Enhanced performance of lipase-catalyzed kinetic resolution of secondary alcohols in monoether-functionalized ionic
Hancheng Zhou1, Jin Chen, Linmin Ye
1State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China. hanchengzhou@hotmail.com
Abstract:
Several cationic monoether-functionalized ionic liquids (MEF-ILs) with different substituents were synthesized and used as media for kinetic resolution of secondary alcohols catalyzed by several lipases. The results indicate that Novozym 435 (an immobilized Candida antarctica Lipase B) had higher efficiency compared to other lipases in deracemization. The alkyl substituents at the 2- and 3-positions in the imidazolium ring of MEF-ILs were found to contribute to the increased enantioselectivity and enhancement of the reaction rate, respectively, while the higher stereo-hindrance of ether bonds decreased the activity. An enantioselectivity higher than 99% with 50% conversion of rac-1-phenylethanol was achieved using the catalyst system comprised of Novozym 435 and the MEF-IL 1-(3-ethoxypropyl)-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide. The catalytic system could be separated and reused without considerable activity loss. MEF-ILs can be a new class of enzyme-benign media suitable for lipase-catalyzed kinetic resolution of secondary alcohols.
Related Concept Videos
Conversion of Alcohols to Alkyl Halides
Preparation of Alcohols via Substitution Reactions
Alcohols can be synthesized from alkyl halides via nucleophilic substitution reactions. The highly polar carbon-halogen bond in the substrate makes halide a good leaving group. The hydroxide ion or water can act as a nucleophile to take the place of halide and form an alcohol. The substitution reactions occur via two different reaction pathways, SN1 or SN2, depending on the nature of carbon attached to the halide.
Primary alcohols are synthesized from primary alkyl halides, and the...
Ethers from Alcohols: Alcohol Dehydration and Williamson Ether Synthesis
Ethers can be prepared from organic compounds by various methods. Some of them are discussed below,
Preparation of Ethers by Alcohol Dehydration
In this method, in the presence of protic acids, alcohol dehydrates to produce alkenes and ethers under different conditions. For example, in the presence of sulphuric acid, dehydration of ethanol at 413 K yields ethoxyethane, whereas it yields ethene at 443 K.
Acid-Catalyzed Dehydration of Alcohols to Alkenes
Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
Carboxylic Acids to Esters: Acid-Catalyzed (Fischer) Esterification Overview


