Analysis on the Application Conditions of the Pre-Equilibrium and Steady-State Approximations

Sun Ying, Zhang Shuyong,

Abstract

The application conditions of pre-equilibrium and steady-state approximations usually used for treatment of complex chemical kinetics are discussed. Based on the characters of opposing reaction, the simplified application conditions for pre-equilibrium approximation is proposed. The shortcoming of the former conditions is pointed out. By defining a dimensionless parameter relating to the discrepancy from steady state and using graphic method, the application conditions of steady-state approximation for the consecutive reaction is clarified. When the rate for consumption of the intermediate is 100 times larger than its generation rate, the error by using steady-state approximation is less than 1%, which is a good approximation.

Keywords： Approximation treatment ; Pre-equilibrium approximation ; Steady-state approximation ; Consecutive reaction ; Graphic method

Sun Ying. Analysis on the Application Conditions of the Pre-Equilibrium and Steady-State Approximations. University Chemistry[J], 2021, 36(2): 2002076-0 doi:10.3866/PKU.DXHX202002076

1 引言

$\rm{A}\underset{{k}_{-1}}{\overset{{k}_{1}}{\rightleftharpoons }}\rm{C}$

${\rm{C}} + {\rm{B}}\xrightarrow{{{k_2}}}{\rm{P}}$

$D = \frac{{1 - {{\rm{e}}^{\left( {1 - 1/k_2^*} \right)\Delta {t^*}^\prime }}}}{{k_2^*{{\rm{e}}^{\left( {1 - 1/k_2^*} \right)\Delta {t^*}^\prime }} - 1}}$

参考文献 原文顺序 文献年度倒序 文中引用次数倒序 被引期刊影响因子

Volk L. ; Richardson W. ; Lau K. H. ; Hall M. ; Lin S. H. J. Chem. Educ. 1977, (54) (2), 95.

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