C a t a l y t i c R e a c t i o n s at High Temperatures and Pressures. XXII. D e c o m p o s i t i o n of Hexane and cycZoHexane ; I s o m e r i s ation of cpcZoHexane. WLADIMIR N. IPATIEFF and N. DOWGELEWITSCH ( Bey., 191 1,44, 21387--2992).-At ordinary pressures, hexme and cyclohexnne are decomposed when passed through a n iron tube at 650-700', the decomposition being accelerated by the presence of alumina ; hexane decomposes more readily than cpclohexane. The gases thereby produced consist

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... of saturated hydrocarbons, hydrogen, ethylene, propylene, and probably isobutylene, whilst the liquid polymerisation product contains a very small proportion of unsaturated hydrocarbons. No hydrocarbons were obtained which reacted with a nitrating mixture or with permanganate. The course of reaction is quite different under high pressures, taking place at a much lower temperature. With hexane, at 510°, the increase in pressure takes place so rapidly t h a t an explosion occurs, so that cyclohexane only was used in these experiments. It was heated for four hours at 500-510" in the presence of alumina, a t a pressure of 110-120 atmospheres ; no reaction takes place at this temperature in the absence of alumina. After removal of the ethylene hydrocarbons from the liquid polymerisation product by means of sulphuric acid, the remaining liquid was divided into eleven fractions, none of which decolorised permanganate. The first three fractions, 45-80', contained polymethylene hydrocarbons, among which was methyl cyclopentane, but no saturated hydrocarbons. The fractions Vl-XI, 125-280", reacted with a nitrating mixture, and therefore contained benzene hydrocarbons ; nitro-compounds were also obtained from fractions V I (125-150') and VII (150-170').