Hydrophobic Amines Research Articles

Boc Protection for Diamine-Appended MOF Adsorbents to Enhance CO2 Recyclability under Realistic Humid Conditions.

Among the various metal-organic framework (MOF) adsorbents, diamine-functionalized Mg2(dobpdc) (dobpdc4- = 4,4-dioxidobiphenyl-3,3'-dicarboxylate) shows remarkable carbon dioxide removal performance. However, applying diamine-functionalized Mg2(dobpdc) in practical applications is premature because it shows persistent performance degradation under real flue gas conditions containing water vapor owing to diamine loss during wet cycles. To address this issue, we employed hydrophobic carbonate compounds to protect diamine groups in een-Mg2(dobpdc) (een-MOF, een = N-ethylethylenediamine). tert-Butyl dicarbonate (Boc) reacted rapidly with diamines at the pore openings of MOF particles to form dense secondary and tertiary hydrophobic amines, effectively preventing moisture ingress. The Boc-protected een-MOF-Boc1 maintained excellent CO2 adsorption even under simulated flue gas conditions containing 10% H2O. This observation indicates that Boc protection renders een groups intact during repeated wet cycles, suggesting that Boc-protected een groups are resistant to replacement by water molecules. To increase the practicability of the MOF adsorbent, we fabricated een-MOF/PAN-Boc1 composite beads by shaping MOF particles with polyacrylonitrile (PAN). Notably, the composite beads maintained their CO2 adsorption performance even after repeating the temperature swing adsorption process more than 150 times in 10% water vapor. Furthermore, breakthrough tests showed that the dynamic CO2 separation performance was retained under humid conditions. These results demonstrate that Boc protection provides an easy and effective way to develop promising adsorbents with high CO2 adsorption capacity, long-term durability, and the properties required for postcombustion applications.

Treating oily solids using a CO2-responsive surfactant-free microemulsion: An enhanced approach for oil removal from solid surfaces

Because switchable water is difficult to apply directly for oil removal, an enhanced approach to improve oil removal is proposed using a surfactant-free microemulsion (SFME) containing switchable water. The SFME is formed using switchable water (aqueous N, N-dimethylethanolamine (DMEA) or N,N-dimethylbutylamine (BDEA)) and a hydrophobic amine (N - butyldiethanolamine (DMBA)). The single-phase region for preparing the SFME is determined using a ternary phase diagram, and the microstructure types are distinguished using the conductivity method. The pH changes and dynamic laser scattering test results demonstrate that the SFME exhibits irreversible transformation behavior regulated by CO 2 . Moreover, the recovered SFME containing BDEA has a microstructure with a smaller particle size after removing the CO 2 by bubbling N 2 at 65°C, which is attributed to the higher proportion of DMEA than that of BDEA. In addition, dodecane and diesel oil are shown to dissolve in the SFME, and the oil solubility of the SFME increases with increasing oil phase (DMBA) content. The interface free energy theory reveals that the oil is more easily detached with the addition of SFME than with switchable water only owing to the reduced interface free energy of oil on the solid surface. Thus, an enhanced approach for removing oil is proposed to wash oil sands, where the oil removal efficiency of switchable water can be improved by using SFMEs containing switchable water.

SPECTROPHOTOMETRIC DETERMINATION OF MOLYBDENUM AND TUNGSTEN IN THE SOIL OF THE JABRAYIL REGION WITH 2-HYDROXY-5-HALIGENTHIOPHENOLS AND AROMATIC AMINES

In the interaction of molybdenum and tungsten with 2-hydroxy-5-halogenthiophenols, mixed-ligand complexes (MLC) extractable with chloroform are formed. Aniline, N-methylaniline, and N, N-dimethylaniline were used as the hydrophobic amines. The conditions for the extraction-photometric determination of molybdenum and tungsten are found. The best extractants were chloroform, dichloroethane and carbon tetrachloride. In a single extraction with chloroform, 97.8–98.2% of molybdenum and tungsten are recovered in the form of MLC (in the case of C2H4Cl2 and CCl4, 95–96% of molybdenum and tungsten are recovered). Molybdenum and tungsten MLC extracts obey the basic law of light absorption at concentrations of 0.2–20 and 0.2–19 μg/mL, respectively. It was established by the Nazarenko method that the complexing form of molybdenum and tungsten is MeO (OH)2+. It was found that MLC are formed at pHopt. 1.8-5.1. The maximum in the light absorption spectrum is observed at 457–538 nm. The molar light absorption coefficient is (3.2-4.2) ×104. It has been proven that molybdenum (VI) and tungsten (VI) are reduced to Me(V) by the reagent itself upon formation of a complex with halothiophenols. Keywords: molybdenum, tungsten, 2-hydroxy-5-halogenthiophenol, extraction-photometric method, hydrophobic amines

Sustainable associative thickeners based on hydrophobically modified ethoxylated poly(hydroxy-urethane)s end-capped by long alkyl chains

Hydrophobically modified ethoxylated urethanes (HEURs) are associative polymers applied as thickening additives in various waterborne systems, such as emulsions, coatings and printing inks. Their conventional synthesis, based on diisocyanates, poses environmental and health threats during both manufacture and application. Hence, in this paper we present an approach for the next generation of sustainable and CO2-rich polyurethane rheological modifiers – isocyanate-free HEURs (IFHEURs) obtained through poly(hydroxy-urethane) route. The hydrophilic core of the IFHEURs was prepared by step-growth polyaddition between diamine and poly(ethylene glycol) bis(cyclic carbonate) – synthesized using CO2 as a green source of the carbonate bonds. Such obtained prepolymer with terminal carbonate groups was subsequently modified with hydrophobic amines using reactive extrusion method, which enabled efficient homogenisation of the viscous reaction systems and reaching high end-capping functionality after only 2 h. In contrast to previously reported studies, the synthetic procedure was both solvent- and catalyst-free and allowed to incorporate up to 11 wt% of CO2 into the backbone of the final products. The structural analysis of the obtained IFHEURs using NMR and FT-IR spectroscopy and MALDI-ToF mass spectrometry confirmed obtaining the desired telechelic architecture resembling standard HEUR materials. The associative behavior of the IFHEURs in aqueous solutions was addressed in a rheological study, which revealed typical thickening mechanisms exhibited by rheological additives.

A Reductive Aminase Switches to Imine Reductase Mode for a Bulky Amine Substrate.

Imine reductases (IREDs) catalyze the asymmetric reduction of cyclic imines, but also in some cases the coupling of ketones and amines to form secondary amine products in an enzyme-catalyzed reductive amination (RedAm) reaction. Enzymatic RedAm reactions have typically used small hydrophobic amines, but many interesting pharmaceutical targets require that larger amines be used in these coupling reactions. Following the identification of IR77 from Ensifer adhaerens as a promising biocatalyst for the reductive amination of cyclohexanone with pyrrolidine, we have characterized the ability of this enzyme to catalyze couplings with larger bicyclic amines such as isoindoline and octahydrocyclopenta(c)pyrrole. By comparing the activity of IR77 with reductions using sodium cyanoborohydride in water, it was shown that, while the coupling of cyclohexanone and pyrrolidine involved at least some element of reductive amination, the amination with the larger amines likely occurred ex situ, with the imine recruited from solution for enzyme reduction. The structure of IR77 was determined, and using this as a basis, structure-guided mutagenesis, coupled with point mutations selecting improving amino acid sites suggested by other groups, permitted the identification of a mutant A208N with improved activity for amine product formation. Improvements in conversion were attributed to greater enzyme stability as revealed by X-ray crystallography and nano differential scanning fluorimetry. The mutant IR77-A208N was applied to the preparative scale amination of cyclohexanone at 50 mM concentration, with 1.2 equiv of three larger amines, in isolated yields of up to 93%.

Determination of iron (III) in environmental objects by photometric method with acetylacetone derivatives

Organic reagents containing three carbonyl groups based on acetylacetone, 2,4-diacetyl-3-phenyl-5-methyl-5-hydroxyhexanone (R1), 2,4-diacetyl-3-(3'-nitrophenyl)-5-hydroxy-5-methylcyclohexanone (R2) and 3-acetyl-4,6-diphenylgensandione-2,6 (R3), were synthesized. Their absorption spectra were studied at various pH values of the medium, and the acidity constants were determined by potentiometric titration. It was found that the reagents are monobasic acids and, depending on the acidity of the medium, can be in the molecular (HR) or anionic (R-) form. Formation of iron (III) complexes with synthesized reagents in the presence of hydrophobic amines, 1,10-phenanthroline (Phen), diantipyrylmethane (DAM) and diantipyrylphenylmethane (DAPM) was studied. It was established that mixed ligand complexes with the components ratio of 1:1:1 were formed in the presence of hydrophobic amines. At the same time bathochromic shifts in the absorption spectra were observed and the maximum yield was noted in a more acidic medium compared to the corresponding single ligand complexes. The influence of the reagents concentration, time and temperature on the formation of mixed ligand complexes was studied, and the stability constants were determined by various methods. It was shown that iron (III) in the form of mixed ligand complexes, Fe(III)-R1-DAM, Fe(III)-R2-Phen and Fe(III)-R3-DAM, can be determined with high selectivity in the presence of large excess of other metal cations. The developed methods were tested on fruits – strawberries, apricots, cherries, white cherries and two varieties of apples (Golden Ahmadi and Simirenko), and natural waters – drinking water taken from a tap in the BSU laboratory and Caspian Sea water taken near the Turkan village of Baku city.

