Extraction reactive

The practical handling and design of a reactive solvent extraction process is given in appropriate handbooks [4—8], but a short review on the principles involved is provided here. Liquid ion exchangers are available as either anion, cation, or solvating exchangers. An example of an anion exchange is  

The quaternary R4-alkyl-substituted ammonium chlorides are commercially available, and can be stripped with a surplus of chloride, hydroxide, etc. thus, the solute is regenerated in the re-extraction or stripping step. The quaternary compound has the advantage of being able to be used in alkaline media compared to the frequently used ternary amines. Primary, secondary (both are water-soluble, less used) and tertiary amines are only stable in acidic aqueous media, as hydroxide destroys the ammonium complex  

nickel is extracted with a di(2-ethylhexyl) phosphoric acid in its H-form (HDEHP) and two protons are set free. This causes a pH-shift during extraction, which can be avoided if the ion exchanger is, for example, in the Na-form. Typical extraction isotherms are depicted in Fig. 10.2. At the indicated pH-value no nickel, but more than 80 % cobalt, can be extracted in one equilibrium stage. During cobalt 

An example of coordinative extraction with solvating agents is shown in Eq. (4). The difference with physical extraction is that the capacity and extraction power of the liquid neutral ion exchanger is much higher than with any bulk organic solvent (toluene, xylene, butanol, etc.) used in physical extraction. Alkyl-substituted 

Pregnant iquor Loaded organic Advanced electrolyte 

SA is an important industrial chemical with many potential applications as an important building block for valuable commodity and specialty chemicals and materials, and thus has been a key chemical of academic and industrial interest 

With many great advances made over the years, SA production is at the stage of commercialization. Several companies, such as Reverdia, Bioamber, Myriant, and Succinity, have initiated or are about to start the large-scale production of SA [1]. Furthermore, transformation of bio-based SA into other valuable chemicals such as 1,4-butanediol and tetrahydrofuran is being carried out by these companies, demonstrating that the microbial SA production is a successful example of industrial biotechnology. 

The authors declare that there is conflict of interest on M. succiniciproducens technology, as it is of commercial interest. 

Jansen, M.L. and van Gulik, W.M. (2014) Towards large scale fermentative production of succinic acid. Curr. Opin. Biotechnol, 30, 190-197. 

4 Zeikus,Jain, M., and Hankovan, P. (1999) Biotechnology of succinic acid production and markets for derived industrial products. AppL MicrohioL Biotechnol, 51, 545-552. 

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Completion of Esterification. Because the esterification of an alcohol and an organic acid involves a reversible equiUbrium, these reactions usually do not go to completion. Conversions approaching 100% can often be achieved by removing one of the products formed, either the ester or the water, provided the esterification reaction is equiUbrium limited and not rate limited. A variety of distillation methods can be appHed to afford ester and water product removal from the esterification reaction (see Distillation). Other methods such as reactive extraction and reverse osmosis can be used to remove the esterification products to maximize the reaction conversion (38). In general, esterifications are divided into three broad classes, depending on the volatility of the esters ... 

FIG. 13-79 Integrated reactive-extractive distillation column for the production of methyl acetate. 

FIG. 13-80 Reactive extracting distillation for methyl acetate production, (a) Composition profile, (b) Temperature profile. 

Supercritical fluid solvents have been tested for reactive extractions of liquid and gaseous fuels from heavy oils, coal, oil shale, and biomass. In some cases the solvent participates in the reactions, as in the hydrolysis of coal and heavy oils with water. Related applications include conversion of cellulose to glucose in water, dehgnincation of wood with ammonia, and liquefaction of lignin in water. 

Reverse-flow reactors Reactive distillation Reactive extraction Reactive crystalization Chromatographic reactors Periodic separating reactors Membrane reactors Reactive extrusion Reactive comminution Fuel cells... 

Removal of reaction products can shift the equilibrium, forcing the reaction to go to completion. This can be effected by evaporation of products from the reaction mixture (reactive distillations), extraction (including supercritical extraction) of products from the reaction mixture (reactive extractions), or membrane processes. Counter- and cocurrent operation also falls within this category. If the reaction is equilibrium-limited or inhibited by reaction products countercurrent operation outperforms cocurrent operation. 

For the purpose of the identification and quantification of additives (broadly defined) in polymeric materials extraction and dissolution methods are favoured (Sections 3.3-3.7). However, additives are also made accessible analytically by digestion of the sample matrix (cf. Section 8.2). Such wet chemical techniques, that remove the sample matrix first, are often limited to mg amounts because of pressure build-up in destruction vessels. Another reactive extraction approach to facilitate additive analysis is depolymerisation by acid hydrolysis or saponification, sometimes under pressure. This is then frequently followed by chemical methods such as titrimetry or photometry for final identification and quantification. 

In a typical example of reactive extraction a fatty acid ester was easily formed by adding a small amount of an alcohol to a fatty acid metal salt and extracting at 315 °C [647]. This method was applied to PP/calcium stearate and PP/zinc stearate containing pellets the presence of the fatty acid metal salts was confirmed by GC-MS. 

The previous chapters have demonstrated that liquid-liquid extraction is a mass transfer unit operation involving two liquid phases, the raffinate and the extract phase, which have very small mutual solubihty. Let us assume that the raffinate phase is wastewater from a coke plant polluted with phenol. To separate the phenol from the water, there must be close contact with the extract phase, toluene in this case. Water and toluene are not mutually soluble, but toluene is a better solvent for phenol and can extract it from water. Thus, toluene and phenol together are the extract phase. If the solvent reacts with the extracted substance during the extraction, the whole process is called reactive extraction. The reaction is usually used to alter the properties of inorganic cations and anions so they can be extracted from an aqueous solution into the nonpolar organic phase. The mechanisms for these reactions involve ion pah-formation, solvation of an ionic compound, or formation of covalent metal-extractant complexes (see Chapters 3 and 4). Often formation of these new species is a slow process and, in many cases, it is not possible to use columns for this type of extraction mixer-settlers are used instead (Chapter 8). 

In this paper an overview of the developments in liquid membrane extraction of cephalosporin antibiotics has been presented. The principle of reactive extraction via the so-called liquid-liquid ion exchange extraction mechanism can be exploited to develop liquid membrane processes for extraction of cephalosporin antibiotics. The mathematical models that have been used to simulate experimental data have been discussed. Emulsion liquid membrane and supported liquid membrane could provide high extraction flux for cephalosporins, but stability problems need to be fully resolved for process application. Non-dispersive extraction in hollow fib er membrane is likely to offer an attractive alternative in this respect. The applicability of the liquid membrane process has been discussed from process engineering and design considerations. 

Keywords. Cephalosporin antibiotics. Liquid membrane, Reactive extraction. Liquid-liquid ion extraction, Aliquat-336, HoUow-fiber membrane... 

It is apparent that for the reactive extraction to be effective, the cephalosporins should be in dissociated form which is maintained by selecting appropriate pH values depending on the dissociation constant (pK ) of the molecules. Table 1 gives the pK values for various cephalosporin molecules. 

Schugerl 115] has recently furnished a detail analysis of the reactive extraction of penicdlin-G and V and precursors like phenyl and phenoxy acetic acids. Thirty different amines have been studied for reactive extraction of penicillins 116] in various solvents such as butyl acetate, chloroform, di-isopropyl ether, kerosene, dioctyl ether, etc. Tertiary amines in n-butyl acetate were found to be advantageous because of their low reactivity with solvent but the distribution coefficients of their complexes are significantly lower than those of secondary amines. While using quaternary ammonium salts for ion-exchange extraction, re-extraction is difficult and very large amounts of anion (e.g.. Cl ) are needed to recover penicillins. The basic relationship for distribution coefficient and extraction kinetics have now been fairly developed for amine-penicillin systems. 

In order to develop the liquid membrane techniques, i.e., emulsion Hquid membrane (ELM), supported liquid membrane (SLM), non-dispersive extraction in hollow fiber membrane (HFM), etc., for practical processes, it is necessary to generate data on equilibrium and kinetics of reactive extraction. Furthermore, a prior demonstration of the phenomena of facilitated transport in a simple liquid membrane system, the so-called bulk liquid membrane (BLM), is thought to be effective. Since discovery by Li [28], the liquid membrane technique has been extensively studied for the separation of metal ion, amino acid, and carboxyHc acid, etc., from dilute aqueous solutions [29]. 

Reactive extraction studied for cephalosporins and penicillins using different carriers and solvents can now be applied in LM for their separation from practical point of view [50-52]. In a typical membrane formulation of an oil phase... 

The permeation of cephalosporin antibiotics in an SLM system under reactive extraction condition can be considered a coupled transport phenomenon which can describe metal ion permeation behavior. Various steps are involved in the coupled transport in the SLM system ... 

Martak, ]., Schlosser, S., Phosphonium ionic liquids as new, reactive extractants of lactic acid, Chem. Pap., 60, 395-398, 2006. 

Reactive extraction of lignin from red spruce has been studied using supercritical methylamine and methyla-mine-nitrous oxide binary mixtures. The wood residues and precipitated fractions after extractions have been characterized by chemical and spectroscopic procedures. 

Reactive extraction processes involve simultaneous reaction and liquid-liquid phase separation and can be effectively utilized to obtain significant improvements in yields of desired products and selectivities to desired products in multireaction systems, thereby reducing recycle flows and waste formation. The combination of... 

Reactive distillation Membrane-based reactive separations Reactive adsorption Reactive absorption Reactive extraction Reactive crystallization... 

Similar to reactive adsorption, the reactive extraction can be applied primarily in multireaction systems, for improvement in yields and selectivities to desired products. The combination of reaction with liquid-liquid extraction can also be used... 

TABLE 4 Some Processes Studied in Reactive Extraction Systems... 

Crandall JW, Grimm RC. Separation of organic acids from the products of partial oxidation of paraffins by reactive extraction with amines. U.S. Patent 3,541,121, Union Carbide Corp., 1970. 

Bart HJ. Reactive Extraction. Berlin Springer-Verlag, 2001. 

Verhoeven W, Sluyts D, Denecker G, van Osselaer T, Hinz J, Vaes J, van Herck W, de Vos S. Treatment of phenolic wastewaters from manufacture of polycarbonates, bisphenols or diphenyl carbonate by reactive extraction. DE 19510063, Bayer Antwerpen N.V., 1996. 

Kueke F. Procedure for the reactive extraction of chromium-containing substances from aqueous feed solutions. DE 19943232, 2001. 

Brugel EG. Production of cyclic ester oligomers from linear polyesters by reactive extraction. WO 0268496, E.I. Du Pont de Nemours and Co., 2002. 

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