Air Products and Chemicals, Inc.

Stephen Charles Webb

Francis Joseph Waller

James F Nangeroni

John B Appleby

Brian Thomas Carvill

Beth Ann Frey

An improved process for the continuous production of poly(vinyl alcohol) which involves purifying poly(vinyl acetate) paste exiting from a polymerization reactor and dissolving the substantially pure poly(vinyl acetate) in a hydrolytic alcohol-containing solvent for subsequent saponification to produce poly(vinyl alcohol). Poly(vinyl acetate) paste, containing poly(vinyl acetate), vinyl acetate, and solvent, is heated to a temperature above the glass transition temperature but below a temperature which will degrade the poly(vinyl acetate) and is fed into a flashing area of an extruding devolatilization device. Vinyl acetate and solvent are flashed through vent ports in the flashing area of the devolatilization device and can then be recycled to a polymerization reactor, if desired. A substantially pure poly(vinyl acetate) melt, exiting the flashing area, is conveyed to a mixing area of the devolatilization device where it is mixed with a hydrolytic alcohol-containing solvent to form a solution for subsequent processing in a saponification unit.

Continuous process for the preparation of poly(vinyl acetate) for

A liquid-phase process for hydrolyzing a carboxylic acid alkyl ester having 2 to 18 carbon atoms to provide a product mixture comprising a carboxylic acid and an alcohol comprising contacting a feedstock comprising the carboxylic acid alkyl ester and water with an acidic carbon catalyst under reaction conditions sufficient to form the product mixture comprising the carboxylic acid and the alcohol. Suitable acidic carbon catalysts include charcoal and carbons produced from a variety of sources including coconut shells, coal, wood and peat. Carbon catalysts may be rendered acidic by treatment with nitric acid.

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Emmaus, PA, United States of America

Stephen Charles Webb