Hydrogenolysis catalytic selectivity

Engstrom J R, Goodman D Wand Weinberg W H 1986 Hydrogenolysis of n-butane over the (111) and (110)-(1 2) surfaces of iridium a direct correlation between catalytic selectivity and surface structure J. Am. Chem. Soc. 108 4653... 

Catalytic hydrogenolysis of an O-benzyl protective group is a mild, selective method introduced by Bergmann and Zervas to cleave a benzyl carbamate (> NCO—OCH2C6H5 > NH) prepared to protect an amino group during pep-... 

In some catalytic processes, it is necessary to avoid carbon-carbon bond cleavage. For example, isobutane is mainly transformed into its lower alkane homologues (hydrogenolysis products) on metal surfaces, while it can be converted more and more selectively into isobutene when the Pt catalysts contain an increasing amount of Sn (selective dehydrogenation process) [131]. 

Next, we investigated the experimental parameters for hydrogenolysis of Cbz-protected amino acids. It is important to carefully select the experimental parameters so that the reactions are not limited by diffusion of hydrogen to the catalytically active sites. The diffusion of hydrogen can be affected by temperature, agitation speed, as well as the number of catalytically active sites... 

Azaacetals Oxazolidines are formed from ethanolamines and aldehydes or ketones. The C-O bond in oxazolidines can be cleaved selectively by catalytic hydrogenolysis (Scheme 4.15). 

Selective removal of the benzyl ether-protecting group in compound 9 (Fig. 4.1) was made through both transfer hydrogenolysis and the conventional catalytic hydrogenolysis. 

Replacement of the iodine substituent by a hydrogen atom was achieved via selective catalytic hydrogenolysis using 3% Pd/C in MeOH containing AcONa and traces of quinoline at room temperature and 1... 

A comparison of various metals as catalysts for the hydrogenolysis of hydrocarbons reveals a wide variation in catalytic activity, even among such closely related metals as the noble metals of group VIII of the periodic table. Striking differences in the distribution of hydrogenolysis products have also been revealed in studies on selected hydrocarbon reactants. These features are emphasized in the following discussion of activity patterns and product distributions in hydrogenolysis. 

Previously, Ermakov et al. —2— studied Pt-Mo/SiOj catalysts and found that the presence of Mo in Pt-Mo/Si02 catalysts increased the rate of hydrogenolysis by k orders of magnitude compared to Pt/SiOj catalysts and decreased the electron density of Pt as observed from x-ray electron spectroscopy. They interpreted these data in terms of chemical bonding between Pt and Mo and suggested a Pt°-Mo + complex on silica which has catalytic activity and selectivity similar to Rh or Ir rather than to Pt. 

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