BENNETT m HOCK ~‘-DIHLOBODIPBOPYL SULPEIDE 2671 CCCLXV .-+- Dichloro&iprop yl Sdphide. By GEORGE MACDONALD B~nnmrr and BLF~ED Loms HOCK. THE remarkable chemical reactivity of @@‘-dichlorodiethyl sulphide muat be attributed to the influenceof the sulphur atom upon the two chlorine atoms. A high degree of reactivity is in fact generally shown by the chlorine atom in compounds of the general fornula R-S*C€&CK&l and there is a correspondingly high reactivity in the hydroxyl group of the pazent compound R*S*W-CX&-OH (compare Bennett J. 1922,121,2140). The isomeric aa’-dichlom-diethyl sulphide (Bales and Nickelson J. 1922 121 2137; Mann and Pope J. 1923 123 1172) readily yields its chlorine when boiled in solution with alcoholic sodium hydroxide; the chlorine is therefore in a reactive condition.No data however are avail-able for a quantitative compazison of the propertiea of chlorine atoms sitmted in the a- and @-positions. ~ ‘ - W h o d i p r o p y Z dphide the first simple chlorosulphid 2672 BEKNETT AND ~ o o g ~ ' - D I ~ O B O D I P B O P Y L SULPIDE. having the chlorine a4nm.h the y-@tion has now been preprtred. It is decidedly less reactive than @p'-dichlorodiethyl sulphide and fip'-dichlorodipropyl sulphide (Coffey J. 1921 119 94; Pope and Smith M. 396). It waa prepared from ~'-d&ydroxydipopyi &phi& obtained by the acfion of sodium sulphide on +doropropyl alcohol but the replacement of the hydroxyl groups in the dihydroxy-sulphide by chlorine was as exceptionally difEcult as the analogous reaction is surprisingly easy with 9-hydroxy-sulphides.Whereas the latter operation is complefed in a few minutes by boiling con-centrated hydrochloric acid (Clarke J. 1912 101 1583; Coffey, loe. cit.) replacement of the hydroxyl groups of w'-dihydroxy-dipropyl sulphide did not occur when any of the usual reagente such as hydrochloric acid phosphorus tri- or penta-chloride or phosphorus tri-iodide were employed and hydrogen chloride at 150" reacted only slowly to give a poor yield of chloro-compound. The hydroxyl groups in this sulphide are therefore less reactive than is usual in a primq alcohol. The use of thionyl chloride alone gave no better result but the dichlorodipropyl sulphide waa obtained wily in good yield when this reagent waa used in presence of dimethyladine (Damens Compt.rend. 1911 152 1314). The ditlerence in charmter of the p- and the y-chlorine atoms ia well shown by the action of potassium cyanide in alcoholic solu-tion upon pp'-dichlorodiethyl and yy'-dichlorodipropyl sulphidea . Whereas Davies has shown that the former is converted into an unexpected substance of the formula C6H1,S,(CN) (J. 1920 117, 298) we find that the latter is smoothly converted into the dinitrile of thiodibutyric acid (Gabriel Ber. 1890 23 2493). A study of the oxidation of yy'-dichlorodipropyl dphide showed that the sulphur atom in the molecule hrts unusual properties. Although the action of sodium hypobromite nitric acid or hydrogen peroxide upon the sulphide at laboratory temperature might be expected to furnish a sulphoxide these reagents produced the same compound which resulted from oxidation with chromic anhydride in boiling glacial acetic acid namely the mJ$one, of m.p. 66". It thus appears to be a property of the sulphide to take up two atoms of oxygen per molecule instead of one. More-over neither a sulphilimine nor a mercurichloride could be obtained from it and ite dibromide which can be prepared only in the presence of a very large excess of bromine is even more unstable than the dibromide of pp'-dichlorodiethyl sulphide so that there seems to be a general reluctance to form derivatives involving quadri-valency of the sulphur atom. A comparison o€ the rates of reaction of pp'-dichlorodiethyl and SO2(CH2-CH,CH2C1), BENXEFC AND HOCK ~Y'-DI~ORODIFBOPYL SULFHIDE.2673 yy'-dichlorodipmpyl adphinee with sodium hydroxide in ethyl alcohol ahowed that the course of the two reactions being assumed fo be s.im.