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Solvents such as acetone and ethanol can be used as extraction solvents after being miscible with water

Extraction is a science, today I will share with you a few special extraction methods, which will definitely give you value for money.

(1) n-butanol: most small molecular alcohols are water-soluble, such as methanol, ethanol, isopropanol, n-propanol, etc. Most high molecular weight alcohols are not water-soluble, but lipophilic and can be dissolved in organic solvents. However, intermediate alcohol solvents such as n-butanol are a good organic extraction solvent. N-Butanol itself is not soluble in water, and at the same time has the common characteristics of small molecular alcohol and large molecular alcohol. It can dissolve some polar compounds that can be dissolved with small molecular alcohols, but at the same time it is insoluble in water. Taking advantage of this property, n-butanol can be used to extract polar reaction products from aqueous solutions. Butanone: The nature is between small molecular ketones and large molecular ketones. Unlike acetone, which is soluble in water, butanone is insoluble in water and can be used to extract products from water.

(2) Butyl acetate: The nature is between small and macromolecular esters, and its solubility in water is very small. Unlike ethyl acetate, which has a certain solubility in water, it can extract organic compounds, especially amino acid compounds from water. Therefore, it is often used in the antibiotic industry to extract cephalosporins, penicillins and other macromolecular compounds containing amino acids.

Isopropyl ether and tert-butyl tert-butyl ether: The nature is between small molecule and macromolecular ether. The polarity of the two is relatively small, similar to n-hexane and petroleum ether, and their solubility in water is small. It can be used as a crystallization solvent and extraction solvent for molecules with very small polarity. It can also be used as a solvent for crystallization and extraction of more polar compounds.

(3) After the reaction is completed, the extraction method should be used first, and a part of the impurities should be removed first, which is the use of the different solubility of impurities and products in different solvents.

(4) The aqueous solution of dilute acid washes away a part of alkaline impurities. For example, if the reactant is alkaline and the product is neutral, the alkaline reactant can be washed away with dilute acid. For example, the acylation reaction of amino compounds.

(5) The aqueous solution of dilute alkali washes away a part of acidic impurities. The reactant is acidic, and the product is neutral, and the acidic reactant can be washed away with dilute alkali. For example, the esterification reaction of carboxyl compounds.

(6) Wash away a part of water-soluble impurities with water. For example, in the esterification reaction of lower alcohols, the water-soluble reactant alcohol can be washed away with water.

(7) If the product is to be crystallized from water and the solubility in the aqueous solution is greater, try adding inorganic salts such as sodium chloride and ammonium chloride to reduce the solubility of the product in the aqueous solution-salting out method.

(8) Sometimes two immiscible organic solvents can be used as the extractant. For example, the reaction is carried out in chloroform. Petroleum ether or n-hexane can be used as the extractant to remove some of the impurities with small polarity. Conversely, chloroform extraction can be used to remove the polarity. Big impurities.

(9) Two miscible solvents are sometimes incompatible with the addition of another substance. For example, in the case of water as the solvent, after the reaction is completed, the inorganic salts sodium chloride and potassium chloride can be added to the system. Saturate the water, add acetone, ethanol, acetonitrile and other solvents to extract the product from the water.

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