What Is Vinyl Acetate?
Vinyl acetate, the ester of vinyl alcohol and acetic acid, is a clear, colorless, flammable liquid with a sweet aroma and faint pungent odor. It serves as a raw material for organic synthesis, polyvinyl acetate (PVA), polyvinyl alcohol, and paints.
The production of vinyl acetate initially utilized the acetylene process, discovered in 1912, followed by the ethylene process and the ethylidene diacetate process. Major production bases are located in the United States, China, Japan, and Taiwan.
Uses of Vinyl Acetate
Vinyl acetate is primarily employed in the production of polyvinyl acetate and polyvinyl alcohol, which find applications in various industrial and consumer products.
Polyvinyl acetate is widely used in paints, adhesives, artificial turf, denture stabilizers, gum paste, wire, plastic fuel tanks for automobiles, and food packaging containers.
Polyvinyl alcohol serves as a raw material for polarizers in liquid crystal displays, fiber and paper processing agents, emulsion dispersants, and ceramic binders.
Properties of Vinyl Acetate
Vinyl acetate has a melting point of -100.2°C and a boiling point of 72-73°C. It readily polymerizes under light or heat to form polyvinyl acetate, necessitating the inclusion of polymerization inhibitors like hydroquinone.
Hydrolysis of vinyl acetate with dilute acid or alkali yields acetic acid and acetaldehyde. Under ultraviolet light, vinyl acetate decomposes to produce ketones, aldehydes, and alcohols.
It has a molecular formula of C4H6O2, molecular weight of 86.09, and specific gravity of 0.9312. Vinyl acetate is classified as a suspected human carcinogen by the International Agency for Research on Cancer, although there is no evidence of carcinogenicity in humans.
Other Information on Vinyl Acetate
1. Synthetic Methods of Vinyl Acetate
Vinyl acetate is industrially synthesized via the Wacker oxidation reaction, involving the reaction of ethylene and acetic acid with oxygen in the presence of a palladium catalyst. Alternatively, it can be produced by the addition of acetic acid to acetylene using a metal catalyst, with zinc acetate being the current preferred catalyst.
Another method involves the thermal decomposition of ethylidene diacetate to produce vinyl acetate.
2. Synthesis of Polyvinyl Acetate
Radical polymerization of vinyl acetate yields polyvinyl acetate, a colorless, transparent thermoplastic resin. Ethylene-vinyl acetate copolymer can also be synthesized by copolymerizing ethylene and vinyl acetate monomers.
Hydrolysis of the ester acetate bonds of polyvinyl acetate yields polyvinyl alcohol, a highly hydrophilic synthetic resin, as vinyl alcohol cannot be polymerized directly due to its unstable molecular structure.