CHEMICAL AND PHYSICAL PROPERTIES
| Physical Description | Thick odorless colorless liquid. Mixes with water. (USCG, 1999) |
|---|---|
| Color/Form | Colorless viscous liquid |
| Odor | Practically odorless |
| Taste | Practically tasteless |
| Boiling Point | 370.8 °F at 760 mmHg (NTP, 1992) |
| Melting Point | -76 °F (NTP, 1992) |
| Flash Point | 210 °F (NTP, 1992) |
| Solubility | greater than or equal to 100 mg/mL at 70 °F (NTP, 1992) |
| Density | 1.04 at 68 °F (USCG, 1999) - Denser than water; will sink |
| Vapor Density | 2.62 (NTP, 1992) - Heavier than air; will sink (Relative to Air) |
| Vapor Pressure | 0.08 mmHg at 68 °F ; 0.13 mmHg at 77 °F (NTP, 1992) |
| LogP | -0.92 |
| Stability/Shelf Life | At cool temperatures, propylene glycol is stable in a well-closed container, but at high temperatures, in the open, it tends to oxidize, giving rise to products such as propionaldehyde, lactic acid, pyruvic acid, and acetic acid. Propylene glycol is chemically stable when mixed with ethanol (95%), glycerin, or water; aqueous solutions may be sterilized by autoclaving. |
| Autoignition Temperature | 700 °F (USCG, 1999) |
| Decomposition | When heated to decomposition it emits acrid smoke and irritating fumes. |
| Viscosity | 0.581 cP at 20 °C |
| Heat of Combustion | 431.0 kg cal/mole |
| Heat of Vaporization | 168.6 cal/g at BP |
| Surface Tension | 40.1 dynes/cm at 25 °C |
| Refractive Index | [n]D/20: 1,431-1,433 |
| Dissociation Constants | 14.9 |
| Relative Evaporation Rate | 0.01, relative to butyl acetate |
| Kovats Retention Index | 722 719 753 745 710 716 711 710 710 745 |
| Other Experimental Properties | Specific heat: 0.590 cal/g at 20 °C; hygroscopic |
| Chemical Classes | Other Classes -> Alcohols and Polyols, Other |
COMPUTED DESCRIPTORS
| Molecular Weight | 76.09 g/mol |
|---|---|
| XLogP3 | -0.9 |
| Hydrogen Bond Donor Count | 2 |
| Hydrogen Bond Acceptor Count | 2 |
| Rotatable Bond Count | 1 |
| Exact Mass | 76.052429494 g/mol |
| Monoisotopic Mass | 76.052429494 g/mol |
| Topological Polar Surface Area | 40.5 Ų |
| Heavy Atom Count | 5 |
| Formal Charge | 0 |
| Complexity | 20.9 |
| Isotope Atom Count | 0 |
| Defined Atom Stereocenter Count | 0 |
| Undefined Atom Stereocenter Count | 1 |
| Defined Bond Stereocenter Count | 0 |
| Undefined Bond Stereocenter Count | 0 |
| Covalently-Bonded Unit Count | 1 |
| Compound Is Canonicalized | Yes |
PRODUCT INTRODUCTION
description
Propylene glycol is a synthetic liquid substance that absorbs water. Propylene glycol is also used to make polyester compounds, and as a base for deicing solutions. Propylene glycol is used by the chemical, food, and pharmaceutical industries as an antifreeze when leakage might lead to contact with food. The Food and Drug Administration (FDA) has classified propylene glycol as an additive that is “generally recognized as safe” for use in food. It is used to absorb extra water and maintain moisture in certain medicines, cosmetics, or food products. It is a solvent for food colors and flavors, and in the paint and plastics industries. Propylene glycol is also used to create artificial smoke or fog used in fire-fighting training and in theatrical productions. Other names for propylene glycol are 1,2-dihydroxypropane, 1,2-propanediol, methyl glycol, and trimethyl glycol. Propylene glycol is clear, colorless, slightly syrupy liquid at room temperature. It may exist in air in the vapor form, although propylene glycol must be heated or briskly shaken to produce a vapor. Propylene glycol is practically odorless and tasteless.