| 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. The photoresist materials fractions contains photoresist material in the alkylene carbonate. The cyclic alkylene carbonate fraction is further separated in a fractionation means into a higher vapor pressure alkylene glycol fraction, and a lower vapor pressure alkylene carbonate fraction. |