S EVERAL parameters have been studied in this manuscript to investigate the effect of certain conditions on the removal and the decolorization of the textile dyes: reactive yellow 14 (RY 14) and reactive green (RG) dyes from aqueous solution. Parameters such as temperature, initial concentration of dye and initial pH were taken into consideration to reach the perfect removal and decolorization for both dyes. This work was achieved in both dark and photoreaction processes. In dark reaction, the type of adsorption was determined based on Gibb's free energy values, activation energies and change in enthalpies, which were found that the physical adsorption for removal of both dyes is predominated, and the reaction is exothermic. The adsorption capacity and percentage of removal both dyes elevated with raised the dye concentration. The best initial pH for removal of RY 14 and RG dyes dyes was conducted and found equal to 5.14 and 9.75 respectively. The raised in temperature is not enhanced the adsorption process, that due to the dark reaction for both dye is exothermic. The small negative values of change in entropies are proved the associative mechanism of both dyes on ZnO surface. On the other hand, the results under the percent UV-light showed, that the optimal conditions were found at 303.15 K, with 25 ppm and optimum pH=11.01 for reactive green(RG) dye, while the optimum conditions were appearing at 50 ppm and best pH= 6.075 for reactive yellow 14 at same temperature. The decolorization process for both studied dyes was found to be a pseudo-first-order kinetic, fast (low activation energies), endothermic reaction (positive change in enthalpies), non-spontaneous (positive change Gibbs free energies) and less random (negative change in entropies). The photoreaction is a completed to removal process to depress the toxicity for these studied textiles dyes.
A COPOLYMERS are important compounds today because of their wide applications in various industrial and medical fields and in other fields. Therefore, the study of preparing many of these polymers has been studied. This research involved preparing linear polyester contain Schiff-base unit by interfacial polycondensation three type diacid chloride (Succinoyl Chloride, Adipoyl Chloride and sebacoyl Chloride) in a chloroform /water system employing phase transfer catalyst with monomer containing two hydroxyl which is derived from a 4-hydroxy aniline reacted with a 4-hydroxy benzaldehyde monomer. The monomer (EM1) and polyester (EM2, EM3, and EM4) were characterized by FTIR, 1 H NMR, 13 C NMR and TGA analysis. The polyester-Schiff base so obtained show good thermal stability.
The kinetics of oxidation of diethyl ether (DE) with sodium N-chloro-p-toluenesulphonamide (CAT) in hydrochloric acid solution has been studied at (313°K).The reaction rate show a first order dependence on [CAT] and fractional order dependence on each [DE] and [H+] .The variation of ionic strength of the medium has no significant effect on the reaction rate , addition of p-toluenesulphonamide (p-TSA) affects the reaction rate marginally the rate increased with decreasing dielectric constant of the medium , the stochiometry of the reaction was found to be 1:2 and oxidation products were identified , A Michaelis – Menten type mechanism has been suggested to explain the results.The equilibrium and the decomposition constants of CAT – diethyl ether complex have been evaluated. Thermodynamic parameters were computed by studying reaction at temperatures range ( 308 – 323°K) for the rate limiting step and for the observed first order constants by the linear Arrhenius plot. The mechanism proposed and the derived rate law are consistent with observed kinetics.
The kinetics of chlorination of N-acetylglycin (AG) with sodium Nchloro-p-toluene sulphonamide (CAT) in presence of HCL has been studied at 318 o K. The reaction rate shows afirst-order dependence each on [CAT] and [H + ] and zero order dependence on [AG]. The Variation of ionic strength of the medium or chloride ion had no significant effect on the reaction rate. Addition of P-TSA is marginally affected the reaction rate. The rate increase with decreasing dielectric constant of the medium. The stiochiometry of the reaction was found 1:1 and the oxidation producte were identified. The thermodynamic parameters were computed. The mechanism proposed and the derived rate law were in agreement with the observed kinetics. INTRODUCTION
The kinetics of tetrahydrofuran oxidation by sodium N-chloro-p-toluene sulfonamide in the hydrochloric acid medium was studied in this work at 308 K. The reaction rate shows a first-order dependence on [CAT] and fractional-order dependence each on [THF] and [H+]. The derivative rate law, which suitable for experimental results, is Equation 24. The first-order rate constant has been evaluated from the relationship of the plot of Log [CAT] versus Time. The variation of the ionic strength by the addition of sodium perchlorate (NaClO4) and chloride ion on the medium showed no significant effect on the reaction. The reaction rate raised with decreasing dielectric constant (D), while the addition of p-toluene sulfonamide retards the rate of reaction. The oxidation reaction of tetrahydrofuran have been studied at a different temperature, The equilibrium constants for the formation of hypochlorous acid, protonated hydrochlorous acid and protonated hydrochlorous acid–THF complex and its decomposition constant have been estimated. Also, the rate constant for the slow (rate-determining step) and the activation parameter have been calculated. A suitable mechanism for the oxidation reaction of tetrahydrofuran was proposed based on the experimental finding. The mechanism includes the reaction of active species (H2OCl) of the oxidizing agent with the tetrahydrofuran in a fast step to give the complex(X). This complex will then transformed into complex (X̅ ) in slow step then to γ-butyrolactone in another fast step.
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