Solvent extraction water

The final step is the purification of phenol by solvent extraction (water and benzene) and distillation. 

There are of course liquid-liquid equilibria between hydrocarbons and substances other than water. In practice these equilibria are used in solvent extraction processes. The solvents most commonly used are listed as follows ... 

To ensure disposal water quality is in line with regulatory requirements (usually 40 ppm), the oil content in water is monitored by solvent extraction and infrared spectroscopy. The specification of 40 ppm refers to an oil in water content typically averaged over a one month period. 

Iron(III) chloride forms numerous addition compounds, especially with organic molecules which contain donor atoms, for example ethers, alcohols, aldehydes, ketones and amines. Anhydrous iron(III) chloride is soluble in, for example, ether, and can be extracted into this solvent from water the extraction is more effective in presence of chloride ion. Of other iron(III) halides, iron(III) bromide and iron(III) iodide decompose rather readily into the +2 halide and halogen. 

Anhydrous Acetic Acid. In the manufacture of acetic acid by direct oxidation of a petroleum-based feedstock, solvent extraction has been used to separate acetic acid [64-19-7] from the aqueous reaction Hquor containing significant quantities of formic and propionic acids. Isoamyl acetate [123-92-2] is used as solvent to extract nearly all the acetic acid, and some water, from the aqueous feed (236). The extract is then dehydrated by azeotropic distillation using isoamyl acetate as water entrainer (see DISTILLATION, AZEOTROPIC AND EXTRACTIVE). It is claimed that the extraction step in this process affords substantial savings in plant capital investment and operating cost (see Acetic acid and derivatives). A detailed description of various extraction processes is available (237). 

Preparation of soil—sediment of water samples for herbicide analysis generally has consisted of solvent extraction of the sample, followed by cleanup of the extract through Uquid—Uquid or column chromatography, and finally, concentration through evaporation (285). This complex but necessary series of procedures is time-consuming and is responsible for the high cost of herbicide analyses. The advent of soUd-phase extraction techniques in which the sample is simultaneously cleaned up and concentrated has condensed these steps and thus gready simplified sample preparation (286). 

Manufacture. Cyanoacetic acid and cyanoacetates are iadustrially produced by the same route as the malonates starting from a sodium chloroacetate solution via a sodium cyanoacetate solution. Cyanoacetic acid is obtained by acidification of the sodium cyanoacetate solution followed by organic solvent extraction and evaporation. Cyanoacetates are obtained by acidification of the sodium cyanoacetate solution and subsequent esterification with the water formed being distilled off. Other processes reported ia the Hterature iavolve the oxidation of partially oxidized propionittile [107-12-0] (59). Higher esters of cyanoacetic acid are usually made through transesterification of methyl cyanoacetate ia the presence of alumiaiumisopropoxide [555-31-7] as a catalyst (60). 

Solvent extraction techniques are useful in the quantitative analysis of niobium. The fluoro complexes are amenable to extraction by a wide variety of ketones. Some of the water-insoluble complexes with organic precipitants are extractable by organic solvents and colorimetry is performed on the extract. An example is the extraction of the niobium—oxine complex with chloroform (41). The extraction of the niobium—pyrocatechol violet complex with tridodecylethylammonium bromide and the extraction of niobium—pyrocatechol—sparteine complex with chloroform are examples of extractions of water-soluble complexes. Colorimetry is performed on the extract (42,43). Colorimetry may also be performed directly on the water-soluble complex, eg, using ascorbic acid and 5-nitrosahcyhc acid (44,45). 

Turpentine Oil. The world s largest-volume essential oil, turpentine [8006-64-2] is produced ia many parts of the world. Various species of piaes and balsamiferous woods are used, and several different methods are appHed to obtain the oils. Types of turpentines include dry-distiUed wood turpentine from dry distillation of the chopped woods and roots of pines steam-distilled wood turpentine which is steam-distilled from pine wood or from solvent extracts of the wood and sulfate turpentine, which is a by-product of the production of sulfate ceUulose. From a perfumery standpoint, steam-distilled wood turpentine is the only important turpentine oil. It is rectified to yield pine oil, yellow or white as well as wood spirits of turpentine. Steam-distilled turpentine oil is a water-white mobile Hquid with a refreshing warm-balsamic odor. American turpentine oil contains 25—35% P-pinene (22) and about 50% a-pinene (44). European and East Indian turpentines are rich in a-pinene (44) withHtfle P-pinene (22), and thus are exceUent raw materials... 

The purified acid is recovered from the loaded organic stream by contacting with water in another countercurrent extraction step. In place of water, an aqueous alkafl can be used to recover a purified phosphate salt solution. A small portion of the purified acid is typically used in a backwashing operation to contact the loaded organic phase and to improve the purity of the extract phase prior to recovery of the purified acid. Depending on the miscibility of the solvent with the acid, the purified acid and the raffinate may be stripped of residual solvent which is recycled to the extraction loop. The purified acid can be treated for removal of residual organic impurities, stripped of fluoride to low (10 ppm) levels, and concentrated to the desired P2 s Many variations of this basic scheme have been developed to improve the extraction of phosphate and rejection of impurities to the raffinate stream, and numerous patents have been granted on solvent extraction processes. 

Plasticizer can also be extracted from PVC by a range of solvents including water. The aggressiveness of a particular solvent depends on its molecular size and its compatibiUty with both the plasticizer and PVC. Water extracts plasticizer very slowly, oils are slightly mote aggressive, and low molecular weight solvents are the most aggressive. 

The principle of solvent extraction in refining is as follows when a dilute aqueous metal solution is contacted with a suitable extractant, often an amine or oxime, dissolved in a water-immiscible organic solvent, the metal ion is complexed by the extractant and becomes preferentially soluble in the organic phase. The organic and aqueous phases are then separated. By adding another aqueous component, the metal ions can be stripped back into the aqueous phase and hence recovered. Upon the identification of suitable extractants, and using a multistage process, solvent extraction can be used to extract individual metals from a mixture. 

The mixture is kept for 3 hours at 105°C after the oxide addition is complete. By this time, the pressure should become constant. The mixture is then cooled to 50°C and discharged into a nitrogen-filled botde. The catalyst is removed by absorbent (magnesium siUcate) treatment followed by filtration or solvent extraction with hexane. In the laboratory, solvent extraction is convenient and effective, since polyethers with a molecular weight above about 700 are insoluble in water. Equal volumes of polyether, water, and hexane are combined and shaken in a separatory funnel. The top layer (polyether and hexane) is stripped free of hexane and residual water. The hydroxyl number, water, unsaturation value, and residual catalyst are determined by standard titration methods. 

Polyethers prepared from propylene oxide are soluble in most organic solvents. The products with the highest hydroxyl number (lowest molecular weight) are soluble in water, not in nonpolar solvents such as hexane. The solubihty of 3000 molecular weight triols is high enough in solvents such as toluene, hexane, and methylene chloride that the triols can be purified by a solvent extraction process. 

The batch and fed-batch procedures are used for most commercial antibiotic fermentations. A typical batch fermentor may hold over 150,000 Hters. When a maximum yield of antibiotic is obtained, the fermentation broth is processed by purification procedures tailored for the specific antibiotic being produced. Nonpolar antibiotics are usually purified by solvent extraction procedures water-soluble compounds are commonly purified by ion-exchange methods. Chromatography procedures can readily provide high quaHty material, but for economic reasons chromatography steps are avoided if possible. 

The heavy metal salts, ia contrast to the alkah metal salts, have lower melting points and are more soluble ia organic solvents, eg, methylene chloride, chloroform, tetrahydrofiiran, and benzene. They are slightly soluble ia water, alcohol, ahphatic hydrocarbons, and ethyl ether (18). Their thermal decompositions have been extensively studied by dta and tga (thermal gravimetric analysis) methods. They decompose to the metal sulfides and gaseous products, which are primarily carbonyl sulfide and carbon disulfide ia varying ratios. In some cases, the dialkyl xanthate forms. Solvent extraction studies of a large number of elements as their xanthate salts have been reported (19). 

Polyethers are usually found in both the filtrate and the mycelial fraction, but in high yielding fermentations they are mosdy in the mycelium because of their low water-solubiUty (162). The high lipophilicity of both the free acid and the salt forms of the polyether antibiotics lends these compounds to efficient organic solvent extraction and chromatography (qv) on adsorbents such as siUca gel and alumina. Many of the production procedures utilize the separation of the mycelium followed by extraction using solvents such as methanol or acetone. A number of the polyethers can be readily crystallized, either as the free acid or as the sodium or potassium salt, after only minimal purification. 

A beryUium concentrate is produced from the leach solution by the counter-current solvent extraction process (10). Kerosene [8008-20-6] containing di(2-ethylhexyl)phosphate [298-07-7] is the water-immiscible beryUium extractant. The slow extraction of beryUium at room temperature is accelerated by warming. The raffinate from the solvent extraction contains most of the aluminum and aU of the magnesium contained in the leach solution. 

Pharmaceuticals. Pharmaceuticals account for 6% of the Hquid-phase activated carbon consumption (74). Many antibiotics, vitarnins, and steroids are isolated from fermentation broths by adsorption onto carbon foUowed by solvent extraction and distillation (82). Other uses in pharmaceutical production include process water purification and removal of impurities from intravenous solutions prior to packaging (83). 

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