniline and p-toluidine being introduced in an order which in a second case was reversed. Thus anilino-p-toluidinophosphoryl chloride was prepared and its properties examined, and then p-toluidino-anilinophoaphoryl chloride was similarly obtained, and its physical characteristics compared with those of the first product.These two substances were thereby found t o be similar in appearance and crystalline structure j they melted a t the same temperature, and when mixed intimately the melting point of the mixture was the same as that of the constituents. Unless, therefore, differences exist which ordinary physical methods fail to detect, these two preparations are identical. Moreover, anilino-p-toluidinophosphoric acid and p-toluidinoanilino- phosphoric acid were obtained and their identity proved by the melt- ing point test. The question of the mobility of the groups within the compound, and the production of identity by intramolecular rearrangement arises here. But in bhe absence of evidence to show that substituents of such large mass as are present in the above compounds possess this mobility, the point nezd not be Further discussed.1364 CAVEN : THE MOLECULAR CONFIGURATION OF The two following types are therefore identical : and it may be concluded that the two chlorine atoms replaced from the a- and P-positions in the above reactions are similarly situated with regard to the rest of the molecule.The next inquiry has reference to the remaining chlorine atom, C1,. The method adopted consist8 in first replacing one chlorine atom, which may be supposed to be CI,, by an alcoholic residue, leaving the other two atoms to react with bases ; consequently ethoxyphosphoryl chloride was made to react with aniline, producing ethoxyanilinophosphoryl chloride, and this substance then yielded with p-toluidine a compound which is the ethyl ester of anilino-p-toluidinophosphoric acid.Thus : /O*CZW4 /0*C2H5 /0*C2H5 OP-Cl (p) + OP--NH*C6H5 + OP-NH*C,H5 (Y) \Cl \NH- C ~ H ~ . CH, In the reaction in the reverse way, ethoxy-ptoluidinophosphoryl chlor- ide and the ethyl ester of p-toluidinoanilinophosphoric acid were suc- cessively produced. Thus : /0'C2H5(a) /O0CZH5 /O* C, H, OP-C1 (p) --+ OP--NH*C,H,~CH, -+ OP-NH*C,H,*CH,. \Cl (Y) \Cl \NH-C,H, The last compound was proved by tbe melting point test to be identical with the ethyl ester of anilinop-toluidinophosphoric acid ob- tained previously. So : /RI (4 /R' (4 \RIII(Y) \El1 ( y ) OP--R11 (P) and OP-R,,,(P) are shown to be identical, and Clp and Cl, are therefore similarIy situated within the molecule POC1,. Now C1, and C1, have previously been shown to be similarly situated.Therefore, subject to the limitations referred to in the course of the above argument, the three chlorine atoms in phosphoryl chloride have been proved t o occupy similar positions in the spacial configuration of the molecule. From this fact the important conclusion follows that the five atoms of the molecule of phosphoryl chloride cannot lie in one plane; for if this were the case the central chlorine atom, in whatever angular con-PHOSPHORYL CHLORIDE AND ITS DERIVATIVES. 1365 figuration might be adopted, would necessarily occupy a unique position with reference to the oxygen atom. Thus me arrive a t the following conception for the configuration of the molecule of phosphoryl chloride : The centres of gravity of the three chlorine utorns lie at the angles of ccn eqailateral triangle; and if an imaginary line is drawn through the centre of this triangle and at right angles to i t s plane, the centres of gravity both of the phosphorus atom and of the oxygen atom are situated in this line.The question whether the phosphorus atom lies in the same pIane as the three chlorine atoms remains undecided. The configuration of the molecule of phosphoryl chloride is there- fore tet’rahedral, and differs from that of a molecule of which an atom of carbon is the centre principally in the existence of the doubly- linked oxygen atom. Compounds of the type 0 = PL-R;, , built up according t o the model ‘RIII described above, do not contain a plane of symmetry; they are 4 asymmetric ’ although containing a double linking.On theoretical grounds, it should therefore be possible to prepare optically active derivatives of