Ring-opening of γ-valerolactone with amino compounds

Diols obtained by the ring-opening of biomass-based gamma-valerolactone (GVL) are potentially valuable building blocks that can be used as precursors in the manufacture of green polymers and resins. We report here a study on the ring-opening of GVL through adding amine compounds. The reactivity of the applied amine compounds in this ring-opening was tested by varying the structure of the amine compounds. Both mono-amines (ammonium, 2-aminoethanol, 2-phenylethylamine, and morpholine) and di-amines (1,2-diaminoethane, 1,2-diaminopropane, and piperazine) were used. The study showed that steric hindrance at the reacting amine-function plays a more prominent role than local point charge. To optimize the yield of the desired di-functional monomers, the ring-opening of GVL with 1,2-diaminoethane (1,2-DE) was studied in more detail. Reaction temperature (25-100 degrees C), reaction time, and molar ratio of the reactants appeared to be the determining processing parameters. These were found to be more important than the use of catalysts (triphenylphosphine, Tin(II)-2-ethylhexanoate, Ytterbium(III)trifuoromethanesulfonate, AlCl3, and SnCl2) and solvent polarity (methanol, DMA, DMSO, and water). (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 3556-3564, 2012