Aspartic acid in a new role: Synthesis and application of a pH-responsive cyclopolymer containing residues of the amino acid

The reaction between diallylamine and dimethyl maleate afforded the Michael addition product dimethyl N,N-diallylaspartate [(CH₂CH–CH₂)₂NCH(CO₂Me)CH₂CO₂Me] I, which upon treatment with dry HCl and ester hydrolysis with aqueous HCl gave its hydrochloride salt [(CH₂CH–CH₂)₂NH⁺CH(CO₂Me)CH₂CO₂Me Cl⁻] II and N,N-diallylaspartic acid hydrochloride [(CH₂CH–CH₂)₂NH⁺CH(CO₂H)CH₂CO₂H Cl⁻] III, respectively. The new monomers II and III underwent cyclopolymerization to give, respectively, cationic polyelectrolytes (CPEs) poly(II) and poly(III). Under the influence of pH, triprotic acid (+) poly(III) was equilibrated to water-insoluble diprotic polyzwitterionic acid (±) IV, water-soluble monoprotic poly(zwitterion–anion) (± −) V, and its conjugate base polydianion (=) VI. The protonation constants of the carboxyl group and trivalent nitrogen in VI have been determined. A 20-ppm concentration of IV is effective in inhibiting the precipitation of CaSO₄ from its supersaturated solution with an ≈ 100% scale inhibition efficiency for a duration of 50 h at 40 °C. The aqueous two-phase systems (ATPSs) of VI and polyoxyethylene have been studied. The transformation of water-soluble VI to insoluble IV makes it a recycling ATPS as it can be recycled by precipitation at a lower pH.     

Synthesis of a terpolymer and a tetrapolymer using monomers of diallylamine salts and SO<Subscript>2</Subscript> and their application as antiscalants

An aqueous solution of diallylammonium salts (CH₂ = CHCH₂)₂NH⁺(CH₂)₃A^? having A^? as: CO₂ ^? (I), PO₃H₂ Cl^? (II) and SO₃ ^? (III) in 1:1:1 mol ratio underwent ammonium persulfate-initiated ter cyclopolymerization to yield pH-responsive zwitterionic polymer IV with random placements of the monomers in the same ratio. During dialysis, PO₃H₂Cl^? of the incorporated monomer units of II upon depletion of HCl became PO₃H^?. Likewise, azobisisobutyronitrile-initiated cyclopolymerization of I, II, III, and SO₂ in a mole ratio of 1:1:1:3 provided pH-responsive tetrapolymer V in over 90 % yield with random and alternative placements of I–III and SO₂ units, respectively, in the same ratio as the feed. Polyzwitterions (PZs) IV and V were insoluble in salt-free water but soluble in the presence of salts. The critical salt concentrations required to promote water solubility of PZ IV were determined to be 0.356 M NaCl, 0.237 M NaBr and 0.128 M NaI, whereas for PZ V the corresponding values were found to be 2.25, 1.26 and 0.862 M, respectively. PZs IV and V were converted into anionic polyelectrolytes VI and VII upon basification with NaOH. The viscosity and antiscalant behaviors of VI and VII were examined. The polymers demonstrated remarkable scale inhibition efficacies; at a dose of 10 ppm, both IV (+NaOH) and V (+NaOH) delayed the precipitation of CaSO₄ from its supersaturated solution up to 920 and over 4000 min, respectively. For a small concentration of 5 ppm of polymer V, a scale inhibition of 100 % over 100 min verified it to be a potential effective antiscalant additive in reverse osmosis plants.     

New members in the [Mn10] supertetrahedron family

Two manganese complexes, [Mn^II₄Mn^III₆Cl₄(CH₃OCH₂CH₂O)₁₂ O₄][Mn^II₃Ti^IVCl₆(CH₃OCH₂CH₂O)₆] (1) and [Mn^II₄Mn^III₆Cl₄(CH₃OCH₂CH₂O)₁₂O₄] [Mn₄^II Cl₁₀(CH₃OCH₂CH₂OH)₄]∙0.5CH₃OCH₂CH₂OH, (2) have been obtained and characterized by single-crystal X-ray diffraction. Both structures consist of the decametallic dicationic [Mn^II₄Mn^III₆Cl₄(CH₃OCH₂CH₂O)₁₂O₄]^2 + core constructed by four vertex-sharing [Mn^III₃Mn^IIO]^9 + tetrahedra. Also, these compounds contain the different tetrametallic dianions: [Mn^II₃Ti^IVCl₆(CH₃OCH₂CH₂O)₆]^2 − (in complex 1) and [Mn₄^IICl₁₀(CH₃OCH₂CH₂OH)₄]^2 − (in complex 2). Magnetic dc and ac susceptibility measurements for compound (1) show that the dicationic decanuclear magnetic cluster possesses an S = 12 ± 1 spin ground-state.     

