摘要:

KARTUNG STUDIIS WITH THE MICBOBAL4XCE. PART II. 2691 CCCLXVIII.-&udies with the Microbalance. Part I I . The Photochemical Dewmposition of Silver Chloride. By ERNEST JOHANNES HARTUNG. THE investigation of the action of light on silver chloride by gravi-metric methods has not hitherto given very definite r d b . It is well known thak the halide loses chlorine and diminishes in weight when insolated but the changes are usually insignificant and afford little evidence as to the nature of the products of the action. Baker (J. 1892,61 728) tried to analyse the dark photochloride produced when 51 g. of silver chloride were insolated with repeated shaking, but only 14 mg. of chlorine were evolved after considerable exposure to light. Richardson (J. 1891 59 536) found 8% of the total halogen to be freed when 26 g.of silver chloride under water were insolated but Koch and Schrader (8. Pliysik 1921 6 127) using extremely small amounts of the dry substance could not detect greater changes in weight than 1 or 2%. A preliminary test carried out by the author with the microbalance (J. 1922,121,688) showed that a very thin film of the halide weighing 0-0880 mg. lost 81% of its total chlorine when insolated for 12 days in a vacuum. This line of attack wm therefore promising and the d h of an extended investigation tare now given. The Steele-Grant microbalanc 2692 H A R ~ G STUDIES w - r r ~ THE ~CROBALBNCE. PART n. employed carried a load of 105 mg. and was sensitive to 2 x mg. ; it was used in ideal conditions in a roomy cellar and had been thoroughly tested for 2 years.The weighings with this instrument a m recorded to the nearest 104 mg. and they are thoroughly trust-WO*~ to this degree of precision for small discrepancies in every C- where they were noted could be traced to the inevitable errors of manipulation and were never due to inaccuracy of the balance. The general plan of the work was similar to that used for the case of silver bromide (J. 1924,125,2198) ; very thin iilms of the chloride on vitreous silica sheets were sealed up in glass vessels containing suitable chlorine absorbents and insolated for defhite periods. The films were then weighed again and finally tested in various ways. Some experiments have also been made on the rate of chlbrination of thin films of silver and of the product of insolation of silver chloride.Preparation of F i l m of Pure Silver Chloride.-Films of pure silver on vitreous silica were made by chemical deposition and subsequent ignition at 4-00' as already described (h. cit.). These films were then chlorinated by exposure to dilute chlorine which was made in the usual way from manganese dioxide and hydrochloric acid, followed by washing with water and d r p g with concentrated sulphuric acid. The rate of chlorination was comparatively slow unless the gas was dilute and the weight of the resulting silver chloride usually agreed closely with that calculated from the weight of silver taken. The maximum divergence was 1 part in 24-0 parts and the average was 1 part in 1400 parts. These results are dis-tinctly leas consistent than those obtained previously with silver bromide where the maximum divergence was 1 part in 10oO parts and the average 1 part in 2400 parts.Indeed the whole process of chlorination of silver exhibited peculiarities which have not been observed in bromination. For example a certain optimum concen-tration of chlorine in mixtures with air was found at which addition of the halogen to silver occurred most easily and the speed of chlorina-tion rapidly diminished as the chlorine concentration became greater than this optimum. Also chlorine which was made from bleaching powder and dilute sulphuric acid gave chlorinated films in which the added halogen was from 3 to 4% in excess of that required to form silver chloride. The excess could be removed by cautious heating at 200" and could be prevented by igniting the chlorine before use, This pointed to some oxygen compound it8 the cause which supposi-tion was strengthened by hding that mixtures of chlorine and moist air which had stood for some days had a tendency to give slightly high results in chlorinating silver and that intermittent chlorination of silver films gave high results also.These effects were not notice m PB[OTOCHEMICAL DECOMPOSITION OF s.nm CHLORIDE. 2693 in the bromination of silver ; in any case the discrepancies are small, but their reality was established by repeated tests. Photocliemical Decomposition of Silver CMde.-The glass apparatus in which the films were sealed up and insolated was essentially similar to that used for silver bromide and has already been described.The technique adopted was similar also but great care was required to prevent contamination of the film by flame gases during the sealing for silver chloride seemed to be more sensitive in this respect than the bromide. With proper precautions, however the operation could be performed without appreciable change in weight of the h. Before exhaustion the glass vessel was filled with air nitrogen or hydrogen which had been carefully purified dried and flbred before admkaion. The final pressure in the apparatus was usually either 10 mm. or 0.001 mm. but as heating of the glass during exhaustion was inadrmss ible the latter pressure especially was not maintained over the whole period of insolation owing to the liberation of admrbed gas from the glass.For this reason the term " residual " is used in Table I to describe the conditions when the pressure of the experimental gas in the appamtus was 0.001 m. at the time of sealing off from the pump. Copper was used as chlorine absorbent but if insolation were per-formed with hydrogen present in other than residual amount solid sodium hydroxide was substituted. Insolation was performed on the roof of the laboratory and as the colour opacity and reflecting power of the h s varied steadily no estimate of the amount of radiant energy absorbed was possible. Nevertheless the times of exposure in days afford an approximate measure of the relative amounts of energy received in each case. The pearly white films always darkened rapidly to dull purple or slate which passed slowly to purple-brown; after several days this had faded to very pale greyish-yellow and no further change was visible.Meanwhile the copper in the side tube which was shielded by an opaque cover, became heavily tarnished at the nearer end and subsequent analysis showed always the presence of chlorine on it. After a definite period of exposure filtered air nitrogen or hydrogen was slowly admitted, and the film removed and weighed. The subsequent treatment varied; some of the exposed i3.m~ were rechlorinaw either in one or in several progressive operations whilsf others were used in attempts to discover the nature of the products of the phofochemical decomposition. A summary of the experimental results is shown in Table I, weights being given in milligrams.Comparison of the results in the presence of air nitrogen and hydrogen discloses a striking resemblance between them and it i 2694 €L4RTUNG STUDIES WITH THE MICROBALANCE. PART II. TABLE I. 0.2543 0.4180 0.2354 0.2428 0-3206 0-2775 0.4117 0- 1750 0.1360 0.2113 0-2634 0.1816 0-2204 0.2 108 0.2305 0.1641 0.3365 0.5556 0.3126 0.3227 0.4247 0.3690 0-5467 0.2326 0.1812 0-2809 0.3496 0.2417 0.2937 0.2808 0-3068 0.2181 0.3379 0.5554 0.3128 0.3226 0.4261 0.3688 0.547 1 0.2325 0.1807 0-2808 0-3500 0.2413 0.2929 0.2801 0.3063 0.2181 0.2899 0.4468 0.2472 0.2449 0-3432 0.2862 0-4632 0-1863 0.1406 0.2219 0.2828 0.1852 0.2375 0.2172 0.2466 0.1669 0.3362 0.3146* 0-3250* 0-3706* 0-5486 0.1829 ---- - -0-2820* 0-2 185 -56.0 2 79.1 9 84.7 11 91-1 27 78.3 10 90.5 87 61.9 87 80.4 15 89.9 88 77.5 10 94.2 62 76.7 10 90.9 91 78-9 10 94.8 111 84.4 12 * Chlorination in steps.evident that oxygen is not necessary for the photochemical decom-position of silver chloride. The experiments with air in the apparatus exhibit plainly the diminution in the speed of decomposition as the gas pressure rises due to the adverse effect of adsorbed gas h s . For nitrogen the data are insufEicient to warrant conclusions being drawn and for hydrogen the gas pressure appears to exert little influence on the change. This behaviour is not surprising for hydrogen acts as a sensitiser in virtue of its power of combining with chlorine under the influence of light.As in the case of the bromide the figures indicate that the products of the photochemical decomposition of silver chloride are silver and halogen although the final few units yo of the latter are held tenaciously in the h. There is no evidence of the formation of any sub-chloride. On rechlorinating the product of insolation colour changes were observed similar to those seen on insolation but in the reverse order. Eventually the films regained their original pearly white-ness and were then usually rather heavier than in the former un-exposed condition. This behaviour was always most marked when the chlorination had taken place in steps with interruptions for the purpose of weighing and it is believed to be due to slight oxidation during the addition of the halogen but not at other times.It was also observed to some extent when pure silver was chlorinated pro TKE PHOTOCHEMICAL DECO-MPOSITION OF SILVEB CIELOBXDE. 2695 gressively. Hence it is probable that the figures given in Table I for the percentage of chlorine lost on insolation are not appreciably affected by oxidation due to expasure to air before weighing. Chemical analysis of the insolated material would be decisive but, with less than 0-5 mg. available in each case no accurate procedure has yet been devised. Two simple methods were tried and neither proved to be quite satisfactory. In the first method the film was treated with aqueous sodium thiosulphate to dissolve any unchanged silver chloride but in spite of the greatest care insoluble particles became detached when the solution touched the film and a quanti-tative estimation was impossible.Much of the residue remained adherent to the silica however and chlorination testa proved it to be practically pure silver. In the second method the insolated film was exposed to the vapour of purified iodine at room temperature (partial pressure 0.3 mm.) in the hope that the free silver presumably present would be attacked by the iodine to form silver iodide the amount of which could be measured by the increase in weight. In principle this is obviously a more rigorous means of testing the nature of the insolated film than by chlorinating it. Unfortunately, however silver chloride itself was shown to be attacked by iodine vapour although the complete conversion into silver iodide of even very thin films of the chloride took several days.When insolated silver chloride was exposed to the iodine vapour the film rapidly darkened and then steadily changed t o the pale yellow colour of silver iodide in about 15 minutes. The first stage of the action was now taken to be complete and the film was weighed. Table I1 summarises the results weights being given in milligrams. TABLE 11. Wt. of original Wt. of insolated Wt. dtar Wt. calculated for film. an. iodination. mixed AgI and AgCI. 0-2326 0.1863 0.3646 0.3520 0.2417 0.1852 0-3898 0.3874 0.2809 0.2219 0.4338 0.4331 0-2937 0.2375 0.4489 0.4386 The weight of the iodinated film in each case is grater than that calculated on the assumption that the insolated material is a mixture of silver and unchanged silver chloride of which only the former is attacked by the iodine.In two instances the discrepancy is less than 1% and on the whole the results are favourable to the hypothesis mentioned for further iodination caused steady increase in weight in each case until after some days all the chlorine had been displaced by iodine. The method is therefore not thoroughly sound for the initial stages in the displacement of the chlorine proceed appreciably in a very few minutes and may of course b 2696 ~ " a STUDIES WITH THE MICBOBAT,ANCE. PKBT II. more rapid with previously insolated films than with pure silver chloride. Rate of CWruation of Silver Films.-Further evidence as to the nature of insolated silver chloride was obtained by comparing the rates of addition of chlorine to pure silver and to the insolated films under the same conditions.The apparatus and methods of ex-periment were essentially analogous to those used in the bromination of silver (J.y 1924,125,22O4) and have already been described. The tests were carried out in a thermostat at 25" (regulated to 0.1") with mixtures of chlorine and air in various proportions in the chlorinat-ing vessel. The concentration of the halogen was estimated by absorption in sodium hydroxide and titration in the usual way with FIG. 1. T i m of expornre in minutes. sodium thiosulphate. In every case the total area of the film was 364 sq. mm. and the average thickness 040015 mm.These results are shown graphically in Fig. 1 where the chlorine absorbed by the filmy as percentage of that necessary to form pure silver chloride in each case is plotted against total time of chlorjna,-tion in minutes. The broken lines indicate rechlorination of previ-ously insolated silver chloride films and the numbers denote chlorine concentrations in the gas phaae in mg.-atoms per litre. The curves are continuous and show no irregularities which might point to the transient formation of sub-chlorides in the film. Also the remarkable fact is disclosed that the speed of chlorination of pure silver rapidly dmumshes as the concentration of the halogen in the surrounding medium increases. This effect was not noticed in the bromination .. of silver (Zuc. cit.) but much smaller halogen concentrations were then employed owing to the very rapid attack of the silver fihw by bromine vapour. It is evident that an optimum concentrcttion must exisf at which chlorine attacks silver most readily. The precise value of this concentration has not been measured and it is hoped to investigate the whole action thoroughly in the near future. For the present purpose it was sdicient to show that isolated dver chloride h s exhibited the same behaviour a,s silver itself when exposed to chlorine. That this is so will be evident from an in-spection of the broken curves in Fig. 1 ; the existence of the optimum in this case also has beenestablished byrepeated tests and furnishes strong evidence that silver is present in the insolated material.It cannot be there in the same form aa ordinary metallic silver, however for the optimum chlorine concentration for the product of insolation is much greater than that for the metal itself whilst the whole rate of chlorination is comparatively very much slower for small concentrations of the halogen. In this respect chlorine stands in marked contrast to bromine and iodine both of which even in small concentration attack the product of insolation of silver chloride very rapidly. The work described in this paper does not contradict the conclusions of Baker (J. 1892 61 728) that perfectly dry silver chloride is unaffected by light and that perfectly dry chlorine will not attack silver. Owing to the danger of injuring the photosensitive films, it waa not possible to bake out the glass exposing vessels and the presence of phosphorus pentoxide has been found to be most objec-tionable because of the fine dust which arises from it with changes of pressure.Also in the chlorinafion experiments the halogen was '' dried " with concentrated sulphuric acid only and little alteration in the results was noted when moist chlorine was substituted for it. Summary. 1. The photochemical decomposition of silver chloride in air, nitrogen and hydrogen has been investigated by means of the microbalance. 2. The maximum percentage loss of the total chlorine in thin films of silver chloride when insolated was found to be in air 91-1% in nitrogen 89-9% and in hydrogen 94.8%. 3. Evidence is adduced to prove that the photochemical decom-position products of silver chloride are silver and chlorine and that oxygen is not necessa,ry for the action. 4. The rates of chlorination of silver and of previously insolated silver chloride have been studied and it has been shown that optimum concenbations of the halogen exist in each cam at which th 2698 MORTON AND BOQERS: chlorination is most rapid and above which the speed of reaction rapidly dimini8hes with increasing chlorine concentration. 5. No evidence of the formation of silver sub-chlorides has been found. UNlvEaSrry OF &LEOwNE. [Received June W h 1925.

ISSN:0368-1645    

DOI:10.1039/CT9252702691

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

2698 MORTON AND ROGERS: CCCLXIX.-4bsorption 8pectra and Imtam-Lacttim Tauherism. By RICHARD AIAX MORTON and EDWARD ROQEES. IT was ~bssumed by the earlier workers in absorption spectra that compounds of similar constitution would show similar absorption FIG. 1. FIG. 2. 2400 2800 3200 3600h 2400 2600 2800 3000A 6 m pi 4,000 2,000 0 - CarbostyriE. -- S-Ether. - o-Eydroryca&an$l. .... 0 -Ether. -_ N-Ether. - * - - O-Bhr. curves. Accordingly in order to decide between alternative structures of a substance it was only necessary to compare its absorption spectrum with those of two derivatives of known constitution; if the general shape of its absorption curve was similar to that of a derivative the two substances had analogous structures. In the hands of Hartley and Dobbie (J.1899,75,640) this method of interpreting absorption spectra led to conclusions in the case of lactam-lactim isomerides which are very generally quoted as establishing the value of absorption spectra in orgaaic chemistry. These workers examined isatin carbostyril and o-hydroxycarbanil together with their 0- and N-ethers; in each caSe the absorption spectrum of the parent substance resembled that of the lactam ether ABSOBPTION SPECTBA AND LA~~AM-LACTIM TAUTOMEBISM. 2699 An examination of the published curva shows that the frequencies of maximum absorption a m nearly the same for lactam and l a c k isomerides in all three cases. It is agreed by all present-day workers in the field of abrption spectra that the wave-lengtha of maximum absorption are of great importance in the inimpretation of data.Certain authorities notably Baly and Henri attach fundamental importance to these frequencies aa a basis for the interpretation of absorption spectm in terms of the quantum theory. Accordingly the f a c t thah the shape of curva is not regarded 88 a trustworthy guide to interpretation coupled with the decided advantages enjoyed by present-day workem over the pioneers in respect of tecmque made it seem worth while to repeat the work of Hartley and Dobbie. Isdin was found by Hartley and Dobbie to show two bands. Hick (this vol. p. 774) found four bands. At the time when Hicks’ paper appeared the present work had been completed and only three bands had been found. Subsequent search has not disclosed the fourth band.The three bands are at 4130A. e (max.) 625 ; 2950A., e (max.) 3,900; 2430A. e (max.) 26,000 (for graph see Hicks, loc. cit. p. 771). $-MethyZkztin (N-ether) like the went substance shows three bands at 2465A. 3OOOA. afid 41951. The curve follows that of isatin very closely. MethyZktin (0-ether) examined as soon as possible f i r preparation in the pure state shows three bands at 2447A. 2965A., 4140A. 5-Io&oisatin exists in two forms red and yellow. The red form in alcohol shom two bands 2500 and 4250A. with an inflexion near 3030A. the extinctions being 25,000 510 and 2000 (ca.), respectively. In glacial acetic acid the band at W A . was observed for the red form and an inflexion near 3000& but on account of absorption by the acetic acid the band at 2500A.could not be observed. In a fresh solution of the yellow form there is little selective absorption but after some time the bands due to the red form appear. Hicks records another band for iodoiaatin in the extreme ultra-violet. In neither isatin nor idohtin can we confirm the fourth band. A revieion of the work of Hartley and Dobbie proves disappointing, for the curves are so much alike as to preclude the possibility of deciding questions of structure from them. The absorption spectra of the isomerides are nearly identical. CarbodyriZ shows two ban& at 2690A. and 3270& e (max.) 7000 and 6750 respectively. The N-methyl ether hse bands at 2705& and 3280A. e (max.) 6600 and 6Oo0 respectively. The The curve again follows closely that of isatin curves are almost identical in agreement with the work of Hartley and Dobbie.The 0-methyl and 0-ethyl ethers are almost identical as regards absorption but me quite Werent from either the N-ether or the parent substance 0-Methyl ether 3222 and 3085A. e (max.) at 4500 and 3700 respectively; 0-ethyl ether 3226 and 3085A., e (max.) at 4500 and 3700 respectively. Both 0-ethers show a pronounced inflexion near 2650A. The analogous band in the parent substance and the N-ether has thus ma. 3. 2400 2600 2800 400 300 3 200 1oc any claim to discriminate between the alternative structures for o-hydroxgcarbanil. PWogZucid also has been examined together with its trimethyl ether. Phloroglucinol shows the following results : almost disappeared.The results confirm the wnclu-.&m of Hrtrtley and Dobbie, but the experimental basis is different since the curve for the 0-ether is different from that of these authors. o-Hydroxycurbanil shows one band with its head at 2736A. e (rnax.) 5150. The N-ether shows one band at 2738A. e (max.) 5600 and the 0-ether one at 2735& e (max.) 4700. The curves are not very Merent from those of Hartley and Dobbie. The only difference observed between these substances was in respect of the persist-ence of the bands. Revision of the work leads tn the conclusion that the curves do not warrant Solvent. hmax. emax. Solvent. hmax. emax. Alcohol ............ 2665 A 380 Aqueous metic acid 2660 A 375 Water ............... 2662 370 Alcohol with sodium Glacial acetic acid 2660 375 ethoxide .........2518 15,200 Ditto in excess...... 3472 6,60 TEYPANOCIDAL ACTION AXD ~EMICAL CONSTITUTION. PABT m. 2701 Phloroglucinol trimethyl ether shows one band at 2646& e (m.) The results me therefore in harmony with the aecepted hydroxy-465. structure of phloroglucinol. C d W . In the cwes of isatin and o-hydroxycctrbanil the work of Hartley and Dobbie is unsatisfactory. Revision shows that absorption spectra do not provide any very obvious meam of deciding the In the cases of phloroglucinol and carbostyril repetition of the work does not controvert the conclusions of these authors. It may be asserted $hat in general conclusions based on the shape of absorption curve8 need careful examination before reliance can be placed on them. Absorption spectra measurements should be interpreted by quantitative considerations concerning frequencies of maximum absorption. The present work will be discussed from this point of view at a later date. B b C t U I ' 8 . We wish to express our gratitude to Professor E. C. C. Baly F.R.S., for the interest he has taken in the work. One of us (E. R.) ia indebted to the Department of Scientific and Industrial Research for a maintenance grant. THE UNIVERSITY LIVERPOOL. [Received July 9th 1925.

