一步法合成乙二醇的工艺研究

以二叔丁基过氧化物(DTBP)为引发剂,以甲醇和甲醛为原料,采用一步法合成了乙二醇。考察了引发剂用量、反应温度、反应时间、甲醇与甲醛的质量比对一步法合成乙二醇的影响。确定一步法合成乙二醇的最优工艺条件为:反应温度200℃、反应时间4 h、甲醇与甲醛的质量比2∶1、引发剂用量(以原料总质量计)3%,主要产物为乙二醇和二乙二醇,其中乙二醇含量达到6.51%。

磷酸铵回流萃取工艺的研究

使用溶剂回流萃取法净化湿法磷酸,改进传统湿法磷酸与溶剂萃取的方法,利用磷酸铵在萃取剂中溶解度低的特点,制取磷酸铵,以达到清洁、高效、低能耗生产的目的。实验考察了反应温度、萃取剂、相比(油相与水相的体积比)等因素对磷酸铵收率及纯度的影响。较佳的工艺条件:正丁醇为萃取剂,萃取的相比为2,反萃相比为2.8,洗涤净化相比为0.5,在此条件下磷酸铵最终收率≥89%,磷酸铵固体中杂质钙离子和氯离子的质量分数分别≤10%和≤6.5%。实验结果表明,溶剂回流萃取法较传统的磷酸铵生产工艺生产流程简单,耗能小,且副产物少,环境污染小,但各方面研究还仍处于实验室研究阶段。

Nitrosation Reaction Without Nitrogen Oxide Waste Gas Emission and Its Engineering Practice

The gas-liquid phase equilibrium is used in controlling the nitrosation reaction process. Decomposition of nitrous acid and oxidation side reaction are suppressed in a closed reaction system. The system pressure is used as the criterion of the end of reaction, avoiding excessive feeding and reducing the decomposition of nitrous acid. The head space of the reactor is used as the gas buffer, stabilizing the feeding fluctuations and inhibiting the side reaction, decomposition of nitrous acid. Nitrogen oxide concentration is controlled at the minimum level. Thus the zero release of nitrogen oxide waste gas can be achieved without using any absorption process.