phosphoryl chloride, although the presence of the oxygen atom renders it unlikely that basic derivatives of this type will be obtained. Phosphonium derivatives of the type PR,R,IR,I,R,,X, how- ever, have already been prepared by Michaelis (Annalen, 1901,315, SS), and an attempt made to resolve them, but without success. The question of the resolution of acids of the type OPR,RII*OH therefore remains to be considered. Experiments were conducted with two distinct types of compound, namely, anilino-p-toluidinophosphoric acid and methoxy-p-toluidinophosphoric acid. Alkaloidal salts of these acids were not found to be crystallisable, but bornylamine and menthyl- arnine salts were obtained and fractionally crystallised.I n no case were the different fractions found to possess different specific rotatory powers, and when the acids mere liberated from their salts they were always found to be inactive. It is intended t o pursue this investigation further, using other types of acids. Meanwhile, it may be suggested that non-activity is due to racemisation caused by the wandering of the acidic hydrogen atom in the following manner : yo\ . \OH This might take place even in aqueous solution of n salt by hydro- VOL. LXXXI, 4 Y1366 CAVEN : THE MOLECULAR CONFIGURATION OF lytic dissociation. some support to this idea of tautomeric change. substituted derivatives such as OP(NH*C,H,):Cl, and OP(NH*C6H,*C El3) :GI, may be dissolved in cold dilute potash and recovered unchanged by the addition of hydrochloric acid.This fact may be best explained by assuming that the following tautomeric change has taken place : One fact must here be referred t o which lends It is that mono- /NHR //NR \Cl ' \Cl HO*P--Cl 0:P-Cl -+- a feeble monobasic acid being thus produced which forms a salt with alkalis. If this is the true explanation of the behaviour of these compounds with alkalis, then it is the more easy to believe that a wandering of the acidic hydrogen atom may take place with disubsti- tuted acids, These considerations render it less likely that the acids of the type OPR2R,,*OH will be obtained in optically active forms. I n view of this, an attempt was made to combine menthylamine directly with methoxy-p-toluidinophosphoryl chloride, and so obtain a compound incapable of undergoing such tautomeric change. This attempt was not successful, for although reaction took place with a partial sepma- tion of menthylamine hydrochloride, no crystalline product could be isolated.E X P E R I ME NTAL, I.--Compozcnds containing Arylamino-groups. AniEinophosphoryZ Chloride, OP(NH*C6H,):C1,. This substance was obtained by A. Michaelis and Schulze (Ber., 1893, 26, 2939) by heating aniline hydrochloride on the water-bath with the theoretical quantity of phosphoryl chloride. After the evolu- tion of hydrogen chloride had ceased, a thick liquid remained from which the compound was crystallised. The method adopted in the present work', which possesses the advantage of being carried out a t atmospheric temperature, consists in slowly adding two equivalents of aniline contained in dilute benz- ene solution to one equivalent of freshly distilled phosphoryl chloride, also considerably diluted with benzene.Aniline hydrochloride at once separates in a pure white condition, and the filtrate from this, after the excess of benzene has been distilled off, yields brilliant, colourless crystals of the required derivative. The melting point of this compound is considerably affected by traces of impurity. I n the first experiments, ether was used as the solvent instead of benzene, and the product melted fairly sharply a tPEOSPHORYL CHLORIDE AND ITS DERlVATIVES. 