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铋-N-苯甲酰苯胲络合吸附波的研究 总被引:1,自引:0,他引:1
在pH5.6的0.2mol/L NH_4Ac-3×10~(14)mol/L N-苯甲酰苯胲(N-BPHA)底液中,用单扫示波极谱法可得到Bi(Ⅲ)的络合物吸附波,峰电位-0.33V(vs.SCE)左右。导数峰高与铋的浓度在5.0×10~(-8)~4.0×10~(-6)mol/L的范围内呈线性关系,检出限为2.0×10~(-8)mol/L。实验表明,该极谱峰属于络合物吸附波,测定其络合比为Bi(Ⅲ):N-BPHA=1:3。测定了该体系的吸附量;Bi(Ⅲ)-N-BPHA络合物在悬汞电极上的吸附符合Frumkin等温式,测得吸附系数β=2.87×10~5,吸引因子α=0.984。用于矿石中微量铋的测定。 相似文献
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在0.04Mol/L HAc-0.36Mol/L NaAc(pH5.7)和3.5×10~(-4)Mol/L 8-氨基喹啉(8-Aminoquinoline)溶液中,用单扫示波极谱法可得到In(Ⅲ)-8-氨基喹啉络合吸附波,峰电位在-0.78V处。其导数峰高与铟在5.0×10~(-8)-4.0×10~(-6)Mol/L范围内的浓度呈线性关系,最低检出限为2.0×10~(-8)Mol/L。研究确定该波为1∶1铟-8-氨基喹啉络合物的吸附波。测定了几种地球化学标准样品中的锢,结果满意。 相似文献
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示波极谱法同时测定痕量硒和砷 总被引:1,自引:0,他引:1
在盐酸-酒石酸锑钾介质中,Se(Ⅳ)在—0.59V(vs.SCE,下同)左右产生示波极谱峰,其二阶导数峰高IP″_(Se)与Se(Ⅳ)浓度在1.26×10~(-8)~1.26×10~(-4)mol·L~(-1)范围呈良好线性关系,Se(Ⅳ)检出下限为5.0×10~(-9)mol·L~(-1)。在相同底液中,当Se(Ⅳ)浓度大于2.5×10~(-6)mol·L~(-1)时,As(Ⅲ)在—0.79V左右也出现一良好极谱峰,其峰高IP″_(As)与As(Ⅲ)浓度在5.3×10~(-7)~2.6×10~(-4)mol·L~(-1)之间呈良好线性关系,As(Ⅲ)检出下限为2.7×10~(-7)mol·L~(-1)。Se(Ⅳ)、As(Ⅲ)两峰电位相差较大,可在同一底液中同时测定。曾用本法测定了煤飞灰标样(82201)中痕量硒和砷,结果与证书值相符。硒、砷加标回收率为95%~110%,还研究了Se(Ⅳ)、As(Ⅱ)极谱波性质。 相似文献
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在0.5 mol.L-1硫酸中,甲基橙与NO-2的亚硝化反应产物在极谱仪上于-0.20~-0.40 V(vs.SCE)获得灵敏的吸附波。二阶导数峰高与亚硝酸根浓度在4.0×10-5~5.0×10-2mg.L-1范围内呈线性关系,检出限为1.0×10-5mg.L-1,与普通极谱法相比较,降低了2~3个数量级。研究了吸附溶出波行为及反应机理,并利用该法测定了水样中亚硝酸根,RSD值小于3.5%,回收率在98.5%~100.4%之间。 相似文献
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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
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
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
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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
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Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
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
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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
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N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
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
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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
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《Tetrahedron》2014,70(21):3377-3384
The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative. 相似文献
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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