Polymerization ability of cis‐ and trans‐4,5‐epoxy‐2‐pentenal with ionic and free radical initiators. Cyclopolymerization of the cis isomer

Abstract

SynopsisThe behavior of the readily available cis-(1) and trans-(2) 4,5-epoxy-2-penten& toward classical cationic, anionic, and free radical initiators has been examined. Only the cationic polymerization of 1 gave soluble polymer of moderate molecular weights. This polymer possessed predominantly the cyclopolymerized furanose structure 12. Cationic initiation of 2 and anionic initiation of both 1 and 2 gave only crosslinked materials, and free radical initiators with 1 and 2 gave no polymer. EXPERIMENTALInstrumentation lH-NMR spectra were obtained using a Varian-T6O and a Bruker WM-250Multinuclear FT spectrometer. Infrared spectra were recorded using a Perkin-Elmer 710A spectrophotometer. Elemental analyses were performed by the University of Arizona Analytical Center (Tucson, Arizona). The numberaverage molecular weight of the polymers was determined in dichloromethane at 37OC using a Hewlett-Packard vapor pressure osmometer model 302B. Monomers cis-(I) and trans-4,5-Epoxy-Z-Pentenal.(2)'Commercial (Tridom-Fluka) cisand tram-4,5-epoxy-2-pentenal(90% pure) were purified by using a spinning band distillation column (1 m) of the Perkin-Elmer Manufacturing Corp. The purity of monomer was checked by lH-NMR spectroscopy (>98% for 1 and >99% for 2). bp 59-60°C/6 mm Hg for 1 and 52OC/5 mm Hg for 2; IR (CCk) for 1: 3050 (VC-H, CH2 of epoxy ring, m), 3020 (VC-H, CH of epoxy ring and CH=CH, w), 2780 (w), 2755 (m), and 2735 (m)

Synthesis and ring-opening polymerization of novel bicyclic oxalactams. 2-Oxa-6-azabicyclo[2.2.2]octan-5-one

“…As shown in Scheme III, there are three possible ringopening modes of 2,6-BOL in its cationic polymerization: (1) The C(5)-N(6) bond cleavage (a) would lead to polyamide composed of cis-2,5-linked tetrahydropyran rings. (2) The C(l)-N(6) bond cleavage (b) would give rise to polyamide consisting of trans-2,6-linked tetrahydropyran rings (Sn2) or a mixture of transand cis-2,6linked tetrahydropyran rings (SN1). (3) The C(l)-0(2) bond cleavage (c) would yield polyether composed of trans-3.6-linked 2-piperidinone rings (SN2) or a mixture of cisand trans-3,6-linked 2-piperidinone rings (SN1).…”