A Probable Origin of Dibenzothiophenes in Coals and Oils

To probe the possibility of thiophenolate as an origin of dibenzothiophenes (DBTs) and establish the detailed chemical transformations from thiophenolate to DBTs, the thermal degradation of thiophenolate has been carried out at various temperatures. The characterizations of both gaseous products and solid residues indicate that DBTs together with benzene, diphenyl sulfide, and diphenyl disulfide are the major degradation products. The presence of benzene supports that the thermal degradation of thiophenolate begins with the homolysis of Ar‒H bonds. The subsequent hydroarylation followed by the elimination and cyclization reactions facilely generates DBTs. The transformation of thiophenolate to DBTs is chemically simple and highly geochemically feasible. It readily unifies the chemical pathways involved in the generation of DBTs from thiophenolate and that of dibenzofurans from phenolate in nature.

Synthesis of diphenyl sulfide from iodobenzene and thiophenol using Metal-Organic Framework Cu2(NDC)2(DABCO) as an efficient heterogeneous catalyst

A metal-organic framework Cu2(NDC)2(DABCO) was synthesized from copper nitrate trihydrate, 2,6-Napthalenedicarboxylic acid (H2NDC), and 1,4-diazabicyclo[2.2.2]octane (DABCO) by solvothermal method. Its physicochemical properties were confirmed by several techniques such as X-ray powder diffraction (PXRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Cu2(NDC)2(DABCO) appeared as well-shaped crystals. To get diphenyl sulfide as desired product from the C-S cross coupling reaction of iodobenzene and thiophenol, the Cu2(NDC)2(DABCO) was used as heterogeneous catalyst in the presence of LiO-tBu as base. The results showed that the transformation could proceed with more than 93% reaction conversion being obtained after 6 h at 120 oC when using 5 mol% Cu2(NDC)2(DABCO) catalyst in the presence of LiO-tBu. The solid catalyst could be recovered and reused five times without a significant degradation in catalytic activity. The coupling reaction could only proceed to achieve major product in the presence of the Cu2(NDC)2(DABCO catalyst.