Extractive distillation methyl ethyl ketone

To 5 parts of sodium acetylene in absolute ether 6 parts of dry methyl ethyl ketone was slowly dropwise added with ice cooling and stirring. Than the reaction mixture was poured into excess of acetic acid by ice cooling and extracted with ether. The ether extract was washed with solution of potash fo removing the diluted acetic acid and dried over potassium carbonate. The ether was distilled off and residual colorless oil methylpentynol had BP at 120°-121°C. Instead of sodium acetylene the solution of sodium acetylene in liquid ammonia may be successfully used. 

Preparation of Allyl 2,4-Dichlorophenyl Ether.48 A mixture of 10.8 g. (0.066 mole) of 2,4-dichlorophenol, 9.7 g. (0.080 mole 21.5% excess) of allyl bromide, 9.4 g. of powdered anhydrous potassium carbonate, and 50 cc. of methyl ethyl ketone is refluxed for four and one-half hours. After cooling, 100 cc. of water is added and the organic layer is separated. The aqueous layer is extracted twice with 50-cc. portions of petroleum ether (b.p. 90-100°) and the extracts are combined with the organic layer, which is then extracted twice with 50-cc. portions of 10% sodium hydroxide to remove any unreacted phenol and washed twice with water. After drying over calcium chloride, the solvent is evaporated and the residual oil is distilled under diminished pressure, giving 11.4 g. 85%) of colorless liquid, b.p. 98-99°/2 mm. dfl 1.258 1.5522. 

A solution of 12.5 g. (0.54 gram atom) of sodium in 125 g. of absolute ethanol (p. 142) is cooled and stirred while a mixture of 36 g. (0.50 mole) of methyl ethyl ketone and 73 g. (0.50 mole) of diethyl oxalate is added slowly. The reaction mixture is allowed to stand for 17 hours, after which it is cooled and acidified with dilute sulfuric acid. The mixture is extracted with ether the ether extracts are dried over sodium sulfate and distilled. All distillate boiling up to 100°/11 mm. is collected, and then the fraction boiling at 70-80°/0.6 mm. is collected separately. Redistillation of the latter fraction gives 50 g. of ester boiling at 75-78°/0.6 mm. 

The waxy raffinate from the solvent-extraction process is mixed with methyl ethyl, ketone, chilled, and filtered to remove the precipitated wax, after which the ketone is distilled away from the dewaxed oil. 

Another example presented by Hopkins and Fritsch17 consists of the use of azeotropic and extractive distillation to recover part of the methyl ethyl ketone... 

Acetone is used to extract fats, oils, waxes, and resins from natural products, to dewax lubricating oils, and to extract certain essential oils. The pharmaceutical industry uses acetone to extract B-vitamin complexes, alkaloids, antibiotics and enzymes. Methyl ethyl ketone is used to dewax lube oil. Methyl isobutyl ketone is used to dewax mineral oil, refine tall oil, and in extractive distillation and separation of isopropyl alcohol from ethyl and butyl alcohols. The extraction and purification of antibiotics and other pharmaceutical products utilize MIBK. Methyl isobutyl ketone is used in the extraction of rosin from pine wood and the extraction of heavy metal ion complexes from water solutions. 

These generalizations will always have exceptions. For example, acetic acid is extracted from water using methyl ethyl ketone, even though the equilibrium is unfavorable. In other words, the concentration of the acetic acid in water is higher at equilibrium than the concentration in the ketone. In this case, the extract of acetic acid and the ketone is much more easily separated by distillation than are extracts with alternative solvents. Methyl ethyl ketone is chosen in spite of its poor equilibrium. 

Lipopholic products are usually separated by extraction of the filtered broth, or the whole culture including the biomass, with water immiscible organic solvents, followed by separation of the solvent extracts and concentration in a vacuum evaporator. Chloroform, dichloromethane and ethyl acetate have been widely used as extraction solvents, however, 4-methyl-2-pentanone (methyl isobutyl ketone) appears to be the solvent of choice in the case of steroid substrates. Hydrophilic products, which cannot be extracted by organic solvents, can be isolated by ion exchange or by selective adsorption to polymeric resins (e.g., Amberlite XAD-resins). Resins of a wide range of polarity are available and lipophilic compounds can also be separated by this method. Final purification is accomplished in the usual way by crystallization, distillation or column chromatography. Preparative HPLC is a powerful tool for purification of small product quantities. 

Methyl-1,3-cyclohexanedione (126.1 g, 1.0 mol) and 300 mL distilled water are placed into a 1 liter round-bottomed flask fitted with a reflux condenser and a thermometer. Acetic acid (3.0 mL), hydroquinone (1.1 g) and methyl vinyl ketone (142 g, 167 mL, 2 mol, freshly distilled) are added and the resulting mixture is heated for 1 h at 75 °C. After cooling to room temperature, the reaction mixture is saturated with 103 g of sodium chloride and poured into 400 mL of ethyl acetate. After separation of the layers, the aqueous phase is twice extracted with ethyl acetate (150 mL each). The combined organic extracts are washed with two 200 mL portions of brine solution, dried over sodium sulfate, filtered, and then concentrated in vacuo to yield 210.8 g of 2-methyl-2-(3-oxobutyl)-1,3-cyclohexanedione as a pale yellow oil. 

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