Study On The Technology Of Recovering 6-APA In The Mother Liquor Of 6-APA

As the parent nucleus of penicillin molecule,6-aminopenicillanic acid(6-APA)is an important intermediate for the production of a variety of semi-synthetic penicillin.With plenty use of semi-synthetic penicillin,the production of 6-APA is increasing.A large amount of mother liquor is generated in the process of producting 6-APA,which contains the 6-APA that have not be crystallized.45,000 tons of 6-APA mother liquor is produced in North China pharmaceutical factory annually,which contains 6-APA 180 tons.The recovery value calculated at 50% of the recovery can reach 16.47 million yuan.It shows that recycling 6-APA in the mother liquor has considerable economic benefits.If the mother liquor is let out directly,it will cause a waste of resources and can increase the processing load of the waste water,so recovering 6-APA in the mother liquor has important social benefits and economic benefits.On the basis of the literature review,a new method applied to recover the 6-APA in the mother liquor was put forward in this paper.The main process contained resin adsorption,nanofiltration,crystallization and purification.First,the method of resin adsorption was applied to remove the organic solvent in 6-APA mother liquor.The adsorption effect of five kinds of resin was tested and the D-V resin was selected and employed in this study.The loss rate of the process of resin adsorption has only 1.42%.Second,6-APA mother liquor was concentrated by nanofiltration and the concentration multiple is 10.Then,the concentrated liquor was crystallized using the method of isoelectric point.The measured value of the isoelectric point of 6-APA was 4.2,the color of crystallization was more yellow than the standard 6-APA,so the crystallized 6-APA was unqualified.In the end,the crystallized 6-APA was refined by the method of decoloring recrystallization,and the best decoloring conditions were explored.The qualified recrystallization product was obtained.The content of 6-APA was more than 99% and total yield of the single cycling was 62.37%.