Organic solvents mixing

Soil samples are generally extracted with one or more organic solvents mixed with up to 10% (v/v) water. A wide variety of solvents is used for extraction, the choice... 

Various other biphasic solutions to the separation problem are considered in other chapters of this book, but an especially attractive alternative was introduced by Horvath and co-workers in 1994.[1] He coined the term catalysis in the fluorous biphase and the process uses the temperature dependent miscibility of fluorinated solvents (organic solvents in which most or all of the hydrogen atoms have been replaced by fluorine atoms) with normal organic solvents, to provide a possible answer to the biphasic hydroformylation of long-chain alkenes. At temperatures close to the operating temperature of many catalytic reactions (60-120°C), the fluorous and organic solvents mix, but at temperatures near ambient they phase separate cleanly. Since that time, many other reactions have been demonstrated under fluorous biphasic conditions and these form the basis of this chapter. The subject has been comprehensively reviewed, [2-6] so this chapter gives an overview and finishes with some process considerations. 

Clear and colorless liquid with a pleasant odor bp 56.5°C (133°F) density 1.5167 at 25°C (77°F) soluble in most organic solvents, mixes with oils and fats, insoluble in water. 

EKC separations of aliphatic amines include electrolyte systems composed of several surfactants (SDS, cholate, Brij 35 ) modified by certain additives (urea, neutral CDs, organic solvents ), mixed CDs, and more unusual secondary phases [resorcarene-octacarboxylic acid, calixarene," poly(sodium 4-styrenesulfonate), PSSS ]. Derivatization is performed when UV (o-phthaldialdehyde, OPA, as derivatizing agents) or LIF detection [3-(2-furoyl)quinoline-2-carboxaldehyde, 5-(4,6-dichloro-s-triazin-2-ylamino)fluorescein (DTAF) as labeling agents] is designed. 

Stationary phases for hydrophilic interaction chromatography, such as the amino and ZIC-HILIC phases in Table 22-3, are strongly polar. They are thought to be coated with a thin layer of water inside the column. Polar solutes are retained by the polar bonded phase and by the thin aqueous layer. The mobile phase typically contains (25-97 vol%) CH3CN or other polar organic solvent mixed with aqueous buffer. The higher the concentration of organic solvent, the less soluble is the polar solute in the mobile phase. 

In the extractor (E) acetic acid, furfural, formic acid, and methanol are extracted from the organics through a polar organic solvent mix. The extractant is a mixture of tri-n-octylphosphineoxide (CAS 78-50-2) and imdecane (CAS 1120-21-4), which does not dissolve in the condensate. The solvent extraction step is able to remove 85—90% of the organic compotmds.The aqueous raffinate is purified and can be used as a fresh water substitute in the pulp mill. The solvent extract is transferred into a flash vessel where most of the water is removed. Afterward, the raw product is removed from the solvent extract by a stripping distillation (S). While the solvent is supplied to the extractor again, the acetic acid and furfural-rich overhead stream (raw product) is forwarded to a number of rectifying columns in which by-products are removed and the final product is purified to the required quality. ... 

To improve dissolution of THC and its metabolites during reconstitution 100% solvent (methanol or acetonitrile) should be used. If this is not possible, first add the organic solvent, mix thoroughly, and then add the aqueous phase. 

Hence dinitrogen tetroxide (sometimes mixed with an organic solvent) can be used to prepare anhydrous metal nitrates (many heavy metal nitrates are hydrated when prepared in aqueous solution, and they cannot be dehydrated without decomposition). 

In this experiment the effect of a mixed aqueous-organic solvent on the color transition range of common indicators is investigated. One goal of the experiment is to design an appropriate titrimetric method for analyzing sparingly soluble acids and bases. 

Selectivity. Solvent selectivity is intimately linked to the purity of the recovered extract, and obtaining a purer extract can reduce the number and cost of subsequent separation and purification operations. In aqueous extractions pH gives only limited control over selectivity greater control can be exercised using organic solvents. Use of mixed solvents, for example short-chain alcohols admixed with water to give a wide range of compositions, can be beneficial in this respect (6). 

Ce(IV) extracts more readily iato organic solvents than do the trivalent Ln(III) ions providing a route to 99% and higher purity cerium compounds. Any Ce(III) content of mixed lanthanide aqueous systems can be oxidi2ed to Ce(IV) and the resultiag solutioa, eg, of nitrates, contacted with an organic extractant such as tributyl phosphate dissolved in kerosene. The Ce(IV) preferentially transfers into the organic phase. In a separate step the cerium can be recovered by reduction to Ce(III) followed by extraction back into the aqueous phase. Cerium is then precipitated and calcined to produce the oxide. 

Cobalt(Il) dicobalt(Ill) tetroxide [1308-06-17, Co O, is a black cubic crystalline material containing about 72% cobalt. It is prepared by oxidation of cobalt metal at temperatures below 900°C or by pyrolysis in air of cobalt salts, usually the nitrate or chloride. The mixed valence oxide is insoluble in water and organic solvents and only partially soluble in mineral acids. Complete solubiUty can be effected by dissolution in acids under reducing conditions. It is used in enamels, semiconductors, and grinding wheels. Both oxides adsorb molecular oxygen at room temperatures. 

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