Water In Organic Phase Research Articles

Support-free interfacial polymerized polyamide membrane on a macroporous substrate to reduce internal concentration polarization and increase water flux in forward osmosis

Macroporous substrates have great potential in the development of high performance thin film composite forward osmosis (TFC FO) membranes. This paper reports on the preparation of TFC FO membrane via support-free interfacial polymerization (SFIP) technology on a macroporous substrate. SFIP technology can effectively break the bottleneck of conventional interfacial polymerization (IP) technology, which makes it difficult to form a complete polyamide (PA) film on the macroporous substrate. Briefly, the complete PA film is formed at the free water-organic phase interface and then attached to the macroporous substrate by vacuum filtration. The monomer concentration and filtration pressure were adjusted to form the optimal SFIP-PA film. Meanwhile, we chose a macroporous polyvinylidene fluoride (PVDF) microfiltration substrate and screened the pore size to reduce the structural parameters and then the internal concentration polarization, which caused the improvement of water flux. The performance of SFIP-PVDF membranes was investigated and discussed. Under the AL-FS mode with DI water and 1.0 M NaCl solution as the feed solution and draw solution, respectively, the SFIP-PVDF membrane, which used a macroporous PVDF substrate with a pore size of 0.45 μm exhibited a water flux (20 L/m2·h) and a reverse salt flux (2.5 g/m2·h). Besides, the membrane showed good stability in the 72 h test. The specific salt flux (Js/Jw) of SFIP-PVDF membranes was much lower than that of IP-PVDF membranes prepared via IP technology, which were incomplete and defective, suggesting that SFIP technology was superior to IP technology. This work effectively exploits the potential of macroporous substrates for the development of high performance TFC FO membranes and provides an insight into the high performance FO membrane design.

Разработка метода прямого экстракционно-спектрофотометрического определения молибдат-ионов в системе антипирин – сульфосалициловая кислота – вода

The stratified system antipyrine - sulfosalicylic acid - water eliminates the use of toxic organic solvents, allows for the group extraction of macro- and micro-quantities of elements into a small volume (~ 2 ml) water-organic phase, in this phase many photometric reagents are easily dissolved. The extraction-spectrophotometric method for the determination of molybdate-ions with phenylfluorone has been developed. The optimal conditions for the formation of a colored compound with an organic reagent have been determined: light absorption maximums; optimal time for color development; photometric reagent amount, linearity range of the calibration graph. In optimal conditions for the complexation of phenylfluorone with MoO42- (λ = 526 nm, τ = 20 min, CR = 5·10-5 mol/l), a calibration graph is constructed. The Bouguer-Lambert-Beer’s law is fulfilled in the range from 10 to 60 μg Mo(VI)/20 ml. The molar coefficient of light absorption is calculated, which is 9.2∙104. The effect of interfering ions on the direct extraction-spectrophotometric determination of molybdate ions is studied. It is found that the determination of 50.0 μg of molybdenum(VI) does not interfere with: 5000 - fold molar excess of Ni(II), Co(II), Cr(III), Mn(II), Cd(II), Zn(II), Pb(II); 500 - fold molar excess of Re(VII); 1 - fold molar excess of In(III), W(VI).

Accurate modeling of multiphase behavior of aqueous systems. I. Alkanes, alkenes, cycloalkanes, alcohols, aromatics

This work presents an approach to accurately modeling the mutual solubilities and multiphase behavior of aqueous systems. For this purpose, a new PC-SAFT parameters set for water was proposed and temperature-dependent binary interaction parameters, kij(T) were determined by fitting to the mutual solubilities data of water/n-hexane and water/benzene mixtures. These kij(T) have been used to predict the mutual solubility and multiphase equilibria of similar mixtures for an extended temperature range up to 473 K. Very good agreement between predicted results and available experimental data has been obtained, including the description of the minimum of hydrocarbon solubility in water as a function of temperature. The model's overall average relative deviations from experimental data were 19.9% and 18.1% for the solubility of water in organic phase and of hydrocarbons in aqueous phase, respectively.To test the model's capabilities, the parameters were used to predict multiphase behavior for water-alcohol-hydrocarbon ternary systems and gave good results compared with experimental data.

