Caprolactam, which is mainly produced via the Beckmann rearrangement reaction, is an important chemical material. The strict specifications of caprolactam products make the refining process of caprolactam extremely im...Caprolactam, which is mainly produced via the Beckmann rearrangement reaction, is an important chemical material. The strict specifications of caprolactam products make the refining process of caprolactam extremely important. According to the different rearrangement process, the refining process of caprolactam is also different. The main refining sequence of liquid phase rearrangement products includes extraction, ion exchange, hydrogenation, and distillation. The refining process of gas phase rearrangement products is conducted mainly through distillation, crystallization, and hydrogenation. In this paper, the research progress of caprolactam refining technology will be summarized according to different rearrangement reaction processes, which will provide a reference for the selection of appropriate caprolactam refining process.展开更多
The comparative process for preparing 9-oxime erythromycin A (EMAO) is investigated. EMAO was synthesized and compared by the reaction of erythromycin and hydroxylamine hydrochloride with various bases such as sodium...The comparative process for preparing 9-oxime erythromycin A (EMAO) is investigated. EMAO was synthesized and compared by the reaction of erythromycin and hydroxylamine hydrochloride with various bases such as sodium acetate, triethylamine, etc. A new synthetic method is established. The oximation is performed under dynamic buffer system; less degradation impurities are formed. The yield of EMAO reaches more than 95%, HPLC analysis shows that the purity of EMAO is more than 90%, and the E/Z isomeric ratio preponderates over 7∶1.展开更多
06001 The Exposure Standard. Lin Yunzhu,MaRunshan,. Guo Zhengqiang:1(4). 1980. pp.258--265.An exposure Standard apparatus developed in NIM ispresented, The exposure range of this apparatus isfrom 0.001 to 10 lux·...06001 The Exposure Standard. Lin Yunzhu,MaRunshan,. Guo Zhengqiang:1(4). 1980. pp.258--265.An exposure Standard apparatus developed in NIM ispresented, The exposure range of this apparatus isfrom 0.001 to 10 lux·second. and the uncertainty ofthe exposure is not exceed ±0.01 logarithmic unit. Itbasically satisfies the requirements of Sensitometry andCan be used to calibrate different types ofsensitometers.展开更多
文摘Caprolactam, which is mainly produced via the Beckmann rearrangement reaction, is an important chemical material. The strict specifications of caprolactam products make the refining process of caprolactam extremely important. According to the different rearrangement process, the refining process of caprolactam is also different. The main refining sequence of liquid phase rearrangement products includes extraction, ion exchange, hydrogenation, and distillation. The refining process of gas phase rearrangement products is conducted mainly through distillation, crystallization, and hydrogenation. In this paper, the research progress of caprolactam refining technology will be summarized according to different rearrangement reaction processes, which will provide a reference for the selection of appropriate caprolactam refining process.
文摘The comparative process for preparing 9-oxime erythromycin A (EMAO) is investigated. EMAO was synthesized and compared by the reaction of erythromycin and hydroxylamine hydrochloride with various bases such as sodium acetate, triethylamine, etc. A new synthetic method is established. The oximation is performed under dynamic buffer system; less degradation impurities are formed. The yield of EMAO reaches more than 95%, HPLC analysis shows that the purity of EMAO is more than 90%, and the E/Z isomeric ratio preponderates over 7∶1.
文摘06001 The Exposure Standard. Lin Yunzhu,MaRunshan,. Guo Zhengqiang:1(4). 1980. pp.258--265.An exposure Standard apparatus developed in NIM ispresented, The exposure range of this apparatus isfrom 0.001 to 10 lux·second. and the uncertainty ofthe exposure is not exceed ±0.01 logarithmic unit. Itbasically satisfies the requirements of Sensitometry andCan be used to calibrate different types ofsensitometers.
