The Study On The Synthesis Of The Important Intermediate Of Cephalosporins

Because of its good therapeutic effect and huge application market,it has broaden prospects for Cefixime,so does the intermediates.The enzymatic hydrolysis method,which has been used by some foreign companies,is regarded as a eco-friendly process due to simple process,specificity,high-field,good quality and small environment pollution.This article used SBA-15 zeolite as supporter to synthetize immobilized penicillin acylase.And the article also did a research about catalytic cracking processes catalyzed by immobilized penicillin acylase to produce 7-AVCA and 7-ADCA.(1)Self-made big hole SBA-15 zeolite as supporters was used as supporter.Physical adsorption,chemical crosslinking and microwave assisted chemical crosslinking were used as immobilization methods.The addition of PEG400 was effective in increasing the activity,but it had little influence in microwave assisted method.With 15% PEG,chemical crosslinking method,6 h for immobilization,pH value as 7.5-8.0 and a 30-35 ? temperature,the activity of immobilized penicillin acylase would be about 800U/g.And the load capacity of this kind of immobilized penicillin acylase equals to 44 mg/g supporter.(2)Using self-made IPA to catalyze the cracking process of GLCE to produce 7-AVCA,a 98.64-99.34 % purity product would be produced.When the amount of enzyme equals to 140 U/g substrates,the concentration of substrates equals to about 4%,the pH value equals to about 7.5-8.0 and the temperature equals to about 28-30 ?,a 80% field and over 98% purity product would be synthetized.(3)Using self-made IPA to catalyze the cracking process of cephalosporin G acid to produce 7-ADCA,a 91.2% field and over 98% purity product would be synthetized when the amount of enzyme equals to 70 U/g substrates,the concentration of substrates equals to about 6%,the pH value equals to about 7.8-8.2 and the temperature equals to about 28-32 ?.