Hydrolysis-Resistant Esters

December 13, 2005 | Contact Author | By: John A. Imperante, Phoenix Chemical
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  • Keywords/Abstract

Keywords: esters | hydrolytic instability of esters | non-hydrolyzable esters | Saponification Value | testing

Abstract: Hydrolytic instability of esters in cosmetic products can be reduced, compared to that of standard straight chain esters, by using non-hydrolyzable esters synthesized from a diol reaction sequence. Two commercial dimer diol di-esters, given as examples, enable stable formulations at extremes of pH.

Hydrolytic instability of esters causes problems when esters are used in cosmetic formulations. One way around these problems is to use certain non-hydrolyzable esters that are synthesized by a diol reaction sequence. This sequence, two examples of the resulting non-hydrolyzable esters and some formulations using them are presented in this article.

Esters are a class of compounds well known to the organic chemist and to the cosmetic chemist. There are a number of sub-classes of esters that differ both in functionality and structure.  These include simple fatty-fatty esters, complex esters, polyesters, Guerbet esters, and water-soluble esters. Each type provides specific functionality in cosmetic formulations. For example, fatty-fatty esters are generally oil soluble and useful in the oil phase of creams and lotions. Complex esters – such as trioctyldodecyl citrate, Guerbet esters and polymeric esters – serve as pigment wetting and dispersing agents and in makeup and lipstick for substantivity, transfer resistance and moisturization.