Copolymerization of carbon dioxide and some oxiranes by organoaluminium catalysts

Abstract

Carbon dioxide was copolymerized with methyloxirane and 7‐oxabicyclo[4.1.0]heptane using triethylaluminium as a catalyst component. Factors to control the copolymer composition were sought on the basis of an assumed copolymerization mechanism. Compared to nonpolar solvents, ethereal solvents were found to increase the carbon dioxide content in the copolymer obtained by the triethylaluminium/water system, giving a fraction with almost alternating sequence. The addition of a Lewis base, especially treiphenylphosphine, to triethylaluminium was also useful to get copolymers of high carbon dioxide content. The coincidence of these results with the expectation from the assumed copolymerization scheme clearly indicates that the copolymerization proceeds through a coordinated anionic mechanism.

Highly Enantioselective Catalytic System for Asymmetric Copolymerization of Carbon Dioxide and Cyclohexene Oxide

“…In addition, the 1 H NMR spectrum of the copolymer in Figure 3 (b) shows that the chemoselectivity was also outstanding. The completely alternating structure (>99 % carbonate linkage) of the PCHC was confirmed by the absolute predominance of a methine proton peak at δ =4.62 ppm (assigned to carbonates), and the absence of a methine proton peak around δ =3.45 ppm (attributed to a polyether from homopolymerization of the CHO) 21. Differential scanning calorimetry analysis of the copolymer showed that a high crystallization endothermic peak was observed at 240 °C, implying that the PCHC with over 90 % enantioselectivity exhibited crystallization 8…”

“…The completely alternating structure (> 99 % carbonate linkage) of the PCHC was confirmed by the absolute predominance of a methine proton peak at d = 4.62 ppm (assigned to carbonates), and the absence of a methine proton peak around d = 3.45 ppm (attributed to a polyether from homopolymerization of the CHO). [21] Differential scanning calorimetry analysis of the copolymer showed that a high crystallization endothermic peak was observed at 240 8C, implying that the PCHC with over 90 % enantioselectivity exhibited crystallization. [8] In conclusion, a novel ligand with the azetidine ring shows excellent enantioselectivity for the catalytic asymmetric copoly-merization of CO 2 and CHO catalyzed by dinuclear zinc(II).…”

Copolymerization of carbon dioxide and epoxide

“…Early investigations used the triethylaluminum-water system 37 for comparison with the diethylzinc-water system. For example, when the copolymerization of carbon dioxide and propylene oxide was carried out under 50 atm carbon dioxide in various solvents, the triethylaluminum-water (1:1) system produced a copolymer with a carbon dioxide content of only about 10%.…”

Polymerization of methyl methacrylate and other polar monomers with alkylaluminum initiators bearing bidentate and tridentate N‐ and O‐donor ligands

“…Jérôme, Penczek, and others1–4 have used simple aluminum alkoxides and thiolates for the synthesis of a wide variety of polylactone and polylactide homopolymers and block copolymers. Similar aluminum alkoxides act as catalysts for carbonate and oxirane homopolymerizations and copolymerizations 5–10. Cationic and neutral ligated aluminum complexes have also been used as polymerization catalysts: Atwood11 has used aluminum cations stabilized by tetradentate N,N ′ ,O,O ′‐ligated SALEN ( N,N ′‐ethylenebis[salicylideneimine]) ligands for the cationic oligomerization of oxiranes; other groups12–17 have studied neutral aluminum SALEN complexes for oxirane, acrylate, and lactide polymerization.…”