Purification of difluoromethane by extractive distillation

A process for separating difluoromethane (HFC-32) from at least one halocarbon of a first mixture comprising difluoromethane (HFC-32) and halocarbon selected from the group consisting of chlorodifluoromethane (CFC-12), 1,1,1-trifluoroethane (HFC-143a), chloropentafluoroethane (CFC-115), and pentafluoroethane (HFC-125), comprising the steps of:

• contacting the first mixture with an extractive agent selected from the group consisting of:
• hydrocarbon extractive agents comprising hydrocarbons having from 5 to 9 carbon atoms and having a normal boiling point greater than about 30° C. and less than about 155° C., oxygen-containing extractive agents comprising alcohols having a normal boiling point greater than about 60° C. and less than about 100° C. and represented by the formula CxH2x+1OH, wherein x is from 1 to 3, and ketones having a normal boiling point greater than about 50° C. and less than about 110° C. and represented by the formula CyH2y+1COCzH2z+1, wherein y and z are 1 or greater and y+z is at most 5, and
• chlorocarbon extractive agents comprising chlorocarbons having a normal boiling point greater than about 39° C. and less than about 150° C. and represented by the formula CsH2s+2-tClt, wherein s is 1 or 2 and t is from 2 to 4 to form a second mixture,
• separating difluoromethane (HFC-32) from at least one halocarbon of the second mixture by extractively distilling the second mixture, and
• recovering difluoromethane (HFC-32) substantially free of at least one halocarbon, with the proviso that when the halocarbon is pentafluoroethane (HFC-125), the chlorocarbon extractive agent may not be methylene chloride.