Production method for high-purity hydrogen chloride gas

A method for producing a high-purity hydrogen chloride gas, comprising performing a purification process that includes the following 1) to 3) by using, as a raw material, a byproduct hydrogen chloride gas generated when producing vinyl chloride by thermally decomposing 1,2-dichloroethane:

• 1) generating a crude hydrochloric acid by allowing water to absorb the byproduct hydrogen chloride gas;
• 2) generating a volatile organic impurity-removed hydrochloric acid by bringing the crude hydrochloric acid obtained in 1) into contact with an inert gas supplied from a supply pipe, at a liquid temperature of 20 to 45° C. to dissipate volatile organic impurities;
• and
• 3) generating a high-purity hydrogen chloride gas by supplying the volatile organic impurity-removed hydrochloric acid obtained in 2) to a distillation column and performing distillation under conditions of a column bottom temperature of higher than 60° C. and 108° C. or lower and a column top temperature of 60° C. or lower to distill out a high-purity hydrogen chloride gas.