气相中HRnCCH和X(X=H_2O,NH_3)反应机理的理论研究

Theoretical Investigation on the Reaction Between HRnCCH and X(X= H_2O,NH_3) in Gas Phase

在CCSD(T)//MP2/aug-cc-pVTZ-pp理论水平上,研究了HRnCCH与大气中H2O及NH3分子反应的机理,反应主要包括HRnCCH与HRnOH及HRnNH2之间的转化、H2O和NH3在HRnCCH中的碳碳三键上的加成反应以及HRnCCH与双分子水反应等.结果表明,HRnCCH与H2O反应生成HCCH和HRnOH及HRnCCH与NH3反应生成HCCH和HRnNH2的能垒分别为54.1和75.2 kJ/mol,而生成HRnCHC(OH)H,HRnC(OH)CH2,HRnCHC(NH2)H和HRnC(NH2)CH2的活化能分别为219.6,220.5,174.4和182.4kJ/mol,此结果表明HRnCCH反应性较弱且是稳态存在的.此外,在HRnCCH与H2O反应中加入单个水分子,仍然生成HRnCHC(OH)H,但反应活化能却降低了96.4 kJ/mol,说明水分子对该反应有明显的催化作用.

The reaction mechanisms of HRnCCH with H2 O, NH3 were explored at the CCSD（ T）//MP2/aug-cc-pVTZ-pp level of theory. This investigation involved the conversion between HRnCCH and HRnOH, HRnCCH and HRnNH2 , and the water, water dimer, and ammonia gas molecule addition to the C≡C bond in the HRnCCH, respectively. The calculated results show that the HCCH＋HRnOH is produced by the reaction of HRnCCH＋H2 O with an activated barrier of 54.1 kJ/mol and HCCH＋HRnNH2 is yielded via the reaction of HRnCCH＋NH3 with a estimated barrier of 75.2 kJ/mol. However, the formations of HRnCHC （ OH ） H, HRnC（OH）CH2, HRnCHC（NH2）H and HRnC（NH2）CH2 have the respective barrier of 219.6, 220.5, 174.4 and 182.4 kJ/mol. Therefore, the reactivity of HRnCCH is of quite weakness at the environments in-vestigated herein, which indicates that HRnCCH could be existed under these conditions. In addition, the second water molecule introduced into the HRnCCH＋H2 O reaction leads to the remarkable reduction for the barrier of the formation of HRnCHC（OH）H to 123.2 kJ/mol, in which the second water molecule plays a strong catalytic role in the reaction of HRnCCH with water.