RING-SIZE AND SUBSTTTUENT EFFECTS IN THE SOLVENT EXTRACTION OF ALKALI METAL NITRATES BY CROWN ETHERS IN 1,2-DICHLOROETHANE AND 1 -OCTANOL

ABSTRACT

The extraction of alkali metal nitrate salts by solutions of crown ethers in each of the two diluents 1,2-dichlorethane and 1-octanol has been surveyed. The crown ethers include 18-crown-6, 21-crown-7, and 24-crown-8 ethers bearing cyclohexano, benzo, t-alkylbenzo, and/or furano substitutents. The extraction efficiencies of the different crown ethers are examined in terms of ring-size, substituent, and solvent effects. Partition ratios for the crown ethers between water and either 1,2-dichloroethane or 1-octanol are discussed. The extraction selectivities, expressed as the separation factor for cesium over sodium, are examined in relation to crown ether structure.     

EXTRACTION OF CESIUM NITRATE FROM CONCENTRATED SODIUM NITRATE SOLUTIONS WITH 21-CROWN-7 ETHERS: SELECnVITY AND EQUILIBRIUM MODELING

ABSTRACT

The extraction of cesium nitrate from a high concentration of sodium nitrate by a family of 21-crown-7 ethers in 1,2-dichloroethane has been investigated. Dibenzo-21-crown-7 (DB21C7) and bis[4(5),4′(5′)-rm-butylbenzo]-21-crown-7 (BtBB21C7) ethers have higher selectivity for cesium but lower extraction efficiency than dicyclohexano-21-crown-7 (DC21C7) ether. As measured by the distribution coefficient ratio D_cs/D_Na, the cesium selectivity averaged 78 and 93 for DB21C7 and BtBB21C7, respectively. However, in the case of DC21C7, the cesium selectivity was lower and decreased approximately three-fold from 10 to 3 as cesiüm loading increased. Alkyl substitution on the benzo group has only a small effect on the extraction behavior. It was shown by use of the equilibrium modeling program SXLSQI that the extraction of sodium and cesium could be adequately modeled by augmenting the previously determined cesium nitrate equilibrium model with a 1:1 Na⁺:crown organic-phase complex. No evidence for a mixed-metal species was found. In accord with our previous study, cesium nitrate extraction entails formation of a 1:1 Cs⁺:crown complex, but a minor 1:2 complex also forms in the case of DC21C7. Although the sodium and cesium made possible by the U. S. Department of Energy Postgraduate Research Program administered by the Oak Ridge Associated Universities.     

SOLUBILITY IN ORGANIC DILUENTS AND EXTRACTION BEHAVIOR OF CALIX[4]ARENE CARBOXYLATES WITH DIFFERENT ALKYL CHAINS

ABSTRACT

Two types of alkylcalix[4]arene carboxylates with different alkyl chains, together with three types with the same alkyl chains were synthesized to investigate their solubility in four different organic diluents. The solubility was found to be enhanced by using the calixarene compounds with longer alkyl chains and by using mixtures of compounds with different alkyl chains. The order of solubility in the different organic diluents was found to be:

chloroform > toluene ? EXXSOL D80 ≈ hexane.

The stoichiometry of the copper complex with the compounds having the same alkyl chains was also determined and the maximum loading capacity of copper with each extractant was estimated.     

SOLVENT EXTRACTION OF THE RARE-EARTH METAL IONS BY A CONE-SHAPED CALDC[4]ARENE SUBSTITUTED AT THE LOWER RTM BY FOUR -CH2P(O)Ph2 LIGANDS

ABSTRACT

The extraction properties of cone-5,11,17,23-tetra-t-butyl-25,26,27,28-tetrakis(diphenylphosphinoylmethoxy)calix[4]arene (1) in 1,2-dichloroethane towards rare-earth metal ions at 25 °C have been investigated. The slope analysis showed a 1:1 metal/ligand ratio for the extracted species (La, Eu, Er and Y). The distribution coefficients increase with the polarity of the diluents : chloroform ≤ dichioromethane ≤ 1,2-dichloroethane ≤ nitrobenzene. In the competitive extraction of 11 rare-earth metal ions (La, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb and Y), ligand 1 exhibits higher extraction efficiency and a better separation factor than tri-n-octylphosphine oxide.     

