GB1325684A - Oligomerisation of olefins - Google Patents

Abstract

1325684 Olefin oligomerisation catalysts BP CHEMICALS Ltd 2 Nov 1970 [22 Dec 1969] 62237/69 Heading B1E [Also in Division C5] An olefin oligomerisation catalyst comprises elemental lithium or sodium dispersed on an anhydrous mixture of alkali metal carbonate and silver carbonate. The alkali metal carbonate may be a carbonate of potassium, rubidium or caesium. The catalyst, which may be in the form of powder, granules (chips or beads) or pellets, may contain from 0.1 to 25 parts by weight of lithium or sodium per 100 parts by weight of total carbonate; silver carbonate may constitute from 1.0 to 50.0 per cent by weight of the total carbonates. The catalyst may be prepared by a process (A) which comprises adding lithium or sodium metal to an anhydrous mixture of alkali metal carbonate and silver carbonate; alternatively, a catalyst comprising lithium may be prepared by a process (B) which comprises adding a solution of a hydrocarbyl lithium compound to an anhydrous mixture of potassium carbonate and silver carbonate and heating the resulting mixture to remove solvent and decompose the hydrocarbyl lithium compound or a catalyst comprising sodium may be prepared by a process (C) which comprises dissolving sodium metal in liquid ammonia, adding the resulting solution to an anhydrous mixture of alkali metal carbonate and silver carbonate, stirring the resulting mixture vigorously and allowing the liquid ammonia to evaporate from the resulting dispersion. The catalyst preferably is prepared in the presence of a blanket of an inert gas, for example nitrogen, helium or argon. As exemplified, catalyst is prepared under a blanket of argon either by process (B) from n-butyl lithium (in cyclohexane solvent) and a mixture of potassium carbonate and silver carbonate (Example I) or by process (A) from sodium and a mixture of caesium carbonate and silver carbonate (Example 2). Reference is made to Specification 1325683.