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The Reductive Amination of Benzaldehyde Over Pd/C Catalysts: Mechanism and Effect of Carbon Modifications on the Selectivity
Author(s) -
Heinen Annemieke W.,
Peters Joop A.,
Bekkum Herman van
Publication year - 2000
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200007)2000:13<2501::aid-ejoc2501>3.0.co;2-s
Subject(s) - chemistry , benzaldehyde , benzylamine , reductive amination , disproportionation , catalysis , selectivity , amination , reactivity (psychology) , organic chemistry , carbon fibers , homogeneous catalysis , inorganic chemistry , medicine , materials science , alternative medicine , pathology , composite number , composite material
The effects of the acidity of the carbon surface on the reactivity and selectivity of carbon supported noble metal catalysts in the reductive amination of benzaldehyde with ammonia was studied. The equilibria involved in the homogeneous solution were studied with 1 H NMR. At the start of the reductive amination, dibenzylimine is rapidly formed, which is subsequently hydrogenated to give dibenzylamine. Benzylamine is formed by disproportionation of dibenzylimine to benzylamine and benzylimine. An increase in the number of acidic sites on the carbon support results in higher reaction rates. This may be ascribed to an acid catalysis in the establishment of relevant homogeneous equilibria and/or reduction of the concentration of the inhibiting gem ‐diamine intermediate at the catalyst surface. A fully selective synthesis of dibenzylamine is achieved by hydrogenation of the intermediate dibenzylimine.