Acrylic acid is the simplest unsaturated carboxylic acid, and its molecular structure is composed of one vinyl group and one carboxyl group. Pure acrylic acid is a colorless clear liquid with characteristic pungent smell, strong acidity and corrosiveness. It is soluble in water, ethanol and ether. It has active chemical properties and is easy to polymerize into transparent white powder. Propionic acid is formed when it is reduced and 2-chloropropionic acid is formed when it is added with hydrochloric acid. Acrylic acid is mainly prepared by homopolymerization or copolymerization. It is used in coatings, adhesives, solid resins, molding compounds and other organic synthesis. Acrylic acid is mainly obtained by oxidation of acrolein or hydrolysis of acrylonitrile. It can also be synthesized by acetylene, carbon monoxide and water, or by pressure oxidation of ethylene and carbon monoxide.