Product Overview
Propylene Glycol USP Grade (CAS 57-55-6) is a thick, colorless, practically odorless liquid that mixes readily with water. It is the pharmacopeial grade of 1,2-propanediol — the grade buyers specify when a formulation, usp-adjacent process, or personal-care line demands documented purity rather than usp-grade material. we distribute it in our Taylor, TX warehouse and ship it daily, from single quarts for bench and formulation work up to 275 and 330 gallon totes for production lines.
Typical buyers are formulation and QC leads in usp and personal-care manufacturing, usp-industry process engineers who need a humectant, and facilities teams running glycol-based heat-transfer or de-icing systems where a higher-purity fluid is preferred.
Why This Concentration
This is undiluted USP Grade propylene glycol. Buying it neat gives you control: you dilute to whatever ratio your process calls for, whether that is a heat-transfer loop, a humectant blend, or a solvent system. If your application is a coolant or antifreeze circuit, you will typically cut it with water on site to hit your target freeze protection — mixing is straightforward because the product is fully water-miscible.
The grade decision matters more than the concentration here. USP Grade is the right call when your downstream use touches usp, usp, or cosmetic supply chains and your auditors expect pharmacopeial-grade inputs with lot documentation. If your use is purely usp — a closed-loop coolant, for example — USP Grade still works; you are simply paying for purity headroom your process may not require.
Chemical Profile
Propylene glycol is a diol with the formula C3H8O2, a molecular weight of 76.09, and CAS number 57-55-6. It presents as a thick, colorless liquid with practically no odor. Density is 1.04 at 68 °F, so it is slightly denser than water and will sink before it dissolves — and dissolve it does, with water solubility of 100 mg/mL or greater at 70 °F and full miscibility in practice. Vapor pressure is low: 0.08 mmHg at 68 °F and 0.13 mmHg at 77 °F, which is why the liquid evaporates slowly and holds moisture well — the property behind its use as a humectant.
USP Applications
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USP solvent:dissolves and carries active ingredients in drug formulations where a pharmacopeial-grade excipient is specified.
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USP-industry humectant:retains moisture in usp formulations, keeping products from drying out during storage and distribution.
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Antifreeze and heat transfer:lowers the freeze point of water-based coolant loops and de-icing solutions; commonly chosen for systems where a lower-toxicity glycol is preferred over ethylene glycol.
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Cosmetics and personal care:functions as a solvent and moisture-carrier in lotions, creams, and other formulations.
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Analytical work:used as a mobile-phase component in reversed-phase chromatography for separating organic compounds.
In every one of these roles the working properties are the same: high water miscibility, low vapor pressure, and strong moisture affinity. What changes is the documentation requirement — and that is what USP Grade covers.
Handling & Storage
This product is not classified as hazardous under GHS based on available data (per the product's GHS classification), and it carries no signal word. That makes it one of the easier liquids in our warehouse to handle, but standard usp practice still applies: wear gloves and goggles, and keep ventilation adequate when transferring.
Store it cool, dry, and out of direct sunlight in compatible containers — HDPE or glass both work; that is how we pack it. Keep it away from strong oxidizing agents. Because propylene glycol is hygroscopic, keep containers closed when not in use; an open drum will slowly pull moisture from the air and drift off spec.
Hazmat & Shipping
Canonical transport status is not regulated. Review the current SDS and carrier requirements before shipment.
Documentation
A Safety Data Sheet ships with every order, available in English, Spanish, French, and Japanese. A lot-specific Certificate of Analysis is available for the material you receive, and a USP Data Sheet is available for spec review before you buy. If your quality system requires documents up front, ask — we send them before the freight moves.
Why Buy from Alliance Chemical
We are a stocking distributor, not a broker. This product sits in our Taylor, TX warehouse and ships daily — quarts to full totes — packed by a team that handles regulated and non-regulated chemicals side by side, so packaging discipline is the same either way. Every order leaves with its SDS, lot-traceable paperwork is standard, and our shipping practices are reviewed by a DOT Hazmat Specialist. If you are scaling from bench quantities to drum or tote volume, you deal with the same warehouse and the same material.
Comparing suppliers?
Before you compare quotes, readHow to Choose a Bulk Chemical Supplier— the four documents to demand, how to pick the grade your process actually needs (and where buyers overpay), why you should comparedeliveredprices rather than unit prices, and the red flags worth walking away from.
