GB615624A - Process for the alkylation of aromatic hydrocarbons - Google Patents

Abstract

<PICT:0615624/III/1> An aluminium chloride-hydrocarbon complex catalyst formed by the interaction of aluminium chloride with an aliphatic olefine in the presence of hydrogen halide and having an aluminium chloride concentration of 60-85 per cent by weight of complex, is used in the alkylation of mononuclear aromatic hydrocarbons with an alkylating agent, e.g. ethylene or alkyl halides. The reaction may proceed at 0-120 DEG C. under sufficient pressure to maintain the hydrocarbon liquid and using 0.5-10 mol. per cent of hydrogen halide. As shown, hydrogen chloride, benzene, ethylene and preformed catalyst are charged to the alkylation reactor 6, provided with an agitator 7 and if desired cooling means, through the lines 60, 1, 62, and 56 respectively. The products pass to the settler 11 whence separated catalyst is recycled through line 68 to the reactor 6. Sufficient liquid catalyst is diverted through the cooler 50 and a vessel 53 containing granular aluminium chloride to maintain its AlCl3 concentration within the desired limits, while some catalyst may be removed at 71. Reaction products pass from settler 11 to columns 17, 23 and 29 which strip off hydrogen chloride, benzene and ethyl benzene respectively, the first two being recycled to the reactor 6 through the lines 43 and 38 and the ethyl benzene recovered. Polyalkylated benzene "bottoms" from column 29 withdrawn at 32 may be dealkylated with benzene and an alumina-silica catalyst to augment the ethylbenzene yield. The complex catalyst may be formed in situ in reactor 6. A substance furnishing hydrogen halide, e.g. an alkyl halide, may be used instead of hydrogen halide itself. The ratio benzene to ethylene may be 2-20 to 1 and preferably, 3-8 to 1. Specification 581,145, [Group IV], is referred to. The Specification as open to inspection under Sect. 91 discloses the alkylation of cyclic hydrocarbons in general. This subject-matter does not appear in the Specification as accepted.ALSO:<PICT:0615624/IV(b)/1> Mononuclear aromatic hydrocarbons are alkylated with an alkylating agent, e.g. ethylene or alkyl halides in the presence of an aluminium chloride-hydrocarbon complex catalyst formed by the interaction of aluminium chloride with an aliphatic olefine in the presence of hydrogen halide and having an aluminium chloride concentration of 60-85 per cent by weight of complex. The reaction may proceed at 0-120 DEG C. under sufficient pressure to maintain the hydrocarbon liquid and using 0.5-10 mol. per cent of hydrogen halide. As shown, hydrogen chloride, benzene, ethylene and preformed catalyst are changed to the alkylation reactor 6, provided with an agitator 7 and, if desired, cooling means, through the lines 60, 1, 62 and 56 respectively. The products pass to the settler 11 whence separated catalyst is recycled 68 to the reactor 6. Sufficient liquid catalyst is diverted through the cooler 50 and a vessel 53 containing granular aluminium chloride to maintain its AlCl3 concentration within the desired limits, while some catalyst may be removed at 71. Reaction products pass from settler 11 to columns 17, 23 and 29 which strip off hydrogen chloride, benzene and ethyl benzene respectively, the first two being recycled to the reactor 6 through the lines 43 and 38 and the ethyl benzene recovered. Polyalkylated benzene "bottoms" from column 29 withdrawn at 32 may be dealkylated with benzene and an alumina-silica catalyst to augment the ethyl benzene yield. The complex catalyst may be formed in situ in reactor 6. A substance furnishing hydrogen halide, e.g. an alkyl halide, may be used instead of hydrogen halide itself. The ratio benzene to ethylene may be 2-20 to 1 and preferably 3-8 to 1. Specification 581,145 is referred to. The Specification as open to inspection under Sect. 91 discloses the alkylation of cyclic hydrocarbons in general. This subject-matter does not appear in the Specification as accepted.