Synthesis of new polyethers derived from isoidide under phase‐transfer catalysis: Reactivity and selectivity under microwaves and classical heating

Abstract

ABSTRACT:Microwave irradiation was applied to the synthesis of polyethers from 1,8-dibromo-and 1,8-dimesyloctane under solid-liquid phase-transfer catalytic conditions. To evaluate the influence of microwaves on the reaction rates and polyether properties, we carried out the polymerization reactions under similar conventional conditions (oil bath) with the same temperature profiles. First, the microwave-assisted syntheses proceeded more rapidly in comparison with conventional heating, and the reaction time was reduced from 24 h to 30 min with higher yields of polyethers. Second, the structure of the polymers strictly depended on the activation mode. Under microwave conditions, the polyethers were characterized by higher molecular weights with better homogeneity. Third, the mechanism of chain termination was different under microwave and conventional conditions. The polyethers prepared with conventional heating possessed shorter chains with mainly hydroxylated ends, whereas under microwave irradiation, the polymer chains were longer with mainly ethylenic group ends. In fact, under microwave irradiation, ethylenic group ends were formed rather rapidly and set up a hindrance to further polymer growth. In contrast, under conventional conditions terminations were essentially constituted by hydroxyl functions; however, further polymerization was terminated as well.

Chemistry, functionality, and coating performance of biobased copolycarbonates from 1,4:3,6‐dianhydrohexitols

“…The broad PDI as well as the limited solubility of polymer 5 in CHCl 3 suggest that branching and/or crosslinking has occurred, possibly through acid catalyzed ring‐opening of the anhydro ether ring of IM 34, 35. This ether ring is known to be less stable than its counterparts present in IS and II 36–38. Polycarbonates 1 and 3 have PDI values below 2 and are fully soluble in CHCl 3 as well as in HFIP.…”

Microwave‐Assisted Polymer Synthesis: State‐of‐the‐Art and Future Perspectives

“…[71] Loupy and co-workers observed shifts in selectivity (as a consequence of microwave irradiation) for the polyetherification of isosorbide (1,4:3,6-dianhydro-D-sorbitol) or isoidide (1,4:3,6-dianhydro-L-iditol) with 1,8-dibromo and 1,8-dimesyloctane (Scheme 7). [72,73] A solution of equimolar amounts of the corresponding educts in toluene was subjected to phase-transfer catalyzed polymerization in the presence of tetrabutylammonium bromide and aqueous potassium hydroxide under microwave irradiation (Synthewave 402, Prolabo) as well as conventional heating. For the isosorbide-containing polymers, it was found that the reaction rates increased under microwave irradiation, providing polymers in yields of around 70% within 30 min.…”

Preparation and mechanical properties of a copolycarbonate composed of bio-based isosorbide and bisphenol A

“…16,17 Isosorbide is thermally stable, available in large quantities and useful for the synthesis of bio-based polymers, such as polyesters, [18][19][20][21][22][23][24][25][26][27][28] polyamides 29 and polyurethanes. [30][31][32][33][34][35][36] A polycarbonate derived from petroleum is a bisphenol A-based polycarbonate (BPAPC). BPAPC possesses superior properties, such as high transparency, impact resistance, high tensile strength, durability and heat resistance.…”