Product Introduction

Propylene glycol is a synthetic liquid substance that absorbs water. It is labeled as an alcohol, but it is safe to use in cosmetic and food products. It is a small organic alcohol commonly used as a solvent, humectant, and emollient, in a wide range of cosmetic, pharmaceutical, and food products.[1] Propylene glycol is odorless, colorless, and possesses a slightly sweet taste. It is miscible with water, alcohol, and many other organic solvents.

Production Process

Propylene glycol is commercially produced mainly via the chemical hydration of propylene oxide. This process can be achieved through non-catalytic or catalytic methods. The non-catalytic method involves reacting propylene oxide with a large excess of water at high temperatures and pressures [2]. Catalytic methods employ ion exchange resins or other catalysts to enhance the reaction rate and selectivity, generally performed, at lower temperatures [3]. Plant-based propylene glycol can be produced by the fermentation of sugars or glycerol, followed by chemical conversion processes.

Efficacy and Function

Propylene glycol functions as a humectant in cosmetics by attracting moisture to the skin. It is a viscosity-decreasing agent, solvent, and emollient. It helps to improve the texture and feel of formulations. Propylene glycol can also enhance the penetration of other ingredients into the skin [4]. It is valued for its ability to blend immiscible ingredients, creating a stable and uniform product.

Application Scenarios

Propylene glycol is found in a variety of cosmetic and personal care products, like moisturizers, lotions, shampoos, conditioners, and makeup. It is also used in pharmaceutical formulations, such as topical creams, ointments, and solutions. In the food industry, it acts as a solvent for food colors and flavors, and is also used as a humectant to maintain moisture in baked goods [5]. It can be used in antifreeze solutions and as a de-icing agent.

Packaging and Transportation

Propylene glycol is typically packaged in plastic drums, IBCs (Intermediate Bulk Containers), or in bulk tanks, depending on the quantity. The containers are usually made of high-density polyethylene (HDPE) or steel. During transportation, containers must be properly sealed and labeled according to transportation regulations. Propylene glycol is not classified as a hazardous material, so it does not require special handling. It should be stored in a cool, dry, and well-ventilated area away from heat and ignition sources.

Citations

[1] National Center for Biotechnology Information (2024). PubChem Compound Summary for CID 1030, Propylene glycol. Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/Propylene-glycol
[2] Qiu, F., Li, Y., Wang, J., Shi, J., & Chang, F. (2020). Production of propylene glycol from cellulose over Ni/MgO–ZrO2 catalyst in supercritical water. Bioresource Technology, 314, 123732.
[3] Suppliers, I. C. I. Process for manufacturing glycol. US2451485A, 1948.
[4] Loden, M., & Andersson, A. C. (2016). Effect of humectants on the barrier properties of human skin. International journal of cosmetic science, 38(6), 549-552.
[5] O’Brien Nabors, D. (2012). Food Additives: Chemical and Functional Properties. John Wiley & Sons.

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