Bp Chemicals Limited

James Mann Scotland

John McMahon

James Maxwell Kerr

Robert G Laverick

This invention relates to a method of producing polyisobutenes from a feedstock comprising a mixture of C4 hydrocarbons and containing isobutene and at least 5% by weight of 1-butene using a cationic polymerisation catalyst, characterised in that prior to polymerisation, the feedstock is subjected to a pre-treatment step in order to reduce the 1-butene content thereof to a level which is at least 20% lower than that of the 1-butene content in the initial mixed C4 hydrocarbon feedstock prior to the pre-treatment thereof and the polyisobutene so formed is (a) very high in its vinylidene group content and (b) substantially free of halogen.

Production of polyisobutenes

Pure acetone is recovered from a crude acetone vapor fraction removed overhead from a first column separating phenol and higher boilers as a bottom fraction from a cumene hydroperoxide cleavage reaction product by partially condensing the crude acetone fraction, returning the condensed portion of the crude acetone fraction to the first column as reflux, feeding the remaining portion as a vapor to an intermediate point in a second distillation column to which there is also fed continuously at a point above the acetone feedpoint a dilute aqueous solution of an alkali, removing from the base of the second column a residue fraction comprising compounds boiling above acetone, removing from a point in the second column intermediate; between the alkali feedpoint and the top of the column as a liquid sidedraw fraction pure acetone having a permanganate time (PT) greater than 4 hours, and removing from the top of the second column as a vapor fraction acetone having a PT less than that of the sidedraw fraction, condensing the acetone vapor fraction and returning to the second column at a point above the liquid acetone sidedraw removal point a portion of the condensate as reflux.

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Stirlingshire, United Kingdom

James Mann Scotland