1367 79*. This product, however, fumed in the air and was not quite pure.Michaelis and Schalze employed hot benzene and light petroleum as solvent, and obtained a product which did not fume in the air and melted a t 84'. The substance, prepared according to the method described above, was practically stable in the air and could be kept for weeks in an ordinary corked bottle without undergoing any considerable decom- position, It melted sharply a t 89- 90' after recrystallisation from benzene containing a little light petroleum. Analysis proved the compound t o be anilinophosphoryl chloride. The specimen melting at 89-90' was submitted to fractional re- crystallisation, and four successive fractions melted a t the following temperatures : 89-90', 88', 88-89', 89'. The highest melting point observed with this substance was 93-94', and this was in the case of a specimen obtained some months subsequently and crystallised from dilute solution in benzene after the addition of an equal volume of light petroleum, Under these circumstances, the compound presented the appearance of very fine, silky needles.p-Toluidinophosphoryl Chloridd, OP( NH*C,H,* CH,) : Cl,. According to Michaelis and Schulze (Zoc. cit.), this substance, prepared from p-toluidine hydrochloride and phosphoryl chloride, melts at 104'. It may be obtained in the same way as auiIinophosphory1 chloride, and when crystallised from benzene melted a t 107-108' ; fractional crystallisation from this solvent did not reveal any difference of melt- ing point. Subsequently, however, the observed melting point mas raised to 110-1 1 1' by recrystallisation from dilute solution in benzene after addition of much light petroleum.Action of Alkulis on the Monosubstituted Derivutives of Phosphoryl Chloride. Action of Ammoniu.-Michaelis and Schulze (Zoc. cit.) have observed that anilinophosphoryl chloride dissolves readily in aqueous ammonia, and they surmise that this solution contains the ammonium salt of anilinophosphoric acid. This, however, is not the case. When the ammoniacal solution is acidified with dilute hydrochloric acid, a white, scaly precipitate separates, which is shown to be anilinophosphamic acid, OP(NH*C6H,)(NH,)*OH. A quantity of this substance was obtained, washed thoroughly until free from chloride, by which means its bulk was considerably reduced, and dried, first on a tile, and then in a vacuum over sulphuric acid until its weight was constant.Analysis gave the following results : 4 ~ 21368 CAVEN : THE MOLECULAR CONFIGURATION OF 0.3878 gave 0.2500 Mg,P207. 0.1029 ,, P = 17.97. 14.3 C.C. moist nitrogen a t 11" and 746 mm. N = 16.29. Ontitration, 0.3600 neutralised20~80c.~.N/lO alkali. Mol. wt. = 173.1. C,H,O,N,P requires P = 18.02 ; N = 16.28 per cent. Mol. wt. of C,H90,N2P = 172. Anilinophosphamic acid crystallises in rhomboidal plates which are sparingly soluble in cold water and melt a t 157-158". p-~oZuidinophospi2anzic acid, OP(NH*C,H,*CH,)(NH,)~OH, may be obtained in the same way as anilinophosphamic acid by the action of aqueous ammonia on p-toluidinophosphoryl chloride and decomposition of the salt by hydrochloric acid.It is obtained in scales, or, if separated slowly by acidifying a dilute solution of its ammonium salt, in coarse prisms, and melts a t 159" : 0.4531 gave 0.2747 Mg2P207. 0.1166 ,, 15.1 C.C. moist nitrogen at 10" and 749 mm. N = 15-30. P = 16.89. C7H1,02N,P requires P = 16.67 ; N = 15.05 per cent. On titration : (i) 0.4624 neutralised 24.75 C.C. XI10 alkali. Mol. wt, = 186.8. (ii) 0,3888 ,, 20.85 C.C. N/lO ,, Mol. wt. =186*5. Action of Potash.-When either anilino- or p-toluidino-phosphoryl chloride is added little by little to an ordinary dilute solutinn of potash, the compound rapidly dissolves. If the liquid is cooled under the tap during the addition of the monosubstituted phosphoryl chloride and dilute hydrochloric acid added in excess when solution is complete, an oil is precipitated which quickly solidifies.This solid in each case was separated and crystallised from benzene with the addition of light petroleum. The product recovered from monoanilinophosphoryl chloride me1 ted at 93" ; that from monotoluidinophosphoryl chloride at 11 1-1 12'. Both substances contained chlorine, and an analysis of the former product gave the following result : C1= 33.83. C,H60NCl,P requires C1= 33.75 per cent. 3101. wt. of C7H,,02N,P =186.0. 0.2635 gave 0.3609 AgCl. It is evident therefore that the above monosubstituted phosphoryl chlorides can be dissolved in dilute potash solution and recovered unchanged by the addition of hydrochloric acid. If no precautions are taken t o cool the potash solution during the addition of the monosubstituted chloride, considerable heat is developed and the solution turns yellow.In this case, the liquid contains traces of the free base, as was proved in the case of aniline by the bleachingPHOSPHORPL CHLORIDE ASD ITS DEKlVATIVES. 