Removal of thiophenes from aromatic hydrocarbons by means of condensation in the presence of acid catalysts

The method of removal of thiophenes from aromatic hydrocarbons by means of condensation of thiophenes with formaldehyde catalyzed by different acids was investigated. Formic acid, acetic acid, Amberlyst-15, and H-β zeolite were used as the catalysts and their performances for thiophenes removal were compared. The aqueous formaldehyde and paraformaldehyde were used as the sources of formaldehyde. The results revealed that, under the catalysis of formic acid, the thiophenes can be converted to the compounds with higher boiling temperature efficiently and the formed products can be removed readily via fractional distillation without aromatic hydrocarbons losses. The effects of various operation conditions using formic acid as the catalyst were also studied. The condensation experiments were carried out to remove dibenzothiophenes from aromatic hydrocarbons and the results showed this method was not applicable to the elimination of dibenzothiophenes in aromatic hydrocarbons.