colorless volatile transparent liquid, sweet, slightly odorous. Soluble in acetone, benzene, carbon tetrachloride, ethyl ether, ethanol and other organic solvents. Slightly soluble in water, and water to form an azeotropic mixture. Relative density 0.8060. Freezing point -83 ~- 84 ºC. Boiling point 77.3 °c. Flash point -5 °c. Refractive index 3888. Viscosity (25 deg C) 0.34mPa.s. Vapor pressure (20 degrees C) 11, 07kPa. The vapor of this product can form explosive mixture with air, and the explosion limit (25 ºC) is 3.05% ~(17.0±0.5)%(volume). Pure products are easy to self-polymerize, especially in the absence of oxygen or exposure to visible light, more easily polymerized, in the presence of concentrated alkali can be strongly polymerized.