Metal Induced Decarboxylation of Aliphatic Free Radicals. I. Kinetics of the Reactions of Copper(I) and Copper(II) Ions with the 2-Methyl-2-Carboxylicacid-Propyl Free Radical in Aqueous Solutions. A Pulse Radiolysis Study

CH₂C(CH₃)₂CO₂H free radicals react with Cu²⁺_aq to form Cu^III-CH₂C(CH₃)₂CO₂H²⁺_aq, which probably is rapidly transformed into intermediate I. This intermediate decomposes into Cu⁺_aq + CO₂ + CH₂=C(CH₃)₂. This is the first system in which a metal ion induced β-carboxyl elimination reaction was observed. ·CH₂C(CH₃)₂CO₂H free radicals react with Cu^III-CH₂C(CH₃)₂CO₂H²⁺_aq to form Cu²⁺_aq and a mixture of (-CH₂C(CH₃)₂CO₂H)₂, (CH₃)₃CCO₂H, and HOCH₂C(CH₃)₂CO₂H. CH₂C(CH₃)₂CO₂H reacts with Cu⁺_aq to form Cu^II-CH₂C(CH₃)₂CO₂H⁺_aq. The latter intermediate decomposes both via homolysis and by a reaction with Cu²⁺_aq to form 2Cu²⁺_aq + (CH₃)₃CCO₂H. The spectra of the intermediates and the kinetics of reaction are reported.     

Metallkomplexe mit biologisch wichtigen Liganden. CXXIII. Darstellung von Isophthaloyl‐ und Terephthaloyl‐di‐[(β,γ,δ)‐amino‐α‐aminocarboxylat]‐verbrückten zweikernigen Ruthenium‐, Rhodium‐ und Iridium‐Halbsandwich‐Komplexen

The reaction of the Cu(II) bis N,O‐chelate‐complexes of L‐2,4‐diaminobutyric acid, L‐ornithine and L‐lysine {Cu[H₂N–CH(COO)(CH₂)_nNH₃]₂}²⁺(Cl^–)₂ (n = 2–4) with terephthaloyl dichloride or isophthaloyl dichloride gives the polymeric complexes {‐OC–C₆H₄–CO–NH–(CH₂)_n–CH(nh₂)(COO)Cu(OOC)(NH₂)CH–CH₂)_n–NH‐}_x 1 – 5 . From these the metal can be removed by precipitation of Cu(II) with H₂S. The liberated ω,ω′‐N,N′‐diterephthaloyl (or iso‐phthaloyl)‐diaminoacids 6 – 10 react with [Ru(cymene)Cl₂]₂, [Ru(C₆Me₆)Cl₂]₂, [Cp*RhCl₂]₂ or [Cp*IrCl₂]₂ to the ligand bridged bis‐amino acidate complexes [L_n(Cl)M–(OOC)(NH₂)CH–(CH₂)_nNH–CO]₂–C₆H₄ 11 – 14 .     

Effect of electron density on the catalysts for copolymerization of propylene oxide and CO<Subscript>2</Subscript>

Copolymerization of propylene oxide and carbon dioxide (CO₂) has been studied using different R-salophenCoOBzF₅ (OBzF₅ = pentaflorobenzoate, R = CH₃, H, Cl, Cl₂) based catalysts. The central moiety of the catalysts R-salophenCoOBzF₅ has been kept the same and effect of the catalyst electron density on the copolymerization reaction has been studied. It has been observed that introduction of an electron withdrawing group (like Cl, Cl₂) on the o-phenylenediamine backbone moiety of the catalyst makes it more selective for poly(propylene carbonate) synthesis. On the other hand, introduction of an electron donating group (like CH₃) makes the catalyst selective for cyclic carbonate conversion. The effect of different type of co-catalysts has also been investigated using tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, [PPN]⁺Cl^? ([PPN]⁺ = bis(triphenylphosphine)iminium), DMAP and tetrabutyl ammonium bromide.     