&w the former r w t a sixty the8 &8 fa& as the latter. We hope fo make a sysfematic comparison of these and other chloro-sulphidea when a synthesis of a 8-cblom-mlphide has been com-pleted. E X P E R I Y E N TAL. Adion of So&iu7n Sdphiri&e 012 y-Chhmpqy1 AhM.-A solution of sodium sdphide (95 g. Na$,SI&O) in an equal weight of w a k waa added cautiously in three portions to y-chloropropyl alcohol (60 g.) the mixture heafed under reflux for 3 hours and then dis-tilled with steam until the distillate no longer gave a whih precipi-tate with mercuric chloride. The distillate was boiled with an excea of yellow mercuric oxide filtered concentrated and cooled; B small quantity of the mercupt& of y-hydmxypopyl mermptan, Hg(S°C3H6*OH), then separated out.It crystabed from wbutyl alcohol in silvery plates m. p. 132-134" (Found Hg 52.9. CBE,,0,SJ3g requires Hg 52.5 %). The solution remaining in the distillation fiask was made acid with hydrochloric acid and concentrated on the steam-bath. The bulk of the sodium chloride wa8 removed by filtration after dilution with acetone the solution dried and the acetone evaporated. The residual viscous oil was heated in a current of dry air at 100" under diminished pressure and finally poured off from a little sodium chloride which it deposited from solution. w a Viscous oil which could not be distilled or induced to crystallise, and wa8 not analysed.With phenylwbimide it reacted at once to give the bisphenylurethune S(C,H,*O*CO*NHPh), colourlem needles from benzene m. p. 146-148" (Found C 62-1 ; H 6.5. C&04NS requires C 6143 ; H 6.2%). Action of Thionyl Chloride P h m p h Halida and Hydrogen Cliloride upon yy'-Dihydroxydiprol>yl Sdph&.-The dihydroxy-sdphide waa not appreciably affected by heating for 2 hours with boiling concentrated hydrochloric acid. The action of thionyl chloride phosphorus tri- or penta-chloride or phosphorus tri-iodide led to the production of non-volatile substances which were pre-sumably esters of the correspon- hydroxy-acids. For example, after the dihydroxy-compound had reacted in presence of dry benzene with phosphorus tri-iodide (213 mol.) the material recovered aad when kept in a desiccator it slowly hardened to a resinous ma88 without crystallising an odour of mustard being simulfaneously developed.~ ' - D i h y d r o x y d i p r ~ y l dphide S(C,H,*OH), ww thus obtained from the solution could not be distilIed under dimirriRh ed P=-, VOL. CXXVII. 4 2674 BENNETT AHD HOCK yy'-DIOHLOEODIPROPYL SUISHIDE. The replacement of the hydroxyl group was h t achieved as follows the dihydroxypropyl sulphide wm heated a t 150-160" while a stream of dry hydrogen chloride was p d inb it for 2-6 hours. The product was distilled; a small quantity of an oil, b. p. 135-150"/25 mm. waa obtained which consisted of prsctically pure dichlorodipropyl sulphide (yield 17 yo). yy'-DiehZorodipropyZ SzclpiCide.-Thionyl chloride (80 g .) was added drop by drop to a well-cooled mixture of y~'-dihydroxy-dipropyl sulphide (45 g.) and dimethylaniline (80 g.) kept below 60".The mixture was then heated a t 100" for + hour poured into an excess of dilute hydrochloric acid the oil extracted with chloro-form and the extract washed with water dried and distilled. yy'-Dkhlurodipropyl sulphide S(C,H,Cl), was thus obtained as a faintly yellow oil of pronounced dour b. p. 162"/43 mm. (yield 83%) (Found C 38.9; H 6-5; C1 38.2; S 16.7. C,H1,C@ requires C 38.5; H 6.3; C1 37-9; S 17.15%). The following constanfs were determined OF (vac.) = 1.175 n i = 1.5075, whence mL] = 47.42 (calc. 47-25). The liquid did not crystal-lise when cooled to the temperature of liquid air and allowed to revert slowly to normal temperature.Compound with Platinic Chloride.