Double phosphate crystallization in phosphate liquids

The discussion concerns the interactions of oxides of metals in groups III–VIII not with individual molten phosphates but with mixtures of them, which provides a range in M₂O:P₂O₅ in the phosphate liquid from 0.5 to 2.0; this constitutes a new approach to these reactions, and it enables one to determine unambiguously the ranges in which double phosphates are formed and to define the conditions under which the individual crystals are produced from those liquids.Kiev University. Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 27, No. 3, pp. 307–311, May–June, 1991. Original article submitted February 19, 1991.     

Titrimetric determination of phosphates and monofluorophosphates in tooth pastes

Summary Titrimetric methods for a fast determination of phosphates and monofluorophosphates in tooth pastes are described. They are based on the precipitation of PO ₄ ^3– -ions (directly or after the hydrolysis of PO₃F^2–-ions) as BiPO₄ in nitric acid (pH 0.1–0.5). The end-points are detected visually (back EDTA-titration of the non-bonded Bi³⁺-ions), or potentiometrically (direct titration of phosphates with bismuth by a specially prepared Bi/Bi₂O₃-electrode). The titrations are performed without separating the precipitate. An ultrasonic field is applied to accelerate the destruction of the dentifrices.     

Mixed-mode liquid chromatography of aliphatic anionic surfactants with a naphthalenetrisulfonate mobile phase

Summary Separation of three classes of anionic surfactants (alkyl sulfates, alkanesulfonates, and alkyl phosphates) are achieved on a mixed-mode reversed phase (RP) phenyl/-anion exchange column using a naphthalenetrisulfonate (NTS)-acetonitrile (ACN) mobile phase via indirect photometric, indirect fluorometric, direct or indirect conductivity detection. Mixtures of C₅–C₁₈ sulfates, C₆–C₁₈ sulfonates, and C₁–C₄ phosphates (mono- and di-ester) can be separated in less than 20, 24, and 20 min respectively. Although hydrophobic effects are more pronounced in mixed-mode chromatography, equivalent-per-equivalent exchange of analysis and eluent ion is still required for sensitive indirect photometric, fluorometric, or conductivity detection. The detection limits of alkyl sulfates and alkanesulfonates are in the range of 3–15 pmoles which are at least an order of magnitude better than suppressed conductivity detection. The determination of surfactants in a variety of real samples is also presented.     

Synthesis of trialkyl (dialkoxyphosphorylimido)phosphates

Conclusions (Dichlorophosphorylimido)phosphorus trichloride reacts with sodium alcoholates in the corresponding alcohol as the medium to give trialkyl (dialkoxyphosphorylimido)phosphates in 40–90% yield.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1884–1886, August, 1979.     

Conversion of solid amorphous mixed zirconium-titanium phosphates into crystalline from by molten oxalic acid

Solid amorphous mixed zirconium-titanium phosphates, with general formula Zr_xTi_/1–x//HPO₄/₂.n H₂O/ where x=0.1–1, and n=3–5/, are mixed with an excess of solid oxalic acid dihydrate and digested in molten oxalic acid. Then oxalic acid is removed by extraction and the residue washed with dilute /O.OlM/ HCl solution and bidistilled water. As a result of this method, crystalline mixed zirconium-titanium phosphate is formed.     

Mixed insoluble acidic salts of tetravalent metals

Solid amorphous Zr-, Ti- and Zr_xTi_(1–x) phosphates (where x=0.10, 0.33, 0.66, and 0.90) in various sodium forms were contacted with an excess of solid oxalic acid dihydrate to its molten state for a given time. The oxalic acid was removed by extraction and the residue was washed with redistilled water. As a result of this, crystalline forms of Zr-, Ti-, and Zr_xTi_(1–x) phosphates were obtained. Using various sodium forms of the initial samples, higher rate of crystallisation resulted than that found in case of hydrogen forms of initial samples.     

Asymmetric oxidation of enol phosphates to α-hydroxy ketones by (salen)manganese(III) complex. Effects of the substitution pattern of enol phosphates on the stereochemistry of oxygen transfer

This paper presents a study of enantioselective catalytic oxidation of a variety of differently substituted, cyclic (E) and acyclic (Z)-enol phosphates. The asymmetric oxidation of acyclic (Z)-enol phosphates containing alkoxy substituents in the phosphate group 2a, c, e–g, i, and j and Z-configured enol phosphates containing aryloxy substituents in the phosphate group 2b, d, and h afforded optically active α-hydroxy ketones 4a–j of opposite configuration with good to high enantioselectivity. The influence of electronic and steric effects of the enol phosphate substituents on the stereoselectivity of oxidation was studied.     