Monitoring and investigating reactive extraction of (di–)carboxylic acids using online FTIR – Part II: Reaction equilibria, reaction kinetics and competition within the complex formation between itaconic acid and several amine extractants

The downstream processing of biocatalytically produced (di–)carboxylic acids still is a challenging task. One innovative approach, demonstrating industrial applicability, applies an initial reactive extraction (RE) using hydrophobic amine extractants into an organic solvent, followed by a subsequent back-extraction (BE) using water soluble amine extractants into a (fresh) aqueous solution. Although showing promising results in terms of yield and selectivity, state-of-the-art amine extractant selection is only based on trial-and-error screening approaches. Thus, to enable an optimized process design and thereby optimized downstream processing, a deeper understanding of RE and BE on a molecular level is crucial.Within this work, we successfully applied an experimental setup incorporating online Fourier Transform Infrared (FTIR) spectroscopy to elucidate influencing factors on RE and BE as well as to provide a guideline for an optimized selection of amine extractants. Investigations on the kinetics of complex formation between itaconic acid (IA) and tri-n-octylamine (TNOA) in 1-decanol revealed the reaction order to be zero in TNOA, indicating that mass transfer is the rate limiting step in RE. Reaction equilibrium investigations revealed that for all IA - amine extractants combinations in 1-decanol reaction equilibrium was almost completely on the product (complex) side. The strength of the acid-extractant complexes was evaluated using FTIR experiments, providing a novel approach / methodology to efficiently select an optimal combination of amine extractants for RE and BE. Applying the novel online FTIR spectroscopy setup allowed to monitor a complete process sequence of RE and BE of IA with selected amine extractants, validating the proposed guidelines for an optimized selection of amine extractants. The results of this work will facilitate the definition of appropriate RE and BE systems for biocatalytically produced (di–)carboxylic acids.

Synthesis of hydrophobically modified ethoxylated non-isocyanate urethanes (HENIURs) and their use as rheology additives

Telechelic associative polymers such as Hydrophobically modified ethoxylated urethanes (HEURs) are an important class of rheology additives used in many industrial fields allowing a precise control of the rheology. To avoid the use of toxic isocyanates, more eco-friendly HEURs were synthesized based on the cyclo-carbonate/amine addition reaction. Hydrophobically modified ethoxylated hydroxyurethanes (HEHURs) were thus obtained by the aminolysis of telechelic 5-membered cyclic carbonates functionalized PEG in the presence of hydrophobic amines of 14, 16 and 18 carbons. The rheological properties (G’, G’’ and η*) of these amphiphilic structures were investigated, as well as the influence of different parameters such as: temperature (5–25 °C), concentration (10–20 wt%) and hydrophobic chain length. Their rheological properties were also compared to isocyanate-based equivalent structures (HEURs). Finally, HEHURs were used in latex solution to illustrate their potential use as rheology additives and their thickening efficiency at 0.25 wt%. Mainly Newtonian to fully pseudoplastic profiles were obtained depending on the variation of the hydrophobic chain length.

Selective hydrophobic decoration of metal-organic framework for effective removal of ppb-level CH3I from humid streams

Recently, effective removal of toxic gases from humid streams has been an urgent global issue, especially at low concentrations due to increase in air pollutant emission standards. In this work, a series of selectively modified MIL-101 s was prepared by blocking coordinatively unsaturated sites (CUSs) with hydrophobic amine compounds containing –F or long alkyl groups. The nucleophilic quinuclidine (QN) was consecutively encapsulated into the pores of hydrophobic MIL-101 s to remove CH3I by alkylation. The direct correlation between the hydrophobic index (HI) of adsorbents and the CH3I removal performance in a humid environment was systematically investigated for the first time by progressively blocking the CUSs with different amounts of hydrophobic amines including 4-(trifluoromethyl) benzylamine (TFM-BA). Among them, QN@MIL-101-TFM-BA exhibited the unprecedented removal efficiency exceeding 99.999% at 303 K and RH 95% for 11 days, outperforming over 280 times compared to the conventional adsorbents. The strong affinity between QN and CH3I is thoroughly investigated by X-ray photoelectron spectroscopy (XPS) and elemental mapping. MIL-101-TFM-BA showed outstanding removal performance even for HCHO, proving the versatile use of the prepared hydrophobic metal–organic frameworks adsorbents in realistic condition.

