Alkylation desulfurization of the C9 fraction over Amberlyst 36 resin

The C-9 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 C-9 fractions is getting higher. As a result, the C-9 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, 2ethyl-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 C-9 fraction was measured. It was found that the conversions of the thiophenic compounds could reach above 99%, and the octane number of the C-9 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.