PENGARUH PERBANDINGAN VOLUME FASA AIRDENGAN FASA ORGANIK DAN KONSENTRASI AgDALAMFASA AIR PADA EKSTRAKSI PERAKDARI LIMBAH FOTO ROENTGEN

Roentgen photo waste containing silver metal ion (Ag+) in form of silver thiosulfic complex ([Ag(S2O3)2]3-) that danger for health and environment. To prevent contamination to environment by silver metal from roentgen photo waste, separation become need to do. Solvent extraction was one of available separation technique on this case. The aim of this research was to evaluate the influence of few extraction parameters that was water-organic phase ratio and Ag concentration on water phase to silver extraction percentage, and apply optimum condition to roentgen photo waste sample. Silver extraction was applied on various water-organic phase ratios, there were 5 : 10; 10 : 10; 25 : 10; 50 : 10; and 75 : 10 mL and various silver concentration on water phase, there were 10, 20, 30, and 40 ppm. Ag+ ion concentration was measured by AAS in 328.22 nm wavelength before and after extraction process, than calculation of silver extraction percentage could be conducted. Based on research result, optimum condition of silver extraction was obtained on 1 : 2 of water-organic phase ratio and 10 ppm of Ag concentration on water phase. 10,27 % silver extraction was obtained on application of optimum extraction condition on roentgen photo waste.

α,α′,α″,α′″-meso-tetrahexyltetramethyl-calix[4]pyrrole: an easy-to-prepare, isomerically pure anion extractant with enhanced solubility in organic solvents

α,α′,α″,α′″-meso-Tetrahexyltetramethyl-calix[4]pyrrole is easily obtained as a single diastereomer in a one-pot reaction. It exhibits enhanced solubility in organic solvents, including aliphatic solvents, relative to its parent meso-octamethylcalix[4]pyrrole (1). Somewhat surprisingly, the tetrahexyl derivative 2 complexes with tributylmethylammonium chloride in chloroform more strongly than does 1 as shown by NMR titrations. However, 1 and 2 exhibit comparable complexation strength in extraction experiments, the difference between the NMR and extraction results being attributed to the effect of organic-phase water in the extraction systems. Mass-action analysis indicates the formation of the predominant complex TBMA+(1 or 2)Cl− in both NMR and extraction systems, and equilibrium constants are reported. x-Ray crystal structures were obtained for the free ligand 2 and its complex with tetramethylammonium chloride. The free ligand crystallises in the 1,3-alt conformation with equatorial hexyl arms. In the chloride complex with 2 in its cone conformation, the hexyl arms adopt an axial orientation, enveloping the anion. DFT calculations show this binding conformation to be the most stable, mostly owing to destabilising steric interactions involving the pyrrole C–H and alkyl C–H groups positioned equatorially.

Water uptake by organic aerosol and its influence on gas/particle partitioning of secondary organic aerosol in the United States

Abstract Organic aerosol (OA) is at least partly hygroscopic, i.e., water partitions into the organic phase to a degree determined by the relative humidity (RH), the organic chemical composition, and the particle size. This organic-phase water increases the aerosol mass and provides a larger absorbing matrix while decreasing its mean molecular weight, which can encourage additional condensation of semi-volatile organic compounds. Most regional and global atmospheric models account for water uptake by inorganic salts but do not explicitly account for organic-phase water and its subsequent impact on gas/particle partitioning of semi-volatile OA. In this work, we incorporated the organic-phase water model described by Pankow et al. (2015) into the UCD/CIT air quality model to simulate water uptake by OA and assessed its influence on total OA mass concentrations. The model was run for one summer month over two distinct regions: South Coast Air Basin (SoCAB) surrounding Los Angeles, California and the eastern United States (US). In SoCAB where the OA was dominated by non-hygroscopic primary OA (POA), there was very little organic-phase water uptake (0.1–0.2 μg m−3) and consequently very little enhancement (or growth) in total OA concentrations (OA + organic-phase water): a 3% increase in total OA mass was predicted for a 0.1 increase in relative humidity. In contrast, in the eastern US where secondary OA (SOA) from biogenic sources dominated the OA, substantial organic-phase water uptake and enhancement in total OA concentrations was predicted, even in urban locations. On average, the model predicted a 20% growth in total OA mass for a 0.1 increase in relative humidity; the growth was equivalent to a 250 nm particle with a hygroscopicity parameter (κ) of 0.15. Further, for the same relative humidity, the exact extent of organic-phase water uptake and total OA enhancement was found to be dependent on the particle mixing state. When the source-oriented mixing state of aerosols was considered, generally, less organic-phase water uptake was predicted than when simple internal mixing approximations were made. Overall, the results indicated that organic-phase water can significantly influence predicted total OA concentrations under certain conditions. Regional models applied in areas with high humidity and significant SOA formation should include calculations for organic-phase water in order to capture this effect.

Response to comment of Sierra Rayne on “Targeting aquatic microcontaminants for monitoring: exposure categorization and application to the Swiss situation [Götz et al., Environ Sci Pollut Res (2010) 17:341–354

In the comment of S. Rayne on the article “Targeting aquatic microcontaminants for monitoring,” two concerns are raised: (1) The article lacked pKa data. The author of the comment claims that the pKa values are missing for 26 of the approximately 250 substances investigated. (2) The model that was applied for the calculation of water–organic phase partitioning is too simplistic to correctly describe sorption to solid phases. Essentially, both questions target the applicability of the presented method for assessing the aquatic fate of ionizable substances. The method presented clearly has its shortcomings with respect to these substances. However, since the method presented in our article was intended as a screening tool to select substances for monitoring, it was developed to cover the broadest range of chemicals possible, and therefore false positive and negative answers have to be accepted to a certain extent, as in every screening tool. The main objective was to develop an easily applicable method that had a lower data demand than other existing models and allowed the identification of new substances that might warrant more intense investigation. Response to query 1: “lack of pKa data”

ChemInform Abstract: Multiphase Homogeneous Catalysis: Common Procedures and Recent Applications

AbstractReview: about 100 refs.

Role of Trace Amounts of Water in Transfers of Hydrophilic and Hydrophobic Ions to Low-Polarity Organic Solvents

The effect of water content in a low polarity organic phase on transfers of hydrophobic and hydrophilic ions across the liquid/liquid interface was investigated by nanopipet voltammetry. It was shown recently (J. Am. Chem. Soc. 2006, 128, 15019) that hydrophilic ions can be transferred to less polar solvents such as 1,2-dichloroethane (DCE) only in the presence of organic counterions that facilitate such processes. The addition of trace amounts of water to neat DCE induces the transfers of hydrophilic ions but practically does not affect the transfers of hydrophobic species. Although the conductivity of neat DCE decreases upon addition of water to it, the rates of hydrophilic ion transfers increase markedly with increasing concentration of water in organic phase. This observation suggests different transfer mechanisms for hydrophobic and hydrophilic ions: while the former are transferred directly into neat organic solvents, the latter can only be transferred to aqueous clusters dispersed in organic phase.

Self-assembly of water-dispersed gold nanoparticles stabilized by a thiolated glycol derivative

Two-dimensional (2D) hexagonally close-packed arrays of water-dispersed gold nanoparticles (NPs) on highly hydrophilic sputter-deposited SiO2 surfaces were fabricated via an evaporation-induced self-assembly process. Using a non-ionic amphiphilic glycol derivative with the thiol head group, 1-mercapto-3,6,9-trioxodecane, as a stabilization ligand, high-concentration Au NPs were stably dispersed in water, and self-assembled into μm-sized well-ordered 2D arrays on SiO2 surfaces during the solvent evaporation on SiO2 surfaces. Due to the non-ionic character of the ligand, the particle–particle interactions may only depend on the capillary and van der Waals forces, and not on the electric double-layer forces that change with ion/electrolyte concentrations during the solvent evaporation. This study provides an approach to fabrication of close-packed 2D arrays of water-dispersed NPs instead of using toxicological organic solvent or complex water-organic phase transfer process. Meanwhile, this approach will make it easier to study their self-assembly mechanisms in a variety of solvents by simplifying ambiguous particle–particle interactions.

