共查询到19条相似文献,搜索用时 187 毫秒
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模拟热谱曲线法(Ⅲ)——可逆反应 总被引:2,自引:2,他引:2
可逆反应是一类重要的复合反应,建立其相应的热动力学研究法有重要意义.刘劲松等[1]建立了可逆反应热动力学的对比进度研究法,曾宪诚等[2]建立了二种可逆反应热动力学无量纲参数研究法.本文根据热动力学理论和文献[3]的基本原理,建立了热导式量热体系的几类(2-2型、2-1型、1-2型)可逆反应通用的模拟热谱曲线研究法.该法无需标定热动力学体系的冷却常数,直接从一张热谱图上同时解析出可逆反应的kf、kb、K,方法更为简便,实用性强,在化学、生化反应的热动力学研究中具有广泛的应用前景.应用该法在15℃、25℃下研究了硝基乙烷… 相似文献
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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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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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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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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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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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Introduction Arginase (EC 3.5.3.1) is a widespread and very im-portant enzyme in mammals, which specifically cata-lyzes the hydrolysis of L-arginine to urea and the non-protein amino acid L-ornithine, a key step in the urea cycle.1 Urea is the principal metabolite for disposal of nitrogen as a neutral and nontoxic waste product formed during amino acid metabolism in mammals. L-ornithine serves as a biosynthetic precursor to L-proline and the polyamines such as putrescine, sper-mine (in eucar… 相似文献