50% Propylene Glycol Inhibited

Name: Quick Facts: 50% Propylene Glycol Inhibited
Creator: Alliance Chemical
License: https://alliancechemical.com/policies/terms-of-service

Propylene Glycol

Active ingredient: propylene glycol, also known as propane-1,2-diol · 1,2-propanediol · monopropylene glycol · MPG
CAS number: 57-55-6
Formula: C3H8O2
Molecular weight: 76.09 g/mol
Concentration: 50%
Grade: Inhibited
Flash point: Not flammable (aqueous solution)
Boiling point: approx. 106 °C (222 °F) at 760 mmHg

SDS also in

Who uses it

Facilities and maintenance teams charging closed-loop HVAC systems, water-treatment and process operators running industrial chillers, and plants needing antifreeze protection for seasonally exposed equipment.

Oil & Gas
HVAC & Geothermal

Representative industry photos.

Product quick facts

CAS 57-55-6C3H8O2

50% Propylene Glycol Inhibited (CAS 57-55-6) is a 50% Inhibited-grade liquid with molecular formula C3H8O2 and a molecular weight of 76.09 g/mol. Its active ingredient, propylene glycol, is also known as propane-1,2-diol, 1,2-propanediol, monopropylene glycol and MPG. It has a flash point of Not flammable (aqueous solution). Alliance Chemical supplies this product in 7 container sizes from 1 Quart to 330 Gallon (16 pack options) with 1-2 business day shipping from Taylor, TX on in-stock orders, plus SDS and lot-specific Certificate of Analysis.

Pack sizes 7 container sizes (1 Quart to 330 Gallon) · 16 pack options
Purity / spec 50% Inhibited
Lead time In-stock orders placed by Mon-Thu 2 PM CT / Fri 12 PM CT typically ship within 1-2 business days.
Regional availability View state-by-state shipping pages

Request Bulk Quote (512) 365-6838

Stock footage.

How it ships.

Regulated products are packed, marked, and labeled for hazmat transport, from one quart to a pallet of drums.

Most stocked orders ship in 1–2 business daysOrder cutoff: Mon-Thu 2 PM CT / Fri 12 PM CT
Hazmat packing, marking, and labelingPacked by staff trained under DOT rule 49 CFR 172.704
UPS Ground for bottles, jugs, and up to three pailsLTL freight for four or more pails, drums, and totes. Liftgate on request.

Ships with
FedEx Freight
Southeastern Freight Lines

Buying for a company or agency?

Pay by card at the listed price, or order on Net 30 terms once your credit is approved. For NSN and contract requirements, send an RFQ.

CAGE code: 1LT50
UEI: DCTCZDY3BLD3
Primary NAICS: 424690
Ownership: Woman-Owned
Federal supply: DLA Supplier
Terms: Net 30 on approved credit, W-9 on request

Apply for Net 30 Email a purchase order Vendor qualification documents

Gloved hands strapping four blue chemical drums to a pallet at a warehouse loading dock — Illustration.

Safety data sheets and certificates.

Find an SDS or TDS by product name or CAS number. Certificates of analysis are free on request.

Find an SDS or COA

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Description
Product Documents
Chemical Profile

Product Overview

50% Propylene Glycol Inhibited is a ready-to-use heat-transfer and freeze-protection fluid: 50% by weight propylene glycol in deionized water with a nitrite-containing hybrid organic-acid corrosion inhibitor package. Blended by Alliance Chemical in Taylor, Texas, for closed-loop HVAC, chilled-water, hydronic and process-cooling systems.

The inhibitor package combines sodium nitrite, sodium molybdate, sodium benzoate and triethanolamine with organic-acid inhibitors, formulated for steel, cast iron, copper, brass and solder. It contains nitrite: install as a fresh fill after draining and flushing, and do not mix with phosphate-, silicate- or nitrite-free coolants.

A 50% blend is the common choice for severe-winter freeze protection of exposed piping, snow-melt and outdoor equipment.

Key Properties

Composition: Propylene glycol 49.5–50.5% by weight; corrosion inhibitor package 1.8–2.2%; deionized water balance
Propylene Glycol CAS Number: 57-55-6 (product is a mixture)
Nitrite (as NO₂): 1,200 ppm min.
Freeze Point: approx. −28°F (−33°C); specification −27°F (−32.8°C) max
pH: reported on the lot Certificate of Analysis (typically 7.0–9.0)
Reserve Alkalinity: reported on the lot Certificate of Analysis
Specific Gravity (20°C): 1.042–1.050 (calculated)
Density: approx. 1.04 g/mL (8.7 lb/gal)
Boiling Point: approx. 222°F (106°C)
Flash Point: none (aqueous solution)
Appearance: clear, colorless to pale yellow liquid; not dyed

Common Applications

Closed-Loop HVAC: heat-transfer and freeze-protection fluid for chilled-water and building glycol loops.
Hydronic Systems: seasonal freeze protection for piping and heat-transfer equipment.
Process Cooling: recirculating process and equipment cooling loops.
Standby Protection: idle or backup circulation loops that need freeze protection.

