Abstract: The necessity of opening a large polymerization reactor, in order to introduce a polymerization catalyst between charges in the batch suspension of polymerization of vinyl chloride on a commercial scale, is eliminated, thereby avoiding vinyl chloride emissions into the atmosphere, by isolating a segment of a charging conduit for a polymerization reactor containing vinyl chloride under pressure proximate the reactor; partially filling the isolated segment with water; charging the isolated segment above the water therein with a water-insoluble polymerization catalyst; and displacing into the reactor from the catalyst-charged segment first the water therein and then the catalyst therein with vinyl chloride under pressure.

Abstract: Vinyl chloride emissions from the gaseous phase of large scale vinyl chloride batch emulsion polymerizations are reduced by discharging the liquid phase only of the polymerizate to a discharge zone at a pressure differential of 0.1-2.5 atmospheres lower than the reactor provided by residual vinyl chloride in the reactor, maintaining the reactor unopened; and then conducting another vinyl chloride polymerization in the reactor in the presence of the residual vinyl chloride from the prior polymerization.