理论计算与实验结合的物理化学实验综合设计
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摘要
在物理化学实验"乙酸乙酯皂化反应速率常数的测定"的基础上,设计增加理论计算内容,即用GaussView 5. 0构建反应物、过渡态中间体的模型,然后用Gaussian 09W算出反应物总能量和中间体能量,进而算出反应活化能;实验测定是用电导率仪测量反应进程中体系电导随时间、温度的变化,利用实验数据求得反应速率常数和活化能;最后将两种方法所得的活化能进行对比。该设计探讨了将实验与理论结合的可行性及实施性,有助于形成实验测定和理论计算相结合的综合化学实验新模式。通过实验,学生既可锻炼实验技能又能掌握相关计算软件的使用,在分子水平上理解化学反应机理,充分调动学生的积极性,提高学生的综合实验能力。
On the basis of the determination of the rate constant of ethyl acetate saponification reaction,theoretical calculation is added. The models of the reactants and intermediate are constructed by using GaussView 5. 0,then the energies of reactants and intermediate are calculated by Gaussian 09 W,finally the activation energy is calculated. The experimental measurement is mainly to monitor the change of the system conductivity with time and temperature in the process of saponification by the conductivity meter. The reaction rate constant and activation energy are obtained by experimental data. At the end,the activation energies obtained by the two methods are compared. The design explores the feasibility and implementation of combining experiment with theory,and helps to form a new comprehensive chemical experiment mode combining experimental measurement with theoretical calculation. Through this experiment,students not only exercise their ability to operate,but also mastered the use of computing software,understand the mechanism of chemical reaction at the molecular level,their enthusiasm is stimulated to participate in experiments,and their comprehensive experimental skills are improved.
On the basis of the determination of the rate constant of ethyl acetate saponification reaction,theoretical calculation is added. The models of the reactants and intermediate are constructed by using GaussView 5. 0,then the energies of reactants and intermediate are calculated by Gaussian 09 W,finally the activation energy is calculated. The experimental measurement is mainly to monitor the change of the system conductivity with time and temperature in the process of saponification by the conductivity meter. The reaction rate constant and activation energy are obtained by experimental data. At the end,the activation energies obtained by the two methods are compared. The design explores the feasibility and implementation of combining experiment with theory,and helps to form a new comprehensive chemical experiment mode combining experimental measurement with theoretical calculation. Through this experiment,students not only exercise their ability to operate,but also mastered the use of computing software,understand the mechanism of chemical reaction at the molecular level,their enthusiasm is stimulated to participate in experiments,and their comprehensive experimental skills are improved.
引文
[1]方维海.计算驱动的合成化学:无金属合成4—取代吡啶的新方法[J].物理化学学报,2017,33(4):645-646.
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[7]陈书鸿,张丽莹,乐艳,等.乙酸乙酯皂化反应速率常数测定实验的改进[J].重庆三峡学院学报,2016(32):61-64.
[8]刘振.乙酸乙酯皂化反应速率常数测定实验改进[J].西安文理学院学报,2015,18(2):17-19.
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[2]王溢磊.甲醛分子的结构和性质的计算化学研究—介绍一个计算化学实验[J].大学化学,2014,29(5):66-70.
[3]徐香兰,王翔.在结构化学教学中增设量子化学计算实验课的探索[J].大学化学,2018,33(2):22-28.
[4]苏培峰,谭凯,吴安安,等.理论与计算化学研究进展[J].厦门大学学报,2011,50(2):311-318.
[5]何荣幸,黄成,彭敬东.物理化学实验教学改革中的创新教育思路[J].西南师范大学学报,2012,37(4):186-189.
[6]任庆云,杨晓磊,王松涛.“乙酸乙酯皂化反应速率常数测定”实验数据处理程序的开发[J].广州化工,2014,42(13):199-201.
[7]陈书鸿,张丽莹,乐艳,等.乙酸乙酯皂化反应速率常数测定实验的改进[J].重庆三峡学院学报,2016(32):61-64.
[8]刘振.乙酸乙酯皂化反应速率常数测定实验改进[J].西安文理学院学报,2015,18(2):17-19.
[9]马志广,庞秀言.物性参数与测定[M].北京:化学工业出版社,2009.
[10]田亚利,张聪杰. Gauss View软件在分子和晶体结构模拟中的使用探究[J].化学教学,2015(6):90-93.
[11] Frisch M J,Trucks G W,Schlegel H B,et al. Gaussian 09[M].Wallingford CT:Gaussian Inc,2009.
[12]曹楠.测定乙酸乙酯皂化反应速率常数的原理和方法[J].枣庄师专学报,2000,17(2):60-63.
[13]马军营.羧酸酯水解的类型及影响因素[J].信阳师范学院学报,1998,11(4):417-421.
[14] KA Gingerich,UV Choudary,K Krishnan. Thermochemical study of the molecule BaC2[J]. Journal of Chemical Physics,1985,83(3):1237-1239.
[15] Poulin N M,Bramley M J,Carrington T,et al. Calculation of vibrational(J=0)excitation energies and band intensities of formaldehyde using the recursive residue generation method[J]. J Chem Phys,1996,104(20):7807.