Liquid-liquid Two-phase System Research Articles

A method of predicting the two-phase liquid-liquid flow resistance in a horizontal pipe with a layer of metal foam

The study reported here is experimental. Its aim was to determine the method applicable for prediction of pressure losses of an unstable two-phase liquid-liquid system flow through a horizontal pipe with a short section of the pipe containing a metal foam packing. However, the flow disturbance resulting from the presence of foam does not lead to a change in the type of the mixture (as there is no phase inversion) nor a permanent emulsification of the flow system. The calculation procedure developed in the study takes into account both the peculiarities that accompany the flow of a two-phase liquid-liquid system in an empty pipe (i.e. type of continuous phase, phase slip, hold-up), as well as geometric parameters of the foam skeleton (i.e. cell and pore dimensions, surface roughness of fibers). The results of experimental research were applied for the purposes of determining the specific form of the equations, consistent with the mathematical model adopted and described in detail in this paper. They were conducted for two foams: aluminum and nickel, which were characterized by the same degree of pore packing (PPI20). The mean dimensions of the elements forming metal foams skeletons were determined by computed tomography. The horizontal flow tube had a diameter of 10 mm and the foam packing occupied it only over a a section with a certain length. In the liquid-liquid system pumped to the pipe, the hydrophilic phase was tap water, while the hydrophobic phase was typical machine oil. The adopted range of flux changes of both liquids corresponded to the conditions at which unstable two-phase systems of the W/O, O/W and W+O type were formed in the empty pipe. The pressure loss of the flowing substance was measured in the foam layer. The values of constants and exponents of the adopted model equation were determined separately for single-phase flow and two-phase systems of various types. The results of the statistical evaluation of the performance of the developed dependencies justify their application in the design procedures of selected heat or mass transfer devices. The equations are dimensionless, and therefore, under the conditions of validity, they should also be effective for other liquid-liquid systems, other foams and flow in a pipe with a different diameter. The developed method is based on a new approach to the description of the two-phase flow resistance through the porous material filling the pipe. In addition, it concerns the flow of a liquid-liquid system, which still forms the area that has been tackled in few publications.

Synthesis of novel polymer quaternary ammonium salt derived from glucose as a phase transfer catalyst

Abstract. Alrubaie I, Salim AT, Majeed MM, Radhi AJ. 2022. Synthesis of novel polymer quaternary ammonium salt derived from glucose as a phase transfer catalyst. Nusantara Bioscience 14: 25-33. Some new polymer containing quaternary ammonium salts based-carbohydrate starting from methyl-4,6-O-benzylidene-glucopyranoside have been prepared. The ammonium groups are connected to the glucose structure in various positions (2 and 3). Our synthesis used methyl-4,6-O-benzylidene-a-D-glucopyranoside through nucleophilic reagents to produce the main intermediates. The monomer glucose- quaternary ammonium salts are immobilized on the polyvinyl azide to give the final structure of the Polymer-Supported quaternary ammonium salts. In certain new kinds of phase transfer catalysts, the effectiveness of the polymer glucose-quaternary ammonium salts was tested in the Williamson etherification. The ether synthesis is a typical example of using a phase transfer catalyst. The reactions were performed in a liquid-liquid two-phase system, applying a mixture of toluene and 50% solution of aqueous sodium hydroxide in the presence of a 20 mg/mmol catalyst (compound 9). Compared to other derivatives, the reaction of 4-nitrophenol with dibromoethylene gives the highest yields. On the other hand, compound 9 with the C16 chain gives high activity in the phase transfer catalyst.

Boron isotope separation by extraction method: features of the phase composition and flow reflux

The publication is devoted to comprehensive studies of boron isotope exchange in two-phase liquid-liquid systems and reflects the features of the extraction separation of boron isotopes, including reagent-free phase flow reflux. The achieved experimental values of the single stage enrichment factor are commensurate with the analogous values for the main production technologies ofr the 10B concentrating, and the reagent-free version of the flow reflux determines the competitiveness of such process. The method is considered an alternative to ion exchange and liquid chromatography, and, possibly, chemical exchange with the participation of boron trifluoride.

