The present invention is directed to reactor systems and processes for producing acrylonitrile and acrylonitrile derivatives. In preferred embodiments of the present invention, the processes comprise the following steps: introducing an epoxide reagent and carbon monoxide reagent to at least one reaction vessel through at least one feed stream inlet; contacting the epoxide reagent and carbon monoxide reagent with a carbonylation catalyst to produce a beta-lactone intermediate; polymerizing the beta-lactone intermediate with an initiator in the presence of a metal cation to produce a polylactone product; heating the polylactone product under thermolysis conditions to produce an organic acid product; optionally esterifying the organic acid product to produce one or more ester products; and reacting the organic acid product and/or ester product with an ammonia reagent under ammoxidation conditions to produce an acrylonitrile product.