Cyanide-functionalized mesoporous silica SBA-15 (CN/SBA-15) with pore diameters larger than 6 nm has been prepared by a one-pot synthesis. The structure of CN/SBA-15 is affected by the amount of the functional silane 2-cyanoethyltriethoxysilane (CTES) and the conditions of co-condensation in the acidic aqueous solution of the triblock copolymer Pluronic P123: whereas direct mixing of the silica...

a convenient, rapid, and one-pot method for the synthesis of azo dyes has been developed. in this protocol, diazotization reagent (arn2+ -cro3–sio2) was prepared via grinding of aromatic amines, nano2, wet sio2 and nano silica chromic acid (nano-sca) without solvent at room temperature. the obtained diazotization reagent was sufficiently stable to be kept at room temperature in the dry state fo...

OBJECTIVES To assess the bonding potential of a universal composite resin cement and an adhesive/composite system to differently pre-treated PEEK surfaces. METHODS One hundred and fifty PEEK disks were embedded in epoxy resin, polished (P4000 grit) and treated as follows (n=30/group): (A) no treatment, (B) acid etching with sulfuric acid (98%) for 1 min, (C) sandblasting for 10s with 50 micro...

Via the one-pot condensation reaction of ethyl acetoacetate, aromatic aldehydes, 2,4-dinitrophenylhydrazine, and β-naphthol; new pyrazolone derivatives were synthesized in the presence of three Brønsted acid catalysts. These Brønsted acid catalysts are Silica sulfuric acid (SSA), tetra-n-butyl ammonium hydrogen sulfate (TBAHSO4) and [2,2′-Bipyridine]-1,1′-diium tricyanomethanide {[2,2′-BPyH][C(...

A convenient and efficient methodology for the synthesis of densely substituted pyrrole-fused isocoumarins, which employs solid-supported silica sulfuric acid (SSA) as catalyst, has been developed. When the mixture of ninhydrin adducts of acetylacetone/ethyl acetoacetate and primary amines was heated on the solid surface of SSA under solvent-free conditions, the pyrrole-fused isocoumarins were ...

the effects of adding nano-silica particles on the compressive strength and water permeability of concrete and its comparison with that of micro-silica were investigated in this work. the effect of combination of nano- silica and micro-silica were also studied in this work, which resulted in an increase in compressive strength of concrete in comparison with other concrete specimens tested in th...

Introduction: Geologic evidence indicates that the K/T mass extinction occurred on 65 million years ago is caused by an asteroid or comet impact [e. g., 1]. However, the actual mechanism that caused the mass extinction is still very controversial. The impact generated sulfuric oxides are thought to cause an environmental perturbation and it is one of the most plausible hypotheses of the K/T kil...

Esterification reactions of some polyols and diols were investigated in the presence of SnO2 and nano-SnO2 and the results were compared with the catalyst-free conditions. High conversions were obtained for most of the reactions in the presence of SnO2 and nano-SnO2 which shows the high catalytic activity of SnO2 and nano-SnO2</sub...

In this work, polyamide (PA)/silica nanocomposite films prepared by dissolution method of composite mixing were investigated. The morphology of nanocomposite films were characterized using scanning electron microscope (SEM), reveals that nano silica powder were uniformly dispersed on PA silica nanocomposite film. Chemical composition of film was confirmed by Fourier transform infrared spectrosc...

Recent ab initio calculations showed that amines can enhance atmospheric sulfuric acid-water nucleation more effectively than ammonia, and this prediction has been substantiated in laboratory measurements. Laboratory studies have also shown that amines can effectively displace ammonia in several types of ammonium clusters. However, the roles of amines in cluster formation and growth at a micros...