Water insoluble solvents

For the purpose of accelerating the scouring process, wetting agents are sometimes used in conjunction with high boiling solvents (cyclohexanol, methylcyclohexanol, tetrahydronaphthalene, decahydronaphthalene etc.). The function of the solvent is to dissolve more insoluble fats and waxes and that of the detergent to emulsify the solvent and waxes. 

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In the separations (2) and (3) above, it is often advisable to dissolve the original mixture in a water-insoluble solvent. Select a solvent which will dissolve the entire mixture, and then shake the solution with either (i) dil. NaOH or (ii) dil. HCl. Separate the aqueous layer, and to it add either (i) dil. HCl or (ii) dil. NaOH to liberate the organic acid or the organic base, as the case may be. The non-aqueous layer now contains the neutral component. Reextract this layer with either (i) dil. NaOH or (ii) dil. HCl to ensure removal of traces of the non-neutral component. 

When the distribution coefficient for the desired solute from aqueous solutions into even the best of solvents is unfavourable it may become attractive to superimpose reaction. Consider the. separation of citric acid from aqueous solutions, for which physical extraction is unattractive. Here we can use a bulky tertiary amine, e.g. tri-2-ethylhexylamine, which has a very low solubility in water, and dissolve it in a suitable, water-insoluble solvent this will... 

Anon., Univ. Safety Assoc., Safety Newsletter, 1982-1984 A solution of the chloride (120 ml) in toluene (750 ml) was treated (apparently without effective stirring) with excess sodium bicarbonate solution to destroy it. When reaction had ceased, the organic layer was poured into a waste solvent drum. Vigorous evolution of sulfur dioxide and hydrogen chloride then ensued from reaction with ethanol (toluene-soluble) in the waste drum. For destruction of solutions of sulfinyl chloride in water-insoluble solvents, extremely good agitation is necessary to ensure proper contact with a basic reagent. Ammonia is more soluble in toluene than is water, so ammonia solution should be used after bicarbonate treatment to ensure complete destruction. 

Aqueous chromic acid acting on a solution of the alcohol in an inert water insoluble solvent [14] is a well known oxidation procedure giving the carbonyl compound. A stoichiometric amount of reagent is required. The aqueous solution of chromiura(lii) residues can be electrochemically oxidised to the chromium(vr) state [15], however few studies have been made on coupling this process with the excell the oxidation of alcohols. 

In a typical experiment, a small volume of an insoluble surface-active material (dissolved in a water-insoluble solvent such as benzene) is placed atop a clean water surface. As the solvent evaporates away, a film remains and the moving barrier can be adjusted so that the surface film exerts pressure on the mica float. A calibrated torsion balance is used to measure the force that the film exerts on the float. That force divided by the length of the float is the force per unit length or the surface pressure. For studies of lipolysis kinetics , a Langmuir trough can be constructed so that one can measure lipase action under first-order and zero-order conditions. 

The use of extraction as we have described it to remove pollutants from groundwater would be unworkable. The concentrations are so low that large quantities of water-insoluble solvents would have to be used and recovered. Inasmuch as the recovery of the solvents would be inexact, more pollutants would doubtless be released into the environment than would be removed. We may have found a solution to this puzzle by using a solvent that does not have to be recovered in the typical sense of the word. 

As diazonium tetrafluoroborates are more soluble in strongly acidic media, the precipitation of the diazonium tetrafluoroborate from an auxiliary diazonium salt and alkaline tetrafluoroborate is preferred when the diazonium tetrafluoroborate is thought to be too soluble an increase of the ionic strength tends to decrease its solubility.3-129 However, some alkaline chloride can co-precipitate with the diazonium tetrafluoroborate. Consequently, the diazonium tetrafluoroborate yields can be a little optimistic and some chlorinated aromatics can be produced together with fluorinated aromatics during the dediazoniation step.3,171 To prevent such contamination, the diazonium tetrafluoroborate is washed with the minimum amount of chilled water, then with another polar solvent, such as an alcohol, and finally with a water-insoluble solvent, such as diethyl ether. When their decomposition points are not too low, diazonium tetrafluoroborates can also be purified by rccrystallization (in water or acetic acid) or by dissolution in acetone then salting out with diethyl ether.3... 

Another important group of anisotropic composite membranes is formed by solution-coating a thin (0.5-2.0 xm) selective layer on a suitable microporous support. Membranes of this type were first prepared by Ward, Browall, and others at General Electric [52] and by Forester and Francis at North Star Research [17,53] using a type of Langmuir trough system. In this system, a dilute polymer solution in a volatile water-insoluble solvent is spread over the surface of a water-filled trough. 

A slurry of sodium bicarbonate comprising 39.8 g sodium bicarbonate and 254 ml water was placed in an autoclave. 96.3 g hexadecyl bromide and 635 ml acetone were then added. The autoclave was sealed and while stirring (590 r.p.m.) it was heated to a temperature of 218°C over a period of 1 hour 15 min. The temperature was maintained at 218-220°C for an additional hour. At the end of the reaction the autoclave was cooled to about 50°C, that is, to a temperature at which the alcohol remains molten. The autoclave was then rinsed with acetone and 1 N hydrochloric acid add to neutralize the sodium bicarbonate. The reaction mixture was diluted with an equivalent volume of water and then extracted with n-pentane. (Other suitable water insoluble solvents such as benzene, carbon tetrachloride, chloroform, petroleum ether and the like can be used for extraction). The pentane extract was washed with water and then dried over magnesium sulfate. The dried solution was filtered and evaporated. The residue was melted and a vacuum applied to remove the last traces of pentane. On distillation a yield of 94.8% of the theoretical yield white crystals of hexadecanol was recovered M.P. 49°C, B.P. 344°C, nD79 = 1.4283. 

Su oemulsions are defined as a mixture of a dispersed solid phase and an emulsified oil phase in water as the continuous or bulk phase. The solid phase is a solid, water insoluble active ingredient, the oil phase a liquid pesticide in pure form or dissolved in a water insoluble solvent. The oil phase can sometimes also be an oil or adjuvant. Suspoemulsions are a relatively new formulation type as becomes evident by the fact that a FAO specification was established only as late as 1997. At the same time specific evaluation methods were officially published (CIPAC MT 180) [2]. 

The water-insoluble solvents used in commercially available solubilized oral formulations include oleic acid, DL-a-tocopherol (Vitamin E), the long-chain triglycerides peanut oil, corn oil, soybean oil, sesame oil, olive oil, peppermint oil, and castor oil, the medium-chain triglycerides derived from coconut oil and palm seed oil, and the short-chain triglyceride triacetin. 

Sodium dichromate, Na2Cr207, is applied not only in solutions in sulfuric acid but also in solutions in perchloric acid [620, 621], acetic acid [622, 623, 624, 625, 626, 627, 628], benzene, and dimethyl sulfoxide [629], In the presence of tetrabutylammonium bisulfate, dichloromethane, used as a water-insoluble solvent, extracts the product from the aqueous phase (phase transfer) [630]. 

Currently, the use of water insoluble solvents such as ethyl acetate that do not require partition is preferred. Unfortunately, using ethyl acetate, lower recoveries are observed for the most polar pesticides. If the raw extract is saturated with sodium sulphate, satisfying recoveries are observed for methamidophos, acephate and omethoate (Holland and Malcolm, 1992). 

This sample preparation method involves steam distillation of the volatile organic components of a sample followed by preconcentration by LEE using a water-insoluble solvent. SDE served as unique clean-up and preconcentration step before derivatization, in the GC-MS determination of polycyclic aromatic hydrocarbons, phenols and aromatic amines in particulate phase mainstream cigarette smoke . Preconcentration by the SDE... 

Several organic solvents were investigated, including dichloromethane, chloroform, ethyl acetate, acetone, methylethylketone, tetrahydrofuran, acetonitrile, and mixtures thereof, but only water-insoluble solvents were suited for dissolving polymer and phospholipid in high concentrations and forming spherical particles in good yield. 

Phase-Transfer Catalysis. Since the efficiency of the reaction requires that bisphenoi A be used in the form of water-soluble phenolate anions, while phosgene must be dissolved in a chemically inert and hence water-insoluble solvent, the desired reaction would have to depend on the diffusion rate of the two reactants to the interface between the immiscible solvents. The area of the interface can be increased by vigorous stirring of the two-phase reaction mixture, but a more efficient way to accelerate the process is to induce one of the reactants to migrate into a phase that is not particularly receptive to it. In this example, the sodium phenolate ions are in equilibrium with a phase-transfer catalyst such as tetra-n-butylammonium chloride, and while one of the products of the equilibrium (sodium chloride) remains in the aqueous phase, the other products of the equilibrium (the BPA anion-tetra-rc-butylammonium cation ion pairs) are of sufficiently covalent character to migrate into the nonaqueous phase where they encounter phosgene and the reaction takes place. 

It is usually unnecessary to isolate such hydrazones during the working up the mixture is partitioned between water and a water-insoluble solvent such as ether. The hydrazones then remain in the aqueous phase, and the other organic substances are removed in the organic phase. The carbonyl components are finally regenerated from the aqueous hydrazone phase by acid hydrolysis. Considerable fractionation of mixed carbonyl compounds can be achieved by varying the reaction conditions, notably the temperature or pH, of either the condensation or the hydrolysis. Acid-sensitive carbonyl compounds, e.g., citral, may be isolated by exchange from the hydrazone by an excess of formaldehyde.932... 

Peroxides may be removed by treating the solvents with a reducing agent such as ferrous sulfate or sodium bisulfite. About 1 L of water-insoluble solvent is treated with 10 g of hydrated ferrous sulfate in 25 mL of 50% sulfuric acid in a separatory funnel and shaken vigorously for a few minutes. Other procedures for removing peroxides involve... 

Water-insoluble solvents. Most alkaloids are commonly present in the plant as organic salts. In order to solubilize the alkaloids the crude biomass extract is made basic by the addition of, for example, potassium hydroxide, potassium carbonate, or ammonia. At the resulting high pH the alkaloids are mainly present in their neutral form. The neutral alkaloids are then easily extracted from the aqueous phase with a water-insoluble organic solvent, for example, dichloromethane or chloroform. 

Today no chemical additives are used to modify the viscosity of the organic material of natural origin (wood pitch) to reduce deposition. Water-insoluble solvents, that would reduce the viscosity, can conceivably be used reducing the viscosity of the resin. The use of kerosene for pitch control, a method used half a century ago, worked by this mechanism. 

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