Propylene glycol

1,2-Propanediol (CAS NO.57-55-6 ), also known as Propylene glycol, is a colorless, odorless, viscous, highly hygroscopic liquid with a faintly sweet taste. It is miscible with water, ethanol, ether, chloroform, acetone and other organic solvents. The solubility to hydrocarbons and chlorinated hydrocarbons is small, but it is strong than ethylene glycol. Propylene Glycol contains an asymmetrical carbon atom, so it exists in two optically active forms (dextrorotatory and sinistrorotatory isomers). And the commercial Propylene Glycol is a racemic mixture.

Physical properties about Propylene Glycol are: (1)ACD/LogP: -1.341; (2)ACD/LogD (pH 5.5): -1.34; (3)ACD/LogD (pH 7.4): -1.34; (4)ACD/BCF (pH 5.5): 1.00; (5)ACD/BCF (pH 7.4): 1.00; (6)ACD/KOC (pH 5.5): 4.44; (7)ACD/KOC (pH 7.4): 4.44; (8)#H bond acceptors: 2; (9)#H bond donors: 2; (10)#Freely Rotating Bonds: 3; (11)Index of Refraction: 1.43; (12)Molar Refractivity: 18.976 cm³; (13)Molar Volume: 73.444 cm³; (14)Polarizability: 7.523 10-24cm³; (15)Surface Tension: 38.0040016174316 dyne/cm; (16)Density: 1.036 g/cm³; (17)Flash Point: 107.222 °C; (18)Enthalpy of Vaporization: 49.011 kJ/mol; (19)Boiling Point: 184.848 °C at 760 mmHg; (20)Vapour Pressure: 0.203999996185303 mmHg at 25°C

Preparation of Propylene Glycol: Propylene Glycol can be obtaine by epoxypropane. It includes direct hydration and indirect hydration. The direct hydration is the reaction of epoxypropane and water at 150-160 °C and 0.78-0 .98 MPa. After evaporation and distillation, Propylene Glycol is obtained. The indirect hydration is the reaction of epoxypropane and water in the presence of catalyst sulfuric acid. In addition, Propylene Glycol also can be produced by direct catalytic oxidation from propylene. The catalyst is anhydrous tertiary butanol.

Uses of Propylene Glycol: Propylene Glycol is an important raw material in unsaturated polyester, epoxy resins, polyurethane resins, plasticizers and surfactants. The amount occupies about 45% of total consumption. This unsaturated polyester is largely used for surface coatings and reinforced plastics. Because of good viscosity and moisture absorption, and non-toxic, Propylene Glycol is widely used as a hygroscopic agent, antifreeze, lubricants and solvents in the food, pharmaceutical and cosmetics industries. In the food industry, Propylene Glycol and fatty acid reacts to produce propylene glycol ester of fatty acid, which is mainly used as food emulsifier. It is also used as solvent for spices, seasonings and food coloring. What's more, 1,2-propanediol is used as a humidifying agent of tobacco, mildew preventive, fruit ripening preservatives, film-forming coatings additives, antifreeze and heat transfer media, etc. It is often used as a substitute for ethanol and glycerol. In pharmaceutical industry, Propylene Glycol is commonly used as solvent in the manufacture of various types of ointment, softener, excipients, preservatives, vitamins, penicillin, etc. As Propylene Glycol has good solubility with various spices, it is also used as solvent of cosmetic and softeners, etc.

When you are using this chemical, please be cautious about it as the following: The Propylene Glycol is low toxicity. So the acute oral toxicity is very low, and large quantities are required to cause perceptible health damage in humans. In the human body, Propylene Glycol is metabolized into pyruvic acid (a normal part of the glucose-metabolism process, readily converted to energy), lactic acid (a normal acid generally abundant during digestion), acetic acid (handled by ethanol-metabolism), and propionaldehyde. So you should avoid contact with skin and eyes.

You can still convert the following datas into molecular structure:
1. Smiles:C([C@@H](C)O)O;
2. InChI:InChI=1/C3H8O2/c1-3(5)2-4/h3-5H,2H2,1H3;

The toxicity data is as follows: