A multiphase reaction medium including pressurized carbon dioxide and water for selective hydrogenation of benzonitrile with a Pd/Al2O3 catalyst

Authors:  Hiroshi Yoshida, Yu Wang, Satomi Narisawa, Shin-ichiro Fujita, Ruixia Liu, Masahiko Arai

Abstract:
The hydrogenation of benzonitrile was studied with a Pd/Al₂O₃ catalyst in the presence of pressurized CO₂ and water. This multiphase reaction system was effective for the selective production of the desired primary amine of benzylamine with no deactivation of the catalyst. The enhanced selectivity to the primary amine resulted from its transfer into water phase, which prevented the primary amine from reacting with an intermediate of imine into the secondary amine in the organic phase (benzonitrile). In addition, interactions of CO₂ molecules with the primary amine could also increase its selectivity. In the absence of water, the catalyst was deactivated by the accumulation of a carbamate salt on the surface of catalyst. But this deactivation was avoided by the addition of water because the salt was soluble in water and it did not deposit on the catalyst existing at interfacial layer between the water and organic phases.

Keywords:
Benzonitrile
Selective hydrogenation
Carbon dioxide
Water
Multiphase reaction

Published in: Applied catalysis A: General  (Volume 456, Pages 1-248, 10 April 2013)

Publisher: Elsevier

ISSN Information: 0926-860X

A multiphase reaction medium including pressurized carbon dioxide and water for selective hydrogenation of benzonitrile with a Pd/Al2O3 catalyst

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