69076-07-9

Upstream product

• 132-65-0 dibenzothiophene 
• 16587-33-0 1,2,3,4-tetrahydrodibenzothiophene 

Downstream Products

• 16587-33-0 1,2,3,4-tetrahydrodibenzothiophene 
• 92-51-3 cyclohexylcyclohexane 
• 827-52-1 1-phenyl-1-cyclohexane 
• 771-98-2 1-Phenylcyclohexene 
• 4410-78-0 (cyclopentylmethyl)benzene 
• 4431-89-4 (cyclopentylmethyl)cyclohexane 

Relevant academic research and scientific papers

Alkyldibenzothiophenes hydrodesulfurization-promoter effect, reactivity, and reaction mechanism

The promoter effect of Co or Ni on the HDS activity of sulfided Mo/alumina was studied using dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (46DMDBT) as reactants at 340°C under a 4 MPa total pressure in a fixed-bed microreactor. The promoted and unpromoted catalysts had different characteristics concerning the two main pathways, i.e., direct desulfurization and hydrogenation (HYD), of the HDS of DBT and 46DMDBT. The origin of differences in reactivity of these compounds to steric effects upon adsorption on the catalytic surface lay in the kinetics of transformation of these two compounds. The DDS and HYD pathways could be decomposed into H2 addition steps and C-S bond cleavage by elimination steps. The rate-determining step might be different depending on the reactant and on the catalyst. On the unpromoted catalyst, DBT and 46DMDBT had comparable reactivities because the C-S bond cleavages were rate-limiting for both reactants. On the promoted catalysts, DDS became the main pathway for the HDS of DBT. The HYD of DBT into dihydrodibenzothiophene was the rate-limiting step for the two pathways. With 46DMDBT, the influence of the promoter on C-S bond cleavage was limited due to steric constraints. Thus, C-S bond cleavage remained the rate-limiting step, particularly for the DDS pathway. The presence of the methyl groups in 46DMDBT changed significantly the reactivity concerning the two pathways. The low reactivity of 46DMDBT was due to the inhibition of the DDS pathway. Several explanations were proposed for this lower reactivity. The promoter improved the C-S bond cleavage activity of the MoS2 on alumina catalyst by increasing the basicity of certain sulfur anions shared between the Mo and the promoter, e.g., Ni or Co.

Influence of nanoscale distribution of Pd particles in the mesopores of MCM-41 on the catalytic performance of Pd/MCM-41

Two different nanoscale Pd particle distributions in MCM-41, i.e. in the mesopores and on the external surface, were obtained by using a siliceous MCM-41 and a silylated MCM-41 (S-MCM-41) as the starting support materials, respectively. The electron density of Pd in Pd/S-MCM-41 was lower than that in Pd/MCM-41. Pd/S-MCM-41 exhibited much better selective hydrogenation performance but a lower hydrogenolysis activity than Pd/MCM-41. These differences are related to the different Pd particle distributions in MCM-41 and S-MCM-41, demonstrating that the performance of noble metal catalysts is tunable by simply controlling the nanoscale metal particle distribution in the pores.

The preparation of Mo/γ-Al2O3 catalysts with controllable size and morphology via adjusting the metal-support interaction and their hydrodesulfurization performance

In this work, a series of Mo/γ-Al2O3 catalysts have been prepared by using Mo species enwrapping with dodecyltrimethylammonium bromide (DTAB) as the novel precursors for the hydrodesulfurization (HDS) of dibenzothiophene (DBT). The objective of this work is to get a deep insight into the effect of the Mo precursors on the size and morphology of the active phases and HDS activity. DTAB as the organic additive for the preparation of Mo precursors can dominate the nature of precursor solution and adjust the metal-support interaction so as to control the dispersion and morphology of the active phases. It is clearly shown that the addition of DTAB can effectively decrease the strong interaction between the Mo species and γ-Al2O3 support and favor to tune the size and morphology of MoS2 nanoparticles. The optimum molar ratio of DTAB/Mo is 3/5 and the corresponding catalyst shows the highest sulfidation degree with the most suitable stacking layer numbers and the shortest length of MoS2 and thus exhibits the best HDS performance. Our work explores the important roles of organic additive to adjust the metal-support interaction and control the morphology of active phases and provides an effective precursor which can be used widely to prepare supported catalysts.

Hydrodesulfurization of dibenzothiophene, 4,6-dimethyldibenzothiophene, and their hydrogenated intermediates over bulk tungsten phosphide

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.

Desulfurization of diesel fuel with nickel boride in situ generated in an ionic liquid

In order to improve the desulfurization efficiency, an ionic liquid (IL) was used as the solvent for the desulfurization of diesel fuel with nickel boride. The nickel boride prepared in IL-H2O showed high specific surface area. The desulfurization efficiency of model organosulfur compounds in this work was higher than that in the previous studies. The desulfurization reactivity of model organosulfur compounds followed the order of BT (DBT) > 3-MBT > 4,6-DMDBT. Furthermore, the products of model organosulfur compounds after desulfurization were analyzed by GC/MS and their corresponding reaction routes were proposed. The effectiveness of nickel salts followed the order of NiCl2 (Ni(OAc)2) > NiSO4 > Ni(NO 3)2. The desulfurization efficiency of model diesel fuels reached 90.6% under the conditions of B/S molar ratio = 9, Ni(OAc)2/S molar ratio = 3, oil/IL volume ratio = 3, water content in IL = 5%, and reaction time = 50 min. ILs maintained their original structures after regeneration. Finally, the desulfurization of real diesel fuel was carried out and a desulfurization efficiency of 88.6% was obtained in 50 min. This journal is the Partner Organisations 2014.

