采用 CCSD(T)/ cc-pVDZ// B3LYP/6-311++G(d,p)双水平计算方法研究了 CH3 CH2 O+HCHO 反应的微观反应机理.结果表明,标题反应主要存在5个抽氢和3个氢迁移异构化反应通道,其中抽氢通道 R→IMa(CH3 CH2 O…CH2 O)→TS1→ IM1b→P1(CH3 CH2 OH+CHO)为优势通道,其表观活化能为14.65 kJ/ mol.利用变分过渡态理论(CVT)并结合小曲率隧道效应模型计算了主通道 R1在275~1000 K 温度范围内的速率常数 kTST , kCVT 和 kCVT/ SCT ,在此温度区间内表观反应速率常数三参数表达式为 kCVT/ SCT =2.26×10-17 T0.57 exp(-1004/ T),显示具有正温度系数效应.%The mechanism of the reaction between CH3 CH2 O and HCHO was investigated at CCSD(T) cc-pVDZ/ / B3LYP/ 6-311++G( d,p) level. Eight possible reaction channels( five H-abstraction channels and three H-isomerization channels) for the title reaction were identified. The results indicated that channel R→IMa(CH3 CH2 O…CH2 O)→TS1→IM1b→P1(CH3 CH2 OH+CHO) was the most favorable channel with the apparent activation energy of 14. 65 kJ/ mol. The rate constants of the path R1 were evaluated over a tempera-ture range of 275-1000 K via the canonical variational transition state theory(CVT) combined with a small-curvature tunneling correction. The fitted three-parameter expression for the path R1 is kCVT/ SCT = 2. 26×10-17 T0. 57 exp(-1004 / T) and R1 has a positive temperature effect over a temperature range of 275-1000 K.
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