Facilitated Pertraction of p-Aminobenzoic Acid with Amberlite LA-2 in Presence of 1-Octanol

p-Aminobenzoic acid has been facilitated pertracted with Amberlite LA-2 dissolved in dichloromethane, using a U-shaped pertraction cell which allows obtaining the free liquid membrane. The pertraction has been a carrier out in the presence of 1-octanol added in the liquid membrane. The addition of the alcohol led to the increase for up to 3 times of the acid initial and final mass flows, this effect being directly related to the process variables (pH-gradient between the aqueous phases, carrier and alcohol concentrations inside the membrane phase, mixing intensity). But, the influence of 1-octanol on the transport capacity of the pertraction system was negative, its addition inducing the accumulation of PABA in the liquid membrane, and requiring the reevaluation and optimization of the acid reextraction from the membrane phase to the stripping one.     

Separation of rosmarinic acid by facilitated pertraction

Rosmarinic acid has been separated by facilitated pertraction with D2EHPA dissolved in dichloromethane. The pertraction has been carried out in presence of 1-octanol, added into the liquid membrane. The addition of the alcohol led to the increase for more than twice the rosmarinic acid initial and final mass flows, this effect being directly related to the process variables (pH-gradient between the aqueous phases, carrier and alcohol concentrations inside the membrane phase, mixing intensity). But, the influence of 1-octanol on the transport capacity of the pertraction system was negative, its addition inducing the accumulation of rosmarinic into the liquid membrane. Due to this effect, the reevaluation and optimization of the reextraction process from the membrane phase to the stripping are required.     

Selective Separation of Cinnamic and p‐Methoxycinnamic Acids by Facilitated Pertraction

Abstract

Cinnamic acid can be selectively separated from p‐methoxycinnamic acid by facilitated pertraction with Amberlite LA‐2 dissolved in dichloromethane, using a U‐shaped pertraction cell which allows obtaining the free liquid membrane. The pertraction has been analyzed by means of initial and final mass flows, permeability and selectivity factors. The main factors which control the pertraction selectivity were identified to be the pH‐gradient between the feed and stripping phase and the mixing intensity of the aqueous phases. The maximum selectivity factor has been recorded for pH=2 of feed phase, pH=8 of stripping phase, rotation speed lower than 300 rpm, and carrier concentration higher than 40 g/l.     

Study on Facilitated Pertraction of Folic Acid in Pseudosteady-State Regime

The influences of the pH-gradient between the feed and stripping phases and of carrier concentration inside the membrane phase on the efficiency of facilitated pertraction of folic acid with Amberlite LA-2 in pseudosteady-state mode have been analyzed. The experiments have been carried out using a U-shaped pertraction cell which allowed to easily maintaining the liquid membrane between the two aqueous phases. On the basis of the experimental data and theoretical investigation on pseudosteady-state regime, two models describing the acid accumulation inside the liquid membrane by means of the permeability factor have been developed for two pH-values of feed phases (5.2 and 3, respectively). The proposed models offer good concordance with the experimental data and can be useful for facilitated pertraction optimization.     

Kinetics of the liquid phase dehydration of 1‐octanol to di‐n‐octyl ether on Amberlyst 70

The kinetics of the liquid phase dehydration of 1‐octanol to di‐n‐octyl ether (DNOE) over Amberlyst 70 was studied at 413–453 K. Mechanistic rate models assuming water and 1‐octanol adsorbed on the resin, and the free sites fraction negligible, were selected from 1‐octanol dehydration experiments. Next, the influence of DNOE, water, and 1,4‐dioxane (solvent) concentration was evaluated. DNOE and 1,4‐dioxane do not affect significantly the reaction rate, while water inhibits it strongly. Water effect was quantified by splitting the rate constant into a “true one” and a correction factor related to the fraction of active sites blocked by water. The best kinetic model stemmed from an Eley‐Rideal mechanism with water adsorbed onto the resin and DNOE released directly to the liquid phase, with a correction factor for water inhibitory effect based on a Freundlich isotherm‐like function; activation energy being 110 ± 5 kJ·mol^?1, in line with literature data on homologous reactions. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3966–3978, 2017     

