Yu. I. Murinov

Determination of platinum metals by x-ray fluorescence, atomic emission and atomic absorption spectrometry after preconcentration with a polymeric thioether

Abstract A method for preconcentration of platinum metal based on their sorption by a polymeric thioether (—CH 2 S—) n is reported. The method is characterized by selectivity, high recovery and simplicity, and is suitable for a wide range of platinum metal concentrations; light non-ferrous metals do not interfere. The concentrate can be analyzed either directly or after rapid dissolution. The sorbent has a high capacity for platinum metals. X-ray fluorescence is suitable for determination of the metals in the concentrate after it has been compressed. This method provides a high precision in the determination of platinum metal ( s r = 0.02–0.04 for 250 μg −1 ). Electrothermal atomic absorption spectrometric methods can be applied to be concentrates with or without prior dissolution; these allow the determination of platinum metals even at the 1 ng ml −1 level in technical logical solutions and at the 0.1 ng g −1 level in solid products ( s r = 0.18). The concentrate can be also subjected to atomic emission spectrometry either with the inductively-coupled plasma after dissolution or with an arc discharge without dissolution. These methods allow the determination of platinum metal (0.1–100 μg ml −1 in technical solutions; the precision ( s r ) is 0.01–0.04 when the plasma is used.

Diene polymerizations with lanthanide coordination catalysts. II. The effects of catalytic system component types and polymerization conditions on molecular characteristics of 1,4-cis-Polybutadienes

Abstract Molecular inhomogeneity has been investigated for 1,4-cis-polybutadienes obtained with a lanthanide- containing catalytic system; some kinetic parameters have been estimated for polymerizations. Gel-permeation chromatography was chosen as the main method to find out the average molecular weights (MW) and molecular weight distributions (MWD). The catalyst composition has been shown to effect MW and MWD. The molecular characteristics are determined by both the catalyst composition and the polymerization conditions (reagent concentration, temperature). The broad MWD is considered a peculiarity of butadienes prepared with lanthanide- containing catalysts. The data obtained lead to the assumption that the distribution of the polymerization centres by reactivity is responsible for the broad MWD of the polybutadienes formed.

Fatty Imidazolines: A Novel Extractant for the Recovery of Palladium(II) from Hydrochloric Acid Solutions

The extraction of palladium(II) from hydrochloric acid solutions with a novel highly basic extractant, a mixture of homologous 1-[2-(alkanoylamino)ethyl]-2-alkyl-2-imidazolines (AAI) in toluene with 15% (v/v) of n-octanol was studied. Palladium(II) is rapidly and most effectively extracted with AAI hydrochloride at the low hydrochloric acid (chloride ions) concentration (up to 1 M) and can be completely separated from Fe(III), Cu(II), and Co(II). The palladium(II) extraction at the optimum acidity occurs via an anion-exchange mechanism with the formation of ionic associates (LH)2PdCl4 (K ex = (1.5 ± 0.2) · 104 at 0.5 M HCl) and is accompanied by the dimerization of palladium(II) in the organic phase with the formation of ionic associates (LH)2Pd2Cl6 (K dim = (3.9 ± 0.4) · 10−4 at 0.5 M HCl). The anion-exchange extraction of palladium(II) at the acidity of 0.5 M HCl is temperature independent in the range 20–49°C. Complete stripping of palladium(II) can be performed using a 5% solution of thiourea in 0.1 M HCl.

Extraction of hydrochloric and nitric acid with 1-{[2-(2,4-Dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]-methyl)-1H-1,2,4-triazole and (RS)-1-(4-Chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-yl-methyl)-pentan-3-ol

Extraction of hydrochloric and nitric acid with 1-{[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]-methyl}-1H-1,2,4-triazole (propiconazole) and hydrochloric acid with (RS)-1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-yl-methyl)-pentan-3-ol (tebuconazole) was studied. It is established that extraction of acids proceeds with the formation of monosolvates as an exothermic process. Effective extraction constants of acids are evaluated. By means of the IR and 1H NMR spectroscopy it was shown that the protonaccepting center of tebuconazole is N4 atom of the triazole ring.

Synthesis and Antitumor Activity of Complex Compounds of β-Glycyrrhizic Acid with Antitumor Drugs

A promising way of creating new highly effective drugs is the synthesis of molecular complexes which can protect parent substances from premature metabolic decay and provide for their controlled release. A premise in our approach was that the complex-forming agent must contain both a hydrophilic component (binding the main parent substance) and a hydrophobic component (responsible for the drug transport). Previously, we demonstrated that the molecular complexes of -glycyrrhizic acid (I) with prostaglandins and nonsteroidal antiinflammatory drugs are characterized by reduced toxicity and increased therapeutic breadth as compared to those of the components [1 – 6]. The main disadvantage of the well-known antitumor drugs 5-fluorouracil (II), ftorafur (III), rubomycin (IV), and their analogs is high toxicity [7 – 9]. We have synthesized a series of complex compounds involving acid I and drugs II – V in 1 : 1 ratio. The molecular complexes of I with fluorouracil were obtained in a water – ethanol medium at ~50°C, and the complexes with anthracycline antibiotics, in ethanol at room temperature. All compounds were characterized by IR and UV spectra. The UV spectra of complexes I II and I III exhibit intense absorption maxima in the region of 250 – 260 nm, related to the total absorption of conjugated ketone and fluoropyrimidine chromophore groups. The UV spectra of complexes I IV and I V display intense maxima in the region characteristic of aromatic chromophores (234 – 235 nm) and new maxima related to anthracycline groups (470 – 530 nm). As can be seen from the data in Table 1, the complexes of I with compounds II – IV are less toxic than the initial antitumor drugs. According to the results of preliminary experiments, the molecular complex of acid I with drug III exhibits antitumor action with respect to Pliss lymphosarcoma, melanoma B-16, and Guerin’s carcinoma (Table 2).

Extraction of palladium(II) from hydrochloric acid solutions with triacylated ethyleneamines

Extraction of palladium(II) from hydrochloric acid solutions with novel efficient extractants, triacylated ethyleneamines, was studied. The most effective extraction of palladium(II) was observed from 0.5–1 M HCl solutions. Extraction of palladium(II) from 1 M HCl solutions was found to occur through mixed (coordination and anion-exchange) mechanism. In the field of dominance of the anion-exchange mechanism of the extraction of palladium(II) with triacylated pentaethylenehexamine the concentration constant of palladium(II) extraction was calculated, and thermodynamic parameters of extraction were evaluated.

Propiconazole and Penconazole as Effective Extractants for Selective recovery and concentration of platinum(IV) and palladium(II) from hydrochloric acid solutions formed in leaching of spent aluminoplatinum and aluminopalladium catalysts

Selective recovery and concentration of platinum(IV) and palladium(II) from hydrochloric acid solutions of varied composition was studied using commercial reagents propiconazole and penconazole as extractants. The ranges of hydrochloric acid concentrations for effective extraction and highly selective separation of platinum metals from Al(III) and Ni(II) with propiconazole (toluene with 15 vol % n-decanol as deluent) and penconazole (chloroform) were determined. The conditions for 10-fold selective concentration of platinum metals with recovery of more than 99.9% of metal ions into the organic phase were found. The conditions for quantitative (>99%) stripping of platinum(IV) with a hydrochloric acid solution of thiourea and palladium(II) with ammonia solution were determined. The results obtained can be used for optimizing the modes of selective recovery of platinum(IV) and palladium(II) from hydrochloric acid solutions formed in leaching of alumina-supported platinum-rhenium, platinum-nickel, and palladium catalysts.

