Synthesis of Modified Polycaprolactams Obtained from Renewable Resources

Modified caprolactam monomers, derived from renewable resources, are prepared to obtain novel polyamides with tunable properties. Starting from 2-cyclohex-1-enone, a thia-Michael addition is used as key step to synthesize modified monomer precursors. The monomer synthesis is optimized in order to achieve high yields utilizing environmentally benign synthesis procedures. The modified caprolactam monomers are obtained with high regioselectivity via the Beckmann rearrangement of the prepared cyclohexanone oximes. Using tin(II)2-ethylhexanoat (Sn(Oct)(2)) as catalyst, it is possible to obtain the modified polycaprolactams in good yields. It is noteworthy that for the synthesis of the regioselective caprolactam monomers, the use of toxic reagents is avoided and the generation of waste is minimized in order to meet the requirements for environmentally benign synthesis procedures.