Synthesis and application of a cyclopolymer bearing a propylphosphonic acid and a propylcarboxylic acid pendants in the same repeating unit

Diallyl[3-(diethoxyphosphoryl)propyl](3-ethoxycarbonylpropyl)ammonium chloride [ (CH₂CH=CH₂)₂N⁺{(CH₂)₃PO₃Et₂} {(CH₂)₃CO₂Et} Cl^?], a new diallyl quaternary ammonium salt, has been cyclopolymerized to its cationic polyelectrolyte having pyrrolidine rings embedded in the polymer backbone. The polymer represents the first example of a cyclopolymer in which each repeating unit contains a propylphosphonate as well as a propylcarboxylate pendant. The hydrolysis of one, two or all the three-ester groups in the polymer afforded a series of pH-responsive macromolecules having identical degree of polymerization, which permitted a meaningful comparison of their solution behaviors. Apparent pK _as of the triprotic repeating unit have been determined to be 2.52, 5.32 for 9.02 for the functionalities –PO₃H₂, ?CO₂H, and –PO₃H^?, respectively. The completely hydrolyzed polymer containing PO₃H₂ and CO₂H groups demonstrated remarkable antiscalant behavior; at a concentration of 10 ppm, it inhibited the scaling of CaSO₄ from its supersaturated solution with an inhibition efficiency of 100 % for over 500 min. The polymer may thus be exploited as an antiscalant in reverse osmosis plants.     

Chemometric analysis of selective polyphenolic groups in Asparagus racemosus (Shatavar) root extracts by traditional and supercritical fluid (CO2) based extractions

ABSTRACT

Asparagus racemosus root extracts were prepared by supercritical fluid (CO₂), soxhlet, and maceration-based methods also with various pretreatments. Thereafter, these root extracts were analyzed by High-Performance Liquid Chromatography, along with the chemometric study of the disparate phenolic groups. Among these, supercritical fluid (CO₂) based extract has a larger number of polar compounds and the antioxidant activity (98.54 ± 0.22 µM Trolox equivalent mg^?1). It also has the best cell viability (94.37 ± 1.12%) and insulin release (0.82 ± 1.12 ng mL^?1) on β-pancreatic RINm-5F cells whereas, the best extractive yield (75.80 ± 3.44% w/w) was observed for pretreated aqueous soxhlet-based extract.     

Electrocarboxylation of chloroacetonitrile by a Cobalt(I) complex of terpyridine

The electrocarboxylation of chloroacetonitrile (NC–CH₂–ClRCl) mediated by [Co^IIL₂]²⁺ (L = terpyridine) was investigated by cyclic voltammetry. Electrochemical studies under argon atmosphere showed that the monoelectronic reduction of [Co^IIL₂]²⁺ yielded a Cobalt(I) complex which after the loss of a terpyridine ligand reacted with chloroacetonitrile. The oxidative addition of chloroacetonitrile on [Co^IL]⁺ gave an alkylCobalt(III) complex [R–Co^IIIL]²⁺ which was reduced into an alkylCobalt(II) complex, highly unstable and decomposed into an alkyl anion and a Cobalt(II) complex. Under carbon dioxide atmosphere, Cobalt(I) complex was shown to be unreactive towards CO₂ but CO₂ insertion was observed in the alkylCobalt(III) complex [R–Co^IIIL] ²⁺ giving probably a CO₂ adduct [R–Co^IIIL(CO₂)]²⁺. This adduct presented a strong adsorption at the carbon electrode and was reduced at potential less cathodic than the one of alkylCobalt(III) complex. After reduction, the carboxylate RCO₂⁻ (NC–CH₂–CO₂⁻) was released and a catalytic bielectronic carboxylation of chloroacetonitrile took place. Controlled potential electrolyses confirmed the catalytic process and gave for cyanoacetic acid faradic yields up to 60% under low overpotential conditions.     

Magnetic behavior of polycarbosilazane ?FeII, ?FeIII and mixed‐valence ?FeII–III chloride metallopolymers

Fe^II, Fe^III and mixed‐valence Fe^II–III chlorides were reacted with poly[N,N′‐bis(dimethylsilyl)ethylenedi‐ amine], [? Si(CH₃)₂NHCH₂CH₂NH? ]_n, to form the corresponding Fe‐polycarbosilazane macromolecular complexes. The average chain–chain spacing in these materials was estimated from X‐ray diffraction data and found to be 6.94, 7.29, 7.30 and 7.45 Å in metal‐free and Fe^II? , Fe^III? and Fe^II–III‐containing polycarbosilazanes, respectively. This demonstrates that Fe^II, Fe^III and Fe^II–III chlorides are encapsulated between the polycarbosilazane chains. The chain–chain expansions in the divalent Fe^II and trivalent Fe^III chloride macromolecular complexes are comparable, but less than that in the Fe^II–III chloride analog, which suggests that different chain–chain packings exist in the mixed‐valence macromolecular complex. The magnetic properties of the resulting complexes were investigated by measuring the magnetization in magnetic fields up to 8 kOe and in the temperature range from liquid nitrogen temperature to room temperature. Copyright © 2007 Society of Chemical Industry     

Synthesis of stimuli-responsive ionic cyclopolymers in search of phosphorous-free antiscalants

Ammonium persulfate-initiated cyclopolymerization of maleic acid (HO₂CC=CCO₂H) (MA) with diallylamine (–NR₂, R = CH₂ = CH-CH₂) derivatives (DADs): R₂NH⁺CH₂CO₂⁻ ( I ), R₂NCH₂CO₂⁻Na⁺ ( II ), R₂NCH₂CO₂Et ( III ), R₂NH⁺(CH₂)₃CO₂⁻ ( IV ), R₂N(CH₂)₃CO₂Et ( V ), R₂NH⁺(CH₂)₃SO₃⁻ ( VI ) and R₂N(CH₂)₃SO₃⁻Na⁺ ( VII ) gave a series of new pH-responsive alternate copolymers: –[(DAD-alt-MA)]_n– VIII - XIV , respectively. Homopolymers XV and XVI of the corresponding monomers IV and V ·HCl were also synthesized. The evaluation of the synthesized polymers as potential antiscalants in reverse osmosis (RO) plants was examined. An effective scale inhibitor must arrest the formation of scale for a residence time (≈15 min) of feed water in the RO chamber. R₂NH⁺(CH₂)₃CO₂⁻ ( IV )-alt-MA copolymer XI at a concentration of 5 ppm imparted 99% scale inhibition for 360 min, while at 2.5 and 1 ppm concentrations, the CaSO₄ scale inhibitions were found to be 99% and ≈ 100% during 120 and 20 min, respectively, at 40°C. Homopolymers XV and XVI , at a 20-ppm concentration, demonstrated ≈ 95% efficiency in inhibiting mild steel corrosion in 1 M HCl. In some important oilfield applications, requirement of simultaneous scale and corrosion inhibition make these polymers potential candidates for desalination and oilfield applications.     

Studies on the Recovery of Uranium from Phosphoric Acid Medium Using Synergistic Mixture of 2-Ethyl Hexyl Hydrogen 2-Ethyl Hexyl Phosphonate and Octyl(phenyl)-N,N-diisobutyl Carbamoyl Methyl Phosphine Oxide

Abstract

This paper describes the extraction of uranium from aqueous phosphoric acid medium using 2-ethyl hexyl hydrogen 2-ethyl hexyl phosphonate (PC88A) and octyl (phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) individually as well as their synergistic mixture in different diluents. The extraction parameters such as variation in concentration of either of the extractants, concentration of H₃PO₄ and uranium in the aqueous phase are investigated to optimize the extraction conditions. Results indicate that the synergistic mixture, 0.9 M PC88A + 0.1 M CMPO in xylene, can be used for the extraction of uranium from the phosphoric acid medium. The loaded uranium from the synergistic organic phase can be stripped using 0.5 M solution of (NH₄)₂CO₃. This synergistic mixture is used to recover uranium from a typical wet process phosphoric acid sample and the recovery is found to be better than 90%.     

Ionic Liquids Promoted the C-Acylation of Acetals in Solvent-free Conditions

The synthesis of a series of fourteen 4-alkoxy-1,1,1-trihalo-3-alken-2-ones (2,3) [CX₃COC(R²)=C(R¹)OMe, where X = Cl, F; R¹/R² = Me/H, Bu/H, i-Bu/H, Ph/H, Thien-2-yl/H, –(CH₂)₄–, –CH(CH₂)₄CH(CH₂)₂–] from the acylation reactions of acetals (1) with trichloroacetyl chloride or trifluoroacetic anhydride in the presence of equimolar amounts of pyridine and imidazolium based ionic liquid ([BMIM][BF₄] or [BMIM][PF₆]) is reported. The reaction time, yields and IL recyclation are also investigated and this method showed advantages over the methods described in the literature.     

Studies on the Separation and Recovery of Uranium from Phosphoric Acid Medium Using a Synergistic Mixture of (2-Ethylhexyl)phosphonic Acid Mono 2-Ethyl Hexyl Ester (PC-88A) and Tri-n-octylphosphine Oxide (TOPO)

This paper deals with studies on the extraction of uranium(VI) from phosphoric acid medium using (2-ethylhexyl)phosphonic acid mono 2-ethylhexyl ester and tri-n-octylphosphine oxide individually as well as from their synergistic mixture. Different extraction parameters were investigated. With an increase in phosphoric acid concentration in the aqueous phase, the distribution ratio (Du) was found to decrease in all the cases. Synergism was observed when a mixture of PC-88A and TOPO was used. The synergistic mixture in the mole ratio of 4:1 (1.80 M PC-88A: 0.45 M TOPO) in xylene was found to be most suitable for uranium extraction. Among the various strip liquors used, 5% (w/v) solution of (NH₄)₂CO₃ was found to be the most suitable. Using a mixture of 1.8 M PC-88A and 0.45 M TOPO as the extractant system and 0.5 M ammonium carbonate as the stripping agent, uranium recovery was found to be better than 97% ± 3% in multiple contacts, (n = 2) from actual Davies Gray Waste while in case of wet phosphoric acid more than 52% ± 3% (n = 3) only could be recovered where n is the number of contacts.     

Ionic polymers with expanded π‐conjugation systems derived from through‐space interaction in piperazinium and homopiperazinium rings

Reactions of N‐(2,4‐dinitrophenyl)‐4‐arylpyridinium chlorides (aryl (Ar) = phenyl and 4‐biphenyl) with piperazine or homopiperazine caused opening of the pyridinium ring and yielded polymers that consisted of 5‐piperazinium‐3‐arylpenta‐2,4‐dienylideneammonium chloride (? N(CH₂CH₂)₂N⁺ (Cl^?)?CH? CH?C(Ar)? CH?CH? ) or 5‐homopiperazinium‐3‐arylpenta‐2,4‐dienylideneammonium chloride (? N(CH₂CH₂CH₂)(CH₂CH₂)N⁺ (Cl^?)?CH? CH?C(Ar)? CH?CH? ) units. ¹H NMR spectral analysis suggested that the π‐electrons of the penta‐2,4‐dienylideneammonium group of the polymers were delocalized. UV‐visible spectral measurements revealed that the π‐conjugation system expanded along the polymer chains because of the orbital interaction between electrons of the two nitrogen atoms of the piperazinium and homopiperazinium rings. However, the π‐conjugation length depended on the distance between the two nitrogen atoms; that is, the polymers containing the piperazinium ring had a longer π‐conjugation length than those containing the homopiperazinium ring. Conversion of the piperazinium and homopiperazinium rings from the boat to the chair form led to a decrease in the π‐conjugation length. The surface of pellets that were molded from the polymers exhibited metallic luster, and these polymers underwent electrochemical oxidation in solution. Copyright © 2010 Society of Chemical Industry     

Atomic and Molecular Adsorption on Re(0001)

Using periodic, self-consistent density functional theory calculations, the adsorption of several atomic (H, S, N, O and C) and molecular (CO₂, N₂, NH₃, HCN, CO and NO) species and molecular fragments (NH₂, NH, CN, CNH₂, HNO, NOH, CH₃, CH₂, CH and OH) on the (0001) facet of rhenium at a coverage of 0.25 ML has been studied. Preferred binding sites with their corresponding binding energy and deformation energy of the surface, as well as an estimated diffusion barrier of each species have been determined. Atomic species and molecular fragments tend to bind to threefold sites, whereas molecular species tend to bind to top sites. The binding strength, with respect to the corresponding gas phase species and in increasing order for all species studied, is: CO₂ < N₂ < NH₃ < CO < CH₃ < HCN < NO < H < NH₂ < OH < CH₂ < CNH₂ < CN < HNO < NH < NOH < S < N < O < CH < C. The vibrational frequencies of all species in their most energetically favorable adsorbed configuration have been calculated. Finally, the thermochemistry of adsorption and decomposition of NO, NO + H, NH₃, N₂, CO₂, CO and CH₄ on Re(0001) has been analyzed.     