Influence of Solvent Polarity on the Mechanism and Efficiency of Formic Acid Reactive Extraction with Tri‐n‐Octylamine from Aqueous Solutions

The reactive extractions of formic acid with tri‐n‐octylamine (TOA) dissolved in three solvents with different dielectric constants (dichloromethane, butyl acetate, n‐heptane) without and with 1‐octanol as phase modifier were comparatively analyzed. The results indicated that the mechanism of the interfacial reaction between acid and extractant (Q) is controlled by the organic phase polarity. In the absence of 1‐octanol, the structures of the extracted complexes are (HA)₂Q₂ for dichloromethane and butyl acetate, and (HA)₂Q₄ for n‐heptane. These structures are modified by adding 1‐octanol and become (HA)₂Q for extraction in dichloromethane or butyl acetate, and (HA)₂Q₂ for extraction in n‐heptane. Although the presence of 1‐octanol improves the extraction efficiency, it leads to a reduction of the extraction constants for all considered solvents, an influence that is more significant for n‐heptane.     

Silver Recovery from Dilute Aqueous Solutions Using Semi‐Batch RF‐Pertraction

Silver recovery from dilute nitrate solution was studied by using a rotating film‐pertraction technique in a semi‐continuous mode. Tri‐isobutylphosphine sulphide (TIBPS) dissolved in kerosene was used as a carrier and an aqueous ammonia solution as a stripping phase. A high transfer flux of silver ions during the pertraction process was observed. It was shown that the selectivity of silver transport through the TIBPS‐containing liquid membrane provides an excellent separation of silver from other metals such as copper, nickel, and iron presented in the treated solutions.     

Direct Extraction of Propionic Acid from Propionibacterium acidipropionici Broths with Tri‐n‐octylamine

The direct reactive extraction of propionic acid from Propionibacterium acidipropionici broths with solutions of tri‐n‐octylamine in dichloromethane, n‐butyl acetate or n‐heptane underlined the strong negative influence of the cells, due to the blockage of the interface by their adsorption. The magnitude of this effect <#>depends on the affinity of the cells for the organic phase, which is more important for n‐heptane, but only at biomass concentrations below 18 g L^–1 d.w. (dry weight). Moreover, the interfacial mass transfer of the acid is also controlled by the solvent polarity, and is accelerated from n‐heptane to dichloromethane and by the addition to the organic phase of 1‐octanol as a phase modifier. The influences of the biomass concentration, the rotation speed and the solvent dielectric constant were included in a mathematical model describing the solute mass flow from the aqueous to the organic phase.     

Characterisation of the mixture product of ether‐soluble fraction of bio‐oil (ES) and bio‐diesel

A method of upgrading the properties of bio‐oil with bio‐diesel has been taken in this article. Firstly, the unpopular pyrolytic lignin fraction is extracted from bio‐oil using ether, the rest ether‐soluble fraction of bio‐oil, named ES is mixed with bio‐diesel according to emulsification. The optimal conditions for obtaining a stable ES/bio‐diesel mixture are with octanol surfactant dosage of 3% by volume; initial ES to bio‐diesel ratio of 4:6 by volume; stirring intensity of 1200 rpm; mixing time of 15 min and mixing temperature at 30°C. Additionally, selected fuel properties such as viscosity, water content and acid number are measured for characterising the ES/bio‐diesel mixture. Thermogravimetric analysis (TGA) has been used to further evaluate the thermal properties. Data from the TGA and Fourier transform infrared spectroscopy (FTIR) analyses confirm the presence or absence of certain group of chemical compounds in the mixture. Proton and carbon atoms assignments are further confirmed by ¹H NMR (nuclear magnetic resonance) and ¹³C NMR analysis, respectively. © 2011 Canadian Society for Chemical Engineering     

