Vinyl acetate

Vinyl acetate is a small molecule: a vinyl group (two carbons joined by a double bond) attached to an acetate group from acetic acid. It's a colorless, flammable liquid with a sweet, fruity smell, and one of the most important building blocks for glues, paints and coatings.

It's made in one step from three inputs. Ethylene gas, acetic acid vapor and oxygen pass together over a palladium catalyst at about 150 to 200 °C. The oxygen takes a hydrogen from the ethylene and another from the acetic acid, forming water, and the two leftover pieces join into vinyl acetate. Only part of the feed reacts on each pass, so the product is separated by distillation and the unused gases go round again.

The double bond is what makes vinyl acetate useful: it can open and link with others into long chains. Polymerized, it gives polyvinyl acetate, the white wood glue and a common paint binder. Treated further, that polymer becomes polyvinyl alcohol, the film inside an LCD polarizer.