1369 powder reaction. The addition of hydrochloric acid after a time causes no immediate precipitate ; it appears therefore that the monosubstituted phosphoric acids are readily soluble in water. Attempts to isolate these acids proved unsuccessful, and since partial. decomposition by potash was proved, the investigation was not carried further, Anilirzo-p-tolzlidinop~osphoryt ChZoride, OP( NH*C,H,) (NH* C6H,*CH3)C1. This substance was prepared, together with the similar substance obtained by allowing the substituents to react in reverse order, for the purpose of proving the identity of the a- and P-positions of the chlorine atoms in phosphoryl chloride.It was obtained in very fine needles which, after two recrystallisations from benzene, melted sharply at 133-134'. 0.7042 gave 0.3644 AgCl. The yield of the substance was very poor, not more than about 2 grams being obtained from 10 grams of phosphoryl chloride. After the first crop of crystals had been removed from the benzene solution, further standing produced a small crop; but soon a gummy mass separated which appeared to contain most of the material, but from which nothing was isolated at this stage. p-ToZ~id~~occnilino~~osp~o~~2/2 Chloride, On analysis : C1= 12.78. C,,H1,ON,CIP requires C1= 12.65 per cent.OP( NH* C6H4* CH3)(NH* C,H,) C1. -This compound was prepared in a similar manner to the above, and an intimate mixture of the disubstituted chlorides prepared in the two ways melted a t 133-134'. These two substances are therefore shown t o be identical. AniZino-p-toZzLi~ino~~~os~~~oiiic Acid, OP( NH. C,H,)( NH* C,H,*CH,) OH. When anilino-ptoluidinophosphoryl chloride is digested for a short time with dilute sodium carbonate solution, it is completely dissolved. No odour of aniline or p-toluidine can be detected, and after cooling and allowing to stand for some time the solution remains perfectly clear. When this clear solution is acidified with dilute hydrochloric acid, a curdy, white precipitate of anilino-p-toluidinophosphoric acid at once separates. The method of recrystallisation employed was similar to that sug- gested by Autenrieth and Rudolph (Ber., 1899,32, 2099) €or dianilino- phosphoric acid, and was as follows.The crude precipitated acid was digested on the water-bath with acetone, the hot solution filtered, and diluted with about one-fifth of its volume of water to which a few drops1370 CAVEN : THE MOLECULAR CONFIGURATION OF of strong hydrochloric acid had been added. On stirring the solution and allowing it to cool, a, good yield of crystals was obtained in the course of a few minutes. It softens at 134O, and if not quite pure melts completely, but quickly becomes solid again, and melts finally at 195-196', turning somewhat brown. Anilino-p-toluidinophosphoric acid crystallises in shining scales.On analysis of the air-dried crystallised acid : 0-2456 gave 0.1028 Mg2P207. On titration : (i) 0.4674 neutralised 18.05 C.C. 3/10 alkali. (ii) 0.3595 ,, 13-85 C.C. N/10 ,, Mol. wt. =259*6. I n connection with the possession of a dual melting point by this acid, it is interesting to notice that, according to Rudert (Ber., 1893, 26, 565) ditoluidinophosphoric acid melts at 124', but according to Autenrieth and Rudolph (Zoc. cit.) a t 195'. These later authorities attribute the low melting point observed by Rudert to his acid not being crystallised or free from water. I n order to clear up this discrepancy, a specimen of ditoluidinophos- phoric acid was prepared and crystallised from dilute acetone. It then softened at 148' and melted a t 193-194", turning brown.Dianilinophosphoric acid, on the other hand, melts, according to Michaelis and Schulze (Ber,, 1894, 2'7, 2574) a t 313", and according to Autenrieth and Rudolph (Zoc. cit.) at 214-216'. A specimen prepared and crystallised as above melted a t 213O with- out previous softening. It appears therefore that the possession of a dual melting point by two of the above disifibstitnted acids is due in some way t o the presence of a p-toluidine residue within the molecule. p-Toluidinoanilinophos~horic Acid. -This acid was prepared from phosphoryl chloride by the successive action of p-toluidine and aniline in the manner above described. The product was identical in physical properties with anilino-p-toluidinophosphoric acid, softening a t 134" and melting at 195-196'. An intimate mixture of the two substances softened a t 134" and melted at 195-1969 These two products are therefore identical.P = 11-67. C,,H,,O,N,P requires P = 1 1 *83 per cent. Mol. wt.