Ether-water azeotropes

D8. We have a feed of 15,000 kg/h of diisopropyl ether (C0 H 4 0) that contains 0.004 wt frac water. We want a diisopropyl ether product that contains 0.0004 wt frac water. Feed is a saturated liquid. Use the system shown in Figure 8-4. operating at 101.3 kPa. Use L/D = 1.5 (L/D) -Determine (L/D), L7D, optimum feed stage, and total number of stages required. Assume that CMO is valid. The following data for the diisopropyl ether— water azeotrope are given Trans. MChE, 36, 593,1940) y = 0.959, Separator Top layer x = 0.994 bottom layer x = 0.012 at 101.3 kPa and 62.2°C. All conpositions are weight fractions of diisopropyl ether. 

Freshly opened cans of anhydrous ether (Fisher) were used in the extraction process. Efficient drying over MgSC>4 (under nitrogen) is needed to avoid excessive loss of product in the forerun as a product/water azeotrope. The one-hole rubber septum used for ihe transfer process was obtained by using a cork bore of the appropriate size on a 24/40 rubber septum (Aldrich Chemical Company, Inc.). Rotary evaporation to remove the ether was carried out at 200-300 mbar (150-225 mm)... 

The complexes may also be prepared by the addition of a solution of carboxylic ligand to an equivalent amount of (i) a lanthanide carbonate [28], (ii) hydroxide [29] or (iii) oxide [30] with a slight excess of the latter. The insoluble part is filtered and the filtrate evaporated to obtain crystalline complex. Anhydrous lanthanide complexes of small chain carboxylic acids may be prepared by (i) the dissolution of lanthanide carbonate in excess of the carboxylic acid, followed by heating to obtain complete dissolution of the suspension and partial evaporation of the solution to obtain the crystals [31], (ii) anhydrous lanthanide is converted into the corresponding monochloroacetate by the addition of an excess of monochloroacetic acid, followed by heating under reflux at reduced pressure for 2 h. Then ether is added to precipitate the salt [32], (iii) the addition of dimethyl formamide and benzene to lanthanide acetates and distillation of the water azeotropes to obtain anhydrous complexes. The last procedure yielded lighter lanthanide complexes solvated with dimethyl formamide [33], The DMF may be removed by heating in a vacuum at 120°C. 

Properties Straw- to purple-colored liquid. D 0.88 (20C), 95% distills between 85 and 109C, wt/gal 7.33 lb, refr index (20C) 1.406. Insoluble in water water azeotrope at 77-82C approximately 90% CjHjjCI, miscible with alcohol and ether. Flash p 38F (3.3C) (OC). Components 1-chloropentane, bp 107.8C 2-chloropentane, bp 96.7C 3-chloropen-tane, bp 97.3C l-chloro-2-methylbutane, bp 99.9C l-chloro-3-methylbutane, bp 98.8C 3-chloro-2-methylbutane, bp 93.0C 2-chloro-2-methylbutane, bp 86.0C. 

Any higher alcohols that may have formed in the process from traces of higher olefins present in the propylene feed are absorbed from the azeotrope into mineral oil, in which isopropanol is insoluble. Pure isopropanol is obtained by ternary distillation of the cleaned water azeotrope with the appropriate proportion of added di-isopropyl ether. The ternary azeotrope (Table 19.2) is the top product from the column, and pure isopropanol is removed from the bottom (see Section 16.4 for related information). 

The bottom of this tower, a mixture of C4 and ether produced in the second stage, is recycled to the first column while the overhead stream (C4 and ethanol) is sent to the alcohol extraction tower. In this column, ethanol is removed by counter-current washing with alcohol-free water while C4 raffinate, isobutene-free, is sent to battery limits. The stream water/ethanol is finally sentto an additional fractionation tower where the ethanol-free water, recovered as bottom stream, is recycled to the washing tower, and the overhead ethanol/water azeotropic stream is recycled to the reaction stages. 

Examples of the separation of heterogeneous azeotropes using such a process include n-butanol-water, ethyl acetate-water, and ethyl ether-water (Othmer, 1963). 

Polymerization. Typically, the dihydric phenol (1 mole) and aqueous alkali metal hydroxide (2 moles) are mixed under an inert atmosphere in sulfolane and benzene. The water from the aqueous solution plus metal phenoxide formation is removed by distillation of a benzene-water azeotrope between 110° and 140°C. After water removal has been completed, the excess benzene is distilled off, the anhydrous salt in sulfolane cooled to 70°-80°C, and bis(4-chlorophenyl)-sulfone (I) added. The temperature is increased gradually to 200°C and held for four to five hours. Methyl chloride is bubbled in at the end of the polymerization to convert any terminal phenoxide groups to methyl ethers (10). 

For the preparation of terf-butyl ethyl ether,661 tert-butyl alcohol (1 mole) is added gradually to a boiling mixture of ethanol (2 moles) and twice that amount of 15 % sulfuric acid, and the azeotropic ether-water mixture is removed by continuous distillation. This gives a 95 % yield. 

Methyl-t-butyl ether (METH-el TER-she-air-ee BYOO-till EE-thur) is a volatile (evaporates easily), colorless, flammable liquid that forms an azeotropic mixture with water. Azeotropic mixtures are combinations of two or more liquids that boil at the same temperature and, therefore, cannot be easily separated from each other. 

Severe interference of nonkeys or intermediate keys may entirely preclude satisfactory temperature control without composition compensation. An excellent example has been described by Anderson and McMillan (13). Their column (Fig. 18.7) sepeirated water and heavy ether from a mixed alcohol stream, the top product consisting of a volatile water-ether azeotrope and a volatile ether-alcohol azeotrope. Wa-... 

Azeotropic alcohol/ether/ water/heavies column... 

Azeotropic alcohol/ether/ water/heavies column (same column as in 1550)... 

Ethanol [64-17-5] (ethyl alcohol) is available as an ethanol-water azeotrope and in anhydrous form. Both forms are supplied completely or partially denatured. Complete denaturation is effected by adding methyl ethyl ketone. Toluene, petroleum ether, and special gasolines are usually used for partial denaturation. 

The azeotrope formed by water and diethyl ether is single phase. Unlike ethanol and several other solvents which have single-phase water azeotropes, it is impracticable to form a low-boiling ternary azeotrope to remove water because the boiling point of diethyl ether is so low that the condensing of any such system would be very difficult. 

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