Propylene glycol is a chemical reagent that is miscible with water, ethanol and a variety of organic solvents, and its chemical formula is C3H8O2. Under normal conditions, it is a colorless viscous liquid, almost tasteless, and slightly sweet. Propylene glycol can be used as a raw material for unsaturated polyester resin. In cosmetics, toothpaste and soap, it can be used as a wetting agent in combination with glycerin or sorbitol. In hair dyes, it is used as a moisture-conditioning and hair-leveling agent, also as an antifreeze agent, and also used in cellophane, plasticizer and pharmaceutical industries.
English chemical name: 1,2-propanediol
Alias: propylene glycol, 1,2 propylene glycol.
Molecular formula: C3H8O2
Relative molecular weight: 76.09
Relative density: (20/20℃)1.0381
Structural formula: CH3—CHOH—CH2OH (1,2-propanediol) or CH2OH—CH2—CH2OH (1,3-propanediol)
Appearance: Colorless, hygroscopic, viscous liquid, almost tasteless and odorless.
Boiling point: 188.2
Melting point: -59°C
Ignition point: 421.1℃
Viscosity (20 ℃) 56.0mpa.s,
Surface tension: 72.0 (25℃)
Specific heat capacity (20 ℃) 2.49kJ/(kg.℃),
Heat of vaporization (101.3kpa) 711kJ/kg.
Propylene glycol is an important raw material for unsaturated polyesters, epoxy resins, polyurethane resins, plasticizers, and surfactants. The amount in this area accounts for about 45% of the total consumption of propylene glycol. This unsaturated polyester is used in large quantities on the surface. Coatings and reinforced plastics. Propylene glycol has good viscosity and hygroscopicity, and is widely used as a moisture absorbent, antifreeze, lubricant and solvent in the food, medicine and cosmetic industries. In the food industry, propylene glycol and fatty acids react to produce propylene glycol fatty acid esters, which are mainly used as food emulsifiers; propylene glycol is an excellent solvent for seasonings and pigments. Because of its low toxicity, it is used as a solvent for spices and food coloring in the food industry. Propylene glycol is commonly used in the pharmaceutical industry as a solvent, softener and excipient for the manufacture of various ointments and ointments, and as a solvent for blending agents, preservatives, ointments, vitamins, penicillins, etc. in the pharmaceutical industry. Because propylene glycol has good miscibility with various fragrances, it is also used as a solvent and softener for cosmetics. Propylene glycol is also used as a tobacco moisturizer, antifungal agent, food processing equipment lubricating oil and food marking ink solvent. An aqueous solution of propylene glycol is an effective antifreeze. It is also used as a tobacco wetting agent, antifungal agent, fruit ripening preservative, antifreeze and heat carrier.