The aryl-(Z)-N-[2-amino-1,2-dicyanovinyl]formamidine 2 cyclize in solvent-free conditions and in the presence of a base to give a 5-amino-1-aryl-4-cyanoimidazoles 3. Silica sulfuric acid as an efficient and reusable heterogeneous catalyst has been used for the preparation of amidines 2 from formimidate 1 through reaction with aromatic amines at room temperature and in good to excellent yields. ...

In this paper, the corrosion behavior of the filled epoxy paint with the rice husk ash RHA on steel substrates in two different corrosive environments natural sea water and 2M sulfuric acid has been studied. Electrochemical impedance spectroscopy EIS was used to evaluate protective properties of different organic coating systems due to the different filler composition. RHA was prepared by heati...

Silica nanoparticles were synthesized by chemical methods from tetraethylorthosilicate (TEOS), polyethylene glycol 5% and hydrochloric acid 0.001 N. The sol-gel process was applied for the preparation of nano silica gel. This method is hydrolysis and condensation reactions of TEOS as precursor of silica. The optimal synthesis conditions for the preparation of silica nanoparticles were obtained ...

An attempt was made to control the surface charge of colloidal silica nanoparticles with 20 nm and 100 nm diameters. Untreated silica nanoparticles were determined to be highly negatively charged and have stable hydrodynamic sizes in a wide pH range. To change the surface to a positively charged form, various coating agents, such as amine containing molecules, multivalent metal cation, or amino...

A new method for the production of boron nanoparticles is described. Boron trichloride is dissociated through injection into thermal plasma followed by a nucleation process producing boron nanoparticles. The ambient oxidation of the as-produced nanoparticles is also investigated. The nanoparticles were characterized with scanning transmission electron microscopy, electron energy loss spectrosco...

An improved synthesis of multifunctionalized pyrrolo[2,3,4-kl]acridine derivatives with different substituted patterns using silica sulfuric acid (SSA) as a heterogeneous catalyst under microwave irradiation conditions was developed. The reaction could be conducted by using readily available and inexpensive substrates within short periods of 12-15 min. under microwave irradiation. Compared with...

Nanocomposite cation exchange membranes (CEMs) were prepared by adding various amounts of functionalized silica-coated magnetite nanoparticles to the sulfonated polyethersulfone (sPES) polymeric matrix. The particles were synthesized first by the co-precipitation method (M0). Different surface modifications were then carried out on them by grafting three functional groups of mercaptopropyl, pro...

In this study, we have performed nanoscale characterization of Si-clusters and Si-nanowires with a laser-assisted tomographic atom probe. Intrinsic and p-type silicon nanowires (SiNWs) are elaborated by chemical vapor deposition method using gold as catalyst, silane as silicon precursor, and diborane as dopant reactant. The concentration and distribution of impurity (gold) and dopant (boron) in...