Ring-opening polymerization of ethylene carbonate using ionic liquids as catalysts

Abstract

The ring-opening polymerization of ethylene carbonate was examined using ionic liquids, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4) and 1-butyl-3-methylimidazolium chlorozincate ([bmim]Cl-(ZnCl2)x), as polymerization catalysts. It was shown that the polymerization was accompanied with decarboxylation and chain cleavage reaction. As the reaction time increased, the monomer conversion increased and the content of ethylene carbonate units in the resultant polymer decreased, while the polymer molecular weight increased at first, reached a maximum and then decreased. It was also found that not only the polymerizing activity of the [bmim]Cl-(ZnCl2)x but also its performance for suppressing the decarboxylation and chain cleavage increased with the molar fraction of ZnCl2. It was deduced that the catalytic performance of ionic liquids mainly depended on their inorganic anions and that the larger the amount of these anions in the reaction system, the better the catalytic performance. The polymerizing activity of ionic liquids was much higher than conventional catalysts often used for the polymerization of ethylene carbonate.

Photo-Cross-Linked Poly(ethylene carbonate) Elastomers: Synthesis, in Vivo Degradation, and Determination of in Vivo Degradation Mechanism

“…To produce a series of PEC elastomers with different cross-link densities, a range of low-molecular-weight PEC diols was prepared. This was accomplished via depolymerization of 28 kg/mol ( M n ) linear PEC according to the method outlined by Sant’Angelo et al Depolymerization was necessary because the current processes for making PEC (copolymerization of CO 2 and EG) cannot produce polymers with molecular weights lower than 50 kg/mol without the polymers possessing extensive ethylene oxide units. , The number average molecular weight range of interest was 2000–10 000 g/mol. The thermal tin-catalyzed depolymerization unzipping reaction proceeds from the hydroxyl chain ends and produces ethylene carbonate monomer and shorter chain PEC diol.…”

Effect of ionic liquids on kinetic parameters of dicyanate ester polycyclotrimerization and on thermal and viscoelastic properties of resulting cyanate ester resins

“…Since they are nonflammable, non-volatile and recyclable, they are greener alternatives to conventional organic solvents. Furthermore, they may be used as effective and reusable catalysts in some polymerization reactions [9][10][11][12][13] and as initiators of free-radical [14,15] or cationic [16,17] polymerization processes. Thus, ILs have attracted widespread interest in polymer chemistry, due to their versatile properties [18,19].…”

Halometallate ionic liquids: thermal properties, decomposition pathways, and life cycle considerations

“…, 150–250 °C). 16–20 We also report solid–liquid transitions, which are important because they present a lower temperature limit, and together with thermal stability, define an operating range for the liquid medium. We report other industrially-relevant thermal parameters, such as long term thermal stabilities and heat capacities ( C o p ), which are used to estimate energy requirements for heating.…”

“…We present a particular focus on high temperature stability because many new applications utilise elevated temperatures for catalytic processes or material applications (e.g., 150-250 °C). [16][17][18][19][20] We also report solid-liquid transitions, which are important because they present a lower temperature limit, and together with thermal stability, define an operating range for the liquid medium. We report other industrially-relevant thermal parameters, such as long term thermal stabilities and heat capacities (C o p ), which are used to estimate energy requirements for heating.…”