Next Article in Journal
Next Article in Special Issue
Previous Article in Journal
Previous Article in Special Issue
Molecules 2010, 15(11), 8400-8424; doi:10.3390/molecules15118400
Review

Combining the Benefits of Homogeneous and Heterogeneous Catalysis with Tunable Solvents and Nearcritical Water

1,2
, 2,3
, 2,3 and 1,2,*
Received: 11 October 2010; Accepted: 8 November 2010 / Published: 16 November 2010
(This article belongs to the Special Issue Heterogeneous Catalysis)
Download PDF [456 KB, uploaded 18 June 2014]
Abstract: The greatest advantage of heterogeneous catalysis is the ease of separation, while the disadvantages are often limited activity and selectivity.  We report solvents that use tunable phase behavior to achieve homogeneous catalysis with ease of separation.  Tunable solvents are homogeneous mixtures of water or polyethylene glycol with organics such as acetonitrile, dioxane, and THF that can be used for homogeneously catalyzed reactions. Modest pressures of a soluble gas, generally CO2, achieve facile post-reaction heterogeneous separation of products from the catalyst. Examples shown here are rhodium-catalyzed hydroformylation of 1-octene and p-methylstyrene and palladium catalyzed C-O coupling to produce o-tolyl-3,5-xylyl ether and 3,5-di-tert-butylphenol. Both were successfully carried out in homogeneous tunable solvents followed by separation efficiencies of up to 99% with CO2 pressures of 3 MPa. Further examples in tunable solvents are enzyme catalyzed reactions such as kinetic resolution of rac-1-phenylethyl acetate and hydrolysis of 2-phenylethyl acetate (2PEA) to 2-phenylethanol (2PE). Another tunable solvent is nearcritical water (NCW), whose unique properties offer advantages for developing sustainable alternatives to traditional processes. Some examples discussed are Friedel-Crafts alkylation and acylation, hydrolysis of benzoate esters, and water-catalyzed deprotection of N-Boc-protected amine compounds.
Keywords: tunable solvent; nearcritical water; pressure induced heterogeneous separations; homogeneous catalysis tunable solvent; nearcritical water; pressure induced heterogeneous separations; homogeneous catalysis
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Export to BibTeX |
EndNote


MDPI and ACS Style

Fadhel, A.Z.; Pollet, P.; Liotta, C.L.; Eckert, C.A. Combining the Benefits of Homogeneous and Heterogeneous Catalysis with Tunable Solvents and Nearcritical Water. Molecules 2010, 15, 8400-8424.

AMA Style

Fadhel AZ, Pollet P, Liotta CL, Eckert CA. Combining the Benefits of Homogeneous and Heterogeneous Catalysis with Tunable Solvents and Nearcritical Water. Molecules. 2010; 15(11):8400-8424.

Chicago/Turabian Style

Fadhel, Ali Z.; Pollet, Pamela; Liotta, Charles L.; Eckert, Charles A. 2010. "Combining the Benefits of Homogeneous and Heterogeneous Catalysis with Tunable Solvents and Nearcritical Water." Molecules 15, no. 11: 8400-8424.



Molecules EISSN 1420-3049 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert