Nickel extraction by 2-hydroxy-5-tert-butylbenzaldehyde oxime

Nickel extraction from aqueous solutions between pH 3 and 10 using 2-hydroxy-5-t-butylbenzaldehyde oxime was investigated. Iso-octane, octane, xylene and dichloro-ethane were used as diluents. It was found that nickel extraction is dependent upon the equilibrium pH, the mol ratio of oxime : nickel and the nature of the diluent. The composition of the nickel-oxime complex is in the ratio of 1:2. Extraction data, infrared spectra and cryoscopic measurements have shown the association of the oxime in the organic phase and the solvation of the nickel complex by the oxime molecules. The degree of solvation was found to be higher in dichloroethane than in octane.     

Copper extraction from diluted sulphate solutions by 2-hydroxy-5-tert-butylbenzaldehyde oxime

A study of the influence of the equilibrium pH of the aqueous phase and the oxime concentration in octane, isooctane, xylene and ethylene dichloride showed that 2-hydroxy-5-tert-butylbenzaldehyde oxime (HBBO) forms a yellow complex with copper with a molar ratio of ligand: metal equal to 2:1. The same results were obtained using Job's and slope ratio methods. The diluents examined influence the copper extraction by HBBO, especially at low pH values in the aqueous phase. The order of extractability is as follows: isooctane=octane>xylene>ethylene dichloride. At low pH values, HBBO shows greater extraction power than 2-hydroxy-alkyl-benzophenone oximes. Computer calculations suggest that polymerisation of the complex does not occur. However, a solvation of the complex occurs when excess of the oxime is used.     

Extraction of copper from acid sulphate solutions by 2-hydroxy-5-(1,1,3,3-tetramethylbutyl)-benzaldehyde,-acetophenone and -benzophenone oximes

2-Hydroxy-5-(1,1,3,3-tetramethylbutyl)-benzaldehyde E-oxime ( 1 ), 2-hydroxy-5-(1,1,3,3-tetramethylbutyl)-acetophenone E-oxime ( 2 ) and 2-hydroxy-5-(1,1,3,3-tetramethylbutyl)-benzophenone E-oxime ( 3 ) were synthesized and used for copper extraction from acidic sulphate solutions. The dissociation constants of the phenolic group of the oximes and the stability constants for their complexes with copper were determined. An extraction model is discussed taking under consideration the association of the oxime and the solvation of the complex. It was found that 1 can extract copper more efficiently from acidic aqueous solutions and at a higher rate than 2 and 3. 1 is a stronger acid than 2 and 3 . However, it is a weaker acid than the Z isomer of 3 . The proposed model fits the experimental data well. When the oxime is used in excess, solvation of the copper complex seems probable.     

Study of the Kinetics of Copper Extraction with (anti)-2-Hydroxy-5-nonylbenzophenone Oxime Using a Rotating Diffusion Cell

Abstract

A rotating diffusion cell was used to study the chemical reaction in which copper is transferred from an aqueous sulfate phase to an organic phase containing a copper-complexing agent (purified anti-2-hydroxy-5-nonylbenzo-phenone oxime) dissolved in n-decane. A mathematical model was developed to describe the contributions of the kinetic and diffusive resistances to the overall resistance to mass transfer. Application of this model to the experimental data enabled an overall rate equation for the reversible copper extraction reaction to be written. The active oxime species in the extraction reaction was found to be the monomer with first-order kinetics. The extraction reaction rate was also found to be dependent on aqueous phase hydrogen ion concentration with negative first-order kinetics. The extraction rate constant was determined as 1.3 × 10^?5 cm/s. Assumption that the reverse rate is dependent on hydrogen ion concentration with first-order kinetics enabled the reverse rate constant to be calculated as 6.8 × 10^?3 cm⁴/mol·s.     

