Propylene Glycol (CAS 57-55-6), chemically identified as 1,2-propanediol, is a versatile aliphatic alcohol functioning as a solvent, humectant, and heat transfer medium in industrial functional fluid formulation and polymer production. This clear, viscous liquid, also technically referred to as 1,2-dihydroxypropane or methylethyl glycol, serves as a critical intermediate in the synthesis of unsaturated polyester resins and acts as a safe antifreeze agent in cooling systems where low toxicity is required. We provide bulk supply of this industrial raw material with competitive factory pricing to support diverse manufacturing sectors. Our logistics network ensures reliable delivery, making MSDS, TDS, COA available alongside customized specifications to meet specific purity or grade requirements.
Propylene glycol CAS 57-55-6
- CAS: 57-55-6
- Synonyms: 1,2-propanediol, 1,2-dihydroxypropane, methylethyl glycol, alpha-propylene glycol, monopropylene glycol
- Einecs: 200-338-0
- Molecular Formula: C3H8O2
- Grade: Industrial / Technical / USP / Food grade
- Package: 215 kg steel drums, 1,050–1,100 kg IBC tanks, or bulk / ISO tank as required
Product Description
Propylene glycol (PG) is a clear, nearly odorless, hygroscopic liquid widely used as a solvent, humectant and intermediate in food, pharmaceutical, cosmetic and industrial formulations. Anhui HC-T / IndustroChem supplies propylene glycol with stable quality, competitive factory prices and full technical support for international customers.
📧 Email: info@industrochem.com – Contact our team for the latest bulk price, COA and sample support.
Physicochemical Properties
| Item | Value / Specification* |
|---|---|
| Chemical name | Propylene glycol |
| CAS No. | 57-55-6 |
| Einecs No. | 200-338-0 |
| Molecular formula | C₃H₈O₂ |
| Molecular weight | 76.09 g/mol |
| Grade | Industrial / Technical / USP / Food grade (on request) |
| Appearance | Colorless, transparent, almost odorless viscous liquid |
| Assay (propylene glycol) | ≥ 99.5 wt% |
| Water content | ≤ 0.2 wt% |
| Color (Pt–Co) | ≤ 10 |
| Density (20 °C) | 1.035–1.040 g/cm³ |
| Boiling point (101.3 kPa) | 188–189 °C |
| Melting point | approx. −59 °C |
| Flash point (closed cup) | approx. 99 °C |
| Refractive index (n²⁰ᴰ) | 1.431–1.433 |
| Solubility | Miscible with water, ethanol, acetone; low in many oils |
Applications
1. Food & Flavor Industry
- Used as a humectant and solvent in food, flavors and fragrances
- Carrier for colorants, antioxidants and other functional additives
- Helps improve texture, moisture retention and stability in many processed foods
2. Pharmaceutical & Personal Care
- Widely used as an excipient in oral, topical and injectable formulations
- Solvent and co-solvent for active ingredients with limited water solubility
- Moisturizing agent in skin-care, hair-care, toothpaste, mouthwash and other products
- Good skin feel and compatibility with typical cosmetic ingredients
3. Industrial Chemicals & Resins
- Important intermediate for unsaturated polyester resins, plasticizers and surfactants
- Used in coatings, inks and cleaning agents as a low-volatility solvent
- Component in various chemical formulations requiring high purity glycols
4. Deicing & Heat Transfer Fluids
- Base fluid for aircraft deicing liquids, automotive antifreeze (low-toxicity grade)
- Heat transfer medium in HVAC, solar systems, industrial cooling loops
- Offers a safer alternative to ethylene glycol where lower toxicity is required
5. Other Uses
- Humectant and softener in tobacco, paper and textiles
- Carrier in agrochemical formulations and household products
If you have a special application, our technical team can help verify compatibility and recommend a suitable grade and specification.
For related glycol-based raw materials with different solvent or formulation profiles, see Tripropylene Glycol and Dipropylene Glycol Monomethyl Ether.
Storage Conditions
- Store in a cool, dry and well-ventilated warehouse
- Keep containers tightly closed to avoid moisture uptake and contamination
- Recommended storage temperature: 5–40 °C
- Protect from direct sunlight, heat sources and ignition sources
- Keep away from strong oxidizing agents and strong acids
- Use carbon steel or stainless steel tanks, drums or IBCs with proper inner coating if needed
Under proper storage, propylene glycol remains stable for an extended period; please follow the shelf life and storage advice on the COA/label.
Safety Precautions
Propylene glycol is generally considered to have low acute toxicity, but correct handling is still essential in industrial environments:
- Avoid direct contact with eyes and prolonged contact with skin
- Wear appropriate gloves, goggles and work clothing
- Provide adequate ventilation when handling large volumes or heated product
- Prevent formation of fine mist or aerosols; avoid inhalation of vapors/mist
- In case of eye contact: rinse with plenty of water for at least 15 minutes and seek medical advice if irritation persists
- In case of skin contact: wash with soap and water; remove contaminated clothing
- In case of accidental ingestion: rinse mouth and seek medical attention if needed
FAQ - Technical & Supply Chain
-
Q:
What is Propylene Glycol CAS 57-55-6?
A: Propylene Glycol, also called 1,2-propanediol or monopropylene glycol, is a clear, nearly odorless, hygroscopic liquid with the molecular formula C3H8O2. It is widely used as a solvent, humectant, heat-transfer fluid, and chemical intermediate. -
Q:
How is Propylene Glycol different from Ethylene Glycol?
A: Propylene Glycol has an additional methyl group compared with ethylene glycol and is much less acutely toxic. For this reason, food, pharmaceutical, cosmetic, and low-toxicity antifreeze applications use propylene glycol rather than ethylene glycol. -
Q:
What grades of Propylene Glycol are available?
A: Industrial/technical, food, USP, and pharmaceutical-grade material can be supplied. Food and pharmaceutical applications normally require USP, food-grade, or pharmacopoeia-compliant material, while industrial uses may use technical grade. -
Q:
What are the main applications of Propylene Glycol?
A: It is used in unsaturated polyester resin production, antifreeze and heat-transfer fluids, food additives, flavors, fragrances, cosmetics, personal care products, and pharmaceutical formulations. It also acts as a carrier or solvent for many active ingredients and colorants. -
Q:
Why is Propylene Glycol used in unsaturated polyester resins?
A: Propylene Glycol is one of the glycol monomers used in polyester polycondensation. The choice and ratio of glycol affect resin flexibility, hardness, water resistance, reactivity, and processing behavior, making PG important for balancing resin performance. -
Q:
How should Propylene Glycol be stored and handled?
A: Keep it in tightly closed, compatible containers in a cool, dry, well-ventilated area away from strong oxidizers and ignition sources. Use liquid-chemical handling controls, suitable PPE, and protect material from moisture contamination.
Ordering & Documentation
Key information for document requests, quotations, and supply planning.
Documents
COA, TDS, SDS/MSDS and packing details are available on request.
Quotation
Send the CAS number, grade, quantity, packing preference and destination.
Sample & Supply
Support is available for samples, trial orders, bulk and repeat supply.
Storage & Shipping
Product-specific conditions are confirmed before order.
