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A multicomponent synthesis of tetrahydroisoquinolines from carboxylic acids, alkynyl ethers, and dihydroisoquinolines is described. This process features readily available starting materials, simple experimental procedures for achievement of molecule complexity, and structural diversity. The preliminary control experiment and crossover reaction provide important insight into the reaction mechanism. The formed tetrahydroisoquinolines could be transformed to an array of compounds. [ABSTRACT FROM AUTHOR]

This study demonstrates the efficacy of a short-cut method such as the Global Minimization Algorithm (GMA),(1,2) that uses assumptions of ideal mixtures, constant molar overflow (CMO) and pinched columns, in pruning the search-space of distillation column configurations for zeotropic multicomponent separation, to provide a small subset of attractive configurations with low minimum heat duties. The short-cut method, due to its simplifying assumptions, is computationally efficient, yet reliable in identifying the small subset of useful configurations for further detailed process evaluation. This two-tier approach allows expedient search of the configuration space containing hundreds to thousands of candidate configurations for a given application. [ABSTRACT FROM AUTHOR]

In multivariate curve resolution (MCR) analysis, a range of feasible solutions is often encountered, because of the rotational ambiguities associated with the bilinear decomposition of data matrices. For quantitative purposes, the analysis is usually applied to a carefully designed set of calibration and test samples having uncalibrated interferents. Under the usual minimal constraints (non-negativity, unimodality, species correspondence, etc.), concentration and spectral profiles of the analyte in the test samples are not univocally recovered, unlike those in the calibration samples, especially when profile overlapping with the interferents is significant and selective regions do not exist for the analyte. In this report, a quantitative measure of the prediction errors due to rotational ambiguities is discussed, based on the calculation of the differences between the maximum and minimum area under the analyte concentration profiles calculated by the MCR-BANDS procedure. This methodology can be applied in different analytical scenarios with any number of analytes and interferents. Both absolute and relative quantitative errors due to rotation ambiguities are estimated and discussed in both simulated and experimental examples derived from liquid chromatography with diode array detection. The proposed procedure can be generalized to most of the analytical situations where every instrumentally measured sample produces a data table or data matrix. [ABSTRACT FROM AUTHOR]

The multicomponent synthesis of a mini-library of histone deacetylase inhibitors with imidazo[1,2-a]pyridine-based cap groups is presented. The biological evaluation led to the discovery of the hit compound MAIP-032 as a selective HDAC6 inhibitor with promising anticancer activity. The X-ray structure of catalytic domain 2 from Danio rerio HDAC6 complexed with MAIP-032 revealed a monodentate zinc-binding mode. [ABSTRACT FROM AUTHOR]

Chemical reactions on the surface or throughout a thermoplastic fiber present an interesting and challenging reaction engineering problem. This paper presents the design and implementation of a modular multiphase continuous stirred tank reactor for the sulfonation of polyethylene fibers. Polyethylene fiber tows, composed of 1000-6000 filaments, are sulfonated in a series of stirred tank reactors. Fundamental reaction engineering principles are applied to address common batch-to-continuous reactor challenges, such as heat and mass transfer, material balances, and reaction kinetics. The introduction of polymer fibers to a continuous process also requires the solution of practical problems associated with fiber processing. Additional considerations are introduced for designing a reactor system for continuous processing of fiber using liquid with a batch reactor or CSTR contacting pattern in each vessel and containing the effluent gaseous reaction byproducts in a controlled vent stream. The overall sulfonation reaction stoichiometry was determined such that ≈1 mol of SO3 reacts per mol of CH2 fed. Additionally, carbon sulfonation selectivity was determined to be 95-99%, depending on the sulfonation conditions. [ABSTRACT FROM AUTHOR]

This work is a continuation and extension of previously published study showing that the perturbed-chain statistical associating fluid theory (PC-SAFT) is an efficient and robust approach for calculating thermodynamic properties of the mixtures containing ionic liquids (ILs) [J. Phys. Chem. B 2012, 116, 5002–5018]. The modeling strategy presented in the original paper was based on application of infinite dilution activity coefficients of molecular solutes in ILs (γ∞) to calculate binary corrections for the PC-SAFT combining rules. In this work, the idea is further investigated, in particular extended to a broader spectrum of pure fluids (the model parametrization is provided for almost 100 ILs), and evaluated based on a large compilation of liquid–liquid equilibrium (LLE) data, including more than 400 distinct and diverse ternary systems and a number of higher systems. Three PC-SAFT modeling strategies are proposed and systematically reviewed in order to elucidate an effect of γ∞ data on the quality of LLE predictions. Experimental versus predicted impact of ILs’ cation and anion on LLE for different kinds of binary subsystems of molecular compounds is also highlighted and discussed. Finally, the results obtained with the PC-SAFT are confronted with the calculations carried out with conductor-like screening model for real solvents (COSMO-RS), often perceived or referred to as the state-of-the-art predictive tool of modern thermodynamics of liquid solutions. [ABSTRACT FROM AUTHOR]

At any given temperature, pressure, and composition, a compound or a mixture of compounds will exist either in a single phase, whether solid, liquid, or vapor, or in a combination of these phases coexisting in equilibrium. For multiphase systems, it is known that the geometry of the interface impacts the equilibrium state; this effect has been well-studied in single component systems with spherical interfaces. However, multicomponent phase diagrams are usually calculated assuming a planar interface between phases. Recent experimental and theoretical work has started to investigate the effect of curved interfaces on multicomponent phase equilibrium, but these analyses have been limited to isothermal conditions or to a portion of the isobaric phase diagram. Herein, we consider complete vapor-liquid phase diagrams (both bubble and dew lines) under isobaric conditions. We use Gibbsian composite-system thermodynamics to derive the equations governing vapor-liquid equilibrium for systems with a spherical interface separating the phases. We validate our approach by comparing the predicted nitrogen/argon dew points with reported literature data. We then predict complete isobaric phase diagrams as a function of radius of curvature for an ideal methanol/ethanol system and for a nonideal ethanol/water system. We also determine how the azeotropic composition of ethanol/water changes. The effect of curvature on isobaric phase diagrams is similar to that seen on isothermal phase diagrams. This work extends the study of curved-interface multicomponent phase equilibrium to isobaric systems, expanding the conditions under which nanoscale systems, such as nanofluidic systems, shale gas reservoirs, and cloud condensation nuclei, can be understood. [ABSTRACT FROM AUTHOR]

The continuous production of LaCrO3 particles (average edge size 639 nm, cube-shaped) by continuous hydrothermal flow synthesis using supercritical water is reported for the first time. By varying the reaction conditions, it was possible to suggest a reaction mechanism for the formation of this perovskite material. Moreover, dual-phase oxygen transport membranes were manufactured from the as-synthesized LaCrO3 particles and (ZrO2)0.89(Y2O3)0.01(Sc2O3)0.10 (10Sc1YSZ), and oxygen permeation fluxes up to 5 x 10-8 mol cm-2 s-1 were measured on a 1 mm thick membrane. [ABSTRACT FROM AUTHOR]

An algorithm is presented for constructing complete asphaltene PT phase diagrams. The algorithm works with any equation of state capable of providing consistent fugacity coefficients and appropriate derivatives for gas, oil, and asphaltene-rich phases. SRK, PC-SAFT, and CPA were successfully applied. The algorithm has been validated against multiphase PT flash calculations, and the results are further shown to agree with asphaltene simulation results in the open literature. Construction of the asphaltene PT phase diagram is fast and robust even in near-critical regions. Examples are shown illustrating the multitude of possible appearances of an asphaltene PT phase diagram. The algorithm has been modified to take an injection gas amount as specification, which allows for construction of asphaltene Px phase diagrams showing the response of phase boundaries to gas injection. Usage of the algorithm to get a full overview of the behavior of the asphaltene precipitation of the fluid is demonstrated. [ABSTRACT FROM AUTHOR]

Channeling of gas can reduce mass transfer performance in multiphase micropacked-bed reactors. Viscous and capillary forces cause this undesired and often unpredictable phenomenon in systems with catalyst particle sizes of hundreds of micrometers. In this work, we acoustically modify flow in a micropacked-bed reactor to reduce gas channeling by applying high-power sonication at low ultrasonic frequencies (~40 kHz). Experimental residence time distributions reveal two orders of magnitude reduction in dispersion with ultrasound, allowing for nearly plug-flow behavior at high flow rates in the bed. Sonication appears to partially fluidize the packed-bed under pressurized cocurrent two-phase flow, effectively improving dispersion characteristics. [ABSTRACT FROM AUTHOR]

The turbulence characteristics in the presence of bubbles is very important for multiphase processes such as froth flotation. The turbulence characteristics in an aerated Denver flotation cell were investigated using a high speed stereoscopic particle image velocimetry technique at single-phase (water) and two-phase (water and air) systems to provide insight into the change in liquid phase hydrodynamics. The effect of the gas flow rate (0.043-0.125 cms-1) and Reynolds number (107 000-154 000) on the fluid flow properties were investigated. The results showed that the flow pattern at the both systems was the radial-type flow. The presence of air bubbles changed the local turbulence characteristics (mean velocity, the root-mean-square velocity, turbulence kinetic energy dissipation, and turbulence kinetic energy). The results obtained may be useful for deeper investigation about the effect of the turbulence properties on the hydrodynamic characteristics and subprocesses in the mechanical flotation cells. [ABSTRACT FROM AUTHOR]

An analytical apparatus with improved recirculating and sampling mechanisms was presented to investigate phase behavior of binary and multicomponent systems, which effectively avoided undesirable pressure gradients across the cell and serious disturbance of equilibrium during sampling procedure. Two one-channel magnetic recirculation pumps were designed and built to provide better mass transfer between the coexisting phases. Two six-port switching valves were used for sampling, quantitative fluid injection, and online compositional analysis by gas chromatography. The apparatus was validated by means of isothermal vapor-liquid equilibrium data for CO2 + hexane, and the results were found to be in good agreement with the literature data. High pressure phase equilibria data of CO2 + n-alkanes and CO2 + crude oil + n-alkanes were measured from 353.15 to 373.15 K. Three thermodynamic models of RR, PRSV, and YQE, based on Peng-Robinson and a modified quartic equation of state coupled with various mixing rules, were suggested to represent phase equilibrium. Calculations were compared with experimental values for evaluating the predictive ability of these proposed equations. Analysis of the results confirmed that the YQE model was superior to all the other equations examined and worked well in describing phase behavior of complex real fluids. [ABSTRACT FROM AUTHOR]

A multiphase flow profile inside a helically coiled tubular device (HCTD) was observed by using a high-speed camera. Gas-liquid slug flow observations revealed that the Taylor vortices are influenced by secondary flow due to the centrifugal force acting perpendicular to the flow direction. Hence, mixing inside the liquid slug is enhanced by the combination of Dean and Taylor vortices in HCTD. The modular design of a specific type of HCTD, that is, the coiled flow inverter (CFI) is elucidated by the representation of a new design space diagram. Continuous precipitation of calcium carbonate (CaCO3) was investigated for modular CFI made of polyvinyl chloride (PVC) tubes (di = 3.2 mm) with slug flow patterns. CaCO3 was continuously precipitated along CFI with a conversion of ca. 90%. CFI provided a narrower particle size distribution with median particle diameters around 28 µm and more uniform morphology in comparison to a batch reactor. [ABSTRACT FROM AUTHOR]

