Recovery of purified vinyl acetate monomer, of sufficient quality to be immediately reused

摘要

Steam is introduced into the aq. phase, which contains vinyl acetate homopolymer or vinyl acetate copolymer; together with vinyl acetate monomer. The vapour phase released by the steam, is withdrawn by means of a water ring pump (2), for which the working fluid, water, is recirculated around the loop at a temp. of 5-30 deg C. From this recirculation loop, water enriched with vinyl acetate is continuously abstracted. The vinyl acetate then separates from the water phase. The vinyl acetate is then extracted using water, thereby reducing the acetaldehyde content, to isolate the purified product. Also claimed is a suitable plant for the execution of the above process. Pref. the water ring pump (2) circuit (6) is in series with the pump reservoir (3), recirculation pump (4) and heat exchanger (5). The overflow from the reservoir (3) is sent (8) to the separator (9). Raw vinyl chloride separated out and is transferred to the raw vinyl chloride tank (12), which in turn feeds the column (16). This has a water supply (17), and a purified vinyl acetate offtake line (18).