Alkylation desulfurization of the C9 fraction over Amberlyst 36 resin

Abstract

The C₉ fraction is the by-product of catalytic reforming and in ethylene crackers, and is usually considered as a kind of petroleum resin raw material. Recently, it was studied for use as a gasoline additive to enhance economic benefits. However, the sulfur content of C₉ fractions is getting higher. As a result, the C₉ fraction alkylation desulfurization process, which consists of weighing down the sulfuric compounds by catalytic alkylation with olefins present in the feed, followed by distillation, has become attractive. In this paper, 2-ethyl-5-methylthiophene, 2,5-dimethylthiophene and 2-n-propylthiophene were selected as model compounds. Firstly, the alkylation reaction of the thiophenic compounds with vinyltoluene was researched over a macroporous sulfonic resin, Amberlyst 36. Then, the octane number of the C₉ fraction was measured. It was found that the conversions of the thiophenic compounds could reach above 99%, and the octane number of the C₉ fraction was increased. Moreover, the alkylation of thiophenic sulfur could be described as a pseudo-first-order reaction, and the rate constant and activation energy of the alkylation reactions were also calculated.