process for regenerating a spent solid catalyst from the disproportionierung of alkenes and its use

摘要

1494619 Disproportionating alkenes SHELL INTERNATIONAL RESEARCH MAATSCHAPPIJ BV 16 Dec 1974 [18 Dec 1973] 58480/73 Heading C5E [Also in Division B1] In a process for the disproportionation of alkenes the solid catalyst is regenerated by contact at elevated temperature with an alkene material which is different from both the feedstock for and the product of the disproportionation and which comprises one or more alkenes of at most 12C and, after part of the deposited organic material on the catalyst has been removed thereby, treatment with an oxygen-containing gas at a temperature below 650‹ C. to remove substantially all of the remaining deposited organic material thereform. The catalyst may be contacted with an inert gas after the contact with the regenerating olefin and before the treatment with the oxygen-containing gas. The preferred catalysts comprise molybdenum and cobalt oxides on alumina but tungsten oxide on silica or alumina or rhenium heptoxide on alumina may also be used. The contact with olefin is preferably a washing at 75-250‹ C. The feedstock for the disproportionation may comprise predominantly normal internal alkenes which may be mixtures of C 6 -C 10 and C 18 -C 40 alkenes obtained by oligomerization of ethylene, separation of the C 12 -C 16 alkenes by distillation and double bond isomerization of the remaining alkenes. The feedstock may also comprise alkenes obtained by isomerizing alpha-alkenes with the aid of an isomerization catalyst disposed in three fixed beds connected in series and operated so that as each bed is exhausted it is disconnected while the catalyst is replaced by fresh catalyst and then reconnected as the last bed in the series when the conversion in the remaining two beds has fallen to a predetermined level.