ISSN:0368-1645    

DOI:10.1039/CT9252702698

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

CCCLXX. -Trypnocidal Action and Chemical Con-stitution. Part I I L Arsinic Acids Containing the Glyoxaline Nucleus. By ISIDORE ELKAXAH BALABAN and HeLaom Kma. IN Part I of this series (J. 1924 125 2595) it was shown that the three isomeric monoaminobenzoyl derivatives of 4-aminophenyl-arsinic acid showed some trypanocidal activity when tested on experimental trypanosomiasis in mice but were not permanently curative. In Part 11 (this vol. p. 2632) it was shown that per-manent curative properties appeared when a methoxy-group waa present in the para-position in the benzoyl group in the mono-aminoarsinic acids or when there were two amino-groups present, one in each nucleus. It was therefore thought of interest to prepare q1yodint?-4'(or 5')-carbox~-p-ami~henyEarsinic mid (I) and it 2702 BALABAN A?XD KING TRYPANOCIDAL ACTION 3-amino-derivative (11) both of which would resemble in build and amphoteric character the amides mentioned above.It was hoped m* As0 H /-\NH*CO-Y=$!H “H As0 H /-\NH-CO*$Z==YH N NH 2\-/ 2\-/ that the presence of the glyoxaline nucleus would lead to a more favourable-as regards the trypanocidal action4tribution of the amides in the tissues especially as the glyoxaline nucleus is con-tained in or associated with certain substances of remarkable physiological activity such as histamine insulin and the pituitary active principles. Both these arsinic acids have been prepared, the fkst by application of the Bart-Schmidt reaction to glymline-4(or 5)-curboxy-p-aminoanilide and the second by nitration and subsequent reduction of the parent arsinic acid.The maximum dose tolerated by mice and the minimum curative dose on an experimental infection of Trypmsonza equiperdum in mice expressed in milligrams per gram of mouse of these two glyoxaline arsinic acids as compared with 3‘-a&obenzoyl- and 3 3‘-diaminobenzoyl-p-aminophenylarsinic acids is shown below, Dosis toleratu ............... 1.25 3-0 0.6 >3-5 D O S ~ c~mtiva ............ 0-8 1.5 0-3 2.0 I. II. 3’-NH,. 3 3’-diNH,. ( r = 7) r signifsing the number of days the blood stream remains free from parasifes. It will. be observed that glyoxaline-4’(or 5’)-carboxy-p-aminophenylminic acid (I) unlike 3’-aminobenzoyl-p-aminophenylaminic acid has permanent curative properties and the enhanced curative properties of 3 3’-diaminobenzoyl-p-amino-pheny1a;rsinic acid are surpassed in 3-aminoglyoxaline-4’(or 5’)-carboxy-p-aminophenylarsinic acid (11).Glyoxaline-4’(or 5’)-carboxy-o-aminophenylarsinic acid isomeric with the above described para-derivative cannot be prepared by the application of the Bart-Schmidt reaction to gZyoxaZine-4(or 5 ) -carboxy-o-aminoanilide because treatment with nitrous acid gives rise to a crystalline diaxoimide (111). In the same way the amino-arsinic acid (11) gives rise In the crystalline diazoinZide (N). (G = glyoxalinyl AND CHEMICAL CONSTITUTION. PART III. 2703 Neither of these substances couples with alkaline @-naphthol; their constitution follows from the exact analogy of their formation with Biissneck’s 4-acetyl-3 Ptolylenediazoimide the constitution of which was elucidated by Morgan and Wcklethwait (J.1913, 103 1394). The diazoimide (III) is of especial interest because its formation w i l l serve to detect nitrous mid as a crgsfalline derivative a t a dilution of 1 in 6400. In the above derivatives the glyoxaline nucleus is joined to the phenyl nucleus by an amide link. The researches of +an and his amociatea have rendered available five isomeric nihphenyl-glyoxalines without an intermediate chain of atoms. These have now been reduced to the corresponding amino-derivatives- and submitted to the Bart-Schmidt process for introducing the arsinic acid group. 2-m-Aminophenylglyoxuline and 2-p-arninophenyl-glyozaline (V) so prepared give no recognisable trace of mink acids under a variety of experimental conditions.This result may be paralleled with Schmidt’s inability (Annulen, 1920 42l 168) to replace the amino-group in p-aminodiphenyl (PI) by the arsinic acid group although o-aminodiphenyl gives a 60% yield of the arsinic acid by the same reaction (Aeschlimann Lees, McCleland and Nicklln this vol. p. 68). This diiliculty in the case of substances containing the glyoxaline nucleus is clearly due to the fact that the most favourable conditions for carrying out the Bart-Schmidt reaction-neutrality or weak alkalinity-are precisely those which lead to coupling internal or otherwise of the glyoxaline nucleus present with the diazotised base. This is plainly shown in several of the cases tried by the concomitant separation of insoluble highly coloured amorphous presumably azo-compounds.The marked change of physical properties associated with N-methybtion of glyoxahes led to the preparation of 2-p-nitro-~knyl-l-methylglyoxaline with a view to its reduction and sub-seqw& tm&ment by.the Bart-Schmidt reaction. The pbor yield of monomethyla;ted product however led us t o abandon the scheme. Another avenue of approach suggested itself in the prior methylation of 2-phenylglyoxaline followed by nitration reduction and indirect amination. Here again the yield of monomethylafed product (Vn) wa only l S ~ o the main product apart from unchanged material being 2-pknyl-l -methylglyoxaline mthochlmide (VIII) 2704 B A A N AND KINQ TRYPANOCIDAL ACTION which although the salt of a quaternary base is precipitated as an oil on addition of strong alkali to its aqueous solutions.Z-P?ienyl-l-methylgZyoxaline (VII) which is also formed by dry distillation of the methochloride (VIII) under reduced pressure, forms an abnormal gold salt by crystallisation of the precipitate it yields with chloroauric acid from water containing a little acetone. The constitution of this modified gold salt RAuC13 is similar to that of several others which have been described. The two types are readily interpreted on the electronic basis. The normal salts have the structure (IX) analogous to ammonium salts whilst the abnormal have the structure (X) analogous to that of trimethyl-amine oxide. 2-o-AminophenylgZyoxaline reacts with nitrous acid with produc-tion of a crystalline tricyclic 1 2 3-triazine (XI) which does not couple with alkaline p-naphthol in exactly the same way as o-amino-phenylperimidine yields the triazine (XII) (Sachs and Steiner Ber., 1909 42 3675)./-\ ":N 4 -p - Amimphen y Zgly oxaline submitted to the Bart - Sc hmidt reac -tion yields a very small amount of 4-phenyEgZyo~Zine-p-arsinic acid, the main product being a purple dyestuff. The arsinic acid was not obtained in sufEcient quantity for trial on experimental trypano-somiasis. This was unfortunate as its structure (XIII) bears a close resemblance to the pyrazolone (XIV) derivatives of which are at present on the market for the treatment of protozoal diseases. (=.I (m.) The isomeric 4-o-amimphenylgZyoxaZine on diazotisation yields a non-coupling yellow triazine structurally related to (XI).The chief interest however in 4-o-aminophenylglyoxaline lay in the remote possibility of its resolution into enantiomorphs. Pyman has produced a considerable body of evidence for the resemblance between glyoxaline and benzene so that the substance under con-sideration being related to diphenyl should if Kaufler's ideas b AND CaEMltCAL CONSTITUTION. PABT Ill. 2705 applied to it be resolvable. The other type of formula the non-coplanar type suggested by Kenner as an explanation to be con-sidered in the interpretation of his results would in the present instance not lead to enantiomorphs. 4-o- Aminophenylglyoxaline has been fractionally crystallised from water a t low temperatures as its nomnal d-tartrate and as its dimmphor-lO-sulphte but in neither case was there any evidence of resolution.Several attempts have been made under a variety of conditions to introduce arsenic directly into the glyoxaline nucleus but hitherto unsuccessfully. The Bkhamp reaction (heating with arsenic acid) has been applied to glyoxaline 1 -methylglyoxaline 2-phenyl- and 4-phenyl-glyoxalines whilst the action of arsenious chloride with or without addition of aluminium chloride has been examined on glyoxaline 1 -methylglyoxaline and 4-phenylglyoxaline. We are much indebted to Miss F. M. Durham and Miss J. Marchal for the care exhibited in determining the therapeutic action of the arsinic acids herein described and to Prof. Pyman not only for freely allowing us to work in this field and for placing at our service unpublished results which materially assisted the investigation but also for a gift of 4-o-nitrophenylglyoxaline.E x P E R I M E N T A L . Nitration of Glyoxaline-4(or 5)-carboxyanilide.-The nitrate separating from water is dimorphous both forms crystallking with +H,O (a) unstable flu@ needles loss at 100" = 4.3; (b) stable, stout prisms m. p. 170-171" (decomp.) loss a t 100" = 3.4: Theory for *H20 = 3.5%. Found in dry salt by nitron estimation, HNO, 25.1 (Theory requires €€NO, 25.2%). The nitrate (75 g.) was added gradually and with ice-cooling to 150 C.C. of concentrated sulphuric acid. The product was kept for 3 hours at room tem-perature and then poured into ice-water ; the solid obtained (55.5 g.), m. p. 265" (decomp.) recrystallised twice from 700 C.C.of N-hydro-chloric acid gave 33.8 g. of glyodine-4(or 5)-carboxy-p-nitroaniZ& hydrochloride. A further 4-7 g. were obtained from the mother-liquors. The.sulphuric acid mother-liquors were heated a t 80" and frac-tionally precipitated by addition of sufficient strong alkali to produce a slight separation of solid from the hot solution and copious crystailisation when cold. The process was repeated until all acidity waa removed final neutralisation being effected by saturated sodium carbonate. Several crops of almost pure glyomline-4(or 5)-curboxy-o-nitroanilide m. p. 229" were thus obtained. This was finally purified aa hydrochloride. The h a 1 mother-liquors of the fractionation gave 1-0 g. of p-nitroaniline (m. p. 147"). VOL.CXXVIT. 4 2706 BAIABAN AND KING TRYPANOCIDAL ACTION In all 38.5 g. of the pisomeride and 15.4 g. of the o-isomeride were obtained in a pure state as hydrochlorides yields of 36 and 14.3% respectively. Gl yo~aZi~~-4( or 5) -curbox y - p-nitroanilide hydrochloride mono-hydrate crystallises from N-hydrochloric acid in which it is sparingly soluble in long colourless rectangular prisms or tablets decomposing about 298". It also crystallises in f l u e needles which on standing in contact with the solution pass into the previously described stable variety (Found loss a t 95" 1.9; C1 12.4. CloHs0,~,,HCl,H20 requires C1 12.4%. When dried a t 110" the salt suffers complete loss of water and partial loss of hydrogen chloride. Found: loss 7.4; C1 12.1. The monohydrate requires H20 6.3%.ClJIsO~4,HCI requires CI 13.2%). The base crystallises from glacial acetic acid in long colourless plates m. p. 307" (COIT.) which contain two mols. of acetic acid (Found loss a t 95" 37.1; on dried solid C 51.7; H 3-5. cloHso,N4,2c2~402 requires loss 34-1 %. C10HS03NP requires C 51.7; H 3-4y0). It is practically insoluble in water and the usual organic solvents except acetic acid. It dissolves in 2N-sodium hydroxide with a pale yellow colour and is reprecipitated by carbon dioxide. It forms a sparingly soluble nitrate m. p. 205" (decomp.). Glyoxaline-4(or 5)-carboxy-o-nitronilide crystallises from glacial acetic acid in bright yellow glistening plates m. p. 229" (Found : C 51.3; H 3.5. C10H,03N4 requires C 51.7; H 3.4%). It is practically insoluble in water and the usual organic solvents except acetic acid.In 2N-sodium hydroxide it dissolves with an intense yellow colour and is precipitated by carbon dioxide as glistening, yellow needles. The nitrate from 2N-nitric acid crystallises in long y~llow prisms m. p. 196" (decomp.). The hydrochloride crysfalhes from N-hydrochloric acid in which it is moderately easily soluble in yellow rectangular? anhydrous prisms (Found : c1 13.0. Hydrolysis of the Nitro-wmpoud.-2.0 Grams of each hydro-chloride were boiled for 3 hours with 20 C.C. of 16% hydrochloric acid. Extraction with ether isolated p - and o-nitroaniline respec-tively? which were identified by the melting points of mixtures with authentic specimens. The mother-liquors were partly basified ; glyoxaline-4(or 5)-carboxylic acid was then isolated effervescing a t 275" (alone or mixed with an authentic specimen).Glyoxuline-4 (or 5) -carboxy - p -aminoanilide Dih ydrochloride. -Twelve grams of the hydrochloride of the p-nitroanilide were added to a mixture of 75 C.C. of concentrated hydrochloric acid and 75 C.C. of alcohol containing 30 g. of hydrated stannous chloride in solution. On heating at 80" a bulky pale yellow precipitate separated? which CloHsO,N,,HCl requires c1 13.2%) AND CHEMICAL CONSTITUTION. PART III. 2707 dissolved on addition of more alcohol. On cooling 15.6 g . of the sttznnichloride of the amino-base m. p. 290" (decomp.) separated, and a further 2-3 g. on concentration of the mother-liquors. After removal of tin as sulphide the dihydrochZur& of the base 9-55 g.or 80% of theory was isolated. This salt crystallises from dilute hydrochloric acid in colourlw glistening rectangular prism which blacken a t about 290" and crystallise with one molecule of water (Found loss 6.1 ; on anhydrous salt Cl 25.9. Cl,,HloON4,2HC1,~0 requires H,O 6-1 %. CloH100N4,2HCl requires C1 254%). The diazotised salt couples with alkaline @-naphthol with production of a red solution. The base is precipitated by addition of sodium carbonate solution. It is moderately soluble in water and crystal-lises in colourless glistening delicate plates m. p. 228". The picrate crystallises in long h e yellow needles darkening a t 256" and decomposing a t 266" and is very sparingly soluble in boiling water (Found K O 5.7; on hied salt picric acid estimated by nitron 53.0.CloHloON4,C,H,07N3 1&H,O requires q0 5-9 %. CloHloON4,C,H307N3 requires picric acid 53-1 %). C1yom~ine-4(or 5)-mrboxy-o-aminoanilide DihydrocUoride.4i.x grams of the hydrochloride of the nitroanilide were reduced in the same way as the p-nitroanilide. On keeping the stannkhloride (11.0 g.) separated in colourless rectangular prisms and on con-centration another 2-0 g . were obtained. On removal of tin as sulphide and concentration to a low bulk glyoxalinecarbozy-o-aminoanilide &hydrochloride crystallised out (yield 5-4 g. or 87.5%). This salt crystallises from dilute hydrochloric acid in long, rectangular prisms which decompose at 310" and crystallise with one-half a mo.2ecule of water (Found loss a t loo" 3.6.Cl,,H,,0N4,2HC1,~H,0 requires H,O 3.2%. Found on dried salt C1 25.5. Cl,€€l,0N4,2HC1 requires C1 25.8%). It is very readily soluble in water and on addition of sodium nitrite a diazo-imide (111) crystallises out. This is sparingly soluble in boiling acetic acid ethyl alcohol or benzene somewhat more readily soluble in boilmg methyl alcohol from which it separates in fine needles, m. p. 195-196" but varying with the rate of heating. The diazo-imide is soluble in sodium hydroxide solution but not in sodium carbonate and forms an insoluble hydrochloride with concentrated hydrochloric acid but dissolves on dilution. It produces no colour on addition to alkaline /%naphthol solution. It is very sparingly soluble in water and will detect nitrous acid as a solid crystalline derivative a t a dilution of 1 in 6400 in the presence of sodium acetate or conversely the anilide can be detected a t a dilution of 1 in 5OOO.The amino-base is precipitated on careful addition of sodium 4x 2708 B U B B N AND KING TRYPANOCIDILL ACTION carbonate to the dihydrochloride. It is moderately easily soluble in boiling water and crystallises in h e needles m. p. 270" with previous darkening. The dipicrate is very sparingly soluble in boiling water and crystallises in minute needles m. p. 242" (decomp.) (Found H,O 5.9 5.6; on drid-Balt picric acid 70.8 71.0. Cl,,E,,0N,,2C,H30,N3,2~€&0 requires H,O 5-8 %. requires picric acid 69.4%). Glyoxaline-4'(or 5')-carboxy-p-aminophenylarsinic Acid (I).-Gly-oxalinecarboxy-p-aminoanilide dihydrochloride (27.3 g.) (in 5 batches) was dissolved in 150 C.C.of water cooled to 0" and diazo-tised by addition of 100 C.C. of 10% sodium nitrite solution. To the clear solution 9.0 g. of arsenious oxide in 70 C.C. of 2N-sodium hydroxide were added to produce a faintly alkaline reaction. A light brown precipitate separated and a considerable amount of frothing took place. After keeping over-night the solution was w-armed on the water-bath and filtered from coloured by-products. The filtrate was fractionally precipitated with strong hydrochloric acid and after removal of amorphous material a crystalline crop separated. On keeping 11.2 g. (36% yield) of crude arsinic acid were obtained. It crystallised from 75% acetic acid (50 vols.) in pale yellow glistening triangular leaflets which darkened at 280".This acid is almost insoluble in boiling water or glacial acetic acid, dissolves more readily in mixtures but is readily soluble in boiling 25% formic acid separating in needles forming a very stable monohydrate (Found on various samples loss a t 105" 0.7; As, 22.4 22.4 22.8. C10H100,N3As,H,0 requires As 22.8%). A 1% solution in 0-2N-ammonia treated with a tenth of its volume of 5% magnesium or calcium chloride gave an immediate precipitate of the magnesium salt in h e needles but the calcium salt separated in anisotropic spheroids only on heating. The sodium salt crystal-lises in needles and the hydrochloride in fine needles. Glyoxaline-4'(or 5')-carboxy-p-amino-3-nitrophenylarsinic Acid.