Catalytic reactions of n-propanol and n-butanol with hydrogen sulfide

Abstract

The transformations of n-propanol and n-butanol in an H2S atmosphere at T = 300–350°C and P = 0.1 MPa in the presence of acid–base catalysts were studied. Only alcohol dehydration with the release of alkenes occurred at a high rate on catalysts with strong proton sites (tungstosilicic and tungstophosphoric acids on SiO2 or a decationized high-silica zeolite), whereas alcohol thiolation with the formation of alkanethiols also occurred on catalysts with Lewis acid sites (Al2O3; NaX; MgO; Cr/SiO2; and Al2O3 modified with W, K, Na, K2WO4, or Na2WO4). The rate of reaction decreased with decreasing strength of Lewis acid sites and with increasing strength of basic sites; however, the selectivity of thiol formation increased. Alumina modified with alkaline additives was the most selective catalyst. In the presence of this catalyst, an alcohol selectively reacted with H2S to form an alkanethiol, and the alkanethiol underwent partial decomposition with the release of an alkene and H2S at a long contact time.