Department of Chemistry, Purdue University, West Lafayette, Indiana 47909, USA.
J Phys Chem A. 2010 Mar 4;114(8):2806-20. doi: 10.1021/jp9045116.
An ab initio study of OH radical substitution reactions in halogenated carbonyls is conducted. Hydroxyl radical substitution into oxalyl dichloride [ClC(O)C(O)Cl] and oxalyl dibromide [BrC(O)C(O)Br], resulting in the formation of oxalic acid, is presented. Analogous substitution reactions in formyl chloride [ClCH(O)], acetyl chloride [ClC(O)CH(3)], formyl bromide [BrCH(O)], and acetyl bromide [BrC(O)CH(3)] are considered. Energetics of competing hydrogen abstraction reactions for all applicable species are computed for comparison. Geometry optimizations and frequency computations are performed using the second-order Møller-Plesset perturbation theory (MP2) and the 6-31G(d) basis set for all minimum species and transition states. Single point energy computations are performed using fourth-order Møller-Plesset perturbation theory (MP4) and coupled cluster theory [CCSD(T)]. Potential energy surfaces, including activation energies and enthalpies, are determined from the computations. These potential energy surfaces show that OH substitution into ClC(O)C(O)Cl and BrC(O)C(O)Br, resulting in the formation of oxalic acid and other minor products, is energetically favorable. Energetics of analogous reactions with ClCH(O), BrCH(O), ClC(O)CH(3), and BrC(O)CH(3) are also computed.
进行了卤代羰基中 OH 自由基取代反应的从头算研究。介绍了羟基自由基取代草酰二氯 [ClC(O)C(O)Cl] 和草酰二溴 [BrC(O)C(O)Br]，生成草酸。还考虑了类似的取代反应在一氯甲酰基 [ClCH(O)]、乙酰氯 [ClC(O)CH(3)]、一溴甲酰基 [BrCH(O)] 和乙酰溴 [BrC(O)CH(3)] 中进行。为了比较，计算了所有适用物种的竞争氢提取反应的能量。使用二阶 Møller-Plesset 微扰理论 (MP2) 和 6-31G(d) 基组对所有最小物种和过渡态进行了几何优化和频率计算。使用四阶 Møller-Plesset 微扰理论 (MP4) 和耦合簇理论 [CCSD(T)] 进行单点能计算。从计算中确定了包括活化能和焓在内的势能面。这些势能面表明，OH 取代 ClC(O)C(O)Cl 和 BrC(O)C(O)Br，生成草酸和其他少量产物，是有利的。还计算了与 ClCH(O)、BrCH(O)、ClC(O)CH(3)和 BrC(O)CH(3)的类似反应的能量。