Lithium complexes and the kinetics of interactions of zinc ions with tetra(N-methyl-4–pyridyl)porphyrins in basic solution

The acidity of the free base (H2–P(X)) forms of the tetra- (N-methyl-4–(3 or 2)pyridyl)porphyrins were studied in basic solutions at 25 C, I=0.50. Equilibrium constants for both the H2– P(X)=P(X)2–+2H+ and the Li++ P(X)2–=Li- P(X)– reactions are reported. Log (KS) values for the Mn++P(4)2–=M- P(4)(n–2) reactions are 2.6 for Li+, 17.6 for Cd2+, 17.8 for Pb2+, 19.6 for (OH)2Hg, 25.9 for Zn2+ and 19.6 for the formation of Hg2–P(4)2+. Zn(OH)3– shows similar kinetic reactivity with both H2–P(4) and P(4)2– to form Zn- P(4) and HO-Zn- P(4)–,whileZn(OH)42– is unreactive with either species. For Zn2+, Zn(OH)+ and Zn(OH)3– with H2–P(4) the relative kinetic order for this tetrapositive macrocycle was ca. 1:300:20,000, while the trend Zn(OH)+>Zn2+>Zn(OH)3– is the usual pattern for peripherally negatively charged porphyrins.     

Reaction of dialkyl phosphites with 1,1-dichloronitrosoalkanes

Conclusions Dialkyl phosphites react with 1,1-dichloronitrosoalkanes at 20C over 5–6 days to give the corresponding alkylchloroformimlnodialkyl phosphates.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 226–228, January, 1987.     

Model analysis of zeolite-like phosphates and their adsorption complexes with water molecules

Molecular models of borophosphates, aluminophosphates, and silicon-containing derivatives of these phosphates have been subjected to quantum-chemical analysis in the MNDO approximation. Bonding energies of these compounds with water molecules have been calculated. Incorporation of silicon atoms into the phosphate matrix increases its hydrophilicity and acidity.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 30, No. 4, pp. 223–226, July–August, 1994.     

Synthesis and isomerization of O,O-dialkyl-O-thioglycidyl thiophosphates

Conclusions O,O-Dialkyl-O-thioglycidylthione phosphates obtained by the reaction of O,O-dialkylglycidyl thiophosphates with the ammonium or triethylanmonium salts of dialkylthiophosphoric acids undergo isomerization to give O,O-dialkyl-S-thioglycidylthiol phosphates by the action of both the initial salts and the salts formed.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2363–2366, October, 1982.     

Reaction of superacid HGeCl3 with aromatic compounds. 8. Formation of long-lived carbocations stabilized by the GeCl3 anion in the reaction with 1,3-dialkoxybenzenes; crystal structure of 1,1,3,5-tetrakis(trichlorogermyl)-3-ethoxycyclohexane

Cyclohexenyl cations that are long-lived at –50°C are stabilized by the GeCl₃ ^– anion and are detected and characterized spectrally in reactions of HGeCl₃ with 1,3-dialkoxybenzenes. Further reactions of the cyclohexenyl cations are studied. The x-ray crystal and molecular structure of the final reaction product of HGeCl₃ with 1,3-diethoxybenzene — 1,1,3,5-tetrakis(trichlorogermyl)-3-ethoxycyclohexane — is solved.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 895–900, April, 1990.For previous communication, see [1].     

Study of kinetics and mechanism of sulfonation of thiophene and its derivatives by complex compounds of sulfuric anhydride

By quantitatively studying the sulfonation of thiophene and its homologs by complexes of sulfuric anhydride with ethers, amides, and trialkyl phosphates it was possible to determine kinetic and thermodynamic parameters of the process, to propose a S_E2 type reaction mechanism and also to reveal a quantitative dependence of the rate constant of the sulfonation reaction of thiophene on the basicity of the complex-forming agent: The sulfonating activity of the complexes studied increases in the series — amides < trialkyl phosphates < ethers, which is the reverse of the increase in the basicity series of a donor.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 34–39, January, 1986.     

