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Kai Sundmacher - One of the best experts on this subject based on the ideXlab platform.
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evaluation of different process concepts for the indirect hydration of cyclohexene to Cyclohexanol
2013Co-Authors: Rayees Ahamed Imam, Hannsjorg Freund, Kai Sundmacher, Rudolf P M Guit, Celine Fellay, Robert J MeierAbstract:An indirect hydration process route for the production of Cyclohexanol was proposed by Steyer et al., which uses formic acid as a reactive entrainer (Steyer, F.; Freund, H.; Sundmacher, K.Ind. Eng. Chem. Res. 2008, 47, 9581−9587; Steyer, F.; Sundmacher, K.Ind. Eng. Chem. Res. 2007, 46, 1099–1104). This route overcomes several limitations of the conventional Asahi process for cyclohexene hydration to Cyclohexanol (Steyer, F.; Sundmacher, K.Ind. Eng. Chem. Res. 2007, 46, 1099−1104; Mitsui, O.; Fukuoka, Y. Process for producing cyclic alcohol. U.S. Patent 4,588,846, 1986; Ishida, H.Catal. Surv. Jpn. 1997, 1, 241–246; Ishida, H.; Fukuoka, Y.; Mitsui, O.; Koono, M. Liquid-Phase Hydration of Cyclohexane with Highly Silicious Zeolities. In Zeolites and Microporous Crystals: Proceedings of the International Symposium on Zeolites and Microporous Crystals, Nagoya, August 22–25, 1993; Hattori, T., Yashima, T., Eds.; Studies in Surface Science and Catalysis, Vol. 83; Elsevier: Tokyo, NY, 1994; pp 473–480). A coupled-...
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selective oxidation of Cyclohexanol to cyclohexanone in the ionic liquid 1 octyl 3 methylimidazolium chloride
2011Co-Authors: Long Chen, Hannsjorg Freund, Kai Sundmacher, Teng ZhouAbstract:Ionic liquid (IL) 1-octyl-3-methylimidazolium chloride was found to effectively intensify Cyclohexanol oxidation and resulted in 100% conversion of Cyclohexanol with 100% selectivity to cyclohexanone using hydrogen peroxide as an oxidant and WO3 as a catalyst. The effect of the IL as a solvent is discussed with the support of COSMO-RS theory.
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two step reactive distillation process for Cyclohexanol production from cyclohexene
2009Co-Authors: Amit Katariya, Hannsjorg Freund, Kai SundmacherAbstract:The present work deals with a novel and attractive alternative process route for the production of Cyclohexanol by indirect hydration of cyclohexene using reactive distillation. The proposed two-step process comprises the esterification of cyclohexene with formic acid followed by the hydrolysis of the formed ester. The principle feasibility of this new process has recently been proved by means of residue curve analysis [Steyer et al. Ind. Eng. Chem. Res. 2008, 47, 9581−9587]. In the present contribution, detailed equilibrium stage simulations are performed to identify the optimum design and operating conditions for the coupled reactive distillation column scheme. The simulations reveal that it is possible to achieve almost complete conversion of cyclohexene to Cyclohexanol with a comparatively low amount of catalyst. To the best of our knowledge, this is the first time that such an outstanding performance of a process for the production of Cyclohexanol is reported.
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a novel reactive distillation process for the indirect hydration of cyclohexene to Cyclohexanol using a reactive entrainer
2008Co-Authors: Frank Steyer, Hannsjorg Freund, Kai SundmacherAbstract:In the conventional process for Cyclohexanol production, large amounts of energy are consumed and a considerable quantity of side products is formed. In addition, the process is inherently unsafe. The alternative process of cyclohexene direct hydration requires large amounts of catalyst to overcome kinetic limitations. This publication shows the feasibility of a new route from cyclohexene to Cyclohexanol by means of reactive distillation using formic acid as a reactive entrainer. This allows overcoming kinetic limitations with moderate amounts of catalyst and makes large-scale Cyclohexanol production by reactive distillation an interesting alternative. The suggested coupled reactive distillation process allows producing Cyclohexanol in an inherently safe and energetically advantageous way without incurring significant amounts of side products.
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vle and lle data for the system cyclohexane cyclohexene water Cyclohexanol
2004Co-Authors: Frank Steyer, Kai SundmacherAbstract:The ternary system cyclohexene + water + Cyclohexanol is currently being studied with the aim of carrying out the reaction of cyclohexene and water to Cyclohexanol in a reactive distillation column...
Jianchun Jiang - One of the best experts on this subject based on the ideXlab platform.
