the aim of this paper is to study the kinetic study carbonylation of methanol using of the homogeneous rhodium catalyst and ch3i as the promoter in acid media based on monsanto process. the reaction was carried out in liquid media in the constant pressures 20,28 and 40 atm. and temperatures 170 to185oc, espect to the  initial  reactant concentrations and co pressure.  it was identified that the...

the kinetics of old corrugated container (occ) soda-oxygen delignification was investigated. three delignification temperatures (145,165 and 175ºc) were applied. the pulping duration was adjusted at 150 minutes and the measurements were conducted at 10 minutes intervals. the pulping consistency, oxygen pressure and active alkali were constant at 10%, 6 bar and 18% naoh respectively in all pulpi...

The formation of Compounds I, II, and III of hog thyroid peroxidase was demonstrated in its reaction with H2O2 by spectrophotometric and kinetic methods combined with a stopped flow technique. Hog thyroid peroxidase reacted with H2O2 to form Compound I with a rate constant of 5.2 X 10(6) M-1 s-1. Compound I was then spontaneously converted to Compound II with a rate constant of 8 s-1. In the pr...

The rate constant for the NCN + NO 2 reaction has been measured by a laser photolysis/laser-induced fluorescence technique in the temperature range of 260-296 K at pressures between 100 and 500 Torr with He and N 2 as buffer gases. The NCN radical was produced from the photolysis of NCN 3 at 193 nm and monitored by laser-induced fluorescence with a dye laser at 329.01 nm. The rate constant was ...

A simple mathematical model of steady state  oxygen distribution subject to diffusive transport and non- linear uptake in a retinal cylinder has been developed. The approximate analytical solution to a reaction- diffusion equation are obtained by using series expansions. The computational results for the scaled variables are presented through graphs. The effect of the important parameters (1) d...

The spontaneous and pepsin-catalyzed activation of pepsinogen has been observed and analyzed kinetically. At appropriate protein concentrations (1 mg per ml or less), a kinetically first order reaction was observed in the pH range 1 to 3, implying an intramolecular activation mechanism. Substantiation of the first order reaction came from a linear plot of log pepsinogen concentration versus tim...

The pairing of single- and double-stranded DNA molecules at homologous sequences promoted by recA and single-stranded DNA-binding proteins of Escherichia coli follows apparent first-order kinetics. The initial rate and first-order rate constant for the reaction are maximal at approximately 1 recA protein/3 and 1 single-stranded DNA-binding protein/8 nucleotides of single-stranded DNA. The initi...

the catalytic oxidation of toluene to benzoic acid in the liquid phase has been studied in an un-stirred tank reactor. low concentration of acetic acid was added in order to increase the solubility of the catalyst in toluene. the dependence of the rate of reaction on the concentration of toluene catalyst and oxygen pressure was studied. it has been suggested that liquid phase oxidation of tolue...

The pH dependence study reveals that the Cys 206 sulphydryl group of bovine carbonicanhydrase in the native form is not exposed. During the reaction of 2,2'-dithiobispyridine (2-DTP) with the enzyme, there was no absorbance change recorded. In the presence ofsurfactants, the pH dependence profiles of the apparent second order rate constants, kapp, forthe reaction of 2-DTP with bovine carbonic a...