The present invention is directed to reactor systems and processes for producing organic acids through thermolysis of polylactones. In preferred embodiments, the reactor systems and processes are capable of introducing at least one epoxide reagent and carbon monoxide reagent to at least one reaction vessel through at least one feed stream inlet; contacting the at least one epoxide reagent and carbon monoxide reagent with at least one carbonylation catalyst to produce at least one beta-lactone intermediate; polymerizing the at least one beta-lactone intermediate with at least one initiator in the presence of a metal cation to produce at least one polylactone product; and heating the at least one polylactone product under thermolysis conditions to produce at least one organic acid product. Advantageously, the processes of the present invention may control the presence of contaminates, impurities, catalytic materials, and/or reagents to provide for highly pure organic acid products.