126 MASSON AND KIRKLAKD ACTION OF BROJlINE AND XVII1.-Action of Bromine and Chlorine on the Salts of Tetrethyl-phosphonium,. By ORME MASSON M.A. D.Sc. (Edin.) and J. B. KIRKLAND. University of Melbourne. THE action of the halogens on trimethylsulphine salts formed the subject of a paper communicated to the Society by Dobbin and one of us (Trans. 1885 56) and in a subsequent commcnication the action of the halogens on tetrnmethylammonium salts was described by the same authors (Trans. 1886 846). In these papers it was shown that the halo'id salts of these bases can combine directly with iodine bromine chlorine or iodine monochloride to form compounds of the general formula RXs (where R is the basic radicle and X is I Br or Cl) ; that those members of the series which contain not less that one atom of iodine in the molecule are fairly stable crystalline solids of a characteristic black red or yellow colour ; that the other members containing only bromine or chlorine or both are red or yellow liquids stable only i n an atmosphere of the halogen from which they have been formed; that some of these unstable com-pounds have a sufficiently definite composition (corresponding t o the general formula RX,) as proved by synthetic experiments ; but tha CHLORINE ON SALTS OF TETRETHYLPHOSPHONIUN.127 P. C. Found (per cent.) . . . . . . . . . . . - 34 -79 ---others have a tendency t o absorb a large excess of halogeii without very great alteration of properties particularly where bromine is the halogen added. It was also shown that this formation of perhnlo’id compounds is an action of wider application than at first would seem probable ; for not only may the nature of the organic basic radicles be varied very considerably but qualitative experiments with the sulphates of trimethylsulphine and tetramethylsmmoniurn showed that these as well as the halo’id salts can combiuc? directly with bromine and chlorine.The striking resemblance between the behaviour in this respect of the sulphates and the chlorides led the authors to reject that view of the constitution of the perhalo‘id compounds which is represented by the formula R’*X<X; and the option was left of regarding them all as molecular compounds of the formula R’.X,X., or of regarding the central atom of the basic radicle (S o r N) as capable of directly attaching to itself the additional halogen atoms (R’”X3).Quantitative data however were required to fully prove the similarity of the action of the sulphates and chlorides or bro-mides. It was thought that more stable compounds might be obtained from the salts of a phospllorus base and a preliminary experi-meiit with tetrethylphospboniuu iodide showed that a t any rate this salt is capable of yielding perhaloid compounds resembling those already studied. The investigation was then interrupted and has only lately been resumed by the present authors. ‘l’etrethylphos-plionium salts have been used on account of the greater ease with whicti they may be prepared as compared with the methyl compounds. The iodide was prepared by HoEmann’s method from phosphonium iodide and absolute alcohol and was proved by analysis to be of suffi-cient purity.x H. I. --7 *39 45-68 ---_-Calculated (per cent.) . . . . . . . In any future experiments however we should prefer the method of preparation described by us in the next paper (p. 138) on account of its greater simplicity and economy. 11 -31 35.03 7-29 46 ’35 A c t i o n of Bromirhe on TetrethlJ1phosphoniunz Iodide. When bromine is added to this salt cotiibin a t,’ ion oc(’urs accpm-paiiied by tlre development of much Lent the wliole pheuouien 128 MASSON AND KIRKLAND ACTION OF BROXINE AND bejng similar to those observed in the cases of the iodides of trimethyl-mlphine and tetramethylammonium. When the resulting heavy red liquid is freed from excew of bromine by evaporation and by washing with anhydrous ether it bright red solid remains which dissolves in warm alcohol and on evaporation may be obtained in orange-red crystals.The appearance and properties of these leave no room for doubting that they are tetrethy lphosphonium dibrorniodide, this was confirmed by analysis. P (C,H,),I Br ; *I. 0.1899 gram gave 0.1450 gram CO and 0-0880 gram H,O; or 0.03955 gram C and 0.00798 gram H. 11. 0.1970 gram gave after redaction with sulphurous acid, 0,2t?OO gram of the mixed silver salts AgBr and AgI Assuming this mixture to be in the proportion 2AgBr AgI, it contains 0.07332 gram 13r and 0-05820 gram I. Found. -7 Calculated for P(CZH5)41Br2. I. - - P 7-18 H 4-61 5-40 1 . 