Disproportionation of Mixtures of C₄ Olefins over Tungsten Oxide-Silica Catalyst

Abstract

Disproportionation of the equimolar mixtures of two C4 olefins has been investigated over a WO^3-SiO₂ catalyst at a total pressure of about 1 atm and at 450° C in a quartz reactor. The ratios of the initial rate of each primary metathesis were determined: in the reaction of 1- butene with isobutylene, r1B-1B:r1B-tB:riB-iB=90:50:1, in the reaction of cis-2-butene with isobutylene, rcB-tB:riB-1B=100:1, and in the reaction of trans-2-butene with isobutylene, riB-1D:r1B-tB=120:1. In the reactions of 1-butene with cis-2-butene and 1-butene with trans-2-butene, the ratios of initial rates were r1B-1B:r1B-CB=1B-1B:r1B-iB=1:6.
Under the conditions of these experiments, the disproportionation was accompanied with the migration of double bonds, which affected the distributions of products considerably. As shown in Fig.8, the linear velocity of feed affected the rate of disproportionation but did not change the rate of isomerization. The higher linear velocity was preferable to the selective dispro- portionation. In the reaction of 2-butenes with isobutylene, high selectivity to isoamylenes was attained when the concentration of isobutylene in the feed was considerably high.