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1.
在pH4.0的介质中,Mo与新试剂4-(5-溴-2-噻唑偶氮0邻苯二酚和二苯胍反应形成稳定的三元离子缔合物其组成比Mo:5-Br-TAPC:DPG为1:3:2。该三元缔合物氯仿萃取液的λmax为536nm,对比度为119nm,表观ε为6.33×10^4L.mol^-1.cm^-1。钼含量在0-0.800,g/L范围内遵从比耳定律,并探讨了离子缔合物的结构。  相似文献   

2.
探讨题试剂与锌离子的显色反应条件,当PH为5.5,在TritonX-100存在下,DMTAQ与锌离形成红色配合物,最大吸收峰位于545nm,表观摩尔吸系数9.4×10^4L.mon^-1.cm^-1,锌量在0-25μg/50mL范围内符合比尔定律。该法可用于测定人发中的微量锌。  相似文献   

3.
反相离子对色谱法测定硫代硫酸根和碘离子的研究   总被引:4,自引:0,他引:4  
张晓彤  云自厚 《色谱》1997,15(1):57-59
首次利用S2O2-3和I-与Hg-EDTA二元络合物通过柱前衍生形成EDTA-Hg-S2O3和EDTA-Hg-I两种三元络合物的方法,实现了对S2O2-3和I-的间接反相离子对色谱分离和紫外检测。在ZorbaxODS柱上,用甲醇∶水=23∶77作流动相,内含对离子TBA+3.0mmol/L,EDTA1.0mmol/L,NaNO32.0mmol/L和缓冲剂KH2PO4-Na2HPO4(pH7.0),紫外254nm检测。S2O2-3和I-的最小检出限分别为61.1ng和37.6ng。方法简便,选择性好。  相似文献   

4.
Li^+忘记尖晶石构造LiAlMnO4的合成及离子交换性能   总被引:5,自引:0,他引:5  
用共沉淀/热结晶法制备了尖晶石型金属复合物LiAlMNO4用X-射线衍射、DTA-TG分析、FT-IR光谱/PH滴定和Kd测定研究了该化合物的Li^+抽出,嵌入及离子交换性质。研究表明,Li^+的抽出/嵌入过程主要是离子交换,为局部规整反应;该化合物酸处理产物对Li^+的交换容量约4.5mol/g,对Li^+显著了忘记性离子筛效庆。  相似文献   

5.
本文在pH5.5的乙酸-乙酸钠介质中,对以5-Br-PADAP作指示络合滴定法连续测定锌和铜进行了研究,对滴定的pH值及指示剂用进行了选择,试验了锌,铜不同配比的滴定结果,研究了共存离子的干扰。实验表明,用5-Br-PADAP作指示剂,EDTA作滴定剂连续和铜,滴定点颜色变化敏锐,准确度高,锌和铜均在0-20mg范围内与EDTA用量成正比,锌,铜比例在1:10-10:1范围内相互无影响。方法用于标  相似文献   

6.
何家俊  任英 《分析化学》1993,21(10):1122-1125
本文研究了铽(Tb)、钇(Y)、钆(Gd)及它们的混合物对铕(Eu)-噻吩甲酰三氟丙酮(TTA)-氯化甲基三烷基铵(N263)-Triton X-100体系的共发光效应,发现稀土离子混合物的共发光效应具有线性加和性,用混合共发光体系不仅能保持单个稀土离子的共发光体系的增敏性,并经过实际樯品分析的验证,结果令人满意。  相似文献   

7.
张光  张林林 《分析化学》1994,22(11):1155-1157
本研究了2-(6-硝基-2-苯并噻唑偶氮)-5-二甲氨基苯甲酸(6-NO2-BTAMB)与铜的显色反应。结果表明,在pH2.0 ̄4.5的乙醇水溶液中6-NO2-BTAMB与铜形成一种稳定的蓝绿色络合物,其最大吸收波长位于650nm处,表观摩尔吸收系数为7.75×10^4L·mol^-1·cm^-1,络合物的组成为6-NO2-BTAMB∶Cu=1∶1,铜浓度在0 ̄10μg/10ml范围内服从比尔定  相似文献   

8.
碱性氢化物发生—火焰原子吸收光谱法测定锡   总被引:7,自引:2,他引:7  
对Sn-NaOH-KBH4体系进行了系统研究,采用三乙醇胺-EDTA联合干扰抑制剂,可消除一定量铁及合金元素的干扰,对于锡含量小于0.01%的试样,用苯萃取锡后所有元素不干扰测定。测定液中锡量为0-4μg/10ml,呈线性关系,灵敏度为0.004mg/L/1%,检出限为0.008mg/L,测定钢中大于0.001%锡,结果满意。  相似文献   

9.
作以新研制的4-(6-甲基-2-苯并噻唑偶氮)间苯三酚为柱前衍生试剂,用含10mmol/L的pH6.80的HAc-NaAc缓冲溶液,10mmol/L TBA.Br和1×10^-4mol/LEDTA的甲醇-水溶液(78:22,V/V)作流动相,在C18柱上,11min内反相HPLC分离测定了Cr(Ⅵ),V(Ⅴ),Co(Ⅱ),Ni(Ⅱ)。当S/N=3时,其检出限分别是V(Ⅴ)5.45ng,Co(Ⅱ)  相似文献   

10.
在pH6.2的HAc-NaAc缓冲溶液中,在溴化十六烷基三甲基胺(CTMAB)存在下,Zr(Ⅳ)与7-碘-8-羟基喹啉-5-磺酸(H2QSI)及EDTA形成了四元荧光配合物,其组成为:Zr:H2QSI:EDTA:CTMAB=1:1:1:3。据此建立了锆的选择性好,灵敏度高的荧光测定方法,方法检测限为1.2ng/mL。锆的线性范围为1.6ng~1.0μg/mL。用于铜合金中微量锆的测定,结果令人满意  相似文献   

11.
用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.  相似文献   

12.
Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.  相似文献   

13.
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.  相似文献   

14.
The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.  相似文献   

15.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

16.
KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.  相似文献   

17.
The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.  相似文献   

18.
A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.  相似文献   

19.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.  相似文献   

20.
A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.  相似文献   

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