-Glyoxalinecarboxy-p-aminophenylarsinic acid (9.9 g.) was dissolved in 30 c.c of sulphuric acid a t 0" and nitrated by addition of 3.g. of nitric acid (d 1-42) dissolved in a few C.C. of sulphuric acid. When the mixture was poured on to ice the crude nitro-acid (10.5 g.) separated a t first in leaflets but later in needles. The mother-liquors neutralised to Congo-paper and kept at 0" for 3 days, deposited a further 2-0 g . of nitro-acid. The pure nitro-acid is best obtained by crystallisation from 50% acetic acid. It is almost insoluble in boiling water or boiling glacial acetic acid. From 25% formic acid it separates in clusters of yellow plates m. p. about 327" (decomp.). It forms a very stable monohydrate (Found: C10H100N4~2C6H307N AND CHEMICAL CONSTITUTION. PART III.2709 lorn a t 110" 0.9; on two distinct samples of dried acid As = 19-8, 19.9. C1,€&0,N4~,H,0 requires As 20-O~o). 1% Solutions in O.2N-ammonia were treated with a tenth of the volume of 5% lithium magnesium calcium or barium chloride ; a micro-crystalline precipitate of the magnesium salt formed immediately the calcium salt separated almost immediately in fine needles and the barium salt also in fine needles especially on rubbing the walls of the vessel. The lithium salt separated after keeping for several days. Hydrolysis of the Nitro-aci&.-'P,o grams of the pure acid were boiled for 30 minutes with 30 C.C. of N-sodium hydroxide and the solution was cooled and made neutral to Congo-paper. Successive crops of acids were obtained which by suitable crystallisation from water gave eventually an 86 yo yield of 3-nitro-4-aminophenylarsinic acid and an 83% yield of glyoxalinecarboxylic acid.There was no evidence for the presence of isomeric nitro-acids and no definite evidence was obtained from fractional crystallisation of 10 g. of crude glyoxalinecarboxy-p-aminonitrophenylarsiic acid. Glyomline-4'( or 5 ') -carboxy-p-amino-3-aminophenyZarsinic acid (11) was prepared by dissolving 8.0 g. of the nitro-acid in 80 C.C. of 2N-sodium hydroxide at - 5" adding gradually 28 g. (7 mols.) of ferrous chloride in 40 C.C. of water and and finally 80 C.C. of 2N-sodium hydroxide. After filtration the ferric hydroxide was extracted thrice with 150 C.C. of 0-2N-sodium hydroxide. The combined filtrates were neutralised to Congo-paper and the crude amino-acid (5.65 g.) which separated crystalline was collected.The mother-liquors were made alkaline with ammonia and heated with magnesium chloride. The magnesium salt which separated was dissolved in 50 C.C. of N-hydrochloric acid and the acidity removed by sodium acetate. The amino-acid so obtained weighed 0.85 g. The total yield of crude amino-acid was 86%. It was purified with diEculty by dissolving in 0-527-hydrochloric acid and cautiously adding saturated sodium acetate solution until the solution was only faintly acid to Congo-paper. This caused the gradual separation of a green flocculent substance which could be filtered off; the amino-acid was precipitated from the filtrate by further addition of sodium acetate. The pure amino-acid crystal-lises in h e long colourless rectangular prisms which are unmelted a t 320".They contain half a molecule of water not lost a t 100" (Found As 22.4 22.2. Cl0HllO4N4As,#&O requires As 22.4%). In hydrochloric acid solution addition of sodium nitrite causes an immediate precipitation of a crystalline diazoimide (IV) which separates from dilute solutions in microscopic leaflets. The diazo-imide does not couple with p-naphthol. A 1% solution of the amino-acid in 0-227-ammonia treated with one-tenth its volume o 2710 BALABAN AND KING TRYPANOCIDAL ACTION 5% magnesium or calcium chloride gave an immediate precipitate of the magnesium salt in fine needles whilst the calcium salt was precipitated in crystalline tufts only on 'heating. 2-p-Aminophenylglyoxline dihydrochloride (V) was obtained by reducing 19.0 g.of 2-p-nitrophenylglyoxaline with 68 g. of stannous chloride in 170 C.C. of concentrated hydrochloric acid. The stunni-chloride separated in colourless needles after digestion on the water-bath. Its de-tinned solution on concentration gave 16.2 g. of the pure dihydrochloride crystallking in colourless rectangular prisms which darken at about 300" (Found C1,30.5. Cg€&N,,2HCI requires C1 30.6%). It diazotises and couples with alkaline B-naphthol forming a deep red solution and also gives an intense red solution with Pauly's reagent. The free base is an oil which turns brown on exposure to air The monopicrate is very sparingly soluble in water and crystallises in orange glistening rectangular plates decomp.about 238" (Found picric acid by nitron 58.7. C,HgN3,C6H,0,N3 requires picric acid 59-Oy0). Under no con-ditions could any arsinic acid be isolated by the application of the Bart reaction to this aminophenylglyoxaline. Action of Methyl Sulphate on 2-p-hTitrophenylglyoxaline.-The base (12.6 g.) was heated a t 100" with 8.4 C.C. of methyl sulphate for 1 hour. After initial liquefaction the product set to a cake. The solid obtained on treatment with sodium hydroxide was crystal-lised as hydrochloride; 6.0 g. of the hydrochloride of the initial material were recovered. The hydrochloride mother-liquors on being basified gave 1.0 g. m. p. below 120". This was 2-p-nitro-phenyl-1 -mthylglpoxaZine and when recrystallised from water it separated in long pale yellow silky needles m.p. 116.5" (corr.). It is moderately soluble in boiling water sparingly so in ether and very soluble in alcohol benzene or chloroform. The chlorouurute crystallises from 3N-hydrochloric acid in golden-yellow irregular prisms which decompose a t 226" (corr.). It is soluble to the extent of 1 in 300 in the boiling acid (Found Au 36-4. C,,H90,N3,HAuC14 requires Au 36.3%). The hydrochloride crystallises in elongated plates and is very soluble in water. The nitrate crystallises in diamond-shaped plates effervescing at 186" (corr.). It is moderately soluble in water but sparingly soluble in dilute nitric acid. The picrate crystallises from alcohol in which it is very sparingly soluble in fine glistening needles m. p. 212" (corn.) (Found: picnc acid by nitron 53-1.CI,Hg0,N,,C6H,0,N3 requires picnc acid 53.0 yo). 2-m-Aminophenylglyoxaline dihydrochloride was obtained by reducing 7-0 g. of the m-nitrophenylglyoxaline with 25 g. of stannous chloride in 64 C.C. of concentrated hydrochloric acid and 30 C.C. o AXD CHEMICAL CONST~UTION. PABT ITI. 2711 alcohol on the water-bath. When cold the stannichloride separatd in rectangular prisms which after de-tinning and concentration, gave 6-2 g. of the pure dihydrochloride. This salt is a numohydrate and melts with decomposition a t 282". It is very solubJe in water, less soluble in acid solutions (Found loss 7-3; on dried salt, C1 30.5. C,€&,N3,ZHC1,H,0 requires H,O 7.3%. C,€&N3,2ECl requires C1 30.6%). After diazotisation it couples with alkaline p-naphthol with an intense red colour.The base liberated by addition of sodium bicarbonate is very soluble in water. It is a monohydrate which partly melts with effervescence between 130 and 140" and finally melts at 202-203". When dried at 95" it melts a t 203-204" (Found loss a t 95" 9.1. C,H,N,,H,O requires H,O 10.2%). The anhydrous base is sparingly soluble in boiling acetone benzene or ethyl acetate and readily soluble in hot alcohol, from which it crystallises in h e needles. The monopicrate crystal-lises from water in which it is very sparingly soluble in long spikes, decomp. 218" (Found picric acid by nitron 58-0. c,&N3,c6H30,N, requires picric acid 59.0%). Attempts to replace the amino-group in this base by the arsinic acid group by the Bart reaction were all unsuccessful.~-o-Aminophenylglyo~line dihydrochloride was prepared from the nitro-compound by reduction with stannous chloride the stunnichluride separating in thin plates. The dihydrochloride (Found: C1 30-5. C$BP3,2HC1 requires C1 30.5%) crystallised in large, glassy tablets melting at 234-236" and decomposing a few degrees higher. It was readily soluble in water and on addition of sodium nitrite gave a triazine (XI) crystallising in needles m. p. 113-114". This triazine is insoluble in alkali but immediately soluble in concentrated hydrochloric acid. From 3N-hydrochloric acid the hydrochloride of the triazine crystallises in needles. The triazine does not couple with alkaline p-naphthol. The nzmmpicrute of the o-base is readily soluble in boiling water and crystallises in small, feathery needles m.p. 211-2112' (without decomp.) (Found: picric acid 59-6. C,H,N3,C6H,0,N3 requires picric acid 59.0y0). The base melts at 136-137" and crystallises from water in large, white fern-like crystals. 4-p- Aminophenylglyoxuline dihydrochhde was prepared by reduc-ing the p-nitro-base (19 g.) by 68 g. of stannous chloride in 170 G.C. of concentrated hydrochloric acid and 50 C.C. of alcohol on the water-bath a t 80". The &unnichluride (needles darkening a t 310") crystal-lised from the hot solution. After removal of tin as sulphide, 17.1 g . of pure dihydrochloride were obtained in colourless glistening needles which darken a t 310" (Found C1 30.5. C,v3,2HCl requires C1 30.6%). It is readily soluble in water and whe 2712 BALABAN AND KING TRYPANOCIDAL ACTION diazotised gives with alkaline p-naphthol an intense purple dye; but a similar colour is obtained with the diazotised base and sodium hydroxide alone.It gives an intense red colour with Pauly's reagent. The base crystallises from water in which it is moderately soluble in glistening hexagonal plates m.p. 98" (corn.). The dipicrate crystallises from water in which it is very sparingly soluble, in yellow needles m. p. 240" (decomp.) (Found picric acid 73-9. C,v3,2C,H30,N3 requires picric acid 74.2 yo). GlyomZine4(or 5)-phenyZ-p-arsinic acid (XIII) was obtained by addition of sodium nitrite to 4-p-aminophenylglyoxaline dihydro-chloride (10 g.) at 0" and subsequent addition of 6.6 g. of arsenious oxide in 36 C.C.of 2N-sodium hydroxide. An intense dark purple solution was formed but the reaction of the solution could be adjusted to neutrality by use of glazed litmus paper. When the evolution of nitrogen had ceased the solution was warmed on the water-bath and the insoluble dyestuff filtered off. The solution was made neutral to Congo-paper and after removal of amorphous material was concentrated. The arsinic acid separated in reddish-yellow plates which were unmelted a t 310" (yield 0.5 g.). On crystallisation from glacial acetic acid,dt separated in dense yellowish-brown prisms. The amount of material was insufficient for analysis but served to confirm its identity. Further experiments under a variety of conditions resulted in no improvement of the yield.This acid gave an intense reaction with Pauly's reagent. Its ammoniacal solution gave an amorphous magnesium salt on heating but the calcium salt separated in the cold in sphaero-crystals. The barium and lithium salts were soluble. From alkaline solutions the acid is precipitated by addition of mineral acid in colourless elongated leaflets. 4-o-Aminophenylglyoxaline dihydrochloride was obtained by reduc-tion of the nitro-base by stannous chloride in concentrated hydro-chloric acid. On removal of tin and concentration the dihydro-chloride monohydrate separated in colourless prisms which effervesce a t 256" and do not lose the water of crystallisation at 95" (Found : C1 29.1 29.1. C,&N3,2HC1,H,0 requires C1 29.2%). It is very soluble in water and with sodium nitrite gives a bright yellow solution from which the triazine separates in clusters of microscopic needles.It does not couple with alkaline p-naphthol and is not soluble in alkali. The base separates as an oil on addition of sodium hydroxide but a slight excess of sodium bicarbonate causes it to crystallise in square plates m. p. 131". It is soluble in water, sparingly soluble in ether and is unaffected by excess of sodium hydroxide. The dipicrute crystallises in elongated plates from water in which it is sparingly soluble and decomposes about 200 BND CHXMICAL CONSTITUTION. PABT III. 2713 (Found picric acid by nitron 73.5. C&&N3,2C6H30,N3 picric acid 74.2%). The wmal tartrate sepamtes in felted needles from aqueous solutions containing molecular proportions of the constituents or one molecular proportion excess of tartaric acid.Repeated crystallisation a t temperatures below 40" failed to effect any change in its rotation or melting point. It crystallises with 1.5H20 and loses 1€&0 in a vacuum over sulphuric acid. When air-dried or dried in a vacuum it melts at 95-97" and then effer-vesce~ a t about 130" [Found loss in a vacuum 5.3; on vacuum-dried material c 49.1; H 5.1. (for loss of 1H20) H,O 5.4%. C,H9N3,C4H606,~H20 requires C 49.1 ; H 5-1%]. The specific rotation was determined in water : c = 0.914; 1 = 2 ; a + 0-27"; + 14.8". The di-d-cumphor-lO-sulphonate is readily soluble in water from which it crystallise~ in anhydrous needles m. p. 198-200" (Found S 10.1. C&&N3,2CloH,,04S requires S 10.0%).The rotation was un-changed after recrystallisation from water below 40" c = 1.0; 1 = 2; a + 0.4Z8"; [a]5461 = + 21.4" c = 2-04; 1 = 2; a + 0.868"; [a]sa61 = $7 21.3"; whence [MI,, = 133.1". Graham (J. 1912,101 747) gives for the molecular rotation of the camphor-sulphonic ion = 66-5; whence for two ions = 133.0" a value identical with that observed for the above salt. Methylation of 2-PhenylgZyoxaline.-Methyl sulphate (28 c.c.) was added in small quantities to 40 g. of 2-phenylglyoxaline with cooling. A vigorous reaction ensued and the mass liquefied. After heating for 30 minutes on the water-bath the product was treated with 20 C.C. of water and mixed with sodium nitrate and nitric acid. On concentration an oily layer separated which deposited 11.2 g.of a nitrate m. p. 126"; this on recrystallisation gave eventually 8.5 g. of unchanged 2-phenylglyoxaline and from its mother-liquors 1.3 g. of 2-phenylglyoxaline picrate m. p. 234" and 1.0 g. of a new picrate m. p. 132". The original nitrate mother-liquors were concentrated further made alkaline with sodium hydroxide, and extracted with chloroform. The chloroform was extracted twice with water ; the aqueous solution on evaporation with hydro-chloric acid gave 15.5 g. of 2-phenyl-l-met~y~lyomline metho-chloride (VIII). The chloroform extract distilled a t 20 mm., gave 9-4 g. of an oil b. p. 190" from which alcoholic picric acid produced 27 g. of picrate m. p. 124". On recrystallisation from water 19.2 g. of 2-phenyl-1-methylglyomline picrate m.p. 132", were obtained and from the mother-liquors 1.6 g. of 2-phenyl-glyoxaline picrate m. p. 232" with various small crops of mixed picrates. 2-Phenylglyoxaline 2-phenyl-1 -methyIglyoxaline and C,~N3,C,H606,1~H20 4 x 2714 TBYPANOCLD~~ ACTION AND cmauc~z~ CONSTITUTION. PUT m. 2-phenyl-1 -methylglyoxaline methochloride were obtained in yields of 32.3 18.2 and 26.7% respectively. 2-Phenyl-l-methylg2yowlline (VII) is a viscous pale yellow oil, b. p. 175'115 mm. with a strong but not unpleasant odour. It is not soluble in water but soluble in organic solvents. The chloro-aurate is practically insoluble in water alcohol or 3N-hydrochloric acid but can be recrystallised from the first-named by addition of a little acetone. It separates in deep yellow elongated prisms, m.p. 189" (con.) (Found Au 42.8. CloHl,,N2,AuC13 requires Au 42.7%). The nitrate is a very soluble salt crystallising in needles m. p. about 100". The picrate separates from 60 parts of boiling water in glistening elongated plates m. p. 133" (corr.). It dissolves three times as readily in boiling alcohol (Found picric acid 59.3. CloHl,,N2,C,H30,N3 requires picric acid 59.2 %). The hydrochloride is extremely readily soluble in water or alcohol and separates in needles (Found loss in a vacuum 14.9; on dried material C1 18.4. CloH,,,N,,HCl,2H20 requires H,O 15.6%. Cl&Xl$2,HC1 requires C1 18.2%). The hydrogen omlate crystal-lises from alcohol in colourless long needles m. p. 135" (corr.). It is readily soluble in water and hot alcohol [Found N 11.0 (Kjeldahl). Cl,Hl~2,C2H20 requires N 11-3%]. 2-Phenyl-1 -methylglyomline methochloride was obtained in small, very hygroscopic needles m. p. 272" by dissolution in absolute alcohol and addition of ether (Found H 6.2; N 13.7; C1 16.7. CloH,,,N2,CH3C1 requires H 6.2 ; N 13.4 ; C1 17.0%). On addition of strong alkali to an aqueous solution the quaternary base is precipitated as an oil. The chloroaurate crystallises from dilute hydrochloric acid in which it is very sparingly soluble in pale yellow elongated leaflets m. p. 134" (corr.) (Found Au 38.5. CllH13N2,AuC14 requires Au 38.5%). Distillation of 2-Phenyl-1 -methylglyoxaline Methmhloride.-Five grams of this salt were distilled a t 15 mm. 2-Phenyl-l-methyl-glyoxaline distilled over a t 175" in 56% yield. It was converted into the picrate m. p. 132" and proved to be identical with that described above. We are indebted to Mr. W. Anslow for the majority of the analyses THE NATIONAL h s m m FOR MEDICAL RESEARCH, recorded in this paper. HAXPSTEAD N.W. 3. [Received September 15th 1925.