Modelling of the enzymatic synthesis of taste dipeptides with simultaneous extraction in a membrane phase contactor

The paper presents a model of the synthesis process of taste dipeptides carried out in a biphase water-organic phase system. An enzymatic conversion takes place within the aqueous phase where the enzyme is dissolved. The catalysis process is accompanied by the transport of reagents from/to the organic phase, which is a reservoir of hydrophobic reagents. The membrane contactor with a porous membrane holds the interface surface that serves as an interface area to the reactant mass transfer. The model was verified on the basis of the synthesis reaction of ZAlaPheOMe, a precursor of bitter dipeptide. The process was carried out in the ethyl acetate-polypropylene membrane-0.05 M Tris-HCl buffer system. Good agreement of experimental and model results was presented that enabled computer simulations of the process. That allowed us to choose the optimum parameters used in the batch and continuous process. The influence of interface surface area, phases volume and reagent concentrations on the process course, productivity and product purity was shown.

Extraction of compactin (ML-236B): equilibrium distribution in water–ethyl acetate system

Equilibrium partitioning of compactin in water–ethyl acetate system was measured at 298 K. The extraction pH showed strong influence on the partitioning ratio: the partitioning ratio decreased with pH. The dissociation constant and distribution coefficients of compactin were determined by treating equilibrium data with numerical approach. Distribution coefficient of compactin in water–ethyl acetate system was treated as a variable and a function of compactin concentration in aqueous solution. The estimated values of dissociation constant and distribution coefficient were compared with the values of water–toluene system. The mutual solubility of ethyl acetate and water was also measured at the same temperature when compactin concentration was varied. The investigation found that increasing compactin concentration increased mutual solubility of water in organic phase as well as of ethyl acetate in aqueous phase. The increasing mutual solubility caused the change of solute composition in aqueous solution and affect equilibrium distribution of compactin.

Non-Covalent Adducts of Sodium Poly(α,L-glutamate) with Poly(N-vinyl pyrrolidone): Methods of Preparation and Characterization of Structure

Non-covalent adducts of poly(N-vinyl pyrrolidone) (PVP) (mol. wt. 10 K & 29 K) with sodium poly(α,L-glutamate)(PGNA) (mol. wt. 32 K) are prepared by evaporation of aqueous mixtures (EAM), ultra-centrifugation (UC) and dehydration of reverse micelles (DRM). The EAM and UC adducts contain nearly equal amounts of PVP while the DRM adduct has lower amounts. Higher-molecular-weight PVP favored greater PVP content in the adducts regardless of the method of preparation. DSC thermograms, and FT-IR and CD spectra of the three adducts in the solid state revealed that PVP and PGNA are intimately mixed and the PGNA is in a random conformation. Hydrophobic interactions between PGNA and PVP are evident in dilute aqueous solutions of all three adducts, while Na+ ions of PGNA remain as free ions. 2D-NOESY 1H NMR spectra of the EAM and UC adducts are very similar and show a strong correlation between the α-proton of PGNA with a pyrrolidone ring (no. 3 and no. 4 protons) and β-protons of PGNA with a pyrrolidone ring (no. 5 proton). In contrast, regarding the DRM adduct, only the α-proton of PGNA interacts with the pyrrolidone ring (no. 3 and no. 4 protons), presumably due to the orientation of the pyrrolidone ring at the organic phase–water interface of the reverse micelle, which causes the proton in position 5 of the ring to be buried in the organic phase. All three adducts dissociate in water to form free PVP and PGNA. However, the DRM adduct dissociates faster than other two, presumably due to reduced hydrophobic interactions. Differences in composition and properties observed for the non-covalent adducts may be attributed to the differences in intermolecular (hydrophobic) interactions imposed on the two components, PGNA and PVP, during each method of preparation.

Basicity of a novel macrocycle containing thiopyrimidine and uracil moieties in various water-organic mixtures

