Vapor-Liquid Equilibrium of Ionic Liquid 7-Methyl-1,5,7-triazabicyclo[4.4.0]dec-5-enium Acetate and Its Mixtures with Water

Ionic liquids have the potential to be used for extracting valuable chemicals from raw materials. These processes often involve water, and after extraction, the water or other chemicals must be removed from the ionic liquid, so it can be reused. To help in designing such processes, we present data on the vapor-liquid equilibrium of the system containing protic ionic liquid 7-methyl-1,5,7-triazabicyclo [ 4.4.0 ] dec-5-enium acetate, water, acetic acid, and 7-methyl-1,5,7-triazabicyclo [4.4.0] dec-5-ene. Earlier studies have only focused on mixtures of water and an ionic liquid with a stoichiometric ratio of the ions. Here, we also investigated mixtures containing an excess of the acid or base component because in real systems with protic ionic liquids, the amount of acid and base in the mixture can vary. We modeled the data using both the ePC-SAFT and NRTL models, and we compared the performance of different modeling strategies. We also experimentally determined the vapor composition for a few of the samples, but none of the modeling strategies tested could accurately predict the concentration of the acid and base components in the vapor phase.Peer reviewe

Modelling aerosol transport and virus exposure with numerical simulations in relation to SARS-CoV-2 transmission by inhalation indoors

We provide research findings on the physics of aerosol and droplet dispersion relevant to the hypothesized aerosol transmission of SARS-CoV-2 during the current pandemic. We utilize physics-based modeling at different levels of complexity, along with previous literature on coronaviruses, to investigate the possibility of airborne transmission. The previous literature, our 0D-3D simulations by various physics-based models, and theoretical calculations, indicate that the typical size range of speech and cough originated droplets (dPeer reviewe

Physical Properties of 7-Methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (mTBD)

7-Methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (mTBD) has useful catalytic properties and can form an ionic liquid when mixed with an acid. Despite its potential usefulness, no data on its thermodynamic and transport properties are currently available in the literature. Here we present the first reliable public data on the liquid vapor pressure (temperature from 318.23K to 451.2K and pressure from 11.1Pa to 10000Pa), liquid compressed density (293.15K to 473.15K and 0.092MPa to 15.788MPa), liquid isobaric heat capacity (312.48K to 391.50K), melting properties, liquid thermal conductivity (299.0K to 372.9K), liquid refractive index (293.15K to 343.15K), liquid viscosity (290.79K to 363.00K), liquid-vapor enthalpy of vaporization (318.23K to 451.2K), liquid thermal expansion coefficient (293.15K to 473.15K), and liquid isothermal compressibility of mTBD (293.15K to 473.15). The properties of mTBD were compared with those of other relevant compounds, including 1,5-diazabicyclo(4.3.0)non-5-ene (DBN), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), and 1,1,3,3-tetramethylguanidine (TMG). We used the PC-SAFT equation of state to model the thermodynamic properties of mTBD, DBN, DBU, and TMG. The PC-SAFT parameters were optimized using experimental data.Peer reviewe

Calculation of multicomponent mass transfer between dispersed and continuous phases

In many industrially important unit operations, mass transfer between dispersed and continuous phases takes place. The accurate and fast solution of the mass transfer model equations is essential in order to design these unit operations accurately. The mass transfer rate between phases is calculated in two parts. The first part is to solve the interphasial mass transfer fluxes. With multicomponent systems, this is best done with the Maxwell-Stefan diffusion model along with a mass transfer model. The other part is to calculate the mass transfer area between the phases. This can be done with population balance models, preferably with a flow model that discriminates various regions of the modeled system. The flow model is needed if the phenomena affecting the development of the mass transfer area are not homogeneous in separate parts of the considered region. The mass transfer rate needed in the material balances is then a product of the mass transfer fluxes and the mass transfer area. The mass transfer calculations with the Maxwell-Stefan model leads to complicated matrix function calculations. This is very time consuming because these models need to be solved many times during the solution of a unit operation or reactor model. Two simplifications to these complicated functions are presented in this work. The first is a method to calculate general matrix functions related to the multicomponent mass transfer models approximately. It is based on the fact that the diffusion coefficient matrices have larger diagonal than off-diagonal elements. The other approximation is a linearization of the high flux correction. The applicability of these two approximations, along with other modeling aspects, is considered with a distillation tray model. An approximation was also presented in this work for calculating diffusion, and further the mass transfer coefficients, within spherical particles. A population balance approach is used with a stirred tank flow model to calculate drop size distributions in liquid-liquid dispersions. In order to test the applicability of the flow model with population balances, drop size distributions are measured and the drop breakage and coalescence function parameter values are estimated. The inhomogeneous character of the dispersion in a stirred tank can be used in the parameter estimation process.reviewe

