Tin Tetra(tert-butoxide) with Acid–Base Additives: Valid Catalyst Precursors for Direct Synthesis of Dimethyl Carbonate from CO2and CH3OH

2011 ◽  
Vol 40 (12) ◽  
pp. 1408-1410 ◽  
Author(s):  
Yoichi Masui ◽  
Shunsuke Haga ◽  
Makoto Onaka
Keyword(s):  
Dimethyl Carbonate ◽  
Direct Synthesis ◽  
Acid Base

Direct synthesis of dimethyl carbonate from CO2 and methanol over CaO–CeO2 catalysts: the role of acid–base properties and surface oxygen vacancies

2017 ◽  
Vol 41 (20) ◽  
pp. 12231-12240 ◽  
Author(s):  
Bin Liu ◽  
Congming Li ◽  
Guoqiang Zhang ◽  
Lifei Yan ◽  
Zhong Li
Keyword(s):  
Oxygen Vacancies ◽  
Dimethyl Carbonate ◽  
Direct Synthesis ◽  
Surface Oxygen ◽  
Acid Base ◽  
Base Properties

The addition of CaO to the CeO2 catalyst had a significant impact on the acid–base properties and amounts of oxygen vacancies on the surface catalyst.

scholarly journals Direct synthesis of N-methylurethanes from primary amines with dimethyl carbonate

2005 ◽  
Vol 77 (10) ◽  
pp. 1719-1725 ◽  
Author(s):  
Pietro Tundo ◽  
Salima Bressanello ◽  
Alessandro Loris ◽  
Gabriel Sathicq
Keyword(s):  
Aromatic Amines ◽  
Dimethyl Carbonate ◽  
Direct Synthesis ◽  
High Yield ◽  
Primary Amines ◽  
Methyl Derivative ◽  
Acid Base ◽  
One Step ◽  
Soft Acid ◽  
Mechanism Of The Reaction

The mechanism of the reaction between amines with dimethyl carbonate (DMC) has been investigated. Whereas in the absence of bases, they give methylation and carboxymethylation reactions without selectivity (BAl2 and BAc2 mechanisms, respectively), in the presence of bases, the BAc2 mechanism prevails. The carbamate already formed reacts further with DMC via the BAl2 mechanism to give the corresponding N-methyl derivative. Such pronounced double selectivity has been explained in terms of Pearson's Hard-Soft Acid-Base (HSAB) theory.Accordingly, N-methylcarbamates have been prepared from primary aliphatic and aromatic amines, either at reflux temperature of DMC (90 °C) or at 230 °C in autoclave. The reaction can be carried out in one step or through the isolation of the carbamate and the subsequent methylation reaction with DMC. This method is the direct synthesis, in high yield and selectivity, of secondary N-methylamines from the corresponding primary amines.

Direct Synthesis of 3,5-Dinitropyrazole Catalyzed by Newly Sulfated Nanosolid Superacid TiO2/ SO

2011 ◽  
Vol 391-392 ◽  
pp. 1296-1301
Author(s):  
Li Min Xi ◽  
Xin Xin Zhang
Keyword(s):  
Direct Synthesis ◽  
Sol Gel ◽  
Acid Base ◽  
Direct Transformation ◽  
Acid Base Titration ◽  
Optimal Reaction Condition ◽  
Superacid Catalyst ◽  
Average Size ◽  
Optimal Reaction ◽  
Xrd And Tem

The newly sulfated nanosolid superacid TiO2/SO4 prepared by sol-gel method was broadly characterized by acid base titration, XRD and TEM, which identified that the superfine solid TiO2/SO4 showing good dispersibility with average size of 27 nm belongs to kind of crystalline nanoparticles. With the help of the catalyst TiO2/SO4, the optimal reaction condition for direct transformation of pyrazole and nitrosonitric acid into 3, 5-Dinitropyrazole was n (pyrazol)=0.10 mol, m (TiO2/SO4 )＝1.5g, V(n-octannol)＝90mL, and V(nitrosonitric acid)＝50mL. Moreover, the optimal yield of the catalytic reaction reached up to 59.4% when the reaction time is 7 hours. The nanosolid superacid catalyst is still of high activity after regenerating eight times by calcination at 600。C.

scholarly journals Gas phase synthesis of dimethyl carbonate from CO2 and CH3OH over Cu-Ni/AC. A kinetic study

2019 ◽  
pp. 88-99 ◽  
Author(s):  
Oscar Felipe Arbeláez-Pérez ◽  
Sara Dominguez Cardozo ◽  
Andrés Felipe Orrego-Romero ◽  
Aida Luz Villa Holguin ◽  
Felipe Bustamante Londoño
Keyword(s):  
Carbon Dioxide ◽  
Catalytic Activity ◽  
Activated Carbon ◽  
Gas Phase ◽  
Dimethyl Carbonate ◽  
Direct Synthesis ◽  
Dispersion Analysis ◽  
Molar Ratio ◽  
Rate Determining Step ◽  
Carbonate Formation

The catalytic activity for dimethyl carbonate formation from carbon dioxide and methanol over mono and bimetallic Cu:Ni supported on activated carbon is presented. Bimetallic catalysts exhibit higher catalytic activity than the monometallic samples, being Cu:Ni-2:1 (molar ratio) the best catalyst; X-Ray diffraction, transmission electron microscopy, and metal dispersion analysis provided insight into the improved activity. In situ FT-IR experiments were conducted to investigate the mechanism of formation of dimethyl carbonate from methanol and carbon dioxide over Cu-Ni:2-1. The kinetics of the direct synthesis of dimethyl carbonate in gas phase over Cu:Ni-2:1 supported on activated carbon catalyst was experimentally investigated at 12 bar and temperatures between 90 oC and 130 oC, varying the partial pressures of CO2 and methanol. Experimental kinetic data were consistent with a Langmuir–Hinshelwood model that included carbon dioxide and methanol adsorption on catalyst actives sites (Cu, Ni and Cu-Ni), and the reaction of adsorbed CO2 with methoxi species as the rate determining step. The estimated apparent activation energy was 94.2 kJ mol-1.

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