Dehydration of 2-(2-Arylethyl)-2-hydroxy-4-oxopentanoic Acids and their hydrazones to form heterocycles

Dehydration of 2-(2-arylethyl)-2-hydroxy-4-oxopentanoic acids 1 with hydrochloric acid/acetic acid, affords 3-(2-arylethyl)-5-hydroxy-5-methyl-2(5H)-furanones 4 . Compounds of type 1 and 4 represent suitable precursors for the formation of pyridazin-3-ones 7 as they smoothly react with hydrazine. A new series of s-triazolo[4,3-b]pyridazin-3-ones 12 and tetrazolo[1,5-b]pyridazines 15 are obtained from the 3-chloropyridazines 11 upon treatment with semicarbazide and sodium azide, respectively. Reaction of 11 with phenyl- acetyl-hydrazine provides 3-benzyl-6-phenyl-8-(2-phenyl-ethyl)-s-triazolo[4,3-b]pyridazine 13 via dehydrative cyclization of the intermediate 14 which was clarified to exhibit tautomeric equilibria between enol–hydrazine form A and keto–hydrazine form B by means of ¹H and ¹³C NMR spectroscopy. Attempts to synthesize 3-alloxy-pyridazines 18 by reacting 11 with sodium alloxide afford N-allyl compounds 17 .     

A synthesis of 4-hydroxy-2-trans-nonenal and 4-(3H) 4-hydroxy-2-trans-nonenal

4-Hydroxy-2-trans-nonenal, the most abundant and toxic unsaturated aldehyde generated during membrane lipid peroxidation, was synthesized starting from fumaraldehyde dimethyl acetal. In the first step of the synthesis, the fumaraldehyde dimethyl acetal was partially hydrolyzed using amberlyst catalyst to obtain the monoacetal. The 4-hydroxy-2-trans-nonenal was synthesized by the Grignard reaction of the fumaraldehyde monoacetal with 1-bromopentane. 4-Hydroxy-2-trans-nonenal, obtained as its dimethylacetal, was oxidized to its corresponding 4-keto derivative using pyridinium chlorochromate buffered with sodium acetate as the oxidizing agent. 4-(³H) 4-Hydroxy-2-trans-nonenal was obtained in one step by the sodium borotriteride reduction of the 4-keto derivative.     

EFFECT OF HYDROXYOXIME HYDROPHOBICITY UPON RATE OF COPPER EXTRACTION WITH 2-HYDR0XY-5-ALKYLBENZ0PHEN0NE OXIMES IN THE PRESENCE OF α-ACYLOIN OXIMES

ABSTRACT

Effects of α-acyloin oximes of various hydrophobicity upon copper(II) extraction rates with 2-hydroxy-5-alkylbenzophenone oximes was studied. Extraction rate depends mainly upon the hydrophobicity of 2-hydroxy-5-alkylbenzophenone oxime and sharply decreases when its hydrophobicity rises. The effect of a-acyloln oximes is small and more pronounced for more and less hydrophobic 2-hydroxy-5-alkylbenzophenone oximes and a-acyloin oximes, respectively, rising with the decrease of the aqueous phase acidity.     

COPPER EXTRACTION FROM CHLORIDE SOLUTIONS WITH MIXTURES OF SOLVATING AND CHELATING REAGENTS

ABSTRACT

Equimolar mixtures of N,N,N',N'-tetrahexylpyridine-3,5-dicarboxamide (L) with 2-hydroxy-5-t-octylbenzophenone oxime or l-phenyldecane-l,3-dione (HB), were used to extract copper from chloride solutions of various concentration of chloride ions. Chloride ions were then scrubbed out with water or ammoniacal solutions and copper was transferred from the solvate CUCl₂L₂ to chelate CuB₂- Both studied systems permit effective extraction of copper and removal of chloride ions from the organic phase. Some protonation of solvating reagent L occurs, however, when copper is stripped from the chelate with hydroxyoxime. This negative effect can be suppressed when 1-phenyl decane-1,3-dione is used as a chelating agent. The scrubbing of chloride ions must be then carried out with ammoniacal solutions to avoid simultaneous stripping of copper.     

