silica sulfuric acid is found to catalyze efficiently the condensation of o-phenylenediamines with various linear and cyclic ketones to afford the corresponding 1,5-benzodiazepines in quantitative yields under solvent-free conditions at room temperature

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...

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...

Polyetheretherketone (PEEK) is a material suitable for frameworks of fixed dental prostheses. The effect of different surface treatments on the bond strength of PEEK bonded to human dentin was evaluated. One hundred PEEK cylinders (3 mm×3 mm) were divided into five groups according to surface treatment: silica coating, sandblasting with 45 μm Al2O3 particles, etching with 98% sulfuric acid for ...

Silica sulfuric acid is found to catalyze efficiently the condensation of o-phenylenediamines with various linear and cyclic ketones to afford the corresponding 1,5-benzodiazepines in quantitative yields under solvent-free conditions at room temperature

Phosphoglyceride phosphorus is readily determined directly on silica gel removed from thin-layer chromatograms, without elution, by a nondigestive procedure with a sulfuric-periodic acid reagent. The method is specific for hydrolyzable phosphoglyceride containing two acid-hydrolyzable groups. Cariolipin reacts only partially, while sphingomyelin, diether lecithin, and phosphonate cephalin fail ...

Phosphoglyceride phosphorus is readily determined directly on silica gel removed from thin-layer chromatograms, without elution, by a nondigestive procedure with a sulfuric-periodic acid reagent. The method is specific for hydrolyzable phosphoglyceride containing two acid-hydrolyzable groups. Cariolipin reacts only partially, while sphingomyelin, diether lecithin, and phosphonate cephalin fail ...

Frozen tissue sections were applied directly to silica gel plates, and the lipids were separated by developing the plates in different solvent systems. Quantitation of the lipid classes was achieved by direct transmission densitometry after the plates were treated with a chromic acid-sulfuric acid spray.

Halloysite (HNT) is treated with sulfuric acid and the physico-chemical properties of its morphology, surface activity, physical and chemical properties have been investigated when HNT is exposed to sulfuric acid with treatment periods of 1 h (H1), 3 h (H3), 8 h (H8), and 21 h (H21). The significance of this and similar work lies in the importance of using HNT as a functional material in nanoco...

Surface treatment of silica fume with sulfuric acid prior to incorporation in a cement matrix resulted in composites exhibiting increases in tensile strength by 12%, tensile modulus by 72%, tensile ductility by 57%, abrasion resistance by 20%, loss tangent by 30–80%, flexural storage modulus by 80–120%, and flexural loss modulus by 160–300%, relative to the values obtained by using as-received ...