Isopropylation of Naphthalene over .beta. Zeolite

Chu, S.J.; Chen, Yu Wen

doi:10.1021/ie00036a028

Cited by 23 publications

(3 citation statements)

References 19 publications

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“…The low reactant concentrations in the catalytic experiments facilitate the observation of effects on conversion and selectivity of the catalytic reaction due to changes in solvent properties and the state of the reaction medium by pressure variations. This is additionally facilitated because shape selectivity effects are known to be absent in naphthalene conversion with both methanol and 2-propanol over faujasite-type zeolites in the gas phase. , Moreover, acidic faujasite-type catalysts are known to deactivate rapidly in the conversion of naphthalene with either methanol or 2-propanol in the gas phase at ambient pressure. , Therefore, this reaction is also a suitable test for evaluating the potential of supercritical carbon dioxide to extend the catalyst lifetime by the in situ extraction of coke precursors.…”

Section: Introductionmentioning

confidence: 99%

“…17,18 Moreover, acidic faujasite-type catalysts are known to deactivate rapidly in the conversion of naphthalene with either methanol or 2-propanol in the gas phase at ambient pressure. 17,18 Therefore, this reaction is also a suitable test for evaluating the potential of supercritical carbon dioxide to extend the catalyst lifetime by the in situ extraction of coke precursors.…”

Section: Introductionmentioning

confidence: 99%

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Supercritical Carbon Dioxide as a Reaction Medium for the Zeolite-Catalyzed Alkylation of Naphthalene

Gläser

Weitkamp

2003

Ind. Eng. Chem. Res.

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The alkylation of naphthalene with methanol and 2-propanol over the zeolite catalyst LaNaY-73 has been conducted in supercritical carbon dioxide as the reaction medium at 250 °C. Catalytic experiments under flow conditions have been performed at high dilution of the reactants (mole fractions < 0.05) and in the pressure range from 1 to 400 bar. Catalyst deactivation is strongly reduced at supercritical conditions as compared to the one in the gas phase. A pressure increase at supercritical conditions results in a higher catalyst activity. The yield ratio of the major reaction products, i.e., mono-and dialkylnaphthalenes, mainly depends on the alcohol/ naphthalene ratio in the feed and is independent of the reaction pressure and the degree of catalyst deactivation. The distribution of isomers within the mono-and dialkylated products changes with time on stream, according to a shift from thermodynamically to kinetically controlled product formation, the extent being dependent on the reaction pressure and the state of the fluid. The results are discussed in terms of the pressure-dependent properties of the supercritical reaction phase. It is proposed that the properties of the supercritical reaction medium mainly affect the processes taking place on the outer surface of the zeolite crystallites rather than those occurring inside the zeolite pores. For a systematic comparison between the experiments in the gas phase and those in the supercritical phase, the influence of the modified residence time, the carrier gas flow rate, the catalyst mass, and the concentration of the reactants in the feed were studied in naphthalene alkylation with methanol at ambient pressure. Adsorption of naphthalene on the zeolite was conducted in the gas phase at 1 bar and at supercritical conditions at 200 bar.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Supercritical Carbon Dioxide as a Reaction Medium for the Zeolite-Catalyzed Alkylation of Naphthalene

Gläser

Weitkamp

2003

Ind. Eng. Chem. Res.

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“…Therefore, besides 2,6-DAN, more than 10 isomers are formed simultaneously. Selective alkylation of polynuclear aromatics has only received limited attention [1,2], despite the fact that zeolites have been investigated extensively with respect to alkylation of aromatics. Fraenkel et al [3,4] demonstrated the nonselective methylation of naphthalene and 2-methyinaphthalene over Hmordenite and HY zeolites, whereas a high l-selectivity was obtained over HZSM-5 zeolite.…”

Section: Introductionmentioning

confidence: 99%

Isopropylation of naphthalene over modified-mordenite zeolites

Tseng

Chen

1998

React Kinet Catal Lett

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Isopropylation of naphthalene with propylene was carried out over Ce-, Si-, La-, and Mg-modified mordenite zeolites. The reaction was performed in a 500 mL batch reactor at 300~ 8 kg/cm 2, and naphthalene to catalyst weight ratio of 10:1, with excess propylene. It was attempted to eliminate the external acid sites of zeolites by these modifications. The results indicate that the CVD silanation and magnesium or eeritma modification with Mg/A1 or Ce/A1 atomic ratios less than 0.5 can improve the 2,6-DIPN selectivity of mordenites. The improvement of catalyst performance is ascribed to the selective deactivation of acid sites on the external surface of riM zeolites.

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Shape-selective isopropylation of naphthalene over dealuminated mordenites. Increasing?-substitution selectivity by adding water

Schmitz

Chen

1996

Catal Lett

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Isopropylation of Naphthalene over .beta. Zeolite

Cited by 23 publications

References 19 publications

Supercritical Carbon Dioxide as a Reaction Medium for the Zeolite-Catalyzed Alkylation of Naphthalene

Supercritical Carbon Dioxide as a Reaction Medium for the Zeolite-Catalyzed Alkylation of Naphthalene

Isopropylation of naphthalene over modified-mordenite zeolites

Shape-selective isopropylation of naphthalene over dealuminated mordenites. Increasing?-substitution selectivity by adding water

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