NONDISPERSIVE LIQUID-LIQUID EXTRACTION OF COPPER AND ZINC FROM AN AQUEOUS SOLUTION BY DEHPA AND LIX 984 IN A HOLLOW FIBER MEMBRANE MODULE

ABSTRACT

A liquid-liquid extraction procedure was used to study the amounts of Zn²⁺ and Cu²⁺ that could be simultaneously extracted from aqueous solution with di(2-ethylhexyl) phosphoric acid (DEHPA) and LIX 984 diluted with n-heptane at equilibrium. LIX 984 is a 1:1 volume blend of LIX 860 (5-dodoecylsalicylaldoxime) and LIX 84 (2-hydroxy-5-nonylacetophenone oxime). At equilibrium, a 0.3 mol/L DEHPA-20% (v/v) LIX 984 solution extracted 99% of both the zinc and copper from a solution that had 100 ppm of each metal.

A polysulfone hollow-fiber membrane module with 1 mm ID and 5,000-molecular weight cutoff was used to study the amounts of Zn²⁺ and Cu²⁺ that could be simultaneously extracted with a mixture of DEHPA and LIX 984. The aqueous and organic streams were operated at 100% recycle. With a 0.6 mol/L DEHPA-10% (v/v) LIX 984 solution, a 90.5 ± 1.7% (s.d.) extraction of zinc and a 93.70 ± 0.79% (s.d.) extraction of copper was obtained after 180 min.     

Separation and recovery of heavy metals from concentrated smelting wastewater by synergistic solvent extraction using a mixture of 2-hydroxy-5-nonylacetophenone oxime and bis(2,4,4-trimethylpentyl) -phosphinic acid

Extraction and separation of copper, zinc, nickel, and cadmium from calcium and magnesium in concentrated smelting wastewater by synergistic solvent extraction using a mixture of 2-hydroxy-5-nonylacetophenone oxime (Mextral 84H) and bis(2,4,4 -trimethylpentyl)-phosphinic acid (Cyanex 272) in an aliphatic diluent (DT-100) was studied. The effects of extractant concentrations, equilibrium pH, organic-to-aqueous phase ratios, system temperature, and extraction and stripping efficiencies on the extraction performance of the heavy metals were investigated. Extraction of pH isotherms showed that addition of Cyanex 272 to Mextral 84H causes obvious synergistic shifts for zinc and cadmium and a slightly antagonistic shift for nickel. The separation factor of cadmium over magnesium was 155.7 and the ΔpH₅₀ values between the metals were over 1.00 pH units. Semi-continuous tests for the metals extraction, scrubbing, and stripping were conducted in a continuous extraction apparatus with conditions further optimized for separation of the metals. Nearly 100% of the copper and nickel and over 98% of the zinc and cadmium were recovered with less than 0.1 mg/L copper and nickel, 26 mg/L of zinc, and 10 mg/L of cadmium remaining in the raffinate. A process in which all valuable metals are extracted simultaneously and stripped selectively at optimal conditions is proposed that is entirely feasible for the separation of copper, zinc, nickel, and cadmium from calcium and magnesium in concentrated smelting wastewater. The study determines the fundamental parameters for the treatment of smelting wastewater by solvent extraction.     

The effect of intermittent and continuous heating of soybean oil at frying temperature on the formation of 4-hydroxy-2-trans-nonenal and other α-, β-unsaturated hydroxyaldehydes

4-Hydroxy-2-trans-nonenal (HNE) is a cytotoxic secondary lipid peroxidation product of linoleic acid. Previous investigations in this laboratory showed that HNE is formed in thermally oxidized soybean oil, which is high in linoleic acid. Continuous exposure of the oil to frying temperature (185°C) for up to 6 h graduallyincreased the formation of HNE and other polar lipophilic aldehydes. Additional investigations in this laboratory showed that HNE is absorbed into food fried in thermally oxidized oil in the same concentration as was found in the oil. In the present experiment, the effect of intermittent heating on the formation of HNE in soybean oil was compared with continuous heating. Soybean oil samples were heated either for 1 h each day for five sequential days or for 5 h continuously at 185±5°C. The thermally oxidized soybean oil samples were analyzed by HPLC for the presence of HNE and three other polar lipophilic α-,β-unsaturated hydroxyaldehydes: 4-hydroxy-2-trans-hexanal, 4-hydroxy-2-trans-octenal, and 4-hydroxy-2-trans-decenal. Under intermittent and continuous heating over a total of 5 h, the concentration of these compounds increased similarly. These results indicate that the formation of HNE and other hydroxyaldehydes at frying temperature is a cumulative result of oxidation of PUFA over time.     