Behaviour of liquid-liquid two-phase flow pattern and mass transfer with combined incorporation of fully pulsatile flow and variable volume of air suspension

The application of fully pulsatile flow in liquid-liquid two-phase extraction contributes to augment the interfacial mass transfer. Further, the inclusion of air at the top of the central test section combined with pulsatile flow augments the extraction or the mass transfer process. Toluene-water is chosen as an organic-aqueous two-phase liquid-liquid system with acetic acid as the transfer species which is added in dilute quantities 10 percentage by volume to the organic phase and the transfer of the same to the aqueous phase is recorded with the help of refractive index (RI) measurements. The RI is converted to an overall volumetric mass transfer coefficient with the help of a formula derived for the system. Experiments have been conducted for pulsatile flow with T junction having no air at the top and with variable volume 5, 10, 12, and 14 cm3 of air at the top of the cross junction. The results of mass transfer coefficients were compared and it was found that inclusion of air combined with flow pulsation leads to a higher degree of extraction in comparison to without pulsation and pulsatile flow with no air at the top. Also, the in-phase mode of pulsation with 2.5 Hz of frequency leads to enhanced extraction and a broader plug flow regime.

Multi-dimensional analysis of turbulence models for immiscible liquid-liquid mixing in stirred tank based on numerical simulation

ABSTRACT The Reynolds Averaged Navier-Stokes (RANS) simulation was employed to predict a turbulent flow of liquid-liquid two-phase system in standard stirred tank. The results calculated by the standard k-ε model and the Renormalization Group (RNG) k-ε model were compared to Particle Image Velocimetry (PIV) data from the literature. The constants of the transports equations were corrected, which could reflect the time-averaged strian rate of the main flow. Multi-dimensional investigation revealed the flaws of RNG k-ε model compared to standard k-ε model in predicting the liquid-liquid two-phase mixing process, which has great guidance for the selection of the turbulence models.

Efficient enzyme-assisted extraction of genipin from genipap (Genipa americana L.) and its application as a crosslinker for chitosan gels

Enzyme-assisted extraction in liquid-liquid two-phase aqueous system was applied for the first time in order to extract genipin from genipap. The effect of different commercial enzymes, their concentrations, and extraction parameters were investigated. Moreover, chitosan gels were prepared, crosslinked with glutaraldehyde or genipin and characterized by their textural and rheological properties. The crosslinked chitosan was used as support for the immobilization of model β-galactosidases. Among the different commercial enzymes tested for extraction, Celluclast 10% (36 °C and pH 3.7) provided an extraction of 196 mg.g−1 of genipin. Chitosan gels crosslinked with genipin 0.5% showed better textural and similar rheological properties when compared to the chitosan crosslinked with glutaraldehyde 3%. The percentage of lactose hydrolysis by the immobilized K. lactis β-galactosidase using genipin as a crosslinker was 87%. Thus, the genipin obtained in this work proved to be an excellent alternative to the use of glutaraldehyde in chitosan crosslinking applications.

Energetic Efficiency of Mixing and Mass Transfer in Single Phase and Two-Phase Systems

Abstract In this work a concept of energetic efficiency of mixing is presented and discussed; a classical definition of mixing efficiency is modified to include effects of the Schmidt number and the Reynolds number. Generalization to turbulent flows is presented as well. It is shown how the energetic efficiency of mixing as well as efficiencies of drop breakage and mass transfer in twophase liquid-liquid systems can be identified using mathematical models and test chemical reactions. New expressions for analyzing efficiency problem are applied to identify the energetic efficiency of mixing in a stirred tank, a rotor stator mixer and a microreactor. Published experimental data and new results obtained using new systems of test reactions are applied. It has been shown that the efficiency of mixing is small in popular types of reactors and mixers and thus there is some space for improvement.

