Insoluble liquids

When the liquids A and B are insoluble over the range of solute concentrations encountered, the stage computation is done more simply in terms of mass flow rates of A (A mass/time) and B (fl mass/time) and the mass ratios, defined here as  

For the special case where the equilibrium curve is of constant slope m = y lx, a special form of Kremser equations applies  

Equation (7-18) is valid for EF 1. If the Murphree stage efficiency expressed in terms of extract compositions, EM , is constant, then the overall efficiency for the cascade is given by 

A solution of nicotine (C) in water (A) is to be extracted at 293 K using pure kerosene (B) as the solvent. Water and kerosene are essentially insoluble at this temperature. The feed is 1000 kg/h of a solution containing 1.0 wt% nicotine. The exiting raffinate stream should contain 0.1 wt% nicotine. Determine  

The feed to the process flows at the rate of 1000 kg/h and is 99% water. Therefore, A = 990 kg water/h. From equation (7-17), 

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B). Many nitriles when treated with hydrogen peroxide in warm alkaline solution undergo hydrolysis to amides which can thus be readily obtained in high yield. Insoluble liquid nitriles can be treated directly in the aqueous suspension, but for insoluble solid nitriles the addition of a suitable organic solvent to give a complete solution may be desirable, although the completion of the hydrolysis may not then be so readily detected. 

Esters of sulphuric acid. These compounds are generally water insoluble liquids and are saponified by boiling with water or dilute alkali to the corresponding alcohols and sulphuric acid ... 

Heat may be transferred between two insoluble liquids in countercurrent flowthrough an extractor, and the performance can be evaluated in the same general manner as in mass transfer (Fig. 15-20). For a differential contactor the number of overall heat-transfer units based on the hot phase can be derived from the same equations used for the number of mass-transfer units based on the feed (raffinate) phase [Eq. (15-36)]. 

Separation of components in solution. This includes the ordi-naiy objectives of liquid extrac tion, in which the constituents of a solution are separated by causing their unequal distribution between two insoluble liquids, the washing of a liquid with another to remove small... 

Alkenes — Also known as olefins, and denoted as C H2 the compounds are unsaturated hydrocarbons with a single carbon-to-carbon double bond per molecule. The alkenes are very similar to the alkanes in boiling point, specific gravity, and other physical characteristics. Like alkanes, alkenes are at most only weakly polar. Alkenes are insoluble in water but quite soluble in nonpolar solvents like benzene. Because alkenes are mostly insoluble liquids that are lighter than water and flammable as well, water is not used to suppress fires involving these materials. Because of the double bond, alkenes are more reactive than alkanes. 

If two insoluble liquids are heated, each is unaffected by the presence of the other and vaporizes to an extent determined only by its own nature. Such a mixture always boils at a temperature lower than is true for either substance alone. This effect may be applied to substances that would be damaged by overheating if distilled in the usual fashion. Substances can also be distilled at temperatures below their normal boiling points by partially evacuating the still. The greater the vacuum, the lower the distillation temperature. 

Separations based upon differences in the chemical properties of the components. Thus a mixture of toluene and aniline may be separated by extraction with dilute hydrochloric acid the aniline passes into the aqueous layer in the form of the salt, aniline hydrochloride, and may be recovered by neutralisation. Similarly, a mixture of phenol and toluene may be separated by treatment with dilute sodium hydroxide. The above examples are, of course, simple apphcations of the fact that the various components fall into different solubility groups (compare Section XI,5). Another example is the separation of a mixture of di-n-butyl ether and chlorobenzene concentrated sulphuric acid dissolves only the n-butyl other and it may be recovered from solution by dilution with water. With some classes of compounds, e.g., unsaturated com-poimds, concentrated sulphuric acid leads to polymerisation, sulphona-tion, etc., so that the original component cannot be recovered unchanged this solvent, therefore, possesses hmited apph cation. Phenols may be separated from acids (for example, o-cresol from benzoic acid) by a c ute solution of sodium bicarbonate the weakly acidic phenols (and also enols) are not converted into salts by this reagent and may be removed by ether extraction or by other means the acids pass into solution as the sodium salts and may be recovered after acidification. Aldehydes, e.g., benzaldehyde, may be separated from liquid hydrocarbons and other neutral, water-insoluble liquid compounds by shal g with a solution of sodium bisulphite the iddehyde forms a solid bisulphite compound, which may be filtered off and decomposed with dilute acid or with sodium bicarbonate solution in order to recover the aldehyde. 

G. C. Frye and J. C. Berg. Mechanisms for the synergistic antifoam action by hydrophobic solid particles in insoluble liquids. J Colloid Interface Sci, 130(1) 54—59, June 1989. 

An insoluble liquid or gas will separate from water, resulting in immiscible-phase separation. The behavior of nonaqueous-phase liquids (NAPLs) that may be lighter (LNAPLs) or denser (DNAPLs)... 

A bucket containing 25% sodium hydroxide solution was used to catch and neutralise bromine dripping from a leak. Lack of stirring allowed a layer of unreacted bromine to form below the alkali. Many hours later, a violent eruption occurred when the layers were disturbed dining disposal operations. Continuous stirring is essential to prevent stratification of slowly reacting mutually insoluble liquids, especially of such differing densities. 

The vegetable soup preparation is a solid-liquid extraction. So is coffee making. You extract some component(s) of a solid directly into the solvent. You might do a solid-liquid extraction in lab as a separate experiment liquid - liquid extractions are routine. They are so common that if you are told to do an extraction or a washing, it is assumed, you will use two liquids—two INSOLUBLE liquids—and a separatory funnel. The separatory funnel, called a sep funnel by those in the know, is a special funnel that you can separate liquids in. You might look at the section on separatory funnels (later in this chapter) right now, then come back later. 

Two insoluble liquids in a separatory funnel will form layers one liquid will float on top of the other. You usually have compounds dissolved in these layers, and either the compound you want is extracted from one to the other, or junk you don t want is washed from one layer to the other. 

You must have two insoluble liquid layers to perform an extraction. 

By way of example, let s say you have an aqueous solution of oxalic acid, and you need to isolate it from the water by doing an extraction. In your handbook, you find some solubilities of oxalic acid as follows 9.5g/100g in water 23.7g/100g in ethanol 16.9g/100g in diethyl ether. Based upon the solubilities, you decide to extract into ethanol from water, forgetting for the moment that ethanol is soluble in water, and you must have two insoluble liquids to carry out an extraction. Chagrined, you choose diethyl ether. 

AKDs are waxy, water-insoluble solids with melting points around 50 °C, and ASAs are viscous water-insoluble liquids at room temperature. It is necessary to prepare them as stabilised emulsions by dispersion in a cationic polymer (normally cationic starch). Small amounts of retention aid and surfactants may also be present. Particle size distributions are around 1 fim, and addition levels around 0.1% (of pure AKD or ASA) by weight of dry fibre. This is an order of magnitude lower than the amount of rosin used in rosin-alum sizing (1-2%). Emulsions of AKD are more hydrolytically stable than ASA, and the latter must be emulsified on-site and used within a few hours. 

Mixtures of hydrazine and other compounds form liquid explosives which have been described. A study of the detonability of binary and ternary mixtures of nitromethane—hydrazine-methanol showed that N2 H, sensitizes nitromethane and nitromethane-methanol mixtures to detonation (Ref 29). From 2-10% N2H, and 90-98% lower molecular weight nitroparaffins are claimed to be a water insoluble liquid explosive (Ref 22). Mixtures of hydrazine, ammonium nitrate and aluminum have been patented as explosive compositions with high air blast effects (Ref 32). 

Alkenes are insoluble in water but quite soluble in nonpolar solvents like benzene. Because alkenes are mostly insoluble liquids that are lighter than water and flammable as well, water is not used to suppress fires involving these materials. Because of the double bond, alkenes are more reactive than alkanes. 

Emulsifiers and wetting agents (detergents and/or surfactants) are composed of anionic, cationic, or nonionic detergents, metal soaps, polyamines, and tall oils or fatty acids [28]. They facilitate the formation of a stable dispersion of insoluble liquids in water (invert-emulsion). Wetting agents are used to ensure that the solids in mud... 

The butane isomerization process developed by the Universal Oil Products Co. is shown in Figure 4. In this process (3), the feed is maintained essentially in the liquid phase under pressure. Part of the feed is by-passed through a saturator, where it dissolves aluminum chloride. The feed later picks up hydrogen chloride and passes through the reactor, which is packed with quartz chips. Some insoluble liquid complex is formed, and this adheres to the quartz chips. The aluminum chloride in the feed is preferentially taken up by the complex, which thus maintains an active catalyst bed. The complex slowly drains through the reactor, losing activity en route. It arrives at the bottom in essentially spent condition and is discarded. Aluminum chloride carried overhead in the reactor products is returned to the reactor from the bottom of the recovery tower. The rest of the process is the same as in the vapor-phase processes. 

Emulsion polymerization is applicable only to monomers that are relatively insoluble in water, such as styrene. A coarse emulsion of monomer in aqueous surfactant is prepared with a water-soluble initiator, say, H202 in the solution. The surfactant concentration is above the CMC, so surfactant molecules are present as monomers, micelles, and emulsifiers at the oil-water interface. Even an insoluble liquid like styrene dissolves in water to some extent. Therefore the monomer is present in coarse emulsion drops, solubilized in micelles, and as dissolved molecules in water. A schematic illustration of the distribution of surfactant, monomer, and polymer in an emulsion polymerization process is shown in Figure 8.14. 

Homogeneous catalysis by transition metal complexes almost always involves processes in which product-catalyst separation and catalyst recycling are important issues. For years, researchers have worked to find effective ways to isolate metal-complex catalysts in phases separate from those containing the catalyst, usually by anchoring the metal complex to a solid surface. As summarized by Driessen-Holscher, it is now evident that the method that has met with most practical success in this direction involves the use of multiple liquid phases. For example, rhodium complexes with water-soluble sulfonated ligands are used to catalyze alkene hydroformyla-tion, and the aqueous-phase catalyst and the organic products are easily separated as insoluble liquid phases. 

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