KINETICS MODEL FOR INTERFACIAL REACTION OF COPPER EXTRACTION WITH 1-(2'-HYDROXY-5'-NONYLPHENYL)-l-ETHANONE (E)-OXIME AND 1-(2'-HYDROXY-5'-METHYLPHENYL)-1-DECANONE (E)-OXIME

Abstract

A kinetic model for the interfacial reaction of copper extraction with Individual 1-(2'-hydroxy-5'-nonylphenyl)-1-ethanone (E)-oxime and 1-(2'-hydroxy-5'-methylphenyl)-1-decanone (E)-oxime having the same hydrophobicity was used to interpret the effect of hydroxyoxime partition and interfacial activity upon the rate of copper extraction from acidic sulfate solutions. Due to similar hydrophobicity of studied extractants the proposed model, which is very sensitive to the errors of the partition coefficient determination, cannot support any version of extraction mechanism.     

The surface excess and the rate of copper extraction by hydroxyoximes

The interfacial tension is determined for some model 2-hydroxy-5-alkylbenzophenone E-oximes, and the surface excess is calculated according to the different adsorption isotherms. The relationship between the rate of copper extraction and the surface excess is discussed. It is shown that, depending upon the adsorption isotherm used to calculate the surface excess, different relations both between the extraction rate and the surface excess and between the surface excess and the oxime concentration are obtained. The interfacial activity of hydroxyoximes is only a qualitative parameter suggesting the interfacial mechanism for copper extraction, and it cannot give strong evidence quantitatively supporting this mechanism. The predicted reaction orders against oxime demonstrate that the reaction between the oxime molecules from the sublayer and the absorbed intermediate complex is probably the limiting step.     

Kinetic and Thermodynamic Separation of Cu(II) and Fe(III) by Liquid-Liquid Extraction with a β-Hydroxy-oxime in Toluene

Abstract

A quantitative study of the thermodynamic and kinetic separation of Cu(II) and Fe(III) by liquid-liquid extraction with toluene solutions of the oxime 2-hydroxy-5-t-octyl (acetophenone oxime) has been conducted. On the basis of the stoichiometry, equilibrium constants, rate laws and rate constants of the extraction reactions of Cu(II) and Fe(III) an equation has been derived which describes how the separation of Cu from Fe varies with the chemical composition of the system, the hydrodynamics of the extracting apparatus and the contact time between the aqueous and the organic phases. Our results show that separations which are not feasible thermodynamically are possible when the contact time between the two phases is kept much shorter than that required to reach equilibrium.     

Extraction of Copper(II) Ions from Chloride and Sulphate Solutions Using Hydrophobic Pyridyl Ketoximes

Hydrophobic pyridyl ketoximes: 1-(2-pyridyl)tridecan-1-one oxime, 1-(3-pyridyl)tridecan-1-one oxime and 1-(4-pyridyl)tridecan-1-one oxime have been synthesized and investigated as extractants of copper(II) ions. Removal of metal ions was conducted from chloride, sulphate, and sulphate/chloride solutions. The influence of pH of aqueous solutions, copper(II), chloride, and sulphate ions and ligand concentration for extraction process were studied. Copper(II) extraction by hydrophobic 2-, 3-, and 4-pyridyl ketoximes from sulphate solutions is not possible. However, addition of chloride ions to initial sulphate media enables metal removal. The oxime of 1-(2-pyridyl)tridecane-1-one was determined as the strongest extractant of the tested oximes, but metal stripping was impossible. For the rest of the studied extractants the stripping process could be done using water or diluted mineral acid.     

