An Experimental Study of 2-Propanol Pyrolysis Chemistry

In the present study, 2-propanol pyrolysis experiments were conducted in a rapid compression facility for a range of temperatures from 965 to 1193 K, pressures from 4.4 to 10.0 atm conditions, and times ranging from 2 to 47 ms after end-of-compression. Mixtures were composed of 2-propanol, nitrogen, and argon with the 2-propanol concentration held constant at 1.5% by mole fraction. The production of seven stable intermediate species (methane, acetylene, ethene, ethane, acetaldehyde, propene, and acetone) were measured using fast-gas sampling and gas chromatography. The high concentrations of propene observed experimentally indicated thermal decomposition of 2-propanol via dehydration was significant at all conditions studied. The observation of the simultaneous presence of methane and acetone indicated H atom abstraction from 2-propanol by H and CH₃ radicals was also significant at all conditions. The relative concentrations of methane and acetone indicated an increase in the 2-propanol + CH₃ channel at higher temperature. The experimental data showed negligible sensitivity to over a factor-of-two increase in pressure, indicating pressure-dependent reactions, like the thermal decomposition of 2-propanol via dehydration, were in the high-pressure limit. The experimental results were compared with model predictions made using a recently developed kinetic mechanism for C3-C4 alcohols, and the results showed generally good agreement. The most significant discrepancies were for 2-propanol consumption at the highest temperature condition (T = 1193 K), where 2-propanol consumption was predicted as much higher by the model (by more than an order of magnitude) compared with the experimental results, and at the lowest temperature (T = 965 K), ethane production was predicted as much lower (by more than an order of magnitude) compared with the experimental results.