Research On Synthesis Of Hydroxyalkylpiperazine By Aqueous Phase And Desulfurization Performance

Hydroxyalkylpiperazine is an important pharmaceutical intermediate and organic chemical raw material.However,alcoholic organic solvents are often used in the synthesis process of Hydroxyalkylpiperazine.The production process consumes a large amount of energy and has many steps,and the product and solvent may be lost during the separation process.In this paper,N,N'-bis?2-hydroxypropyl?piperazine?HPP?,N,N'-bis?2-hydroxyethyl?piperazine?BHEP?and N-?2-hydroxypropyl?piperazine?HPPZ?were directly prepared by using water as the reaction solvent to replace the alcoholic organic solvents such as methanol and ethanol used in the preparation of hydroxyalkyl piperazine organic amines,which has the characteristics of being clean,inexpensive,without a separation process,and can be directly formulated into an aqueous solution of a desulfurizing agent.In this paper,piperazine?PZ?and propylene oxide?PO?were used as raw materials to prepare N,N'-bis?2-hydroxypropyl?piperazine?HPP?organic amine aqueous solution directly using water as solvent.Through thermodynamic analysis,the thermodynamic parameters of the main reaction and possible side reactions during the reaction were calculated,which provided a basis for the study of HPP synthesis using water as solvent.The process conditions such as ratio of reaction raw materials and reaction temperature were optimized and the products were characterized by GC and GC-MS.The molar ratio of PZ to PO was 1 to 2.05,the reaction temperature was 5?,the reaction time was 12 h,and under the optimized conditions of slowly adding PO,the HPP content in the product was 96.77%.The product absorption and desorption of SO₂ properties were determined,the desiccant had a saturated absorption of sulfur dioxide of 0.7273mol/mol and a desorption rate of 98.29%,and the results indicate that the absorbent formulated directly from the product has good sulfur dioxide absorption capacity and can be reused by thermal desorption.Substrate expansion of the route,using piperazine?PZ?and ethylene oxide?EO?as raw materials,using water as solvent,one-step preparation of N,N'-bis?2-hydroxyethyl?piperazine?BHEP?An aqueous solution of an organic amine.Through thermodynamic analysis,it is calculated that the main reaction and possible side reactions are exothermic reactions during the reaction.The molar ratio of the raw materials PZ and EO,the reaction temperature and the reaction pressure were optimized and the products were characterized by GC and GC-MS.The molar ratio of PZ to EO is 1 to 2.05,the reaction temperature is 10?,the reaction time is 6 h,and the reaction pressure is-0.09 MPa.The content of BHEP in the product is 95.93%.It is shown that the saturated absorption of sulfur dioxide in the solution is 0.7476 mol/mol,and the desorption rate is 97.11%.N-?2-hydroxypropyl?piperazine?HPPZ?was synthesized by reacting PZ and PO with hydrogen ions as a nitrogen end group protecting agent.The effects of hydrogen source,raw material molar ratio and reaction temperature on the reaction were studied.The optimized reaction conditions were as follows:citric acid was used as the terminal protecting agent,the molar ratio of piperazine to citric acid was 1:0.37,piperazine and propylene oxide.The molar ratio is 1:1,and the content of HPPZ in the product reaches79.50%when the reaction temperature is 5?.The preparation method is green,the protection and deprotection process is simple,and has good economic benefits.