研究了N902/煤油从氨/氯化铵水溶液中萃取铜.考察了萃取时间、水相pH值、萃取剂浓度、温度等对萃取率的影响,以及酸度和时间对铜的反萃率的影响.实验发现,在研究的条件下萃取5 m in达到平衡,而反萃则需要15 m in达到平衡.萃取过程是吸...研究了N902/煤油从氨/氯化铵水溶液中萃取铜.考察了萃取时间、水相pH值、萃取剂浓度、温度等对萃取率的影响,以及酸度和时间对铜的反萃率的影响.实验发现,在研究的条件下萃取5 m in达到平衡,而反萃则需要15 m in达到平衡.萃取过程是吸热过程,测得△H=4.0 kJ/mol.在实验范围内,萃取率先随pH值增大而增加,当pH值超过10.2后,随着pH值增大反而降低.展开更多
The kinetics of extraction and stripping of copper （Ⅱ） was investigated by the single drop technique with a new extractant N902 （a derivative of the salicylal-doxime） and the rate equations of extraction and stri...The kinetics of extraction and stripping of copper （Ⅱ） was investigated by the single drop technique with a new extractant N902 （a derivative of the salicylal-doxime） and the rate equations of extraction and stripping were derived, respectively. The apparent activation energies of extraction and stripping were estimated to be 20.14 kJ/mol and 30.0 k J/mol.展开更多
In the present study, we introduced point mutations into Ac_rap A which encodes a polyketide synthase responsible for rapamycin biosynthesis in Actinoplanes sp. N902-109, in order to construct a mutant with an inactiv...In the present study, we introduced point mutations into Ac_rap A which encodes a polyketide synthase responsible for rapamycin biosynthesis in Actinoplanes sp. N902-109, in order to construct a mutant with an inactivated enoylreductase(ER) domain, which was able to synthesize a new rapamycin analog. Based on the homologous recombination induced by double-strand breaks in chromosome mediated by endonuclease I-SceI, the site-directed mutation in the first ER domain of Ac_rapA was introduced using non-replicating plasmid pL YERIA combined with an I-SceI expression plasmid. Three amino acid residues of the active center, Ala-Gly-Gly, were converted to Ala-Ser-Pro. The broth of the mutant strain SIPI-027 was analyzed by HPLC and a new peak with the similar UV spectrum to that of rapamycin was found. The sample of the new peak was prepared by solvent extraction, column chromatography, and crystallization methods. The structure of new compound, named as SIPI-rapxin, was elucidated by determining and analyzing its MS and NMR spectra and its biological activity was assessed using mixed lymphocyte reaction(MLR). An ER domain–deficient mutant of Actinoplanes sp. N902-109, named as SIPI-027, was constructed, which produced a novel rapamycin analog SIPI-rapxin and its structure was elucidated to be 35, 36-didehydro-27-O-demethylrapamycin. The biological activity of SIPI-rapxin was better than that of rapamycin. In conclusion, inactivation of the first ER domain of rap A, one of the modular polyketide synthase responsible for macro-lactone synthesis of rapamycin, gave rise to a mutant capable of producing a novel rapamycin analog, 35, 36-didehydro-27-O-demethylrapamycin, demonstrating that the enoylreductase domain was responsible for the reduction of the double bond between C-35 and C-36 during rapamycin synthesis.展开更多
An efficient and reliable approach based on solvent extraction to selectively recover copper from leaching solution of Jinchuan copper smelting ash has been developed in this work.And the extraction isotherm of 50%((?...An efficient and reliable approach based on solvent extraction to selectively recover copper from leaching solution of Jinchuan copper smelting ash has been developed in this work.And the extraction isotherm of 50%((?)) N902 with initial aqueous acidity of 19.6 g/L was determined at 25℃.The results show that the extractant,N902,has good selectivity to copper, and its saturated capacity of copper under the given conditions is over 23 g/L.The recovery rate of copper in the extraction is over 99%.And copper extraction equilibrium is reached in 90 s using 50% N902 with kerosene as the diluenting agent at an organic and aqueous volume phase ratio(O/A)of 1.Furthermore,over 99.5% of the loaded copper in the organic phase could be stripped by applying 196 g/L H_2SO_4 as the stripping agent.展开更多
文摘研究了N902/煤油从氨/氯化铵水溶液中萃取铜.考察了萃取时间、水相pH值、萃取剂浓度、温度等对萃取率的影响,以及酸度和时间对铜的反萃率的影响.实验发现,在研究的条件下萃取5 m in达到平衡,而反萃则需要15 m in达到平衡.萃取过程是吸热过程,测得△H=4.0 kJ/mol.在实验范围内,萃取率先随pH值增大而增加,当pH值超过10.2后,随着pH值增大反而降低.