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selective hydrogenation of phenol to Cyclohexanol over ni cnt in the absence of external hydrogen
2020Co-Authors: Changzhou Chen, Minghao Zhou, Peng Liu, Brajendra K Sharma, Jianchun JiangAbstract:Transfer hydrogenation is a novel and efficient method to realize the hydrogenation in different chemical reactions and exploring a simple heterogeneous catalyst with high activity is crucial. Ni/CNT was synthesized through a traditional impregnation method, and the detailed physicochemical properties were performed by means of XRD, TEM, XPS, BET, and ICP analysis. Through the screening of loading amounts, solvents, reaction temperature, and reaction time, 20% Ni/CNT achieves an almost complete conversion of phenol after 60 min at 220 °C in the absence of external hydrogen. Furthermore, the catalytic system is carried out on a variety of phenol derivatives for the generation of corresponding Cyclohexanols with good to excellent results. The mechanism suggests that the hydrogenation of phenol to cyclohexanone is the first step, while the hydrogenation of cyclohexanone for the generation of Cyclohexanol takes place in a successive step. Moreover, Ni/CNT catalyst can be magnetically recovered and reused in the next test for succeeding four times.
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water assisted selective hydrodeoxygenation of guaiacol to Cyclohexanol over supported ni and co bimetallic catalysts
2017Co-Authors: Minghao Zhou, Peng Liu, Jianchun JiangAbstract:Hydrodeoxygenation (HDO) of guaiacol, a typical lignin-derived phenolic compound, at relatively mild conditions was studied over γ-Al2O3 and ZSM-5 supported catalysts with Ni and/or Co as active metal. Among various catalysts, NiCo/γ-Al2O3 catalysts exhibited better guaiacol conversion up to 96.1% with Cyclohexanol as the main product in aqueous, due to the proper acidity and interaction between metal particles and support. The effects of process parameters on guaiacol conversion and product distribution were investigated in detail associated with solvent effect. The cleavage of C–O bonds in guaiacol was investigated over NiCo/γ-Al2O3 catalysts in aqueous phase. Phenol was found as the main intermediate with 1-methyl-1,2-cyclohexanediol as another intermediate instead of 2-methoxy-Cyclohexanol. The demethoxylation first happened to form phenol, and then, the aromatic ring was hydrogenated to give Cyclohexanol after further hydrogenation of cyclohexanone.
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Water-Assisted Selective Hydrodeoxygenation of Guaiacol to Cyclohexanol over Supported Ni and Co Bimetallic Catalysts
2017Co-Authors: Minghao Zhou, Peng Liu, Jianchun JiangAbstract:Hydrodeoxygenation (HDO) of guaiacol, a typical lignin-derived phenolic compound, at relatively mild conditions was studied over γ-Al2O3 and ZSM-5 supported catalysts with Ni and/or Co as active metal. Among various catalysts, NiCo/γ-Al2O3 catalysts exhibited better guaiacol conversion up to 96.1% with Cyclohexanol as the main product in aqueous, due to the proper acidity and interaction between metal particles and support. The effects of process parameters on guaiacol conversion and product distribution were investigated in detail associated with solvent effect. The cleavage of C–O bonds in guaiacol was investigated over NiCo/γ-Al2O3 catalysts in aqueous phase. Phenol was found as the main intermediate with 1-methyl-1,2-cyclohexanediol as another intermediate instead of 2-methoxy-Cyclohexanol. The demethoxylation first happened to form phenol, and then, the aromatic ring was hydrogenated to give Cyclohexanol after further hydrogenation of cyclohexanone
Juan J Rodriguez - One of the best experts on this subject based on the ideXlab platform.
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kinetics of the hydrodechlorination of 4 chlorophenol in water using pd pt and rh al2o3 catalysts
2008Co-Authors: Elena Díaz, Angel F. Mohedano, Miguel A. Gilarranz, L. Calvo, José A. Casas, Juan J RodriguezAbstract:The hydrodechlorination of 4-chlorophenol in an aqueous phase was studied in a semicontinuous basket stirred tank reactor using Pd, Pt, and Rh on γ-alumina commercial catalysts (0.5% w/w) under mild reaction conditions. The catalytic activity was studied in the temperature range of 20−40 °C. Pd and Rh showed a higher catalytic activity than Pt. From consumption of 4-chlorophenol and evolution of the reaction products, phenol, cyclohexanone, and Cyclohexanol, a reaction scheme based on a parallel-series pathway and a kinetic model based on pseudo-first-order dependence on 4-chlorophenol have been proposed. Hydrodechlorination of 4-chlorophenol to phenol exhibits the largest apparent kinetic constant for Pd (k1 = 0.42–0.73 h−1) and Pt (k1 = 0.20–0.42 h−1) catalysts, while in the case of Rh, the three reactions, hydrodechlorination of 4-chlorophenol to phenol (k1 = 0.43–0.64 h−1) and hydrogenation of phenol to cyclohexanone (k3 = 0.42–0.78 h−1) and to Cyclohexanol (k4 = 0.38–0.65 h−1), have comparable values...
