1,2-Propanediol
[CAS# 57-55-6]

Identification

• Classification: Chemical pesticide >> Fungicide >> Azole fungicide
• Name: 1,2-Propanediol
• Synonyms: Propane-1,2-diol; Propylene glycol
• Molecular Formula: C₃H₈O₂
• Molecular Weight: 76.09
• CAS Registry Number: 57-55-6
• EC Number: 200-338-0
• FEMA: 2940
• SMILES: CC(CO)O

Properties

• Density: 1.036
• Melting point: -60 °C
• Boiling point: 187 °C
• Refractive index: 1.431-1.433
• Flash point: 99 °C
• Water solubility: miscible

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P261-P305+P351+P338

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Acute toxicity	Acute Tox.	4	H302
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin sensitization	Skin Sens.	1	H317
Specific target organ toxicity - single exposure	STOT SE	3	H336
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411

Discovery and Applications

1,2-Propanediol, also known as propylene glycol, is a versatile compound with important industrial, pharmaceutical, and consumer applications. 1,2-Propanediol was first synthesized in the mid-20th century by the hydration of propylene oxide, a process that remains the primary production method today. Propylene oxide undergoes catalytic hydrogenation under controlled conditions to produce 1,2-propylene glycol. This simple synthetic route ensures high purity and efficiency, making 1,2-propylene glycol readily available for a wide range of applications.

1,2-Propanediol is a clear, colorless, odorless liquid with a slightly sweet taste. Key properties include: It absorbs and retains water, making it useful in formulations where moisture control is required. It is completely miscible with water, facilitating its use in aqueous solutions. It has a low vapor pressure and does not evaporate readily at ambient temperatures. It is stable under normal conditions and does not undergo significant decomposition.

1,2-Propanediol is used in a wide range of industrial applications: Due to its lower toxicity, it is a safer alternative to ethylene glycol in automotive antifreeze formulations. Because of its ability to dissolve a wide range of substances, it is used as a solvent in paints, coatings, and industrial cleaners. It is a key ingredient in the production of polyesters, polyurethanes, and other polymers, where it acts as a precursor or plasticizer.

It can be used as a humectant and solvent in moisturizers, lotions, and creams, helping to retain moisture and improve product texture. It can be used as a solvent and stabilizer for active pharmaceutical ingredients (APIs) in oral, topical, and injectable formulations.

1,2-Propanediol has been approved by regulatory agencies such as the FDA and EFSA for use as a food additive (E1520): It can be used as a preservative in food and beverage products to extend shelf life by controlling water activity and microbial growth. It is also used to dissolve and deliver flavors and food colorings in processed foods and beverages.

1,2-Propanediol is considered environmentally friendly due to its biodegradability and low toxicity compared to other glycols. It is widely used in environmentally friendly formulations and products designed to minimize environmental impact. Ongoing research focuses on expanding the use of 1,2-Propanediol in sustainable technologies, such as renewable energy storage systems and biodegradable polymers. Advances in synthetic methods aim to improve efficiency and reduce production costs, further promoting its application in various industries.

References

1994. Ultrastructure of IVM-IVF Bovine Blastocysts Vitrified after Equilibration in Glycerol 1,2-Propanediol Using 2-Step and 16-Step Procedures. Cryobiology, 31(5).
DOI: 10.1006/cryo.1994.1051

1994. The Effect of Temperature at Which Slow Cooling Is Terminated and of Thawing Rate on the Survival of One-Cell Mouse Embryos Frozen in Dimethyl Sulfoxide or 1,2-Propanediol Solutions. Cryobiology, 31(5).
DOI: 10.1006/cryo.1994.1052