Interaction of basalt with hydrochloric acid

Physicochemical modeling and experimental investigations are performed to study the interaction of basalt with hydrochloric acid. The equilibrium compositions of the liquid and solid phases of the basalt-hydrogen chloride-water system are calculated. The effects of the hydrochloric acid concentration and solid-to-liquid weight ratio on the phase composition of reaction products are quantified, and the degrees of extraction of iron, aluminum, calcium, sodium, and silicon into liquid are determined. The results of physicochemical modeling are compared with the experimental data. Conditions for selective extraction of the basalt components into solution are estimated.     

Interaction between spin-labelled penicillins and lanthanide ions

The penicillin (1b) [spin-labelled with a nitroxide group] has been prepared by reacting 6-amino-penicillanic acid (1e) with 3,5-dibromo-4-oxo-2,2,6,6-tetramethylpiperidin-1-oxyl (2). Penicillin (1b) is a potential probe for proteins (e.g. penicillinases) which bind penicillins. Because it is intended to use paramagnetic metal ions as additional probes in studies of proteins with (1b), an investigation has been carried out of the interactions of (1b) and the related ester (1d) with a series of lanthanide ions. It is shown that a direct interaction between the nitroxide group of (1b) [or (1d)] and the metal ion leads to contact quenching of the EPR spectrum of (1d).     

Reaction of lanthanide(II) and lanthanide(III) phenylethynyl cuprates with acetyl chloride

Praseodymium and ytterbium phenylethynyl cuprates [(PhC≡C)₃Cu]₃Pr₂(THF)₆ and {[(PhC≡C)₃Cu]·Yb(THF)₂}₂ react with acetyl chloride in tetrahydrofuran with elimination of phenylethynylcopper and formation of alkoxides [PhC≡C-CCl(CH₃)O] _n Ln (n = 3, Ln = Pr; n = 2, Ln = Yb). Then praseodymium alkoxide forms ester [methyl (phenylethynyl)chloromethylethanoate] and praseodymium chloride, alkoxy derivative. Itterbium alkoxide is oxidized to unsymmetrical dialkoxyitterbium chloride PhC≡C-CH(CH₃)-O-Yb(Cl)-O-CCl(CH₃)C≡CPh·2THF.     

Interaction between f-electronic systems in dinuclear lanthanide complexes with phthalocyanines

The first detection and characterization of the interactions between the f-electronic systems in the dinuclear complexes of paramagnetic trivalent Tb, Dy, Ho, Er, Tm, and Yb ions with phthalocyanine ligands are presented. The molar magnetic susceptibilities, chi(m), were measured for PcLnPcLnPc* ([Ln, Ln]; Pc = dianion of phthalocyanine, Pc* = dianion of 2,3,9,10,16,17,23,24-octabutoxyphthalocyanine) and PcLnPcYPc* ([Ln, Y]) in the range from 1.8 K to room temperature. The selective synthetic method previously reported for the heterodinuclear complex [Y, Ln] was used to prepare [Ln, Ln] and [Ln, Y] with a modification on the choice of starting materials. The f-f interaction contributions to the magnetic susceptibility are evaluated as Delta(chi)(m)T = chi(m)([Ln, Ln])T - chi(m)([Ln, Y])T - chi(m)([Y, Ln])T, where T refers to temperature on the kelvin scale. The homodinuclear complexes having f(8)-f(10)-systems, namely [Tb, Tb], [Dy, Dy], and [Ho, Ho], show positive Delta(chi)(m)T values in the 1.8-50 K range, indicating the existence of ferromagnetic interaction between the f-systems. The magnitude of the Delta(chi)(m)T increases in the descending order of the number of f-electrons. [Er, Er] gives negative Delta(chi)(m)T values in the 1.8-50 K range, showing the antiferromagnetic nature of the f-f interaction. [Tm, Tm] exhibits small and negative Delta(chi)(m)T values, which gradually decline in the negative direction as the temperature decreases in the range 13-50 K and sharply rise in the positive direction as the temperature falls from 10 to 1.8 K. [Yb, Yb] has extremely small Delta(chi)(m)T values, whose magnitude at 2 K is less than 1% of that of [Tb, Tb]. The ligand field parameters of the ground-state multiplets of the six [Ln, Y] complexes are determined by simultaneous fitting to both the magnetic susceptibility data and paramagnetic shifts of (1)H NMR. The theoretical analysis successfully converged by assuming that each ligand field parameter is a function of the number of f-electrons in each ion. Using these parameters as well as the previously obtained corresponding parameters for the [Y, Ln] series, the interactions between the f-systems in [Ln, Ln] are investigated. All the characteristic observations above are satisfactorily reproduced with the assumption that the magnetic dipolar term is the sole source of the f-f interaction.     

Kinetics of proton exchange between semiquinone radicals and hydrochloric acid

The mechanism of proton exchange between semiquinone neutral radicals 3,6-di-tert-butyl-2-hydroxyphenoxyl (1), 6-tert-butyl-3-chloro-2-hydroxy-4-triphenylmethylphenoxyl, and hydrochloric acid in toluene solutions has been studied. The rate of proton exchange with hydrochloric acid is less than that with acetic acid owing to the higher thermodynamic stability of the radical cation formed upon semiquinone radical protonation by hydrochloric acid. The formation of radical cations and their dimers has been proven by spectroscopy.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No 1, pp. 84–87, January, 1993.     

