Product Overview
Propylene Glycol 50% – USP Grade is a 50% aqueous solution of propylene glycol (C3H8O2, CAS 57-55-6), supplied as a thick, colorless, practically odorless liquid that mixes freely with water. Buyers reach for the 50% solution when a process calls for diluted glycol already blended with water: heat transfer loops, humectant work in formulation, and general solvent duty where the full-strength product would just be cut back anyway. Alliance Chemical is a distributor — we package and ship this product from our Taylor, Texas warehouse, and the listed pack sizes from 1 quart through 330 gallon totes are offered to order.
The buyers we see most for this item are formulators, maintenance and facilities teams running glycol loops, and purchasing managers who specify the USP Grade designation in their supplier requirements. If you need to decide fast: it is a water-white 50% PG solution, it carries no GHS hazard classification (per the product's GHS classification), and the SDS, TDS, and a lot-specific COA are available with the order.
Why This Concentration
A 50% solution removes a dilution step. Instead of receiving concentrated propylene glycol and metering in water on site — with the mixing tank, the density check, and the chance of a blend error — you receive the working strength directly. For heat transfer and freeze-point service, a roughly half-and-half glycol-water blend is a common operating point, which is why this concentration moves in drums and totes rather than only bench quantities.
The grade descriptor matters at procurement time. USP Grade is the designation buyers in pharmaceutical, cosmetic, and food-adjacent supply chains typically write into their purchasing specs, and it separates this item from technical-grade glycol in a vendor file. The grade label describes the procurement tier; review the lot COA and TDS against your own acceptance criteria to confirm fit for your application.
If your process targets a lower glycol fraction — a milder freeze-point requirement, or a formulation that needs less glycol per unit of water — the sibling Propylene Glycol 40% – USP Grade covers that point on the dilution curve with the same grade designation.
Chemical Profile
This product is a liquid: thick, colorless, and practically odorless. The 50% w/w aqueous solution has a density of 1.037 at 20 °C, so a gallon in hand weighs noticeably more than water. It is highly water-miscible — solubility is greater than or equal to 100 mg/mL at 70 °F — which is exactly the behavior that makes it useful as a water-compatible solvent and humectant. Vapor pressure is low, 0.08 mmHg at 68 °F and 0.13 mmHg at 77 °F, so it evaporates slowly and holds moisture rather than flashing off. The underlying molecule is propylene glycol (1,2-propanediol), formula C3H8O2, molecular weight 76.09, CAS 57-55-6.
Industrial Applications
Propylene glycol at 50% is a workhorse across several process roles:
-
Heat transfer and antifreeze service. Glycol-water blends depress the freezing point of a circulating loop. A 50% solution sits at a common working strength for chillers, HVAC loops, and freeze protection, ready to charge into a system without on-site blending.
-
Solvent for formulation. Propylene glycol dissolves many organics while staying fully miscible with water, which makes it a carrier solvent in pharmaceutical, cosmetic, and general formulation work.
-
Humectant. Its low vapor pressure and affinity for water let it hold moisture in a formulation — the reason it appears in food, cosmetic, and personal-care product recipes as a moisture-retention agent.
-
Cosmetic and personal-care ingredient. Formulators use it as a solvent and moisturizing component in topical products; the USP Grade designation is what those supply chains typically request.
In each case, describe your target glycol fraction first. That single number — 50% here — usually decides whether this product or a different concentration is the quicker path to your working fluid.
Handling & Storage
This is one of the easier liquids our warehouse team handles, but it still gets treated like a chemical, not a beverage. No signal word applies, and the product is not classified as hazardous under GHS based on available data (per the product's GHS classification). Standard practice still holds: wear gloves and goggles when transferring, and keep the work area ventilated.
Store it cool, dry, and out of direct sunlight in closed HDPE or glass containers. Keep it away from strong oxidizing agents and acids. The material is hygroscopic — it pulls moisture from the air — so keep containers sealed between uses to hold the blend at its stated concentration.
Hazmat & Shipping
This product has no assigned UN number, DOT hazard class, packing group, or proper shipping name (per 49 CFR 172.101). It is not regulated as a hazardous material for transport, so it does not require hazmat-specific packaging or placarding from our dock. That classification is the only thing it proves: carrier fees, routing, and delivery services are set by the carrier, not by the classification, so confirm service details on your quote. Shipping and handling guidance on this page is reviewed by Andre Taki, DOT Hazmat Specialist.
Documentation
An SDS ships with every order and is available in English, Spanish, French, and Japanese. A technical data sheet is available for the product, and a lot-specific Certificate of Analysis is available with your shipment — useful when your quality system requires traceability from receiving through production. If your vendor-qualification file needs these documents before purchase, request them with your quote.
Why Buy from Alliance Chemical
The practical case first: this one listing runs from a 1 quart bottle to a 330 gallon tote, so a formulation bench and a production floor can buy the same 50% USP Grade solution from the same supplier, with the SDS in four languages and a lot-specific COA behind every shipment. That is what repeat industrial buyers actually need — consistent material, matched paperwork, one vendor record.
Alliance Chemical has operated since 1998, and most in-stock orders ship in 1–2 business days from our Taylor, TX warehouse. Request a quick quote for drum and tote quantities, or order the smaller packs online. Ideal starting point if you are qualifying us as a supplier: order a quart or gallon, run it through your acceptance tests, then scale to drums or totes on the same spec.
