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STABILITY constants, IONIC strength, PERMITTIVITY, OXIDATION kinetics, and HYDROCHLORIC acid

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. [ABSTRACT FROM AUTHOR]

EXTRACTION techniques, ALKYLAMINES, and HYDROXYL group

The immediacy of the problem under study is due to the lack of data on the kinetics of polymer carrier impregnation with extraction agents. The article is aimed at obtaining the kinetic characteristics of the impregnation of a polymeric macroporous carrier--a weakly acidic cation resin with carboxyl groups--with trialkylamine and its solutions in acetone. The integral kinetic curves of the extraction agent adsorption on the carrier were obtained. This allowed estimating the time of equilibrium by the limited solution volume method. This time was 25-30 hours, decreasing with the application of a dilution agent and with the increase in temperature. The kinetic impregnation characteristics were calculated by means of the pseudo-second-order, Elovich, and internal diffusion models. The pseudo-second-order model describes the experimental kinetic data with a high correlation degree (R2 0.995-0.997) and points out that interaction with two sorption centres possibly takes place with the adsorption of a single trialkylamine molecule. The impregnation rate constants via an extraction agent were calculated using all kinetic models. Based on the apparent activation energy magnitude (37±14 kJ/mol), it can be assumed that diffusion is the rate-limiting step of the impregnation process. This article can be useful for creating impregnates containing extraction agents of various classes. [ABSTRACT FROM AUTHOR]