共查询到17条相似文献,搜索用时 78 毫秒
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根据化学反应动力学和热动力学基本理论, 建立了简单级数反应的热动力学对比参量方程, 提出了一种新的热动力学研究法--对比参量法. 利用该法可以从一张热谱图上同时解析出化学反应的速率常数、半衰期和热动力学体系的冷却常数. 实验结果验证了方法的正确性. 相似文献
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Characteristic parameter method for studying kinetics of opposing reactions in calorimeter 总被引:1,自引:0,他引:1
According to the theoretical basis of thermokinetics, the integral and differential thermokinetic equations of opposing reactions have been derived, and a novel thermokinetic research method, the characteristic parameter method for opposing reactions which taking place in a batch conduction calorimeter under isothermal condition, has been proposed in this paper. Only needing the characteristic thermoanalytical data corresponding to tm and 2tm from the same curve, the rate constants of forward and backward reactions and equilibrium constant can be calculated simultaneously with this method. In order to test the validity of this method, the proton-transfer reactions of nitroethane with ammonia at 15 and 25°C, and with trihydroxymethyl aminomethane (Tris) at 15 and 30°C have been studied, respectively. The results of rate constants and equilibrium constants calculated with this method are in agreement with those in the literature. Therefore, the characteristic parameter method for opposing reaction is believed to be correct.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
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Y.-Q. Zhang X.-C. Zeng Y. Chen X.-G. Meng A.-M. Tian 《Journal of Thermal Analysis and Calorimetry》1999,58(2):463-475
On the basis of the theory of thermokinetics proposed in the literature, a novel thermokinetic method for determination of the reaction rate, the characteristic parameter method, is proposed in this paper. Mathematical models were established to determine the kinetic parameters and rate constants. In order to test the validity of this method, the saponifications of ethyl benzoate, ethyl acetate and ethyl propionate, and the formation of hexamethylenetetramine were studied with this method. The rate constants calculated with this method are in agreement with those in the literature, and the characteristic parameter method is therefore believed to be correct.In the light of the characteristic parameter method, we have developed further two thermo-kinetic methods, the thermoanalytical single and multi-curve methods, which are convenient for simultaneous determination of the reaction order and the rate constant. The reaction orders and rate constants of the saponifications of ethyl acetate and ethyl butyrate and the ring-opening reaction of epichlorohydrin with hydrobromic acid were determined with these methods, and their validity was verified by the experimental results.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
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Chen Y. Xie J. Q. Zhang B. Zeng X. C. 《Journal of Thermal Analysis and Calorimetry》2004,75(3):847-855
A novel thermokinetic research method for determination of rate constants of simple-order reaction in batch conduction calorimeter
under isothermal condition, the characteristic parameter method, is proposed in this paper. Only needing the characteristic
time parameter tm obtained from the measured thermoanalytical curve, the kinetic parameters of reactions studied can be calculated
conveniently with this method. The saponifications of ethyl propionate and ethyl acetate in aqueous ethanol solvent, the polymerization
of acrylamide in aqueous solution, the ring opening reaction of epichlorohydrin with hydrobromic acid have been studied. The
experimental results indicate that the characteristic parameter method for simple-order reaction is correct.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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Chen Y. Wang H. D. Meng X. G. Zeng X. C. Xie J. Q. 《Journal of Thermal Analysis and Calorimetry》2000,61(1):219-228
A novel thermokinetic research method for determination of the rate constant of a reaction taking place in a batch conduction
calorimeter under isothermal conditions is proposed: the double-thermoanalytical curve method. The method needs only the characteristic
time parameter t
m, the peak height Δm at time t
m and the peak area a*m after time t
m for two thermoanalytical curves measured with different initial concentrations of the reactants: it conveniently calculates
the rate constants. The thermokinetics of four reaction systems were studied with this method, and its validity was verified
by the experimental results.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Fotis P. Rigas 《国际化学动力学杂志》2021,53(1):7-15
The determination of rate constants for consecutive irreversible reactions is a difficult and time‐consuming problem, especially when the research extends up to many subsequent products. Thus, the derivation of proper mathematical expressions would greatly facilitate the determination of these rate constants when only the rate constant of the first consecutive reaction is known. Many authors have dealt with this problem in the past but the issue is still of interest to the scientific community judging from recent publications. This paper aims at extending our knowledge of mathematical expressions for rate constant ratios of consecutive reactions to more than three reactions, as is the situation now, and offering a simple graphical estimation of the rate constant ratios exploiting the maxima of each intermediate product. Furthermore, the method extends to the derivation of a generic formula for the estimation of the rate constant ratios based on this graphical approach. This approach for the estimation of rate constant ratios based on mathematical expressions and graphical estimations was validated against experimental data found in the literature. 相似文献
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Cheng S.-Q. Huang Z. Meng X.-G. Zeng X.-C. 《Journal of Thermal Analysis and Calorimetry》2000,63(2):415-421
This paper presents a novel data processing method for thermokinetics of faster first-order reaction on the basis of the double-parameter
theoretical model of a conduction calorimeter, in which the rate constant of a first-order reaction can be calculated from
only four peak height data from the same thermoanalytical curve without using any peak-area. The saponifications of ethyl
acetate and methyl acetate in aqueous solution and ethyl benzoate in aqueous alcohol have been studied to test the validity
of this method. The rate constants calculated with this method are in fair agreement with those in literature; hence the validity
of this method is demonstrated.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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Sreehari Sastry Sreeramakavacham B. Gowri Sankara Rao K. Mallika T. Vindhya Kumari S. Lakshminarayana Sie Tiong Ha 《Liquid crystals》2013,40(3):384-390
A novel method for temperature dependence of order parameter calculations at different wavelengths through birefringence measurements for ferroelectric liquid crystals (S)-(-)-2-methylbutyl 4′-(4″-n-alkanoyloxy benzoyloxy) biphenyl-4-carboxylates (where n?=?16 and 18) has been proposed using image analysis and linear regression method of Kuczynski equation. Measurements are made for its liquid crystal phases (SmecticC*, SmecticA) to the isotropic phase of the sample. The birefringence values of the samples at different wavelengths are obtained from the textural analysis of liquid crystal as a function of temperature using MATLAB software. 相似文献