Dehydration of Methanol to Dimethyl Ether over Heteropoly Acid Catalysts: The Relationship between Reaction Rate and Catalyst Acid Strength

ACS Catalysis ◽  
2015 ◽  
Vol 5 (12) ◽  
pp. 7186-7193 ◽  
Author(s):  
Walaa Alharbi ◽  
Elena F. Kozhevnikova ◽  
Ivan V. Kozhevnikov
Keyword(s):  
Dimethyl Ether ◽  
Reaction Rate ◽  
Heteropoly Acid ◽  
Acid Strength ◽  
Acid Catalysts ◽  
The Relationship

TiO2-supported heteropoly acid catalysts for dehydration of methanol to dimethyl ether: relevance of dispersion and support interaction

2015 ◽  
Vol 5 (1) ◽  
pp. 484-491 ◽  
Author(s):  
Rosa María Ladera ◽  
Manuel Ojeda ◽  
José Luis G. Fierro ◽  
Sergio Rojas
Keyword(s):  
Dimethyl Ether ◽  
Heteropoly Acid ◽  
Heteropoly Acids ◽  
Acid Catalysts ◽  
Support Interaction

TiO2-supported heteropoly acids are very active catalysts for DME production from methanol. Due to the interaction with the support, the most active catalysts are obtained when a monolayer of HPA is deposited on the support.

Preparation of Strong Acid Catalysts by Sulfate Treatment of Calcined Boehmite

1992 ◽  
Vol 57 (11) ◽  
pp. 2241-2247 ◽  
Author(s):  
Tomáš Hochmann ◽  
Karel Setínek
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Aluminum Sulfate ◽  
Solid Acid ◽  
Strong Acid ◽  
Acid Strength ◽  
Solid Acid Catalysts ◽  
Acid Catalysts ◽  
Preparation Methods ◽  
Indicator Method

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.

scholarly journals Are rate and selectivity correlated in iridium-catalysed hydrogen isotope exchange reactions?

2021 ◽  
Author(s):  
Daria S. Timofeeva ◽  
David M Lindsay ◽  
W. J. Kerr ◽  
David James Nelson
Keyword(s):  
Functional Groups ◽  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Reaction Rate ◽  
Exchange Reactions ◽  
Reaction Selectivity ◽  
Hydrogen Isotope Exchange ◽  
The Relationship

Herein we examine the relationship between reaction rate and reaction selectivity in iridium-catalysed hydrogen isotope exchange (HIE) reactions directed by Lewis basic functional groups. We have recently develped a directing...

scholarly journals New green perspective to dihydropyridines synthesis utilizing modified heteropoly acid catalysts

2021 ◽  
Author(s):  
Mohamed Mokhtar ◽  
Tamer S. Saleh ◽  
Katabathini Narasimharao ◽  
Ebtesam Al-Mutairi
Keyword(s):  
Heteropoly Acid ◽  
Acid Catalysts

One-Pot Synthesis of 1-Benzoylpyrene over Heteropoly Acid Catalysts

2012 ◽  
Vol 560-561 ◽  
pp. 294-299
Author(s):  
Xiao Qing Lu ◽  
Min Xing ◽  
Ai Xia Pan ◽  
Yin Yin Wu ◽  
Ji Min Xie ◽  
...  
Keyword(s):  
Benzoyl Chloride ◽  
Heteropoly Acid ◽  
Active Catalyst ◽  
Catalytic Synthesis ◽  
Acid Catalysts ◽  
Acylation Reaction ◽  
One Pot ◽  
Experimental Parameters ◽  
Product Separation ◽  
Ft Ir

A novel one-pot catalytic synthesis of 1-benzoylpyrene through acylation of pyrene with benzoyl chloride catalyzed by various Keggin type heteropoly acids (salts) was investigated. Pure 1-benzoylpyrene was obtained and the structure of 1-benzoylpyrene was identified by GC/MS, FT-IR and 1H NMR spectra. H3PW12O40 (PW) was found to be the most active catalyst in the acylation. The yield and the selectivity of 1-benzoylpyrene were up to 97.6 % and 100 %, respectively. The effects of experimental parameters on the catalytic acylation reaction and the recycling performance of PW catalyst were studied. PW catalyst shows well catalytic activity after running for 5 times. The facile product separation and the recycling performance of PW catalyst is expected to contribute to the development of clean and environmentally friendly strategy for the synthesis of 1-benzoylpyrene.

scholarly journals Selective synthesis of thioethers in the presence of a transition-metal-free solid Lewis acid

2016 ◽  
Vol 12 ◽  
pp. 2627-2635 ◽  
Author(s):  
Federica Santoro ◽  
Matteo Mariani ◽  
Federica Zaccheria ◽  
Rinaldo Psaro ◽  
Nicoletta Ravasio
Keyword(s):  
Reaction Rate ◽  
Solid Acid ◽  
Amorphous Solid ◽  
Solid Acid Catalysts ◽  
Acid Catalysts ◽  
Alumina Catalyst ◽  
Reaction Conditions ◽  
Solvent Free Conditions ◽  
Wide Range ◽  
Silica Alumina

The synthesis of thioethers starting from alcohols and thiols in the presence of amorphous solid acid catalysts is reported. A silica alumina catalyst with a very low content in alumina gave excellent results in terms of both activity and selectivity also under solvent-free conditions. The reaction rate follows the electron density of the carbinol atom in the substrate alcohol and yields up to 99% and can be obtained for a wide range of substrates under mild reaction conditions.

scholarly journals Photoreduction of Cr(VI) Ions in Aqueous Solutions by UV/ Photocatalytic Processes

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Chih Ming Ma ◽  
Yung Shuen Shen ◽  
Po Hsiang Lin
Keyword(s):  
Aqueous Solutions ◽  
Reaction Rate ◽  
Removal Rate ◽  
Experimental Results ◽  
Order Kinetic ◽  
Solution Ph ◽  
Relationship Of ◽  
The Relationship ◽  
Photocatalytic Processes ◽  
Order Kinetic Equation

This study discussed the photoreduction of Cr(VI) ions in aqueous solutions by UV/TiO2photocatalytic processes under various operational factors. Experimental results showed that the removal rate of Cr(VI) increased with decreasing solution pH values and with increasing dosages of organic compounds, indicating that the recombination rate of electrons and h+can be retarded in the reaction systems by the addition of the scavenger, thus raising the reaction rate of Cr(VI). The relationship of the chemical reaction rate of Cr(VI), TiO2dosage, and changes of Cr(VI) concentration was expressed by the pseudo-first-order kinetic equation. Comparing the experimental results of two different doping metals in modified TiO2photoreduction systems, the removal rate of Cr(VI) by the Ag/TiO2process is larger, possibly because the electron transferring ability of Ag is superior to that of Cu. However, the photoreduction rates of Cr(VI) by modified UV/TiO2processes are worse than those by a nonmodified commercial UV/TiO2process.

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