The extraction training technology is mainly through practical operation, mastering the professional extraction technology and essentials. A method of separating and purifying a substance by transferring it from one solvent to another depending on the partition ratio (or different solubility) of the substance in two immiscible or sparingly soluble solvents.
Extraction is usually divided into liquid-liquid extraction and liquid-solid extraction.
For liquid-liquid extraction, there are two extractants. One type of extractant is usually an organic solvent, that is, the extraction principle is to transfer the substance from one solvent to another by using the difference in solubility (or partition coefficient) of the substance in two incompatible (slightly soluble) solvents. In order to achieve the purpose of extracting the substance, for example, the solubility of the organic compound in the organic solvent is generally greater than that in the water, and therefore, the organic solvent can be extracted from the aqueous solution by using an organic solvent which is incompatible or slightly soluble in water. .
According to the law of distribution, multiple extractions with a certain amount of solvent are more efficient than one extraction, and most of the material can be extracted by three extractions.
Another type of extractant is a reactive reagent whose extraction principle is to use it to chemically react with the extracted material. This extraction is often used to wash away small amounts of impurities or separate mixtures from the compound. Commonly used alkaline extractants such as sodium hydroxide, sodium carbonate (or sodium bicarbonate) can separate organic acids from the mixture or remove acidic impurities, while acidic extractants such as sodium sulfate and dilute hydrochloric acid can be separated from the mixture. The organic base or the removal of the basic impurities, the concentrated sulfuric acid can remove the unsaturated hydrocarbon from the saturated hydrocarbon, remove the alcohol and the ether from the alkyl halide.
For liquid-solid extraction, the extraction principle is to achieve the purpose of extraction and separation by utilizing the difference in solubility of the extracted material and impurities in the same liquid solvent in the solid sample.
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