Alkylation of Toluene over Basic Catalysts—Key Requirements for Side Chain Alkylation

Palomares, Emilio; Eder‐Mirth, G.; Rep, M.; Lercher, Johannes A.

doi:10.1006/jcat.1998.2253

Cited by 99 publications

(71 citation statements)

References 48 publications

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“…It has been reported that the side-chain alkylation of toluene with methanol requires a cooperative action of acid/base pairs for efficiently promoting the rate-limiting step in the reaction mechanism [5,6] but other authors suggested that catalyst selectivity is essentially governed by the overall acid-base strength as measured by Sanderson electronegativity [7]. In particular, Palomares et al [8] studied by in situ infrared spectroscopy the sorption and reaction of toluene and methanol over basic catalysts with the aim of ascertaining the requirements for side chain alkylation.In an attempt to obtain more insight on the active site requirements for the alkylation of toluene with methanol on alkali-exchanged zeolites, we recently explored a new approach for relating the solid surface properties with its catalytic performance based on selective acid-base poisoning [9]. We concluded that active sites involving surface acid-base pairs are required for promoting the rate-limiting step of the reaction mechanism.…”

Section: Introductionmentioning

confidence: 98%

Side-chain alkylation of toluene with methanol on Cs-exchanged NaY zeolites: effect of Cs loading

et al. 2005

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The side-chain alkylation of toluene with methanol was studied on Cs-exchanged NaY zeolites containing up to 31% Cs (exchange degree, ED, up to 70%). Formation of styrene and ethylbenzene was significant only on Na(Cs)Y zeolites of ED higher than about 40%. Bimolecular side-chain alkylation reaction would require a proper surface geometric configuration of O d) -Cs + pairs that is achieved only on Cs-rich zeolites. In contrast, the side reaction forming carbon monoxide from methanol increases monotonically with increasing ED because it is essentially controlled by the basicity of the oxygen lattice.

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Section: Introductionmentioning

confidence: 98%

Side-chain alkylation of toluene with methanol on Cs-exchanged NaY zeolites: effect of Cs loading

et al. 2005

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“…Thermally activated LDH catalysts possess long lifetimes, high stability, selectivity and reproducibility. LDHs can be used as solid base catalysts in olefin isomerization [51], nucleophilic halogenation [52], alkylation [53], epoxidation [54] and Claisen-Schmidt reactions [55]. LDHs formed on the surface of a support also show good catalytic properties.…”

Section: New Catalytic Materialsmentioning

confidence: 99%

Layered intercalated functional materials based on efficient utilization of magnesium resources in China

Lin

Evans

et al. 2010

Sci. China Chem.

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Mg-based layered intercalated functional materials of the layered double hydroxide type are a significant class of magnesium compounds. Based on long-term studies of these materials in the State Key Laboratory of Chemical Resource Engineering in Beijing University of Chemical Technology, two principles of "using the intended application of a material as a guide to its structure design and synthesis process" and "the design of controlled intercalation processes in the light of future production processing requirements" have been developed. To achieve these objectives, the composition of the host layers and guest interlayer anions was tailored at the microlevel, while the mesostructure and macrostructure were controlled to fabricate different kinds of Mg-based layered intercalated functional materials. These materials have diverse applications in key areas such as catalysis, the environment, and construction, and as polymer additives. Therefore, China's magnesium resources may be utilized more efficiently for the benefit of society.Mg-based layered intercalated structure, functional material, magnesium resource, efficient utilization, structure design

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“…It is shown that introduction of Mg 2+ and Zn 2+ in combination with Cs 2 CO 3 significantly increased the yields of ethylbenzene and styrene in comparison with their yields on alkali forms of zeolite X.Alkylation of toluene with methanol in the side chain is described as one of the alternative methods for the preparation of styrene and ethylbenzene -chemical products with considerable industrial value.The reaction occurs in the presence of basic catalysts as first shown by Sidorenko et al [1,2] using zeolites of the faujasite type modified with alkali metal ions.According to current ideas, alkylation in the side chain requires the presence of both basic and acidic centers on the surface of the catalyst -Lewis acid-base pairs, characterized by a definite spacial distribution to facilitate their cooperative effect in the rate determining steps of the process [3][4][5][6]. Activation of the methyl group of toluene is carried out with participation of the basic centers of the catalyst, while the acidic centers interact with the benzene ring, stabilizing it.…”

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confidence: 99%

“…According to current ideas, alkylation in the side chain requires the presence of both basic and acidic centers on the surface of the catalyst -Lewis acid-base pairs, characterized by a definite spacial distribution to facilitate their cooperative effect in the rate determining steps of the process [3][4][5][6]. Activation of the methyl group of toluene is carried out with participation of the basic centers of the catalyst, while the acidic centers interact with the benzene ring, stabilizing it.…”

mentioning

confidence: 99%

“…Dehydrogenation of methanol occurs to form formaldehyde and its stabilization on the catalyst surface. The steric limitations within the pores of the zeolite play an important role, determining the spacial orientation of the toluene molecule [4,5]. Thus the construction of synthetic catalysts for the alkylation of toluene with methanol in the side chain requires the conjunction in a single reaction space both functional (energy, concentration of basic and acidic centers, their interaction and optimum ratio) and structural factors (localization and steric configuration of the active centers, size of the pores in the catalyst, etc.…”

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confidence: 99%

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Influence of ion-exchange and impregnation modification of zeolite X on its catalytic properties in the alkylation of toluene with methanol

et al. 2006

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The dependence of the activity and selectivity of ion-exchanged forms of zeolite X with incorporated cesium process in alkylation of toluene with methanol in the side chain on the nature of the ion-exchanged cations (Na + , Cs + , Mg 2+ , Zn 2+ ) has been established. It is shown that introduction of Mg 2+ and Zn 2+ in combination with Cs 2 CO 3 significantly increased the yields of ethylbenzene and styrene in comparison with their yields on alkali forms of zeolite X.Alkylation of toluene with methanol in the side chain is described as one of the alternative methods for the preparation of styrene and ethylbenzene -chemical products with considerable industrial value.The reaction occurs in the presence of basic catalysts as first shown by Sidorenko et al. [1,2] using zeolites of the faujasite type modified with alkali metal ions.According to current ideas, alkylation in the side chain requires the presence of both basic and acidic centers on the surface of the catalyst -Lewis acid-base pairs, characterized by a definite spacial distribution to facilitate their cooperative effect in the rate determining steps of the process [3][4][5][6]. Activation of the methyl group of toluene is carried out with participation of the basic centers of the catalyst, while the acidic centers interact with the benzene ring, stabilizing it. Dehydrogenation of methanol occurs to form formaldehyde and its stabilization on the catalyst surface. The steric limitations within the pores of the zeolite play an important role, determining the spacial orientation of the toluene molecule [4,5]. Thus the construction of synthetic catalysts for the alkylation of toluene with methanol in the side chain requires the conjunction in a single reaction space both functional (energy, concentration of basic and acidic centers, their interaction and optimum ratio) and structural factors (localization and steric configuration of the active centers, size of the pores in the catalyst, etc.).Zeolites acting as catalysts are known to be used in ion-exchanged forms. Exchange of the sodium cation by the less electronegative cations of rubidium and cesium leads to redistribution of the electron density and consequently to an increase in the electron donor capacity of the oxygen atoms in the lattice which affects as the weak Lewis base centers [2]. So introduction of Cs + cations into the lattice of zeolite X in an amount corresponding to a high degree of ion exchange (for example by use of hydrothermal methods) leads to increased selectivity of the process with respect to styrene [7,8]. Results of recent studies show that oxides (hydroxides) of alkali metals introduced into the zeolite considerably increase the yield of products of alkylation in the side chain [9][10][11][12]. In this way formation of nanophase clusters of alkali metal oxides are formed in situ within the body of the zeolite. It has been established that the base centers of such oxide guests are stronger than the base centers of the lattice of the zeolite [11]. Usachev et al. [13] have shown tha...

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Alkylation of Toluene over Basic Catalysts—Key Requirements for Side Chain Alkylation

Cited by 99 publications

References 48 publications

Side-chain alkylation of toluene with methanol on Cs-exchanged NaY zeolites: effect of Cs loading

Side-chain alkylation of toluene with methanol on Cs-exchanged NaY zeolites: effect of Cs loading

Layered intercalated functional materials based on efficient utilization of magnesium resources in China

Influence of ion-exchange and impregnation modification of zeolite X on its catalytic properties in the alkylation of toluene with methanol

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