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1.
研究了在CH3OH,C2H5OH,H2O3种溶剂体系中^99mTcO4-,乙酰苯肼、还原剂与本体Et2NCS2Na的反应,以制备含  相似文献   

2.
合成了二苯乙二酮缩双苯胺锰的配合物,研究了其对CO2的固定及催化CO2同有机底物反应。反应产物经IR,^1H-^13C-NMR、NMR、元素分析等测定,结果表明:二苯乙二酮缩双苯胺锰是富电子配合物,可在温和条件下固定和催化转化CO2为有机酸。  相似文献   

3.
用AM1方法(采用UHF计算程序)研究了CH3C9O)OONO2,CH3C(CH2)C(O)OONO2和C6H5C(O)OONO2热消除NO2形成自由基的反应,计算的活化能分别为118.58,108.93和106.53kJ.mol^-1。  相似文献   

4.
用AM1方法研究了NO与C2H2热反应的机理。结果表明,生成CO与HCN和CH2O与HCN反应的速控步的活化能分别为200.593kJ.mol^-1和252.843kJ.mol^-1。  相似文献   

5.
(N(P(C6H5)3)2(HFe3(CO)11)与异氰酸苯酯反应,酸化后给出了簇合物Fe6(CO)14(μ-CO)3-(μ-η^2-OOCNC6H11)异氰酸苯酯的C=O双键劈开加氧,以(μ-η^2-OOCNC6H11)形式配位于2个铁原子,异氰酸苯酯的苯加氢还原子为环己烷,同时表征了产物的IR,^1HNMR和MS谱。  相似文献   

6.
用MNDO方法研究了ΘΟ-ΟⅡC-CH2Cl脱Cl^Θ的反应途径和过渡态,论证了O作为临基参预反应的可行性和优越性。  相似文献   

7.
在自组装的量热装置中,同步记录了KBrO3-CH2(COOH)21-H2SO4-Ce(NO3)3体系的热动和电位振荡曲线。实验结果表明,在[Ce^4+]/[Ce^3+]呈周期变化的同时,伴随吸热和放热过程交替进行。实验结果与按FKN机理理论分析一致,吸热效应主要与Br2O4离解为BrO2有关,放热效应则与丙二酸的溴代及溴代产物的氧化胶有关。本工作成功地将量热计用于动态热热信号检测,为研究振荡反应建  相似文献   

8.
在密闭循环反应器中,于290℃下研究了CO存在下催化剂MTPP-CeOx-SiO2(M=Co^2+,Ni^2+,Cu^2+)催化还原NO或N2O的反应。催化NO还原的活性顺序是NiTPP>CoTTP>CuTPP,而N2O还原和NO深度还原为N2的顺序是NiTPP>CuTPP>CoTPP.NOx还原的催化特性和MTPP的电化学氧化机理有关(取决于中心金属或卟啉环被氧化的次序)。CO不仅还原NOx而且  相似文献   

9.
报道了Ce(Ⅲ)在NH4NO3-C2H5OH-H2O体系中形成配合物的事实,测定其具体存在形式可表述为:(Ce(NO3)5C2H5OH)^2-。  相似文献   

10.
本文研究了在NMF-(C2H5)4NOH水溶液体系中C60修饰电极的电化学性质。以循环伏安法得到三对C60修饰电极的单电子氧化-还原峰,电极反应为半可逆反应,讨论了底液的组份、电位扫描范围与电极性能的关系,对C60修饰电极的电化学催化特性也做了初步的探讨。  相似文献   

11.
考察了无机氮源NH4 Cl和不同有机氮源对重组枯草芽孢杆菌 2 4 / pMX4 5核黄素发酵的影响 .实验结果表明 ,NH4 Cl作为基础氮源对菌体生长和核黄素合成均有抑制作用 .采用不同有机氮源进行核黄素发酵 ,以酵母粉为氮源时发酵单位最高 ,而蛋白胨为氮源时核黄素发酵单位最低 .  相似文献   

12.
To avoid unfavorable environmental condi- tions, Scrippsiella trochoidea is capable of forming a resting cyst in the process of growth. In the present study, we investigated the effects of nitrate and ammonium on the growth and encystment of S. trochoidea. We incubated S. trochoidea in modified f/2 media without nitrogen and silicate in flasks. The flasks were divided into two groups. Nitrate was added as a nitrogen source in the first group, and ammonium was added in the second group. The concentrations of the nitrogen compounds were 0, 10, 30, 60, and 90 μmol/L. The results indicate that NO3--N favors cell growth, and the cultures with a higher concentration of NO3--N were ineffective at forming cysts. In contrast, NH4+-N promoted cell growth and cyst formation. At similar concentrations as NO3--N, NH4+-N had a toxic effect on cell growth and increased the cyst formation ratio. Thus, the NH4+-N concentration is an important factor for controlling encystment. We believe that the impact of NH4+-N in inducing cyst formation may be a useful feedback mechanism in ecological systems.  相似文献   

13.
Dinitrogen fixation by a thermophilic methanogenic bacterium   总被引:4,自引:0,他引:4  
N Belay  R Sparling  L Daniels 《Nature》1984,312(5991):286-288
Methanogenic bacteria are known to use NH+4 as a nitrogen source for growth. Previous work with an impure methanogenic culture suggested that a methanogen might fix atmospheric dinitrogen as a nitrogen source, but no further work on this phenomenon has been documented. We have now examined the use of N2 by Methanococcus thermolithotrophicus and find that the organism can grow well, with multiple transfers, in medium having N2 as the source of nitrogen. Control cultures without N2 and containing less than 0.1 mM NH+4 do not grow. Growth yields with N2 are on the average one-third those with NH+4, suggesting that, as in other nitrogen-fixing organisms, this bacterium requires a large amount of ATP for the reduction to occur. After growing in NH+4-containing medium, a long lag is observed before growth begins with N2 as the nitrogen source; the NH+4 levels must be very low for growth to begin. Cells grown in N2-fixing conditions reduce acetylene to ethylene. The discovery of a nitrogen-fixing archaebacterium has important implications for studies on the evolution of nitrogenase, and the fact that M. thermolithotrophicus nitrogenase is active at 64 degrees C suggests that a novel enzyme is involved.  相似文献   

14.
针对福州市某水厂原传统处理工艺不能有效去除微污染水源水氨氮,出厂水氨氮不能稳定达标的情况,采用臭氧-生物活性炭(O3-BAC)处理工艺对水厂进行了中试研究,研究了臭氧投加量、水温、臭氧接触室气水比、活性炭滤池空床停留时间(EBCT)、流向等因素对氨氮去除的影响.结果表明:对于氨氮浓度为0.6~2.0 mg·L-1的微污染水源水质,最佳的臭氧投加量为2 mg·L-1;且当水温为16~24℃,臭氧接触室气水比为5∶3∶2,EBCT为15 min时,氨氮的去除效果在75%以上;此外,与下向流工艺相比,上向流工艺具有较高的去除率.  相似文献   

15.
L—苹果酸产生菌Aspergillus flavus HLD—12产酸条件的研究   总被引:3,自引:0,他引:3  
本文报道HLD-12菌株发酵L-苹果酸的特点.研究了碳源、氮源、温度、CaCO3、金属离子和促进剂等因素对HLD-12菌株苹果酸发酵的影响,确定了HLD-12菌株的最佳产酸条件,其中最适碳源为8%的葡萄糖,最适氮源为0.15%的(NH4)2SO4,CaCO3浓度为7%。生物素和丙氨酸在一定浓度范围内能显著提高HLD-12菌株的产酸水平。  相似文献   