ISSN:0368-1645    

DOI:10.1039/CT9252702701

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

RATE OF REACTION OF BROMINE WITH AQUEOUS FOBMIO ACID. 2715 CCCLXX1.-The Bate of Reaction of Bromine with Aqueous Formic Acid. By DALZIEL ~ W E L L Y N HAMMICK W- KENNETH HUTCHISON, FORMIC acid in aqueous solution is oxidised by each of the halogens to carbon dioxide and halogen acid the reactions in the cases of bromine and iodine proceeding a t rates that make velocity measure-ments possible. An account is now given of a study of the kinetics of the oxidation by bromine. Somewhat similar reactions have been studied by Bugarsky (2. physikul. Chem. 1901 38 561; 1904 48 63) who recognised clearly the disturbing effects due to the products of the reaction to which effects further reference will be made. That the reaction goes to completion in accordance with the equation HC0,H + Br = 2HBr + CO was established in the following manner.A strong solution of bromine in water was contained in an apparatus as described by Richards (ibid. 1902, 41 544) which delivered bromine solution of constant strength. The amount of bromine in one measure (about 15 c.c.) was estimated iodometrically. A mixture of exactly 20 C.C. of a solution of formic acid of known strength 4 measures of bromine water and 20 C.C. of approx. N-hydrobromic acid was kept in a thermostat a t 25" for 3 days. By estimating the residual bromine it was found that 2.23 g.-mols. of formic acid react with 2-24 g.-mols. of bromine. Materials and Nethod.-The bromine prepared from pure potassium bromide contained 99.6% Br and no detectable iodine. The anhydrous formic acid contained 99.7% HC0,H.A Jena glass flask of about 450 C.C. capacity with a narrow neck and ground glass stopper was used as the reaction vessel placed in a thermostat a t 25-00' -J- 0.04". The initial volume of reaction mixture was always 400 C.C. Preliminary experiments established the following points (1) Under the conditions of working light has no appreciable effect on the rate of reaction. (2) The rate of reaction is greatly diminished by the presence of hydrogen- or bromine-ion. Experiments were therefore made to determine the rate of dis-appearance of bromine in solutions containing excess of both formic acid and hydrobromic acid. Quantities of 25 C.C. of the reaction mixture were withdrawn at measured times and discharged into potassium iodide solution.The iodine liberated was then titrated with standard thiosulphate. In all these experiments the titration of the initial quantity of bromine was carried out under similar and FREDERICK ROWLBNDSON S N ~ . 4x* 2716 HAMMICK HUTCHISON AND SNEU THE RATE OF conditions of acidity. But no attempt was made to neutralise the excess of acid in the titrations since the form of the monomolecular velocity coefficient ensures that any proportional error in the titration will be eliminated. Table I shows that the rate of disappearance of bromine follows the monomolecular law k = 2*303/t . log @/(a - z)) where a is the initial titre equivalent to 25 C.C. of reaction mixture and (a - z) is the titre a t time t (mins.). A zero time correction was introduced owing to the time of mixing being rather long compared with the time of reaction.This correction obtained by plotting values of log @/(a - z)} against t and extrapolating back to zero was never very large being generally of the order of - 0-1 min. All the values of k have been computed after the addition or subtraction of the necessary correction thus obtained. TABLE I. CHB~ C H ~ E and initial concentration of bromine = 0.1665 0.278 and 0-0108 g.-mol. per litre respectively. t ............... 0.00 1.82 3.30 4.32 5.68 7.30 11.80 Br titre (c.c.) 27.12 18.69 13-32 10-81 8-18 5-82 2.40 k ............ - 0.205 0.215 0.213 0.212 0.211 0.206 Mean 0-210 Zero time = -0-05 min. Table I1 summarises the results of similar experiments carried out in order t o determine the influence of the concentration of the formic acid on the rate of reaction.The value of the monomolecular velocity coefficient kobs. is the measure of the rate of the reaction, and the consfancy of the quotient kObs./cHCO,H is satisfactory proof that the rate is proportional to the concentration of formic acid. The reaction between bromine and formic acid is therefore of the second order. It remained to investigate the influence of the hydrogen and bromine ions on the rate of reaction. TABLE 11. CHCO~H ............ 0.1409 0.1409 0.2113 0.2818 0.4227 kob. ............... 0.092 0.096 0.146 0.102 0.284 ~ O ~ . / C H C C J ~ H ...... 0.653 0.681 0-693 0.683 0.673 Jakowkin (2. physihl. Chem. 1896,20,19) and others have shown, as a result of partition experiments that bromine in a solution containing excess of bromine ions is present largely as the tribromide ion.The equilibrium constant has been calculated to about 0-063 assuming complete dissociation of the electrolytes involved. The corresponding constant for the CHB~ = 0.1820 g.-mol. per litre. . . . . R = [Br’][Br,]/[Br,’] * (1 REACTION OF BROMIXE WITH AQUEOUS FORMIC ACID. 2717 combination of bromine molecules with chlorine ions is of the order of 0.8. Now in order to study the reaction at different concentrations of hydrogen ion it is necessary to add varying quantities of some strong acid and for this purpose hydrochloric acid appeared most suitable. But sufficient hydrobromic acid must be present not only to maintain the bromine-ion concentration constant but also to outweigh the much slighter influence of the chlorine ion in removing bromine molecules from the solution and so render the disturbing effect of the chlorine ion negligible.Table I11 summarises the results of experiments carried out on these lines. The normality of the hydrobromic acid was 0.1213 throughout and that of the hydrochloric acid never exceeded 0,2540 so that the disturbing effect of the chlorine ion would never be serious. Under " a " are given the activity coefficients of hydro-chloric acid (Lewis and Randall " Thermodynamics," 1923 p. 336) for the total acid concentration; for since coefficients for hydro-bromic acid were not available it was assumed that they would not be very different from those for hydrochloric acid. TABLE 111.CHCO~H = 0.282 g.-mol. per litre. Cmr = 0.1213N. CHCi ( N ) . C(HBr,HCI) ( N ) . a. kOb6. Q x c(HBr.HQ) x ICObr. 0.0oO 0.1213 0.807 0.353 0.0346 0-0252 0.1467 0-798 0.298 0.0349 0.0402 0.1637 0.793 0.269 0.0349 0.0807 0.2020 0.782 0.216 0.0341 0.1794 0.2907 0.769 0.157 0.035 1 0-2540 0.3753 0.763 0.125 0.0346 The constancy of the figures in the last column shows that the rate of reaction is inversely proportional to the active or effective concentration of the hydrogen ion. This is readily explained on the assumption that the ions of formic acid react and not the undissociated molecules. Formic acid is a comparatively weak acid obeying the dilution law so that in the presence of excess of hydrogen ion the concentration of formyl ion is inversely propor-tional to the concentration of the hydrogen ion.It was anticipated that the influence of the bromine ion on the rate of reaction might be accounted for by the removal of bromine molecules as tribromide ions provided that these do not take pad in the reaction. If the expression (eq. 1) for the equilibrium between free bromine molecules bromine ions and tribromide ions is combined with equation 2 which represents the total concen-tration of bromine in the solution (= {Br,}) in terms of the concen-tration of free bromine molecules (= [Br,]) and of tribromide ion 2718 -CK CHISO ON AND SNELL THE RATE OF a relation (eq. 3) is obtained between total bromine free bromine, and bromine-ion concentrations. . . Assuming now that the reaction is due to the free bromine molecules, it is found that the reaction velocity should be proportional to their concentration at any instant and that the monomolecular velocity coefficient should be related to the bromine-ion concentration by the equation k ~ b .= K2/(l + l/Kl[Br‘]) . . . . (4) Two methods are available for testing these conclusions. The h t of these the results of which are in Table IV consists in keeping the hydrogen-ion concentration constant by the introduction of a sufficient quantity of hydrobromic acid which also supplies the minimum excess of bromine ion necessary to give the mono-molecular velocity coefficient and then varying the bromine-ion concentration by the addition of potassium bromide. TABLE IV. C H C ~ H = 0.278 g.-mol. per litre. 0-OOO 0-1010 0.050 0-151 0.101 0.202 0-140 0.251 0-202 0.303 0.303 0.404 CgBr ( N ) .C(HBrtKBr)(N). The value of the constant R (eqs. 1 and 4) was obtained by plotting the reciprocal of the monomolecular velocity coefficient against the corresponding bromine-ion concentration and for this it was assumed that all the electrolytes were completely diisociated. A good straight line was obtained (compare eq. 4) and from the point where this cuts the Br’ axis the value of K can be deduced. The constancy of the numbers in the last column shows that for the value of 0.110 for K the figures agree well with the theory, although this is a value considerably higher than that (0.065) found by Jakowkin (loc. cit.). It was realised that a possible reason for the discrepancy may be the assumption made that the electrolytes are completely dis-sociated; whereas the activity of the bromine ion varies quite considerably over the range of concentration used.Accordingly, in the second method of studying the effect of the bromine ion a correction has been made for the activity. Here the concentration of the hydrobromic acid was vaned and the corresponding mono-molecular coefficients were determined. The simple relation tha REACTION OF B R O ~ E WITH AQUEOUS F O ~ C ACID. 2719 was shown to exist between the effective concentration of the hydrogen ion and the velocity of the reaction (Table III) was then employed to eliminate the influence of the changing hydrogen-ion concentration. Table V contains the results of the experiments carried out in order to test this method of attack.The second column gives the activity coefficients for hydrochloric acid (loc. cit.) which as before, were assumed to be not very different from those for hydrobromic acid. The pairs of values of kob. given in the fourth column are TABLE V. C H ~ H = 0.278 g.-mol. per Iitre. K = 0.070. 8 = b b a . Q x CHBr (1 + 1/Q x kOba.CHBr). CHBr ( N ) . a. a x e€tBr(N). kod. a x koba~mr. 0.0555 0.848 0.0471 ;::$} 1.014 0.0478 0.1110 0.820 0-091 1 ~ ~ ~ ~ ) 0.398 0-0362 0.1665 0.793 0.1320 ~ ~ ; ~ } O - Z I l 0.0280 0.2220 0-780 0.1730 :::%36)0-140 0.0242 0.2775 0.771 0.2140 :::;:} 0-094 0.0201 8 . 0*0800 0.0833 0-0808 0.0836 0.0816 the results of pairs of experiments under identical conditions. In the first of each pair the initial concentration of bromine was about 0.010 g.-mol.per litre whilst in the second it was about 0.005 g.-mol. per litre. The mean of each pair (fifth column) was used in the subsequent calculations. The activity of the hydrobromic acid is given in the third column. The product of this activity and the corresponding monomolecular velocity coefficient giva (sixth column) the corrected values of kOb. The reciprocals of these corrected values were plotted against the activities of the hydro-bromic acid or effective concentrations of the bromine ion and the value of 0.070 for Kl was deduced from the resulting straight line.* The constancy of the numbers in the seventh column shows that for this value of K the results of the experiments are in good agreement with the theory.It is necessary from the point of view of this treatment that the activity of the tribromide ion should be considered equal to its concentration. This assumption is justified by the fact that the concentration of the tribromide ion is always low. And further the two experiments of each pair agreed well * If the value of R is calculated from the results in Table V (as it was in the case of the results in Table IV) without introducing the activities of the ions the resulting figure is 0.105. This is in good agreement with the value 0-110 obtained from Table IV 2720 RATE OF REACTION OF BBOXINE WTTH AQUEOUS FORMIC ACID with each other in every case although the initial concentration of bromine and therefore of tribromide ion was halved in the second of the two.For the purpose of accurate comparison with Jakowkin’s results ( b c . cit.) it was necessary to recalculate using activity coefficients the value of K from his figures. He gives no results for cases where the concentration of bromine was less than 0.04 g.-mol. per litre and the value of the constant tends to increase with increasing dilution of the bromine. For this reason only those figures were considered which refer to the most dilute bromine solutions and to concentrations of potassium bromide of the same order as those of hydrobromic acid used in the present investigation. The activity coefficients for potassium bromide were taken as identical with those for potassium chloride (Lewis and Randall, op. cit.). The mean value of K, in terms of the effective concen-tration or activity of bromine ion was then calculated to be 0.048 as compared with 0.070 the value deduced from the results in Table V.It follows that like those in Table IVY the results in Table V agree in giving a figure for K considerably higher than that generally accepted for pure aqueous solutions. Summary and Discussion. The reaction between bromine and formic acid has been studied in dilute aqueous solution using the Ostwald isolation method. It is shown that formic acid is completely oxidised to carbon dioxide. The reaction is of the second order but the rate is retarded by the hydrobromic acid produced. From a study of the separate effects of the hydrogen and bromine ions it is deduced that the reaction takes place between the formyl ions and free bromine molecules i.e. those molecules of bromine which are not combined with bromine ions to give the complex ions Br3’. It is necessary to give to the constant for the equilibrium between bromine mole-cules bromine ions and tribromide ions a value considerably higher than that due to Jakowkin. Jakowkin’s experiments however, were performed with concentrations of bromine considerably higher than those used in the present investigation and his constants show it regular increase with increasing dilution of bromine. THE BALLIOL AND TRINITY LABORATORIES, OXFORD. [Received August 28th 1925.

