Title: Propylene Glycol
CAS Registry Number: 57-55-6
CAS Name: 1,2-Propanediol
Synonyms: methyl glycol; 1,2-dihydroxypropane
Molecular Formula: C3H8O2
Molecular Weight: 76.09
Percent Composition: C 47.35%, H 10.60%, O 42.05%
Line Formula: CH3CHOHCH2OH
Literature References: Prepn from glycerol: Raschig, Prahl,
Ber. 61, 185 (1928). Prepn of levorotatory propylene glycol from hydroxyacetone by yeast reduction: Levene, Walti,
Org. Synth. coll. vol. II, 545 (1943). Synthesis of S-(+)-form: C. Melchiorre,
Chem. Ind. (London) 1976, 218. Manuf from propylene oxide by hydration:
Faith, Keyes & Clark's Industrial Chemicals, F. A. Lowenheim, M. K. Moran, Eds. (Wiley-Interscience, New York, 4th ed., 1975) pp 688-691. Toxicity data: W. Bartsch
et al., Arzneim.-Forsch. 26, 1581 (1976). GC/MS determn in plasma: C. Giachetti
et al., Biomed. Environ. Mass Spectrom. 18, 592 (1989). Review of toxicity, metabolism and biochemistry: Ruddick,
Toxicol. Appl. Pharmacol. 21, 102 (1972); of toxicology and human exposure:
Toxicological Profile for Ethylene Glycol and Propylene Glycol (US DHHS, PB98-101109, 1997) 250 pp.
Derivative Type: dl-Form
Properties: Hygroscopic, viscous liquid. Slightly acrid taste. d425 1.036. mp -59°. bp760 188.2°; bp400 168.1°; bp200 149.7°; bp100 132.0°; bp60 119.9°; bp40 111.2°; bp20 96.4°; bp10 83.2°; bp5 70.8°; bp1.0 45.5°. Flash pt, open cup: 210°F (99°C). Miscible with water, acetone, chloroform. Sol in ether. Will dissolve many essential oils, but is immiscible with fixed oils. It is a good solvent for rosin. Under ordinary conditions propylene glycol is stable, but at high temps it tends to oxidize giving rise to products such as propionaldehyde, lactic acid, pyruvic acid and acetic acid. LD50 orally in rats: 25 ml/kg (Bartsch).
Melting point: mp -59°
Boiling point: bp760 188.2°; bp400 168.1°; bp200 149.7°; bp100 132.0°; bp60 119.9°; bp40 111.2°; bp20 96.4°; bp10 83.2°; bp5 70.8°; bp1.0 45.5°
Flash point: Flash pt, open cup: 210°F (99°C)
Density: d425 1.036
Toxicity data: LD50 orally in rats: 25 ml/kg (Bartsch)
Derivative Type: l-Form
Properties: bp12 88-90°, bp760 187-189°. [a]D20 -15.0°.
Boiling point: bp12 88-90°; bp760 187-189°
Optical Rotation: [a]D20 -15.0°
Derivative Type: d-Form
Properties: bp14 94-96°. [a]D20 +15.84° (neat). d25 1.04.
Boiling point: bp14 94-96°
Optical Rotation: [a]D20 +15.84° (neat)
Density: d25 1.04
Use: Nontoxic antifreeze in breweries and dairy establishments. Substitute for ethylene glycol and glycerol. In the manuf of synthetic resins and de-icing solutions. Emulsifier in foods; solvent for food colors and flavors. Pharmaceutic aid (humectant, solvent). As mist to disinfect air; to create artificial smoke and mist for theatrical use.
Therap-Cat-Vet: Glucogenic (orally) in ruminants.