Photo‐crosslinking of poly[ethene‐stat‐(methacrylic acid)] functionalised with maleimide side groups

BACKGROUND: Photo‐crosslinkable polymers are well known and commercially applied as photoresists. But so far they have not been applied as membrane materials for separation processes. They would offer certain advantages in membrane fabrication over conventional crosslinked polymer materials. Therefore, in this work, a poly[ethene‐stat‐(methacrylic acid)] (PEMAA) which is a potential membrane polymer for different separation problems was functionalised with photo‐crosslinkable maleimide side groups. RESULTS: It has been shown that PEMAA can be used as basic polymer material and a conversion with 3‐hydroxypropylmaleimide is possible in order to obtain a photo‐crosslinkable polymer. Investigation of the crosslinking mechanism was performed using stationary infrared and UV‐visible spectroscopy as well as nanosecond transient spectroscopy absorption measurements of a rotating film. Intense transient absorption of the maleimide‐esterified PEMAA occurs at 250 nm in the film pointing to maleimide anion formation and crosslinking via an ionic dimerisation mechanism. CONCLUSION: It is found that crosslinking reactions can be observed spectroscopically in situ using a maleimide‐functionalised PEMAA. Furthermore, experiments can be performed in the liquid phase (polymer in solution) as well as in the solid phase (polymer film) using a rotating polymer film sample. Maleimide anion formation and crosslinking via an ionic dimerisation mechanism can be investigated by variation of the polymer structure as well as the structure of the maleimide side groups. Copyright © 2009 Society of Chemical Industry     

Cobalt removal from waste‐water by means of supported liquid membranes

BACKGROUND: Supported liquid membranes (SLM) are an alternative technique to remove and recover metals from diluted process solutions and waste‐water. In the present work, the removal of Co(II) from a synthetic CoSO₄ solution containing initial amounts of cobalt(II) in the range 100–200 ppm (0.1–0.2 g dm^?3) has been studied on a pilot scale. By performing batch equilibrium experiments, the optimal settings, i.e. the composition of the organic phase, the pH of the feed, the type and concentration of the stripping agent were determined. RESULTS: It is shown that the equilibrium characteristics of a synergistic extractant mixture containing di‐2‐ethyl‐hexylphosphoric acid (D2EHPA) and 5‐dodecylsalicylaldoxime (LIX 860‐I) are superior to D2EHPA. Both hydrochloric acid and sulfuric acid have been evaluated as stripping solutions in liquid–liquid extraction tests and as the receiving phase in a SLM configuration. Although equilibrium tests showed no difference in stripping characteristics between both chemicals, it was observed that in a SLM configuration the stability of the system when hydrochloric acid is used is poor. With a commercially available SLM module (Liqui‐Cel Extra‐Flow 4 × 28) having a surface area of 19 m², a steady Co(II) flux of 0.140 gm^?2h^?1 has been obtained at influent concentrations of cobalt between 100 and 200 ppm with 3 mol dm^?3 sulfuric acid as stripping phase. CONCLUSIONS: The results obtained show that a supported liquid membrane containing a synergistic mixture of LIX 860‐I and D2EHPA gives the possibility of recovering cobalt from dilute solutions. Copyright © 2008 Society of Chemical Industry     

Synthesis and application of an alternative plasticizer Di(2‐Ethylhexyl)‐1,2‐cyclohexane dicarboxylate