Solid‐Liquid Extraction of Terbium from Phosphoric Acid Medium using Bifunctional Phosphinic Acid Resin,Tulsion CH‐96

Solid‐liquid extraction of terbium from phosphoric acid medium has been studied using the commercially available macroporous bifunctional phosphinic acid resin, Tulsion CH‐96. The parameters studied include equilibration time, acid concentration, amount of resin, metal concentration, temperature, loading, elution, regeneration, and recycling. In the wide range of phosphoric acid concentration 0.01–7.8 M the percent extraction of terbium decreases from 98.9% at 0.01 M to 16.0% at 1 M due to an ion‐exchange mechanism and increases to 36% at 7.8 M due to a coordination mechanism. The percent extraction increases with an increase in weight of the resin from 2.7% at 0.05 g to 80.7% at 1.2 g. Under the studied experimental conditions, the loading of Tulsion CH‐96 for terbium was determined to be 3.52 mg per gram of resin. The percent extraction of terbium increases with the increase in temperature, indicating the endothermic nature of the extraction process. Screening of various eluants suggested 1 M (NH₄)₂CO₃ as the best with an efficiency of 99.8%. The extraction behavior of commonly associated metals with terbium such as yttrium, holmium, erbium, dysprosium, ytterbium, and lutetium has been studied as a function of phosphoric acid concentration to determine the separation factors and possible separation.     

Hydrothermal Synthesis and Characterization of Trimethyltin(IV) Derivatives with 2-Carboxyethylphosphonic and Benzylphosphonic acid: X-ray Crystal Structures of 2D Network Polymers

Two organotin(IV) derivatives, {[(CH₃)₃Sn]₆·[O₃P(CH₂)₂CO₂]₂·3H₂O} _n 1 and {[(CH₃)₂Sn]₄·[O₃PCH₂Ph]₄} _n 2, were synthesized by the reaction of trimethyltin(IV) chloride, 2-carboxyethylphosphonic acid and benzylphosphonic acid, respectively. Characterization of complexes 1 and 2 were achieved using elemental analysis, IR, TGA, NMR (¹H, ¹³C, ³¹P and ¹¹⁹Sn) spectroscopy and X-ray crystallography diffraction analysis. X-ray characterization show that complexes 1 and 2 are 2D network structures.     

Synthesis of a novel zwitterionic bisphosphonate cyclopolymer containing residues of alendronic acid

The reaction of 4-(diallylammonio)butanoate, H₃PO₃ and PCl₃ in CH₃SO₃H created water-insoluble 4-diallylamino-1-hydroxybutylidene-1,1-bisphosphonic acid I, a novel monomer that contained residues of the osteoporosis drug alendronic acid. Monomer (±) I, a zwitterionic tetraprotic acid, in the presence of 2 equivs. NaOH(aq) and the initiator ammonium persulfate, underwent cyclopolymerization to yield water-soluble poly(zwitterion–dianion) (± =) II. Under the influence of pH, II was equilibrated to water-soluble poly(zwitterion–trianion) (± ≡) III, polytetraanion (= =) IV, poly(zwitterion–anion) (± −) V, cationic polyelectrolyte (+) VI and water-insoluble polyzwitterion (±) VII. The solution properties of backbone charges were investigated, and protonation constants of several centers in IV were determined. Polymers that contained residues of alendronic acid should have applications in various fields, including the field of medicine.     

Solvent Extraction of Au(III) by the Chloride Salt of the Amine Alamine 304 and Its Application to a Solid Supported Liquid Membrane System

Abstract

The extraction of Au(III) by the chloride salt of the amine Alamine 304 (R₃NH⁺Cl^?) in xylene from hydrochloric acid solutions has been investigated. The analysis of metal distribution data by numerical calculations suggested the formation of the species R₃NH⁺AuCl₄ ^? in the organic phase with formation constant log K _ext = 5.44. The results obtained on Au(III) distribution have been implemented in a solid‐supported liquid membrane system, where in NaSCN solutions were found to be the most effective to strip the metal from the organic solution. Influence of membrane composition, metal concentration on gold transport, and the selectivity of the system have also been studied.