Method for recovering oxytetracycline from oxytetracycline hydrochloride waste liquid

Abstract

The invention relates to a method for recovering oxytetracycline from an oxytetracycline hydrochloride waste liquid. The method comprises the steps of: slowly neutralizing hydrogen chloride in a waste liquid of oxytetracycline hydrochloride preparation, carrying out pressure filtration, distilling the filtrate under reduced pressure to recover methanol, distilling a residual liquid, adding purified water, adjusting the acidity with hydrochloric acid, then adding diluted sulfuric acid or water-soluble sulfate and acid sulfate to remove calcium ions in the solution, then adding potassium ferrocyanide and zinc sulfate to remove iron and other impurities, carrying out plate-frame separation, adjusting the acidity of the filtrate to precipitate oxytetracycline crystals, centrifugally separating, and drying under reduced pressure in vacuum to obtain oxytetracycline. The method has the advantages that the recovered oxytetracycline has high yield and good quality, normal recovery of methanol is not influenced, the used materials are low in price and consumption, and the recovery cost is low; most of added materials are converted into solid waste residues, which are easy to treat; after oxytetracycline is recovered from the waste liquid, the total amount of pollutants in the waste liquid is reduced; the process is simple and the operation is convenient; and compared with the original production process, only a small amount of simple equipment is increased.

Description

technical field [0001] The invention belongs to the technical field of chemical preparation of compounds, in particular to a method for recovering oxytetracycline from oxytetracycline hydrochloride waste liquid. Background technique [0002] Oxytetracycline hydrochloride is a widely used broad-spectrum antibiotic drug. At present, the preparation method adopted by most production enterprises is: dissolving oxytetracycline in anhydrous methanol solution containing hydrogen chloride, the obtained solution is decolorized and filtered, an appropriate amount of hydrogen chloride methanol solution is added to the filtrate, frozen and crystallized, and centrifuged to obtain hydrochloric acid soil Dry the wet product of oxytetracycline to obtain oxytetracycline hydrochloride; neutralize the mother liquor after centrifugal separation of the wet product with calcium carbonate, then add oxytetracycline, dissolve, decolorize, and filter; add an appropriate amount of hydrogen chloride me...

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Problems solved by technology

[0003] Because the oxytetracycline dropped into during the reaction process contains crystal water and impurities, neutralizes the hydrogen chloride in the mother liquor and adds calcium carbonate to generate water, after the mother liquor is repeatedly fed and used for many times, the impurity and moisture content are too high and cannot be continued to use. It has become a waste liquid; but a large amount of oxytetracycline, calcium chloride and impurities thereof are dissolved in the waste liquid, and there is no suitable method to reclaim oxytetracycline from the waste liquid. The usual processing method is: stir in the waste liquid Add strong base to neutralize it, and recover the methanol in it by vacuum distillation. After the waste liquid is neutralized by strong base and vacuum distillation, the molecular structure of oxytetracycline has been destroyed, and it has become an impurity. The pollutant in the waste liquid It is not easy to deal with by conventional methods, and it takes a lot of money to treat the waste liquid containing high-concentration pollutants; that is to say, the raw material oxytetracycline is wasted, and the cost of environmental protection and pollution control is increased, which pollutes the environment

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