The acid–base behavior of the novel macrocycle, containing thiopyrimidine and uracil moieties 32-trimethyl-23,36-dioxo-15,19-dithio-2,9,13,20,24,31,34,35-octaazatatracyclo [28,3,110,14,120,24]hexatriacontaheptaen-1(34),10(35),11,13,21,30,32 (1) and the acyclic 1,6-bis[4-(N,N-dimethylamino)-6-methylpyrimidinile-2-thio]hexane (2) were studied by potentiometric, UV-Vis, 1H, NMR spectroscopic methods in water–dimethyl sulfoxide (methanol, 1,4-dioxane) solutions and at the interface between water and chloroform phases. The data obtained indicate, that thiopyrimidine nitrogens are the protonation sites of both 1 and 2. The protonation of 2 occurs in one step, while 1 is protonated stepwise in the pH range 9–2.5. The NMR data indicate that the intramolecular interaction between protonated pyrimidine and uracil moieties is the main reason for the stabilization of protonated forms of 1. The protonation constants of 1 were found to be different in various water–organic mixtures, which is in accord with the different 1H NMR spectra of 1 in various solvents. The protonation of 1 at the water–organic phase boundary is effected by the extraction of [1·2H]2+ into the aqueous phase, which can be regarded as a way of obtaining its water -soluble form.

Ruthenium colloids: A new catalyst for alkane oxidation by tBHP in a biphasic water-organic phase system

Efficient and highly selective conversion of cyclooctane into cyclooctanone is obtained under pure biphasic conditions through t-butylhydroperoxide activation by the in situ formation of colloidal ruthenium species arising from RuCl 3, 3H 2O. Model extension experiments to other cycloalkanes are also discussed.

Dicyclohexano 18 crown 6 in butanol-octanol mixture: A promising extractant of Sr(II) from nitric acid medium

The extraction of strontium from nitric acid medium was investigated employing DCH18C6 in aliphatic alcohols as the diluents. 80% Butanol-20% octanol mixture was found to give higher D Sr values as compared to other alcohols investigated. A linear correlation between the organic phase water content and D Sr was observed, based on which the extraction mechanism was postulated. Effect of anion, cation, extractant concentration, nitric acid concentration and temperature on D Sr was also studied. Conditions for recovery (>90%) were arrived at and selectivity with respect to other interfering fission products was observed with most of the metal ions studied.

Low temperature organic phase biocatalysis using cold-adapted lipase from psychrotrophic Pseudomonas P38

Lipase produced by a psychrotroph, Pseudomonas fluorescens P38, was found to catalyse the synthesis of butyl caprylate in n-heptane at low temperatures. The optimum yield of ester synthesis was 75% at 20 °C with an organic phase water concentration of 0.25% ( v v ). The results are discussed in terms of the structural flexibility of psychrotroph-derived lipase and the activity of this enzyme within a nearly anhydrous organic solvent phase.

Extraction of Cesium from Acidic Nitrate Media Using Macrocyclic Polyethers : The Role of Organic Phase Water*

ABSTRACT A simple correlation has been observed between the extraction of cesium nitrate from nitric acid solution by several macrocyclic polyethers dissolved in any of a variety of oxygenated, aliphatic diluents and the concentration of water present in the organic phase. This correlation is attributed, in part, to the extraction of the hydrated nitrate anion and its solvation by the diluent, facilitated by the high concentrations of dissolved water. Cation solvation by the diluent is also shown to play an important role in determining the efficiency of extraction. As was the case for strontium extraction by dicyclohexano-18-crown-6 and its derivatives, the highest distribution ratios for cesium are typically obtained for C-5 and C-6 alcohols and ketones.

Organic-phase enzyme biosensor for moisture determination in food products

A novel biosensing scheme for measuring the moisture content of food products is described. The strategy relies on a recently developed organic-phase water biosensor, involving the stimulation by water of the biocatalytic activity of the immobilized tyrosinase in the presence of catechol substrate. The dynamic properties of the water detector were exploited for rapid and reproducible flow injection assays of food products, such as butter, margarine and lyophilized products. The moisture contents found, correlate well with the values obtained by standard official methods. Such a development should facilitate rapid quality control testing in the food industry

Nonlinear regression analysis of reversible ion transfer in current-scanning voltammetry

A nonlinear regression model of reversible ion transfer across the interface between aqueous and organic phases is derived theoretically with consideration of background current and resistance. We used the Marquardt nonlinear regression method to fit the response curves for reversible ion transfer of tetramethyl ammonium and vitamin B1 across the water—organic phase interface and simultaneously estimated values of their aqueous diffusion coefficients, charge-transfer resistances, half-wave potentials and the background current. The analysis of the residuals indicates that the model reflects the true behavior of the test systems. The results obtained show that the technique is not sensitive to the experimental conditions.