=259. Mol. wt. of C,,H,,O,N,P = 262. II.--Compozcnds containing an Etiioxygrouy. "he purpose for which these compounds were investigated was in order that the identity of the /3- and y-positions of the chlorine atomsPEOSPHORYL CHLORIDE AND ITS DERIVATIVES. 1371 might be demonstrated, the a-position being supposed to be occupied by the ethoxy-group. Ethoxyphosphoryl chloride, OP(O*C,H5):C1, (Jcchresber., 1876, 205) formed the starting point for the preparation of the compounds described below. Ethoxyadinophosphoryl Chloride, OP(0 C,H,) (NH C6H,)C1.-This compound was prepared from ethoxyphosphoryl chloride by reaction with aniline in ethereal solution ; it crystallises in triincated pyramids and melts a t 61-629 It is much more soluble in the ordinary sol- vents than anilinophosphoryl chloride, and cannot be so easily obtained in a state of purity.0.4495 gave 002873 AgCl. C1= 15-79. C,H,lO,NCIP requires C1= 16.17 per cent. Decompo&tiort, by Wccter.-The compound was dissolved in a little alcohol, which has no perceptible action upon it, and water added to the solution, The substance separated again in the solid state, but on standing slowly dissolved. The clear solution, when evaporated over sulphuric acid a t the ordinary temperature, gave leafy crystals which were proved to be aniline hydrochloride. The following probably represents the course of the reaction with water : On analysis : /O*C,H, H,O /O*C,H5 H20 /O*C,H, \Cl \OH \OH OP-NH*C6H, -+ OP-NH*C,H, j OP-OH + HC1 + C6H,*NH2,HCl, but ethoxyanilinophosphoric acid, the intermediate product of hydro- lysis, could not be isolated.Barizcm XaZt.-This and other barium salts of disubstituted phos- phoric acids were prepared in order to furnish material for experiments on resolution in conjunction with optically active bases. Although ethoxysnilinophcsphoric acid cannot be obtained by the bydrolgeis of its chloride by water, its barium salt was prepared by the use of baryta solution. This compound, when free from barium chloride, crystallised from ethyl alcohol containing a little water in minute, slender needles which, when dry, appeared as a chalky powder.The salt thus obtained was anhydrous, and underwent no change when heated to 130°, but at a somewhat higher temperature decomposed, giving off aniline. On analysis : 0.4777 gave 0.2086 BaSO,. Ba = 25.68. 0*3616 ,, 17-2 C.C. moist nitrogen at 16' and 758 mm. N=5-53. C,H,,O,NP,Ba requires Ba = 25.57 ; N = 5-21 per cent. The amide, OP(O.C,H,)(NH*C,H,)*NH,, wcis obtained by passing1372 CAVEN : THE MOLECULAR CONFIGURATION OF dry ammonia gas into an ethereal solution of the chloride, and crystal- lised from hot water in beautiful, shining prisms melting at 127". On analysis : 0,6653 gave 0.3768 Mg2P20,. C,H,,0,N2P2 requires P = 15.50 per cent. The aqueous solution of this amide was neutral in reaction to litmus. The compound dissolved easily in warm dilute acids, but suffered decomposition in the process, the solution containing aniline and ammonium salts.P = 16-78. Ethyl anilino-p-toluidinophosphate, OP( 0 C,H,) (NH* C,H,) N HwC,H,* C H,, was prepared from ethoxyanilinophosphoryl chloride and p-toluidine. It crystallisecl from dilute alcohol in colourless needles and melted a t 11 6-1 17". On analysis : 0.4318 gave 0.1678 Mg,P20r. Ethox?l-p-toZuidinophosphory I Chloride, P= 10.83. C,,H1,0,N2P requires P = 10.69 per cent. OP(O*~,H,)(NH0~,H,*~H,)~1. -This substance crystallises in oblique prisms and melts a t 74-75". On analysis : 0.2830 gave 0.1709 AgCI. CgHl,O,NOIP requires C1= 15.20 per cent. Barium &'&-The barium salt of this acid was obtained from its chloride in a manner similar to that employed in the previous case.The salt is, however, less soluble in water than its aniline homologue, and separates during evaporation of the solution in radiating, tuft-like masses. The compound may thus be separated from the mother liquor containing the excess of barium chloride, and after three crystallisations is pure. C1= 14.92. On analysis : 0.6063 gave 0.2427 BaSO,. 