Catalytic ring hydrogenation of phenol under supercritical carbon dioxide

Rode, Chandrashekhar V.; Joshi, Upendra A.; Sato, Osamu; Shirai, Masayuki

doi:10.1039/b304344d

Cited by 99 publications

(61 citation statements)

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“…Supercritical carbon dioxide (T c ¼ 304:2 K and P c ¼ 7:38 MPa) can be made miscible with light gasses and aromatics by proper choice of pressure and temperature conditions. Higher reaction rates and hence higher productivity, and easy separation of liquid products without using organic solvents can be achieved by conducting catalytic hydrogenations with solid catalysts in supercritical carbon dioxide medium [5,6,[15][16][17][18][19][20][21][22][23]. Especially, this technique is very effective for the hydrogenation of solid substrates to liquid products, which are soluble in supercritical carbon dioxide.…”

Section: Introductionmentioning

confidence: 99%

Tuning cis-decalin Selectivity in Naphthalene Hydrogenation Over Carbon-supported Rhodium Catalyst Under Supercritical Carbon dioxide

et al. 2006

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Catalytic hydrogenation of naphthalene to decalin was studied over a carbon-supported rhodium catalyst in supercritical carbon dioxide solvent at 333 K, and the results were compared with those in an organic solvent. cis-, trans-Decalin and tetralin were formed from the beginning of the reaction in supercritical carbon dioxide. Higher concentration of hydrogen in carbon dioxide solvent and on the active site, and also the suppression of desorption of partially hydrogenated tetralin molecules from the active site would be responsible for higher selectivity to cis-decalin in supercritical carbon dioxide than that in an organic solvent.

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Section: Introductionmentioning

confidence: 99%

Tuning cis-decalin Selectivity in Naphthalene Hydrogenation Over Carbon-supported Rhodium Catalyst Under Supercritical Carbon dioxide

et al. 2006

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“…Rode et al showed that a charcoal-supported rhodium (Rh/C) catalyst was highly active for the ring hydrogenation of phenol and cresols in scCO 2 , and high conversions of phenol were achieved over Rh/C under such conditions as 328 K, 10 MPa H 2 , and 12 MPa CO 2 [22]. Carbon supported Pd, Ru and Pt catalysts were much less active than Rh/C.…”

Section: Introductionmentioning

confidence: 99%

Hydrogenation of phenol with supported Rh catalysts in the presence of compressed CO2: Its effects on reaction rate, product selectivity and catalyst life

Fujita

Yamada

Akiyama

et al. 2010

The Journal of Supercritical Fluids

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Hydrogenation of phenol to cyclohexanone and cyclohexanol in/under compressed CO 2 was examined using commercial Rh/C and Rh/Al 2 O 3 catalysts to investigate the effects of CO 2 pressurization on the total conversion and the product selectivity. Although the total rate of phenol hydrogenation with Rh/C was lowered by the presence of CO 2 , the selectivity to cyclohexanone was improved at high conversion levels > 70%. On the other hand, the activity of Rh/Al 2 O 3 was completely lost in an early stage of reaction. The features of these multiphase catalytic hydrogenation reactions using compressed CO 2 were studied in detail by phase behavior and solubility measurements, in situ high pressure FTIR for molecular interactions of CO 2 with reacting species and formation/adsorption of CO on the catalysts, and simulation of reaction kinetics using a simple model. The CO 2 pressurization was shown to suppress the hydrogenation of cyclohexanone to cyclohexanol, improving the selectivity to cyclohexanone.The formation and adsorption of CO were observed for the two catalysts at high CO 2 pressures in the presence of H 2 , which was one of important factors retarding the rate of hydrogenation in the presence of CO 2 . It was further indicated that the adsorption of CO on Rh/Al 2 O 3 was strong and caused the complete loss of its activity.

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“…When converting 1-and 2-phenylethanol into the respective cyclohexanes with Ru/C, a selectivity of more than 80 % (with a conversion rate of more than 60 %) was found [68]. The other noble metal catalysts studied were found to be less suitable than in the case of phenol conversion [68][69][70].…”

Section: Hydrogenations (For Surveys See [46 47])mentioning

confidence: 86%

Heterogeneous Catalysis in Supercritical Media: 1. Carbon Dioxide

Kruse

Vogel

2007

Chem Eng & Technol

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Dedicated to Prof. Dr.-Ing. Jens Weitkamp on the occasion of his 65th birthdayOver the past few years, supercritical fluids have received considerable interest as reaction media. Supercritical fluids combine properties of gases and liquids. Densities are lower than in the liquid phase, but significantly higher than in the gas phase. This makes supercritical fluids excellent solvents for a variety of substances. The good dissolution capacity exists only in or near the supercritical range. Reaction products can be separated, for instance, simply by decreasing temperature and pressure. This may be used to intensify the process as complex separation processes, like distillation, are avoided.

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Catalytic ring hydrogenation of phenol under supercritical carbon dioxide

Abstract: A charcoal-supported rhodium catalyst was highly active for the ring hydrogenation of phenol and cresols under supercritical carbon dioxide.

Cited by 99 publications

References 14 publications

Tuning cis-decalin Selectivity in Naphthalene Hydrogenation Over Carbon-supported Rhodium Catalyst Under Supercritical Carbon dioxide

Tuning cis-decalin Selectivity in Naphthalene Hydrogenation Over Carbon-supported Rhodium Catalyst Under Supercritical Carbon dioxide

Hydrogenation of phenol with supported Rh catalysts in the presence of compressed CO2: Its effects on reaction rate, product selectivity and catalyst life

Heterogeneous Catalysis in Supercritical Media: 1. Carbon Dioxide

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