Ionic Liquid|Water Interface As an Electrochemical Reaction Field for the Formation of Novel Metal Nanostructure

Electrochemistry at interface between two immiscible electrolyte solutions (ITIES) has been explored in the novel liquid-liquid two-phase system of water (W) and ionic liquids (ILs) since more than a decade ago [1,2]. One of several characteristics of ILs is the ability to disperse and stabilize metal nanostructures in ILs without addition of any capping reagents, which seems to result from the existence of ionic multilayers [3,4], a rigid interfacial structure, formed on the metal surface. This characteristic motivated us to study electrochemical deposition of metal at the IL|W interface utilizing electron transfer across the interface. When we used AuCl4 - as the metal source dissolved in W and a reducing reagent dissolved in trioctylmethylammonium bis(nonafluorobutanesulfonyl)amide, which is a highly hydrophobic IL, spontaneous and simultaneous electron transfer-ion transfer reaction occurred and dendritic Au nanofibers were formed at the interface [5]. Similar dendritic nanofibers were formed at the IL|W interface of other highly hydrophobic ILs, although the fiber diameter depended on the ionic species of the ILs. On the other hand, when we used a conventional organic solvent, dichloromethane, instead of ILs, we obtained not nanofibers but micro-scale burr-like structures. In the present paper, the mechanism of the formation of such highly anisotropic nanostructure will be discussed and the application of this system to other nanostructures such as metal-polymer composites will be introduced. [1] T. Kakiuchi and N. Nishi, Electrochemistry, 74 (2006) 942-948. [2] Z. Samec, J. Langmaier, T. Kakiuchi, Pure Appl. Chem., 81 (2009) 1473-1488. [3] N. Nishi, Y. Yasui, T. Uruga, H. Tanida, T. Yamada, S. Nakayama, H. Matsuoka, T. Kakiuchi, J. Chem. Phys., 132 (2010) 164705(1-6). [4] N. Nishi, T. Uruga, H. Tanida, J. Electroanal. Chem., 759 (2015) 129-136. [5] N. Nishi, T. Kakinami, T. Sakka, Chem. Commun., 51 (2015) 13638-13641.

Synthesis of Gold Nanoparticles Capped with Quaterthiophene for Transistor and Resistor Memory Devices

Recently, the fabrication of nonvolatile memory devices based on gold nanoparticles has been intensively investigated. In this work, we report on the design and synthesis of new semiconducting quaterthiophene incorporating hexyl thiol group (4TT). Gold nanoparticles capped with4TT(4TTG) were prepared in a two-phase liquid-liquid system. These nanoparticles have diameters in the range 2–6 nm and are well dispersed in the poly(3-hexylthiophene) (P3HT) host matrix. The intermolecular interaction between4TTand P3HT could enhance the charge-transport between gold nanoparticles and P3HT. Transfer curve of transistor memory device made of4TTG/P3HT hybrid film exhibited significant current hysteresis, probably arising from the energy level barrier at4TTG/P3HT interface. Additionally, the polymer memory resistor structure with an active layer consisting of4TTGand P3HT displayed a remarkable electrical bistable behavior.

Test Reactions to Study Efficiency of

Abstract Effects of mixing on the course of fast chemical reactions are relatively well understood, especially in homogeneous systems. This enables to design and operate chemical reactors with the goal to achieve a high yield of a desired product and use systems of complex reactions as a chemical probe (chemical test reactions) to identify progress of mixing and quality of mixture. Recently, a number of studies have focused on the application of chemical test reactions to identify energy efficiency of mixing, being a convenient way of comparing mixers and reactors in terms of their mixing efficiency. This review offers a presentation of chemical test reactions available in the literature and methods of applications of test reactions to identify the energy efficiency of mixing. Also methods to assess the extent of micromixing by measuring product distribution or segregation index, and to determine the time constant for mixing are presented for single phase homogeneous systems and two-phase liquid-liquid systems.

