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Catalytic hydroprocessing of 4-methylanisole as a representative of lignin-derived bio-oils was catalyzed by a commercial sulphided CoMo/γ-Al2O3 catalyst in a fixed-bed flow reactor at various space velocities, temperatures, pressures, and feed compositions. An approximate reaction network is presented that accounts for the major products, and approximate kinetics are also presented. The kinetically significant reactions are 4-methylanisole conversion to (a) 4-methylphenol via hydrogenolysis, (b) toluene and benzene via hydrodeoxygenation, (c) cyclohexanone and methylcyclohexanone via hydrogenation, and (d) methylphenol derivatives via alkylation and transalkylation. The formation of toluene and benzene along with water and methanol from 4-methylanisole is inferred to result from direct scission of the Caromatic-O bond. Cleavage of the Cmethyl-O bond is faster than cleavage of the Caromatic-O bond. The main pathway to toluene formation is the hydrogenolysis of the Caromatic-O bond of the intermediate 4-methylphenol. [ABSTRACT FROM AUTHOR]

Alles unter Kontrolle: Eine stereokonvergente formale Hydrogenolyse von N ‐ Sulfonylaminoalkoholen mit einem chiralen Pd ‐ Katalysator und Trifluoressigsäure (TFA) lieferte chirale Amine mit zwei benachbarten Stereozentren (siehe Schema; TFE=Trifluorethanol, Ts= p ‐ Tosyl). Die Reaktion verläuft über eine säurekatalysierte Dehydratation zum Ensulfamid, Enamin/Imin ‐ Isomerisierung und Pd ‐ katalysierte asymmetrische Hydrierung und ergibt die Produkte mit bis zu 94 % ee. [ABSTRACT FROM AUTHOR]

A model of the kinetics underlying the hydrogenolysis of nitriles and amines, catalysed by Pd/C, has been derived. Benzonitrile and benzylamine were used as archetypical compounds to better understand the various reaction pathways involved in these processes. The reaction order under mild conditions (80 °C, 1 bar H2) for the hydrogenolysis of benzylamine was zero order in benzylamine, indicating strong adsorption of benzylamine to the catalyst, whereas the hydrogenation of benzonitrile was found to be first order in benzonitrile, owing to mass transport limitations, explaining the observed selectivities toward hydrogenolysis versus hydrogenation. Significantly, benzylamine itself was found to reversibly poison the hydrogenolysis function of the catalyst, preventing high yields of hydrogenolysis products at low catalyst loadings. [ABSTRACT FROM AUTHOR]

Review: 61 refs. [ABSTRACT FROM AUTHOR]