Chemical effects of nuclear transformations in mixed potassium hexahalogenometallates(IV), K2MXnY6−n

Damage initiated by halogen recoil atoms in mixed hexabromochlorometallates has been evaluated with the help of the impact-induced multiple Ligand Abstraction (IMULA) model. The essential reactions within the scope of the model are (1) primary retention for recoil atoms with energies below some threshold of displacement energy, (2) halide-halide substitution reactions (billiard ball reactions), (3) reactions in which two or more halide ligands are displaced with subsequent reoccupation of the vacancies by adjacent halides and (4) formation of interstitials which form free halide during the dissolution of the irradiated substances. It was found that for all recoil atoms and both potassium hexabromochlorometallates the contributions of the different reaction channels are very similar: (1) 4–18% (2) 40–50%, (3) 25–30% and (4) 12–20% These results do not differ essentially from results so far obtained in mixed crystal systems.     

Effect of sodium dodecyl sulfate on the reactivity of copper(II) complexes with 2-dimethylaminomethylphenol

The effects of the anionic surfactant sodium dodecyl sulfate on complex formation of 2-dimethylaminomethylphenol (1) with copper(u) in aqueous solutions and on the kinetics of the reactions of copper(n) complexes of 1 with 4-nitrophenylbis(chloromethyl)phosphinate (2) were studied. The reactivities of the complexes in these reactions are higher than that of 1 at all concentrations of SDS studied (0.010–0.200 mol L^–1 with pH 7–9.Translated from Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 361–365, February, 1996.     

Catalytic phosphorylation of pentafluorophenol with phosphoric acid chlorides

Conclusions A new method was developed for the preparation of pentafluorophenyl phosphates, which consists in the catalytic phosphorylation of pentafluorophenol with POCl₃, or with aryl and polyfluoroalkyl phosphates, in the presence of the salts of the metals of Groups I and II of the periodic system.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 896–900, April, 1979.     

Pulse radiolysis of Triton X-100 aqueous solution

Pulse radiolysis of deaerated aqueous solutions of 4·10^–5–2.4·10^–3 mol dm^–3 Triton X-100 gives rise to a transient species originating from the reactions of OH radicals and H atoms. The rate constants of these reactions were found to be 8.8·10⁹ mol^–1·dm³·s^–1 and 1.25·10⁹ mol^–1·dm³·s^–1, respectively, for Triton X-100 concentrations below CMC. The corresponding transient species were found to decay according to second order kinetics. The mechanism of the reactions involved including concentration effects is discussed.     

Pulsed Corona Discharge-Induced Reactions of Acetophenone in Water

The reactions of acetophenone in water by pulsed corona discharges have been investigated to provide fundamental information concerning the reactions of acetophenone in water. Experimental results indicated that photolysis of acetophenone did not involve a hydroxyl radical mechanism and the majority flux of hydroxyl radicals originated from the dissociation of gas-phase oxygen in the plasma channels. The rate constants for photolysis and pyrolysis were determined to be 1.5×10^–7 M-s^–1, 2.2×10^–4 s^–1, respectively. The rate constant for the oxidative reactions was measured as 1.2×10^–7 M-s^–1. Results from this study support the proposal that acetophenone degradation reaction proceed through the oxidative reaction pathway, where molecular oxygen accelerates acetophenone degradation, photolysis, and pyrolysis pathways.     

Analysis of the electron density redistribution in the course of nucleophilic addition reactions of H− and F− to acetylene and methylacetylene molecules according toab initio calculations

Energy characteristics and peculiarities of variation of structural parameters along the minimum energy pathways (MEP) calculated earlier of six reactions of nucleophilic addition of H^– and F^– to acetylene and methylacetylene have been analyzed. The electronic mechanism of the reactions, the character of the electron density redistribution, and its relation with the changes in structural parameters have been discussed. It has been found for all six reactions that the structural reorganization of an alkyne + Nu system is completed before the barriers. However, the increase in the alkyne multiple bond length and changes in electronic characteristics for the reactions with F^– (endothermic reactions) take place before the barrier (late transition state) and for the reaction with H^– (exothermic reactions), after the barrier (early transition state).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2373–2377, December, 1995.     

Synthesis of ethyl bis(N-butyl-N-isobutenylamido)phosphite and reaction with α-chloroacetaldehydes

Conclusions Some vinyl bis(N-butyl-N-isobutenylamido)phosphates were synthesized, which exhibited herbicidal activity.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 700–702, March, 1982.