Decomposition of Methyl Acetylene

Abstract

METHYL ACETYLENE (propyne) is akin to acetylene in being an endothermic compound the induced decomposition of which will support a flame in the absence of air. The work now reported and a parallel investigation¹ have shown that as in the case of acetylene there is a critical pressure below which a flame is not propagated in pure propyne vapour. This low-pressure limit of propagation has been determined in a cylindrical vessel of internal dimensions 2 in. diameter by 7 in. long mounted vertically; the pressure of the vapour in the vessel was measured by means of a Bourdon gauge with a steel tube. A fuse-wire igniter supported on the vertical axis near the bottom of the chamber was used to ignite the vapour ; the wire, a 1-in. length of 0.0135 in. diameter tinned copper, was energized by a 12 volt a.c. supply. Determinations were made at approximately 20° C. and at 120° C. by increasing the pressure of propyne vapour in the vessel until propagation occurred (indicated by a pressure rise) when the igniter was fired.