Approximating catalyst effectiveness factors with reaction rate profiles

A novel approximate solution for catalyst effectiveness factors is presented. It is based on carefully selected approximate reaction rate profiles, instead of typical assumption of composition profiles inside the catalyst. This formulation allows analytical solution of the approximate model, leading to a very simple iterative solution for effectiveness factor for general nonlinear reaction stoichiometry and arbitrary catalyst particle shape. The same model can be used with all practical Thiele modulus values, including multicomponent systems with inert compounds. Furthermore, the correct formulation of the underlying physical model equation is discussed. It is shown that an incorrect but often-used model formulation where convective mass transfer has been neglected may lead to much higher errors than the present approximation. Even with a correctly formulated physical model, rigorous discretization of the catalyst particle volume may have unexpectedly high numerical errors, even exceeding those with the present approximate solution. The proposed approximate solution was tested with a number of examples. The first was an equimolar reaction with first order kinetics, for which analytical solutions are available for the standard catalyst particle geometries (slab, long cylinder, and sphere). Then, the method was tested with a second order reaction in three cases: (1) with one pure reactant, (2) with inert present, and (3) with two reactants and non-stoichiometric surface concentrations. Finally, the method was tested with an industrially relevant catalytic toluene hydrogenation including Maxwell-Stefan formulation for the diffusion fluxes. In all the tested systems, the results were practically identical when compared to the analytical solutions or rigorous finite volume solution of the same problem.Peer reviewe

Modeling surfactant and drop size dynamics in polydisperse liquid-liquid systems with population balances

Funding Information: None. Publisher Copyright: © 2021 The AuthorA population balance framework based on high order moment conserving method of classes is extended to capture surfactant dynamics and its effect on drop size distributions. The proposed method is flexible for incorporating various closure models for drop breakage and coalescence, mass transfer, and physical equilibria between dispersed and continuous phase as well as for adsorption to the interface. The method is first schematically explained and derived in a generic form, and then appropriate closure models are discussed. The model is accurate and fast and can be implemented in process models, parameter optimization algorithms, and computational fluid dynamics software due to its high accuracy with limited number of additional variables.Peer reviewe

Modelling the fragmentation kinetics of the heterogeneous lignin macromolecule during kraft pulping with stochastic graphs

Funding Information: This work was financially supported and part of the Academy of Finland’s Flagship Program under Projects No. 318890 and 318891 (Competence Center for Materials Bioeconomy, FinnCERES). Publisher Copyright: © 2023 The Author(s)This article presents a novel concept for modelling the kinetics and related phenomena of the kraft pulping process on a macromolecule level with the initial objective to explicitly model and relate the breakage of phenolic and non-phenolic β—O—4 bonds to the observed three-stage delignification profile. The modelling frameworks consist of the building and the fragmentation of the lignin macromolecules. The macromolecules are modelled as stochastic graphs where monolignol object nodes are reassembled in a Monte Carlo approach into internal structures, which aggregate to a lignin macromolecule interconnected through chemical bonds represented by the edges of the graphs. The fractionation follows the splitting of β—O—4 ether bonds with different configurations resulting from functional groups attached to the monolignols, namely the phenolic and non-phenolic β—O—4 bonds with their respective stereochemistry. It is tested against a previously published model based on an extension of the established Purdue kineticmodel and experimental data. The results align with the observed delignification trajectory during kraft pulping, and the hypothesis that β—O—4 bonds splitting is mainly responsible for the delignification. However, some discrepancies between the current model, the previous model and experimental data are presented. These differences are discussed in the context of recent experimental findings indicating that β—O—4 bonds splitting might not entirely be responsible for the delignification due to mass transfer/solubility effects limitations.Peer reviewe