PROPYLENE GLYCOL- ▸ Functional fluids: Antifreeze, de-icing, and heat-transfer fluid
- ▸ Humectant: Moisture-retention agent in formulated products
- ▸ Solvent: Solvent for paints, plastics, flavors, and fragrances
- ▸ Resins: Raw material for unsaturated polyester resins
- ▸ Technical Data Sheet (TDS) PDF · TDS
- ▸ Typical Certificate of Analysis (CoA) PDF · COA
Values shown are typical for the current commercial grade. A lot-specific Certificate of Analysis accompanies every shipment; the grade-specific SDS is available on request.
A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.
Request SDS →Propylene glycol (mono-propylene glycol, MPG or PG; INCI Propylene Glycol; CAS 57-55-6) is a clear, colorless, nearly odorless, viscous diol — 1,2-propanediol. It is hygroscopic and fully water-miscible, which is what makes it one of the most versatile workhorses in the chemical industry: a humectant, solvent, carrier and heat-transfer / antifreeze fluid all at once. The grade is the key buying decision — a pharmacopoeial/food grade (USP/EP) for food, pharmaceutical and personal-care use, or an industrial/technical grade for antifreeze, coatings and chemical synthesis. Identity: PubChem.
What is propylene glycol?
Propylene glycol is 1,2-propanediol, a small dihydric alcohol. Its two hydroxyl groups make it strongly water-attracting (hygroscopic) and fully miscible with water and many organic solvents, while its low volatility and low freezing point of the water mixtures make it useful as a heat-transfer and antifreeze fluid. It is the lower-toxicity counterpart to ethylene glycol, which is why it is the diol chosen for systems with potential food contact or occupational exposure. Food- and pharmaceutical-grade material is supplied to the USP/EP monograph.
Grades
Specify the grade for the duty. USP/EP (pharmacopoeial) grade — also the food grade — is used in food, beverage, flavor, pharmaceutical and personal-care applications under its monograph. Industrial / technical grade is used for antifreeze and heat-transfer fluids, deicing, coatings, unsaturated polyester resin and chemical synthesis. Confirm the grade, assay, water content and any monograph requirement on the RFQ; the CoA documents the lot.
Applications by sector
Food & beverage (USP/food grade). Humectant and moisture-retainer, and a carrier/solvent for flavors, colors and extracts. Pharmaceutical & personal care (USP grade). Humectant, solvent and carrier in topical, oral and cosmetic formulations; it holds water in the formula and dissolves actives. Antifreeze, heat-transfer & deicing. The lower-toxicity alternative to ethylene glycol in HVAC and chiller loops, food- and beverage-plant systems, RV/marine antifreeze, and aircraft and runway deicing fluids. Industrial & coatings. Solvent and coalescent, hydraulic and brake-fluid component, humectant in adhesives and inks, and a feedstock for unsaturated polyester resins and plasticizers. These describe function and use, not health claims.
Propylene glycol vs ethylene glycol vs glycerin
All three are humectant/antifreeze-capable polyols, but they are not interchangeable. Propylene glycol is the lower-toxicity diol used where food contact or exposure matters; ethylene glycol gives slightly better heat-transfer economics but is acutely toxic and restricted to closed industrial systems; glycerin (glycerol) is a triol, a stronger humectant with higher viscosity, often chosen for food and personal care. Pick by toxicity profile, freeze depression needed, viscosity and grade.
Handling and documentation
Propylene glycol is a stable, low-volatility liquid; consult the Safety Data Sheet (SDS) for handling and storage. Each lot ships with a Certificate of Analysis (CoA); USP/EP grades carry the monograph documentation.
Bulk supply and RFQ
RawSource supplies propylene glycol in bulk — drums, totes, IBCs and bulk — from domestic US stock to food, pharmaceutical, personal-care, HVAC/antifreeze, coatings and industrial buyers. Specify USP/EP/food or industrial grade, target quantity and ship-to for a current quote with CoA and SDS. Related polyols: dipropylene glycol, glycerin.
Typical Properties
Typical reference values, not a specification; the Certificate of Analysis (CoA) for the lot governs.
| Property | Typical Value |
|---|---|
| Chemical Name | Propylene glycol (1,2-propanediol, MPG) |
| INCI Name | Propylene Glycol |
| CAS / EC number | 57-55-6 / 200-338-0 |
| Molecular Formula | C3H8O2 |
| Molecular Weight | ~76.1 g/mol |
| Appearance | Clear, colorless, viscous liquid |
| Odor | Practically odorless |
| Solubility | Miscible with water and many organic solvents; hygroscopic |
| Density (20 °C) | ~1.036 g/cm³ |
| Grades | USP/EP (pharma/food) and industrial/technical |
Regulatory & registration requirements
- TSCA (US):
- REACH (EU):
- EC number: 200-338-0
Source: EPA TSCA Inventory (July 2025 release) · ECHA CHEM — retrieved 2026-07-12
Solutions Using This Product
Process-solution guides on this site that specify this chemistry:
- Coalescing Agents for Waterborne Coatings (Glycol Ethers, Diacetone Alcohol) (Coatings & Construction)
- Low-VOC Solvents & Glycol Ethers for Coatings (Coatings & Construction)
- Low-VOC Glycol Ethers & Bio-Solvents for Cleaners (Home & Industrial Care)
Frequently Asked Questions
What is propylene glycol used for?
Propylene glycol (CAS 57-55-6) is used as a humectant, solvent and carrier in food, pharmaceutical and personal-care products (USP/food grade), and as an antifreeze and heat-transfer fluid, deicing fluid, coatings solvent/coalescent, and chemical intermediate (industrial grade).
What is the difference between USP and industrial propylene glycol?
USP/EP (pharmacopoeial) grade meets the monograph for food, pharmaceutical and personal-care use. Industrial/technical grade is used for antifreeze, heat-transfer, deicing, coatings and synthesis. They differ in purity, documentation and permitted use; specify the grade on the RFQ.
Is propylene glycol the same as ethylene glycol?
No. Both are antifreeze-capable diols, but propylene glycol (1,2-propanediol) is the lower-toxicity material used where food contact or exposure is a concern, while ethylene glycol is acutely toxic and restricted to closed industrial systems. They are not interchangeable.
Is propylene glycol an antifreeze?
Yes — industrial-grade propylene glycol is widely used as a lower-toxicity antifreeze and heat-transfer fluid in HVAC, food-plant, RV/marine and deicing applications. Use the industrial grade for these systems, not the food grade.
What is the CAS number and formula of propylene glycol?
Propylene glycol is CAS 57-55-6 (EC 200-338-0; PubChem CID 1030), molecular formula C3H8O2, ~76.1 g/mol. The CoA documents the grade and assay.
How is bulk propylene glycol supplied and quoted?
RawSource supplies it in drums, totes, IBCs and bulk from domestic US stock, with CoA and SDS per lot. Pricing is quote-based on grade, volume and freight; submit an RFQ with your target quantity and ship-to.
What is the REACH and TSCA regulatory status of Propylene Glycol (MPG, PG)?
Propylene Glycol (MPG, PG) (CAS 57-55-6) is subject to U.S. TSCA Inventory requirements; supplying it into the EU requires valid REACH registration ((EC) No 1907/2006). RawSource cannot verify a third-party supplier's registrations — buyers should require documented TSCA and REACH compliance for their jurisdiction and volume (EC 200-338-0).