Electrochemical Desulfurization of Dibenzothiophene Sulfone in Acetonitrile/Sodium Nitrate (aq)

Electrochemical techniques have attracted much attention in the last decade for oxidative and reductive desulfurization because they require less drastic conditions of temperature and pressure in comparison to other processes that are used for desulfurization. It is known that dibenzothiophene (DBT) can be oxidized progressively to dibenzothiophene sulfoxide (DBTO) and dibenzothiophene sulfone (DBTO2). However, it is interesting to know whether a more complete oxidation of DBTO2 is possible by electrochemical treatment in a liquid-liquid two-phase system.

Electrochemical Desulfurization of Dibenzothiophene Sulfone in Sodium Fluoride/Acetonitrile

The oxidative and reductive desulfurization using electrochemical techniques has attracted much attention in the last decade because mild temperature and conditions are needed [1, 2]. It is known that the dibenzothiophene (DBT) can be progressively oxidized to a sulfoxide dibenzothiophene (DBTO) and dibenzothiophene sulfone (DBTO2). However, the electrochemical oxidation and reduction DBTO2 in a liquid-liquid two-phase system of aqueous NaF/acetonitrile has not been reported. The analysis by Fourier Transformed Infrared Spectroscopy (FTIR) showed partial removal of sulfur from DBTO2 placed in the electrolytic medium at 18.6 ppm or 108 ppm. The FTIR spectrum of the samples diluted in KBr after cathodic electrolysis at -8.0 V on Pt or Ti as cathode and Pt as anode in an undivided cell showed the absence of the characteristic bands of DBTO2: 1288 cm-1, 1166 cm-1 and 758 cm-1. This suggests a transformation of DBTO2 with the electrochemical treatment (Fig. 1). The oxidation and reduction products of DBTO2 were analyzed by GC-MS and LC-MS. Figure 1 FTIR spectra of DBTO2 before electrochemical treatment (a) and after cathodic treatment using Pt electrode (b and c). IR spectra of the acetonitrile (b) and the aqueous (c) phases.

Modeling the hydrodynamics of slug flow in a minichannel for liquid-liquid two-phase system

The hydrodynamics of a Taylor flow in minichannels for a liquid-liquid system is modeled. As a result of solving an inverse problem, a relationship is derived for calculating the thickness of a film around the droplets of the dispersed phase from the velocity of the dispersed phase and the true volume fraction of the dispersed phase is calculated. The adequacy of the model is verified by experimental studies over a wide range of capillary numbers (Ca = 0.05–0.7).

Estimation of the catalytic activity of onium chlorides and bromides in the alkaline hydrolysis of amino acids esters

Relations were investigated between the structure of a series of onium salts, rates of alkaline hydrolysis catalyzed by the salts of 4-nitrophenyl N-benzyloxycarbonylglycinate in a two-phase liquid-liquid system, and the value of the standard exchange enthalpy of anions in ion pairs with the catalyst cation calculated by the semiempiric PM3 method. The catalytic activity of ammonium, phosphonium, pyridinium, imidazolium, and benzimidazolium salts in a wide range of cation structures varies in parallel with the enthalpy of formation of the active form of the catalyst by the exchange of the anion with a hydroxide ion.

Efficiency of phase-transfer catalysis in cyclopentene epoxidation with hydrogen peroxide

The effect of the structure and amount of the phase-transfer catalyst (quaternary ammonium salts) and the solvent effect on cyclopentene oxidation with an aqueous hydrogen peroxide solution in the liquid-liquid two-phase system was studied. The phase-transfer catalyst and solvent ensuring high reaction rate and high selectivity with respect to target products were chosen.

Magnetic properties of thiol-capped gold nanoparticles

We present the experimental results of magnetization measurements on thiol-capped gold nanoparticles (Au-SR NPs) synthesized in a two-phase liquid-liquid system. The size of particles ranged from 2.0 to 3.5 nm with an average size of 2.8 nm. The magnetic properties of Au-SR NPs were characterized by a mixture of ferromagnetic, paramagnetic and diamagnetic components. Magnetization curves showed the hysteresis behavior typical of a ferromagnet over the whole temperature (T) range investigated (2 K to 300 K) whereas M(H) did not saturate, not even at low T, implying the existence of a paramagnetic component. The negative slope of M(H) observed at high T demonstrated that a diamagnetic component was also considerable. From a theoretical fit, we obtained effective values of parameters such as the paramagnetic effective moment, μp = 5.7 μB, and the diamagnetic susceptibility, χd = −1.7 ×10−7 emu/gOe. In addition, the T-dependence of the ferromagnetic component Mf (T) was extracted from the experimental M(T), and its characteristics are discussed in the light of the mean field model.

