Thiophenes catalytic hydrodesulfurization

Here we illustrate how to use kinetic data to establish a power rate law, and how to derive rate constants, equilibrium constants of adsorption and even heats of adsorption when a kinetic model is available. We use the catalytic hydrodesulfurization of thiophene over a sulfidic nickel-promoted M0S2 catalyst as an example ... 

Hydrodesulfurization of certain hydroxy-437 and methoxy-sub-stituted615 alkybenzo[6]thiophenes is a useful means of preparing some otherwise inaccessible alkyl-substituted phenols [e.g., Eq. (15)].015 Various p-methoxyphenylbenzo[6]thiophenes have been employed similarly to prepare the corresponding hydroxydiphenyl-alkanes.464 Catalytic hydrodesulfurization of a-alkyl-/ -(3-benzo[6]-thienyl)propionic acids affords a convenient method of preparing a,y-disubstituted y-phenylbutyric acids.636 Treatment of / -(3-benzo[6]thienyl)acrylic acid with Raney nickel alloy, sodium meth-oxide, and deuterium oxide affords the deuterated acid (366).667... 

Catalytic hydrodesulfurization (HDS) is a very important industrial process that involves removal of sulfur from crude oils by high-temperature ( 400°C) treatment with hydrogen over Co- or Ni-promoted Mo or W catalysts supported on alumina. In an attempt to determine the mechanism of this process, many transition metal complexes of thiophene, a sulfur-containing heterocycle that is particularly difficult to desulfurize, have been prepared and their reactivities studied in order to compare their behavior with those of the free thiophenes that give H2S and C4 hydrocarbons under HDS conditions (88ACR387). Thiophene can conceivably bind to the catalyst surface by either cr-donation via a sulfur electron pair or through a variety of -coordination modes involving the aromatic system... 

Several excellent reviews of the early work on thiophene reduction are available. The present discussion will not cover the important industrial topic of catalytic hydrodesulfurization of thiophenes in petroleum. ... 

Satterfield, C.N., M. Modell and J.R. Mayer. "Interaction between Catalytic Hydrodesulfurization of Thiophene and Hydrode-nitrogenation of Pyridine." AIChE J. (6) (1975) 1100. 

Desikan, P. and C.H. Amberg. "Catalytic Hydrodesulfurization of Thiophene. V. The Hydrothiophenes, Selective Poisoning and Acidity of Catalyst Surface." Can. J. Chem. 42 (1964) 843. 

Satterfield, C.N., Modell, M., and Mayer, J.F. (1975) Interactions between catalytic hydrodesulfurization of thiophene and hydrodeni-trogenation of pyridine. AIChE J., 21,1100. 

The reaction of thiophenes and other related sulfur heterocycles with low-valent metal fragments has importance in relation to the catalytic hydrodesulfurization (HDS) process (see Section 8.02.4.1). Oxidative addition of halogenated thiophenes can involve C-S bond cleavage (Equation (40)) or oxidative addition of the G-X bond... 

Senevirathne K, Bums AW, Bussell ME, Brock SL (2007) Synthesis and characterization of discrete nickel phosphide nanoparticles effect of surface ligation chemistry on catalytic hydrodesulfurization of thiophene. Adv Funct Mater 17 3933-3939... 

The studies of ammonia synthesis over Fe and Re and the hydrodesulfurization of thiophene over Mo, described above, illustrate the importance and success of our approach of studying catalysis over single crystal samples at high pressures. The use of surfaces having a variety of orientations allows the study of reactions that are surface structure sensitive 6Uid provides insight into the nature of the catalytic site. Here we have shown that the ammonia synthesis... 

Smectite-type materials containing transition metal divalent cations (Ni2+, Co2, and Zn2+) in octahedral sheets were synthesized. The synthetic smectites were thermally stable and had large surface areas and high pore volumes after evacuation at 873 K. Catalytic activities of synthetic smectites were investigated. The Ni2 -containing smectites were active for the isomerization of 1-butene and the oligomerization of ethylene. The Co2+-containing smectites were active for the hydrodesulfurization of thiophene. 

OATS [Olefinic Alkylation of Thiophenic Sulfur] A gasoline desulfurization process. Thiophenes and mercaptans are catalytically reacted with olefins to produce higher-boiling compounds that can more easily be removed by distillation prior to hydrodesulfurization. This minimizes hydrogen usage. The process uses a solid acid catalyst in a liquid-phase, fixed bed reactor. Developed by BPAmoco in 2000 and tested in Bavaria and Texas. First used commercially at the Bayernoil refinery, Neustadt, in 2001. The process won a European Environment Award in 2002. 

M. Arai, Y. Wada, and Y. Nishiyama, Thiophene hydrodesulfurization by catalytic palladium membrane systems, Sekiyu Cakkaishi 36 44 (1993). 