Cyclohexane dicarboxylic acid esters are environmentally friendly and non‐toxic plasticizers, and have similar performance with phthalates which have potential toxicity to human health. In this article, di(2‐ethylhexyl)‐1,2‐cyclohexane dicarboxylate (DEHCH) was synthesized via esterification between hexahydrophthalic anhydride (HHPA) with iso‐octanol by using concentrated sulfuric acid as a catalyst. The effects of reaction parameters on esterification were studied by investigating the temperature, reaction time, molar ratio of iso‐octanol‐to‐HHPA, and catalyst content. Conversions of HHPA to esters were determined. Functional group analysis was conducted by using FTIR and ¹H‐NMR spectroscopy. PVC compounds after addition of the synthesized plasticizer DEHCH presented similar plasticizing performance with DEHP and DINCH, as demonstrated by comparisons of the results of mechanical properties, transparency, and volatilization and migration tests obtained for plasticized PVC compounds. DEHCH can also be considered as an alternative plasticizer for DEHP. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39763.     

Structural effects of ion‐exchange membrane on the separation of L‐phenylalanine (L‐Phe) from fermentation broth using electrodialysis

The effects of membrane structure on the separation of L ‐phenylalanine (L ‐Phe) by electrodialysis from a fermentation broth and on the fouling tendency were investigated in this study. Two anion‐exchange membranes (Neosepta AFX and AM‐1, Tokuyama, Japan) were selected and characterized using the chronopotentiometry method. For a fresh membrane, AFX showed a lower electrical resistance and a lower permselectivity than AM‐1. After being fouled with humic acid, however, the electrical resistance of AFX was higher than that of AM‐1. The L ‐Phe selectivities for both membranes were lower than those of the fresh membranes. The result may be attributed to the structural difference between AFX and AM‐1 membranes. AFX has a lower repulsion force against the co‐ion and could be more strongly affected by the foulants than AM‐1 because AFX has a more porous structure than AM‐1. Experiments on the separation of L ‐Phe from the fermentation broth were carried out using two different stack configurations, ie desalting electrodialysis and water‐splitting electrodialysis. It was observed that the recovery efficiency of L ‐Phe through electrodialysis for 100 min reached 95% for AFX and 85% for AM‐1. In the desalting configuration of electrodialysis, the solution pH must be adjusted to alkaline conditions to recover the L ‐Phe through the anion‐exchange membrane. On the contrary, it was possible to recover the L ‐Phe without adjustment of the solution pH in the water‐splitting electrodialysis because OH^? generated from the bipolar membrane converted neutral L ‐Phe into an anion. © 2002 Society of Chemical Industry     

Extraction properties of phthalic acid and aromatic polycarboxylic acids using various solvents

BACKGROUND: To explore the extraction properties of aromatic acids produced in the oxidation of coal, the extraction equilibrium of phthalic acid (as a typical product) was studied using three solvents, 1‐octanol, 50% tributylphosphate (TBP)/kerosene, and 10% trialkylphosphine oxide (TRPO)/kerosene, and the feasibility of separating phthalic, [1,1′‐biphenyl]‐2,2′‐dicarboxylic and trimellitic acids is discussed. RESULTS: Phthalic acid extraction followed the sequence: 10% TRPO > 50% TBP > 1‐octanol, with recoveries from the TRPO and TBP systems being much larger than that for 1‐octanol. The stoichiometry of formation of the complexes of TBP and TRPO with phthalic acid was 1:1. The apparent extraction equilibrium constant for TRPO is much larger than that for TBP. The distribution coefficient of [1,1′‐biphenyl]‐2,2′‐dicarboxylic acid is much larger than that of the other two acids using 1‐octanol as the extractant and this acid could be removed by 1‐octanol from a mixture of the three acids. The extraction equilibrium correlations obtained for the individual acid component systems can be used to predict that of the acid mixture. CONCLUSION: The extent of phthalic acid extraction by the three solvents investigated is as follows: 10% TRPO > 50% TBP > 1‐octanol. The stoichiometry of the complex formation of TBP or TRPO and phthalic acid is 1:1, and the apparent extraction equilibrium constant for TRPO is much larger than that for TBP. 1‐octanol shows a good extractive selectivity for [1,1′‐biphenyl]‐2,2′‐dicarboxylic acid as compared with phthalic and trimellitic acids. Copyright © 2011 Society of Chemical Industry     