16.
张冬艳  Yu  Fang  Bai  Fengwu  An  Lijia 《高技术通讯(英文版)》2006,12(4):446-448
The effects of initial sucrose concentration, nitrate to ammonium ratio, total N concentration and phosphate concentration in medium on cell growth and isocamptothecin A and B synthesis by suspension call culture of Camptotheca acuminata were investigated in 250 mL shake flasks. 30 g L^-1 sucrose concentration was beneficial to secondary metabolites synthesis. The cell growth and metabolites synthesis were also affected by the ratio of NO3^-/NH4^+ , and nitrate was tavourable for cell growth. The maximum dry weight was achieved when nitrate was used as the sole N souree. The effect of total initial N on the cell cultures was also investigated with NO3^-/NH4^+ ratio of 1 : 2. The final dry cell weight was similar throughout culture period and 50 mM initial N was favourable for secondary metabolite synthesis. 50 mM initial phosphate concentration facilitated both cell growth and secondary metabolites synthesis.  相似文献   

17.
以稻草秸秆原料,利用曲霉sp.HX-1固态发酵生产纤维素酶,研究了不同发酵时间、不同氮源和氮源浓度对曲霉sp.HX-1纤维素酶系的影响,并最终用硫酸铵分级沉淀和低温冷冻干燥的方法得到混合纤维素酶干品.结果表明,发酵6 d后稻草秸秆产生的纤维素酶活力单位最大,分别为CMC酶307 U/mL,C1酶841 U/mL、β-葡萄糖苷酶205 U/mL.以不同氮源优化发酵条件时发现,NH4NO3质量浓度为1 g/L时CMC酶活力达到1 652 U/mL,且失重率也到达最大值17.42%;NH4Cl质量浓度为0.5 g/L时,C1酶活力达到1 807 U/mL;尿素(UREA)质量浓度为2.0 g/L时,β-葡萄糖苷酶活力为2 033 U/mL,这表明氮源对曲霉sp.HX-1纤维素酶系的影响很大.最后在NH4NO3质量浓度为1.0 g/L的条件下,将120 g稻草秸秆发酵6 d,从发酵液中提取得到8.851 7 g混合纤维素酶的干品.此实验为以后探讨碳源或者其他因素的影响提供方法借鉴,也可以为获得纤维素酶混合酶干品的获得提供参考方法.  相似文献   

18.
黄蘑(Tricholom a gam bosum (Fr.) Gill)为内蒙古锡林郭勒草原的珍贵野生食用菌.通过对其菌丝体营养生理特性的初步研究,结果证实:1) 该菌在供试的C源中以麦芽汁利用最好;2) N 源的利用以(NH4 )2 HPO4 效果最佳,而且该菌种也能够利用有机态的N(即蛋白胨);3) 就供试的培养基来看,MMN 为最适培养基;4) 黄蘑菌丝体对pH 值的适应范围比较广,但更喜欢偏碱性的环境  相似文献   

19.
研究了无机与有机氮源对庆大霉素合成与分泌的影响。分别在初始培养基中及进入生物合成期的发酵液中添加硫酸铵、硝酸钠和各种氨基酸,初始培养基中添加硫酸铵浓度为0.1g/L时,总效价提高了23%,同时,硫酸铵对庆大霉素组分也有一定影响。在培养至24h添加8g/L硝酸钠,总效价提高55%,而在初始培养基中分泌率提高了33%,在生物合成期添加0.8g/L赖氨酸,总效价提高了64%,同时在静息细胞培养基中进行验证实验。  相似文献   

20.
从新疆油田油井旁土样富集、筛选得到一株高效石油烃降解菌HL-6,经初步鉴定为红球菌属(Rhodococcus sp.).研究表明,使用乙醇作为碳源制备液体种子液是可行的,之后采用单因素试验设计先后对菌株生长的培养基组分及生长条件进行了优化.结果表明,菌株HL-6的最适生长条件为:碳源(柴油)浓度为0.5%、氮源选择(NH4)2SO4浓度为8g/L、磷源为KH2PO4:Na2HPO4摩尔比为3:1、酵母粉浓度为0.03g/L、培养时间为3d、培养温度为20℃、pH=7.6、装液量为30mL、接种量为1.5%、摇床转速为150rpm.验证实验和预期一致,优化后降解率达到89.80%,比最初的78.50%提高了14.4%.  相似文献   

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