| Oxytetracycline is a broad-spectrum antimicrobial drugs,can be used for the treatment of soft tissue infections and other diseases.The present technology of basic theory research is insufficient;at the same time the wastewater of oxytetracycline has the characteristics of high concentration of organic substance,high chroma,poor biodegradability and foaming easily,wherein the residual of oxytetracycline and oxalic acid with strong biological inhibitory,so difficult to deal with them.Because of the existing technology low level of resources,the high dilution of the fermentation broth,the serious waste of water resource,so that making the cost of processing very high.In this paper,the light of these problems will be research.(1)The solubility of oxytetracycline hydrochloride in acid alcohol solvent is an important basic theory data for the industrial production.The solubilities of oxytetracycline hydrochloride in short-chain alcohols,including methanol,ethanol,isopropyl alcohol and normal butanol,which were determined by equilibrium method in the temperature of 0-55?.The solubilities obtained were correlated with the mathematic model of empirical polynomial equation and the semiempirical equation.Using these two equations,the calculated solubilities are in great agreement with the experimental data,and the correlation results of polynomial equation are better than those of semiempirical equation,the empirical equation correlation coefficient>0.99.The test results shows that in methanol the solubility of oxytetracycline hydrochloride increased with the temperature rising,in ethanol and butanol the solubility decreases as the temperature increases,but in the isopropyl alcohol the solubility change with the temperature can not be fined.The results show that solubilties in short-chain alcohol with trace water and trace calcium are higher than those in pure short chain alcohol.At the same temperature the solubility of oxytetracycline hydrochloride in methanol and butanol are higher then in ethanol and isopropyl alcohol,so the methanol and butanol can be used as the extraction solvent of the oxytetracycline hydrochloride.(2)This paper studied using sodium carbonate instead of ammonia as alkali agent in crystallizing process of oxytetracycline,explores the influence of sodium carbonate concentrations and pH on the crystalline phase and the quality of product,and used the response surface optimization of the optimal concentration of the alkalizing agent and pH value.The results show that:when the sodium concentration of 16 g/100mL,pH 4.6,crystals are large and the product quality and the intermediate parameters are also very good.Plant scale test results showed that the sodium carbonate instead of ammonia as alkali agent is feasible,not only guarantees the quality of products,but also reduced the ammonia nitrogen in wastewater obviously.Get the pilot conditions as flow:the sodium carbonate concentration is 16 g/100mL,pH is 4.6,stirring speed 55 rpm/min,the alkalizing agent flow is 500 L/h.(3)The high unit decoloring solution crystallization process was studied.The first obtain the high unit decoloring from the high unit filtrate with 122type resin.Then respectively use ammonia and sodium carbonate as alkaline agent on the crystallization process,and used the response surface optimization of the optimal concentration of the sodium carbonate concentration and pH value.The results show that:with 14.5%ammonia as alkali agent,we can get the maximum crystals,the best quality of products and the potency of the mother liquor is not high when the pH is 4.6.Using sodium carbonate as alkaline agent the best crystallization process condition as flows:sodium carbonateconcentration is 12 g/100mL,pH value is 4.4. |
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