Not for food-contact, incidental-food-contact or potable-water service; not USP/NF grade. For those uses choose 50% Propylene Glycol USP Grade.

Safety Precautions

Not classified as hazardous under GHS and not regulated for transport by DOT. Contains sodium nitrite (0.2–0.4%): keep away from strong acids, which release nitrogen oxides on contact with nitrite. Avoid galvanized (zinc) surfaces. Wear chemical-resistant gloves and safety goggles during handling. Refer to the Safety Data Sheet (SDS) for full handling, storage and first-aid information.

Shipping: Not regulated as hazardous material for transport.

Benefits

Ready-to-Use Strength: Pre-blended at 50% by weight, so there is no on-site mixing. Top up with the same fluid.
Nitrite + Organic-Acid Protection: Hybrid inhibitor package for mixed-metal closed loops.
Broad Packaging Range: 1 quart to 330-gallon IBC totes.

Frequently Asked Questions About 50% Propylene Glycol Inhibited

What is 50% Propylene Glycol Inhibited used for?

It is a ready-to-use heat-transfer and freeze-protection fluid for closed-loop HVAC, chilled-water, hydronic and process-cooling systems. It is 50% by weight propylene glycol in deionized water with a nitrite-containing hybrid organic-acid corrosion inhibitor package.

What is the freeze point of 50% Propylene Glycol Inhibited?

Approximately −28°F (-33°C); the specification is −27°F (−32.8°C) maximum. Each lot's results are on its Certificate of Analysis.

Can it be mixed with other glycol coolants?

No. It contains nitrite. Install it as a fresh fill after draining and flushing the system, and do not mix it with phosphate-, silicate- or nitrite-free coolants. Avoid galvanized (zinc) surfaces.

Can it be used for food-contact or potable-water systems?

No. It is not USP/NF grade and is not for food-contact, incidental-food-contact or potable-water service. For those uses choose 50% Propylene Glycol USP Grade.

What is 50% Propylene Glycol Inhibited and what is its chemical formula?

50% Propylene Glycol Inhibited is listed under CAS 57-55-6 (PubChem reference search). The catalog formula is C3H8O2. The listed molecular weight is 76.09 g/mol. For solutions and blends, identity values may describe a constituent; consult the product SDS for composition.

What are the physical properties of 50% Propylene Glycol Inhibited?

Catalog reference information for 50% Propylene Glycol Inhibited: form: Liquid; melting point: Freeze point approx. -33 °C (-28 °F) at 50 wt% propylene glycol; boiling point: approx. 106 °C (222 °F) at 760 mmHg; flash point: Not flammable (aqueous solution); specific gravity: 1.046; reference values may describe a pure substance rather than the supplied concentration or blend. Confirm applicable conditions and specifications in the product documents; these values are not batch test results.

What grade and purity of 50% Propylene Glycol Inhibited does Alliance Chemical offer?

Alliance Chemical lists 50% Propylene Glycol Inhibited in Inhibited grade with a concentration or assay of 50%. Check the product specification for the measurement basis and acceptance limits. A grade label alone does not establish certification or suitability for a regulated application. For batch results, request a COA using the product name and lot number.

What are common industrial applications of 50% Propylene Glycol Inhibited?

Catalog industry categories for 50% Propylene Glycol Inhibited include Data Center Cooling, HVAC & Geothermal, Oil & Gas. To evaluate it for your process, compare the listed grade, concentration and product specifications with your requirements. Contact Alliance Chemical to confirm any application-specific documentation or certification before ordering.

What are the hazards of 50% Propylene Glycol Inhibited and where do I find handling guidance?

Per its GHS classification (SDS Section 2), 50% Propylene Glycol Inhibited the following hazard statements: NOT CLASSIFIED AS HAZARDOUS UNDER GHS BASED ON AVAILABLE DATA.. Product-specific first aid, fire-fighting, spill response, handling, storage, exposure controls/PPE, and disposal guidance are in SDS Sections 4-8 and 13 — always consult the SDS before use. Download the SDS.

How must 50% Propylene Glycol Inhibited waste be disposed?

Consult SDS Section 13 for disposal information for 50% Propylene Glycol Inhibited. Disposal requirements depend on the resulting waste, contamination and location. Have your site's responsible waste professional determine the appropriate waste classification and disposal method. View the SDS.

Does Alliance Chemical provide an SDS and COA for 50% Propylene Glycol Inhibited?

Search the document library for 50% Propylene Glycol Inhibited. The SDS is also available here. A sample COA describes specifications and does not establish the results for your shipment. To request a lot-specific COA or confirm document availability, contact Alliance Chemical with the product name and lot number.