氢甲酰化反应溶剂效应的量子化学研究

在B3LYP/6-31G(d, p)(Rh和P采用LANL2DZ + Polar)水平下,利用自洽反应场（SCRF）的Onsager模型,系统研究了C6H12、C6H6、THF、CH2Cl2、CH3OH和H2O（相对介电常数ε分别为2.02、2.25、7.58、8.93、32.63和78.39）六种溶剂对乙烯氢甲酰化反应中各驻点的结构和反应机理的影响.分别在上述溶剂中优化了反应物、产物、中间体和过渡态的结构,并计算了自由能和活化自由能.计算结果表明,不同溶剂对反应势能面上各驻点的结构和能量均有一定的影响,而且随着相对介电常数ε的增加,反应的活化自由能下降.水是以上六种溶剂中最佳的溶剂,这与大量的实验研究结果一致.

Quantum Chemical Investigation of Solvent Effects on Hydroformylation Reaction

A theoretical investigation of solvent effects on hydroformylation has been carried out at the B3LYP/6-31G (d, p) level (LANL2DZ + Polar for Rh, P) via Onsager model. All stagnation points in the reaction potential profile are optimized completely under condition of cyclohexane (C6H12, ε=2.02), benzene (C6H6, ε=2.25), tetrahydrofuran (THF, ε=7.58), dichloromethane (CH2Cl2, ε=8.93), methanol (CH3OH, ε=32.63) and water (H2O, ε=78.39) as solvent respectively. The free energies and activating free energies are also calculated at the same level and comparison of the data in different solvents are made at all points. These results demonstrate that the activating free energies fall down with increasing of ε value of solvent. Therefore, water with ε=78.39 as solvent for hydroformylation of olefin is considered to be better than the others. The conclusion is consistent with a body of experimental studies.