Determination of styrene hydrogenation surface kinetics through detailed simulation of the hydrogen uptake curve

Abstract

The styrene hydrogenation over Pd/C in a three-phase dead-end stirred tank reactor has been simulated.The mass transfer coefficients were calculated based on experimental data. The fast intrinsic reaction kinetics did not allow the effects of the gas-liquid and liquid-solid mass transfer to be ignored. A rigorous model is described which includes all mass transfer steps with a Langmuir-Hinshelwood model of the surface chemical reaction. The adsorption constants of hydrogen, styrene and ethylbenzene on catalyst active sites were estimated from a single experimental reaction profile. The parameterised model was validated against 6 further sets of experimental data which were not included in the parameters' estimation procedure. Results indicate the ethylbenzene, styrene and hydrogen adsorption to have an equilibrium constant of 148.34 L mol −1 , 847.72 L mol −1 and 19 984 L mol −1 , respectively. The intrinsic rate constant for the 4.63%Pd/C catalyst is 0.0542 mol g cat −1 s or 1.17 mol g Pd −1 s −1 . This work demonstrates that the analysis of the whole hydrogenation reaction profile in combination with detailed mass transfer resistance evaluation can provide fundamental system properties.

Kinetics of One-Pot Regioselective Cohydrogenation of Styrene Oxide and Aryl Alkenes: A Step toward Sustainable Development of a Novel Integrated Process for 2-Phenylethanol Production

“…In contrast, the unsaturated double bonds present in AMS and STY were prone to hydrogenation at a much higher rate than the epoxy bond in STOX. These findings can be found at par with the allied information found in the literature. , Additionally, the absence of any compounds resulting from the hydrogenation of the benzene ring from both AMS and STOX in the product mixture falls in line with Pd/C catalysts’ claims to be regioselective toward nonaromatic hydrogenation …”

“…These findings can be found at par with the allied information found in the literature. 19,28 Additionally, the absence of any compounds resulting from the hydrogenation of the benzene ring from both AMS and STOX in the product mixture falls in line with Pd/C catalysts' claims to be regioselective toward nonaromatic hydrogenation. 34 The effect of varying speed of agitation on the reaction performance was studied to assess the external mass-transfer resistance.…”

“…Kinetic analysis of STOX hydrogenation has been carried out, and estimated parameters have been reported by researchers. , On the other hand, the kinetics of AMS and STY hydrogenation has also been proposed in the literature. , To the best of the authors’ knowledge, simultaneous one-pot hydrogenation of STOX and AMS and STOX and STY has never been studied before. Experimental observations in this study suggested that the relative rate of AMS and STY hydrogenation were much higher than that of STOX, and consequently, both AMS and STY were converted fully to CUM and EB, respectively, within the first few minutes of the reaction.…”

“…They include chemicals such as methoxy methylbenzene, phenylacetaldehyde, and 1PEA (routes a , c , and d in Figure ). Moreover, compounds such as alpha-methylstyrene (AMS) − (routes e – g in Figure ), ACP − (routes h and i in Figure ), and STY , (routes j – n in Figure ) are also prone to hydrogenation and can convert into numerous products. A detailed report of information available in the literature is elucidated in Section S.1 of the Supporting Information.…”

Decoupling the relative rate of hydrogen uptake via convection and mass transfer by a single catalytic pellet in a scaled down trickle bed reactor

“…The bed porosity, of the reactor when fully packed was determined to be 39%. To approximate ′′ we use the observed rate constant reported by Stamatiou and Muller who used the same 5% Pd/C powder characterised and discussed in Section 4.1 for the hydrogenation of styrene in an agitated slurry reactor (27). Based on the weight of palladium on the catalyst support and the hydrogen concentration in the fluid, , an observed rate constant at 32 ℃ was determined;…”