Theoretical study on the water-catalyzed reaction of glyoxal with OH radical

The quantum chemical calculations are applied to study the reactions of OH with the naked glyoxal and glyoxal with the single water molecule added. The computed results predict that the activated barriers for the H-abstraction of glyoxal by OH are reduced from −0.5 to −2.2 kcal/mol to −3.9 to −7.3 kcal/mol for the cleavage with the H2O molecule involved at the CCSD(T)/6-311++G(2d,2p)//BHandHLYP/6-311++G(d,p) level of theory. In addition, the calculated results show that as for the non-catalyzed process the rate constant is 6.92 × 10−12 cm3 molecule−1 s−1 at the BHandHLYP/6-311++G(d,p) level of theory, which is in agreement with the experimental data, whereas the water-catalyzed the glyoxal with OH radical has a value of 3.62 × 10−9 cm3 molecule−1 s−1 at the CCSD(T)/6-311++G(2d,2p)//BHandHLYP/6-311++G(d,p) level of theory at 298 K. Thus, the calculations show that the single water would enhance the rate constant of the glyoxal with the OH radical.