摘要
针对氨基硫脲生产过程中产生大量的高盐、高COD废水的问题,设计了排氨法生产氨基硫脲新工艺,将副产氨气排出反应体系,通过氨吸收塔制备氨水,代替液碱应用于制备2-氨基-1,3,4-噻二唑的中和工序,实现副产氨气高效回收、利用,盐酸使用量减少84%,废水中NH4Cl的含量减少86%,废水产生量减少63%,大幅度降低高盐、高COD废水的产生量,降低生产成本,实现清洁生产。通过投料比、排氨时间、回流时间、异构化剂丙酮加入量和反应母液循环利用等工艺条件的对比实验,获得制备氨基硫脲的最佳工艺条件:硫氰酸铵和水合肼摩尔比1∶0.7,排氨时间为4 h,回流反应时间为3 h,异构化剂丙酮加入量为7 kg,反应母液与水的加入质量比为2∶1。通过投料比、盐酸投料量、反应时间、中和反应所用碱的种类等工艺的优化研究,获得制备2-氨基-1,3,4-噻二唑的最佳工艺条件:n(氨基硫脲)∶n(甲酸)=1∶1.1,盐酸加入量为80 L,反应时间为5 h,用氨水或氨气代替氢氧化钠溶液调节反应液的pH。通过绿色制备工艺研究,实现氨基硫脲和2-氨基-1,3,4-噻二唑的收率和产品纯度的提升。
In view of the problem that a large number of high salt and high COD wastewater are produced in the production of thiosemicarbazone, a new process for the production of thiosemicarbazone by ammonia discharge method is designed.A large number of by-product ammonia gas produced in the preparation of thiosemicarbazone is discharged from the reaction system, ammonia water is prepared by ammonia absorption tower, and is applied to the neutralization process of the preparation of 2-amino-1,3,4-thiadiazole instead of sodium hydroxide solution, so as to realize the efficient recovery and utilization of by-product ammonia gas in the production process.Amount of hydrochloric acid used is reduced by 84%,the content of NH4Cl in wastewater is reduced by 86%,and the output of wastewater is reduced by 63%.The output of high salt and high COD wastewater is greatly reduced, the production cost is reduced, and cleaner production is achieved.The optimum process conditions for preparing thiosemicarbazone were obtained through the contrast experiments of feed ratio, ammonia removal time, reflux time, the amount of isomerizing agent acetone and the recycling of reaction mother liquor.The molar ratio of ammonium thiocyanate to hydrazine hydrate is 1∶0.7,the ammonia removal time is 4 h, the reflux reaction time is 3 h, the amount of isomerization agent acetone is 7 kg, and the proportion of reaction mother liquor to water is 2∶1.Through the optimization of the preparation process conditions such as the feed ratio, the amount of hydrochloric acid, the reaction time, and the type of alkali used in the neutralization reaction, the optimal process conditions for the preparation of 2-amino-1,3,4-thiadiazole were obtained.Thiosemicarbazone∶formic acid is 1∶1.1,the amount of hydrochloric acid added is 80 L,and the reaction time is 5 h.The pH of reaction solution was adjusted with ammonia water or ammonia gas instead of sodium hydroxide solution.Through green preparation process research, the yield and purity of thiosemicarbazone and 2-
作者
霍二福
程伟琴
冯明
王延花
刘晨义
王柏楠
朱冰
王宏力
HUO Er-fu;CHENG Wei-qin;FENG Ming;WANG Yan-hua;LIU Chen-yi;WANG Bo-nan;ZHU Bing;WANG Hong-li(Henan Chemical Industry Institute Co.,Ltd.,Zhengzhou 450052,China;Quality Inspection and Analytical Test Research Center,Henan Academy of Sciences,Zhengzhou 450008,China;Pingdingshan Mingyuan Chemical Co.,Ltd.,Pingdingshan 467002,China;Henan Technical Institute,Zhengzhou 450042,China)
出处
《应用化工》
CAS
CSCD
北大核心
2023年第1期138-142,151,共6页
Applied Chemical Industry
基金
河南省科技攻关项目(182102311010)
河南省科学院基本科研费项目(220608001,220608036)。
关键词
2-氨基-1
3
4-噻二唑
氨基硫脲
氨气回收利用
绿色制备工艺
工艺优化
2-amino-1
3
4-thiadiazole
thiosemicarbazide
recovery and utilization of ammonia
green preparation process
process optimization
