Solvent extraction agents

Uses Cross-linking agent organic synthesis solvent extracting agent. 

Use Refrigerant, solvent, extraction agent, propellant for sprays, chemical reaction medium, catalyst and stabilizer in polymerization. 

Undoubtedly a major cause of interest in ligands containing the phosphoryl group has been their usefulness as solvent extraction agents, and this has been reviewed by Peppard. For separation-of the actinides, OP(OBu")3 has been widely used. Extraction by OP(OBu )3 from aqueous phases occurs for a range of metals including Co" and the lanthanides. Conditions have a crucial effect on extraction efficiency, and counter ions such as NOf, Cl" and SCN" are often constituent ligands of the complex extracted. 

Castell OK, AUender CJ, Barrow DA (2006) Novel biphasic separations utilising highly selective molecularly imprinted polymers as biorecognition solvent extraction agents. Biosens Bioelectron 22(4) 526-533... 

Diethyl ether is widely used in the chemical industry as a solvent, extracting agent, and reaction medium on account of its chemical resistance in acid and alkaline... 

Detailed considerations of equilibria in such systems for the extraction of radioactive metals are available in Benedict et al. (1981). Normally water molecules form a shell around the metal atom, creating the hydration sphere. TBP has a highly polar group =P = O, which can replace water around the metal. Other extractants, like ethers, alcohols and ketones, have also been used to the same end, except water molecules are not completely excluded. Table 5.2.4 illustrates the variety of solvent extraction agents used commercially for extracting metals in hydrometallurgy. 

Figure 4 Schematic phase diagram of a binary system, consisting of a polymer and a solvent of marginal thermodynamic quality. The miscibility gap is shaded. Indicated in the graph is how the compositions of the working point (WP) can be reached either by cooling a homogeneous feed solution (FD, route A) or by adding pure solvent (extracting agent, EA) to a concentrated feed solution (FD, route B). The system demixes into a polymer-rich gel phase (GL) and a polymer-lean sol phase (SL).

Figure 4) or in composition (route B, Figure 4) by adding pure solvent (extracting agent, EA, Figure 5) to the feed solution. In both cases, one reaches the final conditions inside the miscibility... 

An improved solvent extraction process, PUREX, utilizes an organic mixture of tributyl phosphate solvent dissolved in a hydrocarbon diluent, typically dodecane. This was used at Savannah River, Georgia, ca 1955 and Hanford, Washington, ca 1956. Waste volumes were reduced by using recoverable nitric acid as the salting agent. A hybrid REDOX/PUREX process was developed in Idaho Falls, Idaho, ca 1956 to reprocess high bum-up, fuUy enriched (97% u) uranium fuel from naval reactors. Other separations processes have been developed. The desirable features are compared in Table 1. 

Chromium Removal System. Chlorate manufacturers must remove chromium from the chlorate solution as a result of environmental regulations. During crystallization of sodium chlorate, essentially all of the sodium dichromate is recycled back to the electrolyzer. Alternatively, hexavalent chromium, Cr, can be reduced and coprecipitated in an agitated reactor using a choice of reducing agents, eg, sodium sulfide, sulfite, thiosulfate, hydrosulfite, hydrazine, etc. The product is chromium(III) oxide [1333-82-0] (98—106). Ion exchange and solvent extraction techniques have also... 

Butyl Ether. -Butyl ether is prepared by dehydration of -butyl alcohol by sulfuric acid or by catalytic dehydration over ferric chloride, copper sulfate, siUca, or alumina at high temperatures. It is an important solvent for Grignard reagents and other reactions that require an anhydrous, inert medium. -Butyl ether is also an excellent extracting agent for use with aqueous systems owing to its very low water-solubiUty. 

Three external MSAs are considered a solvent extractant (S2), an adsorbent S3), and a stripping agent (S4). The data for the candidate MSAs are given in Table 3.9. The equilibrium data for the transfer of the pollutant from the waste stream to the 7th MSA is given by... 

Extraktions-anlage, /. extraction plant, -ap-parat, m. extraction apparatus, -dauer, /. time of extraction. -flUssigkeit, /. extraction liquid, liquid extract. -gef ss, n. extraction vessel, -hiilse, /. extraction shell or thimble. -kolben, m. extraction flask, -mittel, n. extracting agent, extraction solvent. -miihle,/. extraction mill, -rtickstand, m. extraction residue. 

The nature of the donor atoms in the chelating agent. Ligands which contain donor atoms of the soft-base type form their most stable complexes with the relatively small group of Class B metal ions (i.e. soft acids) and are thus more selective reagents. This is illustrated by the reagent diphenylthiocarbazone (dithizone) used for the solvent extraction of metal ions such as Pd2+, Ag+, Hg2+, Cu2+, Bi3+, Pb2+, and Zn2 +. ... 

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