Production of 4-vinylcyclohexene as a precursor for styrene and ethylbenzene involves dehydrogenation of a feed gas containing n-butane followed by cyclodimerization of the resulting butadiene

摘要

A method for the production of 4-vinylcyclohexene involves dehydrogenation of a feed gas containing n-butane followed by cyclodimerization of the resulting butadiene. A method for the production of 4-vinyl-cyclohexene (VCH) involves: (A) preparation of a feed gas stream containing n-butane; (B) dehydrogenation of the n-butane to give a product stream containing butadiene, n-butane, possibly 1- and 2-butene and possibly water vapor and other components; (C) catalytic dimerization of butadiene in the product stream to give a product stream containing VCH, n-butane and possibly 1-butene, 2-butene and unreacted butadiene; and (D) separation of VCH, with recycling of n-butane etc. to stage (B). Independent claims are also included for: (1) a method (M1) for the production of ethylbenzene (EB) or styrene (S), involving stages (A-D) as above followed by (E) catalytic dehydrogenation of VCH to EB or oxidative dehydrogenation in presence of oxygen to give S; (2) a method (M2) for the production of styrene (S) by (B') feeding a n-butane-containing stream and a VCH-containing stream into a dehydrogenator and dehydrogenating the mixture in presence of oxygen to give a mixture of styrene (S), butadiene, n-butane, 1- and 2-butenes and possibly EB etc., (C') separating the S, EB and other high-boiling by-products, (D') dimerizing the butadiene/butane/butene-containing stream to give a stream containing VCH, butane and butenes etc., (E') separating VCH from this stream and passing it to the dehydrogenator.