ISSN:0368-1645    

DOI:10.1039/CT9252702715

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

LACTONIC ESTEaS DEB;IVED FROM PHENACYL BROMIDE Em. 2721 CCCLXXII.-Lactonic Esters derived from Phenucyl Bromide by Condensation with Ethyl Sodiomalonate and Analogc~us Substances. By RAMONI MOBAN RAY and J~ANENDRA NATH RAY. THE primary object of this work uix. the preparation of m-sub-stituted tetrahydronaphthalenes was not achieved. o-Benzoylbenzoic acid is readily convertible into anthraquinone. It was hoped therefore that phenacylmalonic ester under suitable conditions would pass into a tetrahydronaphthalene derivative. In presence of 6% aqueous potassium hydroxide however the reaction followed another course the lactone I (R=H) being formed, which gave benzoic acid on oxidation. OH 0 /\ PhE YO (1.1 Phl-g2:k2Et H HC--CR*CO,Et (R=H Me Et COMe CKPh or CHMe2.) Lactones of type I were also formed in the reactions between phenacyl bromide and the sodio-derivatives of malonic benzyl-malonic isopropylmalonic acetyhalonic and benzoylmalonic esters.Varying quantities of acetophenone also were produced, due to reduction of phenacyl bromide. Phenacyl bromide ethyl cyanoacetate and sodium ethoxide reacting in molecular quantities in alcoholic solution gave ethyl diphenacykyunoacetate (COPh*CH2),C(CN)*C0,Et but when dry ethyl sodiocyanoacetate (2 mols.) was heated for several hours with phenacyl bromide (1 mol.) suspended in dry benzene a sub-stance m. p. 125-127" was obtained which is believed to be the mono-substitution product. This could not be converted into a tetrahydronaphthalene derivative under a variety of conditions./ EXPERIMENTAL. The reactions of phenacyl bromide with the following substances were examined. With Ethyl Sodiomalonate.-The sodio-derivative (prepared from 0.7 g. of sodium and 5 C.C. of ethyl malonate) in cooled absolute alcohol (30 c.c.) was shaken vigorously with phenacyl bromide (6 g.). After 10 minutes the mixture now neutral was poured into much water ; by extraction with ether ethyl phenacylmalonate waa obtained as an oil (8 g.) d 1-2. The crude ester was shaken in the cold with 6% potassiu 2722 umomc ESTERS DERIVED FBOM PHENACYL BROMIDE ETC. hydroxide solution (65 c.c.). The red semi-solid mass that had separated after 12 hours was crystallised from rectified spirit the lactone (I ; R= H ) of a-carbethoxy- y-hydroxy- y-phenyl- A@-propene-carboxylic acid being obtained in colourless needles m.p. 105" (Found C 67.6. C13H1206 requires C 67.2%).* By keeping the lactone (1 g.) for 12 hours in a minimum of cold alcohol saturated with dry ammonia the corresponding umide, CloH,02*CO*NH, was obtained in long needles m. p. 153-154" after crystallisation from dilute alcohol (Found N 7-1. C,,%03N requires N 6.9%). "he lactone (1 g.) was oxidised with NjlO-sulphuric acid (50 c.c.) and N/10-potassium permanganate (excess) on the boiling-water bath. Ether extracted benzoic acid from the product after the usual treatment. With Ethyl Sodiocyunomtate.-An alcoholic solution of the reactants (1 mol. of each) was heated on the water-bath for 6 hour and then poured into water. The precipitate formed was removed after 12 hours; the filtrate gave nothing to ether.By fractionally crystaking the precipitate from 50% alcohol ethyl diphenucyl-cyunoacetate m. p. 141" (Found N 4.3. C,lHl,O,N requirea N 4.0%) was obtained together with a small quantity of a sub-stance m. p. 125-127". With Ethyl AcetylsodiTlomte.-Ethyl acetylmalonate was pre-pared by treating " molecular " sodium (1 atom.) with ethyl malonate in ice-cold dry ether and warming the mixture with acetyl chloride (1-25 mols.) a t 33" for an hour. The product after decom-position with a small quantity of water was shaken with ether. The dried extract was fractionated; the portion b. p. 125-128'117 mm. was pwe acetylmalonate (yield 60%). Ethyl acetylmalonate (4 c.c.) was added to alcoholic sodium ethoxide (0.46 g.of sodium in 25 c.c.); the mixture was treated with 4 g. of phenacyl bromide and after a few minutes warmed a t 50-55" for 4 hour. Ether extracted from the product diluted with water the lactone (I ; R=CO*CH3) of ethyl a-acetyl-y-hydroxy-y-phenyl- A@-propenecarboxylic acid which crystallised from alcohol and ether in needles m. p. 135-136" (Found C 65-6. C15H14O5 requires C 65.7%). As ethyl acetylmalonate is easily decomposed into ethyl aceto-acetate by alkali the compound m. p. 119-120" prepared from phenacyl bromide and ethyl sodioacetoacetate was compared with the preceding lactone; it depressed its m. p. With Ethyl Sodioethylmahte.-The reaction was carried out as * The humidity of the air (cu. 80%) d e determinations of hydrogen almost impossible !I!HE SYSTEM CH3.C0.0.CH3+H,0 O H 3 * 0 H + ~ C O * O H . 2723 in the case of ethyl sodiomalonate. The lactone produced (I ; R=Et) crystallised from alcohol in needles m. p. 134-135" (Found C 69.3. C1,H,,04 requires C 69.2%). With Ethyl SodiobenzyZmaEonate.-The Zuctone (I; R=CHJ?h) obtained crystallised from alcohol in flat needles m. p. 125" (Found : C 73.8; H 6.2. C&E€,,O requires C 74.5; H 5.6%). With Ethyl SodioisopropyZmal.-The constituenfs in mole-cular proportions were boiled in alcoholic solution on the water-bath for 1 hour. The product on dilution with water deposited the lactone (I; R=CHMe,) which crystallised from alcohol in needles m. p. 151" (Found C 69.7; H 6.5. C,,H,,O requhy C 70.1 ; H 6.5%). Our thanks are due to Sir P. C. Riiy for his interest in this work. COLLEGE OF SCIENCE CALCrma. [Received September 3rd 1925.

ISSN:0368-1645    

DOI:10.1039/CT9252702721

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

!I!HE SYSTEM CH3*COrnO*CH3+H,0 O H 3 * 0 H + ~ C O * O H . 2723 CCCLXXII1.-Equilibrium in the System : CH;CO0O*CH3 + H,O += CH;OH + CH;CO*OH. By GEORGE JOSEPH BURROWS. FROM the results of experiments on the rate of hydrolysis of methyl acetate by acids in the presence of various amounts of wafer and acetone it appeared that the equilibrium between the ester wafer, alcohol and acetic acid varied considerably. Jones and Lapworth (J. 1911 99 1427) have shown that the equilibrium constant of ethyl acetate varied between 6 and 9 for solutions containing hydro-chloric acid in which the ratio of molecules of water to hydrogen chloride varied from 6.2 to 4.6. In the case of methyl acefate, Berthelot and P6an de St. Gilles (Ann. Chim. Phys. 1863 68 225) found that if equivalent quantities of acetic acid and methyl alcohol were mixed 67.5% of each had combined at equilibrium, from which result K = 4-31.The value obtained from Mens-chutkin's results (Annden 1879 195 334) is K = 5.18 whilst Worley (Proc. Roy. Soc. 1912 A 87 582) deduced the value 6.6 by extrapolation for a solution containing no added catalyst. Results are now given for the value of K for solutions containing relatively low concentrations of water and the effect of diluting the system with various quantities of water methyl alcohol and acetone has been studied. The acetone was added with the intention of diluting the system with a substance not participating in the reaction. Special precautions were taken to dehydrate the alcohol eater and acetone. It has been found that the value of K is dependent no 2724 BUTCROWS EQUILIBRIUM IN THE SYSTEM : only on the ratio [H,O] [HCl] but also on the amount of methyl alcohol or acetone present in the solution.Only for solutions con-taining a large excess of methyl alcohol is K in the neighbourhood of 4 in all other cases it is considerably greater. For solutions containing approximately equal amounts of water and ester in which the ratio of molecules of water to hydrogen chloride is not greater than 7 to 1 K is greater than 12. As the amount of water relative to hydrogen chloride is increased the equilibrium constant decreases approaching 7 as the limiting value for a solution in which the ratio [H,O] [HCl] is about 1OOO. The value of K is also decreased by the addition of acetone to the solution the effect being smaller than that observed when the system is diluted with excess of water.A considerably greater effect is observed when the system contains a large excess of methyl alcohol. Thus for a solution in which the ratio [HCl] to [H,O] to [CH,*OH] was 1 to 7-8 to 2-2 R was 11.92, whereas the values 5-87 and 4-34 respectively were obtained for solutions in which the ratios were 1 to 9.6 to 32.6 and 1 to.625 to 2 639. This displacement of the equilibrium by hydrogen chloride indicates that the latter alters the activity of one or more of the reactants so that the total concentrations of water methyl acetate, acetic acid and methyl alcohol found at equilibrium in the usual way are in reality not the concentrations actually participating in the equilibrium.At present it is not possible to state what fraction of each of the substances is rendered inactive in this way but the results recorded here are capable of explanation by such a theory. It is now definitely established that in a solution of hydrogen chloride in water only a portion of the hydrogen chloride and water molecules are in an active condition. Thus from electromotive-force or vapour-pressure measurements of a series of such mixtures one can calculate the activity of water in the presence of different amounts of hydrogen chloride. The figures in the seventh column in Table I taken from the results of Dobson and Masson (J. 1924, 125 671) represent the fraction of the water molecules in each particular solution that are in the active condition.The figures in the eighth column are obtained by multiplying K by the ‘‘ water activity ” in each case and it will be seen that these numbers are constant and equal to about 7. This would indicate that the con-centration of water participating in the equilibrium is the same as the active concentration found from vapour-pressure measurements. Furthermore the constancy of this product points to the fact that, for the particular concentrations in this series the effect of the hydrogen chloride on the equilibrium constant is due almost entirel CH3*CO.O*CBj+H,O CH,*OH+CH3*CO*OH. 2725 to its effect on the activity of the water. There can be no doubt that the catalyst affects to some extent the activity of the other reactants but it would appear from these results that this effect is negligible in comparison with the effect on the water or else the individual effects on the ester alcohol and acetic acid neutralke one another or have a constant value in these cases.Figures are not available for the effect of hydrogen chloride on the activity of these three substances. McBain and Kam (J. 1919, 115,1332) have recorded results for the vapour pressures of mixtures of water and acetic acid a t the boiling point with and without the addition of neutral salts. These authors concluded from their results that “many salts enhance the partial vapour pressure of acetic acid in aqueous solution by very appreciable amounts. The undissociated acid must be regarded as exhibiting enhanced chemical potential in the presence of such salts.’y The increase in the partial pressure is proportional to the concentration.The results given in Tables VI and VII can be explained at least qualitatively on the assumption that the addition of hydrogen chloride to an aqueous solution of acetic acid has an effect on the activity of the molecules of the latter similar to that resulting from the addition of a neutral salt. The addition of a large excess of methyl alcohol to the system under discussion results in a marked decrease in the value of K . But an increase in the concentration of methyl alcohol relative to hydrogen chloride conesponds to a decrease in the concentration of acetic acid relative to hydrogen chloride, i e . to an increase in hydrogen chloride relative to acetic acid.The observed decrease in K with increasing alcohol concentration can thus be explained on the assumption that it results from an increase in the activity of the acetic acid under these conditions. At present it is not possible to treat the subject quantitatively but experiments are now in progress from which it is hoped to determine the actual effect of hydrogen chloride on each of the reactants in a system such as this. E x P E R I M E N T A L. Freshly distilled methyl acetate mixed with the desired quantity of water and hydrochloric acid was kept for 2 or 3 days in a stoppered flask until the mixture had become homogeneous. The weight of hydrogen chloride in a given weight of the acid used was previously determined. Small quantities of this stock solution were then mixed with various amounts of water acetone methyl alcohol or methyl acetate and sealed in hard glass tubes which had previously been steamed and dried.All quantities of the different liquids were weighed. The liquids used were p d e d and dehydrated by suitable means and their purity was ascertained by boiling poin 2726 BURROWS EQUILIBRXUM IN THE SYSTEM : and density determinations. The acetone and methyl alcohol were dehydrated with metallic calcium. The methyl acetate was freed from acid by means of sodium carbonate and dehydrated with calcium chloride. It was then distilled the middle portion of the distillate being used in these experiments. A sample treated in this way was hydrolysed with barium hydroxide solution and the amount of methyl acetate found was 99.7% of the theoretical.The tubes containing the Merent solutions were kept in a thermostat a t 25.0" for Merent intervals of time varying from 2 to 10 weeks according to the amount of hydrochloric acid present. The tubes were then opened under neutral sodium acetate solution, and the amount of acetic acid was determined by titration with barium hydroxide solution. Blank experiments were performed which showed that the solutions had no determinable.effect on the glass tubes. The figures given in the following tables represent the number of gram-molecules of the merent substances present a t equilibrium. The values of the equilibrium constant were calculated from the equation K = [AcOMe][H,O]/[AcOH]~eOH]. The effect of hydrogen chloride on the equilibrium constant is shown by the results in Table I.For the first four experiments in which the amount of water was comparatively small K is much larger than is the case for the solutions for which the ratio [H,O] [HCI] was high. As stated above the products of these high values of K and the '' water activity " are approximately constant. TABLE I. [HClI x 103. 5-57 4.245 4.49 4-59 4.53 5-01 0.446 0.444 0.0576 [AcOMe] 84.86 44.57 34-10 34.00 24.8 1 2-76 32-44 25-14 19-65 x 103. LH#I x 103. 31-14 31.84 34-74 35-96 135.7 261-6 36-8 113-6 27.80 [AcOH] = [MeOH] x 103. 14.36 10.80 10.13 19-65 12.33 19-40 9.935 9.565 8-667 [H*Ol. [HCll 6.82 7-50 7-74 7-83 30.0 52.2 82.5 255.9 482-7 Water activity, K .a. K a. 12-82 0-525 6-8 12-17 0-56 6-8 12.01 0.57 6.8 11.92 0.58 6.9 7.59 7-27 * Accurate figures for the value of the " water activity " in dilute solutions are not available but by interpolation from the other values the activity in these five cases is found to vary from about 0.9 to 1. The product K x " water activity " for these dilute solutions is therefore approximately 7. In the next series of experiments the effect of diluting the system with acetone was studied. The results are in Tables 11 111, and IV 2727 [Hal x 103. 4-49 4-53 4-48 4.48 4.49 1-34 [AcOMe] 34.10 34.34 33-78 33.64 33.61 9-85 x 103. TABLE g . [H,O] [AcOH] =[MeOH] [Me,CO] x 103. x 103. x 103.K. 34.74 9-936 - 12.01 35-00 10.17 8.00 11-63 34.44 10.14 21.1 11.32 34.30 10-31 63.7 10.85 34-27 10.43 79.7 10.60 10.05 3.147 106.0 9-99 The ratio [H,O] [HCl] is nearly constant throughout the above series and is equal to 7.7. TABLE m. [Ha] [AcOMe] [H,O] [AcOH]=[MeOH] [Me,CO] x 103. x 103. x 103. x 103. x 103. K . 4.59 34-00 35.96 10.13 - 11-92 4.59 33-86 35.83 10.32 14.3 11.4 4-54 33-25 35-15 10-43 30-0 10.75 4.49 32-81 34.74 10.38 53.4 10.58 Although the results in these two tables are very similar they represent two distinct sets of experiments the solutions being prepared from entirely different samples. TABLE IV. [Hal x 103. 0-446 0.444 0-391 0446 0.446 0.444 0.445 [AcOMe] x 103. 32.44 32-21 28.28 32-12 32.02 31-82 31.82 [HsO] [AcOH] =[MeOH] [Me,CO] x 109.x 103. x 103. 36-80 12-33 -36-57 12.33 8-26 32.12 10.91 2.52 36-47 12.64 16-0 3640 12.75 29.2 36-15 12.79 38-8 36- 19 12-83 47.2 K. 7.85 7.75 7-63 7.33 7-17 7.04 7-00 The ratio [H,O] [HCl] in this case is 81. The results in these three tables show that the presence'of acetone decreases the value of the equilibrium constant but when the ratio [H,O] [HCl] is low the effect is less than that caused by the addition of the same number of molecules of water to the system (Tables I1 and III) whereas it is apparently greater in the case of a solution in which there is a great excess of water over hydrogen chloride (Table IV). In the former case a solution containing 7.7 molecules of water and 79 of acetone to 1 of hydrogen chloride gives a value for R equal to 10 whereas a solution containing 86 molecules of water to 1 molecule of the acid would have a value of 7.8.In the latter case however the value for a solution containing 80 molecules of water and 106 of acetone to 1 of hydrogen chloride is less than that for a solution containing 186 molecules of water 2728 THE SYSTEM CH~.CO.O.CH~+H~O e CH~.OH+CH~.CO.OH. The effect of increasing the concentration of methyl acetate is shown by the results in Table V ; K increases slightly with increasing concentration of ester. TABLE V. WCI] [AcOMe] [H,:] [AcOH]=[MeOH] x 103. x 103. x 10. x 103. I<. 4.69 34-00 35-96 10.13 11-92 4-25 44-57 31.84 10.80 12-17 4-64 64.61 33.42 13-22 12-36 4-68 79-88 31-61 14.08 12.74 The effect of adding methyl alcohol to the system is shown by the results in Tables VI and VII.TABLE VI. [HCI] [AcOMe] [H,O] [MeOH] [AcOH] x 103. x 103. x 103. x lo8. x 103. (MeOH]:[HCI]. K . 4.59 34.00 35-96 10.13 19.13 2.2 11.92 4.57 38-45 40-37 33.57 5.51 7-3 8-39 4-59 40-34 42-30 63-16 3.794 13.8 7-12 4.60 42-13 44-08 149.4 2.118 32.6 5-87 In this series the ratio [H20] [HCl] increases from 7.7 to 9.6. TABLE VII. [HCI] [AcOMe] [H,O] [MeOH] [AcOH] x 103. x 103. x 103. x lo3. x lo3. [MeOH] [HCI]. K. 0-0576 19.65 27.80 8.667 8.667 150-5 7-27 0-0576 26.03 34-22 79-20 2.418 1375 4.65 0.0576 27-63 36.02 152.0 1-51 2639 4.34 In this series the ratio [H20] [HCl] increases from 483 to 625. The usually accepted value for the equilibrium constant was found only in the last two experiments of this particular series. It is concluded from the results given in the last column of Table I, that the true equilibrium constant corrected for the effect of hydrogen chloride is 7 and that the low results given in Table VII are due to the effect of the hydrogen chloride on the acetic acid just as the high values of K in Table I are attributable to its effect on the activity of the water. The author is indebted to the McCaughey Research Fund Com-mittee for a grant to defray the expense of this investigation. THE UNIVERSITY SYDNEY. [Received September 16th 1925.