Water-assisted and protein-initiated fast and controlled ring-opening polymerization of proline N-carboxyanhydride.

The production of polypeptides via the ring-opening polymerization (ROP) of N-carboxyanhydride (NCA) is usually conducted under stringent anhydrous conditions. The ROP of proline NCA (ProNCA) for the synthesis of poly-L-proline (PLP) is particularly challenging due to the premature product precipitation as polyproline type I helices, leading to slow reactions for up to one week, poor control of the molar mass and laborious workup. Here, we report the unexpected water-assisted controlled ROP of ProNCA, which affords well-defined PLP as polyproline II helices in 2–5 minutes and almost-quantitative yields. Experimental and theoretical studies together suggest the as-yet-unreported role of water in facilitating proton shift, which significantly lowers the energy barrier of the chain propagation. The scope of initiators can be expanded from hydrophobic amines to encompass hydrophilic amines and thiol-bearing nucleophiles, including complex biomacromolecules such as proteins. Protein-mediated ROP of ProNCA conveniently affords various protein-PLP conjugates via a grafting-from approach. PLP modification not only preserves the biological activities of the native proteins, but also enhances their resistance to extreme conditions. Moreover, PLP modification extends the elimination half-life of asparaginase (ASNase) 18-fold and mitigates the immunogenicity of wt ASNase >250-fold (ASNase is a first-line anticancer drug for lymphoma treatment). This work provides a simple solution to a long-standing problem in PLP synthesis, and offers valuable guidance for the development of water-resistant ROP of other proline-like NCAs. The facile access to PLP can greatly boost the application potential of PLP-based functional materials for engineering industry enzymes and therapeutic proteins.

Multivalent Display of Lipophilic DNA Binders for Dual-Selective Anti-Mycobacterium Peptidomimetics with Binary Mechanism of Action

Multivalent Display of Lipophilic DNA Binders for Dual-Selective Anti-Mycobacterium Peptidomimetics with Binary Mechanism of Action

Template‐Directed Synthesis of Bivalent, Broad‐Spectrum Hosts for Neuromuscular Blocking Agents**

AbstractWe report on the synthesis of bivalent water‐soluble calix[4]arene and calix[5]arene hosts, Super‐sCx4 and Super‐sCx5 as new broad‐spectrum supramolecular binders of neuromuscular blocking agents (NMBAs). Synthesis was achieved using the target bisquaternary amine NMBAs as a template to link two highly anionic p‐sulfonatocalixarene building blocks in aqueous solution. Bivalent anionic hosts Super‐sCx4 and Super‐sCx5 bind by engaging both quaternary amines present on a variety of NMBAs. We report low μM binding to structurally diverse alkyl, steroidal, curarine and benzylisoquinoline NMBAs with high selectivity over the neurotransmitter acetylcholine and a variety of other hydrophobic amines.

Template-Directed Synthesis of Bivalent, Broad-Spectrum Hosts for Neuromuscular Blocking Agents.

We report on the synthesis of bivalent water-soluble calix[4]arene and calix[5]arene hosts, Super-sCx4 and Super-sCx5 as new broad-spectrum supramolecular binders of neuromuscular blocking agents (NMBAs). Synthesis was achieved using the target bisquaternary amine NMBAs as a template to link two highly anionic p-sulfonatocalixarene building blocks in aqueous solution. Bivalent anionic hosts Super-sCx4 and Super-sCx5 bind by engaging both quaternary amines present on a variety of NMBAs. We report low μM binding to structurally diverse alkyl, steroidal, curarine and benzylisoquinoline NMBAs with high selectivity over the neurotransmitter acetylcholine and a variety of other hydrophobic amines.

