Synthesis of s-Butyltoluene by the Gas Phase Alkylation Reaction of Toluene with 1-Butene Using γ-Alumina-Boria Catalyst

Abstract

For a selective synthesis of s-P-butyltoluene by an alkylation reaction of toluene with 1-betene, optimal reactioni conditions and suitable catalysts have been found by the authors.In this paper, the experimental results ofthe reaction in gas phase with the alumina boria catalysts using r-alumina as a base are reported. The conclusions may be summarized as follows:1) r-aluminareacted with boric gcid to form strongly acidic centers, as well as with tyand X-alumina, developing activity of toluene alkylation. The total acid amount of the catalyst was distributed uniformly over the acid centers with acid strength Hg ranging from +7.1 to -8.2. The catalysts containing O -vlO wt% boria had much more weak acid centers and Lewis acid ones than those containing more than 15 wt% boria. At the boria contents more than 15 wt% the greater parts of the acid centers were strong acids, considered as Bronsted type, and the acid amount showeda maximum at 15 wt 9Zer boria and this maximum value increased with inCreasing calcina temperature Qf the catalyst, 2) The activity was attributed to the acid centers at strength H, ;-3.0, being directly proportional to its acid amount, When the reaction proceeded with sIight decrease in activity as a result of co:keformation, as may be seen from the above fact and the result shown in 1), the catalyst containing about 15 wt%boria showed the maximum activity that became higher as the calcination temperature increased.3) At transient-state activity(about an hour after the start of run), the toluene conversions and s-butylto1uene(SBT)yields increased as the reaction temperature increased. While at stationary-state activity(five hours after the star of run)they decreased with increasing reac on temperature because of a cataryst decay. Alsg the isomer distribution of SBT at stationary-state activity was slightly dependent on reaction, condition, s, but independent of preparing conditions of the catalyst, and the SBT contained approxi:matly 20% of o-and m-isomer and 60% of p-one.