3 research outputs found
Computer-Aided Screening of Ionic Liquids As Entrainers for Separating Methyl Acetate and Methanol via Extractive Distillation
In the production of polyÂ(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><sup>∞</sup>) were
calculated and analyzed, respectively. 1-Hexyl-3-methylimidazolium
chloride ([HMIM]Â[Cl]) and 1-butyl-3-methylimidazolium chloride ([BMIM]Â[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]Â[Cl] as an entrainer
can be reduced by 16.5% compared with that of the process using [BMIM]Â[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]Â[BF<sub>4</sub>] (1-hexyl-3-methylimidazolium
tetrafluoroborate), [OMIM]Â[BF<sub>4</sub>] (1-octyl-3-methylimidazolium
tetrafluoroborate), [HMIM]Â[OTf] (1-hexyl-3-methylimidazolium trifluoromethansulfonate),
and [HMIM]Â[NTf<sub>2</sub>] (1-hexyl-3-methylimidazolium bisÂ((trifluoromethyl)Âsulfonyl)Âimide)}
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<sub><i>x</i></sub> 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