普鲁士蓝类似物合成过程及其配体改性的热力学研究

发布时间：2019-03-22 18:18

【摘要】：量热法属于非特异性的研究方法,即只要一个过程包含了热量的变化都可以利用量热仪进行研究,而且等温滴定量热仪能够连续记录研究过程的热信号,因此等温滴定量热技术受到了人们越来越多的关注。为了从热力学角度探讨影响普鲁士蓝类似物催化性能的因素,本论文利用TAM2277型量热仪对七种普鲁士蓝类似物(PBA)的合成过程以及基于铁钴普鲁士蓝类似物(FeCoPBA)的改性过程的热力学性质进行了研究。具体内容如下:1、首先分别合成并表征了七种常用的PBA(Fe Co PBA、Cu CoPBA、Ni CoPBA、ZnCoPBA、CdCoPBA、CoCo PBA和MnCo PBA),再将这七种PBA分别催化苯乙烯环氧化反应,然后利用等温滴定量热技术分别对这七种PBA形成过程的热力学性质进行了研究。结果表明这七种PBA的合成过程都是放热的自发过程,其中ZnCoPBA的合成过程是焓熵共同驱动的,FeCo PBA、CuCo PBA、NiCo PBA、CdCoPBA、CoCoPBA五种PBA的合成过程都是焓驱动的,而Mn Co PBA的生长过程较为特殊,不能用单结合位点模型进行拟合。对比六种PBA的尺寸、催化效果以及形成过程的热力学参数,我们发现颗粒尺寸最小、催化效果最好的Cu CoPBA形成过程的焓变和吉布斯自由能变量最小,而颗粒尺寸最大、催化效果最差的ZnCoPBA形成过程的焓变和吉布斯自由能变量最大。2、其次利用CsCl或RbCl对FeCoPBA进行了改性,再将改性后的FeCo PBA催化苯乙烯环氧化反应,并利用等温滴定量热技术研究了CsCl或RbCl对FeCo PBA改性过程的热力学性质。结果表明CsCl或RbCl改性Fe Co PBA的过程都是放热的、焓驱动的自发过程;对比改性前后Fe Co PBA的尺寸、催化效果以及形成过程的热力学参数,我们发现Cs Cl或RbCl改性后FeCoPBA的尺寸减小;而且随着CsCl或者RbCl量的增加,FeCoPBA对苯乙烯环氧化反应的催化效果增强,形成过程的焓变和吉布斯自由能变量的值不断减小并趋于稳定。3、最后利用甲醇、乙醇、叔丁醇和N,N-二甲基甲酰胺(DMF)四种有机配体分别对FeCo PBA进行了改性,再将改性后的FeCo PBA催化苯乙烯环氧化反应,并利用等温滴定量热技术分别研究了四种有机配体改性FeCoPBA过程的热力学性质。结果表明甲醇、乙醇、叔丁醇改性FeCoPBA的合成过程是焓驱动的自发过程,而DMF改性Fe Co PBA的合成过程是熵焓共同驱动的自发过程。对比改性前后FeCo PBA的催化效果以及形成过程的热力学参数,我们发现与FeCo PBA结合作用最强的甲醇改性后的产物——FeCo PBA?甲醇的催化性能最差,而与FeCoPBA结合作用最弱的DMF改性后的产物——FeCoPBA?DMF的催化性能最好。
[Abstract]:Calorimetry is a non-specific research method, that is, only one process contains the change of heat can be studied by calorimeter, and the isothermal drop calorimeter can continuously record the thermal signal of the research process. Therefore, more and more attention has been paid to the isothermal droplet quantitative heat technology. In order to explore the factors affecting the catalytic performance of Prussian blue analogues from the thermodynamic point of view, In this paper, the synthesis process of seven Prussian blue analogues (PBA) and the thermodynamic properties of the modification process based on the iron cobalt Prussian blue analogue (FeCoPBA) were studied by means of TAM2277 calorimeter. The main contents are as follows: 1. Seven kinds of commonly used PBA (Fe CoPBA, Cu CoPBA,Ni CoPBA,ZnCoPBA,CdCoPBA,CoCo PBA and MnCo PBA), were synthesized and characterized, and then these seven PBA catalyzed epoxidation of styrene, respectively. The thermodynamic properties of these seven PBA formation processes were studied by isothermal drop quantitative heat technique. The results show that these seven PBA synthesis processes are exothermic spontaneous processes, in which the synthesis process of ZnCoPBA is driven by enthalpy and entropy, and the synthesis process of FeCo PBA,CuCo PBA,NiCo PBA,CdCoPBA,CoCoPBA five PBA is enthalpy driven. However, the growth process of Mn Co PBA was very special and could not be fitted by single binding site model. Compared with the size, catalytic effect and thermodynamic parameters of the formation process of six kinds of PBA, we found that the enthalpy change and Gibbs free energy variable of the Cu CoPBA formation process, which have the smallest particle size and the best catalytic effect, are the smallest, while the particle size is the largest. The enthalpy and Gibbs free energy of the formation process of ZnCoPBA with the worst catalytic effect were the largest. 2. Secondly, the FeCoPBA was modified by CsCl or RbCl, and then the modified FeCoPBA was used to catalyze the epoxidation of styrene. The thermodynamic properties of the modification of FeCo PBA by CsCl or RbCl were studied by isothermal drop quantitative thermal technique. The results show that the modification of Fe Co PBA by CsCl or RbCl is an exothermic, enthalpy-driven spontaneous process. Compared with the size of FeCoPBA before and after modification, the catalytic effect and the thermodynamic parameters of the formation process, we found that the size of FeCoPBA modified by Cs Cl or RbCl decreased. Moreover, with the increase of CsCl or RbCl content, the catalytic effect of FeCoPBA on epoxidation of styrene was enhanced, the enthalpy change and Gibbs free energy variable of the formation process decreased and tended to stabilize. 3. Finally, methanol, ethyl alcohol, tert-butanol and N, were used as the catalyst for epoxidation of styrene. Four organic ligands of N-dimethylformamide (DMF) were used to modify FeCo PBA, and then the modified FeCo PBA was used to catalyze the epoxidation of styrene. The thermodynamic properties of FeCoPBA modified by four kinds of organic ligands were studied by isothermal drop quantitative thermal technique. The results show that the synthesis of FeCoPBA modified by methanol, ethyl alcohol and tert-butyl alcohol is a spontaneous process driven by enthalpy, while the synthesis process of FeCoPBA modified by DMF is a spontaneous process driven by entropy enthalpy. Comparing the catalytic effect of FeCo PBA before and after modification as well as the thermodynamic parameters of the formation process, we found that FeCo PBA?, the product of methanol modification with the strongest binding to FeCo PBA, was found to be the product of methanol modification. The catalytic activity of methanol was the worst, while that of FeCoPBA?DMF, the product modified by DMF, which had the weakest binding to FeCoPBA, was the best.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36

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