29.26 - 29.54 Br 36.87 - 37-22 c 22.12 21.86 -This dibromiodide like those previously described yields a black explosive substance when treated with aqueous ammonia ; and forms an additive compound of the formula P(C,H,),IBr + 2NH3 whelk subjected to the action of a current of dry ammonia.This com-pound is black in colour. When left exposed to the air it loses ammonia and leaves the dibromiodide as a red powder. 0.1470 gram of the dibromiodide yielded 0.1582 gram of the black ammonia compound. * This dibromiodide the corresponding dichloriodide and the tribromide were found to present unusual difficulties when submitted to combustion-difficullies not met with in the case of tetrethglphosphonium iodide on the one hand or of the perhalo'id compounds of trimethy1sulr)hine and tetmmethplammonium on the other.An open tube was employed with oxide of copper and chromate of lead with silver a t the exit end. The combustions had to be conducted with extreme slowness to avoid loss of phosphine-smelling volatile matter (which spoilt the first experiments), and in every case a refractory black residue remained which yielded only to prolonged heating in the oxygen current. This may account for the high percentages of hjdrogen found though all the usual precautions were employcd for drying the gas CHLORIXE ON SALTS OF TETRETHTLPHOSPHONlUM. 1-29 Increase per cent. Percentage increase of weight. 7-26 7.47 Calculated for P(C2H5),IBr2 + 2NH3. . . . Found . . A synthetic experiment was made in order to ascertain whether, by bromination of the iodide any compound could be obtained con-taining more bromine than the dibromiodide.0.3087 gram of the dry iodide was exposed for three-quarters of an hour at the ordinary tem-perature to a current of dry air laden with bromine vnpour. The iodide was contained in a porcelain boat placed in a glass tube and the boat and tube together with the glass stopper were tared at the commencement. After clearing out the tube with a rapid current of dry air i t was found that there was an increase of weight equivaleiit to a gain of 3.4 atoms of Br by each molecule of Y(C2H5)J. Tlie product was a dark-red liquid. The tube was now placed in a n air-bath and kept a t 110" for two hours whilst the bromine current was kept up and the increase of weight was again ascertained and forind to be equivalent to a gain of 5.2 atoms of bromine by each molecule of P(C,H,),I though there was not much change in the appcbarance of the liquid product.This was then subjected to a current of pure dry air at the ordinarF tempeiature and weighed from time to time. It was soon converted into a bright-red solid substance and this con-tinued to lose bromine slowly but after three hours still retained what was equivalent to 3.6 atoms for each molecule of the iodide. Atoms of Br per mol. Bromine passed. 4 how cold. 1 -Dry air passed. 2 hours a t 11Q '}I - -- - I 3 hours Weight found. -0 '6172 0 * 7827 --0 * 6320 I- -99.8 I 3.4 Nature of product. Liquid. Liquid. Solid. --Weight of iodide used 0.3087 gram.There is t.hen a marked tendency for P(C,H5)J t o take up more than Br2 but if a definite higher compound exists i t is of an unstable nature. It will be seen that the behaviuur of the iodide towards chlorine favours by analogy the supposition that an unstable tetra-brorniodide P(C,H,),IBr, may exist. Action of Chlorine o n Tetrathylp23hosphoniu.m Iodide. The absorption of chlorine by the dry RRlf is atiended by develop-ment of heat and the formation of st substance which a t first brown 130 MASSON AND KIRKLAND ACTION OF BROMINE AND becomes yellow as the action proceeds ; it is facilitated by keeping the salt a t a temperature of about 70° in which case a red liquid is obtained that solidifies to a darkish yellow crjstalline mass on cooling in an atmosphse of chlorine.Its composition was ascertained by the following synthetic experiment which was conducted in a manner similar to that already described :-Weight of iodide taken . 1.011 gram. Chlorine passed at 70” 1 hour. Weight of product (solid) . 1.520 gram. Percentage increase of weight 50.3 per cent. Percentage increase calculated for forma-tion of P(C2H5)JC14 51.8 per cent. This tetrachloriodide very slowly loses chlorine in dry air. but decomposes with loss of chlcrine when treated with water or alcohol. Its alcoholic solution on evaporation yields yellow crystals of the dicliloriodide P(C2H5)JC12 a substance closely resembling the dichlor-iodides previously described both in appearance and in its reactions with ammonia &c. I. 0.1233 gram gave 0.1255 gram CO and 0-075 gram H,O, equivalent to 0.03423 gram C and 0.00833 gram H.11. 