Theoretical Study on the Reaction Mechanism of Ketene CH2CO with Isocyanate NCO Radical

• 来源期刊: 中国化学（英文版）
• 年，卷（期）: 2007,（8）
• 页码范围: 1105-1111
• 页数: 7页
• 语种: 英文

摘要

The bimolecular single collision reaction potential energy surface of an isocyanate NCO radical with a ketene CH2CO molecule was investigated by means of B3LYP and QCISD(T) methods. The computed results indicate that two possible reaction channels exist on the surface. One is an addition-elimination reaction process, in which the CH2CO molecule is attacked by the nitrogen atom at its methylene carbon atom to lead to the formation of the intermediate OCNCH2CO followed by a C-C rupture channel to the products CH2NCO+CO. The other is a direct hydrogen abstraction channel from CH2CO by the NCO radical to afford the products HCCO+HNCO. Because of a higher barrier in the hydrogen abstraction reaction than in the addition-elimination reaction, the direct hydrogen abstraction pathway can only be considered as a secondary reaction channel in the reaction kinetics of NCO+CH2CO. The predicted results are in good agreement with previous experimental and theoretical investigations.