Experimental data on the interfacial tension of ionic liquids in CO2 and CH4 atmospheres at elevated pressures (up to 20 MPa and 353 K) are presented and discussed. In addition, molecular modeling is utilized to describe the thermophysical properties under process-relevant conditions. Molecular modeling has the potential to predict findings in order to avoid costly experiments in the future and to explain the principal behavior of the whole system in terms of simulated concentration profiles. The interfacial tension is recognized to be an important quantity in a number of processes, e.g., for describing multiphase flow. By dissolving within the liquid phase, gases reduce the interfacial tension, which in turn is closely related to the phase behavior. It is shown that the experimentally determined interfacial tension, which decreases from values of 50 mN·m-1 under atmospheric conditions down to 10 mN·m-1 in CO2 but still above 30 mN·m-1 in CH4 at 10 MPa, is appropriately reflected by molecular dynamics (MD) simulations. The obtained data are analyzed in view of literature data and by using experimentally determined pressure-dependent densities and solubilities of CH4 and CO2 within ionic liquids. The results form part of a database for the ongoing development of MD simulations. [ABSTRACT FROM AUTHOR]

Droplet microfluidics generates and manipulates discrete droplets through immiscible multiphase flows inside microchannels. Due to its remarkable advantages, droplet microfluidics bears significant value in an extremely wide range of area. In this review, we provide a comprehensive and in-depth insight into droplet microfluidics, covering fundamental research from microfluidic chip fabrication and droplet generation to the applications of droplets in bio(chemical) analysis and materials generation. The purpose of this review is to convey the fundamentals of droplet microfluidics, a critical analysis on its current status and challenges, and opinions on its future development. We believe this review will promote communications among biology, chemistry, physics, and materials science. [ABSTRACT FROM AUTHOR]

Inverse Kirkwood-Buff (KB) solution theory can be used to relate macroscopic quantities with molecular scale interactions and correlation functions, in the form of KB integrals. Protein partial specific volumes (V2) from high-precision density measurements can be used to quantify solvent-solute and solute-solute KB integrals. Currently, general expressions for V2 as a function of cosolute concentration (c3) have been provided for only binary and ternary solutions. We derive a general multicomponent expression for V2 in terms of the relevant KB integrals for the case of low (infinite dilution) protein concentration but arbitrary cosolute concentrations. To test the utility of treating a quaternary system with a pseudoternary approximation, α-Chymotrypsinogen (aCgn) solutions with a series of solutes (NaCl, sucrose, and trehalose) were compared as a function of solute concentration with and without buffer present. Comparison between those ternary and quaternary solutions shows equivalent results within experimental uncertainty and suggests the pseudoternary approximation may be reasonable. In the case of aCgn, doing so also revealed that the preferential interactions can depend on pH. Analysis of steric contributions also provides an example that illustrates how KB integrals allow one to interpret V2 in terms of contributions from molecular volume, excluded volume, and hydration/solvation effects. [ABSTRACT FROM AUTHOR]

A new postcondensation multicomponent reaction (MCR) methodology, comprising oxidative deaminations enabling access to multiple privileged carbonyl-containing scaffolds in two steps, is described. These protocols allow facile access to functionalized α-ketoamide and α-ketotetrazole small-molecule peptidomimetic-like building blocks from prototypical synthons with two points of diversity. Incorporation of chalcone and alkynyl moieties with further ring-forming reactions enables access to additional novel heterocyclic ring systems, including a unique and potentially highly pharmacologically relevant scaffold, a 1,2-selenazol-3(2H)-one. [ABSTRACT FROM AUTHOR]

Separation and purification of gas mixtures using selective adsorbents is widely used in different industries such as gas drying, air separation, and H2 purification. Equilibrium analysis involving adsorption of binary gas mixtures provides important information related to the adsorbent performance in the separation of gases. In this study, a novel technique termed "differential column technique" was developed for binary isotherm measurement employing streams containing carbon dioxide, carbon monoxide, and ethylene at different compositions. This technique is based on measuring the gas desorption by changing equilibrium pressure conditions. The isotherm curve was generated by summing desorption amounts desorbed at each pressure step. Through the application of this technique, the single-component isotherms of CO2, CO, and ethylene on zeolite NaY were measured, and the isotherms were compared to the results obtained by a standard gravimetric technique. (The average relative deviation is less than 6%.) The main advantage of the technique is the significant time savings, e.g., one experimental run is required to generate an isotherm compared to multirun experiments using a standard breakthrough technique, in addition to using a simpler experimental setup and generally smaller amount of sample (agglomerated or in a powder form). Another important feature of this technique is the relatively simple extension that allows measurements of gas mixture equilibria. As such, the proposed technique has the potential to be used as a fast screening technique for adsorbent selection based on single-component or mixture analysis. To investigate the consistency of the proposed technique, the binary isotherms of competitive, CO2-C2H4, and noncompetitive, CO2-CO, mixtures were investigated at different gas compositions. In addition, the effects of sorbate concentrations in the gas phase and interactions with the NaY zeolite active surface were investigated in relation to the adsorption selectivity and capacity, i.e., strong interaction of both CO2 and ethylene with NaY site resulted in close adsorption selectivity 0.8 ≤ SCO2/C2H4 ≤ 1.7, while CO2 adsorbed more selectively compared to CO, 14 ≤ SCO2/CO ≤ 30, as a result of weak CO interaction with the adsorbent sites. Finally, the binary adsorption isotherms and selectivity were predicted by the multisite Langmuir model using the single component's isotherm parameters. Modest agreements (error ≤ 28%) were obtained between the predicted and experimental results. [ABSTRACT FROM AUTHOR]

The control of phase structuring in multiphase blends of polylactide (PLA) with other polymers is a viable approach to promote its broader implementation. In this article, ternary and quaternary blends of PLA with poly(butylene succinate) (PBS), poly(butylene adipate-co-terephthalate) (PBAT), and poly(3-hydroxybutyrate-co-hydroxyvalerate) (PHBV) are prepared by melt blending. The interfacial tensions between components are measured using three different techniques, and a Fourier transform infrared imaging technique is developed for the purpose of unambiguous phase identification. A tricontinuous complete wetting behavior is observed for the ternary 33PLA/33PBS/33PBAT blend before and after quiescent annealing, which correlates closely with spreading theory analysis. In the quaternary PLA/PBS/PBAT/PHBV blend, a concentration-dependent wetting behavior is found. At 10 vol % PBAT, self-assembled partially wet droplets of PBAT are observed at the interface of PBS and PHBV, and they remain stable after quiescent annealing as predicted by spreading theory. In contrast, at 25 vol % PBAT, a quadruple continuous system is observed after mixing, which only transforms to partially wet PBAT droplets after subsequent annealing. These results clearly indicate the potential of composition control during the mixing of multiphase systems to result in a complete change of spreading behavior. [ABSTRACT FROM AUTHOR]

Concentration is often an important process parameter in pharmaceutical crystallization processes. In this work, an ultra-performance liquid chromatography (UPLC) system designed for process monitoring (Waters PATROL UPLC) was applied online as a process analytical technology tool for real-time multicomponent concentration monitoring in pharmaceutical crystallization. Three online UPLC-based applications were investigated: (1) solute concentration monitoring during crystallizations and associated solubility, dissolution, and degradation analyses, (2) quick calibration for UV/vis and Raman spectroscopy, and (3) real-time crystallization product purity monitoring. [ABSTRACT FROM AUTHOR]

A model for gas-particle partitioning of polycyclic aromatic hydrocarbons (PAHs) was evaluated using polyparameter linear free energy relationships (ppLFERs) following a multiphase aerosol scenario. The model differentiates between various organic (i.e., liquid water-soluble (WS)/organic soluble (OS) organic matter (OM), and solid/semisolid organic polymers) and inorganic phases of the particulate matter (PM). Dimethyl sulfoxide and polyurethane were assigned as surrogates to simulate absorption into the above-mentioned organic phases, respectively, whereas soot, ammonium sulfate, and ammonium chloride simulated adsorption processes onto PM. The model was tested for gas and PM samples collected from urban and nonurban sites in Europe and the Mediterranean, and the output was compared with those calculated using single-parameter linear free energy relationship (spLFER) models, namely JungePankow, Finizio, and Dachs-Eisenreich. The ppLFER model on average predicted 96 ± 3% of the observed partitioning constants for semivolatile PAHs, fluoranthene, and pyrene, within 1 order of magnitude accuracy with root-mean-square errors (RMSE) of 0.35-0.59 across the sites. This was a substantial improvement compared to Finizio and Dachs-Eisenreich models (37 ± 17 and 46 ± 18% and RMSE of 1.03-1.40 and 0.94-1.36, respectively). The JungePankow model performed better among spLFERs but at the same time showed an overall tendency for overestimating the partitioning constants. The ppLFER model demonstrated the best overall performance without indicating a substantial intersite variability. The ppLFER analysis with the parametrization applied in this study suggests that the absorption into WSOSOM could dominate the overall partitioning process, while adsorption onto salts could be neglected. [ABSTRACT FROM AUTHOR]

Dew point specifications are of high interest in the natural gas industry. The CPA equation of state (EoS) was previously validated against both water content and phase equilibrium data. Moreover, solid model parameters were estimated for four natural gas main components (methane, ethane, propane, and carbon dioxide). In this study we have extended the use of CPA EoS to perform equilibrium temperature calculations for natural gas main components with (mono-)ethylene glycol (MEG) as an inhibitor. The ternary systems with aqueous MEG solution include methane, ethane, propane, carbon dioxide, and hydrogen sulfide. The quaternary systems with aqueous MEG solution include methane + ethane, methane + propane, methane + n-heptane, and methane + n-octane. Three multicomponent systems (>4 components) were also studied. The temperature range of the literature data is between 241.25-333.15 K, and the pressure range is between 0.1-24.8 MPa. The results in all cases are compared against experimental data, and very good agreement with experimental data is obtained. [ABSTRACT FROM AUTHOR]

Self-assembly of a stereodynamic phosphine ligand, Pd(II), and a chiral amine, amino alcohol, or amino acid generates characteristic UV and CD signals that can be used for quantitative stereochemical analysis of the bound substrate. A robust mix-and-measure chiroptical sensing protocol has been developed and used to determine the absolute configuration, ee, and yield of an amine produced by Ir-catalyzed asymmetric hydrogenation of an iminium salt. The analysis requires only 1 mg of the crude reaction mixture and minimizes cost, labor, time, and waste. [ABSTRACT FROM AUTHOR]

Adsorptive separation techniques such as pressure swing adsorption can be employed on a large scale to separate and purify hydrogen. The streams of hydrogen are multicomponent mixtures of H2, CO2, CO, and CH4. Competitive isotherms of adsorption of a multicomponent gas mixture (CO2, CO, CH4, and H2) on two commercial sorbents (activated carbon and 5A zeolite granules) are presented in this work. Adsorption equilibrium is investigated in a wide range of pressure (1 to 18 bar) at three temperatures (25, 35, and 45 °C). A study has been performed on the loading ratio correlation and Langmuir models for the adsorption. The adsorption capacity of different components of the gas mixture on activated carbon follows the order CO2 < CH4 < CO < H2, and the adsorption capacity order for the zeolite is CO2 < CO < CH4 < H2. The loading amount of carbon dioxide on zeolite 5A increases quickly at low pressure, and disruption at these pressures is hard. Hence, carbon dioxide should not reach into the zeolite layer. For activated carbon, the Langmuir model fit the data with fairly good accuracy within the operating conditions studied. Both models were able to fit the experimental data for zeolite 5A with good accuracy. [ABSTRACT FROM AUTHOR]

In process analytics, the applicability of Raman spectroscopy is restricted by high excitation intensities or the long integration times required. In this work, a novel Raman system was developed to minimize photon flux losses. It allows specific reduction of spectral resolution to enable the use of Raman spectroscopy for real-time analytics when strongly increased sensitivity is required. The performance potential of the optical setup was demonstrated in two exemplary applications: First, a fast exothermic reaction (Michael addition) was monitored with backscattering fiber optics under strongly attenuated laser power (7 mW). Second, high-speed scanning of a segmented multiphase flow (water/toluene) with submicroliter droplets was achieved by aligning the focus of a coaxial Raman probe with long focal length directly into a perfluoroalkoxy (PFA) capillary. With an acquisition rate of 333 Raman spectra per second, chemical information was obtained separately for both of the rapidly alternating phases. The experiment with reduced laser power demonstrates that the technique described in this paper is applicable in chemical production processes, especially in hazardous environments. Further potential uses can be envisioned in medical or biological applications with limited power input. The realization of high-speed measurements shows new possibilities for analysis of heterogeneous phase systems and of fast reactions or processes. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed multicomponent reaction (MCR) involving aryne, CO, and aniline is established for straightforward assembly of a phenanthridinone scaffold through C-H bond activation. Free combination with multiple kinds of readily available anilines and arynes is facilely achieved for phenanthridinone construction without prefunctionalization. Representative natural products were subsequently synthesized through this MCR strategy highly efficiently. Control experiments and interval NMR tracking revealed the mechanism, particularly the key role of CuF2 in determining the aryne-releasing rate from the precursor in this transformation. [ABSTRACT FROM AUTHOR]

Materials work in multicomponent forms. A wide range of compositions must be tested to obtain the optimum composition for a specific application. We propose optimization using a series of small levitated single particles. We describe a tandem-trap apparatus for merging liquid droplets and analyzing the merged droplets and/or dried particles that are produced from the merged droplets under levitation conditions. Droplet merging was confirmed by Raman spectroscopic studies of the levitated particles. The tandem-trap apparatus enables the synthesis of a particle and spectroscopic investigation of its properties. This provides a basis for future investigation of the properties of levitated single particles. [ABSTRACT FROM AUTHOR]

The accurate prediction of the conditions of a pressurized jet upon its expansion to atmospheric pressure is of fundamental importance in assessing the consequences associated with accidental releases of hazardous fluids from pressurized containments. An integral multiphase compressible jet expansion model which for the first time accounts for turbulence generation is presented. Real fluid behavior is accounted for applying a suitable equation of state. By use of the accidental release of two-phase CO2 from a pressurized system as an example, the proposed model is shown to provide far better predictions of the fully expanded jet momentum and hence its downstream flow characteristics as compared to existing integral models where the impact of turbulence generation is ignored. [ABSTRACT FROM AUTHOR]

Three-phase processes in which particle suspension has to be achieved in conjunction with gas dispersion are traditionally carried out in sparged, baffled stirred tanks. The operation of such tanks can suffer, however, from particles tending to block the sparger holes. A viable alternative might be provided by uncovered unbaffled stirred tanks (UUSTs), where gas self-injection can occur when the free-surface vortex reaches the impeller blades and gas bubbles begin to be ingested by the liquid. In this work, the particle suspension and liquid aeration performances in three-phase UUSTs were experimentally investigated and compared with relevant literature correlations concerning baffled systems. The results show that, at least at the investigated scale, UUSTs are more efficient for suspending particles than relevant baffled systems. Impeller clearance scarcely affects power requirements. Finally, a down-pumping PBT with D/T = 1/3 was found to be the best choice for attaining complete suspension under self-aeration conditions. [ABSTRACT FROM AUTHOR]

The solid-liquid phase equilibrium for the ternary succinic acid + adipic acid + ethanol system was determined at 283.15, 303.15, and 313.15 K, respectively, under about 101.3 kPa. The mutual solubility for the ternary system were obtained. At each temperature, there existed two pure solid phases in the ternary system, which were pure succinic acid and pure adipic acid, and identified by the Schreinemaker's wet residue method and X-ray diffraction (XRD) pattern. The crystallization region of adipic acid was a little smaller than that of succinic acid at a certain temperature. The solid-liquid phase equilibrium for the ternary system was correlated and calculated by using the Wilson and NRTL models, and the corresponding binary interaction parameters were acquired. Results showed that calculated solubility values with NRTL model agreed better than those with the Wilson model. In addition, the densities of the equilibrium liquor were obtained and correlated with an empirical equation. The mutual solubility and the phase diagram for the ternary system are helpful in separating of succinic acid and adipic acid mixtures. [ABSTRACT FROM AUTHOR]

Confined fluids such as oil and gas mixtures inside tight reservoirs are systems that can experience high capillary pressure difference between the liquid and gas phases. This capillary pressure difference has an effect on the phase equilibrium and in some cases is considerably high. We presented an algorithm which can reliably compute the whole phase envelope for multicomponent mixtures when there is a capillary pressure difference. It uses an equation of state for the phase equilibrium and the Young-Laplace equation for the capillary pressure model. The algorithm proves to be robust and efficient for test mixtures with wide ranges of compositions at different capillary radii and vapor fractions. The calculation results show that the phase envelope changes everywhere except at the critical point. The bubble point and the lower branch of the dew point show a decrease in the saturation pressure, whereas the upper branch of the dew point shows an increase. The cricondentherm is shifted to a higher temperature. We also presented a mathematical analysis of the phase envelope shift due to capillary pressure based on linear approximations. The resulting linear approximation equations can predict the correct direction of the phase envelope shift. Combined with the multicomponent Clapeyron equation, the equations reveal why the shift changes direction for the saturation pressure at the cricondentherm and for the saturation temperature at the cricondenbar. The equations can be used to estimate the magnitude of shift, and the approximation is close for the change in the bubble point pressure. [ABSTRACT FROM AUTHOR]

As a novel research issue, the operating performance assessment for industrial processes has received growing interest in recent years. In this study, a multiple hypotheses testing-based operating optimality assessment and nonoptimal cause identification method is proposed to handle the online assessment of the batch processes with multiphase and uneven-length characteristics. A new Gaussian mixture model (GMM)-based offline phase division procedure is proposed. Compared to the existing methods, it can not only ensure that each phase contains the consecutive sampling instants but can also retain the characteristics of phase-uneven-length for retaining more-accurate phase information. The extra post-processing is not needed in phase division, and the assessment models of each phase are set up along with it. In online application, both the local and global online assessments are performed for a new batch based on the multiple hypotheses testing technology by controlling the false discovery rate. For the nonoptimal batch, the cause variables can be determined based on the variable contributions to the assessment index. Finally, the effectiveness of the proposed method is verified through a fed-batch penicillin fermentation process. [ABSTRACT FROM AUTHOR]

