Computer-Aided Screening of Ionic Liquids As Entrainers for Separating Methyl Acetate and Methanol via Extractive Distillation

In the production of poly­(vinyl alcohol), the raw materials methyl acetate (MeOAc) and methanol (MeOH) exist as a homogeneous azeotropic mixture. Twenty-five kinds of ionic liquids, composed of five types of cations and five types of anions, were studied using the COSMO-SAC method. The σ-profile data for each component and the selectivity at infinite dilution (<i>S</i>^∞) were calculated and analyzed, respectively. 1-Hexyl-3-methylimidazolium chloride ([HMIM]­[Cl]) and 1-butyl-3-methylimidazolium chloride ([BMIM]­[Cl]) were selected as suitable entrainers based on the COSMO-SAC method. The binary interaction parameters of the NRTL model of the MeOAc/ionic liquid and MeOH/ionic liquid systems were regressed. The conceptual design for the separation of MeOAc and MeOH using ionic liquids as entrainers was investigated. The comparison of two processes using two entrainers was carried out from an economic perspective. The total annual cost (TAC) of the process using [HMIM]­[Cl] as an entrainer can be reduced by 16.5% compared with that of the process using [BMIM]­[Cl]. The results indicated that the COSMO-SAC method is feasible for screening ionic liquids as optimal entrainers. This work could provide theoretical instruction for further industrial applications using ionic liquids as solvents via COSMO-SAC computer-aided screening

Liquid–Liquid Extraction of Butanol from Heptane + Butanol Mixture by Ionic Liquids

Selection of a suitable solvent is the key for the extraction process. In this work, four ionic liquids were selected as solvent for extracting butanol, the ternary liquid–liquid equilibria (LLE) data for systems of heptane + butanol + {[HMIM]­[BF₄] (1-hexyl-3-methylimidazolium tetrafluoroborate), [OMIM]­[BF₄] (1-octyl-3-methylimidazolium tetrafluoroborate), [HMIM]­[OTf] (1-hexyl-3-methylimidazolium trifluoromethansulfonate), and [HMIM]­[NTf₂] (1-hexyl-3-methylimidazolium bis­((trifluoromethyl)­sulfonyl)­imide)} were measured at 298.15 K and atmospheric pressure. The extraction capacity of four ILs in the separation of butanol from heptane + butanol mixture was estimated by the selectivity (<i>S</i>) and solute distribution ratio (β), and the influence of the structure and anion of IL on the extraction efficiency was investigated. The experimental LLE data were correlated by using NRTL and UNIQUAC models

Controllability of the Conductive Filament in Porous SiO_<i>x</i> Memristors by Humidity-Mediated Silver Ion Migration

Oxide-based memristors composed of Ag/porous SiOx/Si stacks are fabricated using different etching time durations between 0 and 90 s, and the memristive properties are analyzed in the relative humidity (RH) range of 30–60%. The combination of humidity and porous structure provides binding sites to control silver filament formation with a confined nanoscale channel. The memristive properties of devices show high on/off ratios up to 108 and a dispersion coefficient of 0.1% of the high resistance state (CHRS) when the RH increases to 60%. Humidity-mediated silver ion migration in the porous SiOx memristors is investigated, and the mechanism leading to the synergistic effects between the porous structure and environmental humidity is elucidated. The artificial neural network constructed theoretically shows that the recognition rate increases from 60.9 to 85.29% in the RH range of 30–60%. The results and theoretical understanding provide insights into the design and optimization of oxide-based memristors in neuromorphic computing applications