a kinetic-spectrophotometric procedure is reported for determination of trace amounts of ag(i). this method is based on catalytic effect of silver ion on the oxidation of congo red by potassium peroxodisulphate at ph=3.4 and 30 oc in the presence of 1,10-phenanthroline as an activator. the reaction was followed spectrophotometrically by measuring the rate of change in absorbance of congo red at...

An aqueous solution of boric acid, as an efficient and green catalytic system, was efficiently utilized four-component cascade reaction of aryl aldehydes, dimedone, β-ketoesters and ammonium acetate to give hexahydroquinolines. By the reaction of boric acid with water, H+ was generated and efficiently catalyzed the reaction under mild and green condition. Also, optimization of the reaction cond...

a powerful and convenient reaction procedure for the c-n coupling reaction (the buchwald-hartwig reaction), yielding products of n-arylanilines and n-arylamines in both conventional heating and microwave irradiation has been reported. the protocol utilizes a stable and new supper ferromagnetic nanoparticle chelating n-heterocyclic dicarbene palladium(ii) complex (pd-nhc) as catalyst which helps...

so42-/zno-tio2 catalyst was prepared by sulfating zno-tio2 powders with h2so4 solution. the catalyst was characterized by xrd, ir and hammett indicator. the catalyst showed strong acidity(h0 ≦-16.0). the optimum conditions are found that the calcination temperature is 823k and the soaked consistency of h2so4 is 1 mol/dm3. then so42-/zno-tio2 was applied as the catalyst in the catalytic synthesi...

steam reforming is one of the most important processes for producing hydrogen from hydrocarbon fuels such as lpg and has attracted much attention due to its high efficiency and economy. in this study, the lpg steam reforming reaction was investigated on nickel catalysts supported on four various zeolites (h-y, na-y, hzsm5 and ferrierite). the catalytic tests were performed in a tubular fixed be...

this study describes a new simple, sensitive and selective catalytic kinetic spectrophotometricmethod for the determination of vanadium (v). the method is based upon the catalytic effect ofvanadium (v) on the oxidation of carminic acid by bromate in sulfuric acid media. the reaction wasfollowed spectrophotometrically by measuring the decrease in absorbance at 490 nm and thedependence of sensiti...

A kinetic-spectrophotometric procedure is reported for determination of trace amounts of Ag(I). This method is based on catalytic effect of silver ion on the oxidation of congo red by potassium peroxodisulphate at pH=3.4 and 30 oC in the presence of 1,10-phenanthroline as an activator. The reaction was followed spectrophotometrically by measuring the rate of change in absorbance ...

Ni/Al-HMS/HZSM-5 catalysts with varying amounts of Si/Al ratios were prepared via the impregnation method and evaluated for the hydrogenation of benzene at 130−190 °C. To study the catalyst characterization, various methods were used as X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, temperature-programmed des...

a novel rice-husk-silica supported n-propyl bipyridinium chloride (rhprbpcl) has been prepared. due to the basicity of rhprbpcl, it was decided to evaluate its catalytic activity in the one-pot preparation of tetrahydrobenzo[b]pyran, dihydropyrano[3,2-c]chromene and dihydropyrano[4,3-b]pyran derivatives. the catalyst was characterized by ft-ir, sem and tga analyses. this methodology offers seve...

To understand the effect of different thermal conductivities on catalytic combustion characteristics, effect of thermal conductivity on micro-combustion characteristics of hydrogen-air mixtures in Pt/γ-Al2O3 catalytic micro-combustors were investigated numerically with detailed chemical kinetics mechanisms. Three kinds of wall materials (100, 7.5, and 0.5 W/m·K) were selected to investigate the...