THIRD PHASE FORMATION IN EXTRACTION OF THORIUM NITRATE BY MIXTURES OF TRIALKYL PHOSPHATES

ABSTRACT

This paper reports the results of the studies on third phase formation during the extraction of thorium nitrate from zero free acidity solutions by mixtures of trialkyl phosphates. The phosphates used are tri n-butyl phosphate(TBP), triiso butyl phosphate(TiBP), tri sec butyl phosphate (TsBP) and tri n-amyl phosphate(TAP). The results indicate that small additions of a homologous phosphate can alter the Limiting Organic Concentration (LOC) above which the third phase formation takes place and thus can be advantageously utilised. Use of mixtures of the trialkyl phosphates as extractant can thus obviate the need for adding modifiers such as alcohols to the organic phase for avoiding third phase formation.     

溶剂萃取法制备农用硝酸钾

通过实验研究确立了溶剂萃取法制备硝酸钾的新的工艺流程,并优化了操作条件。在所确定的主要条件下,用溶剂Ⅰ、Ⅱ进行低温萃取,可得到氯含量较低的农用硝酸钾产品,经精制可得工业用产品。     

ANION EFFECT ON SELECTIVITY IN SOLVENT EXTRACTION OF ALKALI METAL SALTS BY CROWN ETHERS

ABSTRACT

The influence of the co-extracted anion upon competitive solvent extraction of five alkali metal cations from aqueous solutions into organic diluents by the cis-syn-cis and cis-anti-cis isomers of dicyclohexano-18-crown-6 has been assessed. The anions are bromide, chloride, iodide, nitrate, perchlorate, and thiocyanate and the organic diluents are chloroform and 1-octanol. The extraction efficiency is markedly influenced by the identity of the anion and exhibits some correlation with the inverse of the hydration enthalpy of the anion. Although potassium is the best extracted cation with all anions, the selectivities for potassium over lithium, sodium, rubidium, and cesium are strongly affected by anion variation in chloroform, but not in 1-octanol. The selectivity ordering in chloroform does not correlate with the hydration enthalpy or softness parameter for the anion. Instead it appears to result from variation of the dimensional structure and the availability of specific binding sites in the anion.     

CORRELATION OF THE EXTRACTION OF STRONTIUM NITRATE BY A CROWN ETHER WITH THE WATER CONTENT OF THE ORGANIC PHASE*

A simple correlation has been observed between the extraction of strontium nitrate from nitric acid solution by cis-dicyclohexano-18-Crown-6 dissolved in a variety of oxygenated, aliphatic diluents and the molarity of water present in the organic phase. This correlation is attributed to the extraction of the hydrated nitrate ion and its solvation by the diluent, facilitated by the high concentration of dissolved water. Of the solvents studied, ketones yield the largest values of the extraction constant for a given water content, although C₅ and C₆ alcohols give the highest overall values.     

STUDIES OF THORIUM NITRATE COMPLEXATION IN AQUEOUS SOLUTIONS BY A LIQUID-LIQUID EXTRACTION METHOD - APPLICATION TO THE CALCULATION OF THORIUM DISTRIBUTION IN THE THOREX PROCESSES

ABSTRACT

Apparent stability constants of the nitrato thorium complexes, Th(NO₃₊)³⁺Th(NO₃)₄, in aqueous solutions having ionic strengths in the range 0.5 to 3.0 mol/L have been determined using a liquid-liquid extraction method. The data have been used to calculate free nitrate ion concentrations in aqueous solutions with compositions typical of those in the THOREX extraction process. A model based on extraction chemistry has been developed to predict thorium distribution coefficients under a variety of conditions.     

EXTRACTION OF Ce(III) AND Eu(III) BY NITROBENZENE SOLUTIONS OF BIS-1,2-DICARBOLLYLCOBALTATE IN THE PRESENCE OF 18-CROWN-6

ABSTRACT

The extraction of Ce(III) and Eu(III) by nitrobenzene solutions of bis-l,2-dicarbollylcobaltate anions in the presence of 18-crown-6 from aqueous solutions of nitric acid has been investigated. Distribution ratios, the protonization and exchange extraction constants for the investigated systems has been determined. The calculated values of distribution ratios D have been compared with experimental ones.     

RECENT ADVANCES IN THE SOLVENT EXTRACTION OF MERCURY(II) WITH CALIXARENES AND CROWN ETHERS

This work is focused on the recent advances, mainly achieved during the past ten years on the solvent extraction separation of mercury from aqueous solutions using macrocyclic ligands such as calix[n]arene derivatives and crown ethers.     

[Fe（CN）6]^4—在溴碘化银T—颗粒乳剂中的掺杂

本文研究了K4[Fe(CN)6]掺杂对溴碘化银T-颗粒乳剂感光性能的影响.结果表明,掺杂剂的掺杂量以及掺杂位置对乳剂的感光性能都有影响.K4[Fe(CN)6]的掺杂量在每克乳剂3.1×10-93.1×10-11mol之间时,乳剂感光度都有提高.最佳掺杂量为每克乳剂3.1×10-10mol.掺杂位置接近表面时效果相对较好,表明K4[Fe(CN)6]是浅电子陷阱掺杂剂.当掺杂剂的掺杂量大于每克乳剂3.1×10-8mol,且掺杂位置在乳剂颗粒较深内部时,乳剂的感光度反而下降.     

电极生物膜处理地下水中的硝酸盐氮实验研究

采用电极生物膜法研究处理含硝酸盐氮的地下水.结果表明,温度过低威过高,对反硝化细菌的活性都有一定抑制;m(C)/m(N)为1时能实现总氮与总碳的同时去除,与理论计算的最经济m(C)/m(N)为1.07相近;电流的刺激作用可以提高异养反硝化菌的脱氮效率,其脱氮率和电流之间有大的关系,同时硝酸盐氮的负荷越大,电流要求越高;HRT越长,硝酸盐的去除率越高.     

SOLVENT EXTRACTION OF URANIUM(VI) AND THORIUM(IV) WITH A TETRA-CARBOXYLATED CALIX[4]ARENE AND EFFECT OF ALKALI IONS (Na+, K+)

ABSTRACT

The solvent extraction of uranium(VI) and thorium(IV) with a tetra-carboxylated calix[4]arene (LH₄) in chloroform has been studied in the presence or absence of alkali ions (M⁺=Na⁺, K⁺). When studied alone, UO₂ ²⁺ and Th⁴⁺ were extracted into chloroform as 2:2 and 1:1 metal:ligand complexes, respectively. The efficiency of extraction increases in the presence of alkali ions, due to the formation of heteronuclear complexes. For uranium(VI), the extracted species are found to be both 2:2:2 and 1:1:1 (uoi₂ ²⁺:M⁺:LH₄,) mixed complexes. For Th(IV) in the presence of Na⁺, the formation of a mixed complex in 1:1:1 (Th(IV):Na⁺:LH₄,) proportions has been evidenced. However, the exact nature of this species could not be determined. In practical grounds, LH. may be useful as a selective extracting agent for Th(IV) with respect to U(VI) since separation factor Th(IV)/U(VI) close to 1000 have been measured in competitive extraction, in the presence or absence of alkali ions.     

氯酸锂电解液中高氯酸锂的分光光度测定

在氯酸锂电解液中,用硫酸亚铁使氯酸盐还原,当ｐＨ＝３～４时,用苯萃取ＬｉＣｌＯ４灿烂绿络合物,测定了高氯酸锂。在２５ｍＬ萃取液中,ＬｉＣｌＯ４于２～１００μｇ范围内遵守比尔定律。大量Ｎａ＋,Ｋ＋,Ｍｇ２＋,Ｐｂ２＋,Ｍｎ２＋,Ｆｅ３＋,Ｆ－,Ｃｌ－,ＳＯ２－４,ＣＨ３ＣＯＯ－和少量的ＣｒＯ２－４不影响测定。该法也可用于氯酸盐产品中微量高氯酸根的测定