Hydrodesulfurization of dibenzothiophene, 4,6-dimethyldibenzothiophene, and their hydrogenated intermediates over Ni-MoS2/γ-Al2O3

The rate constants of all reaction steps in the hydrodesulfurization (HDS) of dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (DMDBT), and their tetra- and hexahydro intermediates TH(DM)DBT and HH(DM)DBT over Ni-MoS2/γ-Al2O

Hydrodesulfurization of dibenzothiophene and its hydrogenated intermediates over sulfided Mo/γ-Al2O3

Two intermediates of dibenzothiophene (DBT)-tetrahydro-DBT (THDBT) and hexahydro-DBT (HHDBT)-were synthesized, and their hydrodesulfurization (HDS) mechanism was investigated over Mo/γ-Al2O3 at 300-340 °C and 5 MPa in the absence and presence of H2S and 2-methylpiperidine. The rate constants of all steps in the kinetic network of the HDS of DBT were measured. THDBT underwent desulfurization by hydrogenolysis to 1-phenylcyclohexene, followed by hydrogenation to phenylcyclohexane. The desulfurization of HHDBT occurred by hydrogenolysis of the aryl C{single bond}S bond and then cleavage of the cycloalkyl C{single bond}S bond of the resulting thiol by elimination to 1-phenylcyclohexene and by hydrogenolysis to phenylcyclohexane. H2S strongly inhibited the desulfurization of all three molecules but did not inhibit (de)hydrogenation. 2-Methylpiperidine also had a strong inhibitory effect, especially on (de)hydrogenation and, to a lesser extent, on desulfurization. The order of the inhibition of DBT, THDBT, and HHDBT was explained by the adsorption constants of these three molecules.

Molecular rearrangement in the Birch reduction of dibenzothiophenes

A molecular rearrangement observed during the Birch reduction of dibenzothiophene and 4,6-dimethyl-dibenzothiophene was explored and a mechanism for the rearrangement has been proposed.

XPS study of the deactivation and sulfiding of nitrided molybdena-alumina catalyst during the hydrodesulfurization of dibenzothiophene

The deactivation and sulfidation processes of nitrided 12.5% Mo/Al2O3 catalysts at the initial stage were studied on the basis of the behavior of sulfur and nitrogen using XPS spectroscopy. The hydrodesulfurization (HDS) of dibenzothiophene was carried out in a fixed-bed microreactor at 573 K and 10.1 MPa of total pressure. The Mo/Al2O3 catalyst was nitrided by a temperature-programmed reaction with pure ammonia at 4 L h-1 at various temperatures. From XPS measurement, the sulfur atoms removed from dibenzothiophene were not exchanged with nitrogen atoms in the nitride catalyst during the first hour but molybdenum was sulfided by 71% of the total sulfur accumulated during the 14-h run. The sulfur deposition followed the Elovich equation. The decreased HDS activity and increased hydrogenation selectivity of the nitride Mo/ Al2O3 catalyst were caused by the accumulation of sulfur on the nitride catalyst. At steady state achieved after 14 h, however, the nitrogen achieved after the Mo/Al2O3 catalysts were nitrided at high temperatures was difficult to exchange by deposition of sulfur and the release of nitrogen from the nitride catalyst was hampered. The regeneration of the aged nitride catalysts with NH3 after the 14 h-run increased the activity and decreased the hydrogenation selectivity. The mechanism of the regeneration of the aged nitride catalyst by NH3 retreatment and the exchange of oxygen or nitrogen atoms with sulfur atoms in the HDS of dibenzothiophene on the nitrided Mo/Al2O3 catalyst are also discussed.

Hydrodesulfurization of Alkyldibenzothiophenes over a NiMo/Al2O3 Catalyst: Kinetics and Mechanism

The transformation mechanism of dibenzothiophene, 4-methyldibenzothiophene, 4,6-dimethyldibenzothiophene, and 2,8-dimethyldibenzothiophene has been studied in a batch reactor over an industrial NiMo/Al2O3 hydrotreating catalyst at 573 K under 5 MPa of hydrogen pressure. A detailed mechanistic study including competitive catalytic experiments proved that the adsorption of the most refractory molecules at the catalyst surface was not the rate-determining step for their transformation. Our results imply that the hydrodesulfurization of these compounds occurs on one single type of sites by a flat adsorption, leading to a preliminary partial hydrogenation of one aromatic ring. Variations in reactivities of the dibenzothiophene derivatives were thus explained by different reaction rates for the C-S bond scission due to steric hindrance generated by the methyl substitution near the sulfur atom.