Acid zeolites as alcohol racemization catalysts: screening and application in biphasic dynamic kinetic resolution.
Acid zeolites were screened as heterogeneous catalysts for racemization of benzylic alcohols. The most promising zeolites appeared to be H-Beta zeolites, for which the optimal reaction conditions were studied in further detail. The zeolite performance was compared to that of homogeneous acids and acid resins under similar reaction conditions. In a second part of the research, H-Beta zeolites were applied in dynamic kinetic resolution (DKR) of 1-phenylethanol, which was conducted by means of a two-phase approach and which resulted in yields smoothly crossing the 50% border up to 90%, with an enantiomeric excess of >99%. To explore the applicability of this biphasic methodology, several other substrates were examined in the standard racemization reaction and in the biphasic dynamic kinetic resolution.
Wuyts
S
S
Centre for Surface Chemistry and Catalysis, KULeuven, Kasteelpark Arenberg 23, 3001 Leuven, Belgium.
De Temmerman
K
K
De Vos
D E
DE
Jacobs
P A
PA
D002384:Catalysis; D006851:Hydrochloric Acid; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010626:Phenylethyl Alcohol / Q000737:chemistry; D012680:Sensitivity and Specificity; D014105:Tosyl Compounds / Q000737:chemistry; D017641:Zeolites / Q000737:chemistry*
D014105:Tosyl Compounds; D017641:Zeolites; D010626:Phenylethyl Alcohol; D006851:Hydrochloric Acid