Cr- FILM from the different cationic forms of this clay [4], These materials exhibited dehydration and dehydrogenation activity in the decomposition of 2-propanol and ethanol. Cr-PILM catalysts activated by HjS/Hj mixture displayed also an interestingly high activity for thiophene hydrodesulfurization (HDS). Now, the Cr-PILM s have been prepared form different clays with the objective to obtain new porous materials with potential catalytic applicability. Their physicochemical properties and the catalytic behaviour for thiophene HDS have been investigated. 

Pt/HZSM-5 showed high and stable catalytic activity for the hydrodesulfurization of thiophene at 400 C and its catalytic activity was higher than that of commercial C0M0/AI2O3 catalyst. It is concluded that the Brdnsted acid site and spillover hydrogen formed on Pt particle in Pt/HZSM-5 catalyst play an important role for the hydrodesulfurization of thiophene. 

In the present work, the catalytic activity of noble metals (R, Rh, Pd, Ru) supported on NaZSM-5 and HZSM-5 zeolites were studied in the hydrodesulfurization of thiophene in order to develop more highly active... 

The catalytic activity of various noble metals supported on NaZSM-5 and HZSM-5 zeolites was examined in the hydrodesulfurization of thiophene at 400 C (Figure 1). The activity was markedly changed by the the kind of noble metal and the order of the catalytic activities of noble metal/NaZSM-5 catalysts was as follows ... 

Rgure 2 shows the hydrodesulfurization of thiophene over various noble metal/HZSM-5 catalysts. It was found that the order of the catalytic activities of noble metal/HZSM-5 corresponded to that found with NaZSM-5 preparations. Pt/HZSM-5 catalyst showed stable activity. This activity was the highest, even higher than the activity of the C0M0/AI2O3 catalyst. The reaction products in the hydrodesulfurization of thiophene over noble metalsM-5 catalysts were hydrogen sulfide and C1-C4 hydrocarbons. 

Noble metals supported on HZSM-5 zeolite show higher catalytic activity than on NaZSM-5, suggesting that the Brbnsted acid sites of HZSM-5 in noble metal/HZSM-5 catalysts play important role in the hydrodesulfurization of thiophene. 

Participation of spillover hydrogen in the hydrodesulfurization of thiophene over Pt/HZSM-5 catalyst was assumed and examined. It was found that catalytic activity of PWSi02(quartz) mixed mechanically with HZSM-5 was higher than that obtained by simple addition of the data for the pure components(Figure 5). This implies that spillover hydrogen on Pt/HZSM-5 catalyst participates in the hydrodesulfurization of thiophene. The mechanism proposed is shown in Scheme 1. 

It was observed that Pt/HZSM-5 was of higher catalytic activity than commercial C0M0/AI2O3 in the hydrodesulfurization of thiophene. Therefore, there is a possibility for using Pt/HZSM-5 as highly active, second generation hydrodesulfurization catalyst for petroleum feedstocks. 

The catalytic activities of fresh and spent catalysts ware deternined for the hydrodesulfurization (HDS) of thiophene in a gas-phase fixed-bed reactor at 400 °C. Following sulfidation in H2/H2S-the reported activities were obtained after 5 h on stream. The thiophene concentration was in the range of 4,9-7-1 vol % and the total pressuretl bar. 

Hatanaka, S., Yamada, M., and Sadakane, O. Hydrodesulfurization of catalytic cracked gasoline. 1. Inhibiting effects of olefins on HDS of alkyl(benzo)thiophenes contained in catalytic cracked gasoline. Industrial Engineering Chemistry Research, 1997, 36, 1519. 

It is evident that 0.5wt%Na-5wt%Rh/USY catalyst shows higher and more stable catalytic activity for the hydrodesulfurization of thiophene than 5wt% Rh/USY and C0M0/AI2O3 catalysts. Therefore, it can be concluded that there is a possibility of usage of Na- Rh/USY as highly active second generation hydrodesulfurization catalyst for petroleum feedstocks. 

Furthermore, it was assumed the existence of spillover hydrogen in the hydrodesulfurization of thiophene over RhAJSY catalyst. Thus, we tried to confirm the existence of spillover hydrogen in the hydrodesulfurization of thiophene over RH/USY catalyst. The catalytic activity of Rh/Si02(quartz) mixed mechanically with USY in the hydrodesulfurization of thiophene was examined. It was found that the activity of mixed catalyst obtained experimentally was higher than that calculated theoretically as shown in Figure 5. 

Preparation and catalytic properties of Ir/alumina and Ir-Mo/alumina sulfide catalysts were studied in hydrodenitrogenation (HDN) of pyridine and hydrodesulfurization (HDS) of thiophene. The Ir added to a Mo/alumina catalyst in amount... 

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