The inhibiting effect of lead tetraethyl I. The effect of lead compounds on the vapour phase slow oxidation of di is opropyl ether and on the ignition of diethyl ether

Abstract

The effect of lead tetraethyl on various pressure-temperature regions of ether combustion is described. The inhibiting effect was found to persist after prolonged evacuation of the apparatus. Various experiments suggested that this was due to the deposition of lead oxide. Work has therefore been carried out to determine the effects of the oxides of lead on the slow oxidation and on the ignition of ethers. It is found that lead monoxide gives an inhibiting effect profound, persistent and in every way similar to that of lead tetraethyl. Experiments show that it does this by a surface destruction of chain centres. It is further shown that, on oxidation, lead tetraethyl gives rise to a fog of (probably lead monoxide) particles. Its inhibiting effect is then exerted either by these colloidal particles or by the film of lead monoxide to which they give rise on the walls of the vessel. Lead tetraethyl and lead monoxide inhibit, at both 'low' and 'high' temperatures, both the slow oxidation of diisopropyl ether and the process leading to hot flames of diethyl ether. They have no effect on the induction period preceding a cool flame in diethyl ether and only a slight effect on the cool-flame ignition limit. They both reduce the pressure kick due to a cool flame. These results are briefly discussed and are related to other published work.