Исследование комплексообразования никеля(II) с 2,6-димеркапто-4-метилфенолом и аминофенолами

Complexing of nickel(II) with 2,6-dimercapto-4-methylphenol (DMMP) and hydrophobic amines was studied using physicochemical methods. Hydroxyl-containing amines-aminophenols (AP) were used as a hydrophobic amine. On the part of aminophenols, 2 (N, N-dimethylaminomethyl)-4-methylphenol (AP1), 2 (N, N-dimethylaminomethyl)-4-chlorophenol (AP2), and 2 (N, N-dimethylaminomethyl)-4-bromophenol (AP3) were used. Mixed-ligand complexes were formed in a weakly acidic medium (pHopt 4.6–6.4). Ni(II) is recovered by chloroform by 98.6–99.5% in the form of a mixed-ligand complex (MLC) per single extraction. The optimal conditions for the formation and extraction of these compounds are 1.12 × 10-3 mol/L concentration of DMMP and 0.88 × 10-3 mol/L – AP. Changing the concentration of the reagents does not change the composition of the complexes. MLC of Ni(II) with DMMP and AP are stable in aqueous and organic solvents and do not decompose within three days and for more than a month after extraction. The ratio of reacting components in MLC corresponds to Ni (II): DMMP : AP = 1 : 2 : 2. in the formation of MLC, the coordinating ion is Ni2+. Complexing proceeds with the displacement of a proton from a DMMP molecule. Maximum light absorption is observed at λ = 520–530 nm. The molar coefficients of light absorption are (3.78-3.95) × 10 4. Based on the obtained data photometric methods for the determination of nickel in various industrial and natural objects were developed.

SPECTROPHOTOMETRIC STUDY OF NICKEL (II) COMPLEXES WITH 2- HYDROXYTHIOLPHENOL AND ITS DERIVATIVES IN THE PRESENCE OF HYDROPHOBIC AMINES

The complexation reactions of nickel (II) with 2-hydroxythiophenol and its derivatives (2,5- dihydroxythiophenol, 2-hydroxy-5-chlorothiophenol, 2-hydroxy-5-bromothiophenol, and 2-hydroxy-5- iodothiophenol) in the presence of hydrophobic amines were studied by spectrophotometric methods. Aniline and N, N-dimethylaniline were used as hydrophobic amines. It found that mixed-ligand complexes (MLC) are formed in a weakly acidic medium (pH 2.3-8.0). The maximum in the light absorption spectrum of the complexes is observed at λ = 620-650 nm. The molar coefficients of light absorption are (4.1-4.3)×104 . The best extractants were chloroform, dichloroethane and carbon tetrachloride. With a single extraction with chloroform, 97.8-98.4% of nickel is extracted in the form of MLC. Based on the data obtained, photometric methods for the determination of nickel in various objects were developed.

Simultaneous determination of nine atmospheric amines and six inorganic ions by non-suppressed ion chromatography using acetonitrile and 18-crown-6 as eluent additive

Atmospheric amines contribute to the nucleation and initial growth of new particles as well as secondary organic aerosol formation, influencing the radiative balance of the Earth's atmosphere. In this study, we develop an ion chromatography (IC) method for separating and quantifying the nine most abundant amines (methylaminium (MMAH+), dimethylaminium (DMAH+), trimethylaminium (TMAH+), ethylaminium (MEAH+), diethylaminium (DEAH+), propylaminium (MPAH+), butylaminium (MBAH+), ethanolaminium (MEOH+), and triethanolaminium (TEOH+)) from six common inorganic species in atmospheric aerosols. The retention times of the amines were altered by the addition of acetonitrile to the eluent because acetonitrile can reduce the adsorption of hydrophobic amines on the stationary phase. The developed method achieved the successful separation of DEAH+ and TMAH+ from inorganic cations, which often coelute with each other in established IC methods. The interference of K+ on the determination of MEAH+ was eliminated by the complexation of K+ with 18-crown-6, which prolonged the retention time of K+. Finally, 9 target amines and 6 common inorganic cations were separated, with a resolution Rs ≥ 1.2 for DEAH+ and MPAH+ and Rs > 1.5 for other species. The detection limits varied in the range of 0.34-1.48 ng for the 9 amines and 0.19-0.56 ng for the inorganic cations. The developed method was successfully applied for the determination of low molecular weight amines and inorganic cations in PM2.5 collected from an urban site in Shanghai and an isolated coast of Chongming Island. Eight amines were detected in the urban samples, in which MMAH+ and DMAH+ dominated. The average amine concentration in the urban aerosols was 76.3 ± 38.4 ng m−3, which is approximately 4-fold higher than those in the marine samples collected from the coast.

