Activity and Selectivity of Palladium Catalysts during the Liquid-Phase Hydrogenation of Phenol. Influence of Temperature and Pressure

González‐Velasco, Juan R.; González-Marcos, M.P.; Arnaiz, Sixto; Gutiérrez-Ortiz, José I.; Gutiérrez-Ortiz, M.A.

doi:10.1021/ie00043a004

Cited by 29 publications

(18 citation statements)

References 12 publications

(14 reference statements)

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“…On the basis of these results, it can be concluded that the phenol hydrogenation proceeds through the pathways illustrated in Scheme 1: phenol is sequentially hydrogenated through cyclohexanone to cyclohexanol (paths i and iii) and directly to cyclohexanol (path ii). In contrast to the present results, almost 100% selectivity to cyclohexanone was obtained with supported Pd catalysts in both the gas-phase [1][2][3][4][5][6][7][8][9][10][11][12] and liquid-phase [13][14][15][16]25] hydrogenation reactions. The direct formation of cyclohexanol from phenol (path ii) is unlikely to occur with these Pd catalysts.…”

Section: Reaction Pathways Of Phenol Hydrogenationcontrasting

confidence: 99%

“…In the cases of vapor phase hydrogenation, high temperatures are needed, which usually cause catalyst deactivation by coking during the reaction. In a few studies, liquid phase hydrogenation of phenol was carried out with Pd catalysts [13][14][15][16]. However, high reaction temperatures or long reaction time were still required to obtain high phenol conversions.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Reaction Pathways Of Phenol Hydrogenationcontrasting

confidence: 99%

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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“…Numerous catalysts were used for maleic acid isomerization . Thiourea is used most commonly because of its low cost . Other catalysts, such as inorganic acid, KCN, Br 2 , NH 4 Br, etc.…”

Section: Introductionmentioning

confidence: 99%

Study on the Isomerization of Maleic Acid to Fumaric Acid without Catalyst

Gao

Chen

Rothenberg

et al. 2018

Bulletin Korean Chem Soc

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Fumaric acid is an important food additive and industrial intermediate compound. The traditional methods of producing fumaric acid were catalyzed by maleic acid isomerization. In this study, isomerization of maleic acid in water without catalyst was investigated at elevated temperature, which addressed the problem of sewage discharge. HPLC analysis showed maleic acid converted into fumaric acid and small amount of malic acid simultaneously. The effects of concentration of maleic acid, reaction temperature, reaction time, and stirring on the yield of fumaric acid were investigated. The optimum reaction conditions were also explored. The results showed the isomerization of maleic acid reached equilibrium at about 1 h, stirring did not affect the reaction rate, and conversion due to the monomolecular mechanism. In order to achieve "zero emission," the recycle of filter liquor was also studied. The pH of filter liquor changing signifies the lower pH was in favor of the conversion of maleic acid to fumaric acid. The high yield and recyclability suggested that this process had promising application in fumaric acid production.

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“…Generally, the hydrogenation of phenol is carried out in the vapour phase and supported palladium catalysts have been reported as the best catalysts for this reaction. [2][3][4][5][6][7][8][9] There has been hardly any work reported for liquid phase hydrogenation of phenol except that by Velasco et al 10 Supported metal catalysts are useful for hydrogenation processes in industry. However, in the case of vapor phase hydrogenation, high temperatures are needed and coking during reaction causes catalyst deactivation.…”

mentioning

confidence: 99%