-Thia was obtained in greenish-yellow plates m. p. 83-5-85" by adding platinic chloride (0.86 g.) in acetone to the chloro-sulphide (0.46 g.) also dissolved in acetone (5 c.c.) the product crystallking in the course of a few hours. It had the composition 2S(C,H6C1),,PtC1 (Found : Pt 27-7. An unstable dibromkk s(C3H6c1),Br2 was obtained from the chloro-sulphide (0.94 g.) with bromine (4 g.) in carbon tetrachloride (5 c.c.). The crystals were quickly filtered off washed with a little of the pure solvent dried on porous tile and analysed at once since the substance decomposed completely when kept over-night (Found : Br 57.7. C,Hl,Cl,Br2S requires Br 5943%). Repeated attempts to prepare a sulphilimine led only to the isolation of toluene-p-sulphonamide m.p. 137" (Found C 48.8; H 5.3. Calc. C 49-1; H 5.3%). Action of Methyl lodide.-When the chloro-sulphide was mixed with methyl iodide (5 mols.) crystals appeared in the liquid within hour of m. p. 179-181" but a sufEcient quantity for analysis could not be collected. I f left in the liquid the crystals soon redissolved and a viscous oil separated. This oil was almost entirely aoluble in water but the solution deposited an oil again on evapor-ation m d hociation of the sulphonium compound evidently took place with liberation of the original sulphide. The residue obtained by evaporating the excess of methyl iodide from the original mixture C1,H,Cl,SPt requires Pt 27.4%) BEKN-S~T ~ K D HOCK ~~'-DICHLOBODYPBOPYL SUISHIDE.2675 could not be induced to mlidify but it readily combined with mercuric iodide to produce a mlid which c e from acetone chloroform in yellow needlea (the chlom-sulphide ifself is quite indif€erent to mercuric iodide). After three recrgsfallisations the substance had m. p. 84-88' and analysis showed it to be di-c ~ o d i ' p ~ Z m e t l b y ~ h o n ~ ~ m mermri-iodide (C,H,Cl)@MeI,HgI, (Pound Hg 27-1 ; C,H15C&SHg qnireS Hg 25.65; AgCl + AgI 126.5%). This compound was evidently not quite pure but further purification was not possible since &-sociation of the substance occurred in solution an odour of the original chloro-sulphide being always developed during recrystsl-hation. Addon of Ozidbing Agenta.-The chloro-sulphide wm shaken with an ice-cold solution of sodium hypobromife (1.8 mols.) the mixture heated at 50" for 5 minutes and hally cooled in ice ; the oil obtained solidified fo a mass of crystals which were recryatallised from benzenelight petroleum.This substance was yy'-die7ilmdipmZ-d p h (C&H,Cl),SO, m. p. 65-66" (Found C 32-7; H 5-6; Cl 32.4. C,H,,O,CL# requires C 32.9; H 5.5; C1 3204%). It is appreciably soluble in water and readily soluble in most organic solvents with the exception of light petroleum. In view of the unexpected nature of this product the analyses were repeated-with similar results. The substance was also produced when the chlom-sulphide was (i) dropped into a mixture of fuming (2 vols.) and con-centrated (1 vol.) nitric acid cooled in a freezing mixture; (ii) dissolved (0-94 g.) in glacial acetic acid (2 c.c.) mixed with hydrogen peroxide (0.7 g.in 2 C.C. of 60% acetic acid) slowly with cooling and kept at laboratory temperature for 48 hours; and (iii) heated for 2 hours in boiling glacial acetic acid with chromic anhydride (twice the calculated amount to produce a sulphone). yy'-DiphmwxydipropyZ Sdphid-e (PhO*GH,),S.