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hydrodechlorination of 4 chlorophenol in aqueous phase using pd ac catalysts prepared with modified active carbon supports
2006Co-Authors: L. Calvo, Angel F. Mohedano, Miguel A. Gilarranz, José A. Casas, Juan J RodriguezAbstract:Abstract The hydrodechlorination of 4-chlorophenol with hydrogen in aqueous phase has been studied using different home-made Pd/active carbon catalysts. The active carbons employed were subjected to oxidation with nitric acid, hydrogen peroxide and ammonium persulfate and to thermal treatment under nitrogen atmosphere at temperatures ranging from 200 to 900 °C in order to modify their surface chemistry. High conversion values for 4-chlorophenol, well above 95%, were obtained working under mild conditions of temperature (50–75 °C) and pressure (2.4 bar). Modifications on the surface composition of the active carbon support upon oxidation and thermal treatment proved to affect to both conversion of 4-chlorophenol and selectivity towards Cyclohexanol, the less toxic product in the reaction pathway. Increasing thermal treatment temperature showed to be detrimental in both respects whereas oxidation with nitric acid favored a higher selectivity to Cyclohexanol. Those effects can be attributed more specifically to the relative presence of some oxygen groups on the surface of the support. Thus, the highest 4-chlorophenol conversions were obtained with the catalysts whose supports yielded higher amounts of CO2 upon temperature programmed desorption analysis. In particular, carboxylic acid and lactone groups where found to be relevant for a high conversion of 4-chlorophenol and their presence was also important to improve the selectivity to Cyclohexanol. The presence of such groups can be related with a more homogeneous distribution of palladium on the catalysts surface.
Johannes A Lercher - One of the best experts on this subject based on the ideXlab platform.
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hydronium ion catalyzed elimination pathways of substituted Cyclohexanols in zeolite h zsm5
2017Co-Authors: Peter H Hintermeier, Sebastian Eckstein, Mariefel V Olarte, Donald M Camaioni, Eszter Barath, Johannes A LercherAbstract:Hydronium ions in the pores of zeolite H-ZSM5 show high catalytic activity in the elimination of water from Cyclohexanol in aqueous phase. Substitution induces subtle changes in rates and reaction pathways, which are concluded to be related to steric effects. Exploring the reaction pathways of 2-, 3-, and 4-methylCyclohexanol (2-McyOH, 3-McyOH, and 4-McyOH), 2- and 4-ethylCyclohexanol (2-EcyOH and 4-EcyOH), 2-n-propylCyclohexanol (2-PcyOH), and Cyclohexanol (CyOH) it is shown that the E2 character increases with closer positioning of the alkyl and hydroxyl groups. Thus, 4-McyOH dehydration proceeds via an E1-type elimination, while cis-2-McyOH preferentially reacts via an E2 pathway. The entropy of activation decreased with increasing alkyl chain length (ca. 20 J mol–1 K–1 per CH2 unit) for 2-substituted alcohols, which is concluded to result from constraints influencing the configurational entropy of the transition states.
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impact of solvent for individual steps of phenol hydrodeoxygenation with pd c and hzsm 5 as catalysts
2014Co-Authors: Chen Zhao, Johannes A LercherAbstract:Impacts of water, methanol, and hexadecane solvents on the individual steps of phenol hydrodeoxygenation are investigated over Pd/C and HZSM-5 catalyst components at 473 Kin presence of H-2. Hydrodeoxygenation of phenol to cyclohexane includes four individual steps of phenol hydrogenation to cyclohexanone on Pd/C, cyclohexanone hydrogenation to Cyclohexanol on Pd/C, Cyclohexanol dehydration to cyclohexene on HZSM-5, and cyclohexene hydrogenation to cyclohexane on Pd/C. Individual phenol and cyclohexanone hydrogenation rates are much lower in methanol and hexadecane than in water, while rates of Cyclohexanol dehydration and cyclohexene hydrogenation are similar in three solvents. The slow rate in methanol is due to the strong solvation of reactants and the adsorption of methanol on Pd, as well as to the reaction between methanol and the cyclohexanone intermediate. The low solubility of phenol and strong interaction of hexadecane with Pd lead to the slow rate in hexadecane. The apparent activation energies for hydrogenation follow the order E-a phenol > E-a cyclonexanone > E-a cyclohexene, and the sequences of individual reaction rates are reverse in three solvents. The dehydration rates (1.1-1.8 x 10(3) mol mol(BAS)(-1) h(-1))and apparent activation energies (115-124 kJ mol(-1)) are comparable in three solvents. In situ liquid-phase IR spectroscopy shows the rates consistent with kinetics derived from chromatographic evidence in the aqueous phase and verifies that hydrogenation of phenol and cyclohexanone follows reaction orders of 1.0 and 0.55 over Pd/C, respectively. Conversion of Cyclohexanol with HZSM-5 shows first-order dependence in approaching the dehydration-hydration equilibrium in the aqueous phase. Published by Elsevier Inc.
