The slow combustion of methyl alcohol. A general investigation

Abstract
The slow combustion of methyl alcohol in an uncoated Pyrex vessel has been investigated at temperatures between 430 and 470°C, and at pressures below atmospheric. The kinetics of the reaction were studied by means of pressure-time curves. There was no period of negligible pressure change, the reaction accelerating from a small to the maximum rate. Both the initial and the maximum rate were sensitive to surface conditions. The maximum rate was increased by the addition of ‘inert’ gas, and varied approximately as the square of the alcohol pressure and was independent of the pressure of oxygen. The overall activation energy was 53 and 61 kcal in an old and a new vessel respectively. The products of the reaction were carbon monoxide and water with small amounts of formaldehyde, hydrogen peroxide, carbon dioxide and hydrogen. The pressure change was found to be a true measure of the extent of reaction. The pressure of formaldehyde rose to a maximum at the time of the maximum rate, and this maximum pressure was independent of oxygen pressure and proportional to the pressure of alcohol. The effect of water, carbon monoxide, formaldehyde, and aniline and o-toluidine, added initially, was investigated. It is suggested that the oxidation involves a chain mechanism with delayed branching, the primary initiation reaction being rapid compared to those in the slow combustions of many other fuels. A reaction scheme, which explains the kinetic and analytical results, is proposed, HO2 radicals propagating the chains and terminating them by reaction on the walls.