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Microwave synthesized quaternized celluloses for cyclic carbonate synthesis from carbon dioxide and epoxides

Paper ID Volume ID Publish Year Pages File Format Full-Text
40030 45843 2013 9 PDF Available
Title
Microwave synthesized quaternized celluloses for cyclic carbonate synthesis from carbon dioxide and epoxides
Abstract

•Insoluble quaternized celluloses were synthesized with microwave radiations.•Cycloaddition of CO2 with epoxides were catalyzed by quaternized celluloses.•Role of vicinal hydroxyls and halide ion in cyclic carbonate synthesis investigated.

The efficacy of microwave irradiation for the quaternization of ethylenediamine-functionalized celluloses (en-Cell), as well as the catalytic activity of the resultant microwave quaternized celluloses (mQCs) in the cycloaddition of carbon dioxide with epoxide substrates under solvent-free conditions has been studied. A series of mQCs with various alkyl chains and anions were synthesized and characterized by solid-state 13C NMR, FT-IR, XPS, and EA. The mQCs employed were found to yield cyclic carbonates in an atom-efficient manner with excellent selectivity (99%) under a low catalytic loading (0.4 mol%) and elevated pressures of CO2 (1.2 MPa), thereby realizing a turnover number (TON) of 242. A quite remarkable BET surface area ranging from 50 to 71 m2 g−1 for the microwave-synthesized quaternized celluloses was obtained, compared to the very low surface area of 2 m2 g−1 of the starting cellulosic material. The indispensable role played by the vicinal hydroxyl groups of cellulose during catalysis was investigated using hydroxyl-protected celluloses. By rationalizing the obtained results, a plausible mechanism, in which all the functional moieties of the mQCs operate synergistically, is proposed. The mQC catalysts were found to exhibit excellent thermal and moisture stability, and they were reusable more than six times without any significant reduction in activity.

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Keywords
Quaternized cellulose; Microwave; Carbon dioxide; Cyclic carbonate; Heterogeneous catalysis
First Page Preview
Microwave synthesized quaternized celluloses for cyclic carbonate synthesis from carbon dioxide and epoxides
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 467, 2 October 2013, Pages 17–25
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis