Propylene Oxide

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Alias: 1,2-epoxypropane, propylene oxide.

Abbreviation: PO.

Molecular formula: C₃H₆O, molecular weight: 58.08. CAS number: 75-56-9, EINECS number: 200-879-2.

Structural formula:

Physical and Chemical Properties

Propylene oxide is a colorless, transparent liquid with an odor similar to diethyl ether. Boiling point: 34.2℃, distillation range: 33–37℃. Freezing point/melting point: approximately -104℃, viscosity (20℃): 0.3 mm²/s, relative density (20℃): 0.830 (0.829–0.831), vapor pressure (20℃): 59 kPa. Flash point (PMCC): -37℃, ignition point: 465℃. Explosive limits in air (volume fraction): 1.8%–36%. Vapor density is twice that of air. Soluble in water, solubility (20℃): 41 g/100 mL.

Characteristics and Uses

Propylene oxide undergoes ring-opening polymerization in the presence of alkaline catalysts or special catalysts, and is mainly used in the production of polyether polyols. Polyether polyols are the main raw materials for polyurethane materials, especially polyurethane foam plastics, and approximately two-thirds of the world’s PO is used to produce polyether polyols. Propylene oxide is also used in the production of propylene glycol, non-ionic surfactants (including foam stabilizers for polyurethane foam plastics), flame-retardant polyols, etc.