Polymerization of L-Aspartic Acid to Polysuccinimide and Copoly(Succinimide-Aspartate) in Supercritical Carbon Dioxide
9259 Letters in Organic Chemistry, 2005, 2, 687-689 687 Polymerization of L-Aspartic Acid to Polysuccinimide and Copoly(Succinimide-Aspartate) in Supercritical Carbon Dioxide Kenneth M. Doll, 1 , Randal L. Shogren t2, Ronald A. Holser 1 , J.L. Willett2 and Graham Swift3 1 Food and Industrial Oil and 2Plant Polymer Research Units, National Center for Agricultural Utilization Research, United States Department of Agriculture, Agricultural Research Service, 1815 N. University St., Peoria, IL 61604, USA, 3Folia. Inc., 2800 Milan Court, Birmingham AL 35211 Received June 21, 2005: Revised August 21, 2005: Accepted September 05, 2005 Abstract: We have prepared two polymeric materials from L-aspartic acid in supercritical carbon dioxide, polysuccinimide and copoly(succinimide-aspartate). The polysuccinimide was characterized by JR spectroscopy and GPC analysis. The copoly(succinimide-aspartate) product was also characterized by titrometric analysis. These natural materials may prove useful in reducing our dependence on petroleum products. Keywords: Polysuccinimide, copoly(succinimide-aspartate), polyaspartic acid, supercritical carbon dioxide, natural polymer, amino acid polymer. The synthesis of polysuccinimide from L-aspartic acid, with or without acid catalysis (7-11]. It can also be Scheme (1) has a long history [1,2] L-aspartic acid or salts polymerized enzymatically [12]. The physical properties of of L-aspartate can be polymerized thermochemically [3-6], polysuccinimide have been studied, and found to be 0 0 OH )I NH No— OH HO (n+2) acid c at \\ 10 H2Nol L.,..,r:o 0 L OH Scheme 1. The synthesis of polysuccinimide from aspartic acid. 0 NH, )ç2 C N 4O +d Na 0 OrNa OH 0 -H2O -NH, H2N OH OH OH .iL o" idr Scheme 2.
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