Explosion of acetylene–chlorine mixture at room temperatures initiated by small additions of oxygen: Kinetic study and mechanism

Oxygen added in amounts of 0.01-0.1% was found to cause the explosion of an acetylene–chlorine mixture at temperatures as low as ?78°C. Explosion occurrence and nature depend on the mode of mixing the reactants, the effect of oxygen being associated with concentration limits. The dependence of explosion-inducing oxygen amounts on temperature, pressure, concentrations of reactants, reactor surface type and area, additions of inert gases, and reaction products were investigated. The effect of light on the C₂H₂ + Cl₂ + O₂ was studied. The composition of gaseous products resulting from acetylene–chlorine mixture explosion in the presence of minute amounts of oxygen, from a slow reaction inhibited and noninhibited by oxygen, and also from explosion at 400°C in the absence of oxygen, was determined. The results obtained point to the fact that any acetylene–chlorine mixture flash caused by small amounts of oxygen is a branched chain reaction involving activated particles, chain branching presumably being associated with the decomposition of radical CHCl=CHOO* → CH + HCl + CO₂.