STUDY OF THE REGULARITIES OF TETRAHYDROFURAN RECYCLING INTO THIOLAN OVER SOLID ACID CATALYSTS

The heterogeneous reaction of tetrahydrofuran with H2S was studied in the presence of catalysts containing acid sites on the surfaces. Proto n-donor catalysts exhibit low selectivity and stability, because they induce decomposition and polymerization of tetrahydrofuran. Alumina ca talysts containing strong Lewis acid sites and basic sites of moderate strength are more effective. According to the postulated mechanism, u pon interaction of tetrahydrofuran with an acid site, an oxonium compl ex is formed that decomposes with the formation of alkoxy and hydrocar bon structures. Thiolan is formed as a result of the reaction of alkox y structures with hydrogen sulfide, which is either present in molecul ar form, or is dissociatively chemisorbed on the catalyst surface.