Ethylene Glycol vs Propylene Glycol
Comprehensive comparison of Ethylene Glycol and Propylene Glycol including physical properties, applications, safety considerations, and pricing. Alliance Chemical supplies both chemicals in various grades and concentrations.
Quick Comparison Summary
Physical & Chemical Properties Comparison
| Property | Ethylene Glycol | Propylene Glycol | Key Difference |
|---|---|---|---|
| Boiling Point | 197.3 °C | 188.2°C | Ethylene Glycol boils 9.1°C higher |
| Flash Point ⚠️ | 111 °C | 99°C | Propylene Glycol is more flammable |
| Density | 1.113 g/cm³ | 1.036 g/cm³ | Ethylene Glycol is denser |
| Water Solubility | Miscible with water | Miscible with water | Both fully water soluble |
| pH | 7.0 | 6.0-8.0 (50% aqueous solution) | Similar pH range |
| Molecular Weight | 62.07 g/mol | 76.09 g/mol | Propylene Glycol is heavier molecule |
| Melting Point | -13 °C | -59°C | Ethylene Glycol melts 46°C higher |
| Vapor Pressure | 0.06 mmHg at 20 °C | 0.13 mmHg at 20°C | Propylene Glycol is more volatile |
| Auto-ignition Temp ⚠️ | 410 °C | 371°C | Propylene Glycol auto-ignites at lower temp |
| Vapor Density | 2.14 (air = 1) | 2.62 (air = 1) | Propylene Glycol vapors sink more |
| Appearance | Clear, colorless liquid | Clear, colorless, viscous liquid | |
| Odor | Odorless | Slightly sweet |
Data sourced from PubChem (NIH), OSHA Technical Guidelines, and Alliance Chemical laboratory analysis. Last verified April 2026.
Applications & Use Cases
Ethylene Glycol Best For:
- Antifreeze
- Engine coolant
- Heat transfer fluid
- Industrial solvent
- Plasticizer feedstock
Propylene Glycol Best For:
- Industrial solvent
- Antifreeze
- Humectant
- Chemical intermediate
- Heat transfer fluid
Choosing Between Them
The right choice depends on your specific application, required purity, and handling capabilities. Contact our team for guidance on which chemical best fits your needs.
Safety & Handling Comparison
Storage Requirements
Always store in original containers in a cool, well-ventilated area per NFPA 30 guidelines. Refer to each product's SDS for specific storage temperature ranges and incompatible materials.
PPE Requirements
At minimum: chemical-resistant gloves, safety goggles, and adequate ventilation per OSHA 29 CFR 1910.132-138. Check each SDS below for chemical-specific PPE requirements.
Fire Hazard
Propylene Glycol has a lower flash point and requires extra fire precautions.
Safety Data Sheets (SDS)
Which Chemical Should You Choose?
Decision Snapshot
| Decision Factor | Better Fit | Why |
|---|---|---|
| Evaporation Profile | Propylene Glycol | Lower boiling point supports faster flash-off. |
| Fire Safety Margin | Ethylene Glycol | Higher flash point generally reduces ignition risk in handling and storage. |
| Application Breadth | Propylene Glycol | Compares distinct listed use cases to avoid generic recommendations. |
| Purity Flexibility | Standard grades | Based on availability of 99%+ concentration options in current product metadata. |
Choose Ethylene Glycol if:
Best for: Heat-transfer and antifreeze duty where maximum thermal performance matters.
Watch-out: Not ideal where reduced-toxicity formulations are a purchasing requirement.
- You specifically need support for engine coolant applications.
- You specifically need support for plasticizer feedstock applications.
- You need a higher-boiling solvent that stays in-process longer.
- Fire-risk controls are a priority and you prefer the higher flash-point option.
Choose Propylene Glycol if:
Best for: Applications prioritizing lower toxicity and broader handling compatibility.
Watch-out: Can deliver lower heat-transfer efficiency than ethylene glycol systems.
- You specifically need support for humectant applications.
- You specifically need support for chemical intermediate applications.
- You want a faster-evaporating solvent for quick-dry production steps.
- You can manage stricter flammable-liquid controls for lower flash-point performance.
Commercial & Fulfillment Snapshot
Built for purchasing teams that need predictable dispatch, compliant documentation, and freight flexibility from parcel to full truckload.
| Procurement Advantage | Ethylene Glycol | Propylene Glycol |
|---|---|---|
| Grade & Concentration Coverage | multiple concentration options by application with industrial/lab procurement support. | 50% to 30% with industrial/lab procurement support. |
| Packaging Depth | 1 Quart to 330 Gallon IBC Tote for parcel, pallet, and truckload planning. | small packs through bulk freight quantities for parcel, pallet, and truckload planning. |
| Dispatch SLA | Order by 1 PM CT (Mon-Thu) or noon CT Friday for same-business-day outbound from Taylor, TX. | Order by 1 PM CT (Mon-Thu) or noon CT Friday for same-business-day outbound from Taylor, TX. |
| Freight Optionality | UPS Ground for small packs plus LTL/FTL lanes through ABF, SEFL, Saia, XPO, and partner carriers. | UPS Ground for small packs plus LTL/FTL lanes through ABF, SEFL, Saia, XPO, and partner carriers. |
| Compliance Readiness | SDS ready now; COA/TDS support available pre-PO and post-order. | SDS ready now; COA/TDS support available pre-PO and post-order. |
| Bulk Procurement CTA | Request bulk quote or call (512) 365-6838. | Request bulk quote or call (512) 365-6838. |
Need Help Deciding? Our technical team can help you choose the right chemical for your specific application. Email sales@alliancechemical.com for expert guidance.
Request Bulk Quote
Share your quantity, pack size, and destination. We will reply with pricing, freight options, and documentation.
Prefer email? sales@alliancechemical.com
Ready to Order?
Alliance Chemical supplies both Ethylene Glycol and Propylene Glycol in various grades and package sizes.