Hydrogenolysis reactions occurring

For example, when the Sn/Ptj ratio=0.85, the selectivity to isobutene reaches 99.5% (and the lifetime is considerably increased). This increase in selectivity for isobutene can be simply explained by the site isolation effect [25-41]. It is now generally admitted that the coke formation, isomerization and hydrogenolysis reactions occur mostly on large surfaces of platinum, since more than one platinum atom is involved in the reaction mechanism (Scheme 18.15) [220,... 

Solvents may have an important influence on the reduction. No reaction occurred on attempted hydrogenolysis of the azetidine (7) over 5% Pd-on-C in ethanol, but in acetic acid reduction proceeded smoothly to give the 1-hydroxyazctidine (8) (137). 

Reactions occurring in hydrotreatment include both hydrogenation and hydrogenolysis reactions. 

The general reaction occurring in hydrodesulfurization has been described in Section 2.1.1. The most studied model compound is DBT. The reactivity towards hydrogenation of the phenyl substituents already mentioned (Section 2.1.1) is also observed in the hydroprocessing of sulfur compounds. The reactivity towards hydrogenolysis of the C-S bond masks the effects associated to aromatics hydrogenation. The DBT reaction network is sketched in Fig. 8 the pseudo-first-order reaction constants measured by Houalla [68] have been included. 

Such hydrogenolysis indicates that the following two parallel reactions occur and that their ratio will vary substantially with degree and location of methyl group in the catalytic hydrogenolysis of asymmetric diarylmethanes (Ar—CH2—Ar ) ... 

The hydrogenolysis and isomerization of methyloxirane take place via a mechanism in which hydrogen is involved in the rate-determining step. This reaction occurs on the step sites. 

Under the initially neutral conditions of hydrogenation, the production of the phenylpropanols as the major products represents a stabilized form of the initially released units. Loss of oxygen from the a- and impositions by a hydrogenolysis reaction may well have occurred. The results of the studies, using initially alkaline conditions whereby phenyl-ethanoid products result, help support the belief that alkali facilitates the 0-7 carbon-carbon cleavage and that oxygen originally was associated with the 0-carbon atom. 

Normand et al. have studied Pd deposited on several metal oxide supports in reactions of methylcyclopropane hydrogenolysis, 3-methylhexane aromatization, and in Fischer-Tropsch catalysis 23 Three classes of oxides were studied, those that were not reducible such as Re2C>3, those with anion vacancies produced during reduction like Ce02, and those with intrinsic anion vacancies such as nonstoichiometric Pt60h and Tb407. Hydrogenolysis reactions were found to occur on Pd sites whereas aromatization reactions were believed to be... 

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