A sustainable tandem catalysis approach to plant oil based polyols via Schenck-Ene reaction and epoxidation

Abstract

Novel polyols were synthesized in a one-pot, tandem reaction approach. First, singlet oxygen was used as oxidant in the photochemical Schenck-Ene reaction to obtain allyl hydroperoxides of triglycerides, which were reacted in situ to the corresponding epoxy alcohols catalyzed by titanium(IV) isopropoxide. Subsequent acidic epoxide ring-opening with perchloric acid yielded a triglyceride-based polyol. Under basic conditions applying aqueous sodium hydroxide solution, cleavage of the ester bonds of the triglyceride and epoxide ring-opening occurred simultaneously resulting in a fatty acid-based polyol.

Practical applications: Polyols, especially also based on renewable fatty acids, are valuable monomers for the synthesis of polyurethanes, polyester- and alkyd-resins. With the here reported method, a maximum of three hydroxyl groups per double bond of the unsaturated triglyceride can be introduced, which cannot be realized with the methods reported to date.

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