0.3160 ,, 14.1 C.C. moist nitrogen a t 17" and 760 mm. N = 5 * 1 8 . The salt was also recrystallised from alcohol containing a little 0.6457 gave 0.2670 BaSO,. Ba = 24.32. Ba = 23.54. [CgH1,O,NP],Ba,H,O requires Ba = 23.55 ; N = 4.77 per cent. water, and obtained in the form of long, slender needles : [C911,30,NP],Ba requires Ba = 24.30 per cent. Thus when the least possible amount of water is used in its crystal- lisation the salt is obtained in an anhydrous state.The amide, OP(O* C,H,)(NH*C,H,*CH,)*NK,, was prepared in the same manner as the analogous aniline derivative. It was not foundPHOSPHORYL CHLORIDE AND 1TS DERIVATIVES. 1373 suitable to crystallise it from hot water, but when a mixture of ethyl acetate and light petroleum was employed, the substance separated in rhomboidal plates melting a t 125'. On analysis : 0.1726 gave 20.0 C.C. moist nitrogen at 16' and 751 mm. N=13.36. CSH150,N,P requires N = 13.09 per cent. This amide is sparingly soluble in cold and easily soluble in hot Ethyl p-toluidinoaniiinophosphate, water. Its solution is neutral in reaction. OP(O* C2H,)(NH*C,H,*CH,)*NH0C6H5, crystallised in needles from dilute alcohol. It presented the same appearance as the product described on p.1372 ; it melted a t 117'. An intimate mixture of ethyl anilino-p-toluidinophosphate and ethyl ptoluidinoanilinophosphate was made and melted a t 116-1 17'. These two products are therefore identical. II I.-C o mp o u n d s c o n t a i n i n g a M e t h ox y-g r o up. Methoxyphosphoryl Chloride, OP(O-CH,):Cl,. This simple substitution product of phosphoryl chloride appears never to have been previously prepared, although it may be obtained in the same way as the ethoxy-compound. It was found to distil at 62-64' under 15 mm. pressure. It is a colourless liquid which fumes in the air, but is not so vigorous in its reaction with water as phosphoryl chloride. For analysis, a weighed quantity was decomposed by dilute potash, the solution acidified with nitric acid was then precipitated with silver nitrate : 0.2812 gave 0.5400 AgCl.This compound cannot be distilled under atmospheric pressure. C1= 47.43. CH,02C12P requires C1= 47.65 per cent, Methoxyanilinopho~phor yl Chloride, oP( 0 cH,)(NH*C,H,)Cl. This compound was prepared by bringing together aniline and methoxyphosphoryl chloride in benzene solution. The product was found to be very soluble in benzene, and could only be obtained as a pasty mass by evaporating this solvent. A small quantity, however, was obtained in a pure condition by heating the mass with light petroleum of high boiling point and allowing the solution t o cool slowly. Methoxyanilinophosphoryl chloride cry s tallises in thick needles which melt at 82-83".It is slowly but completely dissolved1374 CAVEN : TEE MOT,ECULAR CONFIGURATION OF by dilute potash, and the solution does not give the aniline reaction with bleaching powder, N = 7.07. On analysis : 0.3258 gave 20.5 C.C. moist nitrogen at 21° and 749 mm. Barium Salt.-This salt was obtained by digesting the crude chloride with baryta solution and crystallising the product, The salt is con- siderably less soluble in water than barium chloride, from which it can easily be separated by crystallisation. It crystallises in beautiful, transparent needles quite different in appearance from either of the ethoxy-salts previously described, and the air-dried salt, when heated at looo, gives off much water. The salt contains seven mols. of water of crystallisation : C7H,02NC1P requires N = 6.81 per cent.0.3912 gave 0.1512 BaSO,. Ba=22*75. 0.2907 ,, 12.2 C.C. moist nitrogen at 23' and 763 mm. N = 4.75. [C7H90,NP],Ba,7H20 requires Ba = 23.62 ; N = 4.61 per cent. I n an attempt to estimate the water of crystallisation, 09466 gram of the salt lost 0.0418 gram at 130°, and on heating t o 155-160' for 15 mins. an additional 0,0169 gram; but in the latter case the salt turned somewhat yellow and underwent slight decomposition. If 7H20 are present, 0,2466 gram contains 0.0512 gram of water. Whilst the water cannot be directly estimated owing t o decomposition, these results confirm the previous analytical figures which indicate the presence of 7H,O in the salt. Methoxy-p-toluidi~op~osp~oryl Chloride, OP(O*CH,)( NH*C,H,*CH,)Cl.This