ISSN:0368-1645    

DOI:10.1039/CT9252702723

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

SYNTHESIS OF 2 3 5 (OR 2 3 NAL TRIM ETHYL GLUCOSE. 2729 CCCLXX1V.-Synthesis of 2 3 5 (or 2 3 4)-Tri-methyl Glume.* By JAMES COLQUHOTJN IRVXNE and JOHN WALTER HYDE RECENT developments in the constitutional study of carbohydrates demand that from time to time the structure of the simple methyl-ated sugars utilised as reference compounds in such work should be brought under review. In the present case we have selected 2 3 5-trimethyl glucose for further examination as this sugar is the key to the const.itution of both maltose and p-glucosan and acquires further importance in comexion with the chemistry of starches. Obviously the sigmficant feature of this particular form of trimethyl glucose is the non-reducing hydroxyl group as the identification of its position indicates the linkage of the two glucose residues in maltose and also the attachment of the anhydro-ring in p-glucosan.In order to give a clear view of the present position, it may be recalled that 2 3 5-trimethyl glucose was first obtained, in the form of the corresponding methylglucoside (Purdie and Irvine J. 1903 83 1021; Purdie and Bridgett ibid. 1037) by methylating methylglucoside in the presence of excess of methyl alcohol. The free sugar was also studied by the above workers, who converted it into 2 3 5 6-tetramethyl glucose and tentatively ascribed to it the structure still in use. Their views were after-wards supported by Irvine and Dick (J. 1919 115 593) who showed that on oxidation by nitric acid the sugar is converted into a trimethyl saccharo-lactone.This observation was con firmed by Haworth and h i t c h (ibid. 809) who isolated the m e sugar from fully methylated maltose and by Irvine and Oldham (J. 1921 119 1744) in studying the structure of p-glucosan. Although there seemed no reasonable doubt that the methylated glucose in question was correctly formulated the evidence obtained by subjecting sugars to the oxidising action of nitric acid should not be accepted as final so long as other and more diagnostic tests are available. The divergent results obtained by Irvine and Hogg (J. 1914 105 1386) and by Levene and Meyer ( J . Bio2. Chem., 1922 54 805) in oxidising monomethyl glucose by means of nitric acid may be quoted in illustration of this point. The constitution of 2 3 5-trimethyl glucose has now been In a letter to Nature 19th September 1925 Haworth states that he has obtained evidence leading to the conclusion that normally the oxidic ring in glucose couples positions 1 and 5.Should this be substantiated the methyIated glucose which f o m the subject of the present communication should be indexed as 2 * 3 4-trimethyl glucose. OLDHAM 2730 IsVINE AND OLD-: confirmed by the following synthetical scheme which was designed to produce a methylated glucose with 'unsubstituted hydroxyl groups definitely in the terminal positions 1 and 6. Triacetyl glucosan was converted by Karrer's process into triacetyl dibromoghcose identical with that previously obtained by Fischer from penta-acetyl glucose. Stage 11. The above dibromo-derivative when treated with methyl alcohol in the presence of silver carbonate gave triacetyl methylglucoside bromohydrin and the subsequent reactions were therefore designed to replace acetyl by methoxyl and thereafter to introduce the hydroxyl group in place of bromine.The acetyl groups were removed by the action of alcoholic ammonia giving methylglucoside bromohydrin. It may be mentioned that although the physical constants mere other-wise in good agreement the melting point of this compound was found to be several degrees higher than that quoted by Fischer. Methylation of methylglucoside bromohydrin under conditions which would have the minimum effect on the bromine atom was achieved by the silver oxide reaction and gave a mixture of (a) trimethyl methylglucoside bromohydrin (800/) and (t) the corresponding enolic anhydride (20%).From this mixture pure trimethyl methylglucoside bromohydrin mas isolated. Stage V . The above compound when heated at 150" with alcoholic potassium acetate gave a 72% yield of pure crystalline trimethyl p-methylglucoside identical with that obtainable from the form of trimethyl glucose which is the subject of the investig-ation. In the glucoside h a l l s obtained the hydroxyl group occupies the position of the bromine atom in triacetyl methylglucoside bromohydrin. As Fischer succeeded in reducing the latter to triacetyl methylisorhamnoside (Ber. 1912 45 3761) the group is therefore in the 6-position. In consequence the methyl groups in the corresponding sugar must be in positions 2 3 and 5.Although we are unwilling to attach undue importance to colour tests the proof is strengthened by the following considerations. In the glucose molecule positions 1 2 3 and 5 are occupied by secondary alcohol groups and the only primary alcohol group is in the 6-position. If therefore the vacant hydroxyl group in a trirnethyl methylglucoside is primary the corresponding nitro-derivative should give a red colour by Meyer's test; otherwise tt blue solution will result. Trimethyl methylglucoside bromohydrin was therefore converted into t'he corresponding iodohydrin which was transformed with some diEculty into mononitro-trimethyl methylglucoside. This on treatment with nitrous acid gave as Stage I . Xtage I I I . Stage I V. This result supplies the evidence required SYNTHESIS OF 2 3 5 (OR 2 3 ~)-TRR~ETHYL GLUCOSE.2731 expected the characteristic red colour similar to that obtained from nitromethane. In verification of our former work on p-glucosan we have repeated the conversion of this anhydroglucose into trimethyl glucose and subjected the sugar to the following successive operations : I. Acetylation giving trimethyl glucose diacetate. 11. Bromination by the action of hydrogen bromide in glacial acetic acid giving trimethyl acetyl glucose bromohydrin. 111- Action of sodium methoxide giving trimethyl P-methyl-glucoside. The methylated glucoside finally isolated was identical with that obtained in the synthetical processes already synopsised thus confirming that P-glucosan is 1 6-anhydroglucose.In order to render the scheme of reactions intelligible the various changes involved in the two alternative methods of producing 2 3 5-tri-methyl methylglucoside may be represented structurally : I. From Penta-acetyl Glucose or from Triacetyl G1ucosa.n. rFHBr ryH*OMe b cjH*OAc YH-OAc 1 yH*OAc CH-OAc 'H*OAc r$!H*OMe rFH=OMe CH-OMe I YH-OMe A tH*OMe YE*oue LCH LYH hH*OMe YH-OMe Penta -ace tyl glucose or + I YH*OAc ~ g1ucosa.n T riacet yl LYH LYH Stage 1. hH2Br Stage 11. &H2Br Stage IV. bH,Br Stage V- CH,*OH 11. From Glucosan. p-1 rYH-1 l$JH*OH I &vH*OMe 1 [vE:Ege I YH'OH I CH*OMe I VH*OMe CH*OH 1 +H*OMe I $H*OMe dH2 -l CH,- CH,*OH ryHBr YH-OMe 4 YH-OMe LYH 0 --f L(!H 0 L(lH LPH -+ H*OMe YH-OMe CH*OMe XH2*OAc C1H,-OAc h2*O 2732 IRVINE AND OLDHAM: The collective results may be compressed into the statement that dibromotriacetyl glucose maltose and glucosan are all convertible into the same form of trimethyl glucose.We are engaged in attempts to s-vnthesise other partly methyl-ated sugars and the isomeric distinction between 2 3 5- and 2 3 6-trimethyl glucose having now been established the results will be utiLised in forthcoming papers from this laboratory. E X P E R I M E N T A L . The following account of experimental procedure is limited to the synthetical reactions described in the introduction. Other reactions to which reference is made were carried out by methods which are now standardised and their description is therefore omitted. T r i m t y l Dibromogluwse from Triacetyl p-G1ucosan.-The method recommended by Karrer (Helv.Chim. Acta 1922 5 124) was adopted minor variations being introduced as the reaction which is most successful when small quantities of material are manipul-ated requires careful control. Triacetyl p-glucouan (in lots of 5 g.) was heated on a boiling water-bath with phosphorus pentabromide (8.5 g.) the flask being fitted with a ground-in condenser. When effervescence had nearly ceased the contents were poured into finely-crushed ice and thoroughly disintegrated by a glass rod. Similarly the residue in the flask was mixed as rapidly as possible with small pieces of ice until all halides of phosphorus had been destroyed. Rise of temperature must be avoided in these operations. The fine white powder resulting from several experiments was united washed with water until free from phosphoric acid and thereafter with absolute alcohol until the washings were nearly colourless.Purification was effected by dissolving in a small quantity of chloroform and precipitating with light petroleum. The yield of crystalline product (m. p. 173") including the material obtained from the mother-liquors averaged 50% of the theoretical amount. As the rotation of the compound does not appear in the literature the following values were determined : Solvent. C. ra3,. Chloroform ....................................... 1-537 + 189-9O Glacial acetic acid .............................. 1.256 + 185.9 Conversion of Triacetyl Dibrmoglucose into Triacetyl Methgl-gluwside Bromohydrin.-This reaction was carried out exactly as described by Fischer (Ber.1902 35 857; 1920 53 873) the yield of glucoside being nearly quantitative ; after recrystallisation from absolute alcohol the product melted a t 126-127". As i SYNTHESIS OF 2 3 15 (OR 2 3 4)-TRIMETHYL GLUCOSE. 2733 this case also no optical data appear to have been published the specific rotation in the following solvents was determined : Solvent. C. [a],. Chloroform ....................................... 3.012 - 1.4" Methyl alcohol ................................. 3.014 -3.1 Glacial acetic acid .............................. 3.006 - 2.7 Methylglumside Bromohydrin.-The acetylated methylglucoside bromohydrin obtained as above was dissolved a t room temperature in methyl alcohol containing 5-lOyo of ammonia so as to form a 5% solution.It is unnecessary to saturate the liquid with ammonia as stated by Fischer and the use of a dilute solution enables the end-point of the reaction to be determined polari-metrically. When the specific rotation had diminished to - 19-3", the product was isolated by evaporating to dryness and extracting with chloroform to remove acetamide. The yield of crude bromo-hydrin was nearly quantitative and after recrystallisation from ethyl acetate the compound melted and decomposed a t 153-154" in place of 148" as quoted by Fischer. In aqueous solution under conditions identical with those used by Fischer the specific rotation wits - 33~6"~ the literature value being - 34.9". Tribenzoyl methyQ1ucoside bromohydm'n has no dirdct bearing on the main investigation but reference may be made to it.The normal procedure was followed the bromohydrin being acted on by a slight excess of benzoyl chloride dissolved in pyridine. The product was brought into solution in a minimum of glacial acetic acid and the pure tribenzoate precipitated by addition of absolute alcohol m. p. 160-162"; [a], in chloroform - 5.0" for c = 2.413; needles insoluble in water and light petroleum and readily soluble in organic solvents with the exception of alcohol and ether. Trimethyl Afeth ylglucoside Bromohydm'n.-For the particular object in view alkylation by silver oxide and methyl iodide is the only method applicable to methylglucoside bromohydrin. The usual procedure was followed methyl alcohol being added during the first methylation.After four successive treatments the refrac-tive index was constant and the liquid product wits distilled a mobile syrup being obtained (b. p. 140°/l mm. ; nD 1.4720; [.ID in methyl alcohol - 20.5" for c = 1). Examination showed that at least two compounds were present one of them containing no bromine. This constituent was present to the extent of 20% and was evidently dimethyl anhydromethylglucoside (Found : C 42.7 ; H 6-7 ; OMe 41.7 ; Br 21.3. Calc. for trimethyl methyl-glucoside bromohydrin C 40.1 ; H 6.35 ; OMe 41.4; Br 26.7%. Calc. for a mixture of 80% of the above with 20% of trimethyl anhydromethylglucoside C 42-7 ; H 6.6 ; OMe 42.2 ; Br 21.3%) 2734 SYNTHESIS OF 2 3 5 (OR 2 3 ~ ) - ~ I M E T H Y L GLUCOSE.The close agreement with the experimental figures particularly the resulf of bromine determinations confirms the composition ascribed to the mixture. The constituents were separated by solution in ether and repeated extraction with water a process which completely removed dimethyl anhydromethylglucoside. After evaporation of the ether the residual syrup was fractionated in a high vacuum giving a liquid distillate which slowly crystallised. Owing to the ready solubility of the compound in all solvents with the exception of water no suitable recrystallising medium could be found but after spreading on a tile the crystals were hard and crisp m. p. 24" ; nD 1-4735 ; [.ID in acetone - 5.8" (c = 3.851), in methyl alcohol - 4.7' in benzene - 7-7' in chloroform - 3.5' (Found C 40-3; H 6-3; OMe 41-3; Br 27.2.Trimethyl methylglucoside bromohydrin requires C 40-1 ; H 6-35 ; OMe, 41.4; Br 26.7%). Hydroxylation of Trimethyl Methylglucoside Bromohydrin.-Re-liminary experiments having shown that both aqueous and alcoholic sodium hydroxide react with the bromohydrin eliminating hydrogen bromide and giving unsaturated derivatives the hydrosylation was effected by means of potassium acetate. A 3% solution of the bromohydrin in methyl alcohol was heated with excess of potassium acetate at 150" for 3 days during which the laworohtion increased greatly. The crude product on isolation in the usual manner was obtained in nearly quantitative amount but was contaminated with an unsaturated impurity. On keeping how-ever the syrup solidified and after draining on a tile and recrystallis-ing from light petroleum a 72% yield of pure trimethyl p-methyl-glucoside was obtained in characteristic crystals.The melting point was 93-94' a value which was unaffected when the material was mixed with an authentic specimen of the compound. The specific rotation also was in close agreement ([aID in chloroform - 11.9" for c = 1.084). It was ascertained that owing to the alkalinity of potassium acetate the above hydroxylation was accompanied by a side-reaction giving rise to an unsaturated compound; this is being further examined. Trimethyl Methylglumside 1odohydrin.-The general method described by Finkelstein (Ber. 1910 43 1528) was employed a solution of trimethyl methylglucoside bromohydrin in acetone being heated a t 100" for 6 hours with twice the theoretical amount of sodium iodide.After removal of the acetone the residue was extracted several times with ether and the united extracts were washed with aqueous sodium thiosulphate solution allowed to stand over sodium sulphate and evaporated to dryness. The product crystallised readily in needles and when drained on a tile G~LCHRJST AND PVRVES GLYCE~OL GLUCOSIDE. 2735 melted at 31-34'. Owing to the excessive solubility in all solvents except water no recrystallising medium could be found but the compound was evidently pure (Found OMe 36-1 ; I 36.5. Calc., OMe 35.8 ; I 36-77/ ; n 1-4992 ; [a], + 8.6" in chloroform for c = 3.637 + 4.1" in acetone for c = 34397 and + 6.5" in methyl alcohol for c = 4.221).Trimethyl methylglucoside iodohydrin wtts converted into the corresponding nitro-compound by heating with dry silver nitrite at 100" for 2 days. After distillation under diminished pressure the nitro-derivative was isolated in the form of the sodium salt by the addition of the calculated amount of sodium methoxide dissolved in methyl alcohol. On removal of the solvent the salt was dissolved in dilute sulphuric acid and the solution extracted with ether. After being washed with sodium thiosulphate solution to remove a trace of iodine the ethereal layer was dried and evapor-ated and the mononitro-trimethylglucoside isolated by distillation as a colourless syrup (nD 14603). Beyond checking the methoxyl content (Found OMe 464. Calc. OMe 46-7%) the compound wm not fully analysed as it was prepared solely for the purpose of carrying out the colour test with sodium nitrite and dilute sulphuric acid. This treatment gave a bright red solution free from any shade of blue and whilst the colour was not so intense or so lasting as that obtained under parallel conditions with nitro-methane the result was characteristically positive. The thanks of the authors are due to the Carnegie Trust for a Fellowship which has enabled one of them to take part in the work. UNITED ~OLLECIE OF ST. SALVATOB AND ST. LEONARD, UNIVERSITY OF ST. ANDREWS. [Received October 7th 1925.

