Extraction process for

Table 4. Extractive Processes for the Separation of Benzene—Toluene—Xylene Mixture from Light Feedstocks ...

Extraction of C-8 Aromatics. The Japan Gas Chemical Co. developed an extraction process for the separation of -xylene [106-42-3] from its isomers using HF—BF as an extraction solvent and isomerization catalyst (235). The highly reactive solvent imposes its own restrictions but this approach is claimed to be economically superior to mote conventional separation processes (see Xylenes and ethylbenzene). 

Pentanedione is widely used in extraction processes for the separation and purification of metals because of its abiUty to form covalent metal chelates. It is also used as an intermediate in the production of heterocycHc substances and dyes, as a fuel additive (324), and in metal plating and resin modification. 

Liquid—Liquid Extraction. The tiquid—tiquid extraction process for the rare-earth separation was discovered by Fischer (14). Extraction of REE using an alcohol, ether, or ketone gives separation factors of up to 1.5. The selectivity of the distribution of two rare-earth elements, REI and RE2, between two nonmiscible tiquid phases is given by the ratio of the distribution coefficients DI and D2 ... 

Battery breaking technologies use wet classification to separate the components of cmshed batteries. Before cmshing, the sulfuric acid is drained from the batteries. The sulfuric acid is collected and stored for use at a later stage in the process, or it may be upgraded by a solvent extraction process for reuse in battery acid. 

A unique Hquid—Hquid extraction process for manufacturing boric acid from sodium borate brines has been operated at Seades Lake, Trona, California, by the North American Chemical Co. since 1962. Both potassium sulfate and sodium sulfate are produced as coproducts in this process. 

Selectivity for a single metal of a group is the basis of a solvent extraction process for the recovery of copper (qv) from low concentration ore leach solutions containing high levels of iron (qv) and other interfering metals (16). 

The value of K is one of the main parameters used to establish the minimum ratio of extraction solvent to feed solvent that can be employed in an extraction process. For exanmle, if the partition ratio K is 4, then a countercurrent extractor woula require 0.25 kg or more of extraction-solvent flow to remove all the solute from 1 kg of feed-solvent flow. 

Conversion of Lean Oil Absorption Process to Extraction Process for Conditioning Natural Gas, U.S. Patent 4.696,688, Sep. 29, 1987. 

In both cases, the extraction process includes washing (scrubbing) of the extract, a stage that is not shown separately. The organic phase that results from the stripping process is returned to the beginning of the extraction process for reuse as an extractant. 

FIG. 20-20 Idealized diagram of a supercritical fluid extraction process for solids. 

Inhibition of ferrochelatase in the heme pathway causes accumulation of protoporphyrin in erythrocytes (CDC 1985). Most protoporphyrin in erythrocytes (about 90%) exists as zinc protoporphyrin (ZnPP). This fraction is preferentially measured by hematofluorometers. Extraction methods measure all the protoporphyrin present, but strip the zinc from the ZnPP during the extraction process. For this reason,... 

LSBC has a long history of process development, scale-up and manufacturing experience, since its foundation back in 1987. The company has developed proprietary, industrial-scale extraction processes for the purification of proteins, peptides, and other biochemicals from plant biomass. It has also developed commercial methods for the extraction and purification of secreted plant proteins. 

Extraction processes for natural products including the decaffeination of coffee and tea and the isolation of nutraceuticals, flavors, and fragrances... 

AMAR A solvent extraction process for recovering copper. Used in approximately 50 installations worldwide in 1993. 

CAA [Cuprous ammonium acetate] A general process for separating alkenes, di-alkenes, and alkynes from each other by extraction of their cuprous complexes from aqueous cuprous ammonium acetate into an organic solvent. Exxon used it for separating C4 fractions containing low concentrations of butadiene. The liquid-liquid extraction processes for butadiene have all been replaced by extractive distillation processes. 

Clanex A solvent extraction process for converting solutions of the nitrates of actinides and lanthanides into their corresponding chlorides. The extractant is a solution of an aliphatic amine in diethylbenzene. 

EXOL N Also called EXOL N Extraction. A solvent extraction process for purifying feedstocks for making lubricating oil. The solvent is N-methyl pyrrolidone. Developed and licensed by Exxon Research Engineering Compary. Seventeen units had been installed by 1994. 

Mofex A liquid-liquid extraction process for removing aromatic hydrocarbons from hydrocarbon mixtures. The solvent is a monomethylformamide/water mixture, operated at 20 to 30°C, 0.1 to 0.4 bar. Developed by Leuna-Werke. 

Rectiflow A multi-stage, liquid-liquid extraction process for removing non-paraffinic components from lubricating oils. Furfural has been used as the solvent. Developed and used by the Shell Petroleum Company in the 1940s, subsequently abandoned. 

O Nickel and copper are both very important to the Ontario economy. Before they can be refined by electrolysis, they must be extracted from their ores. Both metals can be extracted from a sulfide ore, NiS or CU2S. The sulfide is roasted to form an oxide, and then the oxide is reduced to the metal. Research the extraction processes for both nickel and copper, and write balanced equations for the redox reactions involved. One product of each extraction process is sulfur dioxide. Research the environmental effects of this compound. Describe any steps taken to decrease these effects. 

Extraction process for arsenic and heavy metals AN - ammonium nitrate, KW = aqua regia (Konigswasser)... 

In simple experiments, particulate silica-supported CSPs having various cin-chonan carbamate selectors immobilized to the surface were employed in an enantioselective liquid-solid batch extraction process for the enantioselective enrichment of the weak binding enantiomer of amino acid derivatives in the liquid phase (methanol-0.1M ammonium acetate buffer pH 6) and the stronger binding enantiomer in the solid phase [64]. For example, when a CSP with the 6>-9-(tcrt-butylcarbamoyl)-6 -neopentoxy-cinchonidine selector was employed at an about 10-fold molar excess as related to the DNB-Leu selectand which was dissolved as a racemate in the liquid phase specified earlier, an enantiomeric excess of 89% could be measured in the supernatant after a single extraction step (i.e., a single equilibration step). This corresponds to an enantioselectivity factor of 17.7 (a-value in HPLC amounted to 31.7). Such a batch extraction method could serve as enrichment technique in hybrid processes such as in combination with, for example, crystallization. In the presented study, it was however used for screening of the enantiomer separation power of a series of CSPs. 

The initial requirement in the development of a solvent extraction process for the recovery or separation of metals from an aqueous solution is knowledge of the solution composition, pH, temperature, and flow rate. Both pH and temperature can be adjusted, within certain economic limits, before feeding to the solvent extraction circuit, but only in a few cases can the leaching or dissolution conditions be dictated by the extraction process. Consequently, no serious development work on the extraction process can be carried out before the leaching conditions or the type of feed solution are established. 

The formation of a third phase during the extraction of a metal by solvent (extractant and diluent) cannot be tolerated in liquid-liquid extraction processes for obvious reasons. Elimination of a third phase is usually accomplished by the addition of a modifier to the solvent, or by increasing the temperature of the system. 

In the optimization of the solvent extraction process for the recovery of copper using LIX 64N, Robinson [77] described the eost funetion in terms of the sum of the operating and capital costs. The operating eosts were taken as resulting from losses of eopper and solvent ... 

Ritcey, G. M. Ashbrook, A. W. Lucas, B. H. Development of a solvent extraction process for the separation of cobalt from nickel, presented at the Annual AIME Meeting, San Francisco, 1972. CIM Bull., January 1975. 

Although the use of such chemically assisted extraction procedures is unlikely to displace the established extraction processes for commercial extraction of penicillin, there are a number of other systems in biotechnology where ion pair formation is used (section 10.5). 

Pure isomers are often used as starting products for fine chemicals (e.g., different drugs). The separation of isomers entails great difficulties because they often have boiling points differing by only a fraction of a degree and they have closely similar solubilities in many solvents. Solvent extraction processes for the separation of isomers, therefore, have to rely more on chemical reactions than on nonspecific physical interactions between the solute and the solvent. 

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