Radial distribution functions (RDFs) of imidazolium-based ionic liquids were evaluated by adopting effective fragment potential version 2 -molecular dynamics simulation (EFP2-MD), whose force fields were defined by a set of simple ab initio quantum chemical calculations for each ionic fragment. It was found that EFP2-MD could reproduce RDFs of ion pairs much faster than ab initio MD without losing chemical accuracy. This means that EFP2-MD has a potential to predict and design thermodynamic properties of novel ionic liquids. Keywords: Ionic liquid | EFP2-MD | Ab initio force fieldIonic liquids are highly stable, heat-resistant, and non-volatile solvents that are important in industrial fields.1 The unique properties are determined by the intermolecular interaction among ionic species in the ionic liquids. Conventionally, classical MD has been used to understand the solution structure of ionic liquids. However, even some classical force fields have been reported for specific ionic liquids with great efforts, 3 we cannot apply them for designing novel ionic liquids in a direct manner. In the backgrounds, ab initio MD, which does not need any pre-optimized force field parameters, has gradually caught attention with the growth of high-performance computers. 4 However, as ab initio MD is based on quantum mechanics, its computational cost is extremely higher than the classical one. Thus, a method having both high chemical accuracy and low computational cost is strongly required. The object of this study is to propose such a method based on EFP2 theory reported by Day et al. 5 However, EFP2 theory has been applied mainly for neutral molecular systems. 6 The performance of EFP2 theory has not been entirely clear for ionic systems. In this paper, we discuss the possibility of EFP2 theory for describing thermodynamic properties of ionic liquids.Before presenting main results, here we briefly remind EFP2 theory that occupies an essential part of this study.5 EFP2 is an intermolecular force field that is systematically defined by ab initio wave function theory. To define EFP2, rigid rotor approximation is generally applied. In other words, in EFP2 theory, internal degrees of freedom in target molecules are fixed and only relative molecular motions are focused on. Intermolecular interaction energy is evaluated as a sum of five physicochemical components, i.e., electrostatic (ES), exchange repulsion (EX), polarization (POL), dispersion (DISP), and charge transfer (CT) terms, where all terms can be expressed by a set of quantum mechanical formulae. The details of EFP2 theory have been reported elsewhere. In this study, a set of quantum chemical calculations was performed to evaluate intermolecular interactions in our target systems. All the quantum chemical calculations were performed using GAMESS 8 and Gaussian09 9 programs. Generally, ionic liquids are composed of large organic ions to weaken the attractive forces among ionic species and to reduce their melting points. Thus, it is important to know their interacting posi...

Efficient CO2 capture is indispensable for achieving a carbon-neutral society while maintaining a high quality of life. Since the discovery that ionic liquids (ILs) can absorb CO2, various solvents composed of molecular ions have been developed and their CO2 solubility has been studied. However, it is challenging to optimize these materials to realize targeted properties as the number of candidate ion combinations for designing novel ILs is of the order of 1018. In this study, electronic- structure informatics was applied as an interdisciplinary approach to quantum chemistry calculations, and combined with machine learning to search 402,114 IL candidates to identify those with better CO2 solubility than known materials. Guided by the machine-learning results, trihexyl(tetradecyl)phosphonium perfluorooctanesulfonate was synthesized and it was experimentally confirmed that this IL has higher CO2 solubility than trihexyl(tetradecyl)phosphonium bis(trifluoromethanesulfonyl)amide, which is the previous best IL for CO2 absorption. The method developed in this study could be transferable to gas-absorbing liquids in general, such as deep eutectic solvents (hydrogen-bonded mixed organic solvents in a broad sense), which also have numerous practical applications. Therefore, we believe that our method for developing functional liquids will significantly contribute to the development of a carbon-neutral society.

Ionic liquids (ILs) are non-volatile and highly stable solvents, which consist of organic/inorganic cations and anions. ILs are attractive since they can be utilized as gas-separating materials. Using a conductor-like screening model for realistic solvation (COSMO-RS) method, in this study, Henry's law constants of 15 gases (HCN,

The COVID-19 pandemic has led to an increasing amount of research on redesigning educational models. This paper describes the contents of a new laboratory course on physical chemistry based on blended learning, designed for third-year students in the Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University. We provided students with digest video materials for flipped learning, a cloud computing environment, and video conferencing tools. These materials enhanced the course contents to facilitate effective education during the pandemic. The results of a questionnaire survey showed that students were delighted with the new course, which comprehensively included experiments, computation, and data science.