substance, obtained by the interaction of methoxyphosphoryl chloride and p-toluidine in benzene solution, is characterised by a less degree of solubility in benzene and other organic solvents than the mixed es ter-amino-substit u t ed phosphoryl chlorides previously descri bed. It crystallises in prisms from its solution in hot benzene with the utmost ease, and can therefore be obtained pure in any desired quan- tity, and melts at 115-1169 05197 gave 0.3409 AgC1. This compound is easily soluble in dilute alkalis with the formation of the corresponding salts of methoxy-p-toluidinophosphoric acid. The barium salt is much less soluble in water than any of the barium salts previously described, and on cooling its concentrated solution separates in shining needles which, after one recrystallisation, are free from barium chloride.When the air-dried salt is gently heated, it gives off much water. On analysis : C1= 16.20. C,H,,O,NClP requires C1= 16.15 per cent.PHOSPHORYL CHLORIDE AND ITS DERIVATIVES. 1375 (i) 0.7463 gave 0.2711 BaSO,. Ba = 21.38. (ii) 1.0101 ,, 0.3644 BaSO,. Ba=21*23. (i) 0.3490 ,, 12.9 c.c.moist nitrogen at 21' and '762 mm. N =4 22. (ii) 0.41 12 ,, 15.6 C.C. ,, ,, 20.5' ,, 766 mm. N = 4.37. [C,H1,0,NP],Ba,7H,0 requires Ba = 21-62 ; N = 4.40 per cent. 0.9444 gram of the crystallised salt lost 0.1685 gram a t 130-140'. On raising the temperature further, the solid became yellow and began to decompose, This loss is 17-83 per cent., and represents a little more than 6 mols. of water. Thus the salt contains '7 mols.of water of cry stalli sa t ion, Potassium SuZt.-Some of the barium salt was decomposed in solu- tion by its equivalent of potassium sulphate. On evaporation to small bulk, the potassium salt was obtained as a mass of fine needles which are very soluble in water. Attempts to obtain the free acid from its salts were unsuccessful. IV -Attempts t o resolve Asymmetricully Xuhtitzcted Phos- p h o r i c Acids into Optically Active Constituents. Anilino-p-tolzcidinophosphoric Acid. A quantity of this acid was prepared and handed to Professor -Kipping, who tried to resolve it by forming salts with optically active bases. Bornylamine and menthylamine salts mere obtained in a crystalline form and fractionally crystallised. The acid was recovered from the various fractions by decomposing the salt with dilute mineral acid, and was examined polarimetrically. It was in all cases found to be inactive. Me thox y- p- t ol zcid inophosp h o ~ i c Acid. This acid was chosen as the most suitable of the above described ester acids because of the slight solubility of its barium salt in cold water and the comparative ease with which it can be prepared. Menthylamine Xu1t.-A sample of menthylamine, prepared from men- thone by reduction of its oxime, and which had been proved to be homo- geneous, was employed, A neutral solution of the sulphate was used to precipitate barium methoxy-p-toluidinophosphate. The precipitation was carried out a t about 6O0, and the solid which separated was very bulky in appearance, the barium sulphate having carried down with it some of the crystallised menthylamine salt, which was removed by washing with hot water, On evaporation of the neutral filtrate on the water- bath, the menthylamine salt soon began to separate in filmy t u f t s of fine needles on the surface of the liquid, and by successive removal of these by filtration, the salt could be separated into fractions. On analysis of the air-dried salt :1376 MORGAN: INFLUENCE OF SUBSTITUTION ON THE 0.5696 gave 0.1852 Mg,P,O,. P= 9.06. 0.2700 ,, 18.9 C.C. moist nitrogen at 22' and 765 urn. N = 7.99. Polarimetric examination of these fractions did not reveal any Moreover, a specimen of alkali salt recovered from a fraction of the Thus the attempt to resolve methoxy-p-toluidinophosphoric acid by C18H3303N2P requires P = 8-71 ; N = 7.87 per cent. difference of rotatory power, and their melting points were all alike. menthylamine salt was quite inactive. means of menthylamine was not successful. The author desires to thank Professor Kipping for valuable sugges- tions made especially during the earlier part of the research. UNIVERSITY COLLEGE, NOTTINGHAM.

ISSN:0368-1645    

DOI:10.1039/CT9028101362

出版商:RSC    

年代:1902

数据来源: RSC