Extraction of palladium with acyclic analogs of thiacalix[4]arenes from nitric acid solutions

p-tert-Butylcalix[4]arene was compared with its acyclic analogs in palladium extraction from nitric acid solutions as mononuclear and poly(bi)nuclear complexes with participation of protonated molecules of podands and macrocycle. The extraction ability of podands is similar to that of macrocycle because of the same character of complexation (Pd: S = 1: 1) without formation of new chelates and lower than that of monodentate analog owing to formation of a square complex (Pd: S = 1: 2).     

Extraction of heterometal ruthenium(II) complexes by diphenyl(dibutylcarbamoylmethyl)phosphine oxide from nitrate-nitrite solutions

The synergistic extraction of [RuNO(NO₂)₄OH]^2? by diphenyl(dibutylcarbamoylmethyl)phosphine oxide (L) in the presence of nonprecious metal cations (M²⁺) is studied; the extraction occurs on the account of the formation of heterometal complexes [RuNO(NO₂)₄OHML_m] (M = Zn, Cu, Co, Ni) due to the addition of M²⁺ to ruthenium through the oxygen atoms of the OH and NO₂ groups and the bidentate coordination of L to M²⁺. The extraction constants for Ru/M complexes and ML_n(NO₃)₂ are determined. The variation in the extraction constants with changing M (Co, Zn, Cu > Ni) does not agree with the Irwing-Williams row, unlike the extraction with monodentate PO-containing extractants (Zn > Cu > Co > Ni). The feasibility of ruthenium extraction in the form of Ru/M complexes from complex nitrate-nitrite solutions is demonstrated.     

Conversion of N-acetylneuraminic acid glycosyl chloride into dibenzyl glycosyl phosphate: O-glycosylation in the absence of a promoter

Readily accessible N-acetylneuraminic acid (Neu5Ac) glycosyl chloride, which was regarded to be a poor glycosyl donor, was shown to react with dibenzyl phosphoric acid salts in the absence of glycosylation promoters to give the corresponding -Neu5Ac dibenzyl glycosyl phosphate in high yield.     

Complexing and extraction of palladium(II) by <Emphasis Type="Italic">n</Emphasis>-alkyl(tolyl)thiamethylcalix[4]arenes from chloride solutions

Complexing [PdCl₄]^2? with calix[4]arenes (L) functionalized by CH₂SR (R = Me (1), n-Bu (2), or p-Tol (3)) in their upper rims has been studied in toluene and CCl₄. The stoichiometry of the extracted palladium species (PdCl₂) _n L, where n = 1 or 2 is established by spectroscopic methods (NMR spectroscopy, UV/Vis spectrophotometry, atomic absorption) and extraction. For slow coordinative extraction, the concentration constants of complex formation and extraction from chloride solutions are determined using the coupled equilibria method. The kinetic and thermodynamic laws of extraction coincide, and their parameters increase in the following row of the substituents at the sulfur atom: p-Tol < Bu < Me.     

Synthesis of 3,6-di-O-methyl-β-d-glucopyranose conjugates

3,6-Di-O-methyl-β-d-glucopyranose neoglycoconjugates with bovine serum albumine and poly(acrylamide) carrier were obtained, which differ in the aglycon nature, linking pattern, and substitution degree.     

Method for the preparation of 3β-chloro(bromo)-substituted steroids from the corresponding methyl ethers

Conclusions A stereospecific method was developed for obtaining 3-chloro(bromo)-substituted steroids by treating the appropriate methyl ethers with phosphorus pentahalide derivatives and BF₃·etherate.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2825–2827, December, 1970.     

Extraction-back extraction preconcentration in the system based on p-alkylaniline and oil sulfides for determining platinum-group metals and gold by inductively coupled plasma atomic emission spectrometry

A procedure is developed for determining all platinum-group metals (PGM) and gold (10⁻⁷ to 10⁻⁴%). It includes the autoclave digestion of samples with the transfer of metals into a hydrochloric acid medium without losing osmium and ruthenium, group 10- to 20-fold extraction preconcentration of precious metals with the removal of matrix interfering elements to a factor of 10⁵–10⁶, and the analysis of the group back extract of PGM and gold by ICP AES. A method is proposed for the quantitative back extraction of all PGM and gold from a group extract in two steps of consecutively washing the extract with ammonia solutions and thiourea. The procedure is tested on seven GSO samples and technological objects. It is shown that ICP MS can be used for the analysis of group back extracts of PGM and gold.