Hydrodesulfurization of Dibenzothiophene Catalyzed by Supported Metal Carbonyls(Part 3). Effects of Supports on Catalysts Prepared from Supported Anionic Molybdenum Carbonyls.

Abstract

In hydrodesulfurization (HDS) of dibenzothiophene (DBT) catalyzed by a supported anionic molybdenum carbonyl, [NEt4][Mo(CO)5(CH3COO)]/support (Et=ethyl group), the effects of supports (SiO2-Al2O3, Al2O3, SiO2, TiO2, NaY zeolite, HY zeolite HZSM-5, and active carbon) on catalytic activity and product selectivity were investigated in a pressurized flow reactor. The yields of hydrodesulfurization products, biphenyl (BP), cyclohexylbenzene (CHB), and bicyclohexyl (BCH) decreased in the order, SiO2-Al2O3>Al2O3>TiO2=Active carbon>SiO2>NaY zeolite=HZSM-5>HY zeolite. The rates of HDS per amount of molybdenum loaded decreased in the order, SiO2-Al2O3>TiO2>NaY zeolite>Al2O3>SiO2. When HY zeolite was used, hydrocracking occurred significantly and BP, CHB, and BCH were not produced. When active carbon was used, a substantial amount of DBT was adsorbed on it, and the material balance could not be completely obtained.From NO chemisorption and XPS measurement of the catalysts derived from silica-alumina supported anionic molybdenum carbonyls, it was deduced that presulfidation of [NEt4][Mo(CO)5(CH3COO)]/SiO2-Al2O3 and Mo(CO)6-triethylamine(NEt3)-ethanethiol(EtSH)/SiO2-Al2O3 systems would give a silica-alumina supported MoS2-x species which was active in HDS of DBT.

Novel hydrodesulfurization catalysts derived from a rhodium carbonyl complex

“…Our group have not only studied HDS of DBT over conventional molybdenum-alumina systems [15][16][17] but also over alumina-supported metal carbonyl complexes (Mo(CO) 6 , Cr(CO) 6 , W(CO) 6 ) [18], alumina-supported anionic ruthenium carbonyls [19,20], alumina and silica-alumina supported molybdenum and cobalt carbonyls [21], and alumina-supported ruthenium carbonyl-alkali metal hydroxides [22]. We have also studied the effect of the support on HDS activities of catalysts prepared from supported anionic molybdenum carbonyls [23] and of catalysts prepared from supported ruthenium carbonyl-cesium hydroxide systems [24]. The main results of these studies can be summarized as follows:…”