0.1586 gram after reduction with sulphuric acid gave O*%W gram of mixed silver salts. On the assumption that this con-tains iodide arid chloride in the proportions of AgI SAgCI, it is equivalent to 0.0576 gram T and 0.0:422 gram C1. On analysis it gave the following results :-Found. Calculated for +-7 Y (CpHb)dIC12. I. 11. - - P . H.98 C . 27.83 27-75 H 5-80 6. i 4 I 36-81 - 36.32 20.30 C1 20.58 ---Action of Bromine om Tetrethy~hos~hoikiunz Bromide. The bromide employed was made from the iodide. by shaking its An estimation of solution with recently precipitated silver bromide. the bromine showed it to be of sufficient purity. Br per cent. Found 54-79 Calculated f o r .. . . . . . . . . . . . . 35.2 CHLORIXE ON SALTS OF TETRETHTLPHOSPHONIUM. 131 A synthetic experiment with this sait showed that when subjected to the action of bromine-vapour a t 110" it absorbs it to form a dark-red liquid which a t the ordinary temperature is converted in to a scarlet, crystalline solid having the composition indicated by the formula P(C2H5j4Hr, that is the bromide is converted into the hoptabromide by addition of six atoms of bromine. The details of the experiment are given in the following table :-Weight of bromide taken Bromine current a t 110". . Weight of product (solid) 0.4554 gram. Increase of weight 209.4 per cent. Increase calculated for P(CzHg)4Br,33i.6. 211.4 per cent. 0.1472 gram. 1 hour.This heptabromide like thg higher compounds derived from the iodide is not stable in air a i d also loses part of its bromine when treated with absolute alcohol. The alcoholic solution yields red crystals of the tribromide P( C2H5),Br3. This compound. closely resembles the dibromiodido but does not form an addition product with ammonia and is dissolved by ammonia solution. No solid tribromides were obtained from trimethylsulphine or tetramethylam-rnoniuru but only unstable red liquids. The difference in behaviour in the present instance may be wholly attributable to the presence of ethyl in place of methyl radicles rather than to the presence of phosphorus in place of sulphur or nitrogen; for Marquardt ( J . pr. Chem. 1 429) obtained a solid tribromide of tetrethylammonium.The following were the results obtained by analysis :-I. 0.2046 gram gave 0.1860 gram COz and 0.1022 gram H20, 11. 0.2645 gram gave 0*2380 gram CO? and 0.1362 gram H,O, 111. 0.18~8 gram after reduction with sulphuric acid gave 0.26'40 equivalent to 0.05073 gram C and 0.01135 gram H. equivalent t o 0.013491 gram C and 0.01513 gram H. gram AgBr equivalent to 0.11234 gram Br. Found. A Calculated for r- I P( C-H,) .&r3. 1. 11. 111. - - - P 8.01 C 24.80 24-79 24-54 H 5.18 5-54 5-72 Br - . 62.01 --- 62-14 100.0 132 RlA4FSON AKD KIRKLASD ACTION OF BROMTNE AND Action of Chlorine o n Tet ret hy 7phosp honium Chloride. The chloride employed was prepared by shaking a solution of the iodide with recently precipitated silver chloride and was thoroughry dried by heating in a current of dry air a t 110".The salt absorbs chlorine and turns yellow ak the ordinary temperature but the action goes better at 105-110". Under these conditions a yellow liquid is obtained which on cooling solidifies to a yellow crystalline mass. A quantitative experiment showed this to consist of the trichloride, P(C2H,),CL Weight of chloride taken Chlorine passed in the cold Chlorine passed a t 105-110" 14 ,, Weight of product (solid). . Calculated increase for P(C2Ha)aCl*C12 0.1172 gram. 2 i hours. 0.1608 gram. 38.9 per cent. Increase of weight 37.2 per cent. The trichloride is a yellow cryst,alline substance which deliquesces in t,he air and is decomposed by water and alcohol with reformation of the chloride.Like other perhaloid compounds it is insoluble in anhydrous ether. There appears to be no tendency to form a. higher addition product than the trichloride. Action of Bromine on Tet,.ethylphos~hon.iuwc Xulphate. The sulphate was prepared from the iodide by means of silver sulphate. In order to thoroughly dry the salt obtained by evapora-tion of the solution i t was found necessary t o heat it for some hours at a temperature ranging from 100" to li0" in a Sprengel vacuum. It was then submitted to the action of bromine vapour in the same manner as the bromide the increase of weight being observed first after bromination at UO" and subsequently after further bromination at the ordinary temperature. It was found that the sulphate has the power of iaking up a large quantity of bromine but that the amount absorbed and the character of the product vary considerably accord-i n g to the temperature.The product formed at 110" is when cold, a red solid ; and the increase of weight in this case corresponds to the formation of [P(C,H,)4]2S04,Br12 ; and this it may be remarked, is analogous to the highest brominated derivative