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Liquid‐Phase Hydrogenation of Unsaturated Aldehydes: Enhancing Selectivity of Multiwalled Carbon Nanotube‐Supported Catalysts by Thermal Activation
Author(s) -
Machado Bruno F.,
Gomes Helder T.,
Serp Philippe,
Kalck Philippe,
Faria Joaquim L.
Publication year - 2010
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.200900230
Subject(s) - cinnamaldehyde , cinnamyl alcohol , thermogravimetric analysis , catalysis , chemisorption , selectivity , chemistry , adsorption , iridium , metal , platinum , inorganic chemistry , nanotube , chemical engineering , carbon nanotube , materials science , organic chemistry , nanotechnology , engineering
Abstract Platinum and iridium organometallic precursors are used to prepare nanosized, thermally stable multiwalled carbon nanotube‐supported catalysts. The materials are characterized by N 2 adsorption at 77 K, temperature‐programmed desorption coupled with mass spectrometry, H 2 chemisorption, transmission electron microscopy and thermogravimetric analysis; they are tested in the selective hydrogenation of cinnamaldehyde to cinnamyl alcohol under mild conditions (363 K and 1 MPa). A thermal activation at 973 K is found to have a very positive effect over both activity and selectivity, leading to selectivities of approximately 70 %, at 50 % conversion, regardless of the active metal phase (Pt or Ir). Since no noticeable differences in the metal particle sizes are detected, the results are interpreted in light of an enhanced metal/support interaction. This effect, induced by the removal of oxygenated surface groups, is thought to change the adsorption mechanism of the cinnamaldehyde molecule.