The effect of interface curvature on phase equilibrium has been much more studied for single-component than multicomponent systems. We isolate the effect of curvature on multicomponent vapor-liquid equilibrium (VLE) phase envelopes and phase composition diagrams using the ideal system methanol/ethanol and the nonideal system ethanol/water as illustrative examples. An important finding is how nanoscale interface curvature shifts the azeotrope (equal volatility point) of nonideal systems. Understanding of the effect of curvature on VLE can be exploited in future nanoscale prediction and design. [ABSTRACT FROM AUTHOR]

Predesigned complementary complexation of two 2,2':6',2?-terpyridine-based ligands was established by installing 2,6-dimethoxyphenyl substituents at the terpyridyl 6,6?-positions, which provided ancillary ion–dipole interactions in the coordination process and extra π-stacking stabilization in the resultant heteroleptic complex. The high-fidelity self-recognition ligation afforded facile access to the quantitative self-assembly of multicomponent triangle [Cd6L33L43] and ditrigon [Cd15L36L53] (that is, a hexagon with six 120° angles and two alternating edge lengths). It was found that the linear 6,6?-substituted ditopic motif (L3) would be directed by the ligand geometry of L5 to selectively incorporate into the parallel homoleptic connections in the bilayered framework. [ABSTRACT FROM AUTHOR]

An acid-catalyzed multicomponent tandem cyclization protocol has been developed for the synthesis of polyfunctional dihydroindolizino[8,7-b]indoles from simple and readily available arylglyoxal monohydrates, tryptamines, and trans-β-nitrostyrenes or malononitrile. This reaction represents a highly efficient and convenient methodology for the synthesis of diversely substituted heteropolycyclic scaffolds under mild, metal-free conditions. [ABSTRACT FROM AUTHOR]

The multicomponent (binary and ternary) adsorption equilibria of three volatile organic compounds (VOCs) (acetone, toluene, and n-hexane) on activated carbon were studied under supercritical carbon dioxide (scCO2) conditions. The multicomponent adsorption equilibrium data were obtained at 313-353 K and 4.2-10.0 MPa and depended on the affinities of the adsorbates for the adsorbent. The amounts of adsorbed VOCs decreased with increases in the pressure and decreases in the temperature, owing to the effects of the CO2 density. The measured adsorption equilibria were correlated within 5.5% of the average relative deviation to the Dubinin-Astakhov equation using two parameters. These parameters, which were determined based on these correlations, provided information on the multicomponent adsorption equilibria of the VOCs under scCO2 conditions while considering the interactions between the VOCs and the adsorbent, the bulk phase CO2 density, and the competitive adsorption of the VOCs and CO2 in the adsorbed phase. [ABSTRACT FROM AUTHOR]

The Group Contribution with Association Equation of State (GCA-EoS) has been successfully applied to represent the global phase behavior of carbon dioxide mixtures with alkanes. Using a single set of parameters, the model is able to predict vapor-liquid and liquid-liquid equilibria of binary mixtures not included in the parametrization procedure. Special emphasis was set on describing the transformation between types of fluid phase behavior to reduce the jeopardy of predicting incorrect liquid split. This family of binary systems has been investigated in previous works; however, this is the first time that GCA-EoS was shown to be able to represent the transformation between types of phase behavior as the length of the alkyl chain increases. The model was tested against an experimental database covering C3-C36 alkanes, temperatures from 210 to 660 K, and pressures up to 400 bar. The wide range of conditions and the parametrization strategy are keys to develop a robust thermodynamic tool for predicting multiphase behavior. [ABSTRACT FROM AUTHOR]

Cuckoo Search (CS), which is a nature-inspired stochastic optimization method, has been successfully applied for estimating binary interaction parameters of universal quasichemical (UNIQUAC) and nonrandom two-liquid (NRTL) activity coefficient models for liquid-liquid ternary systems involving 12 imidazolium and phosphonium ionic liquids (ILs). Thirty-nine ternary systems, comprising 371 experimental tie-lines, were correlated by the UNIQUAC and NRTL models. The results, expressed by deviations between experimental and calculated mole fractions, are very satisfactory, with global deviation values of 0.0053 (UNIQUAC) and 0.0072 (NRTL), which are 63% and 45% better than literature reported values. Three quaternary systems and one quinary system were taken from literature to compare the capability of CS algorithm with genetic algorithm (GA) and particle swarm optimization (PSO) algorithm. The global % root-mean-square deviation (RMSD) value obtained with CS algorithm was ~0.14-0.85% as compared to ~1.0-2.0% with GA and PSO algorithms. This shows a higher efficiency for the CS algorithm in solving global optimization problems involved in the thermodynamic modeling of multicomponent systems. [ABSTRACT FROM AUTHOR]

This work introduces a multiobjective optimization approach to integrate the design and control of multicomponent distillation sequences. The evaluation of the control properties and the design of the distillation systems were evaluated through the calculation of the condition number and the total annual cost of each design, respectively. Three distillation systems, including the direct sequence, the indirect sequence, and the dividing wall column along with three mixtures with representative ease of separation index (ESI) values and three different feed compositions, were studied. In addition, in a posterior stage to the optimization process, the Eco-indicator 99 for each design was estimated to quantify the environmental impact of the distillation systems. The results offer the trade-offs between the control properties and the design, which is shown through Pareto optimal solutions that enable selection of the solutions that establish the proper balances between both objectives. [ABSTRACT FROM AUTHOR]

