Selective alkylation of xylenes by alcohols on zeolite catalysts

Isakov, Ya. I.; Миначев, Х. М.; Kalinin, V. P.; Isakova, T. A.

doi:10.1007/bf01430639

Cited by 5 publications

(4 citation statements)

References 5 publications

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“…We chose three independent reactions to describe the equilibrium: Table 1 summarizes the results of the equilibrium study obtained. 2,59 a Symbols: tn -time for the system to reach equilibrium; teq -time for studying the system under equilibrium conditions; Kx -ratio of equilibrium concentrations of reaction products in mole fractions to equilibrium concentrations of initial substances; t0.05S -confidence interval for the significance level of 0.05; b [12].…”

Section: Isomerisation and Realkylation Of The O-xylene Alkylation Re...mentioning

confidence: 99%

Case study on 4-Isopropyl-ortho-xylene production

Mazurin,

Shakun,

Nesterova

et al. 2023

From Chemistry Towards Technology Step-by-Step

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We have experimentally studied the alkylation reaction of o-xylene with propylene under kinetic control conditions followed by realkylation under thermodynamic control conditions. The paper provides an analysis of the alkylation reaction products obtained under kinetic control as well as kinetic analysis and thermodynamic analysis of the overalkylation process. The authors have considered the methyl group migration reactions during overalkylation and have given kinetic analyses of these reactions. We found that the optimal method for the preparation of 4 isopropyl-o-xylene is to conduct the process in two stages. The first one is a liquid-phase alkylation of o-xylene under kinetic control at 353 K. The second stage is liquid-phase realkylation of the obtained alkylation reaction mass until reaching thermodynamic equilibrium at a temperature range of 303-353 K under certain conditions. These conditions should ensure minimal migration of methyl groups, i.e. with minimum contact time and alkyl-/aryl- < 0.5 ratio in the reaction products.

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Section: Isomerisation and Realkylation Of The O-xylene Alkylation Re...mentioning

confidence: 99%

Case study on 4-Isopropyl-ortho-xylene production

Mazurin,

Shakun,

Nesterova

et al. 2023

From Chemistry Towards Technology Step-by-Step

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“…Methylation , and ethylation of xylenes , over solid catalysts are relatively well-studied reactions, compared with the isopropylation of xylenes, particularly over solid acid catalysts. In fact, there are only a few reports available in the literature on the isopropylation of xylene isomers − to produce corresponding dimethyl (1-methylethyl) benzenes (also called dimethyl cumenes), which could be used as raw materials for the production of xylenols . Xylenols are important precursors in the production of pesticides, perfumes, pharmaceuticals, heat-transfer media, polymers, special solvents, phenolic resins, electronic equipment, automobiles, and polycarbonates …”

Section: Introductionmentioning

confidence: 99%

“…Isakov et al , have briefly reported that the isopropylation of o -xylene over 0.91NdNa-Y zeolite yields a mixture of dimethyl-isopropyl-benzenes containing 70%−97% 1,2-dimethyl-4-isopropyl benzene, but the isopropylation of p -xylene could not occur on the same catalyst.…”

Section: Introductionmentioning

confidence: 99%

“…20 Xylenols are important precursors in the production of pesticides, perfumes, pharmaceuticals, 21 heat-transfer media, 22 polymers, special solvents, 23 phenolic resins, 24 electronic equipment, automobiles, and polycarbonates. 25 Isakov et al 15,16 have briefly reported that the isopropylation of o-xylene over 0.91NdNa-Y zeolite yields a mixture of dimethyl-isopropyl-benzenes containing 70%-97% 1,2-dimethyl-4-isopropyl benzene, but the isopropylation of p-xylene could not occur on the same catalyst.…”

Section: Introductionmentioning

confidence: 99%

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Alkylation of Xylenes with Isopropyl Alcohol over Acidic Clay Supported Catalysts: Efficacy of 20% w/w Cs_2.5H_0.5PW₁₂O₄₀/K-10 Clay

Yadav

Kamble

2008

Ind. Eng. Chem. Res.

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The alkylation of xylenes with propylene or isopropyl alcohol (IPA) over solid acid catalysts results in the formation of isopropyl xylenes (dimethyl cumenes). However, the use of propylene as an alkylating agent at very high temperatures leads to coke formation, which results in deactivation of the catalyst. The present work covers evaluation of acidic clay-supported catalysts and sulfated zirconia. A variety of solid acid catalysts such as K-10 clay, sulfated zirconia, Filtrol-24, 20% w/w dodecatungstophosphoric acid (H 3 PW 12 O 40 , DTP) supported on K-10 clay, and 20% w/w cesium-substituted dodecatungstophosphoric acid (Cs 2.5 H 0.5 PW 12 O 40 , Cs-DTP) supported on K-10 clay under much milder conditions. The best catalyst to achieve maximum conversion and selectivity was determined to be 20% w/w Cs-DTP/K-10 clay. The reactions were conducted in the liquid phase at relatively low reaction temperatures (160-190 °C). The reaction was performed without using any solvent, and the process subscribes to the principles of green chemistry. The catalytic activity has the following order: 20% w/w Cs-DTP/K-10 clay (most active) > 20% w/w DTP/K-10 clay > Filtrol-24 > sulfated zirconia > K-10 clay (least active). The desired product could be efficiently obtained, with selectivities up to 95% at an isopropanol conversion of 98% after 2 h over 20% w/w Cs-DTP/K-10 clay. This process can be a replacement for the existing processes that are based on zeolites, where high temperature and pressure are required. A systematic investigation of the effects of various operating parameters was accomplished and a mathematical model is developed to describe the reaction pathway and validated against experimental results. An overall second-order kinetic equation was used to fit the data, under the assumption that all the species are weakly adsorbed on the catalytic sites.

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ChemInform Abstract: Selective Alkylation of Xylenes with Alcohols on Zeolite Catalysts.

Isakov¹,

Миначев²,

Kalinin³

et al. 1997

ChemInform

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Selective alkylation of xylenes by alcohols on zeolite catalysts

Cited by 5 publications

References 5 publications

Case study on 4-Isopropyl-ortho-xylene production

Case study on 4-Isopropyl-ortho-xylene production

Alkylation of Xylenes with Isopropyl Alcohol over Acidic Clay Supported Catalysts: Efficacy of 20% w/w Cs_2.5H_0.5PW₁₂O₄₀/K-10 Clay

ChemInform Abstract: Selective Alkylation of Xylenes with Alcohols on Zeolite Catalysts.

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Selective alkylation of xylenes by alcohols on zeolite catalysts

Cited by 5 publications

References 5 publications

Case study on 4-Isopropyl-ortho-xylene production

Case study on 4-Isopropyl-ortho-xylene production

Alkylation of Xylenes with Isopropyl Alcohol over Acidic Clay Supported Catalysts: Efficacy of 20% w/w Cs2.5H0.5PW12O40/K-10 Clay

ChemInform Abstract: Selective Alkylation of Xylenes with Alcohols on Zeolite Catalysts.

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Alkylation of Xylenes with Isopropyl Alcohol over Acidic Clay Supported Catalysts: Efficacy of 20% w/w Cs_2.5H_0.5PW₁₂O₄₀/K-10 Clay