설명(영) |
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Phosphorus Compounds used in cosmetics are primarily organic esters of ortho-phosphoric acid which conform to the structure:
This group also includes a few substances derived from other phosphorus containing acids.
R, R', and R'' may be alkyl groupings (e.g.,trioleyl phosphate) or Alkoxylated Fatty Alcohol groupings (e.g., Trilaneth-4 Phosphate). In true monoesters, R' and R'' may be hydrogen or an alkali-derived cation. Most commercial monoesters are in fact mixtures of mono- and diesters; again, some or all of the acidic hydrogens may be replaced by a cation, such as sodium or diethanolamine (e.g ., DEA-Oleth-10 Phosphate).
The triesters are lipophilic neutral substances, while the so-called monoesters are acidic materials, the salts of which are water-soluble surfactants. Although the phosphates are Esters, they are surprisingly stable to hydrolysis.
They are used as surfactants, wetting agents, and emulsifiers in cosmetic applications. The phosphatide Lecithin is one of the naturally occurring phosphoric acid esters. It is a phosphoric acid diester in which the hydroxyl group of a fatty acid diglyceride is esterified with a choline ester of phosphoric acid. |