Minghao Zhou - One of the best experts on this subject based on the ideXlab platform.
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selective hydrogenation of phenol to Cyclohexanol over ni cnt in the absence of external hydrogen
2020Co-Authors: Changzhou Chen, Minghao Zhou, Peng Liu, Brajendra K Sharma, Jianchun JiangAbstract:Transfer hydrogenation is a novel and efficient method to realize the hydrogenation in different chemical reactions and exploring a simple heterogeneous catalyst with high activity is crucial. Ni/CNT was synthesized through a traditional impregnation method, and the detailed physicochemical properties were performed by means of XRD, TEM, XPS, BET, and ICP analysis. Through the screening of loading amounts, solvents, reaction temperature, and reaction time, 20% Ni/CNT achieves an almost complete conversion of phenol after 60 min at 220 °C in the absence of external hydrogen. Furthermore, the catalytic system is carried out on a variety of phenol derivatives for the generation of corresponding Cyclohexanols with good to excellent results. The mechanism suggests that the hydrogenation of phenol to cyclohexanone is the first step, while the hydrogenation of cyclohexanone for the generation of Cyclohexanol takes place in a successive step. Moreover, Ni/CNT catalyst can be magnetically recovered and reused in the next test for succeeding four times.
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water assisted selective hydrodeoxygenation of guaiacol to Cyclohexanol over supported ni and co bimetallic catalysts
2017Co-Authors: Minghao Zhou, Peng Liu, Jianchun JiangAbstract:Hydrodeoxygenation (HDO) of guaiacol, a typical lignin-derived phenolic compound, at relatively mild conditions was studied over γ-Al2O3 and ZSM-5 supported catalysts with Ni and/or Co as active metal. Among various catalysts, NiCo/γ-Al2O3 catalysts exhibited better guaiacol conversion up to 96.1% with Cyclohexanol as the main product in aqueous, due to the proper acidity and interaction between metal particles and support. The effects of process parameters on guaiacol conversion and product distribution were investigated in detail associated with solvent effect. The cleavage of C–O bonds in guaiacol was investigated over NiCo/γ-Al2O3 catalysts in aqueous phase. Phenol was found as the main intermediate with 1-methyl-1,2-cyclohexanediol as another intermediate instead of 2-methoxy-Cyclohexanol. The demethoxylation first happened to form phenol, and then, the aromatic ring was hydrogenated to give Cyclohexanol after further hydrogenation of cyclohexanone.
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Water-Assisted Selective Hydrodeoxygenation of Guaiacol to Cyclohexanol over Supported Ni and Co Bimetallic Catalysts
2017Co-Authors: Minghao Zhou, Peng Liu, Jianchun JiangAbstract:Hydrodeoxygenation (HDO) of guaiacol, a typical lignin-derived phenolic compound, at relatively mild conditions was studied over γ-Al2O3 and ZSM-5 supported catalysts with Ni and/or Co as active metal. Among various catalysts, NiCo/γ-Al2O3 catalysts exhibited better guaiacol conversion up to 96.1% with Cyclohexanol as the main product in aqueous, due to the proper acidity and interaction between metal particles and support. The effects of process parameters on guaiacol conversion and product distribution were investigated in detail associated with solvent effect. The cleavage of C–O bonds in guaiacol was investigated over NiCo/γ-Al2O3 catalysts in aqueous phase. Phenol was found as the main intermediate with 1-methyl-1,2-cyclohexanediol as another intermediate instead of 2-methoxy-Cyclohexanol. The demethoxylation first happened to form phenol, and then, the aromatic ring was hydrogenated to give Cyclohexanol after further hydrogenation of cyclohexanone
