This article explores hydrolysis reaction mechanism and optimal process conditions of the poly ( 6- hydroxycaproic acid) under alkalinity conditions. The results show that the greater the alkalinity

the greater the concentration of OH

-

and affinity groups [OH

-

] direct attack on poly(6-hydroxy acid) ester group structure

make the ester bond cleavage reaction occurs

generating small molecule 6-hydroxy acid. Reaction process conditions are relatively mild. In the collector constant heating magnetic stirrer can complete depolymerization with the temperature of 100℃. Under the conditions that sodium hydroxide/poly (6-hydroxy acid) molar ratio of 4. 4

glycol/poly (6-hydroxy acid) molar ratio of 6. 5

water consumption of 100g

catalyst of 0. 1g

reaction time of 2h

the reaction temperature of 100℃

6- hydroxycaproic acid yield up to 84. 07%.The smaller the alkalinity

the smaller the concentration of OH

-

and in the early stage of the reaction

the affinity group [-OCH

2

CH

2

OH] was dominant

and the probability of occurrence of alcoholysis reaction is great

and alcoholysis reaction and alkaline reaction are mutually promoting in the entire reaction system. Reaction process conditions are relatively harsh

must be fully depolymerization at 180℃ sealed autoclave. Under the conditions that sodium bicarbonate/ poly(6-hydroxy acid) molar ratio of 1. 1

glycol/poly( 6-hydroxy acid) molar ratio of 3

water consumption of 100g

catalyst of 0.1g

reaction time of 1h

the reaction temperature of 180℃~190℃

6- hydroxycaproic acid yield up to 90.38%. In the whole reaction system

ethylene glycol is used as a solvent.