02378nas a2200241   4500008004100000022001400041245013600055210006900191260009500260300001000355490000800365520138100373653004001754653003401794653004101828653002701869100002201896700002901918700001601947700002201963700002101985856013002006       2007                        eng d  a0021-951700aStereoselective hydrogenation of tert-butylphenols over charcoal-supported rhodium catalyst in supercritical carbon dioxide solvent0 aStereoselective hydrogenation of tertbutylphenols over charcoals  a525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USAbACADEMIC PRESS INC ELSEVIER SCIENCEcNOV  a57-680 v2523 a<p>Hydrogenation of 2-, 3-, and 4-tert-butylphenols was studied over a charcoal- supported rhodium catalyst in supercritical carbon dioxide (scCO(2)) solvent, and the results were compared with those in organic solvents. In the hydrogenation of 4-tert-butylphenol, a higher cis ratio for 4-tert-butylcyclohexanol (0.79) was obtained in scCO(2) (10 MPa) than in 2-propanol (0.70) and cyclohexane (0.64) under similar conditions of hydrogen pressure (2 MPa) and temperature (313 K). In the case of 2-tert-butylphenol, the cis ratio for 2-tert-butylcyclohexanol was as high as 0.95 in both scCO(2) and 2-propanol (hydrogen pressure, 2 MPa; reaction temperature, 313 K). In the case of hydrogenation of 3-tert-butylphenol, the cis ratio decreased with the progression of consecutive hydrogenation of 3-tert-butylcyclohexanone intermediate. In addition, the stereoselectivity to cis-tert-butylcyclohexanols in scCO(2) was improved in the presence of hydrochloric acid. It was found that the protons of hydrochloric acid accelerated the hydrogenation of the intermediates, tert-butylcyclohexanones, to the corresponding cis-tert-butylcyclohexanols. The hydrogenation mechanism of tert-butylphenols, particularly the enhanced selectivity to cis-tert-butylcyclohexanols in scCO(2), is postulated based on the observed reaction profiles. (c) 2007 Elsevier Inc. All rights reserved.</p>10acharcoal-supported rhodium catalyst10astereoselective hydrogenation10asupercritical carbon dioxide solvent10atert-butylcyclohexanol1 aHiyoshi, Norihito1 aRode, Chandrashekhar, V.1 aSato, Osamu1 aTetsuka, Hiroyuki1 aShirai, Masayuki  uhttps://library.ncl.res.in/content/stereoselective-hydrogenation-tert-butylphenols-over-charcoal-supported-rhodium-catalyst-0