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1.
利用变温^13C,^1H-NMR研究了过量配体存在下,氨三乙酸稀土络合物Ln(NTA)2(Ln=Ce,Pr和Nd)配体交换反应。在中必不溶液中,分子间的配体交换过程按中下机制进行:Ln(NTA)2^3-+HNTA^2-=Ln(NTA)(NTA)^3++NHTA^2-由溶液中溶液中自由NTA信号线宽分析了交换速率、确定了反应的活化能。结果表明,分子间配体交换反应化能与相应稀土络合物热力学稳定性有一定  相似文献   

2.
固体表面化学发光分析 Ⅱ.单矿物和钢中镍的微量测定   总被引:3,自引:0,他引:3  
本文建立了Ni(OH)^2-nn催化剂H2O2氧化Luminol的化学发光反应,与Ni^2+的催化化学发光反应比较,它更适合于固体表面化学发光分析。利用Ni^2+在用丙酮-盐酸-水作展开剂的纸上色谱行为中Rt值为零的特点,与大多数干扰离子进行分离,实现了单矿物和钢铁中镍的快速纸上色谱-固体表面化学发光分析。  相似文献   

3.
研究了在35±0.1℃、离子强度0.5mol/L(KCl)条件下,甲酸根、乙酸根、丙酸根和丁酸根分别催化Cu(Ⅱ)离子与四溴化间-四(N-乙酸甲酯基-3-吡啶基)卟啉(H2Tβ-N-ACMspyPBr4)的反应动力学及其机理,该类反应对卟啉和Cu(Ⅱ)离子均为一级反应,反应动力学方程为:d[CuP^4+]/dt=k{1.0+b[A^-])/(1.0+K3,4.[H^+]^2}[Cu^2+][P]T  相似文献   

4.
金属离子催化芳基吡啶甲酸酯水解动力学研究   总被引:2,自引:0,他引:2  
本文研究了25℃,离子强度I=0.1mol.dm^-3(KNO3)时,对硝基苯酚吡啶甲酸酯(PNPP)自发水解和金属离子Co(Ⅱ),Cu(Ⅱ),Ni(Ⅱ),Zn(Ⅱ),La(Ⅲ)的催化水解反应,探索了其反应的动力学及其机理。结果表明PNPP自发水解速率随着PH值的变化而发生显著的变化,这与PNPP结构中的吡啶氮原子的存在相关,而金属离子催化PNPP水解遵循下列方程:kobsd=Ka/「H^+」+kN(Kh「h^+」+K0+KohKw/H^+」)表明金属离子催化PNPP水解是通过外部OH对PNPP与金属离子形成的介稳配合物的亲核进攻,而不是由于M-OH进行的分子内的亲核反应,不同金属离子催化活性的大小与金属离子的电荷密度无关,可用配合物结构相对于底物中间态的稳定性得到解释。  相似文献   

5.
本文报道了5,10,15,20-四(4-乙酰氧基苯)卟吩(T(4AOP)P)及其Cu,Zn,Fe,Co,Ni配合物的合成及其在CH2Cl2-0.1mol/ITBAP体系中的循环伏安(CV)。研究结果。CV实验表明:Cu^2^+,Zn^2^=,Ni^2^+离子以稳定的+2价存在于T(4AOP)P中,电子转移反应在卟啉环上进行,而Fe^3^+,Co^2^+离子在氧化还原过程中发生价态变化。实验发现...  相似文献   

6.
多二茂铁基二氮杂己烷及其过渡金属配合物的合成   总被引:14,自引:1,他引:14  
乙二胺与二茂铁甲醛或双二茂铁甲基氟硼酸盐反应,合成了1,6-二(二茂铁基)-2,5-二氮杂己烷和1,1,6,6-四(二茂铁基)-2,5-二氮己烷,它们与过渡金属(Fe^2+,Co^2+,Ni^2+,Cu^2+,Zn^2+)盐在乙醇或乙醇-二氯甲烷中反应,是14种过渡金属配合物,对这些化合物进行了表征,二种配体及其铜配合物用作复合固体推进剂的燃速调节剂时,基本不迁移,而燃速催化效率均超过辛基二茂铁。  相似文献   