Multicomponent Langmuir monolayersare important models of organiccoatings of naturally occurring water–vapor interfaces suchas the surfaces of oceans or aerosol particles. We investigated mixedmonolayers comprised of palmitic acid, C15H31COOH (PA) and 1-bromoalkanes of different chain length (C5, C10, and C16) at the air–water interfaceemploying classical molecular dynamics simulations. Different compositionratios and lateral compression of the monolayers were considered.The structural parameters, such as density profiles, and deuteriumorder parameter, evaluated as functions of composition and the lateralfilm packing, provide microscopic information about organization anddynamics of the mixed monolayers. Simulations demonstrate that stableand well mixed monolayers are formed by the mixtures of PA and BrC16H33(BrCl6), whereas the two considered shorterbromoalkanes, BrC5H11(BrC5) and BrC10H21(BrC10), do not form stable films. This is in accordwith earlier experimental studies. Under high lateral pressures, inPA/BrC10 mixed systems molecules of the bromoalkane readily flip inthe monolayer and subsequently leave the film, while the moleculesof the longer BrC16 are expelled from the PA film but no flippingoccurs. These results suggest that the film collapse under pressureis preceded by squeezing-out of bromoalkanes from the PA monolayer. [ABSTRACT FROM AUTHOR]

This paper deals with the phenomenologicalcharacteristics of themultiphase flow in a 3D urea prilling tower under conditions closeto those of the industrial-scale process, considering the simultaneousheat and momentum transfer and the droplet solidification, using thecomputational fluid dynamics technique. The Euler–Lagrangeapproach is used to represent the multiphase flow. Solidificationof the droplets was considered by means of an unsolidified core model,which predicts the thickness of the solid phase formed from the surfaceto the center of the droplets during the evolution of their trajectoriesin the continuous phase. The global operational performance of theprocess was evaluated on the basis of the solidification and breakingindexes defined from local variables obtained from numerical simulations.Solidification index values in the range of 0.83–1.00 wereobtained from simulations, and the internal resistance to heat transferwas found to strongly affect the solidification phenomenon. A nonsymmetricalflow was used to evaluate the breaking index of droplets broken becauseof impact with the walls. The global thermal properties associatedwith the droplets, i.e., the surface and core temperatures and theoverall heat-transfer coefficient, had values of 34.37 °C, 115.79°C, and 19.29 W/m2K, respectively, for droplets witha diameter of 1.2 mm. The air temperature at the top of the towerwas 74.26 °C for droplets of this diameter. [ABSTRACT FROM AUTHOR]

Emulsionsare multiphasic fluid systems in which liquid dropletsare dispersed in another immiscible liquid. The main components ofan emulsion are the two liquid phases, typically oil and water, andthe emulsifier, which stabilizes the interface between the two liquidphases. Emulsifiers can be a variety of molecules, such as polymers,amphiphilic surfactants, and proteins, and they can also be colloidalparticles. Emulsion phase inversion is the process of interconversionbetween two types of simple emulsions: water-in-oil and oil-in-wateremulsions. Phase inversion can be induced by shifting the emulsifieraffinity from one phase to the other, which is called transitionalphase inversion. It can also be triggered by a change in the water-to-oilratio of the emulsion, which leads to a process known as catastrophicphase inversion. With recent advances in the stabilization of emulsionsusing colloidal particles and stimuli-responsive surfactants, numerousnovel emulsion systems that undergo emulsion phase inversion by meansof various mechanisms have been developed. In this review, we highlightthe most recent developments in the field of emulsion phase inversion,focusing on transitional phase inversion, inversion of particle-stabilizedemulsions, and flow- and shear-induced phase inversion. We also discussand compare state-of-the-art analytical methods that have been usedto detect and understand the emulsion phase inversion process. Ourcoverage spans from the early concepts of Bancroft’s rule throughthe concept of semiquantitative hydrophilic–lipophilic balanceto the more recent theoretical models used to predict and controlphase inversion phenomena. We conclude this review by presenting anoutlook on the future directions and outstanding problems that warrantfuture investigations to fully understand the mechanism of emulsionphase inversion at the single-droplet level. [ABSTRACT FROM AUTHOR]

Traditional descriptions of gas-particle partitioning of organic aerosols (OA) rely solely on thermodynamic properties (e.g., volatility). Under realistic conditions where phase partitioning is dynamic rather than static, the transformation of OA involves the interplay of multiphase partitioning with oxidative aging. A key challenge remains in quantifying the fundamental time scales for evaporation and oxidation of semivolatile OA. In this paper, we use isomer-resolved product measurements of a series of normal-alkanes (C18, C20, C22, and C24) to distinguish between gas-phase and heterogeneous oxidation products formed by reaction with hydroxyl radicals (OH). The product isomer distributions when combined with kinetics measurements of evaporation and oxidation enable a quantitative description of the multiphase time scales to be simulated using a single-particle kinetic model. Multiphase partitioning and oxidative transformation of semivolatile normal-alkanes under laboratory conditions is largely controlled by the particle phase state, since the time scales of heterogeneous oxidation and evaporation are found to occur on competing time scales (on the order of 10-1 h). This is in contrast to atmospheric conditions where heterogeneous oxidation time scales are expected to be much longer (on the order of 10² h), with gas-phase oxidation being the dominant process regardless of the evaporation kinetics. Our results demonstrate the dynamic nature of OA multiphase partitioning and oxidative aging and reveal that the fundamental time scales of these processes are crucial for reliably extending laboratory measurements of OA phase partitioning and aging to the atmosphere. [ABSTRACT FROM AUTHOR]

The recently developed artificial force induced reaction (AFIR) method was applied to search systematically all possible multicomponent pathways for the Biginelli reaction mechanism. The most favorable pathway starts with the condensation of the urea and benzaldehyde, followed by the addition of ethyl acetoacetate. Remarkably, a second urea molecule catalyzes nearly every step of the reaction. Thus, the Biginelli reaction is a urea-catalyzed multicomponent reaction. The reaction mechanism was found to be identical in both protic and aprotic solvents. [ABSTRACT FROM AUTHOR]