The effects of the π–π stacking interactions on the patterns of gold nanoparticles formed at the air–water interface

Benzyl-n-hexadecyl dimethylammonium chloride (BHDC) monolayer-stabilized gold nanoparticles were synthesized in a two-phase liquid-liquid system and found to self-assemble into varied structures under the control of temperature at the air-water interface. It has been demonstrated that the π-π stacking interactions between the capping agent molecules significantly affect the formation of the unique patterns. A possible mechanism based on Marangoni-Bénard convection in the evaporating droplets and π-π stacking interactions was proposed. Four surfactants with similar structures: N-hexadecyl-N-methylpyrrolidinium bromide (C(16)MPB), 1-hexadecyl-3-methylimidazolium bromide (C(16)mimBr), 1-(2,4,6-trimethylphenyl)-3-hexadecylimidazolium bromide (C(16)pimBr) and hexadecyltrimethylammonium bromide (CTAB) were also used to further verify the formation mechanism mentioned above.

Online capillary liquid–liquid electroextraction of peptides as fast pre‐concentration prior to LC‐MS

In this research paper, we show that capillary electroextraction (cEE) is capable of fast online peptide concentration and that it can be coupled online to LC-MS to result in a fast and sensitive method. Electroextraction takes place when an electrical field is applied in a two-phase liquid-liquid system. Sample molecules in the organic phase migrate very fast into the aqueous phase and are concentrated in a small zone. In this work, cEE of peptides is developed and coupled online to LC-MS via a switching valve. Comparison of 10 min of cEE-LC-MS with a normal LC-MS injection showed more than 100-fold increased peak heights. Of five model peptides, good calibration curves in the range of 0.05-5 μmol/L were obtained. The linearity was good (R(2) values between 0.984 and 0.996) and RSD between 5% at the highest to 25% at the lowest concentration (n=3). The LOD of bradykinin, angiotensin I-converting enzyme inhibitor and angiotensin I was in the low nmol/L range. Analysis of a tryptic digest of eight model proteins resulted in more than 170 peptides, without bias for pI or hydrophilicity. Urine analysis is demonstrated, resulting in an LOD around 0.04 μmol/L urine for tryptic cytochrome C peptides spiked to urine and an increase of 42% in the number of chromatographic peaks compared with the conventional LC-MS. In summary, cEE-LC-MS is a fast electrophoresis-driven sample preconcentration technique that is quantitative, able to extract a wide peptide range and applicable to bioanalysis.

Patterns of Gold Nanoparticles Formed at the Air/Water Interface: Effects of Capping Agents

Gold nanoparticles stabilized with different capping agents were synthesized in a two-phase liquid-liquid system and found to self-assemble into various patterns at the air/water interface. The shapes of the patterns are closely related to the molecule structures of the capping agents. Systems with mixed capping agents were also investigated, and honeycomb patterns can be obtained in this way. T-shape and H-shape patterns were also observed. A possible mechanism based on Marangoni-Benard convection in evaporating droplets is proposed.

Chiral Ionic Liquid Monolayer-Stabilized Gold Nanoparticles: Synthesis, Self-Assembly, and Application to SERS

Chiral ionic liquid monolayer-stabilized gold nanoparticles were synthesized in a two-phase liquid-liquid system and found to self-assemble into ringlike structures at the air/water interface. Control experiments with long-chain ILs revealed that the molecular structure of the CIL significantly affects the formation of the gold nanoparticle ring structures. A possible mechanism based on Marangoni-Bénard convection in evaporating droplets was proposed. These gold nanoparticle structures were shown to yield a large SERS enhancement for Rhodamine 6G.