Mechanism for the gas-phase reaction between NO3 and furan: A theoretical study

The reaction mechanism of NO3 + furan on the doublet potential energy surface has been studied at the CCSD(T)/6-311++G(d,p) level based on the geometric parameters optimized at the B3LYP/6-311++G(d, p) level of theory. The calculations reveal that the addition-elimination mechanism dominates the NO3 + furan reaction and the direct hydrogen abstraction pathways are negligible. The addition–elimination mechanism involves initial addition of NO3 to the furan ring to give furan–ONO2 intermediate (IN1). Initially formed intermediate IN1 has enough energy to undergo unimolecular rearrangement. The most energetically favorable channel is found to be the formation of 3H-furan-2-one via a simultaneous 1,2-H migration and the loss of NO2.