, is a viscous colourless liquid which is nearly odourless but possesses a faintly sweet taste..
PROPYLENE GLYCOL: A MULTI-TALENT
With its unique combination of properties propylene glycol supports many uses.
- It serves as a solvent
- connects and stabilises insoluble fluids (emulsifier)
- helps to bind and transport other substances (excipient)
- holds and dissolves active ingredients equally in a medium
- attracts/holds water/moisture (hygroscopic)
- reduces the freezing point
- increases the boiling point
- offers outstanding stability with high flash and boiling points
The propylene glycol molecule is chemically neutral, i.e. it usually does not react with other substances. This is a particularly helpful property in the combining of contrasting chemicals, for example in a perfume, to create a single, homogeneous fluid.
.Application as a Coolent :
Like ethylene glycol, propylene glycol is able to lower the freezing point of water,
and so it is used as aircraft de-icing fluid.
Water-propylene glycol mixtures dyed pink to indicate the mixture is relatively nontoxic are sold under the name of RV or marine antifreeze
. Propylene glycol is frequently used as a substitute for ethylene glycol in low toxicity
, environmentally friendly automotive antifreeze
It is also used to winterize the plumbing systems in vacant structures.As A Humectant, Sovent & Preservative :
Propylene glycol is used as a humectant (E1520), solvent, and preservative in food and for products. where it is vaporized in the atomizer.
Propylene glycol is also used in various edible items such as coffee-based drinks, liquid sweeteners, ice cream, whipped dairy products and soda.
Vaporizers used for delivery of pharmaceuticals or personal-care products often include propylene glycol among the ingredients.Propylene glycol is used as a solvent in many pharmaceuticals,
including oral, injectable and topical formulations, such as for which are insoluble in water. Used to produce polyurethanes :
propylene glycol produced is used as chemical feedstock for the production of unsaturated polyester resins. In this regard, propylene glycol reacts with a mixture of unsaturated maleic anhydride and isophthalic acid to give a copolymer. This partially unsaturated polymer undergoes further crosslinking to yield thermoset plastics. Related to this application, propylene glycol reacts with propylene oxide to give oligomers and polymers that are used to produce polyurethanes.As a veterinary medicine :
Propylene glycol is used in veterinary medicine as an oral treatment for hyperketonaemia in ruminants. Glucose, which can be used in non-ruminants for this purpose, is not effective due to its consumption by the resident microbes of the rumen. Propylene glycol is partially metabolized in the rumen to propionate which can be used as an energy source. The remainder is absorbed into the bloodstream and used by the liver for gluconeogenesis.
As a stable homogeneous fluid :
By emulsifying active ingredients, which otherwise would not mix, propylene glycol helps to create a stable homogeneous fluid allowing for the intended final product, such as a face cream or shampoo to perform its function.