甲醛与甲酸相互作用的理论研究

Theoretical studies on the interaction between formaldehyde and formic acid

在MP2/6-31G(d,p)水平上,对H2CO和HCOOH进行优化设计,得到4种稳定H2CO…HCOOH复合物。并且寻找了部分构型转化反应的过渡态,同时计算了转化反应的速率常数。在MP2/6-31G(d,p)水平上进行基组重叠误差(BSSE)校正。最终获得相互作用能,并利用自然键轨道分析揭示了H2CO和HCOOH相互作用的本质。计算结果表明,4种复合物的相对稳定性为:M3>M1>M4>M2。在形成复合物时发生了电荷转移,在M1、M2、M3中方向从甲醛向甲酸转移电荷依次为3.0 me、8.9 me、24.2 me,而在M4中方向从甲酸向甲醛转移电荷为1.6 me。同时发现M4极不稳定,仅需2.14 kJ/mol能垒就可转化为M3,反应速率常数为2.61×1012/s。

The reaction for formaldehyde and formic acid was studied by the MI2 methoa, lne geome- tries of the complexes and transition state were optimized at MP2/6-31 G（d,p） level. By means of the conventional transition state theory, the rate constant was calculated. The interaction energies of complexes have been corrected by the basis set superposition error （BSSE） energies. The result of the theoretical study indicated that the thermodynamic stability of complexes is M3 〉 M1 〉 M4 〉 M2. The reaction pathway from M3 to M4 through bond rotation was found. The activation energy via M4--＋TSM4/M3---rM3 is 2.14 kJ/mol and the rate constant is 2.61 x 10^2/s.