نتایج جستجو برای: solid acid
تعداد نتایج: 921902 فیلتر نتایج به سال:
A simple and mild one-pot three-component reaction for the preparation 1,4-dihydropyridines has been developed from various aldehyde substrates, 1,3-dicarbonyl compounds (dimedone) and ammonium acetate (Hantzsch method) in the presence of a catalytic amount of phospho sulfonic acid (PSA) as an efficient and heterogeneous solid acid in EtOH at room temperature. Preparation of PSA is straightforw...
The reaction kinetics of the isomerization 3,4-dichlorobutene-1 to 1,4-dichlorobutene-2 was investigated by using gas-liquid chromatography method in the presence of Fe2O3/MgO as solid catalyst in the temperature range 25-55°C. Fe2O3/MgO has been prepared by the support saturation method, tested in the isomerization of 3, 4-dichlorobutene-1 into 1, 4-dichlorobutene-2. This catalyst shows a high...
in this article, simple, convenient synthesis of 2-aryl-1-arylmethyl-1h-1,3-benzimidazole (1,2-disubstitutedbenzimidazoles) via condensation of 1,2-phenylenediamine and aromatic aldehydes using sba-pr-so3h as a nanoporous solid acid catalyst in green protocol was reported.
the reaction kinetics of the isomerization 3,4-dichlorobutene-1 to 1,4-dichlorobutene-2 was investigated by using gas-liquid chromatography method in the presence of fe2o3/mgo as solid catalyst in the temperature range 25-55°c. fe2o3/mgo has been prepared by the support saturation method, tested in the isomerization of 3, 4-dichlorobutene-1 into 1, 4-dichlorobutene-2. this catalyst shows a high...
A simple and mild one-pot three-component reaction for the preparation 1,4-dihydropyridines has been developed from various aldehyde substrates, 1,3-dicarbonyl compounds (dimedone) and ammonium acetate (Hantzsch method) in the presence of a catalytic amount of phospho sulfonic acid (PSA) as an efficient and heterogeneous solid acid in EtOH at room temperature. Preparation of PSA is straightforw...
knoevenagel condensation between barbituric acid and aldehyde was investigated in the presence of sulfonic acid functionalized nanoporous silica (sba-pr-so3h) and resulted in the formation of arylidene and bis-arylidene barbiturates. excellent yields and short reaction times are related to the high efficiency of sba-pr-so3h that the reactions take place easily in its nano-pores. sba-pr-so3h as ...
A new process for recovering scheelite ores comprises producing a concentrate from the ore, then leaching the concentrate with H_2SO_4 in the presence of H_3PO_4 and Na Cl at atmosphericpressure are discussed. Finely purification of the product will be described. The amounts of dissolution of tungsten in acid depend on the parameters such as time, temperature, type and concentration of acid an...
A green and highly effective solvent-free protocol has been reported for the synthesis of N,N′-alkylidene bisamides via the reaction of arylaldehydes (1 eq.) with primary amides (2 eq.) in the presence of saccharin-N-sulfonic acid (SaSA) as a solid-acid catalyst. The mentioned compounds have been obtained in high yields and short reaction times.
A simple, efficient and clean procedure has been developed for the cleavage of imines C=N bond. Deprotection of imines to their parent carbonyl and amine compounds was achieved using p-toluenesulfonic acid in the solid state condition at 25-45 ˚C. The salient features of this methodology are shorter reaction times, cheap processing, high yields of product and easy availability of the catalyst. ...
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