Method of making mixed pentaerythritol esters having up to 75 percent thio-containing side chains

摘要

Pentaerythritol co-esters derived from pentaerythritol, (3-alkyl-4-hydroxyphenyl)-alkanoic acids and alkylthioalkanoic acids or lower alkyl esters of such acids are useful as stabilizers of organic material normally susceptible to oxidative and/or thermal deterioration. The co-esters are advantageously prepared by transesterification of such esters with pentaerythritol. Preferred co-esters are (I) pentaerythritol tris[3,5-di-tert-butyl-4-hydroxyphenyl)propionate]-mono[3-n-dodecylthi opropionate] and (II) pentaerythritol bis[-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]-bis[3-n-dodecylthi opropionate]. The co-esters are especially useful in stabilizing applications for which physical mixtures of (i) (3-alkyl-4-hydroxyphenylalkanoic acid esters of polyols with (ii) polyalkanol esters of alkylthioalkanoic acids have heretofore been proposed.