Synthesis and characterization of chiral side‐chain liquid‐crystalline polymer containing menthol ester

The synthesis of new chiral side‐chain liquid‐crystalline polysiloxanes containing p‐(allyoxy)benzoxy‐p‐chlorophenyl (ABCH) as mesogenic units and undecylenic acid menthol ester (UM) as chiral nonmesogenic units is presented. The chemical structures of monomers and polymers are confirmed by IR spectroscopy. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) are used to measure thermal properties of those polymers. Mesogenic properties are characterized by polarized optical microscope (POM), DSC, and small‐angle X‐ray diffraction. Analytic results revealed that polymers P₀–P₆ are thermotropic liquid‐crystalline polymers with low glass transition; Polymers P₂–P₆ exhibit chiral smectic liquid‐crystalline properties with marble texture, optical rotation, and a sharp reflection at low angles in X‐ray diffraction; polymers P₀, P₁ only exhibit smectic liquid‐crystalline properties without chirality; and P₇ only exhibits chirality without liquid‐crystalline properties. All the polymers exhibit good thermal stability with temperature of 5% mass loss over 297°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2845–2851, 2003     

Pertraction of cations in a hybrid membrane system containing soluble polymeric ionophores

A hybrid membrane system composed of two insoluble cation‐exchange membranes (Nafion) and a liquid membrane in between was studied. A series of organic and aqueous liquid membranes containing soluble polymers as macromolecular ionophores (macroionophores) was prepared and tested. The pertraction (membrane‐transport) characteristics of poly(ethylene glycol) and its ionizable derivatives, including as poly[poly(oxyethylene) phosphate] (PPOEP) and di‐[ω‐methoxy poly(oxyethylene)] phosphate, were measured and are discussed as dependent on the composition and molecular mass of a macroionophore. The liquid membrane composed of PPOEPs dissolved in dichloroethane combined the cation‐exchange properties with neutral coordination functionalities introduced by the poly(oxyethylene) backbone of this ionophore. The overall fluxes, facilitation factors, and the membrane system selectivity were measured in the carrier‐mediated pertraction of transient metal cations (Cu²⁺, Zn²⁺, Mn²⁺, Co²⁺, and Ni²⁺). PPOEP could facilitate the pertraction of Zn²⁺ and Cu²⁺ over Ni²⁺ and Co²⁺. In the case of an aquatic hybrid membrane system, high but nonselective ionic fluxes were observed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 99–109, 2002; DOI 10.1002/app.10263     

A Novel Assembly of Substituted Pyrroles by Acid‐Catalyzed Sequential Three‐Component Reaction of Amines,Alkynoates, and 1,2‐Diaza‐1,3‐dienes

A novel protocol for the assembly of polysubstituted pyrroles has been developed through the acid‐catalyzed, sequential three‐component reaction of primary aliphatic amines, alkynoates and 1,2‐diaza‐1,3‐dienes (DDs). This methodology proceeds with complete chemo‐/regioselectivity involving first formation of an enamino ester intermediate, in situ Michael addition with azo‐ene compounds and subsequent intramolecular ring closure.     

COSMO‐RS Calculations of Partition Coefficients: Different Tools for Conformation Search

