Block polycondensation of monochloroacetic acid sodium salt

Block polycondensation of a monochloroacetic acid sodium salt in the free-poured state proceeds with a high temperature gradient between the center of reaction vessel and thermostat. A method for controlling the process kinetics is proposed for the conditions when this gradient does not exceed 5-10°C. It was found that the reaction is characterized by a high value of the apparent activation energy, reaching 150 kJ/mol at 135-145°C and increasing to 175 kJ/mol at 145-155°C, DSC data showed that the main exothermal effect may be accompanied by two endothermal peaks, the post-polycondensation process being probably related to the partial melting of the salt. The true thermal effect of the reaction, not complicated by side phase transitions, is estimated at 150 kJ/g.