ALKYLATION OF ISOBUTANE WITH PENTENES USING SULFURIC-ACID AS A CATALYST - CHEMISTRY AND REACTION-MECHANISMS

Isobutane was alkylated either with a pure C5 olefin, with a mixture of a pure C5 olefin and mixed C4 olefins, with C4 olefins, or with propylene using sulfuric acid as the catalyst. Alkylates produced at operating conditions of commercial importance had research octane numbers of 90.7-91.7, 97.8, 93.2, and 89.0, respectively, when C5 olefins, n-butenes, isobutylene, and propylene were used as olefins. The compositions of the alkylates produced from n-pentenes, and especially 2-pentenes, were significantly different than those of alkylates produced from isopentenes. Cyclopentene which is present in C5 mixtures of refinery products produces very poor quality alkylates in low yields. For both n-pentenes and isopentenes, isopentane is produced by self-alkylation in appreciable amounts. The alkylation chemistry differs significantly for various C5 olefins, and reaction mechanisms are proposed and compared to those for C3 and C4 olefins.