Sulfur bifunctional catalysts

However, Michaud et al. and Landau et al reported that the use of an acid zeolite catalyst and classical HDS catalyst bifunctional catalyst was a very efficient way to desulfurize alkylated DBT. In this case, they observed that acid zeolite catalyst achieves isomerization of the more hindered sulfur atom alkylated DBT (viz. 46DMDBT) to compounds for which the sulfur atom is not anymore hindered by the methyl groups (viz. 37DMDBT). 

Aggarwal, V. K., Bell, L., Coogan, M. P., Jubault, P. Bifunctional catalysts for asymmetric sulfur ylide epoxidation of carbonyl compounds. J. Chem. Soc., Perkin Trans. 1 1998, 2037-2042. 

Comparison data were presented, that demonstrate the use of the polysiloxane material as an advantageous substitute for organic cation exchange resins, sulfuric acid, p-toluene sulfonic acid and acidic zeolites. It is demonstrated, that materials like 1 and 2 are cost-efficient and reliable catalysts in esterification, alkylation, and condensation, whereas use of the bifunctional catalyst 3 gives excellent conversions in hydrogenolysis reactions in general. 

The objective of this investigation was to examine the effect of water vapor on the reduction of sulfur dioxide with carbon monoxide on an iron-alumina bifunctional catalyst and to devise double-catalyst beds to cope with the deleterious effect of water. The catalyst temperature of the first bed in this double-bed system was varied to adjust the ratio of reactants entering the second bed in order to maximize the removal of sulfurous gases. 

Generally, the use of other heterocycles besides quinoline would be considered modifications of the original Reissert protocol. This reaction has been extended to convert an acyl chloride into an aldehyde through a one-pot process by adding the acyl chloride to a solution of quinoline and hydrocyanic acid, and subsequent steam distillation of the entire mixture with sulfuric acid. In addition, the formation of the Reissert compound has been modified to occur enantioselectively using TMSCN as the nucleophilic species in the presence of a Lewis acid-Lewis base bifunctional catalyst. Moreover, tri-n-butyltin cyanide and acetone cyanohydrin are also used for the preparation of the Reissert compounds. 

For Ti02 and Z1O2, it is well known that sulfation induces a strong increase of acidity [17] and the participation of an add mechanism could then account for this promotion of activity. This mechamsm can be described as a bifunctional process oxidation of NO to NO on Cu sites, and nitration of a product of the oxidation of decane on the acid fiinction(8). The preparation of the catalyst must have a great influence on the activity. This has been shown by the comparison of three Cu/TiC catalysts prepared in different conditions one in which titania is first treated with sulfuric acid, then by Cu acetate (denominated Cu 04/Ti02, containing 0.S wt% Cu, 0.6 wt% S), one in which Cu is... 

Hydrotreating. In order to successfully reform a naphtha with the conventional bifunctional reforming catalyst, heteroatoms must be reduced to a level such that they will not deactivate the reforming catalyst. Sulfur and nitrogen levels of well below 5 ppm seem to be required for conventional reforming catalysts while levels below 1 ppm appear necessary for the newer bimetallics. The assumption was made that, if sulfur and nitrogen levels could be reduced to specification, the chemical oxygen levels would follow. 

Study of the Simultaneous Deactivation by Coke and Sulfur of Naphtha Reforming Catalysts using a Bifunctional Test Reaction... 

---