Cationic ring-opening polymerization behavior of an aliphatic seven-membered cyclic carbonate, 1,3-dioxepan-2-one

Abstract

SUMMARY Synthesis and cationic ring-opening polymerization of a seven-membered cyclic carbonate, 1,3-dioxepan-2-0ne (l), were examined. The cationic ring-opening polymerization of 1 proceeded without decarboxylation at 20 "C to give the corresponding polycarbonate, differently from a six-membered cyclic carbonate (2), for which polymerization is generally accompanied by partial elimination of carbon dioxide. The observed polymerization rate of 1 in nitrobenzene was about 1.3 times faster than that in dichloromethane. The observed pseudo first-order polymerization rate constants of 1 and 2 at 20°C were determined to be 4.15 x lo4 and 4.16 x lod s-', respectively. The observed polymerization rate of 1 was 100 times larger than that of 2. The activation energies in the polymerization of 1 and 2 were estimated to be 6.27 and 8.52 kcal/mol, respectively.

Activated monomer cationic polymerization of 1,3-dioxepan-2-one initiated by water-hydrogen chloride

“…Incorporation of a chlorine group would be negligible by the absence of a signal around 3.6 ppm, assignable to a -methylene protons of a terminal chlorine group. No signal was observed at 3.40 -3.46 ppm based on methylene protons adjacent to an ether oxygen atom, which would be formed by decarboxylation 5) . This confirms that the ringopening polymerization of 7CC by the H 2 O1HCl initiator proceeded without decarboxylation, a typical side reaction in the cationic ring-opening polymerization of cyclic carbonates.…”

High‐Molecular‐Weight Polycarbonates Synthesized by Enzymatic ROP of a Cyclic Carbonate as a Green Process

“…The crude polymer was purified by reprecipitation using chloroform (good solvent)/methanol (poor solvent) to obtain PTeMC in 78% yield. The molecular structure was analyzed by 1 H NMR spectroscopy and no ether formation by decarboxylation during polymerization was detected, i.e., no peak due to methylene protons adjacent to an ether linkage appeared at δ = 3.2–3.6 12. No ether formation was detected in MALDI‐TOF MS of the lower molecular weight fractions.…”

“…The aliphatic polycarbonate, PTeMC, has so far been prepared by the conventional polycondensation of butane‐1,4‐diol and triphosgene in chloroform. However, both the molecular weight ($\overline M _{\rm n}$ = 2 000 g · mol −1 ) and yield (43%) were relatively low 12. We have previously reported that PTeMC was prepared by the lipase‐catalyzed polycondensation of butane‐1,4‐diol and diethyl carbonate using lipase from Candida antarctica (lipase CA) 13.…”

“…A cyclic tetramethylene carbonate (TeMC) monomer and a cyclic hexamethylene carbonate (HMC) dimer have been prepared by the condensation of butane‐1,4‐diol and poisonous triphosgene in a toluene solution using antipyrine, and the condensation of hexane‐1,6‐diol and diethyl carbonate using K 2 CO 3 . However, the yields (30%12 and 11%18) were relatively low, clearly indicating the need for a more environmentally benign production process. There has also been a report on the synthesis of cyclic TeMC monomer and dimer by the condensation of butane‐1,4‐diol and diethyl carbonate using K 2 CO 3 , but the yields of cyclic monomer and dimer were only 4 and 13%, respectively 19.…”

A novel acid promoted ring-opening polymerization of a seven-membered cyclic carbonate initiated with BCl3

“…in diethyl ether were purchased from Aldrich and used without further purification. 7CC was prepared according to the literature 7) . Dichloromethane was washed with water, pre-dried with MgSO 4 , and sequentially distilled from P 2 O 5 and CaH 2 .…”