Adsorption behavior of α-tocopheryl succinate and α-tocopheryl polyethylene glycol succinate onto weakly basic anion exchange resins

Abstract

Polyethylene glycol (PEG) esters are important, nontoxic and biodegradable non-ionic surfactants. A key procedure in producing PEG esters is their separation from unreacted or excess acids. We propose an adsorption method using the weakly basic anion exchange resins for the separation of organic acids and PEG esters for the first time. With α-tocopheryl polyethylene glycol succinate (TPGS) and α-tocopheryl succinate (α-TS) as the examples of PEG ester and organic acid, respectively, single-component equilibrium experiments revealed the great potential of this method. Studies on the adsorption equilibrium, thermodynamics and kinetics of α-TS onto a weakly basic anion exchange resin were also carried out. This research is not only important for the production of TPGS, but also instructive for the separation of other PEG-esters from the reaction mixtures.