-The chloro-sulphide (1.2 g.) was heated at 180" for 2 hours with phenol (6 g.) and sodium ethoxide (from 0-3 g. of sodium). The mixture was m d e acid and distilled with s h m . The residual oil solidified when washed with a little aqueous alkali and was then recrysta,llised from methyl alcohol; m. p. 45" (Found C 71-35; H 7-4. Cl,E,0&3 reqnires C 71-35; H 7.3%).yy'-Di-p-tolybxydiprqyl sulphide prepared in a similar way from jp-craol had m. p. 5(&52" (Found C 72-9; H 7.9. C A 6 0 # requires C 72.7 ; H 799%). Action of Piperidine on the Chloro-sulphide.-When a midm of the chloro-sulphide with piperidine (8 mols.) was kept for 24 hours, cryatah of piperidhe hydrochloride separated out. The mixture waa made alkaline and distilled with &am. The residual oil 4u2 AgCl + AgI 123.7 2676 BENKETC AND HOOK ~~'-DICXELORODIPZ~OPYL SULPE~E. waa removed in ether the extract dried and evaporated when yy'd@p&didiprqqZ mdph& (C6H1,,N-CsIj[6)&3 waa left as an oil which did not crystalhe. It readily yielded a picrate which crystabed from methyl alcohol in yellow needles m. p- 199-200' (Found C 45-3 ; H 5-8.c28~8014N8s requires c 45.3 ; H 5.2%). Action of Potassium Cyankde.-The chloro-sulphide (1.87 g.) ww heated in boiling ethyl alcohol for 9 hours with potasaium cyanide (2 g. = 3 mols.). The alcohol was evaporabd water added the precipitated oil removed in ether and the ether evaporated. The crude dinitrile thus obtained wa,s at once hydrolysed by boiling with concentrated hydrochloric acid (15 c.c.) for 2 hours. The cold diluted solution was extracted several times with ether and the extract on evaporation left a solid (0.8 g.) which waa crystabed once from a little water and once from benzene-light petroleum. Thirr substance was thiodibutyric acid of m. p. 99-101" (Gabriel, loc. cit. and Davies J. 1920,117,297) (Found by titration equiv., Adion of Potiz.!?aium SuZphide.-The chloro-sulphide (4.0 g.) was heated for 3 hours with a boiling ethyl-alcoholic solution of freshly prepaxed pobsium sulphide (from 4.8 g.of potassium hydroxide); the mixture was then distilled with steam. The residual oil which solidified on cooling crystallised from carbon disulphiddight petroleum as a white powder melting indefinitely between 50" and 70". Repeated crystallisation failed to separate any substance of sharp melting point. This material although evidently not a pure chemical individual had approximately the composition of a polymeride of IkxumdhyZene disulphide (Found: C 48-0; H 8.4; M cryoscopic in camphor 1400 1740. C,H,,S, requires C 48-65 ; H 8-1 % ; M 148). It closely resembles the " polymeric " diethylene disulphide which reaults from the action of alkali sulphides upon ethylene dibromide or dichlorodiethyl sulphide and both axe probably mixtures of substances having a long open-chain structure (compare Bennett and Whincop J., 1921 119 1861; Staudinger Hdu.Chim. Acta 1925 8 67). C m p a ~ m with pp'-Dichlorodiethyl Sulphide with rmpect to Speed of Reaction with Ahholic Sodium Hydroxide.-A solution of dichloro-diethyl sulphide in ethyl alcohol (10 C.C. ; 0-23 mol. per litre) was added to boiling alcoholic sodium hydroxide (25 C.C. ; 06115N) and the mixture boiled under reflux. It was found by titration that after 5 minutes the reaction had completed itself to the extent of 71.5%. An approximately equivalent solution of yy'-dichloro-dipropy1 sulphide (10 C.C. ; 0.25 mol. per litre) ww mixed with the m e volume of the same solution and boiled for 5 hours ; the reaction had then completed itself fo the extent of 71.7%. 105. WC. 103.1) We wish to express our thanks to the West Riding County Council for a echolamhip which has enabled one of us (A. L. H.) to take part in this inveatigation and to the Chemical Society for a grant which has defrayed much of the expense involved. T€i3Z UNIVERSITY SEKEFFIELD. [Received September lst 1925.