A theoretical study of β-hydroxybutenyl with O2 on the HOC4H6OO· potential energy surface

The reaction of β-hydroxybutenyl radicals with O 2 and subsequent reactions are regarded as crucial steps in the low-temperature oxidation of 1,3-butadiene. However, the reaction network is not complete and previous studies failed to include accurate rate constants. In this study, the reaction network of β-hydroxybutenyl radicals with O 2 is supplemented, as well as the temperature- and pressure-dependent rate constants which are investigated by high-level quantum chemical calculation, combining with the transition state theory (TST), the variational transition state theory (VTST) and Rice–Ramsperger–Kassel–Marcus/master equation method (RRKM/ME). The results of quantum chemical calculations indicate that Waddington reaction is the dominant channel, while the intramolecular addition reactions of the radical center atoms to the double bonds are found to be important non-alkyl-analogue reactions. Moreover, some of the reactions are investigated in the present study as well, whose pressure-dependent kinetics have not been reported so far. The calculations indicate that addition reaction of β-hydroxybutenyl with O 2 is pressure independent when the temperature is below 600 K, while above 600 K, the effect of pressure is increasingly significant. Furthermore, the formation of β-hydroxybutenylperoxy is a dominant channel when the pressure is above 1 atm, while below 0.1 atm, other channels begin to take place with the increase in temperature.