nano silica sulfuric acid as a solid acid, was described to be an effective catalyst for one-pot three-component reaction of kojic acid, aryl aldehydes and indoles for the preparation of 2-substituted aryl (indolyl) kojic acid derivatives. the catalyst was prepared by combination of chlorosulfonic acid to nano silica gel. the size of nanoparticles were observed with sem.all prepared compounds w...

a simple highly versatile and efficient sonochemical synthesis of 1,2,4,5-tetrasubstituted and 2,4,5-trisubstituted imidazoles is achieved by condensation of 1,2-dicarbonyl compound, aldehyde, ammonium acetate and primary amine using antimony trichloride immobilized on silica gel (sio2-osbcl2) as a catalyst in ethanol at moderate temperature. operational simplicity, practicability and applicabi...

pyrano [2,3-d] pyrimidinone derivatives have received considerable interest from the pharmaceutical industry due to their wide range of interesting biological and therapeutic properties. nano al2o3 was found to be a highly efficient solid acid catalyst for the preparation of pyrano [2,3-d] pyrimidinone derivatives from the reaction of barbituric acid, aryl aldehyde and malononitrile. al2o3 nano...

The pH optima of family 11 xylanases are well correlated with the nature of the residue adjacent to the acid/base catalyst. In xylanases that function optimally under acidic conditions, this residue is aspartic acid, whereas it is asparagine in those that function under more alkaline conditions. Previous studies of wild-type (WT) Bacillus circulans xylanase (BCX), with an asparagine residue at ...

Chlorodifluoromethane (HCFC-22) is one of the air pollutants that destroy ozone layer and warm earth. In order to degrade HCFC-22, catalytic hydrolysis method currently most effective environmental technology. Herein, we prepare solid acid MoO3/ZrO2 base MgO/ZrO2 catalysts for degradation with a particular focus on revealing effects catalyst preparation methods, calcination temperatures, temper...

Based on starch and series of alkyl benzene sulfonic acid as the materials, a novel carbon-based solid acid catalyst is synthesized using hydrothermal method. This catalyst exhibits much higher catalytic activity in the reaction of esterification of Mono-fatty alcohol polyoxyethylene maleate esters with 1,4-butanediol. The structure of carbon-based solid acid catalyst was charactered by IR and ...

A novel 3D hexadecanuclear heteropolyoxozincate organic framework, IFMC-200, has been successfully synthesized based on a late transition metal-oxygen cluster. IFMC-200 not only represents the first example of (3,4,24)-connected framework but also contains the first 24-connected single metal cluster in a crystal structure. It exhibits superior thermal stability, good water-stability, and even i...

The Bacillus circulans ATCC 31382 β-galactosidase (BgaD) is a retaining-type glycosidase of glycoside hydrolase family 2 (GH2). Its commercial enzyme preparation, Biolacta N5, is used for commercial-scale production of galacto-oligosaccharides (GOS). The BgaD active site and catalytic amino acid residues have not been studied. Using bioinformatic routines we identified two putative catalytic gl...

Nitrogen modified cobalt catalysts supported on carbon were prepared by pyrolysis of the mixture generated from cobalt(II) acetate in aqueous solution of melamine or waste melamine resins, which are widely used as industrial polymers. The obtained nanostructured materials catalyze the transfer hydrogenation of N-heteroarenes with formic acid in the absence of base. The optimal Co/Melamine2@C-70...

A new air-stable nickel precatalyst for C-N cross-coupling is reported. The developed catalyst system displays a greatly improved substrate scope for C-N bond formation to include both a wide range of aryl and heteroaryl electrophiles and aryl, heteroaryl, and alkylamines. The catalyst system is also compatible with a weak base, allowing the amination of substrates containing base-sensitive fun...