Solvent effects on a Diels-Alder reaction in supercritical water: RISM-SCF study
Solvent effects on a Diels-Alder reaction in supercritical water: RISM-SCF study
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DOI：
10.1021/ja991673o
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发表时间：
2000-03-15
影响因子：
15
通讯作者：
Hirata, F
中科院分区：
文献类型：
--
作者：
Harano, Y;Sato, H;Hirata, F
用电子结构理论和液相理论相结合的方法研究了超临界水中Diels-Alder反应。目标体系是环戊二烯与甲基乙烯酮的环加成反应。计算了超临界水中的反应速率和产率，并与环境水中的反应速率和产率进行了比较。比较了顺式和反式两种异构体的激活自由能。结果与实验观察到的速率和收率的提高一致。在超临界水中，溶剂化对速率常数的影响减小，但由于热激发而不是溶剂化效应使速率增加。与顺式构象相比，反式构象在环境水和超临界水中的活化能更低。估计超临界水中的产率比环境水中高600倍以上。在超临界水中的高收率是由于反应物对超临界水的高溶解度。
A Diels-Alder reaction in supercritical water is studied by means of combined electronic structure and liquid state theories. The target system is the cycloaddition of cyclopentadiene with methyl vinyl ketone. The rate and the yield of the reaction in supercritical water are calculated and compared with those in ambient water. The activation free energies of the two isomers, cis and trans, are compared. The results are in agreement with the experimentally observed increase of the rate and the yield. The solvation effect for the rate constant is decreased in supercritical water, but the rate is increased because of the thermal excitation rather than the solvation effect. The trans-conformer has shown less activation energy in ambient water and supercritical water compared to the cis-conformer. The estimated yield in supercritical water is more than 600 times higher than in ambient water. The high yield in supercritical water is due to the high solubility of the reactants to supercritical water.