THE ACTION OF CHROMIUM OXYCHLORIDE ON PINENE. 45 VII.-The Action of C7tromium Oxychloride o n Pinene. By G. G. HENDERSON B-Sc. M.A. Assistant to the Professor of Chemistry University of Glasgow and R. W. SMITH. RTARD in studying the action of chromium oxychloride as an oxidis-ing agent (Ann. Chemz. Phys. [S] 22 SlS) found that some of the terpenes yield compounds with this substance which when treated with water give corresponding camphoaldehydes but he merely mentions the fact and gives no description of the camphoaldehydes obtained. It seemed to us of interesh to examine these compounds more fully and for a commencement we took pinene the terpene boiling at 159-161" which we obtained in a state of great purity. Chromium oxychloride attacks pinene with almost explosive violence and therefore in order to moderate the action we employed 10 per cent.solutions of each substance in dry carbon bisulphide. The pinene solution was put into a flask connected with a reflux condenser, and kept cool by a stream of water and the solution of chromium oxychloride was added in small portions by means of a dropping funnel. After each addition of the chromium oxychloride a voluminous dark-brown precipitate was formed and quickly settled to the bottom of the flask. When all of the reagent had been added 46 HENDERSON AND SMITH THE ACTION OF the flask WM allowed to remain for some time until the precipitate had settled; the carbon bisulphide was then filtered off as rapidly 8s possible by aid of the pump the precipitate washed with dry carbon bisulphide dried at a gentle heat and put into dry well-stoppered bottles.The solid compound thus obtained is almost black when moist but when dry it is of a light greyish-brown. When exposed to the air it rapidly absorbs water and decomposes and when heated to between 80" and 90" it loses 1 mol. of hydrogen chloride with slight explosion. Analysis of the compound gave the following results :-I. 0.3710 gram substance gave 0.5594 gram carbon dioxide = 0.0980 gram carbon and 0.1302 gram water = 0.0145 gram hydrogen. 11. 0.530 gram substance gave 0.1780 gram Cr,O = 0.1222 gram chromium. 111. 0.485 gram substance gave 0-6128 gram silver chloride = 0.1516 gram chlorine. Found. 7 Calculated for /->--CloHl6,2CrO2CI,. I. 11. 111. Clo 120 26.84 P.C.26-42 p. C. - -B 1 6 . e . 16 3.58 3-90 ,, 2Cr . 105 25.49 , -202 . 64 14.32 , - - -- -25.05 p. C. -2C1,. . . 142 31.76 , - - 31.25 p. c. I _ -447 100.00 Pinene therefore like the other substances investigated by €hard, forms with chromium oxychloride a solid compound which has the formula ClJX1,,2CrO2Cl2. When thrown into cold water this is immediately decomposed with evolution of a considerable amount of heat and a heavy oil of a brown colour separates while the chromium sctlte go into solution. This oil was extracted by shaking up the solution with ether and the ethereal solution thoroughly washed, fir& with dilute caustic soda and finally with water dried with potassic carbonate and the ether then distilled off. In this way a transparent brown oil was obtained with a strong but pleasant aromatic odour.In order to purify it a portion of it was first shaken with a saturated solution of sodium bisulphite but no crystalline cornpound was formed. We then attempted to distil a part of it but found that it was entirely decomposed by heat ; heal y white fumes, with a suffocating and most disagreeable odour were given off and a black resinous mass was left in the flask. Another portion of the oil wa8 distilled with steam and although a considerable residue o CHROMIUM OXYCHLORIDE ON PINESE. 47 resinous matter was left in the retort a fair quantity of the oil was obtained now apparently pure. (In preparing a second supply of the oil after decomposing the solid chromium oxychloride compound with water we did not extract with ether &c.but simply passed sulphur dioxide through the solrition in order to reduce any chromic acid that might be present and then distilled off the oil with steam and dried it over potassic carbonate.) The oil was now golden-yellow in colour and perfectly transparent with the same pleasant odaur as. it had before distillation with steam. Its sp. gr. at 15' is 1.01366. Analysis of the oil gave the following results :-1. 0.1720 gram oil gave 0.4640 gram carbon dioxide = 0.1265 gram carbon and 0.1602 gram water = 0.0178 gram hydrogen. 11. 0.3075 gram oil gave 0.8298 gram carbon dioxide = 0.2263 gram carbon and 0.2830 gram water = 0.0315 gram hydrogen. 111. 0.2826 gram oil gave 0.0958 gram silver chloride = 0.0307 gram chlorine. Found.Calculated for --h- 7 C2oHuOC1. I. 11. 111. Cz0 . . 240 73.95 p. c. 7351 p. c. 75-59 p. c. -H 3 3 . . . 33 10.16 , 10.34 , 10.22 , -0 16 496 ,, C l . . . . 35.5 10.93 , - -- - -10.86 p. c . -424-5 100.00 The simplest formula that cau be given to the oil is therefore, C,H,,OCl. We were surprised to find chlorine in it having expected to obtain an oxy-compound possibly an aldehyde and we therefore heated the oil for fiome time with alcoholic potash but without alter-ing its composition to any appreciable extent. Several analyses of the oil were made both before and after distilling it with steam but the results were in each case very close to those given above. It seems possible that! the oil may be a mixture in equal proportions of CloHIaO and CloH,,CI but if this be so we were unable to separate i t into two fractions.As stated above it does not combine with sodic hydric sulphite. When heated with acetic chloride for some time its colour becomes slightly darker but i t is otherwise unchanged and it does not give any reaction either with hydroxylamine or phenyl-hydrazine ; it does not alter on exposure to the air. On attempting to distil the oil under ordinary atmospheric pressure, it is completely decomposed but this is not the case when it is distilled under diminished pressure ; the decomposition is then only partial. A smdl quantity OF resinous matter is left in the flask and an oil mixed with a little water comes over. The oil was dried and agai 48 MCMURTRY ON THTONYL THIOCYANATE. distilled under diminished pressure when it all came over between 180" and 185".In appearance this oil is very similar to the one pre-viously described ; its odour is almost the same and it behaves in the same way with alcoholic potash sodium hydrogen sulphite acetic chloride and phenylhydrazine ; its sp. gr. however is rather less being 0.97407 at 15" and its composition is quite different as is seen by the following analyses :-I. 0.2110 gram oil gave 0.6405 gram CO = 0.1648 gram C and 11. 0.2525 gram- oil gave 0.7225 gram CO = 0.1970 gram C and 0.1970 gram H20 = 0.0219 gram R. 0-2340 gram 320 = 0.0260 gram H. 111. 0.3705 gram oil gave 0.1697 gram AgC1 = 0.0420 gram C1. Found. Calculated for f- -7 C2oH31C1. I. 11. 111. C2". . . . 240.0 78.55 p. c. 78.13 p. c. 78.04 p.c. -HB . . . 51.0 10.11 , 10.37 , 10.29 , -C i . . . . 35.5 11-56 , - - 11-38 p. c. - -306.5 100.00 The simplest formula of this second oil is therefore C,oH,lCl and i t is formed from the first on distillation by loss of 1 mol. H20. C,oH,sOCl = C,oH,,Cl + HZO. This oil may also be a mixture of Cl0Hl6 and CloHl,C1 in equal pro-portions but we again failed to split it up into any fractions. We intend to prepare larger quantities of these oils in order to examine them more closely the results of our work being so different from what we expected