Synthesis of biobased multivalent cross-linkers from a castor oil-derived C22-acyloin

A number of interesting biobased chemical building blocks were developed via the condensation of the C22 acyloin obtained from 10-undecenoic acid (castor oil and a non-edible oil) with mono- and bifunctional acid chlorides. Two terminally unsaturated acid chlorides (C3 and C11), three long chain saturated aliphatic acid chlorides (C10, C12 and C14), as well as the bifunctional adipoyl chloride were used. The condensation products were obtained as pure oils with potential cross-linking features and are therefore of interest as biobased crosslinkers for the polymer industry. The acyloin was successfully copolymerized in a radical emulsion copolymerization process, replacing diallyl phthalate. Radical, ionic or coordination homopolymerization of the same acyloin, however, did not work. Neither did the radical homopolymerization of undecenoyl acyloin. The acrylated acyloin, however, was transformed into a transparent glass upon solvent-free radical polymerization initiated by benzoyl peroxide. Thermogravimetric, Differential Scanning Calorimetry and Dynamic Mechanical Analyses were performed on the obtained polymer. Epoxidation of the triple unsaturated undecenoyl acyloin and the acyloin itself was evaluated as well.

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► A radically polymerizable monomer with thermoset characteristics was obtained from the C22 acyloin castor oil.
► The C22 acyloin was shown to be a valuable replacer for diallyl phthalate in a radical emulsion copolymerization process.
► Epoxidation of a triple unsaturated acyloin ester was successful, providing a precursor for biobased epoxy resins.
► Diisopropylethylamine was found a better base than trietylamine for the acrylation of 10-undecenoin.