A method for the production of 4 - chlorine - 3 - methyl - a ≠ - methylstyrene and 3 - chlorine - 4 - methyl - a ≠ - methylstyrene

摘要

A product consisting substantially of 4-chloro-3-methyl-a -methylstyrene which may contain varying amounts of 3-chloro-4-methyl-a -methylstyrene is prepared by isopropylating o - chlorotoluene with propylene, isopropyl chloride, isopropyl alcohol, or a mixture of the first two of these in presence of an acidic catalyst, and then dehydrogenating the resultant isopropylbenzene. The proportion of 3-chloromethyl-isopropylbenzene formed increases with reaction temperature and the quantity of catalyst used in the alkylation reaction. An example is given of the process; the dehydrogenation is done catalytically in the vapour phase. Specifications 510,450 and 687,265, [Group IV (a)], are referred to.