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Asymmetric hydrogenation of o ‐Cresol and m ‐Cresol catalyzed by silica‐supported methylcellulose–L‐alanine–Pd complex
Author(s) -
Huang Kai,
Hu Jie,
Huang MeiYu,
Jiang YingYan
Publication year - 2001
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.92
Subject(s) - catalysis , chemistry , solvent , palladium , nuclear chemistry , cresol , biopolymer , polymer chemistry , organic chemistry , polymer , phenol
Silica‐supported methylcellulose–L‐alanine–palladium complex (SiO 2 ‐MC–LA–Pd) has been prepared and found to be a high optically active catalyst for asymmetric hydrogenation of o ‐cresol and m ‐cresol to give ( S )‐2‐methylcyclohexanone and ( R )‐3‐methylcyclohexanone, respectively, at 25 ° C and under an atmospheric hydrogen pressure. The optical yields of ( S )‐2‐methylcyclohexanone and ( R )‐3‐methylcyclohexanone amounted to 91.5 and 68.5%, respectively, when optimum Pd content in SiO 2 ‐MC–LA–Pd complex, reaction temperature and solvent were selected. SiO 2 ‐MC–LA–Pd catalyst also has shown high stability. The optical yields for ( S )‐2‐methylcyclohexanone and ( R )‐3‐methylcyclohexanone were kept over 90 and 60%, respectively, when the catalyst was reused several times. Moreover, SiO 2 ‐MC–LA–Pd complex is an economical catalyst. The methylcellulose is an abundant natural biopolymer and the procedure for preparation of the complex is very simple. Copyright © 2001 John Wiley & Sons, Ltd.