ISSN:0368-1645    

DOI:10.1039/CT9252702729

出版商:RSC    

年代:1925

数据来源: RSC

摘要:

G~LCHRJST AND PVRVES GLYCE~OL GLUCOSIDE. 2735 CCCLXXV.-Glycerol Glumaide. By HELEN SIMPSON GILCHXIST and CLIFFORD BURROTJGH PURVES. FEW condensation reactions between reducing sugars and poly-hydric compounds of simple type have been studied possibly owing to the difKculty of producing such compounds and of purifying them when formed. As in the case of glucose and glycerol con-densation leads to a type of compound which may be regarded as analogous to a carbohydrate fat and is of physiological interest, we have taken up the investigation of this subject. Glycerol glucoside which was originally described by Fischer (Ber. 1894 27 2483) has now been obtained on the large scal 2736 GILCHRIST AND PURVES GLYCEROL GLUCOSIDE. by an improved process. The older method involving &s it does the saturation of a glycerol solution of glucose with hydrogen chloride is tedious but the same compound is more readily obtained by limiting the acid concentration to 0.25% and heating a t 100".The product in each case is a syrup possessing the properties of a glucoside but no information bearing on the composition or struc-ture of the compound has hitherto been available and it was unknown to which type the glucose residue belongs or to which part of the glycerol molecule it is attached. These questions have been solved by methylation which yielded hexametAyZ glycerol glucoside as a colourless volatile liquid b. p. 190-192"/12 mm. Hydrolysis thereafter yielded 2 3 5 6-tetramethyl glucose FIG. 1. 3 Gram8 of glucose dis8olved in 80 C.C.of ylycsrol. 3 6 9 12 15 18 21 Time in h~ur8. together with a dimethyl glycerol which was shown to be ap-di-methoxy-y- hydroxypropane. From these results the constitution of the parent glucoside is established to be : CH,( OH)*CH( OH )*CH=CH(OH)*CH( OH)*CH*O*CH,*CH( OH)*CH,*OH. The compound as prepared is a mixture of a- and p-forms and the optical values determined on hydrolysing the methylated derivatives show that glycerol y-glucosides were present only in small amount the limits in different preparations being 1-95 and 0.93%. The research was accordingly extended by varying the conditions of condensation the changes in rotation which take place when glucose is dissolved in glycerol containing hydrogen chloride being utilised to study the reaction.The concentration of -0 GILCHRIST AND PERVES GLYCEROL GLUCOSIDE. 2737 the sugar in no case exceeded 6% by weight of the glycerol employed and solutions containing more than 3% by weight of the acid were not examined. These limitations were found to be necessary as, when exceeded the high viscosity or the depth of colour resulting made polarimetric observations uncertain. For the same reason the experiments were carried out a t room temperature. In Fig. 1 the rotations observed for the condensation of glucose with glycerol are plotted against time. An unexpected feature, which comes to light is that the minjmum rotation does not appear F I ~ . 2. Solutions contain 80 C.C. of glycerol and 1.5 g r a m of hydrogen chloride. +13-3' 0 i - - s 8 8 -26.7' i3 -5234 to depend on the amount of hydrogen chIoride present.The reaction prociuct in each case was the glycerol glucoside described above as shown by the identical behaviour on methylation and subsequent hydrolysis. It was also found that on long standing the optical activity of an acid solution of glucose in glycerol reverts approximately to its original value apparently owing to the con-densation being reversed as a result of secondary reactions between the solvent and the acid. The slow speed of the condensation led to the investigation being extended to cases where glucose and fructose were dissolved in acid glycerol with the view of ascertaining if under these conditions the two sugars combined in whole or in VOL. CXXVII. 4 2738 GILCHRIST AND PriRVES GLYCEROL GLUCOSIDE.pad. In this connexion it was necessary to perform a series of control experiments with solutions in glycerol of fructose alone. In A (Fig. 2) the specific rotation of fructose dissolved in glycerol containing 1.5% of anhydrous hydrogen chloride is plotten against time; the behaviour of glucose under the same conditions is shown in B (Fig. l) while in C the ordinates are the algebraic mean of the corresponding ordinates in A and B. The latter curve predicts the behaviour of solutions containing both glucose and fructose, assuming that the sugars do not react with each other and the actual experimental observations are summarised in D. The values obtained tend to be more lsvorotatory than the calculated values and this was general for all concentrations of the acid reagent employed.Eventually it was found that this discrepancy was due -to the varying quantities of water formed by the condensation of the sugars with the solvent and to the effect this produced in the optical activity of fructose solutions. E records the observations made on a solution of fructose in glycerol which had not been rendered anhydrous whilst in the experiment represented by F the amount of water has been reduced by restricting the total concentration of sugars present in the solution to 3%. The close agreement of F with C indicates that under the experimental conditions outlined the behaviour of glucose is not affected by the presence of fructose. This conclusion was supported by the results obtained from an estimation of the reducing power of the above systems.For concentrations of the sugars up to 374 by weight the percentage loss in reducing power was found to be independent of the concentration. It therefore follows that in a solution containing both sugars condensation of one sugar with the other will cause the total reducing power of the mixture to be less than the sum of the reducing powers of the individual sugars. Xo such diminution was recorded although the degree of accuracy was such that condensation even to the extent of 5% would have been readily detected. Taking the combined results into con-sideration it is unlikely that glucose or fructose can combine in hydroxylic solvents or that reactions involving the condensation of glucose and glycerol play a part in natural processes.As already indicated it has proved necessary for the purposes of the resea;rch to ascertain which isomeric form of dimethyl glycerol is produced when hexamethyl glycerol glucoside is hydrolysed and it became evident that the complete series of methylated glycerols &odd be standardbed in view of future work in natural glycerides. The processes developed in this laboratory for determining the constitution of carbohydrates are equally applicable to the struc-problems of the natural fats including the mixed glycerides QILCHRIST AND PURVES GLYCEaoL GLUC0SI.DE. 2739 Methyhtion of partly hydrolyd fats followed by hydrolysis should give pa,rtly methylatel glycerols the constitution of which would lead directly to that of the parent compound.As a-methyl glycerol has already been fully described (J. 1915,107,337) this compound has not been re-examined but we have prepamid ap-dimethyl glycerol by the action of d u m methoxide on ally1 alcohol dibromide and determined the constaats of the pure liquid. In order further to characterise the compound it has been used as a solvent in which the specific rotation of active solutes wits determined. As an additional method of identifying the ether if was converted into y-benzoyl-ap-dimethyl glycerol and ap-dimethyl glycerol malate of which the constants were determined. Attempts to prepare ay-dimethyl glycerol led to a confusing result. Accordmg to Smith (2. physikd. Chem. 1918 92 717) the prod;ct of the action of hydrochloric acid on epichlorohydrin contains nothing but the pure ay-compound.The ay-dichlorohydrin prepared by this method gave however on treatment with sodium methoxide, a dimethyl glycerol which in all respects was identical with the ap-dimethyl glycerol described above. The identity was apparent’, not only in the ethers but also in the benzoates and malates pre-pared from them. Advantage was taken of the fact referred to above that liquid isomerides may frequently be distinguished by the effect they produce on the rotation of active compounds dis-solved in them. In this respect also no distinction could be made between the compounds. Cornparison of Dimethyl Glycerols. n of [a]? of B. p. n,. benzoate. mslate. afl-Dimethyl glycerol . .. 69-5-70-5”/15 mm. 1.4219 1-5075 - 10.48” Presumed ay-dimethyl glycerol ...............70.5-71-5”/18 mm. 1-4219 1.5075 - 10.60 Solvent. Solute. IaIIl. ab-Dimethyl glycerol Ethyl tartrate + 11-22O ay- 9 9 s 9 9 Y ? + 11.19 4- 9 9 ?7 Nicotine - 152.94 ay- 29 1 s $7 - 153.44 Comparison of the above data leaves no doubt that the com-pounds are identical and not isomeric. It has not yet been ascer-tained whether in this instance the action of sodium methoxide causes migration of the methyl groups but the following result suggests that Smith’s ay-dichlorohydrin is interchangeable with the a@-isomeride. It was expected that p-monomethyl glycerol could be obtained from ay-dichlorohydrin which when subjected t o methylation by the silver oxide reaction yielded a monomethyl dichlorohydrin. In such it compound the halogen atoms would 4 Y 2740 GILCHRIST AND PURVES GLYCEROL GLUCOSIDE.presumably occupy the ay-positions but on heating with an aqueous alcoholic solution of potassium acetate followed by hydrolysis of the acetyl groups the a-monomethyl glycerol described by W e and Macdonald (Zoc. cit.) was obtained. The result is comparable with that recorded by Fischer (Ber. 1920 53 1625) who starting from y-iodo-ap-distearyl glycerol replaced halogen successively by acetyl and hydroxyl and obtained not ap-distearyl glycerol, but the ay-isomeride. Trimethyl glycerol was prepared by the cont-hued action of methyl sulphate in alkaline solution on glycerol at 70". The product formed a constant-boiling mixture with water which distilled a t 92" whilst the distillate formed a homogeneous system with ether.The pure compound was a mobile liquid b. p. 148'1 765.4 mm. n = 1.4069. Ethyl tartrate dissolved in trimethyl glycerol gave [a] = + 5-99'. E X P E R I M E s T A L. Prepamtion of Glycerol G1ucoside.-A 5% solution of 20 g. of glucose in anhydrous glycerol containing 0.25% of dry hydrogen chloride was heated in a sealed tube at 100" until it no longer reduced Fehling's solution. The product isolated on the lines described by Fischer (loc. cit.) was a thick syrup containing barium chloride and glycerol. The glucoside was extracted with absolute alcohol and purified by precipitation with ether but this effected only partial separation of the impurities and the composition was determined through the methylated derivative.Methykction of Glycerol G1ucoside.-Only one typical experiment need be described. The syrup (16 g.) was methylated by the gradual addition of 72 g. of methyl sulphate and 55 g. of sodium hydroxide in 40% solution. The unchanged glycerol was thus converted into trimethyl glycerol which volatilised during the final heating to 100". The product (11 g.) was remethylated twice by means of the silver oxide reaction; the refractive index was then constant and on distillation a clear colourless mobile liquid was obtained b. p. 190-192"/12 mm. n = 14497 (Found C, 53-1 ; H 8.9. Hexamethyl glycerol glucoside CI5H3O8 requires C,%53.25; H 8.9%). With this compound as with many other derivatives of glycerol analysis by the ordinary combustion process gave variable results.The r' wet " process of Simonis and Thies (Chem. Ztg. 1912,97 917) gave however satisfactory values for carbon. Hydrolysis of Hexamethyl Glycerol GZuco.side.-A 7 ?$ solution of the glucoside in 8% aqueous hydrochloric acid was hydrolysed by heating a t 100" for 45 minutes the course of the reaction bein GILCHRIST AND PWVES GLYCEROL GLUCOSIDE. 2741 followed polarimetrically. After neutralisation with barium c a r h a t e the product waa extracted with chloroform and on distillation of the solvent crystalline tetramethyl glucose was obtained (yield 65%). After one recrystallisation from light petroleum the melting point mas 88" and a mixed melting point with tetramethyl glucose showed no depression. Evaporation of the light petroleum mother-liquors gave a solid the optical values of which were determined.In one preparation [a]D = + 75-65'. These results show that the corresponding glycerol y-glucosides may be present to an extent varying between 0.93 and 1095%. In order to isolate the methylafed. glycerol formed during hydrolysis, the aqueous layer was concentrated by distillation through an efficient column. The concentrated solution was extracted with ether and on evaporation of the solvent gave a/3-dimethyl glycerol as a colourless mobile liquid showing the correct physical constants for this compound. Pohrimetric Examination of the Condensartion of Glucose tdth Glycerol.-The glycerol used was redistilled under diminished pressure and the k e l y powdered glucose kept for some days in an evacuated desiccator over sulphuric acid.The sugar (3 g.) was dissolved in glycerol by heating at 90" for 2 hours the solution when cold showing a specific rotation of 52.3" and a reducing power equivalent to the glucose it contained. Dry hydrogen chloride was drawn into the solution until the necessary increase of weight was obtained (8-10 minutes) and a further 15-20 minutes elapsed before the turbidity of the liquid had decreased sufficiently to make possible even a rough determination of its optical rotation. The following typical results are recorded the complete figures being embodied in the curves shown in the introduction. Observed rotations 2 = 1 t = 15". Cone. of gIucose 3%. HC1 1%. HCI 1.576. Hcl 1-63?;. HCI 2:/0. HCI 2.53%. HCI 3%. - A +- e b - A H r s . a .Hm. a. Hrs. a. Hrs. Q. H~s. a. - . a . 0 1-95' 0 1-95' 0 1-95' 0 1-95" 0 1.95' 0 1.95" 1 1.7 1.5 1.7 2.25 1.35 2.5 1.2 2 1.15 1 1.1-1.4 2 1.6 2.5 1-3 3 1.3 3-75 0.95 2.5 1 1.75 0.8 10 1.3 4 1.2 4 1.15 5 0.8 4 0.8 3 0.6 26.5 1.0 5.5 1.0 9 0.9 6 0-8 5-5 0.7 4 0.7 48 0.75 7.5 0-8 20 0.55 7-5 0.7 20 0.6 7-5 0.7 10 0.7 9.8 0.7 29 0-7 9 0.7 23 0.6 33-5 0-5 44 1.0 23 0.65 73.5 0-8 53 1.1 114 1.1 260 1.8 400 1-8 The reversion of the rotation to practically the initial value is clearly evident in the experiments with 2% and 2.53% H a while the minimurn specific rotation in all cases is about 15" 2742 Gn;CfFB;fST AND PURVES GLYCEROL GLUCOSIDE. Condensation of G l w e math Glycerd in presence of Fructose.-The optical behaviour of solutions containing glucose and fructose in acid glycerol was studied by methods similar to those described in detail in the case of glucose alone.Solutions containing equal weights of both sugars dissolved in anhydrous glycerol possessed initially a specific rotation of - 21" to - 22" the corresponding value for the ketose alone being from - 96" to - 97". Dry hydrogen chloride was then introduced as already described until the acid concentration wm 1.5%. C.C. of Fehling's solution. 10.3 G. of 3% glucose solution reduced ............ 10.3 G. , fructose solution reduced ......... Sum of final reducing powers ........................ 10.6 G. of 3% glucose-3% fructose solution reduced ................................................ 10.15 G. of 1.5% glucose solution reduced ......10.15 G. , fructose solution reduced ...... Sum of final reducing powers ........................ 10.3 G. of 1.5% g l u c o ~ e - l - 5 ~ ~ fructose solutioii reduced ................................................ Initially. After 23 hours. 60 21.5 60 1.5 23 120 22.6 30 10.2 30 0-5 10.7 60 10.3 Observed Rotations I = 1 t = 15". In each case the sugars were dissolved in 100 g . or 80 C.C. of glycerol. S o . 1. Fructose 3?/, HCI 1.3;;. Hours 0 1.25 2 3.25 5.5 8.5 19 23 a - 3-6O - 1.25" - 1.20 - 1.3" - 1.50 - 1.70 - 2.20 - 2.40 [a] -96" -33.3" -32" -34.7" -40" -45.3" -58.To -64" Xo. 2. Fructose 1-50//, HC1 l-59;//,. Hours 0 2.5 3-25 4 5.5 10 21 a - 1.8' - 0.7"f - 0.65" - 0.650 - 0.70 - 0.850 - 1-10 [a] -96" -37.3"? -34.7' -34.j" -37.3" -45.3" -58.7" No.3. Glucose 3:/, fructoss 3?& HC1 1G./,. Hours 0 1 2 3 4 6 8 22-5 a - 1.6" +ve. - 0.20 - 0.4" - 0.50 - 1-40 - 1.50 - 2.40 [a] -21.3" +ve. - 2.7" - 5-3" - 6.7" -18.7" -20" -32" No. 4. Glucose 1.50;/, fructose 1.5" HC1 1.5"/. Hours 0 2 3-75 3-5 4.3 6 10 21-5 a - 0.8" + 0.2" + 0.1" + 0.05' 0.0" - 0.25" -0*453 -0.85" [a] -21.3" + 5.3" + 2-6" + 1.3" 0.0" - 6.5" -12" -22.7' No. 5. Fructose 376 HC1 1*5:& moisture. Hours 0 0.5 0.76 1-0 1.5 2 3 5 a - 3-6" - 1.0" - 1.0" - 1.0" - 0.8" - 1-10 - 1.45 - 1.6" [a] -96" -26.7" -26.7" -26.7" -21.3" -20.3' -27.33 -42.7 Hours 9 23 a - 2.20 - 3.00 [a] -58.7" -80-0" Blackening GILCHRIST AND PURVES GLYCEROL GLUCOSIDE. 2743 up-DamethyZ GZyceroZ.-z~-Dibromohydrin was prepared by Michael and Norton's method (Amer.Chern. J. 1880 2 18) 20 g. of ally1 alcohol giving 51.4 g. of product b. p. 110-112"/15 mm. To this were added 11 g. of sodium dissolved in methyl alcohol. Sodium bromide was immediately deposited. The reaction pro-ceeded slowly initially but afterwards suddenly became very rapid the methyl alcohol boiling vigorously. (It is possible to control the reaction if the solutions are dilute and the mixture is kept initially in ice-cold water for several hours. Completion of the reaction is ensured by heating for a considerable time as other-wise it is extremely di6cult to remove the last traces of bromine.) After neutralbation with carbon dioxide the dimethyl glycerol was extracted with ether and distilled as a clear colourless liquid, Dimethyl glycerol C5H1203 requires [R& 30.10 (Found C, 49-4; H 9.8.C5Hl2O3 requires C 50-0; H 10.0%). of ethyl tartrate and nicotine in up-dimethyl glycerol as solvent = + 11.22' (c = 13.37) and - 152.94" (c = 13-46) respectively. y- Benzoyl ap-Dimeihyl Glycerol.-The benzoate was prepared by the standard method. Dimethyl glycerol (3.6 g. ; 1 mol.) was acted on by 7.5 g. of benzoyl chloride (1.67 mols.) and 2.9 g. of sodium hydrosde (2.5 mols.) in 10% solution at + 5' to - 5". The product isolated by extraction with ether was a fairly mobile oil, b. p. 162"/12 mm. nD 1-5075 (Found benzoic acid 50.0. Benzoyl dimethyl glycerol C1,HI6O4 requires benzoic acid 54.5%). ap-Dimethyl Glycerol M&te.-Malic acid (4 g.; 0.6 g. in excess of 1 mol.) was esterified with 6 g.of dimethyl glycerol in presence of gaseous hydrogen chloride a t room temperature. The product was poured into a large quantity of water neutralised with barium carbonate filtered and the filtrate extracted with ether for several hours. The ethereal solution was dried the solvent evaporated, and the residue distilled (yield 5.6 g.). The ester b. p. 2OOo/0-5 mm., is a viscous oil insoluble in water or alcohol but readily dissolved by chloroform. Attempted Preparation of cry-Dimethyl G1ymroZ.-ay-Dichloro-hy& wit8 obtained in the manner described by Smith (Zoc. cit.), b. p. 175-5-176"/733 mm. nD = 1.4827 whilst the treatment with sodium methoxide was carried out as in the case of the ap-isomeride. The identity of the product with afi-dimethyl glycerol is referred to in the introduction.p-.MonometAyl uy-Dic~ohydrin.-uy-Dichlorohydrin (1 1.3 g. ; 1 mol.) wit8 dissolved in 56.8 g. of methyl iodide (4 mols.) and methyhted in the usual m w e r by the addition of 46-4 g. of silver oxide (2 mols.). The reaction which was spontaneous was b. p. 69*5-70.5"/15 mm. nD 1.4219 &? = 1.016 [R& 30.02. [u]:' in chloroform = - 10-60" (c = 9.05) 2744 GILCHRBT AND PURVES GLYCEROL GLUCOSIDE. continued by warming on a water-bath under a reflux condenser for 8 hours an additional 10 C.C. of methyl iodide being added when the mixture became pasty. Ether was used as the extracting agent. The product was a clear colourless liquid (11 g.) b. p. 58"/14 mm. nD 1.4560 (Found Cl 49.7. Monomethyl dichloro-hydrin C,H80C1, requires C1 49065%).Attempted Prepradion of p-Nonomethyl Glycerol.-p-Monomethyl ay-dichlorohydrin (18-3 g. ; 1 mol.) was heated in 36 C.C. of an aqueous alcoholic solution of 29 g. of potassium acetate (2 mols. and 15% excess) in a sealed tube a t 120-140" for 12 hours. The potassium chloride that separated was removed the filtrate evapor-ated to dryness and the residue extracted with ether. On distil-lation of the ether monomethyl glycerol diacetate remained. This was hydrolysed by boiling with barium hydroxide solution for an hour neutralising with carbon dioxide and taking to dryness. The monomethyl glycerol was extracted with chloroform and dis-tilled. The product undissolved by ether was also extracted with chloroform and yielded a further quantity of monomethyl glycerol which had been produced by hydrolysis during the heating process.The monomethyl glycerol obtained was the a- and not the p-, form; b. p. 110-112"/11 mm. nD 1.4462 (Found C 45.2; H 9.4. C,H,,-,O requires C 45.3; H 904%). Trimethyl Glycerol.-The methyl sulphate reaction was the most satisfactory in the case of glycerol and one typical preparation is described. To 20 g. of glycerol (1 mol.) were added drop by drop, 186 C.C. of methyl sulphate (4.5 mols.) and 186-7 g. of sodium hydroxide in 40% solution. At first the usual method of procedure was adopted the methylating reagents being allowed to react with the glycerol at 60-70" the excess of methyl sulphate being destroyed by heating to 100". Under these conditions however the yield of methylated glycerol was very small.Afterwards the reaction was carried out in a flask provided with a mercury seal and attached to a condenser ; trimethyl glycerol and water then formed a volatile mixture which boiled vigorously during the final heating a t 100". The following process was therefore adopted After destruction of the excess of methyl sulphate the mixture was heated in a brine bath; a mixture of water and trimethyl glycerol distilled steadily at 92". This was saturated with sodium chloride and extracted with ether. On drying the ethereal solution with calcium chloride a large aqueous layer separated showing that ether water and trimethyl glycerol form a homogeneous system. The ethereal layer was separated from the calcium chloride solution dried over solid caustic soda and finally over sodium wire.This treatment has the added advantage of eliminating traces of partly substitute NOTES. 2745 glycerols. Pure trimethyl glycerd was thus obtained as a mobile, refractive liquid b. p. 148"/765.4 mm. ng* 1.4069 dt?* 0.9401, [R& 35.06. Trimethyl glycerol C,H,,O, requires [R& 34-84 (Found C 53.3 ; H 10-2. C,H,,O requires C 53.7 ; H 10.45%). Great dif€iculty was experienced in the analysis of the methylated glycerols and although many variations of the usual combustion process have been employed the results obtained are not yet entirely satisfactory. The figures are however sufliciently close to the calculated values to show that each of the compounds possesses the composition ascribed to it. Determination of the methoxyl content by Zeisel's method leads as has already been pointed out in the case of the a-monomethyl ether (Irvine and Macdonald Zoc. cit.) to the formation of isopropyl iodide in varying amount and therefore cannot be regarded as an accurat'e analytical factor. For purposes of comparison the rotatory power of ethyl tartrate in trimethyl glycerol was ascertained. [a] = 5-99 (c = 13-36). The authors desire to acknowledge their indebtedness to the Food Investigation Board and to the Carnegie Trust for the facilities provided during the foregoing research. They also take this opportunityof expressing their gratitude to Principal Sir James C. Irvine C.B.E. F.R.S. for the invaluable help which he has given. THE UNKERSITY ST. ASDREWS. [Receired October Sth 1925.