基金Project supported by the Shanghai Leading Academic Discipline Project(Grant No.S30109)the Opening Project of Key Laboratory of Solid Waste Treatment and Resource Recycle(SWUST)+1 种基金the Ministry of Education(Grant No.09zxgk02)the Science and Technology Commission of Shanghai Municipality(Grant No.09DZ1204403)
文摘The kinetics of extraction and stripping of copper （Ⅱ） was investigated by the single drop technique with a new extractant N902 （a derivative of the salicylal-doxime） and the rate equations of extraction and stripping were derived, respectively. The apparent activation energies of extraction and stripping were estimated to be 20.14 kJ/mol and 30.0 k J/mol.
基金supported by the National Major Scientific Instruments and Equipment Development Projects(No.2011YQ15007208)Shanghai Science and Technology Support Project(No.12431901102)
文摘In the present study, we introduced point mutations into Ac_rap A which encodes a polyketide synthase responsible for rapamycin biosynthesis in Actinoplanes sp. N902-109, in order to construct a mutant with an inactivated enoylreductase(ER) domain, which was able to synthesize a new rapamycin analog. Based on the homologous recombination induced by double-strand breaks in chromosome mediated by endonuclease I-SceI, the site-directed mutation in the first ER domain of Ac_rapA was introduced using non-replicating plasmid pL YERIA combined with an I-SceI expression plasmid. Three amino acid residues of the active center, Ala-Gly-Gly, were converted to Ala-Ser-Pro. The broth of the mutant strain SIPI-027 was analyzed by HPLC and a new peak with the similar UV spectrum to that of rapamycin was found. The sample of the new peak was prepared by solvent extraction, column chromatography, and crystallization methods. The structure of new compound, named as SIPI-rapxin, was elucidated by determining and analyzing its MS and NMR spectra and its biological activity was assessed using mixed lymphocyte reaction(MLR). An ER domain–deficient mutant of Actinoplanes sp. N902-109, named as SIPI-027, was constructed, which produced a novel rapamycin analog SIPI-rapxin and its structure was elucidated to be 35, 36-didehydro-27-O-demethylrapamycin. The biological activity of SIPI-rapxin was better than that of rapamycin. In conclusion, inactivation of the first ER domain of rap A, one of the modular polyketide synthase responsible for macro-lactone synthesis of rapamycin, gave rise to a mutant capable of producing a novel rapamycin analog, 35, 36-didehydro-27-O-demethylrapamycin, demonstrating that the enoylreductase domain was responsible for the reduction of the double bond between C-35 and C-36 during rapamycin synthesis.
文摘An efficient and reliable approach based on solvent extraction to selectively recover copper from leaching solution of Jinchuan copper smelting ash has been developed in this work.And the extraction isotherm of 50%((?)) N902 with initial aqueous acidity of 19.6 g/L was determined at 25℃.The results show that the extractant,N902,has good selectivity to copper, and its saturated capacity of copper under the given conditions is over 23 g/L.The recovery rate of copper in the extraction is over 99%.And copper extraction equilibrium is reached in 90 s using 50% N902 with kerosene as the diluenting agent at an organic and aqueous volume phase ratio(O/A)of 1.Furthermore,over 99.5% of the loaded copper in the organic phase could be stripped by applying 196 g/L H_2SO_4 as the stripping agent.
