CATALYTICALLY DEHYDROGENATING ALKYLATED AROMATIC HYDROCARBONS

1295776 Alkenyl aromatics BADISCHE ANILIN- & SODA-FABRIK AG 2 April 1970 [3 April 1969] 15624/70 Heading C5E Alkenyl aromatics are obtained by catalytic dehydrogenation of corresponding alkyl aromatics by (a) preheating the feedstock, optionally mixed with steam and/or alkenyl aromatic, to 400-620‹ C., (b) heating steam to 820-1100‹ C., (c) mixing the preheated feedstock and the heated steam to provide a blend at a temperature of 550-700‹ C., the mixing time being less than 0À1 second, and (d) passing the mixture to a catalyst zone, the residence time from the mixing point to the point of entry into the catalyst zone being less than 0À2 second. Preferably there are several catalyst zones arranged in series, with reheating between each zone by admixing further steam heated to a temperature above reaction temperature and/or by applying heat indirectly. The catalyst beds may be fixed or fluidized, and the catalyst may comprise any of the following mixtures:- iron oxide / chromium oxide / potassium oxide; iron oxide / zinc oxide / potassium oxide; alumina / zinc oxide / magnesia; iron oxide / zinc oxide / vanadium oxide / alkali metal chromate; zinc oxide / alumina / calcium oxide / magnesia / alkali metal oxide; and chromiumfree iron catalysts. Suitable feeds include isopropyl benzene, diethyl benzene, ethyl naphthalene, and particularly ethyl benzene.