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The rate of acid catalyzed hydrolysis of pentachlorophenol (PCP) can be described by the general equation-d[PCP]/dt = kexp[PCP]. The experimental pseudo-first order rate constant generally increases with increase of the H+ concentration, but this dependence has a complex character. A kinetic model, which takes into account the pKa of PCP and a combination of catalyzed and uncatalyzed reactions, was suggested. This model is consistent with experimental results in the whole range of pH studied.

The influence of di-n-butyl phosphoric acid (HDBP) upon extraction of uranium(VI) by tri-n-butyl phosphate (TBP) from 0.5--3.0 M nitric acid solutions has been studied. It has been shown that the uranium(VI) distribution coefficient D{sub U} for extraction by 1.1 M TBP in tri-decane or xylene is increased when HDBP is present in the organic phase. For iso-molar solutions of (TBP + HDBP) with a total concentration of 0.36 M, and Uranium(VI) aqueous concentration up to 10--20 g/l, a maximum value of D{sub U} is observed when TBP/HDBP = 1; for higher U(VI) concentration the maximum gradually disappears, with D{sub U} growing monotonically with the HDBP content in the organic phase. Uranium(VI) absorption spectra for 1.1 M TBP in tri-decane or xylene, containing HDBP, provide evidence for the formation of compounds, of which composition is intermediate between uranyl nitrate--TBP disolvate and the U(VI)--HDBP complex. It is proposed that these intermediate compounds are UO{sub 2}(NO{sub 3}){sub 2}HDBP.TBP and UO{sub 2}(NO{sub 3}){sub 2}(HDBP){sub 2}.

A general and simple preparative method for the synthesis of α-hydroxyalky(benzyl)furazan and -furoxan derivatives is proposed, The method involves reduction of acyl or ethoxycarbonyl substituents in these heterocyclic compounds with NaBH4 in ethanol. Based on the alcohols thus prepared, a number of previously unknown functional derivatives (α-nitroxyalkyl-α-haloalkyl-, and α-azidoalkylfurazans and -furoxans) have been synthesized.

The use of electromembrane technology for aluminium plant waste water treatment and for a new type of acidic catalyst synthesis has been studied. To recycle the exhaust gas desulphurization solution of an aluminium plant whose main components were Na2SO4 and NaF the four-compartment electrodialyzer with one cation exchange and two anion exchange membranes was used. Desalination and recycling of this solution with simultaneous formation of caustic soda and AlF3 used in the main process is an example of waste water recycling. For tungstic heteropoly acid synthesis from sodium tungstate and phosphate the traditional two-compartment electrodialyzer with a cation exchange membrane was used. Electrochemical acidification of substrates in the anode compartment of the electrodialyzer with simultaneous removal of sodium ions through the membrane permits a quantitative yield of the product and excludes waste water formation.

Electrochemical dechlorination of 1,2,3,5-tetrachlorobenzene in methanol and chlorobenzene in dimethylsulfoxide with tetraalkylammonium salts as supporting electrolytes was carried out. The extent of dechlorination depends significantly on the electrode composition.

We have studied the electromembrane method for obtaining H3PW12O40. using31P,183W and17O NMR, we have studied the conversions of isopoly-and heteropolytungstates over a broad pH range. Depending on the acidity of the medium and the form of the isopolytungstate, we propose two schemes for reaction of isopolytungstates with phosphate ions during formation of H3PW12O40.

Ionexchange and electrochemical methods of preparing the heteropolyacid H3PW12O40 are studied. Conditions are found for preparing H3PW12O40 in quantitative yield using electrodialysis without ether extraction.

An electromembrane method has been proposed for the synthesis of H6P2W21O71, its resistance to heat in the solid state has been studied, and the Hammett acidity functions of concentrated aqueous solutions measured.

1. The authors have measured the electrical conductivity of heteropoly acids (HPA.) based on Mo(VI), W(VI), and V(V) with heteroatoms P and Si in acetone and acetic acid at 25°C. In acetone, H3PW12O40 and H4PW11VO40 are partially dissociated 3−1 electrolytes. In acetic acid, all the HPA investigated are 1-1 electrolytes. 2. Using the Fuoss-Edelson and Fuoss-Kraus methods they have calculated the thermodynamic dissociation constants and the limiting mobilities of HPA.

1. Silicotungstic heteropolyacid is sorbed by silica gels, activated charcoal, and γ-Al2O3 from water and from organic oxygen-containing solvents, forming three formations distinguishable by electron microscopy. 2. The relative proportions of the surface forms are determined by the type of substrate, solvent, and the HPA concentrations on the substrate. The most uniform covering is achieved when HPA is adsorbed from ethyl acetate.

1. The authors measure the electrical conductivities of heteropoly acids (HPA) of the compositions H3PMo12O40, H4PMo11VIMoVO40, H4PMo11VO40, H4SiMo12O40 and H4SiW12O40 in ethanol and acetone at 25°C. In the concentration range 10−5−10−3 mole/liter, all the HPA are partly dissociated 2−1 electrolytes; dissociation to the third and fourth degree is not manifested. 2. Using the Fuoss-Edelson method, they calculate the thermodynamic dissociation constants K2 and the limiting mobilities of the HPA.

The tungsten heteropoly acids in acetic acid are the most active in the dealkylation of 4-alkyl-2,6-di-tert-butylphenols. The reaction is first order with respect to the substrate and with respect to the HPA, and water slows the reaction. It has been postulated that the dealkylation reaction is mediated mainly by the undissociated molecules of the HPA.

1. The catalytic activity of heteropoly acids (HPA) in the reaction for the electrophilic addition of AcOH to 1-hexene is slightly dependent on the composition of the HPA and substantially exceeds the activity of H2SO4. The catalytic activity correlates with the dissociation constants of the acids. 2. The activity of the W HPA is higher than that of the Mo HPA due to the reduction of the Mo HPA during reaction, which leads to a decrease in their dissociation constants.

The authors have measured the Hammett acidity functions H0 of concentrated solutions of H3PW12O40 in water, aqueous dioxane, and acetic acid. In these solvents the acidity of H3PW12O40 is higher than those of sulfuric and hydrochloric acids.