Extraction of gold(III), palladium(II), and platinum(IV) by 1-[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl]-1H-1,2,4-triazole from hydrochloric acid solutions

The extraction of gold(III), palladium(II), and platinum(IV) with 1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-1H-1,2,4-triazole from hydrochloric acid solutions into toluene has been studied. The extraction follows the anion-exchange mechanism. The concentration constants and thermodynamic parameters of the extraction reaction have been calculated. The reagent is proposed for use in the extraction of the sum of precious metals.

Isolation and GC-MS determination of flavonoids from Glycyrrhiza glabra root

Components of the ethylacetate extract of Glycyrrhiza glabra root were separated based on their acid-base properties. The major components of the fraction soluble in aqueous NaOH were identified by GC-MS as glabridin, the principal component of the ethylacetate extract of licorice root (Glycyrrhiza glabra L.), 4-O-methylglabridin, and hispaglabridin B. The isoflavene glabrin was identified in addition to the isoflavan derivatives.

Physicochemical Properties and Pharmacological Activity of Mn(II), Fe(II), Co(II), Cu(II), AND Zn(II) Gluconates

The well-known antitumor drugs suppress the immune system to different degrees [1]. It is therefore important to find substances possessing, in addition to antitumor activity, immunotropic properties. Of special interest in this respect are compounds of d-elements, an imbalance of which is known to accompany various pathological processes, including tumor growth [2 – 4]. The coordination compounds of these metals possess both immunomodulant properties [5 – 7] and cytotoxic activity [8 – 10]. It was reported that 3d-metal gluconates are effective correctors in some pathological states [11 – 14]. For this reason, we have synthesized gluconates of Mn, Fe, Co, Cu, and Zn (compounds I – V, respectively), determined some physicochemical properties of these compounds, and evaluated their cytotoxic and immunotropic activity. The compositions of gluconates I – V correspond to the general formula M(C6H11O7)2 2H2O, where M = Mn(II), Fe(II), Co(II), Cu(II), and Zn(II). The synthesized compounds were characterized by spectroscopic methods, thermogravimetric (TGA) and elemental analyses, and conductivity measurements in aqueous solutions. The IR absorption spectra of the synthesized compounds were analyzed in comparison to the spectra of the initial reagent, gluconic acid (VI), and the reference drug – calcium gluconate (VII). The IR spectra of metal gluconates display a strong absorption band at 1600 – 1588 cm – 1 and a medium-intensity band 1400 – 1420 cm – , corresponding to the antisymmetric and symmetric stretching vibrations of the carboxylate ion, respectively. In contrast, the spectrum of acid VI exhibits an absorption band at 1740 cm – , assigned to C=O of the COOH group. The formation of metal gluconates is always accompanied by almost complete vanishing of the absorption band at 1190 cm – 1 belonging to bending vibrations of the carboxy (C–O) group [15]. The absorption bands of bending vibrations of the secondary hydroxy groups OH, which are observed at 1220 – 1300 cm – 1 in the spectrum of calcium gluconate, shift to 1350 – 1400 cm – 1 in the spectra of compounds I – V. Significant differences between the IR spectra of gluconates and the spectra of gluconic acid and calcium gluconate are also observed for C–O of the secondary carboxy groups in the region of 1080 – 1135 cm – 1 and for their skeletal vibrations at 1000 – 1080 cm – 1 (Fig. 1). These distinctions indicate that these groups are involved in the formation of donor – acceptor groups with d-metal ions. Larsson [16] explained the observed character of absorption in this region by the formation of a chelate ring upon the complexation of d-elements with oxy acids. The results of C NMR measurements showed (Table 1) that this binding is mediated by the oxygen atom of a hydroxy group at the third carbon atom. This conclusion is confirmed by stereochemical considerations. Calculations by the AMPAK program using the AM-1 method, as well as the published data [17], indicate that the structure of molecule VI contains a fragment convenient for the formation of a six-member chelate cycle involving oxygen atoms of the carboxy group and the hydroxy group at the third carbon atom.