王先飞,钱刚.芳构化法合成2,5-二羟基对苯二甲酸反应机理的密度泛函理论研究[J].分子催化,2024,38(3):234-244
芳构化法合成2,5-二羟基对苯二甲酸反应机理的密度泛函理论研究
A Density Functional Theory Study on the Reaction Mechanism for Synthesis of 2,5-Dihydroxyterephthalic Acid by Aromatization
投稿时间:2024-01-18  修订日期:2024-02-27
DOI:10.16084/j.issn1001-3555.2024.03.005
中文关键词:  2,5-二羟基对苯二甲酸  DFT  互变异构  芳构化  反应机理
英文关键词:2,5-dihydroxyterephthalic acid  DFT  keto-enol isomerization  aromatization reaction  reaction mechanism
基金项目:国家自然科学基金资助项目(21991104)(The National Natural Science Foundation of China (21991104)).
作者单位E-mail
王先飞 华东理工大学 化工学院, 上海200237  
钱刚 华东理工大学 化工学院, 上海200237 carlqg@ecust.edu.cn 
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中文摘要:
      采用密度泛函理论(DFT)计算, 研究了由1,4-环己二酮-2,5-二甲酸二甲酯(DMSS)制备2,5-二羟基对苯二甲酸(DHTA)的反应机理. 其中, 采用IEFPCM溶剂模型着重计算了DMSS由酮式互变异构为烯醇式的溶剂效应, 并探究了碘在催化DMSS烯醇式氧化芳构化过程中的作用机制. 计算结果表明, 在溶剂分子的辅助下, DMSS酮-烯醇式互变异构反应的能垒显著降低; 芳构化过程中, 碘首先与过氧化氢反应生成活性物质次碘酸, 其催化DMSS烯醇式发生碘代反应, 并经过后续的消去和互变异构生成2,5-二羟基对苯二甲酸二甲酯(DMDHT), DMDHT进一步水解生成DHTA. 同时, 通过核磁共振氢谱测试验证了DMSS酮-烯醇式互变异构的溶剂效应; 反应性能考评实验结果表明, 相较于无催化剂, 在碘的催化作用下, DMDHT产品的纯度和收率更高.
英文摘要:
      Using density functional theory (DFT) calculations, the reaction mechanism of the preparation of 2,5-dihydroxyterephthalic acid (DHTA) from 1,4-cyclohexanedione-2,5-dimethyl ester (DMSS) was investigated. Specifically, the solvent effect on the transformation of DMSS from its ketone form to enol form was emphasized using the IEFPCM solvent model, and the role of iodine in catalyzing the aromatization of DMSS enol form was explored. The computational results show that the energy barrier for the isomerization reaction between DMSS ketone and enol forms is significantly reduced with the assistance of solvent molecules. During the aromatization process, iodine first reacts with hydrogen peroxide to generate the active species iodic acid, which catalyzes the iodination reaction of DMSS enol form. Then the intermediates undergo subsequent elimination and interconversion to generate 2,5-dimethyl-1,4-benzenedicarboxylic acid dimethyl ester (DMDHT), further hydrolyzed to DHTA. Meanwhile, the solvent effects on the interconversion between DMSS ketone and enol forms were verified through nuclear magnetic resonance hydrogen spectrum testing, and the performance evaluation tests show that the purity and yield of DMDHT products from the iodine-catalyzed reaction are higher than those from the uncatalyzed reaction.
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