Abstract: Disclosed is a method of thermally stabilizing an effluent stream from an industrial process, such as a photolithographic process, to allow thermally manageable recovery of the solvent. In the separation and recovery process the solvent is exposed to temperatures that can cause polymerization of the relatively small amounts of monomer still contained therein. This polymerization is an exothermic polymerization, which can accelerate the polymerization of the remaining monomer, potentially causing a thermally initiated, exothermic, run away polymerization. Run away, thermally initiated, exothermic polymerization can materially degrade the solvent. The thermally initiated, run away exothermic reaction is inhibited by the inclusion of a thermal stabilizer or polymerization inhibitor.

Abstract: Disclosed is a method of recovering a cyclic alkylene carbonate, such as propylene carbonate, from an effluent stream of a process in which the cyclic alkylene carbonate removes an organic photoresist material from a substrate. The effluent is a cyclic alkylene carbonate effluent, e.g., a propylene carbonate effluent, of the carbonate, water, and polymeric solids. In the recovery process the cyclic alkylene carbonate effluent is fed to a heat exchanger, and separated into (i) water and volatiles, and (ii) cyclic carbonate. This lowers the concentration of water in the cyclic alkylene carbonate to a level that is low enough to substantially avoid hydrolysis of cyclic alkylene carbonate to the corresponding glycol. The dewatered cyclic alkylene carbonate is evaporated to separate the cyclic alkylene carbonate from high boiling materials and polymeric solids. The dewatered cyclic alkylene carbonate is separated into (i) a cyclic alkylene carbonate fraction, and (ii) a photoresist solids fraction.