Reaction of fluoronitroacetic acid with hydrochloric acid

Conclusions Fluoronitroacetic acid reacts with hydrochloric acid to form fluorochloronitrosome-thane which is capable of undergoing dimerization to give N,N'-azofluorochlormethane dioxide.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1420–1422, June, 1985.     

Ice-catalyzed ionization of hydrochloric acid

Ionization of hydrochloric acid (HCl) on stratospheric ice particles is believed to be a key step in the depletion of stratospheric ozone. Ab initio calculations based on a model HCl-water cluster show that HCl ionization on ice surfaces is a barrierless process. Since this mechanism is rapid and produces chloride anions that are exposed to ambient stratospheric chlorine reservoir molecules, it is likely to be important for stratospheric chemistry. It complements a previously suggested mechanism where HCl forms part of the ice lattice before ionizing. The mechanism proposed here is also consistent with experimentally observed ionization of HCl on ice at low temperatures and under vacuum, where the HCl is not expected to be encapsulated in the ice lattice.     

Flash photolysis study of complexes between salicylic acid and lanthanide ions in water

In the natural environment humic substances (HS) represent a major factor determining the speciation of metal ions, e.g., in the context of radionuclide migration. Here, due to their intrinsic sensitivity and selectivity, spectroscopic methods are often applied, requiring a fundamental understanding of the photophysical processes present in such HS-metal complexes. Complexes with different metal ions were studied using 2-hydroxybenzoic acid (2HB) as a model compound representing an important part of the chelating substructures in HS. In flash photolysis experiments under direct excitation of 2HB in the absence and the presence of different lanthanide ions, the generation and the decay of the 2HB triplet state, of the phenoxy radical, and of the solvated electron were monitored. Depending on the lanthanide ion different intracomplex processes were observed for these transient species including energy migration to and photoreduction of the lanthanide ion. The complexity of the intracomplex photophysical processes even for small molecules such as 2HB underlines the necessity to step-by-step approach the photochemical reactivity of HS by using suitable model compounds.     

Interactions between oxygen reduction and titanium dissolution in aerated hydrochloric acid: Topographic implications

The presence of dissolved oxygen inhibits the anodic dissolution of titanium, predominantly in the active range. The reduction rate of oxygen partially limited by its diffusion is shown to depend on the potential and to be localized on active islets each one of which has its own diffusion layer. A mixed kinetics for this reduction reaction is observed in the active range and a pure diffusional one in the near passivity range. The corrosion morphologies are correlated with the various kinetics and localizations observed for the oxygen reduction.     

Matrix isolation infrared spectra of the complexes between methylacetate and water or hydrochloric acid

The hydrogen-bonded complexes between methylacetate (MeAc) and water or hydrochloric acid have been studied by infrared spectrometry in a low temperature Argon matrix. The ν_CO, ν_CC and ν_CC ional modes of MeAc show a splitting to the low and to the high frequency side of the free molecule. This suggests that water and HCl interact with the keto and ether oxygens. This conclusions is supported by the appearance of two main absorptions in the ν_HCl region. These results are discussed as a function of the gas-phase basicity of the two oxygen atoms, derived from the O(1s) core electron binding energies and from the ionization potentials.     

盐酸法湿法磷酸中磷酸的协同萃取分离

选择对磷酸萃取率高 ,而对杂质的排斥性好的萃取剂 ,一直是业内人士长期关注的一个课题[1～ 3] 。本文以盐酸分解磷矿制得的粗磷酸为原料 ,对萃取磷酸的不同萃取剂如ＴＢＰ、ＴＲＰＯ、异戊醇、环己酮、环己醇等进行了筛选 ,最后选用体积比为 6∶4的三级逆流萃取和相比为 1∶2 .5的单级萃取 ,测定了各组分的分配系数和分离系数 ,并与使用其它萃取剂的结果作了比较。本文同时还测定了用 6 %ＨＣｌ水溶液和纯水对萃得有机相进行反洗的情况。1　实验部分1 1　试剂磷矿粉 ,40～ 1 0 0目 ,取自连云港锦屏磷矿 ;ＴＲＰＯ(三烷基氧化膦 ,加拿大Ｃ…     

Protonation and solvent extraction of N-p-tolylbenzohydroxamic acid in hydrochloric acid medium

the protonation of N-p-tolylbenzohydroxamic acid (p-TBHA) in aqueous hydrochloric acid has been investigated by determination of its distribution between cyclohexane and hydrochloric acid. The pK(a) value found was - 2.30 +/- 0.02 at 30 degrees . The solubility of p-TBHA as a function of hydrochloric acid concentration has also been determined. At lower acid concentrations the solubility decreases owing to a salting-out effect, whereas at higher concentrations it increases because of formation of the more hydrophilic protonated species and a salting-in effect. Intramolecular hydrogen-bonding observed in p-TBHA provides evidence for protonation of the nitrogen atom.     

Reaction between U(IV) and H2O2 in hydrochloric acid medium

Kinetic investigations on the reaction between U(IV) and H₂O₂ have been carried out at different acidities in chloride medium at an ionic strength of 2M. The observed bimolecular rate constant has been found to be dependant on [H⁺]^?1.3. The activation energy of the overall reaction has been found to vary from 13.4 ± 0.7 to 18.0 ± 0.8 kcal/mol in the range of acidity from 0.3 to 1.5M. The results have been explained on the basis of three parallel rate-controlling reactions involving unhydrolyzed species of U(IV) and hydrolyzed species UCl(OH)²⁺ and UO²⁺. The values of the rate constants for these three reaction paths have been found to be of the order of 3.95, 5.59 × 10³, and 1.49 × 10⁵M^?1 min^?1, respectively.