Wikipedia
β-Propiolactone is an organic compound of the lactone family, with a four-membered ring. It is a clear, colorless liquid with a slightly sweet odor, highly soluble in water and miscible with ethanol, acetone, diethyl ether and chloroform. The word propiolactone usually refers to this compound, although it may also refer to α-propiolactone.
β-Propiolactone is "reasonably anticipated to be a human carcinogen" ( IARC, 1999). It is one of 13 "OSHA-regulated carcinogens," chemicals regarded occupational carcinogens by the Occupational Safety and Health Administration, despite not having an established permissible exposure limit. It was once widely used in the manufacture of acrylic acid and its esters, but its use has been mostly phased out in favor of safer and less expensive alternatives. β-Propiolactone is a sterilizing and sporicidal agent, and has been used to sterilize blood plasma, vaccines, tissue grafts, surgical instruments, and enzymes. The principal current use of propiolactone is an intermediate in the synthesis of other chemical compounds.
β-Propiolactone will slowly react with water and hydrolyze to produce 3-hydroxypropionic acid (hydracryclic acid).