Mixedligand complexes of uranium (VI) with dithiolophenols and hydrophobic amines in photometric analysis

AbstractIn this paper we studied the interaction of uranium (VI) with with dithiolphenols (2,6‐dithiophenol, 2,6‐dithiol‐4‐methylphenol, 2,6‐dithiol‐4‐ethylphenol, 2,6‐dithiol‐4‐tert‐butylphenol), and hydrophobic amines by absorption spectroscopy method. The sudied hydrophobic amines are aniline, N–methylaniline, N,N–dimethylaniline, diphenylguanidine, triphenylguanidine, benzylamine, phenantrolin, dipyridyl, p‐aninopyridin, 2‐(N,N‐dimethylaminomethyl)‐4‐methylphenol and 2‐(N,N‐dimethylaminomethyl)‐4‐bromphenol. The optimal conditions for the formation and extraction of ionic associates were found and the ratios of components in the complexes were established. It was found that associates are formed in a weakly acidic medium (pHopt = 3.5‐7.1). The maxima in the light absorption spectra are observed at λ = 434‐478 nm. Molar coefficient of absorption is equal ε = (2.65‐3.62)•104. On the basis of the obtained data, photometric methods of uranium determination in various objects have been developed.

Robust phase transfer, 3D-assembly and SERS application of multi-shaped gold nanoparticles

A robust, fast and versatile phase transfer approach to the transfer of large hydrophilic multi-shaped gold nanoparticles from aqueous to organic phase was systematically investigated. The procedure uses the amphiphilic surfactant bis-(amidoethylcarbamoylethyl) octadecylamine (C18N3), which consists of a long alkane chain to provide hydrophobic properties and terminal amine groups for hydrophilic properties. Furthermore, the 3D-assembly behavior, plasmonic properties and surface-enhanced Raman scattering properties of the hydrophobic multi-shaped gold nanoparticles derived from the phase transfer method on the surface of mercapto-silica colloidal spheres were systematically investigate. The surfaces of mercapto-silica spheres immobilize gold nanoparticles through strong coordination interactions between gold cations and thiol groups and allow the direct assembly of large multi-shaped nanoparticles on supporting colloidal spheres. The size of the gold nanoparticles used in both 3D-assembly and phase transfer is much larger (as large as 55 nm) than any known reports to date. This assembly strategy will provide the research community with a highly versatile, configurable, and reproducible process for the preparation of various structures and great flexibility in incorporating multiple nanoparticle components.

Solvent Extraction of Cobalt (II) with 2, 6-dithiolphenol and its Derivatives in the Presence of Hydrophobic Amines

Mixed-ligand complexes of Cobalt(II) with dithiolphenol (DP) {2, 6-dithiolphenol (DTP) and its derivatives (2, 6-dithiol-4-methylphenol (DTMP), 2, 6-dithiol-4-propylphenol (DTPP), 2, 6-dithiol-4-tert-buthylphenol (DTBP)} in the presence of aminophenols (AP) have been studied by spectrophotometry. Extraction of mixed ligand complexes is maximal at pH 4.1-6.5. The optimal conditions for the formation and extraction of mixed-ligand compounds have been found and the ratios of components I the complexes have been determined. The Beer’s law was applicable in the range of 0.2-20 μg/ml. The effect of foreign ions and reagents on the extraction was studied. The method is free from common interferences. A procedure has been developed for extraction – spectroand#172;photometric determination cobalt in different objects (in steel, sewage water, bottom sediments, food and soil samples).

Solvent Extraction of Cobalt (II) with 2, 6-dithiolphenol and its Derivatives in the Presence of Hydrophobic Amines

Mixed-ligand complexes of Cobalt(II) with dithiolphenol (DP) {2, 6-dithiolphenol (DTP) and its derivatives (2, 6-dithiol-4-methylphenol (DTMP), 2, 6-dithiol-4-propylphenol (DTPP), 2, 6-dithiol-4-tert-buthylphenol (DTBP)} in the presence of aminophenols (AP) have been studied by spectrophotometry. Extraction of mixed ligand complexes is maximal at pH 4.1-6.5. The optimal conditions for the formation and extraction of mixed-ligand compounds have been found and the ratios of components I the complexes have been determined. The Beer’s law was applicable in the range of 0.2-20 μg/ml. The effect of foreign ions and reagents on the extraction was studied. The method is free from common interferences. A procedure has been developed for extraction – spectroand#172;photometric determination cobalt in different objects (in steel, sewage water, bottom sediments, food and soil samples).