摘要:

Infrared spectrophotometry has been used to compare the hydrogen–bonding (H-bonding) interactions in the set of solid trialkylammonium salts and double salts (R3NH)3[DMP], (R3NH)C1, and (R3NH)3[DMP].3(R3NH)C1, (A), where R represents a straight or methyl–branched alkyl group containing 8 to 13 carbons and DMP is the large dodecamolybdophosphate anion PMO12O403- Through an examination of the characteristic heteropolymolybdophosphate vibrational bands of A and (R3NH)3[DMP], the complex anion is identified as α–DMP and shown to be in an environment chemically similar to its tetrabutylammonium salt. A relatively weak H–bond in (R3NH)3[DMP] is indicated by small downward shifts in the N–H stretching frequencies νNH of the trialkylammonium cations from the hypothetical free–ion value. By contrast, large shifts in νNH induced by strong H–bonding occur in the salts (R3NH)C1. In the double salts A, the intermediate value of νNH suggests the existence of compTex cations like like [R3NH…cl…HNR3]+. The effect of amine structure on the infrared spectra is minor in all of the compounds studied except that methyl–branching increases the downward shift of the N–H stretching frequency of the salts (R3NH)C1; this is interpreted as evidence that methyl branching strengthens the H–bond by decreasing the basicity of the parent amine. Density and unit–cell data are also reported for some of the DMP–containing compounds. Possible relationships between the present results and previously observed solubility patterns are discussed.

ISSN:0736-6299    

DOI:10.1080/07366298808917922

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The rate of the extraction of zinc by trilaurylammonium chloride (TLAHC1) dissolved in toluene was investigated at different aqueous chloride concentrations, using lithium chloride as bulk electrolyte, ranging from 0.5 mol.dm -3 to 2.0 mol dm -3. The experiments were performed using a modified Lewis cell at 25 °C. The rate of metal extraction was found to increase by increasing the aqueous chloride concentration. The data treatment indicated that ZnCl2and ZnCl42-are both kinetically active species. The addition reaction with ZnCl2is favoured at low chloride concentration while the anion exchange of ZnCl42-prevails at high chloride concentration. The addition reaction was explained in terms or interfacial reaction steps. The anion exchange reaction, due to its fast nature, seems to be controlled by diffusion.

ISSN:0736-6299    

DOI:10.1080/07366298808917923

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Metal nitrates solvated by octyl(phenyl)–N,N–diisobutylcar-bamoylphosphine oxides exhibit a limited solubility in many alkane diluents even in the presence of a modifier such as tributyl phosphate. The solubility is a nonmonotonous function of the aqueous nitric acid concentration. The solubility of Nd(III) nitrate strongly increases with temperature, branching of the diluent molecule, and the concentration and the molecular weight of a trialkyl phosphate modifier. The solubility also increases when tributyl phosphate is replaced by dibutyl butylphosphonate. Increasing molecular size of n-alkane diluents and branching of the octyl group in the phosphine oxide molecule strongly suppress the solubility. With the n-octyl(phenyl) –N,N–diisobutylcarbamoyl-methylphosphine oxide extractant, the solubility of solvated Nd(III) nitrate is unlimited In the mixed isoparaffinic diluent Isopar–L, and the solvent can be loaded up to a metal to extractant ratio of 1/2. Empirical equations were derived which describe the solubility of Nd(III) nitrate, the distribution ratio of Nd(III), and the distribution ratio of nitric acid as functions of the nitric acid and Nd(III) concentrations in the equilibrium aqueous phase. Empirical equations were also derived which describe the density of the loaded organic phase as a function of the Nd(III) or U(VI) and aqueous nitric acid concentrations.

ISSN:0736-6299    

DOI:10.1080/07366298808917924

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The TRUEX (TRansUranium Extraction) process, recently developed at Argonne National Laboratory, separates and concentrates transuranium elements from acidic nuclear wastes. It is based on the use of the neutral extractant octyl(phenyl)–N,N–diisobutylcarbamoylmethylphosphine oxide (CMPO). CMPO Is combined with tributylphosphate (TBP) and a diluent to formulate the TRUEX process solvent. An attractive feature of the TRUEX process is that it allows the separation of americium from plutonium by using two different strip solutions. A detailed knowledge of the chemistry of americium in the stripping stages is essential for a successful Am/Pu separation. In this work the distribution ratio of Am(III) between TRUEX process solvent and diluted nitric acid has been measured in up to six successive strip experiments. The behavior of americlum during stripping has been correlated to the purity of the CMPO and the composition of the feed solution. With simulated waste solutions and with SX-grade CMPO, it is possible to remove more than 99.99% of americium from the loaded organic phase.

ISSN:0736-6299    

DOI:10.1080/07366298808917925

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The synergistic extraction of trivalent Am, Cm, Cf and Eu with mixtures of 1—phenyl—3—methyl 1—4— trifluoroacetyl pyrazolone—5 ( HPMTFP) and a crown ether dicyclohexano—18—crown—6 (DCH18C6) or monobenzo—15—crown—5 ( B15C5) has been studied in chloroform. With DCH18C6 the synergistic species extracted are M(PMTFP)3 (HPMTFP) (DCH18C6) where N = Am, Cm and Eu and Cf ( PMTFP)3. (DCH18C6) whereas with B15C5 the species are M( PMTFP) 3.n( B15C5), n being 1 or 2 for all these metal ions. The possibility of high coordination numbere for theee metal ions in the above syeteme and the probable reaeone for the anbormel order of synergistic constants namely K2≫81 have been discussed.

ISSN:0736-6299    

DOI:10.1080/07366298808917926

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Liquid-liquid equilibrium, solubility and tie-line data, for the quaternary system Water-Phosphoric Acid-l-Pentanol-3-Pentanone, were obtained at 25°C and atmospheric pressure, using an analytical method. 1-Pentanol appears to be more effective than 3-Pentanone as extractant solvent of phosphoric acid. Advantages are not observed with the use of mixed solvents in the purification of wet process phosphoric acid by means of solvent extraction.

ISSN:0736-6299    

DOI:10.1080/07366298808917927

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

A quantitative study of the effect of sodium chloride has been made on the quaternary liquid-liquid equilibria Water-Phosphoric Acid-i-Pentanol-3-Pentanone at 25°c and atmospheric pressure. Mutual solubility and tie-line data are obtained at saturation of sodium chloride in both conjugated phases. The addition of sodium chloride increases the distribution coefficient of phosphoric acid and the selectivity of extractant solvents for i-Pentanol and mixtures of 1-Pentanol and 3-Pentanone, whereas it has no significant influence when the extractant solvent is 3-Pentanone.

ISSN:0736-6299    

DOI:10.1080/07366298808917928

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

ISSN:0736-6299    

DOI:10.1080/07366298808917929

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The thermal desorption of molybdenum(VI)-oxide from an inorganic adsorber matrix is an efficient new procedure for the final purification of fission molybdenum from inorganic and organic impurities. The investigations presented in this paper served to find out suitable thermally resistant inorganic ion exchangers and practical loading conditions for the preceding chromatographic sorption of molybdate anions from the process solution, in batch distribution experiments the influence of HN03-molarity, Mo-concentration and molybdenum loading on the Mo-sorption of Al2O3, SnO2, MnO2and Sb2O5is described in terms of their retention capacities and distribution coefficients. It could be confirmed that the retention capacity - as expected -depends strongly on the specific surface area, crystallinity and acidity of the oxide. AL2O3and SnO2with capacities of 30 and 4.7 mg Mo/g ion exchanger, respectively, proved to be superior to MnO2and Sb2O5owing to their faster Mo-sorption and better stability against abrasion.

ISSN:0736-6299    

DOI:10.1080/07366298808917930

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Results of the studies on separation of hefnium /IV/ from zirconium /IV/ by frontal analysis on chelating ion-exchangers of different types have been presented. The phosphonic ion-exchanger Duolite ES-63 proved to be the best in zirconium sulphate purification from hafnium /IV/ among the examined chelating ion-exchangers.

ISSN:0736-6299    

DOI:10.1080/07366298808917931

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor