2050-60-4Relevant articles and documents
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Yakhontov et al.
, (1979)
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Method for synthesizing symmetric oxalate by using dimethyl oxalate and alcohols in one step
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Paragraph 0039; 0040, (2019/01/06)
The invention relates to a method for synthesizing symmetric oxalate, in particular to a method for synthesizing the symmetric oxalate by using dimethyl oxalate and alcohols in one step. The symmetricoxalate is synthesized by using the dimethyl oxalate and the high carbon alcohols such as ethanol, propanol, butanol and pentanol as reaction raw materials and by adopting a one-step synthesis method. A catalyst used in the method is a mesoporous-microporous composite multifunctional basic catalyst, and has the advantages that mesopores significantly improve the mass transfer efficiency, while micropores significantly enlarge the specific surface area of a carrier and improve the dispersion of an active center. 10% MgO-5% Al2O3-8% Fe2O3/Na-meso-Y is used as the catalyst, the raw material ethanol and the dimethyl oxalate are enabled to be subjected to reaction under the atmospheric pressure at the temperature of 100 DEG C under the condition that the space velocity is 2 h-1, wherein the molar ratio of the raw material ethanol to the dimethyl oxalate is equal to 20 to 1; the selectivity of the product diethyl oxalate is stabilized to be about 82%, and the steady state operation is performed for 1000h; the catalytic activity and the product selectivity are basically unchanged. The whole reaction path has the characteristics of being short in synthetic route, simple in process flow and high in raw material conversion rate and product selectivity, and enabling the catalyst to be stable and non-deactivated.
Template-free sol–gel synthesis of high surface area mesoporous silica based catalysts for esterification of di-carboxylic acids
More, Pavan M.,Umbarkar, Shubhangi B.,Dongare, Mohan K.
, p. 1247 - 1253 (2016/10/13)
High surface area mesoporous silica based catalysts have been prepared by a simple hydrolysis/sol–gel process without using any organic template and hydrothermal treatment. A controlled hydrolysis of ethyl silicate-40, an industrial bulk chemical, as a silica precursor, resulted in the formation of very high surface area (719?m2/g) mesoporous (pore size 67?? and pore volume 1.19?cc/g) silica. The formation of mesoporous silica has been correlated with the polymeric nature of the ethyl silicate-40 silica precursor which on hydrolysis and further condensation forms long chain silica species which hinders the formation of a close condensed structure thus creating larger pores resulting in the formation of high surface mesoporous silica. Ethyl silicate-40 was used further for preparing a solid acid catalyst by supporting molybdenum oxide nanoparticles on mesoporous silica by a simple hydrolysis sol–gel synthesis procedure. The catalysts showed very high acidity as determined by NH3-TPD with the presence of Lewis as well as Br?nsted acidity. These catalysts showed very high catalytic activity for esterification; a typical acid catalyzed organic transformation of various mono- and di-carboxylic acids with a range of alcohols. The in situ formed silicomolybdic acid heteropoly-anion species during the catalytic reactions were found to be catalytically active species for these reactions. Ethyl silicate-40, an industrial bulk silica precursor, has shown a good potential for its use as a silica precursor for the preparation of mesoporous silica based heterogeneous catalysts on a larger scale at a lower cost.
