Propylene is the second member of the olefin series, with a structural formula of CH2=CHCH3. It is an important organic industrial raw material after ethylene and benzene. It is generally separated from thermal cracking and catalytic cracking gases, and is also a by-product of light oil cracking to produce ethylene. The molecule contains unsaturated carbon-carbon double bonds, which can undergo addition reactions with hydrogen, halogens, hydrogen halides, etc., and can also undergo addition polymerization reactions. It is a raw material for producing synthetic resins, synthetic rubber, synthetic fibers and plastics such as acrylonitrile, polypropylene, ethylene propylene rubber, propylene oxide, and acetone. It has an anesthetic and asphyxiating acute poisoning effect. When mixed with oxygen, it exhibits anesthesia, and when mixed with air, it has a stronger asphyxiating effect than Chemicalbook. At a concentration of 30-40%, consciousness is lost in 20 seconds. Chronic poisoning is still unclear to humans. Mice were exposed 20 times at a concentration of 35% in 58 days, and their livers showed slight fatty infiltration. Air quality standard: The Soviet Union stipulated 1.5ppm (3.0mg/m3, 24-hour average as long-term standard, 30 minutes as short-term standard), the German Democratic Republic 1.0ppm (2.0mg/m3, 24-hour average as long-term standard), 1.5ppm (3.0mg/m3, 30 minutes average as short-term standard). This information is edited by Xiaonan of Chemicalbook.