Microscopic Origins for the Favorable Solvation of Carbonate Ether Copolymers in CO₂

Abstract

The strong desire for the wide use of carbon dioxide as an environmentally benign process solvent has spurred a large number of attempts to improve its solubility characteristics. Pioneering experimental work by Beckman and co-workers has pointed to carbonate ether copolymers as promising candidates for nonfluorous surfactants. It is demonstrated here that Gibbs ensemble Monte Carlo simulations (using configurational-bias and double-bridging strategies and the transferable potentials for phase equilibria force field) can be employed to accurately predict the phase equilibria of a carbonate ether copolymer with CO2. The simulations indicate that the greater accessibility of the carbonyl oxygen plays a major role for the CO2-philicity of this copolymer surfactant.

A theoretical study of structure–solubility correlations of carbon dioxide in polymers containing ether and carbonyl groups

“…The results are also shown in Fig. 15. One can see that the solubility values are nearly the same above 330 K. Below 330 K, the solubilites with and without the partial charges are different, and the gap increases as the temperature decreases.…”

“…At relatively low pressure, the second term on the left-hand side of eqn ( 12) is nearly zero and can be neglected. Meanwhile, at low solubility, the interactions between CO 2 -CO 2 in the polymer can also be neglected in eqn (14) and (15). To solve eqn (12) with the PRISM theory, an iterative process is necessary.…”

“…13,14 The PPC-PEO copolymer displayed an enhanced solubility characteristics compared with that of the PEO homopolymer. 15 Polyethers work as solubilityselective membrane materials on account of the specific binding of this acid gas with the ether groups in the polymeric chain. The high solubility of CO 2 in polyesters is attributed to the favorable specific interactions between CO 2 and the acetate groups.…”

Molecular exchange Monte Carlo: A generalized method for identity exchanges in grand canonical Monte Carlo simulations

“…To address this issue, Kindt introduced the idea of "solvent repacking" for two-dimensional hard-disk and size asymmetric three-dimensional Lennard-Jones systems, where configurational-bias was used to determine the positions of solvent particles in the large-small particle identity exchange [29,32]. While a number of publications state that an identity exchange move was used for molecular systems [33][34][35], a detailed description of the algorithm and the acceptance criteria have not been published to date.…”

Incorporating a silicon unit into a polyether backbone—an effective approach to enhance polyether solubility in CO2

“…Beckman and co-workers 31 masterly designed ethercarbonate copolymers through incorporating CO 2 -philic carbonyl group 32 into a polyether backbone by aluminumcatalyzed copolymerization of cyclic ethers with CO 2 ; the resulting statistical copolymers exhibited extremely high solubility in CO 2 . Subsequently, Cooper et al 33 developed a step growth polymerization route to synthesize the ether-carbonate copolymers and Wick 34 further certied the major role of ether-carbonate copolymers-CO 2 interactions on the increased solubility of the polymer in CO 2 through Gibbs ensemble Monte Carlo simulations. In addition, the introduction of uorine into the polyether backbone remarkably enhanced the solubility of polyether in CO 2 .…”