7.
Ni-B超细非晶合金的化学制备、反应机理及性质研究   总被引:10,自引:0,他引:10  
本文研究了水溶液中NiCl2与KBH4的反应及其产物Ni-B超细非晶合金的性质。详细探讨了反应的电化学基础和反应过程机理。发现Ni^2+与BH^-4的反应独立的基本反应组成,其中不可避免地存在BH^-4的分解即与H2O的反应,Ni-B则产生于Ni^2+的还原  相似文献   

8.
用PH电位滴定法测定 篱子(M^2+=Cu^2+,Co^2+,Ni^2=,Zn^2+,Cd^2+)与核酸碱基(P=腺嘌呤,胞嘧啶)形成的二夫配合物以及与腺甘-5'-三酸(ATP)形成的三元混配配合物的稳定常数,三元配合物相对于二元酚物的稳定性用平衡常数ΔlgKM大,这可能与三元混配配合物分子内存在配体间的芳环堆积、氢键作用以及πA-πB协同效应有关。  相似文献   

9.
系统地研究四异丙氧基酞菁的子化和脱质子化对吸收和发射光谱的影响,研究表明,三氟乙酸可对酞菁分子连续质子化,分别生成(H2Pc(O^iPr)4.H^+)^和(H2Pc(O^iPr)4.2H^+)^2+,而硫酸可使酞菁形成(H2Pc(O^iPr)4.4H^+^4+此外,NaOH/EtOH可使酞菁分子脱质子化生成(Pc(O^iPr)4)^2-反应一步完成,表明分子中的两个吡咯-NH-同步酸解,质子化可使  相似文献   

10.
Ni-Cu和MgO-SiO_2间的相互作用及其对催化性能的影响   总被引:2,自引:0,他引:2  
本文用TPR,IR,TPD和TPSR等技术研究了以表面改性法制备的MgO-SiO2(MSO)表面复合物担载的Ni-CU合金间的相互作用及其对CO加氢反应催化性能的影响.结果表明,NiO-CuO与MSO间的相互作用导致部分MO与MSO形成表面物种从而使金属组分氧化物还原温度明显升高;还原后的Ni-Cu/MSO表面上存在着两类活性中心,即合金相中的Ni与载体相中的Mg2+(或Mg2+-O);在两类活性中心的协同作用下,CO吸附除有孪生、线式和桥式吸附态物种外,还有一种新的卧式吸附态(Ni...C=O→Mg2+).这种吸附态的活化程度较高,易在表面上发生裂解形成Ni-C和Mg2+-O,其中Ni-C是加氢反应的碳源;H2在催化剂表面上发生解离吸附形成Ni-H和Mg2+-OH,前者比较活泼,是加氢反应的氢原.CO加氢生成烃类的反应在Ni中心上按"表面碳"机理进行,其生成CZH4的选择性高于80%;H2O的生成反应按2(Mg2+-OH)-→Mg2++(Mg2+-O)+H2O方式进行.  相似文献   

11.
The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.  相似文献   

12.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。  相似文献   

13.

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

  相似文献   

14.
Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.  相似文献   

15.
In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.  相似文献   

16.
Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, Mo, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

17.
翟宗玺  刘树深  夏树屏 《化学学报》1990,48(10):946-950
用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。  相似文献   

18.
The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.  相似文献   

19.
20.
设计了铁的锈蚀实验,说明了铁钉的处理方法,增加了温度、酸、碱的影响条件,实现了铁跟蒸馏水及空气中氧气快速反应而生锈,使实验在5 min左右就能够得到准确的结果。  相似文献   

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