Solvent effects in liquid-phase reactionsI. Activity and selectivity during citral hydrogenation on Pt/SiO2 and evaluation of mass transfer effects

Mukherjee, Sayak; Vannice, M. A.

doi:10.1016/j.jcat.2006.06.021

Cited by 158 publications

(138 citation statements)

References 58 publications

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“…where (10) For to MBE transformation to MBA and MBY to dimers, the following expressions can be developed:…”

Section: Internal Mass Transfermentioning

confidence: 99%

Three-Phase Catalytic Hydrogenation of a Functionalized Alkyne: Mass Transfer and Kinetic Studies with in Situ Hydrogen Monitoring

Bruehwiler¹,

Semagina²,

Grasemann³

et al. 2008

Ind. Eng. Chem. Res.

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Systematic studies of mass transfer interactions with intrinsic reaction kinetics were performed for the threephase selective hydrogenation of 2-methyl-3-butyn-2-ol (MBY) to 2-methyl-3-buten-2-ol (MBE) over a modified Pd/CaCO 3 catalyst under solvent free conditions. Hydrogen concentration in the liquid phase (C H2,b ) was monitored in situ during the catalytic reaction by means of the "Fugatron" analyzer. Reactions were carried out in an autoclave at different stirring rates at two concentrations of hydrogen (5 and 13 mol · m -3 ). For stirring speeds higher than 1500 rpm no influence of gas-liquid mass transfer was observed. Hydrogen liquid-solid (L-S) mass transfer was found to be negligible, whereas the MBY mass L-S transfer becomes important at high MBY conversions at high hydrogen concentration. Low stirrer speed caused the reaction rate and MBE selectivity to decrease. No internal mass transfer limitations were observed, and conditions for the kinetic regime were found. The kinetics modeled followed the Langmuir-Hinshelwood mechanism and was consistent with the experimental data.

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“…where (10) For to MBE transformation to MBA and MBY to dimers, the following expressions can be developed:…”

Section: Internal Mass Transfermentioning

confidence: 99%

Three-Phase Catalytic Hydrogenation of a Functionalized Alkyne: Mass Transfer and Kinetic Studies with in Situ Hydrogen Monitoring

Bruehwiler¹,

Semagina²,

Grasemann³

et al. 2008

Ind. Eng. Chem. Res.

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“…Citronellal was an essential compound in flavoring and perfumery industries. Simple hydrogenation of citral results (Scheme 1) [5] is in the formation of various products, such as citronellal, citronellol, geraniol, nerol, 3,7-dimethyl-1-octanal and isopulegol, menthol. Hence, it is particularly challenging to control the product selectivity as well as the conversion in the citral hydrogenation.…”

Section: Introductionmentioning

confidence: 99%

Effect of Alkali Carbonate/Bicarbonate on Citral Hydrogenation over Pd/Carbon Molecular Sieves Catalysts in Aqueous Media

Krishna

Ramakrishna

Soni

et al. 2016

MRC

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The efficient citral hydrogenation was achieved in aqueous media using Pd/CMS and alkali additives like K 2 CO 3 . The alkali concentrations, reaction temperature and the Pd metal content were optimized to enhance the citral hydrogenation under aqueous media. In the absence of alkali, citral hydrogenation was low and addition of alkali promoted to ~92% hydrogenation without reduction in the selectivity to citronellal. The alkali addition appears to be altered the palladium sites. The pore size distribution reveals that the pore size of these catalysts is in the range of 0.96 to 0.7 nm. The palladium active sites are also quite uniform based on the TPR data. The catalytic parameters are correlated well with the activity data.

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“…The advantages presented by these catalysts [19,20], in general, do not permit the industrial production of biodiesel, mainly due to the high temperatures (120-200°C), alcohol to oil molar ratio (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) and reaction time (3-8 hours) [21]). To accelerate the reaction rates, some works presented the possibility of including co-solvents in the reaction medium, towards enhancing the solubility and mass transfer between oil and methanol [22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

“…To accelerate the reaction rates, some works presented the possibility of including co-solvents in the reaction medium, towards enhancing the solubility and mass transfer between oil and methanol [22][23][24][25]. The use of co-solvent in a liquid phase can affect the activity of the catalyst by the modification of its surface characteristics [26], react with the reactants/products and also to promote an enhancement in the viscosity of the reaction medium [27], especially when high temperatures are used [28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Production of biodiesel from soybean and Jatropha Curcas oils with KSF and amberlyst 15 catalysts in the presence of co-solvents

Calgaroto

Mazutti

et al. 2013

sustain chem process

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Experimental conditions for the production of fatty acid methyl esters (FAME) from Jatropha curcas and soybean oils using two acid heterogeneous catalysts (Amberlyst15 and KSF) was optimized, in the presence of different co-solvents (THF, acetone, petroleum ether and n-hexane) in a batch reactor at fixed conditions: oil to methanol molar ratio (1:9), catalyst concentration (4.8 wt%), co-solvent mass ratio (1:1), 160°C and 6 hours. Results showed that the use of co-solvents led to a reduction in the FAME conversion. Higher conversions were obtained for Jatropha curcas compared to soybean oil. The Amberlyst15 presented an enhancement in the catalytic activity after regeneration, providing high biodiesel conversions compared to the fresh resin. The catalyst also presented stability after 5 cycles of reuse. Activity lost was observed for KSF after 2 successive batch experiments, probably due to a deactivation of acid sites.

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Solvent effects in liquid-phase reactionsI. Activity and selectivity during citral hydrogenation on Pt/SiO2 and evaluation of mass transfer effects

Cited by 158 publications

References 58 publications

Three-Phase Catalytic Hydrogenation of a Functionalized Alkyne: Mass Transfer and Kinetic Studies with in Situ Hydrogen Monitoring

Three-Phase Catalytic Hydrogenation of a Functionalized Alkyne: Mass Transfer and Kinetic Studies with in Situ Hydrogen Monitoring

Effect of Alkali Carbonate/Bicarbonate on Citral Hydrogenation over Pd/Carbon Molecular Sieves Catalysts in Aqueous Media

Production of biodiesel from soybean and Jatropha Curcas oils with KSF and amberlyst 15 catalysts in the presence of co-solvents

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