This work is encouraged by the growing interest and recent success of quantum mechanics‐based methods in modeling of thermodynamic properties in the field of chemical engineering and life sciences. Among those, the COSMO‐RS model has become one of the most popular methods to predict phase equilibria in complex bio‐related systems. Recently, we have shown that the quality of predictions of n‐octanol/water and micelle/water partition coefficients is improved when the weighted mixtures of conformers are used to represent molecules, thereby demanding that the conformation analysis is performed for each component of the system. In this paper, different methods for performing the conformational search are evaluated. Micelle/water partition coefficients of solutes from different homologous series in aqueous solutions of Triton X100 as well as the n‐octanol/water partitioning of three common drugs (aminopinicillanic acid, ampicillin, and penicillin G) are calculated and compared with experimental data. Conformational analysis is made by the HyperChem program for the molecules placed in vacuum as well as by using the molecular dynamics simulation in a solvent medium (n‐octanol and water). It is demonstrated that molecular dynamics simulation is a promising tool to conduct conformational analysis. Along with the possibility of providing the conformers for large surfactant and pharmaceutical molecules, the method accounts for the solvent in a realistic manner. The results for micelle/water partition coefficients illustrate that n‐octanol is a reasonable approximation for the “micelle‐like” medium in molecular dynamics (MD) simulations. Predicted n‐octanol/water partition coefficients of three penicillins are in a good agreement with literature data and values calculated by a common quantitative structure‐activity relationship (QSAR).     

Bifunctional poly(ethylene glycol) based crosslinked network polymers as electrolytes for all‐solid‐state lithium ion batteries

Polymer electrolyte based lithium ion batteries represent a revolution in the battery community due to their intrinsic enhanced safety, and as a result polymer electrolytes have been proposed as a replacement for conventional liquid electrolytes. Herein, the preparation of a family of crosslinked network polymers as electrolytes via the ‘click‐chemistry’ technique involving thiol‐ene or thiol‐epoxy is reported. These network polymer electrolytes comprise bifunctional poly(ethylene glycol) as the lithium ion solvating polymer, pentaerythritol tetrakis (3‐mercaptopropionate) as the crosslinker and lithium bis(trifluoromethane)sulfonimide as the lithium salt. The crosslinked network polymer electrolytes obtained show low T_g, high ionic conductivity and a good lithium ion transference number (ca 0.56). In addition, the membrane demonstrated sterling mechanical robustness and high thermal stability. The advantages of the network polymer electrolytes in this study are their harmonious characteristics as solid electrolytes and the potential adaptability to improve performance by combining with inorganic fillers, ionic liquids or other materials. In addition, the simple formation of the network structures without high temperatures or light irradiation has enabled the practical large‐area fabrication and in situ fabrication on cathode electrodes. As a preliminary study, the prepared crosslinked network polymer materials were used as solid electrolytes in the elaboration of all‐solid‐state lithium metal battery prototypes with moderate charge–discharge profiles at different current densities leaving a good platform for further improvement. © 2018 Society of Chemical Industry     

Sulfur dioxide non‐dispersive absorption in N,N‐dimethylaniline using a ceramic membrane contactor

BACKGROUND: Removal of sulfur dioxide from gas emissions by selective absorption is a common method to separate and concentrate sulfur dioxide and to reduce air pollution and environmental risks. N,N‐dimethylaniline is an organic solvent used in some industrial applications for its sulfur dioxide affinity, leading to a regenerative process. However, the use of scrubbers and equipment in which direct contact between gas and liquid takes place leads to solvent losses due to evaporation and drops dragging. RESULTS: In this work, an innovative procedure based on non‐dispersive absorption in a ceramic hollow fibre membrane contactor was studied in order to avoid drops dragging. The absorption efficiency ranged between 40 and 50%, showing the technical viability of the process. The sulfur dioxide flux through the membrane has a linear relationship with the concentration of SO₂ in the gas stream and an overall mass transfer coefficient K_overall = (1.10 ± 0.11) × 10^?5 m s^?1 has been obtained. CONCLUSIONS: The mass transfer behaviour of a ceramic hollow fibre membrane contactor for sulfur dioxide non‐dispersive absorption in N,N‐dimethylaniline has been studied. The main resistance is found to be the ceramic membrane and the effective diffusivity has been inferred. The mass transfer model and parameters allow the evaluation of equipment design for technical applications. Copyright © 2008 Society of Chemical Industry