Chemical laboratory

Propylene Glycol

Versatile Industrial Solvent and Chemical Intermediate

  • CAS 57-55-6
  • Formula C₃H₈O₂
  • Flash Pt 99°C
  • Density 1.036 g/cm³
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Physical & Chemical Properties

Property Value Unit
Boiling point 188.2°C °C
Flash point 99°C °C
Density 1.036 g/cm³ g/cm³
Solubility Miscible with water -
Ph 6.0-8.0 (50% aqueous solution) -
Molecular weight 76.09 g/mol g/mol
Melting point -59°C °C
Vapor pressure 0.13 mmHg at 20°C mmHg
Autoignition temp 371°C -
Appearance Clear, colorless, viscous liquid -
Odor Slightly sweet -
Vapor density 2.62 (air = 1) g/cm³

Overview

Propylene Glycol (C₃H₈O₂) is a clear, colorless, viscous liquid with a slightly sweet odor and excellent solubility properties. This versatile diol compound serves as a critical ingredient across multiple industries, from pharmaceuticals and cosmetics to industrial manufacturing and food processing. With its unique combination of low toxicity, antimicrobial properties, and excellent solvency characteristics, propylene glycol has become an indispensable component in countless formulations and applications.

Key Applications

  • Industrial Solvent: Excellent solvent for resins, dyes, and various organic compounds in manufacturing processes
  • Antifreeze and Heat Transfer: Non-toxic alternative to ethylene glycol in automotive and HVAC systems, particularly where human contact is possible
  • Pharmaceuticals and Cosmetics: Humectant and carrier for active ingredients in topical medications, lotions, and personal care products
  • Food Industry: FDA-approved food additive used as a humectant, solvent, and preservative in processed foods and beverages

Safety & Handling

With a flash point of 99°C and autoignition temperature of 371°C, propylene glycol presents relatively low fire hazards under normal conditions. Standard PPE including safety glasses, gloves, and protective clothing should be worn when handling. Ensure adequate ventilation in work areas to minimize vapor exposure. While generally recognized as safe, avoid prolonged skin contact and inhalation of vapors.

Storage & Shelf Life

Store propylene glycol in tightly sealed containers in a cool, dry area away from heat sources and incompatible materials. Stainless steel, aluminum, or approved plastic containers are recommended. Maintain storage temperatures below 25°C for optimal shelf life. Avoid contact with strong oxidizing agents and bases. Properly stored material maintains quality for 2-3 years from manufacture date.

Why Alliance Chemical

Alliance Chemical delivers Propylene Glycol with same-day shipping from our Taylor, Texas facility. We offer flexible shipping options including UPS, LTL, and FTL to meet your volume requirements. Every shipment includes comprehensive Safety Data Sheets (SDS) and Certificates of Analysis (COA) to ensure product quality and regulatory compliance for your operations.

Shipping & Availability

Parcel Shipping

UPS Ground supports pints, quarts, and most 1-gallon packages nationwide.

LTL Freight

5-gallon pails, drums, and totes move via LTL carriers such as ABF Freight, SEFL, Saia, and XPO.

Full Truckload

FTL available for palletized bulk orders. Competitive freight rates.

Local Pickup

Will-call pickup available at our Taylor, TX warehouse for Texas customers.

SDS, COA, and TDS available for every product • Most orders ship in 1-2 business days from Taylor, TX

Buy Propylene Glycol by State

Select your state for local shipping times, industry applications, and ordering details.

