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1.
李全民  张丽敏 《分析化学》1999,27(10):1208-1210
研究了丙醇-溴化十六烷基三甲胺9CTMAB)-(NH4)2SO4-水体系萃取分离泵的行为及与常见离子分离条件。试验表明:调节pH1.0或3.0,能使Hg从Fe^3+,Co^2+,Ni^2+m,Zn^2+,Mn^2+,Cu^2+,Al63+等离子混合液中分离出来。  相似文献   

2.
氯化钠-二乙基二硫代氨基甲酸钠-丙醇体系萃取分离铜   总被引:7,自引:2,他引:5  
研究了氯化钠-二乙基二硫代氨基中甲酸钠-丙醇体系萃取铜的行为及丙醇水溶液分相条件的选择。实验表明,丙醇作为萃取溶剂,能萃取中性螯合物。在EDTA存在下,调节pH5-pH10,该体系能使Cu62+从常见元素Fe^3+,Co^2+,Ni^2+,Al^3+等离子的混合液中分离出来。  相似文献   

3.
氯化钾介质中铈(Ⅲ)的荧光特性及应用研究   总被引:4,自引:0,他引:4  
Ce^3+在pH〈6.2的KCl介质中受252.4nm的紫外光激发时,发射出的353.8nm荧光可用于痕量铈的测定。在pH5~6时,用Al2(SO4)3可消除Fe^3+的干扰。在0~3.0×10^-6mol/L范围内,荧光强度与Ce^3+的浓度遵守△F=2.37×10^6C-0.001方程(n-10,r=0.9999),检测限为6.0×10^-9mol/L。用于GWB07103(GSR-1)岩石…  相似文献   

4.
裉色光度法测定SO^2—3的研究   总被引:4,自引:0,他引:4  
本文研究了SO^2-3褪色碱蓝6B的反应,在pH5.2Ac-NaAc缓冲介质中,SO^2-3浓度在0.39-12mg/L范围内符合比尔定律,仅Fe^3+,Ni^2+,Cr^3+干扰测定,用于食品中SO^2-3的测定,结果令人满意。  相似文献   

5.
催化褪色光度法测定痕量钡   总被引:2,自引:0,他引:2  
刘佳铭  马同森 《分析化学》1999,27(10):1215-1218
Ba^2+能在pH5弱酸性介质中催化十二烷基苯磺酸钠(DBS)对铬黑T(EBT0的褪色反应。详细研究了动力学条件,确立测定钡的最适宜催化动力学条件。表观摩尔吸光系数ε620=3.0×10^-6L.mol^-1cm^-1,校正曲线方程为logA0/A=0.006260+0.08704CBa^2+(μg/L);线性范围0-16μg/L(r=0.9991);  相似文献   

6.
研究了二(2,4,4-三甲基戊基)膦酸的正辛烷溶液从盐酸介质中萃取钍的机理。在未控制离子强度下,萃取平衡反应为:Th^4++Cl^-+3(HA)2(o)→ThClA3(HA)3(o)+3H^+。在控制离子强度为1.0mol/L时,萃取反应为Th^4++2Cl^-+3(HA)2(O)→ThCl2A2.(HA)4(P)+2H^+。用饮和法确定的萃合物组成为ThClA3.计算了萃取反应的平衡常数及热力学  相似文献   

7.
2—氨基苯并噻唑萃取铑及铑,铱分离的研究   总被引:4,自引:0,他引:4  
本文研究用2-氨基苯并噻唑(简写ABT)溶剂萃取铑的最佳条件,在KI存在下于pH1~3,加热60min,所形成的络合物能定量地被己烷萃取,贱金属离子如Fe^3+,Al^3+,Cu^2+,Cd^2+,Co^2+,Ni^2+,Zn^2+,Mn^2+,Ca^2+,Mg^2+及铂族离子Pt(Ⅳ),Ir(Ⅳ)不被萃取,Pd^2+,可在未加入KI之前预先萃取分离,斜率测得萃合物组成为RhI3(ABT),红外光  相似文献   

8.
催化光度返滴定法测定微量锰的研究   总被引:1,自引:0,他引:1  
本文研究了催化光度反滴定法测定微量锰的原理,找到最佳实验条件,确立了实验方法,测定波长622nm;反应时间1min40s;活化剂NTA用量0.60mL,KIO4与孔雀石绿用量比为1.00:0.35,室温下滴定;用pH=5.4的乙酸-乙酸钠缓冲溶液控制溶液酸度;测定Mn^2+的浓度范围为1×10^-7~1×10^-5mol/L,Co^2+,Bi^3+,Ca^2+,Al^3+,Pb^2+,Cu^2+,  相似文献   

9.
罗瑾  吴玲玲 《电化学》1996,2(1):61-65
本文研究溶液pH值,配体及某些重金属离子对细胞色素C电化学活性的影响。实验发现:在pH=2.0和pH=10.0的磷酸盐缓冲溶液中,细胞色素C失活,用强的配体CN^-与铁卟啉发生配位取代反应虽使溶液相中的细胞色素C失活,但不影响吸附态的细胞色素C的活性;重金属离子Hg^2+,Cd^2+,Pb^2+对细胞色素C电化学活性影响的程度不同,影响大小的顺序为Hg^2+〉Cd^2+〉Pb^2+并对可能的机理进  相似文献   

10.
铽—钆—均苯四甲酸体系的共发光效应及其分析应用   总被引:9,自引:0,他引:9  
马文元  杨景和 《分析化学》1995,23(2):183-186
本提出了以均苯四甲酸为配体的铽的荧光测定法,试验表明:在pH=6.0-9.0的缓冲溶液中,钆离子能明显增强Tb^3+-均苯四甲酸二元体系的荧光强度。该体系已用于痕量铽的测定,其检出限为4×10^-9mol/L。  相似文献   

11.
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   

12.
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   

13.
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   

14.
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   

15.
Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.  相似文献   

16.
Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.  相似文献   

17.
The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe2O3. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

18.
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   

19.

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.

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20.
潘素娟  全灿  周俊波 《化学通报》2014,77(12):1165-1170
测量不确定度是表征合理地赋予被测量之值的分散性的参数。本文针对化学计量不确定度评定基础模型仅适用于线性模型、概率分布为正态分布或缩放位移t分布等局限,介绍了近年来不确定度评定的研究热点:蒙特卡罗方法(Monte Carlo Method,MCM),不确定度评定的来源、评定概念、评估方法及其发展过程,扩大了测量不确定度评定与表示的适用范围。  相似文献   

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