Study On Synthesis Process And Crystallization Of Analgin

Crystallization is a key step affecting the quality and yield of analgin.The traditional 4-methylaminoantipyrine(MAA)is got by pyrazolone after a series of organic reactions generation,then MAA,formaldehyde solution and sodium hydrosulfite condensate in alcohol;finally analgin is got by crystallization.The rate of crystallization is lower.The improvement of analgin condensation reaction and crystallization was studied and MAA was synthesized in the paper.Firstly,according to actual experience and measuring results of MAA,MAA was synthesized by increasing chloroform extraction and filtration process on the basis of traditional craft.Through the contrast experiment,the results showed that Good MAA was got by the increase of chloroform extraction and filtration process.It provides better raw materials for condensation reaction.Then,analgin is easily soluble in water.The rate of analgin crystallization can be affected by the water in the condensation reaction system.So the condensation process was researched.The results showed that analgin crystallization rate can be greatly improved by paraformaldehyde instead of formaldehyde solution.MAA by chloroform extraction and filtering compared with traditional MAA,the quality of analgin was improved;The best condensation conditions:firstly paraformaldehyde is depolymerized at 80? and in 35min,then put other raw materials and reacted in pH=7.2,the reaction time for 100min;the optimum crystallization conditions is that crystallization rate can be greatly improvedby paraformaldehyde;thecrystallization temperature of 15-20?,the crystallization time of 5-6h;then it was quietly placed to the crystallization temperature.The purity of product and the yield of crystallization are both high.The innovation of this paper was according to getting better MAA by increasing chloroform extraction and filtration process.Crystallization rate got greatly improved by paraformaldehyde instead of formaldehyde solution for condensation reaction.The purity of product can conform to the state pharmacopoeia requirements.