ISSN:0368-1645    

DOI:10.1039/CT9252702735

出版商:RSC    

年代:1925

数据来源: RSC

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NOTES. 2745 N O T E S . Sulphonation of 4-Chlorophenol. By JOHN MILDRED GAUNTLETT and SAMUEL SNILES. THE structure of the acid obtained by sulphonating 4-chlorophenol was determined in the following manner. 4-hinoanisole-2-sulphonic acid (Bauer Ber. 1909 42 2110) was converted into 4-chloroanisole-2-sulphonic acid. The chloride of this acid was identical with that obtained by treating 4-chloroanisole with cold chlorosulphonic acid. The same sulphonic acid was obtained by methylating the product from the interaction of 4-chlorophenol with warm fuming sulphuric acid (207L SO,). sodium 4-chloraznisole-2-slphonate MeO=C,H,a*SO,Na separates from hot water in prisms containing 2H,O which are lost a t 120" (Found a 14.7; s 13-2; Na 9-4. C,H60,aSNa requires C1 14.5 ; S 13.1 ; Na 9.4:/,).4-Chloraznisole-2-sulphonyl chloride, MeO*C,H,CI*SO,CI melts a t 104" (Found Cl 29.3; S 13-8. 4 2746 NOTES. C,H503&S requires Cl 29.4; S 13-3%) and the corresponding am& at 154". 4-Chlorocsnisde-2-mlphinic acid MeO-C,H,Cl*SO,H, prepared from the chloride and aqueous sodium dphite has m. p. 116" (Found C 40-8 ; H 3.5. C,H,O,ClS requires C 40.7 ; H 304%). 4 - C h l o r ~ n i s o l e - 2 - m l p ~ n e ? MeO*C,H,Cl=SO&e, prepared from the sodium sulphinate and methyl sulphate separates from hot water in plates m. p. 94" (Found C 43-5; H 4.1. C8E&,03c1S requirw C 43-5; H 4.1%). 4-Chloro&nisoZe-2-di-sdphside (MeOaC6H,Cl),S2O, was obtained from the sdphink acid and dilute hydriodic acid m. p. 124-125" (Found C 44.0; H 3.3.CI4Hl2O4C& requires C 44.3; H 3.2%). 4-chEoro-ankok-2-mercapt MeO*C6H3~*SH obtained from the sulphonic chloride by reduction with tin and hydrochloric acid formed small plates from alcohol m. p. 42" which are volatile with steam (Found : C 48.4; H 4.0. C,H,OClS requires C 48.1 ; H 4.0y0). 4-cl'rcloro-anisole 2-disuZphide ( MeO-C6H3C1),S, formed colourless needles from alcohol m. p. 105" (Found C 48.3; H 3.4. C,,H1,0,Cl~S, requires C 48.4 ; H 3.4%).-Kma's COLLEGE LONDON. [Received, October 3rd 1925.1 2 - m - X ylidino- 5 - ethox y -4 5 -d i hydrot hiazole . By VISHVLV ATH ~ H N A NIMKAR and FRANK LEE PYMAN. MARCKWALD (Ber. 1892 25 2355) states that acetalyl-m-xylyl-thiocarbamide yields on treatment with strong sulphuric acid a base CI3GO2N2S m. p.94-95' giving a picrate, m. p. 143-144". Burtles Pyman andRoylance (this vol. p. 581) con-firmed the composition of the picrate for which they found the m. p. 142-143" (corr.) but did not obtain the base in a crystalline stake. They expressed the opinion that if Mmckwald's analyses were correct the base contained a molecule of water of crystallisation. After several months the base regenerated from the picrate isolated by Burtles Pyman and Roylance became crystalline and separated from alcohol in large prisms m. p. 102-103' (corn.) which were anhydrous (Found C 62.6 62.4; H 7.0 7.3; N 11.3. C1,Hl8ON2S requires C 62.4; H 7.2; N 1102%). The base has, therefore the expected composition Cl,Hl,0N2S and is doubtless 9-m-xylidino-5-ethoxy-4 5-dihydrothiazole. The picrate prepared from the pure base had m. p. 152-154" (corr.) (Found C 47.5; H 4.4. Calc. C 47.6 ; H 4.4%) and it thus appears that neither base nor picrate had been obtained previously in a pure state.-MUNICIPAL COLLEGE OF TECHNOLOGY UNIVERSITY OF MAN CHESTER. [Received September 30th 1925.1 c 13H1 ,ON@ ,c6E30 7N3

ISSN:0368-1645    

DOI:10.1039/CT9252702745

出版商:RSC    

年代:1925

数据来源: RSC

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THE HEAT OF COMBUSTION OF SALICYLIC ACID. 2747 CCCLXXV1.-The Heat of Combustion of Salicylic Acid. By ENDRE BERNER. BENZOIC acid naphthalene and sucrose are the substances generally used for the determination of the heat capacity of a bomb calori-meter. A number of recent excellent investigations have shown, however that only benzoic acid fulfils the requirements of a calori-metric standard. This acid therefore has been accepted as the sole standard substance for calorimetric work; its heat of combustion has been fixed at 6324 calories (15") per gram weighed in air or 6319 calories (15") per gram (vac.) (" Comptes Rendus de la Troisidme ConfGrence Internationale de la Chimie," Lyon 1922 p. 54). International acceptance of one or more other substances as secondary standards is highly desirable because the use of a single substance involves a certain risk of introducing an error in the value of the heat capacity of a calorimeter.Verkade and Coops (Rec. trav. chim. 1924 43 561) recently proposed salicylic acid as a secondary standard substance. They determined its heat of combustion and tested its applicability as a thermochemical standard but unfortunately they failed to take the precautions necessary to secure the utmost purity of their samples. The author has now determined the heat of combustion of the pure acid. Three different preparations of salicylic acid (Merck, Kahlbaum and von Heyden) were separately purified partly by crystallisa;tion from different solvents and partly by sublimation in a v&cuum until the heats of combustion of the products were constant; the values obtained 5233.8 5233.8 and 5233.9 cal.(15") per gram (vac.) were identical within the limits of experimental error. From the results of twenty experiments made with these samples, the mean value 5233.8 cal. (15)" per gram (vac.) was found for the heat of combustion of salicylic acid at constant volume. To this corresponds the value 5237.4 cal. (15") per gram weighed in air against brass weights. The ratio of the heats of combustion of benzoic acid and salicylic acid is 6319/5233.8 = 1.2073 (vac.). Verkade and Coops (Zoc. cit. p. 571) found a slightly higher value for the heat of combustion of salicylic acid vk. 5238 cal. (15") per gram (vac.) and consequently the ratio 1-2066. The discrepancy may be due to an error in the heat capacities of the calorimetera or to a difference in purity of the acids.The first explanation is highly improbable because both Verkade and Coops and the author used VOL. CXXVII. 6 2748 BERNER : benzoic acid from the Bureau of Standards Washington for the calibration of their calorimeters and obtained almost the same value [V. and C. 5238.1 ; B. 5237.1 cal. (15") per gram (vac.)] for the heat of combustion of Merck's salicylic acid (" Praparate von beatimmter Verbrennungswarme "). Verkade and Coops used salicylic acid from four different sources. Because the heats of combustion of those preparations all agreed and one of them-Mercks-gave the same value after a single recrystallisation from ether the authors contend that their preparations were '' absolutely pure." These facts however are of no practical value as proofs of the purity of their preparations.The combustion of salicylic acid (about 0-SO g.) in oxygen at a pressure of 35 30 or 25 atmospheres is complete; neither carbon monoxide nor the slightest trace of soot nor any smell due to products of incomplete combustion can be detected. Moreover the acid is neither hygroscopic nor volatile and is easily pressed into pellets which ignite readily. It should therefore be particularly suitable as a st'andard substance for calorimetric work. E X P E R I M E N T A L . Detailed descriptions of the calorimeter the method and the experimental results will be published elsewhere. The calorimeter was of the form recommended by the Bureau of Standards Washington (Bull.1915 11 189). The calorimetric bomb had a thick h e d gold lining and a capacity of about 300 C.C. Temperature measurements were made with a platinum resistance thermometer. The resistance was measured by Kohlrausch's method (" uebergreifende Nebenschlusse ") as used by Jaeger and von Steinwehr (Ann. Physik 1906,21,23) and by Fischer and Wrede (Sitzungsber. Prtuss. A M . Wiss. Berlin 1908 5 129). The cooling correction ur was calculated from the formula ur =a& (u - u,)&, in which a is the constant of the calorimeter u its temperature, u, the convergence temperature and t and t, respectively the time at the beginning and the end of the main period. The numerical value of the integral was in every case determined graphically.In some cases the cooling correction was also computed by the practical method developed by Dickinson of the Bureau of Standards (Zoc. cit. p. 229). This method gave practically the same values as those obtained by the complete computation and therefore may be used even in work of high precision. The total rise of temperature during a combustion was abou THE HEAT OF COMBUSTION OF SALICYLIC ACID. 2749 1". The temperature of the jacket was always regulated so that the cooling correction amounted to 2-3 parts in 10o0. The oxygen w&s prepared from liquid air ; it contained very little nitrogen-the correction for nitric acid was 06--0-7 ca1.-and no combustible impurities. Oxygen from the same source was used for the calibration of the calorimeter and for the combustion of the salicylic acid.Ignition of the substance was effected electrically by means of a very thin platinum wire; the heat developed by the current was about 0.8 cal. If the wire had been merely pressed into the pellet, ignition sometimes failed to occur. A part of the wire was there-fore covered with 06-1.5 mg. of benzoic acid by dipping it in the molten acid and placed close against the top of the pellet; under these conditions ignition never failed to take place. Heat Capacity of the Calorirneter.-This was determined by the combustion of two samples of benzoic acid (a) a standard sample (39b) obtained from the Bureau of Standards Washington and ( b ) a sample (517) purified as follows Benzoic acid (Kahlbaum's '' Praparate fur kalorimetrische Bestimmungen " ) was distilled twice at a pressure of 10 mm.of Hg crystallised twice from benzene and once from carbon disulphide finely powdered and dried for 3 days in a vacuum over phosphorus pentoxide. With 3700 g. of water in the calorimeter vessel 1 g. of water in the bomb and an oxygen pressure of 30 atmospheres the heat capacity was found to be 4066-3 calories (15") at a mean temperature of 18". To this value must be added a small correction for the differ-ence in heat capacity of the products of combustion and the oxygen necessary for the combust'ion. In some recent experiments the variation of the heat capacity with temperature was determined directly ; the heat capacity decreased by about 1 cal. for an increase of 1" a t 18".If the mean temperature during an experiment differed from 18" a correction for the divergence wits applied. Purificatioib of the Salicylic Acid.-1 . Merck's salicylic acid (" Priiparate von bestimmter Verbrennungswarme ") wit8 finely powdered and dried for 3 days in the way described above (sample 57 1). The same preparation was crystallised twice from water and once from chloroform powdered and dried for 3 days (sample 571 IIa). It was then dried for 6 days (sample 571 IIb) and sublimed in a vacuum (sample 571 III). 2. Salicylic acid (Kahlbaum D.A.B.5) was crystallised once from water sublimed in a vacuum crystallised once from chloroform, powdered and dried for 3 days (sample 572 In). This sample was then crystallised once from water once from benzene and 6 A 2750 THE HEAT OF COMBUSTION OF SALWYIXC ACID.once from chloroform powdered and dried for 3 days (sample 572 IV). 3. Salicylic acid (von Heyden's "Acidum Salicylicum volum. puriss.") was crystallised twice from water and once from chloro-form and dried for 3 days (sample 573 11). This sample was crystallised once from water once from chloroform and dried for 3 days (sample 573 111). TABLE I. Benxoic Acid. p = pressure of oxygon in atms.; h = heat capacity in cal. (15') of the calorimeter at 18O and 30 atms. of oxygen; d = deviation from the mean heat capacity in parts per 10,000. Sample. p. h. d. Sample. p. h. d. 39b 30 4066.7 +1*0 517 40 4066.6 +Om7 9 9 , 4065.6 -1.7 Y 30 4065.8 -1.2 Y , 4066-7 +1-0 ? , 4066.6 +O-7 35 4065-2 -2.7 Y 9 , 4066.2 -0.2 5 i j 30 4066.9 + l a 5 9 ) 4066.9 + l a 5 Mean 4066.3 TABLE 11.Salicylic Acid. p = Pressure of oxygen = 35 atms.; t = mean temperature; Q = heat of combustion per gram (vac.) in c a l (15"); D = deviation from mean heat of combustion in parts per 10,OOO. Salicylic acid (Merck) . Sample. t . Q. D. 571 18.0' 5237.3 +0.4 9 18.0 5236.4 -1.3 ,* 18.3 5237.3 40.4 Y 18.1 5237.0 -0.2 ?* 18.1 5237.3 $0.4 Mean 5237-1 Salicylic mirl (Merck) purified. 571 IIa 18.1" 6234-6 +1.5 57i'IIb 18-2 5233.3 -1.0 , * 18.1 5233-9 +Om2 , t 18.0 5232.9 -1.7 671 III 18-1 5234.5 +1-3 , 18.0 6233.1 -1.3 , 18-0 5234.4 +1*1 Mean 5233-8 18.1 5233.3 -1.0 * p = 30 atms. NORGES TEKNXSKE HOISKOLE, TBONDHJEM NORWAY. Salicylic acid (von Heyden) purified. 573 11 18-8' 5234.3 +0.8 17.9 6233.1 -1.5 57,; I11 18.0 62344 +I-0 9 17-9 5234-7 +1-5 Y Y 18.0 5233.2 -1.3 Me- 5233.9 Sample. t. Q. D. Salicylic acid (Kahlbaum), 572 III 18.2" 5234.1 ¶ 18-2 5233-3 18.1 6234.1 57;IV 18.5 6233.7 , 18-5 5234.6 ) 17.9 6233.0 , 18.0 5233-7 Mean 6233.8 purified. + 0.6 - 1.0 + 0.6 - 0.2 + 1-5 - 1.5 -0.2 7 p = 26 at-. [Received July 9th 1925.

ISSN:0368-1645    

DOI:10.1039/CT9252702747

出版商:RSC    

年代:1925

数据来源: RSC