To demonstrate key roles of multipleinteractions between multiplecomponents and multiple phases in the formation of an uncommon self-assemblingpattern, we present here the construction of a porous hexagonal star(h-star) structure using a trigonal molecular buildingblock at the liquid/solid interface. For this purpose, self-assemblyof hexaalkoxy-substituted dehydrobenzo[12]annulene derivatives DBA-OCns was investigated at the tetradecane/graphite interfaceby means of scanning tunneling microscopy (STM). Monolayer structureswere significantly influenced by coadsorbed tetradecane moleculesdepending on the alkyl chains length (C13–C16) of DBA-OCn. However, none of DBA-OCnmolecules formed the expected trigonal complexes, indicatingthat an additional driving force is necessary for the formation ofthe trigonal complex and its assembly into the h-starstructure. As a first approach, we employed the “guest inducedstructural change” for the formation of the h-star structure. In the presence of two guest molecules, nonsubstitutedDBA and hexakis(phenylethynyl)benzene which fit the respectivepores, an h-star structure was formed by DBA-OC15at the tetradecane/graphite interface. Moreover, a tetradecane moleculewas coadsorbed between a pair of alkyl chains of DBA-OC15, therebyblocking the interdigitation of the alkyl chain pairs. Therefore,the h-star structure results from the self-assemblyof the four molecular components including the solvent molecule. Thesecond approach is based on aggregation of perfluoroalkyl chains viafluorophilicity of DBA-F, in which the perfluoroalkyl groups are substitutedat the end of three alkyl chains of DBA-OCnvia p-phenylene linkers. A trigonal complex consisting of DBA-Fand three tetradecane molecules formed an h-starstructure, in which the perfluoroalkyl groups that orient into thealkane solution phase aggregated at the hexagonal pore via fluorophilicity.The present result provides useful insight into the design and controlof complex molecular self-assembly at the liquid/solid interface. [ABSTRACT FROM AUTHOR]

Planktonic metabolism plays crucial roles in Earth's elemental cycles. Chemical speciation as well as elemental stoichiometry is important for advancing our understanding of planktonic roles in biogeochemical cycles. In this study, a multicomponent solid-state nuclear magnetic resonance (NMR) approach is proposed for chemical speciation of cellular components, using several advanced NMR techniques. Measurements by ssNMR were performed on 13C and 13N-labeled Euglena gracilis, a flagellated protist. 3D dipolar-assisted rotational resonance, double-cross-polarization 1H-13C correlation spectroscopy, and 1H-13C solid-state heteronuclear single quantum correlation spectroscopy successively allowed characterization of cellular components. These techniques were then applied to E. gracilis cultured in high and low ammonium media to demonstrate the power of this method for profiling and comparing cellular components. Cellular NMR spectra indicated that ammonium induced both paramylon degradation and amination. Arginine was stored as a nitrogen reserve and ammonium replaced by arginine catabolism via the arginine dihydrolase pathway. 15N and 31P cellular ssNMR indicated arginine and polyphosphate accumulation in E. gracilis, respectively. This chemical speciation technique will contribute to environmental research by providing detailed information on environmental chemical properties. [ABSTRACT FROM AUTHOR]

Multicomponent quantum mechanical(MC_QM) calculations with polarizablecontinuum model (PCM) have been tested against liquid 1H NMR chemical shifts for a test set of 80 molecules. Improvementfrom conventional quantum mechanical calculations was achieved forMC_QM calculations. The advantage of the multicomponent scheme couldbe attributed to the geometrical change from the equilibrium geometryby the incorporation of the hydrogen nuclear quantum effect, whilethat of PCM can be attributed to the change of the electronic structureaccording to the polarization by solvent effects. [ABSTRACT FROM AUTHOR]

Multicomponent construction of the tetrakis(spiroborate) anionic nanocycles was achieved by reacting bis(dihydroxynaphthalene)s with tetrahydroxyanthraquinone in the presence of boric acid in a self-organized manner. These nanocycles exhibited selective molecular recognition behavior toward cationic guests such as methyl viologen derivatives. Formation of a supramolecular ring@ring and a guest@ring@ring structure was observed by combining the anionic nanocycle and the vinylogous analog of cyclobis(paraquat-p-phenylene). [ABSTRACT FROM AUTHOR]

Toprevent hydrate plugging conditions in the transportation ofoil/gas in multiphase flowlines, one of the key processes to controlis the agglomeration/deposition of hydrate particles, which are determinedby the cohesive/adhesive forces. Previous studies reporting measurementsof the cohesive/adhesive force between hydrate particles used cyclopentanehydrate particles in a low-pressure micromechanical force apparatus.In this study, we report the cohesive forces of particles measuredin a new high-pressure micromechanical force (MMF) apparatus for iceparticles, mixed (methane/ethane, 74.7:25.3) hydrate particles (StructureII), and carbon dioxide hydrate particles (Structure I). The cohesiveforces are measured as a function of the contact time, contact force,temperature, and pressure, and determined from pull-off measurements.For the measurements performed of the gas hydrate particles in thegas phase, the determined cohesive force is about 30–35 mN/m,about 8 times higher than the cohesive force of CyC5hydratesin the liquid CyC5, which is about 4.3 mN/m. We show fromour results that the hydrate structure (sI with CO2hydratesand sII with CH4/C2H6hydrates) hasno influence on the cohesive force. These results are important inthe deposition of a gas-dominated system, where the hydrate particlesformed in the liquid phase can then stick to the hydrate depositedin the wall exposed to the gas phase. [ABSTRACT FROM AUTHOR]

The handling of multiphase systems applied in mixer-settler processes, in which phase separation characteristics are exploited, is to date still a challenge for the chemical industry. Approaches for analyzing the influencing parameters on these systems can be of use, especially regarding equipment design and technical applicability. In this contribution, a guideline is presented and applied in a case study for a surfactant-containing multiphase system implemented in a hydroformylation mini-plant. Herein, the most relevant investigated parameters such as temperature, concentrations of reactants, system pressure, and stirrer characteristics are analyzed. This is followed by an analysis of various internal fittings including their influence on the temperature profile within the settler. The results of the systematic analysis are used to design a highly flexible, modular, and efficient settler for the separation of up to three liquid phases. [ABSTRACT FROM AUTHOR]