of the bromide, P(C2H5)4Br,Br6 which it closely resembles in its general properties-appearance instabilit,y in air decomposition by alcohol &c. The product formed ar t h e ordinary temperature differs from this being a dark red liquid and containing a still larger amount of bromine. In the two experiments made details of which are given below th CHLORIXE ON SALTS OF TETRETHYLPHOSPHOSIUN.133 increase of weight at the ordinary temperature corresponded closely with that required for the formation of [P(C2H,),),SOa,BrT. ; but it is doubtful whether this really marks the formation of a distinct corn-pound or the extreme limit of bromine absorption. When this highly brominated liquid is left in a desiccator over solid potash or when i t is treated with a current of dry air i t quickly loses bromine and assiimes the solid state; but the decomposition does not stop here, and we have not succeeded in obtaining any brominated sulphate of stability equal to that of the tribromide or the dibromiodide. Experiiri ent. I. 11. Weight of sulphhte used in grams . . 0.2678 0.2192 Bromine passed a t 110" . 1 hour 1 hour Percentage gain of weight .243.8 244.5 Bromine subsequently passed in cold 2 hoiirs 1 hour Weight of product (liquid) 1.4848 1.2207 Percentage gain calculated for [P(C2H5)J]2S04,Br22 451.3 Percentage gain calculated for [ I'(C,H,),]2SOd,Br12 246.2 Weight of product (solid) . 0.9206 0.7.552 Percentage gain of weight . 454.4 4563.9 The solid brominated sulphate dissolves in alcohol and red crystals are formed in quantity when the solution is partly evaporated ; but a study of these and estimations of the bromine proved them to consist of tetrethylphosphonium tribromide. It was proved that the crystals contained no sulphuric acid but the mother-liquor was found to be strongly acid. The alcohol therefore produces deoompositioil and it is interesting to uote that the phosphorus radicle retains the bromine in preference to the sulphuric acid group.I. 0.1196 gram after reduction with sulphurous acid gave 0.176 11. O*U492 gram gave 0.072 gram AgBr equivalent to 0.03064 gram AgBr equivalent to 0.07489 gram Br. gram Br. Found. 7 Calculated for r-L for P(C2H,),Br3. I. 11. Br per cent . 62.01 62.62 62.27 Action of Chlorine on Tetrethylphosphoniuin Xulpphate. The thoroughly dried sulphate combines with chlorine but less readily and (as in other cases) to a less extent than wit,h bromine. The salt turns yellow and if the temperature be raised to 130" while the chlorine is passing. fuses to a yellow liquid which solidifies on cooling in the clilorine atmosphere. In the two experiments made i 134 S-4LTS OF TETRETH VLPHOSPHONIUM. Chlorine on iodide.Alcohol on 3 Bromine on bromide was found that the increase of weioht corresponded to the formation of the compound [P(C2H5)4]2SO~,C14; and this it may be noted is analogous to the formation of the chlorinated chloride P(C2H5),C1,C1,, already described. The sulphate therefore appears to resemble the bromide in its action towards bromine and the chloride in its action towards chlorine both as to the composition and as to the appearance and properties of the products formed. This is in accordance with the previously recorded qualitative observations on the sulphates of trimethylsulphine and tetr:tmethylamnionium. Experiment. I. 11. Weight of sulphate used in grams 0.2172 0.2018 Chlorine passed a t 130". . 14 hours I$ hours Weight of product 0.2964 0.2790 Percentage gain calculated for [ P( C,H5),],S0,,Cl, Percentage gain of weight .36.4 38.2 36.4 This chlorinated sulphate dissolves in water with effervescence due to escape of chlorine deliquesces when exposed to the atmosphere and slowly evolves chlorine when subjected to a current of dry air. Tlie following table contains a list of the polyhaloi'd-derivatives described in this paper together with a summary of the methods of forming them and of their properties. In some cases the fornlulae given are doubtfully indicative of definite compounds. 70" -110" 1 2 . . 3 4 5 . . 6 . 7 8 . . 9 . . 10 Compoiind formed. P(C2H5)41Br4 (3) P(C2H5)JBr2 P(CZH5)4IC14 . P(CZH,),IC12 . P (C2H5),Br,. . P(C2H5)4Br3 P(CzH,),ClS P(CZH6)412S04Br22 (?) . (C2H6)ihS04Br12 - * -P(CzH5),]2SO4C14 Method of forma-tion. tion. -.- -_-Bromine on iodide. 1 cold Alcohol on 1 Bromine on sul-Bromine on sul-Chlorine on sul-phate phtLte phate cold 110" 130 Characters of the compound. Bright red crpst. solid unstable in air. Orange crystals : stable. Dark yellow cryst. mags unstable. Yellow cryst,als, stable. Scarlet cryst. mass : unstable. Red crystals stable. Yellow cryst. mass: Red liquid un-Red solid unstable. unstnble. stable. Yellow solid un-stable