Anionic ring-opening polymerization behavior of a seven-membered cyclic carbonate; 1, 3-dioxepan-2-one

Abstract

Anionic ring‐opening polymerization of a seven‐membered cyclic carbonate, 1,3‐dioxepan‐2‐one (1), was carried out to observe that the higher the polymerization temperature and lower the initial monomer concentration were, the lower the yield and molecular weight, and wider the molecular weight distribution of the obtained polymers were. The back‐biting reaction and the formation of cyclic oligomers of 1 were observed during the polymerization of 1. The relative polymerization rate of 1 was about 35 times faster than that of six‐membered carbonate, 1,3‐dioxan‐2‐one (3). The ΔHps of 1 and 3 estimated by MO (PM3) calculations were −9.8 and −4.4 kcal/mol, respectively. 1 could easily undergo the ring‐opening polymerization based on larger ring strain. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1375–1380, 1997

Polyaddition of bis(seven‐membered cyclic carbonate) with diamines: A novel and efficient synthetic method for polyhydroxyurethanes

“…These results might be based on the ring strain of six‐membered cyclic carbonates being larger than that of five‐membered cyclic carbonates 8. If this assumption is correct, we may get polyhydroxyurethanes more efficiently by employing a bifunctional seven‐membered cyclic carbonate because a seven‐ membered cyclic carbonate undergoes anionic and cationic polymerization more rapidly than the corresponding six‐membered cyclic carbonate, probably because of the larger ring strain 9. In this article, we report the synthesis and polyaddition of a bis(seven‐membered cyclic carbonate) with diamines, along with the model reaction of a seven‐membered cyclic carbonate with amines.…”

The anionic ring-opening polymerization of five-membered cyclic carbonates fused to the cyclohexane ring

“…[1][2][3] For their synthesis, various procedures have been used, that is, (i) the polycondensation between the carbonate derivatives and diols, 4 (ii) the ring-opening polymerization of cyclic carbonates, [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] and (iii) the alternating polymerization of epoxides with carbon dioxide. Among these procedures, the ring-opening polymerizations of cyclic carbonates have the potential to control the molecular weight and to induce copolymerization with other cyclic monomers.…”

“…Six-membered cycles (or larger) using anionic initiators tend to polymerize smoothly, yielding the corresponding polycarbonate at a lower temperature (o100 1C). [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] In contrast, the anionic ring-opening polymerization of the fivemembered ring is thermodynamically unfavorable and proceeds at a higher temperature (4150 1C), causing the elimination of carbon dioxide to produce a copolymer that consists of both carbonate and ether linkages. [20][21][22][23][24][25] However, we reported that the anionic ringopening polymerization of a five-membered cyclic carbonate (MBCG) (Figure 1) possessing the a,D-glucopyranoside structure proceeded even at 0 1C to produce an aliphatic polycarbonate without the elimination of carbon dioxide.…”

Living ring-opening polymerization of cyclic carbonates mediated by bulky titanium bisphenolates

“…[5] In contrast, the polymerization of cyclic carbonates with 7-membered rings has not been fully investigated. [6,7] With respect to the living polymerization, few examples have been reported. sec-BuLi, which initiates the living anionic polymerization of 5,5-dimethyl-1,3-dioxan-2-one (DM6CC), [5 a] can also initiate the polymerization of 1,3-dioxepan-2-one (7CC), but a living character has not been observed.…”

“…The DP of the polymer(6) was close to the monomer-to-H 2 O mole ratio(5), indicating that each H 2 O molecule produces one polymer molecule.This mechanism is also consistent with the polymerization of 7CC initiated by 1 or 3, where the polymerization may be considered to be initiated by titanium alcoholate (monoinitiator) and the contaminant H 2 O (bisinitiator), affording poly(7CC) with a bimodal molecular weight distribution. These results motivated us to examine the polymerization of 7CC by bisalcoholate complexes of titanium bisphenolate in the presence of a dehydrator.…”