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Tungstophosphoric acid supported on MCM-41 mesoporous silicate: An efficient catalyst for the di-tert-butylation of cresols with tert-butanol in supercritical carbon dioxide

Paper ID Volume ID Publish Year Pages File Format Full-Text
44035 46000 2006 9 PDF Available
Title
Tungstophosphoric acid supported on MCM-41 mesoporous silicate: An efficient catalyst for the di-tert-butylation of cresols with tert-butanol in supercritical carbon dioxide
Abstract

Tungstophosphoric acid (HPW) supported on MCM-41 mesoporous silicate was an excellent catalyst for the tert-butylation of cresols in supercritical CO2. The tert-butylation of p-cresol gave 2,6-di-tert-butyl-4-methylphenol (2,6-DTBPC) in high yield (the best yield: 58%) in supercritical CO2; however, zeolites, H-Y and H-beta, gave only 2-tert-butyl-4-methylphenol (2-TBPC) because of their limitation in pore size. The yield of 2,6-DTBPC over HPW(30)/MCM-41 was maximum at 110 °C, and further increase in temperature decreased the yield. There was the optimal CO2 pressure on the yield of 2,6-DTBPC at 10 MPa, and further increase of the pressure resulted in rapid decrease in the yield.Thermogravimetric analysis of used catalysts showed that the deactivation is minimized in supercritical CO2 compared to the other reaction media such as hexane as solvent and without solvent under N2 atmosphere. HPW(30)/MCM-41 was recyclable without significant loss of catalytic activity, and retained mesoporous structure even after three recycles.The tert-butylation of o- and m-cresols over HPW(30)/MCM-41 gave the 2,4-di-tert-butyl-6-methylphenol, 2,4-di-tert-butyl-5-methylphenol, respectively, in good to moderate yields.

Keywords
Tungstophosphoric acid; MCM-41; Supercritical CO2; tert-Butylation; p-Cresol; 2,6-Di-tert-butyl-4-methylphenol
First Page Preview
Tungstophosphoric acid supported on MCM-41 mesoporous silicate: An efficient catalyst for the di-tert-butylation of cresols with tert-butanol in supercritical carbon dioxide
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 310, 17 August 2006, Pages 155–163
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis