Slight miscibility

The theory of the process can best be illustrated by considering the operation, frequently carried out in the laboratory, of extracting an orgaiuc compound from its aqueous solution with an immiscible solvent. We are concerned here with the distribution law or partition law which, states that if to a system of two liquid layers, made up of two immiscible or slightly miscible components, is added a quantity of a third substance soluble in both layers, then the substance distributes itself between the two layers so that the ratio of the concentration in one solvent to the concentration in the second solvent remains constant at constant temperature. It is assumed that the molecular state of the substance is the same in both solvents. If and Cg are the concentrations in the layers A and B, then, at constant temperature ... 

Physical Properties. Furfural [98-01-1] (2-furancarboxaldehyde), when freshly distilled, is a colorless Hquid with a pungent, aromatic odor reminiscent of almonds. It darkens appreciably on exposure to air or on extended storage. Furfural is miscible with most of the common organic solvents, but only slightly miscible with saturated aHphatic hydrocarbons. Inorganic compounds, generally, are quite insoluble in furfural. 

Completely miscible (O), partially miscible ia the cubic phase ( )), and not at all or very slightly miscible (O). 

Liquid sulfur dioxide expands by ca 10% when warmed from 20 to 60°C under pressure. Pure liquid sulfur dioxide is a poor conductor of electricity, but high conductivity solutions of some salts in sulfur dioxide can be made (216). Liquid sulfur dioxide is only slightly miscible with water. The gas is soluble to the extent of 36 volumes pet volume of water at 20°C, but it is very soluble (several hundred volumes per volume of solvent) in a number of organic solvents, eg, acetone, other ketones, and formic acid. Sulfur dioxide is less soluble in nonpolar solvents (215,217,218). The use of sulfur dioxide as a solvent and reaction medium has been reviewed (216,219). 

Pure carbon disulfide is a clear, colorless Hquid with a deHcate etherHke odor. A faint yellow color slowly develops upon exposure to sunlight. Low-grade commercial carbon disulfide may display some color and may have a strong, foul odor because of sulfurous impurities. Carbon disulfide is slightly miscible with water, but it is a good solvent for many organic compounds. Thermodynamic constants (1), vapor pressure (1,2), spectral transmission (3,4), and other properties (1,2,5—7) of carbon disulfide have been deterrnined. Principal properties are Hsted in Table 1. 

TABLE 1. SOME COMMON IMMISCIBLE OR SLIGHTLY MISCIBLE... 

Colorless gas pungent suffocating odor gas density 2.927 g/L at 20°C heavier than air, vapor density 2.263 (air=l) condenses to a colorless liquid at -10°C density of liquid SO2 1.434 g/mL freezes at -72.7°C critical temperature 157.65°C critical pressure 77.78 atm critical volume 122 cc/g dielectric constant 17.27 at -16.5°C dissolves in water forming sulfurous acid, solubility 22.97 g and 11.58 g/lOOmL water at 0° and 20°C, respectively, under atmospheric pressure very soluble in acetone, methyl isobutyl ketone, acetic acid, and alcohol soluble in sulfuric acid liquid SO2 slightly miscible in water. 

Bismuth Arsenides.—When bismuth and arsenic are melted together there is no evidence of chemical combination. The two elements are only slightly miscible in the molten state 7 and separate completely on solidification if an open vessel is used, but according to Heike 8 they are perfectly miscible if melted in a sealed tube. Descamps 9 melted a mixture of bismuth and excess of arsenic under fused boric oxide, keeping the temperature as low as possible, and obtained a product of density 8-45 and approximate composition Bi3As4, but it is doubtful whether this was a definite compound. 

PS/S-MMA-60. At this value of copolymer composition, one observes further increases in compatibility, with PS-600 and PS-2100 compatible in all proportions and even PS-10,000 showing slight miscibility. It is worth emphasizing here that for PS M = 4000 and higher, the compatibility criterion is optical only and therefore is not unequivocal. 

Maltitol Syrup occurs as a clear, colorless, syrupy liquid. It is a water solution of a hydrogenated, partially hydrolyzed starch containing maltitol, sorbitol, and hydrogenated oligo-and polysaccharides. It is miscible with water and with glycerin, and slightly miscible with alcohol. 

A colourless syrupy basic liquid, which fumes and absorbs carbon dioxide on exposure to air. F.p. 9°. B.p. 178° to 180°. Miscible with water and ethanol slightly miscible with ether. 

Fig. 18. Very slightly miscible polymer pairs often yield an inward shift of their respective glass transition.

While such lyophobic interactions must be weaker in ethylene glycol solution than in water, they should be considerably stronger in ethylene glycol, which is still only slightly miscible with hydrocarbons, than in nonaqueous solvents such as ethanol or dioxane, which are completely miscible with hydrocarbons at 25°C (see Section IV,B,3). It is therefore... 

COnsolute. A liquid, added to a mixture of two slightly miscible liquids, which is soluble in each of these liquids. 

Properties Commercially a mixture of n-alkyl chlorides, with C12H25C1 dominant. A clear, water-white, oily liquid faint fatty odor. Crystallization point -19C, d 0.863 (15.5/15.5C), distillation range 112-160C (5 mm Hg), flash p 235F (112C). Completely miscible with most organic solvents slightly miscible with alcohol immiscible with water. Combustible. 

Properties Liquid. D 1.2606 at 30/4C, mp 27.4-27.8C, bp 285C, flash p 330F. Miscible with water, acetone, toluene (at 30C). Slightly miscible with octanes, olefins, naphthenes. 

Properties Colorless liquid. D 1.0518 (25/25C), bp 205-206.5C, crystallizing point -37C, flash p 205F (96C) (COC), refr index 1.4301 (25C), surface tension 30 dynes/cm (25C), viscosity 2.18 cP (25C), pH (anhydrous) 7.0 (pH of 10 solution in distilled water 4.2). Miscible with water and most organic solvents, resins, waxes, etc. slightly miscible with zein, beeswax, petrolatum immiscible with anhydrous glycerin, glue, casein, arabic gum, and soybean protein. Combustible. 

Typical nonbasic localizing B solvents are acetonitrile and ethyl acetate. Acetonitrile is only slightly miscible with hexane ethyl acetate has a high UV cutoff of 260 nm. 

Most of the derivatives shown in Figure 8 are solvent extractable at low pH, and thus one of the classical methods used for antibiotic purification becomes accessible to cephalosporin C. To be commercially feasible, solvents should be selective and only slightly miscible with water. Extraction efficiency should be sufficiently high that multiple extractions are not required, and ideally should be efficient at low ratios so as to effect a concentration of the desired component. Emulsions and insoluble solids are anathema to extraction. Using these criteria, extraction of most of the cephalosporin C derivatives at low pH are far from ideal since mostly non-selective solvents (such as n-butanol and ethyl acetate) usually work best several extractions seem to be required, and derivatized cephalosporin C broth upon acidification will frequently result in emulsion formation. However, some derivatives behave better than... 

The oxidized product is withdrawn continuously and cooled. Oxidized products may then be separated from the hydrocarbon, that has not been attacked, by washing countcrcurrently with aqueous methanol which is fed in at the top of a scrubbing tower. The oxidized products are selectively dissolved by the methanol solution which is heavier than and only slightly miscible with the hydrocarbon. A final washing of the hydrocarbon with water in the same way is used to remove any methanol taken up by the hydrocarbon and to assure as complete a removal of product as possible. The unoxidized hydrocarbon may then be recirculated and the products recovered by rectification of the methanol and water-wash solutions. 

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