Hydrogenolysis hydrogenation

Progress and prospects in hydrogenation, hydrogenolysis, and desulfurization of thiophenes with soluble metal complexes 98ACR109. 

Under the conditions used for the reductive cleavage of the O—N bond in isoxazoles, a similar reaction readily occurs with isoxa-zolines, e.g. on treatment with organomagnesium compounds and on catalytic hydrogenation.- Hydrogenolysis of the O—N bond (180 181 182 183) was used to elucidate the structure of isoxa-zolones from -ketoesters. -... 

Dan and Henbesi (ii) demonslraied ihai ihe amount of salts remaining in platinum oxide catalysts had an important bearing on the hydrogenation-hydrogenolysis ratio of allylic functions. Hydrogenolysis is inhibited by salts remaining from the catalyst preparation or by salts such as sodium nitrite, cyanide, or hydroxide added later. 

Other reactions that occur during hydrocracking are the fragmentation followed by hydrogenation (hydrogenolysis) of the complex asphaltenes and heterocyclic compounds normally present in the feeds. 

The last vertical column of the eighth group of the Periodic Table of the Elements comprises the three metals nickel, palladium, and platinum, which are the catalysts most often used in various reactions of hydrogen, e.g. hydrogenation, hydrogenolysis, and hydroisomerization. The considerations which are of particular relevance to the catalytic activity of these metals are their surface interactions with hydrogen, the various states of its adatoms, and admolecules, eventually further influenced by the coadsorbed other reactant species. 

Vinyl ethers and vinyl esters are not employed extensively in organic transformations. During the synthesis of phlegmarine, however, the stereogenic center at C-10 was to be introduced stereoselectively by catalytic hydrogenation-hydrogenolysis of the vinyl triflate (Scheme 4.7). 

During the synthesis of 2-pyridones, hydrogenation-hydrogenolysis of the ketone intermediate was performed on different catalysts (Scheme 4.24).56,57... 

Oximes Amines can be prepared by the catalytic hydrogenation— hydrogenolysis of oximes over nickel or noble metal catalysts. Nickel is used usually in the presence of ammonia. Noble metals are used under mild conditions. The stereochemistry of the reaction depends on the circumstances. On Ra-Ni the trans-2-alkylcyclohexylamine (41) was the main product,529 whereas on palladium the cis product (42) was produced (Scheme 4.137).530... 

For the replacement of halogen by hydrogen - hydrogenolysis of the carbon-halogen bond - many reduction methods are available. Since breaking of carbon-halogen bonds is involved, the ease of hydrogenolysis decreases in... 

Search for effective organic promoters. Selective and active catalysts for Reaction 4 should not only be effective carbonylation catalysts, but also be highly effective in hydrogenation-hydrogenolysis reactions in the presence of CO. The most obvious parameters affecting activity and selectivity include Rh/Ru ratio, partial CO and H2 pressures, temperature, solvent type, and type of iodide promoter. 

Emphasizes hydrogenation, hydrogenolysis, C-C coupling, amination, and oxidation... 

Transition metals are used as catalysts for a variety of reactions hydrogenation, hydrogenolysis and isomerization of hydrocarbons (group VIII metals), oxidation of... 

In this section we shall consider the results recorded in the literature that pertain to the structures of the adsorbed species. Kinetic or catalytic aspects, as could be relevant to hydrogenation, hydrogenolysis, or metathesis processes, will be treated in Part 11. Spectra of the much-investigated alkenes are discussed in detail in Part I. The spectra of the other principal types of hydrocarbon adsorbates, viz. alkynes, alkanes, cycloalkanes, and aromatics, will be analyzed in Part II. Most results are available for the type-molecules ethene, ethyne, ethane, and benzene as well as for the metals, Pt, Pd, Ni, Rh, and Ru. 

Hydrodemetallation pathways for Ni-etioporphyrin and Ni-tetra(3-methylphenyl)porphyrin are shown in Fig. 20. Both are characterized by a sequential hydrogenation-hydrogenolysis global mechanism, but important differences are apparent. Ware and Wei (1985a) rationalized the differences in porphyrin reactivity on the basis of porphyrin molecular structure. Structural differences on the periphery of the metalloporphyrin, in particular the substituent groups at the /3-pyrrolic and methine bridge... 

With deasphalted oils an alternative explanation is required to rationalize the linear relationships. Gajardo et al. (1982) postulate the linear relationships between HDM and HDS, and HDM and HDN are the result of similar active catalytic sites for each heteroatom species. This interpretation is compatible with model compound studies revealing similar sequential hydrogenation-hydrogenolysis reaction pathways for HDM, HDS, and HDN (see Section IV,A). 

Keywords epoxide, tra/rs-epoxy succinic acid, hydrogenation, hydrogenolysis, alcohol... 

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