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...

This study is focused on synthesis of nano-colloidal silica via alkaline water glass solution. Sodium ions of water glass were removed by cation exchanging in a resin column to obtain the silicic acid which was titrated to the solution of sodium silicate. Concentration of the colloidal silica and pH value of the solutions were controlled using different concentrations of alkaline sodium silicat...

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...

β -Acetamido ketones are valuable building blocks for the preparation of β -amino ketones or β -amino alcohols such as the antibiotic nikkomycins [1] and neopolyoxines [2]. α-Acetamido ketones are obtained in the Dakin-West reaction [3] and β -acetamido ketones by the Iqbal route. In the latter, an aromatic aldehyde, an enolizable ketone and acetonitrile are condensed in the presence of acetyl ...

Geopolymers are a new promising binder manufactured by activation of a solid aluminosilicate source material with a highly alkaline activating solution and aided by heat. Fly ash, considered to be a waste material is rich in silica and alumina and hence can be used as a source material for manufacture of Geopolymers. These binders have been reported to achieve high early strength and better dur...

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 ...

Two simple protocols for the synthesis of tetrahydrobenzo[a]xanthenes-11-ones using nano silica phosphoric acid are reported. Short reaction times, high yields, reusability of catalyst and easy workup are some advantages of these protocols.

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 ...