Influence of Acid Strength and Confinement Effect on the Ethylene Dimerization Reaction over Solid Acid Catalysts: A Theoretical Calculation Study

Solid acid catalysts with acid strength of -14.52 < H0 < -8.2 were prepared by sulfate treatment of the samples of boehmite calcined at 105-800 °C. Two preparation methods were used: impregnation of the calcined boehmite with 3.5 M H2SO4 or mixing of the boehmite samples with anhydrous aluminum sulfate, in both cases followed by calcination in nitrogen at 650 °C. The catalysts were characterized by measurements of surface area, adsorption of pyridine and benzene, acid strength measurements by the indicator method and by catalytic activity tests in the isomerization of cyclohexene, p-xylene and n-hexane. Properties of the catalysts prepared by both methods were comparable.

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ChemInform Abstract: DIRECT MEASUREMENT OF INTERACTION ENERGY BETWEEN SOLIDS AND GASES. II. MICROCALORIMETRIC STUDIES ON THE SURFACE ACIDITY AND ACID STRENGTH DISTRIBUTION OF SOLID ACID CATALYSTS

Chemischer Informationsdienst ◽

10.1002/chin.197842045 ◽

1978 ◽

Vol 9 (42) ◽

Author(s):

T. MASUDA ◽

H. TANIGUCHI ◽

K. TSUTSUMI ◽

H. TAKAHASHI

Keyword(s):

Interaction Energy ◽

Direct Measurement ◽

Solid Acid ◽

Surface Acidity ◽

Acid Strength ◽

Strength Distribution ◽

Solid Acid Catalysts ◽

Acid Catalysts ◽

Acid Strength Distribution

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Measurement of Broensted acid and Lewis acid strength distributions of solid acid catalysts using chemisorption isotherms of Hammett indicators

Industrial & Engineering Chemistry Research ◽

10.1021/ie00082a010 ◽

1988 ◽

Vol 27 (10) ◽

pp. 1792-1797 ◽

Cited By ~ 6

Author(s):

Kenji Hashimoto ◽

Takao Masuda ◽

Hideki Sasaki

Keyword(s):

Lewis Acid ◽

Solid Acid ◽

Acid Strength ◽

Solid Acid Catalysts ◽

Acid Catalysts ◽

Strength Distributions

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Active, Selective, and Recyclable Zr(SO4)2/SiO2 and Zr(SO4)2/Activated Carbon Solid Acid Catalysts for Esterification of Malic Acid to Dimethyl Malate

Catalysts ◽

10.3390/catal10040384 ◽

2020 ◽

Vol 10 (4) ◽

pp. 384

Author(s):

Pei Yu ◽

Can Chen ◽

Guangci Li ◽

Zhong Wang ◽

Xuebing Li

Keyword(s):

Activated Carbon ◽

Electron Density ◽

Malic Acid ◽

Solid Acid ◽

Supported Catalysts ◽

Acid Strength ◽

Solid Acid Catalysts ◽

Acid Catalysts ◽

Bronsted Acid ◽

Brönsted Acid

The esterification of malic acid using traditional homogenous catalysts suffers from the difficulty in reuse of the catalyst and undesirable side reactions. In this work, Zr(SO4)2/SiO2 and Zr(SO4)2/activated carbon (AC) as solid acid catalysts were prepared for malic acid esterification with methanol. The conversion of malic acid over these two catalysts is comparable to that over H2SO4 and unsupported Zr(SO4)2∙4H2O catalysts; however; a 99% selectivity of dimethyl malate can be realized on these two supported catalysts, which is much higher than that of conventional H2SO4 (75%) and unsupported Zr(SO4)2∙4H2O (80%) catalysts, highlighting the critical role of AC and SiO2 supports in tuning the selectivity. We suggest that the surface hydroxyls of AC or lattice O2− ions from SiO2 donate electrons to Zr4+ in Zr(SO4)2/AC and Zr(SO4)2/SiO2 catalysts, which results in the increase in electron density on Zr4+. The enhanced electron density on Zr4+ reduces the degree of H delocalization from crystal water and then decreases the Brønsted acid strength. Consequently, the reduced Brønsted acid strength of Zr(SO4)2/AC and Zr(SO4)2/SiO2 catalysts suppresses the intermolecular dehydration side reaction. In addition, these two supported catalysts can be easily separated from the reaction system by simple filtration with almost no loss of activity.

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