Formation of HCNO and HCN in the 193 nm photolysis of H2CCO in the presence of NO

The products obtained from the ArF laser photolysis of H2CCO in the presence of a large excess of NO at T=298 K and p=3.5 mbar in He bath gas were investigated in a tubular flow reactor by time-resolved mass spectrometry. The main reaction products observed in the presence of NO were HCNO and HCN. The measured yields, ΓHCNO=0.78±0.18 and ΓHCN=0.19±0.04, respectively, were attributed to the contributions of the reactions(1a)CH2+NO→HCNO+H(1b)CH2+NO→HCN+OHand(2a)HCCO+NO→HCNO+CO(2b)(HCCO+NO→HCN+CO2The time-resolved measurements are compared to results of preceding end product analyses by Fourier transform IR spectroscopy.