Dissemin is shutting down on January 1st, 2025

Published in

Elsevier, Journal of Catalysis, 1(228), p. 254-258

DOI: 10.1016/j.jcat.2004.08.022

Links

Tools

Export citation

Search in Google Scholar

CO fixation using recoverable chromium salen catalysts: use of ionic liquids as cosolvent or high-surface-area silicates as supports

Journal article published in 2004 by M. Alvaro, C. Baleizao ORCID, D. Das, E. Carbonell, H. Garcia
This paper was not found in any repository, but could be made available legally by the author.
This paper was not found in any repository, but could be made available legally by the author.

Full text: Unavailable

Green circle
Preprint: archiving allowed
Red circle
Postprint: archiving forbidden
Red circle
Published version: archiving forbidden
Data provided by SHERPA/RoMEO

Abstract

Two series of recoverable and reusable chromium salen catalysts for the CO2 addition to styrene epoxide to form cyclic carbonate have been tested under supercritical conditions (100 bar and 80 °C). In one of the cases, tetra-tert-butylsalen chromium (substrate-to-catalyst ratio 875) was dissolved in an ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6), and after the products were extracted with diethyl ether the ionic liquid containing the complex was reused up to four consecutive runs. However, only modest conversions (>50%) and product selectivities (>79%) were achieved under these conditions, although decreasing the substrate-to-catalyst ratio showed some enhancement in the epoxide conversion. In the other system, a chromium salen catalyst was adsorbed on aminopropylsilyl-modified silica and ITQ-2. The solids were tested as heterogeneous catalysts but complete desorption of the complexes was observed after the first use. The best recoverable catalyst of the series was obtained when chromium salen was covalently anchored to silica support through a linker resulting from nucleophilic substitution between aminopropylsilyl-modified silica and chloromethyl-substituted complex. In this case, the solid was still active after the fourth reuse and exhibited 100% carbonate selectivity at about 70% epoxide conversion.