Available Sizes

Propylene Glycol Inhibited ACS Grade - 1 Quart

1 Quart

$25.00

 Propylene Glycol Inhibited ACS Grade - 1 Gallon

1 Gallon

$60.00

 Propylene Glycol Inhibited ACS Grade - 5 Gallon Pail

5 Gallon Pail

$200.00

 Propylene Glycol Inhibited ACS Grade - 15 Gallon Drum

15 Gallon Drum

$520.00

 Propylene Glycol Inhibited ACS Grade - 55 Gallon Drum

55 Gallon Drum

$2,000.00

 Propylene Glycol Inhibited ACS Grade - 275 Gallon IBC Tote

275 Gallon IBC Tote

$9,000.00

 Propylene Glycol Inhibited ACS Grade - 330 Gallon IBC Tote

330 Gallon IBC Tote

$10,400.00
View all sizes →

Frequently Asked Questions

What is propylene glycol (CAS 57-55-6) and what is it used for?
Propylene glycol (1,2‑propanediol), CAS 57-55-6, formula C3H8O2, is a colorless, hygroscopic, water‑miscible organic liquid used as a solvent, heat transfer/antifreeze component, and reagent in industrial and laboratory processes. It is commonly employed where low volatility, miscibility with water, and stability are required.
How should I store propylene glycol and what is its typical shelf life?
Store propylene glycol in a cool, dry, well‑ventilated area away from strong oxidizers and direct sunlight, in tightly closed containers to avoid contamination. When kept sealed and uncontaminated, shelf life is typically 1–3 years depending on grade and supplier—refer to the product Certificate of Analysis for exact expiry guidance.
What safety precautions and personal protective equipment (PPE) are recommended for handling propylene glycol?
Use chemical‑resistant gloves, safety goggles and standard protective clothing to avoid prolonged skin contact or eye exposure; ensure adequate ventilation to minimize inhalation of mists. Although considered low‑acute‑toxicity, it can cause irritation—follow the supplier SDS for first‑aid, spill response and exposure limits.
How do 50%, 40%, and 30% propylene glycol concentrations differ and how do I choose the right one?
Higher concentrations of propylene glycol provide greater freezing‑point depression, higher viscosity and slightly higher density; lower concentrations are less viscous and less effective for freeze protection. Choose concentration based on required freeze protection, heat‑transfer performance and system compatibility, and confirm whether percentages are w/w or v/v on the product data sheet.
What documentation is provided with propylene glycol deliveries (SDS, COA, TDS)?
Suppliers typically provide a Safety Data Sheet (SDS), Certificate of Analysis (CoA) and Technical Data Sheet (TDS) with each shipment; additional regulatory or quality documents can be supplied on request. Verify lot‑specific analytical data on the CoA for purity, water content and any specified impurities.
How is propylene glycol shipped and what packaging options are available?
Propylene glycol is commonly shipped in drums (200 L), intermediate bulk containers (IBC, ~1,000 L) and bulk tankers; sample packs and custom packaging are often offered for lab use. While it is not classified as a dangerous good in many jurisdictions, always confirm transport classification and labeling with local regulations and provide the SDS to carriers.
Is propylene glycol compatible with metals, plastics and elastomers used in industrial systems?
Propylene glycol is generally compatible with common metals such as stainless steel, carbon steel and copper, and with plastics like HDPE and polypropylene. It can attack or cause stress cracking in some elastomers, coatings and certain engineering plastics—perform material compatibility checks or consult supplier compatibility charts for seal and gasket selection.
What are the key technical specifications for propylene glycol (CAS 57-55-6)?
Key identifiers: Propylene glycol (1,2‑propanediol), CAS 57-55-6, C3H8O2; physical properties: colorless, viscous, water‑miscible liquid with approximate boiling point 188°C, melting point −59°C and density ~1.03 g/cm³ (20°C). Typical product specs vary by grade and concentration—refer to the TDS/CoA for purity, water content, refractive index and other analytical limits.
Which industries and applications commonly use propylene glycol in industrial and laboratory settings?
Propylene glycol is used in HVAC and heat‑transfer systems, industrial process fluids, de‑icing/anti‑icing formulations, analytical and preparative laboratory applications, and as a solvent for specialty chemical formulations. Its properties make it useful wherever a low‑volatility, water‑miscible carrier or freeze‑point depressant is needed.
How can I purchase propylene glycol (50%, 40%, 30%) and what is typical availability and lead time?
Propylene glycol at 50%, 40% and 30% concentrations is widely available from chemical distributors and manufacturers in drums, IBCs and bulk; many suppliers can provide small sample quantities for lab use. Typical lead times range from immediate stock shipment to a few weeks for larger bulk orders—contact suppliers for price, minimum order quantities and current inventory.

Documentation & Downloads

Safety Data Sheet
SDS / MSDS
View Sample COA
Certificate of Analysis
Technical Data Sheet (TDS)
Available for all products

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