The CnH free radicals were reported to play an important role in interstellar chemistry. The oxida-tion processes of CnH radicals with n=1—4 had been explored by means of the theoretical and experimental methods. To further understand the reaction properties of the long carbon chain radicals, we report the first theoretical survey of the l-C5H+O2 and l-C6H+O2 reactions at the CCSD(T)/CC-PVTZ+ZPVE//B3LYP/6-311++G( d,p) level. The carbon transfer was found to be the main pathway in the l-C5 H+O2 reaction, giving the main product P2( CO2+C4 H) . Yet, the case is a little different for l-C6 H+O2 . The energy barrier between the C,O-exchange[resulting in P1(CO+HC5O)] and the oxygen transfer[resulting in P3(3O+HC6O)] is only 0. 4 kJ/mol, indicative of their co-predominance. The present results were compared with the shorter l-CnH radicals with O2.%为了探索更长的碳链自由基l-CnH与O2反应的机理,在CCSD(T)/CC-PVTZ+ZPVE//B3LYP/6-311++G(d,p)的计算水平下,讨论了当n=5,6时, l-CnH+O2的各个异构化反应通道。当n=5时,主要反应通道为碳迁移过程,生成主要产物为P2(CO2+C4H)；当n=6时,碳-氧交换[产物为P1(CO+HC5O)]和氧迁移过程[产物为P3(3O+HC6O)]均为主要通道,并具有很高的竞争性。将所得结构与l-CnH(n≤4)+O2的反应机理进行了对比。
展开▼
