1207-12-1Relevant articles and documents
An efficient synthesis of pure 4,6-dimethyldibenzothiophene
Meille, Valerie,Schulz, Emmanuelle,Lemaire, Marc,Faure, Rene,Vrinat, Michel
, p. 3953 - 3960 (1996)
The synthesis of substituted dibenzothiophenes in the 4 and/or 6 positions has been optimized and pure 4,6-dimethyldibenzothiophene has been prepared by a new selective method; X-ray analysis of this compound is described.
Preparation of partially hydrogenated 4,6-dimethyldibenzothiophenes
Kukula, Pavel,Gramlich, Volker,Prins, Roel
, p. 1623 - 1640 (2006)
The synthesis of three key intermediates of the hydrogenation pathway in the hydrodesulfurization of 4,6-dimethyldibenzothiophene (4,6-DM-DBT; 1) is described. The hydrogenated derivatives 1,2,3,4-tetrahydro-4,6- dimethyldibenzothiophene (=4,6-dimethyl-1,2,3,4-tetrahydrodibenzothiophene; 4,6-DM-TH-DBT; 2), 1,2,3,4,4a,9b-hexahydro-4,6-dimethyldibenzothiophene (=4,6-dimethyl-1,2,3,4,4a,9b-hexahydrodibenzothiophene; 4,6-DM-HH-DBT; 3), and dodecahydro-4,6-dimethyldibenzothiophene (=4,6-dimethylperhydrodibenzothiophene; 4,6-DM-PH-DBT; 4) were prepared by direct hydrogenation of 1. The reactions were carried out in continuous and batch reactors by using metal sulfide as well as noble-metal catalysts. The influence of the reaction conditions on the formation of the products and the distribution of their stereoisomers was studied in detail. The isomers of the main products were isolated and characterized by NMR, GC/MS/MS, and X-ray crystal-structure diffractometry.
Hydrodesulfurization of 4,6-dimethyldibenzothiophene and its hydrogenated intermediates over bulk Ni2P
Yang, Lei,Li, Xiang,Wang, Anjie,Prins, Roel,Wang, Yao,Chen, Yongying,Duan, Xinping
, p. 144 - 152 (2014)
The hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene (4,6-DMDBT) and its hydrogenated intermediates 1,2,3,4-tetrahydro-4,6- dimethyldibenzothiophene (TH-4,6-DMDBT) and 1,2,3,4,4a,9b-hexahydro-4,6- dimethyldibenzothiophene (HH-4,6-DMDBT) over a bulk Ni2P catalyst was studied at 340 °C and 4.0 MPa in the presence and absence of piperidine. The rate constants of all steps in the network of the HDS of 4,6-DMDBT were measured. The HDS of 4,6-DMDBT occurred predominantly through the hydrogenation (HYD) pathway, and the HYD and direct desulfurization pathways were about equally inhibited by piperidine. Piperidine inhibited the desulfurization of TH-4,6-DMDBT and 4,6-DMDBT in the same way, but did not affect that of HH-4,6-DMDBT. In contrast to the HDS of TH-4,6-DMDBT over metal sulfide catalysts and to the HDS of TH-DBT, a fast dehydrogenation of TH-4,6-DMDBT to 4,6-DMDBT was observed. Besides 4,6-DMDBT, a small amount of the methyl-migration isomers was detected in the dehydrogenation product of TH-4,6-DMDBT, which is ascribed to the metallic character of Ni2P.
Hydrodesulfurization of dibenzothiophene, 4,6-dimethyldibenzothiophene, and their hydrogenated intermediates over bulk tungsten phosphide
Yang, Lei,Li, Xiang,Wang, Anjie,Prins, Roel,Chen, Yongying,Duan, Xinping
, p. 330 - 343 (2015/09/01)
The kinetics of the hydrodesulfurization (HDS) of dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT), and their hydrogenated intermediates over bulk tungsten phosphide (WP) was studied. WP possessed high hydrogenation/dehydrogenation activity but was highly sensitive to piperidine inhibition. 4,6-DMDBT reacted faster than DBT, and both DBT and 4,6-DMDBT reacted mainly through the hydrogenation pathway. The methyl groups suppressed the direct desulfurization of 4,6-DMDBT but significantly promoted the hydrogenation of 4,6-DMDBT and the dehydrogenation of 1,2,3,4-tetrahydro-4,6-dimethyldibenzothiophene (TH-4,6-DMDBT) and 1,2,3,4,4a,9b-hexahydro-4,6-dimethyldibenzothiophene, but decreased the rate of hydrogenation of TH-4,6-DMDBT. Piperidine inhibited the HDS of 4,6-DMDBT much more strongly than that of DBT. Substantial dehydrogenation of TH-4,6-DMDBT to 4,6-DMDBT and two of its isomers occurred. The formation of these 4,6-DMDBT isomers in the dehydrogenation of TH-4,6-DMDBT and the hydrocracking of 1-methyl-4-(3-methylcyclohexyl)-benzene, as well as the formation of cyclopentylphenylmethane and (cyclopentylmethyl)cyclohexane, is ascribed to the metallic character of WP.