Influence of [H]-donating activity of hydrocarbons on transformations of thiophene compounds under catalytic cracking conditions

Abstract

Transformations of 2 methylthiophene and benzothiophene together with n undecane, declaim, or cumene under conditions of catalytic cracking have been studied. It has been found that enhancement of the [H] donating activity in the order cumene < n undecane < decalin leads to an increase in the degree of conversion of organic sulfur compounds, predominantly yielding hydrogen sulfide. An increase in the amount of 2 methylthiophene and benzothiophene alkylation and condensation products in the liquid prod ucts of cracking is observed in this case. Schemes of conversion of these compounds under catalytic cracking conditions have been proposed. The dependence of the degree of conversion of thiophene compounds into hydrogen sulfide on the ability of the catalyst to mediate hydrogen transfer reactions has been revealed.

Catalytic Removal of Sulfur Compounds From Petroleum Streams

“…Additives to FCC catalysts bring some advantages, such as octane number preservation; ease of operation; petroleum selection flexibility; hydrogen consumption reduction; and longer lifespan for post FCC desulfurization catalysts. Besides, its use can be advantageous for refineries, because it minimizes the need for additional costly structures, such as HDS (Potapenko et al, 2012;Siddiqui et al, 2006). A potential additive for gasoline sulfur removal is the Beta zeolite modified with metals, which allows greater adsorption of sulfurized compounds (Gong et al, 2009;Tian et al, 2012).…”

“…MgβI and MgβE catalysts presented lower selectivity to H 2 S values. There are several reaction mechanisms in the literature that propose different reactional paths for the observed compounds formation in Table 5 ( Jaimes et al, 2011;Potapenko et al, 2012). One can observe that catalytic cracking occurs by successive hydrogenations in the thiophene ring with the formation of hydro derivatives, and, finally, the production of H 2 S (Valla et al, 2006).…”