Equilibrium and Kinetics of Nickel Extraction with 2-Hydroxy-5-nonylbenzophenone Oxime

Abstract

The extraction of nickel with 2-hydroxy-5-nonylbenzophenone oxime (LIX 65N; HL) has been studied into chloroform solution. The extracted species was found to be NiL₂, and its extraction constant of 10^?5.90 was obtained. The rate of extraction of nickel has been found to be first-order in metal and ligand, and inverse first-order in hydrogen ion. The apparent rate constant of extraction (k') was 10^?7.40. These results support the hypothesis that the formation of the 1:1 complex in the aqueous phase is the rate-determining step. The rate constant of the formation of this complex was evaluated as 10^5.90.     

Facile and general method for preparation of (E)-4-hydroxy-2-alkenals

A facile one-pot synthesis of (E)-4-hydroxy-2-alkenals such as (E)-4-hydroxy-2-nonenal, (E)-4-hydroxy-2-heptenal, and (E)-4-hydroxy-2-hexenal was achieved from the corresponding (2E,4E)-2,4-alkadienals by reduction-oxygenation with molecular oxygen and triethylsilane in the presence of cobalt(II) porphyrin as a catalyst followed by treatment with trimethylphosphite.     

Synthesis and surface properties of chemodegradable anionic surfactants: Diastereomeric (2-n-alkyl-1,3-dioxan-5-yl) sulfates with monovalent counter-ions

Sodium, potassium and ammonium cis- and trans-(2-n-alkyl-1,3-dioxan-5-yl) sulfates 6–8 (alkyl: n-C₉H₁₉, 6a–8a, and n-C₁₁H₂₃, 6b–8b) were synthesized in a reaction of aliphatic aldehydes 1a,b with glycerol 2 followed by separation in high yields of individual geometric isomers of cis-and trans-2-n-alkyl-5-hydroxy-1,3-dioxanes, cis-3a,b and trans-3a,b, followed by sulfation with sulfur trioxide-pyridine complex, and finally neutralization with NaOH, KOH, and NH₄OH, respectively. Physical data of the compounds and some surface properties of 2-n-nonyl derivatives, such as critical micelle concentration (CMC), effectiveness of aqueous surface tension reduction (Π_CMC), surface excess concentration Γ_CMC, and the surface area demand per molecule (A_CMC), were determined. It was shown that the surface activity of these compounds is influenced both by their geometric structure and by the monovalent counter-ion.     

The catalytic effect of quaternary ammonium salt On the Extraction of Palladium(II) With 2-Hydroxy-5-Nonyi-Benzophenone Oxime(LIX 65N) In Heptane-Chloroform Solvents

Extraction of Pd(II) from acidic chloride media using 2-hydroxy-5-nonyi-benzophenone oxime (LIX 65N,KL) in heptane is 60% more rapid than that using chloroform under comparable conditions, as well as more complete, reflecting an eight-fold increase in the extraction constant. A further substantial increase in the ex traction rate was achieved using the quaternary ammonium sait, Aliquat 336S, without any change in the extraction constant. The extraction probaly occurs through rapid phase transfer of PdCl via ion pair extraction followed by formation of the chelate, PdL₂-, in the organic phase.     

Palladium Extraction from Nitric Acid Solutions by LIX 84 and LIX 860-I

ABSTRACT

The extraction of Pd(II) from weakly nitric acid solutions by LIX 84 (2-hydroxy-5-nonylacetophenone oxime) and LIX 860-I (5-dodecylsalicylaldoxime) dissolved in toluene has been studied and compared from the viewpoint of extraction equilibria. The effects of pH, nitrate ions and metal and extractant concentrations on the palladium distribution ratio have been quantified. The extraction rate of Pd(II) from this media is slow but the metal is quantitatively extracted by adding just the stoichiometric amount of the extractants. The experimental data have been treated graphically and numerically by means of the Letagrop-Distr program and can be explained by assuming the formation of the chelate PdL₂. Values of the extraction constants are also given.