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1.
在0.06mol/L NaAc-HAc pH4.5的缓冲底液中,偶氮氯膦Ⅲ(CPAⅢ)在-0.25V(vs.Ag/AgCl)有一良好的微分脉冲极谱还原波,加入希土(RE)后期峰高电流(ip)降低,轻希土浓度在1×10^-6~6×10^-6moo/L,钇和重希土浓度在2×10^-7~3×10^-6mol/L范围中,ip的降低与浓度呈线性关系,表明CPAⅢ亦是可用的希土极谱分析试剂。实验证明它们是不可 相似文献
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TPPC在0.08mol/LCH3COONa和0.4mol/LCH3COOH(NaAc-HAc下同)底液条件下,在电位-1.57V附近产生一尖锐的导数波,峰高在3.7×10^-6-5.6×10^-5mol/L范围内呈线性关系,同时,讨论了极谱波的性质及电极反应机理。 相似文献
3.
铜—腺嘌呤络合物吸附波的研究 总被引:1,自引:0,他引:1
了在0.08mol/LNaAc~0.02mol/LHAc缓冲溶液铜与腺嘌呤(Ade)络合物的极谱行为,结果表明,扫描电压为-0.2V~-0.7V时铜-腺嘌呤络合物在单扫示波极谱上有一络合物吸附波,其一阶导数峰电位主-0.4V(vs.SCE),腺嘌呤浓度在1.0×10^-6~1.0×10^-5mol/L范围内与一阶导数波高呈良好的线性关系,检出限为1.0×10^-7mol/L,实验证明,该峰具有吸附 相似文献
4.
大黄酚在0.15mol/L HAc-NaAc(pH4.9)底液中,出现一灵敏的示波极谱导数峰,峰电位为-0.45V(vs,SCE),峰电流与大黄酚浓度在2.0×10^-7-5.0×10^-6mol/L范围内成线性关系,检测限为2.0×10^-6mol/L。用于生药大黄中大黄酚的测定,回收率为92.4%-108.4%。用多种电化学手段研究体系的电化学行为,测得电极反应电子数n=2。体系具有吸附性,并 相似文献
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本报道一种测定哌仑西平的单扫描示波极谱法,在0.1mol/LNH4Cl-NH3.H2O(pH8.0±0.1)缓冲液中,哌仑西平有一极谱还原波,其峰电位为-1.51V(vs.SCE),其一阶导数峰高与哌仑西闰浓度在6.6×10^-7-4.6×10^-6mol/L(r=0.9981)和6.6×10^-6-1.6×10^-5mol/L(r=0.9991)范围内有线性关系,检测限为3.4×10-7mol 相似文献
7.
单扫描示波极谱法测定甘草酸 总被引:3,自引:0,他引:3
本文报道测定甘草酸的单扫描法波极谱方法,在0.1mol/LNaAc-HAc(pH4.1±0.1)缓冲液中,甘草酸还原波峰电位为-1.38V(vs.SCE),峰高与其浓度在2.0×10^-6~1.0 ×10^-4mol/L范围内有线性关系,检测限为1.2×10^-6mol/L。甘氨酸,半胱氨酸等不干扰测定。应用本方法测定强力宁注射液中甘草酸含量,结果令人满意。本文还讨论了电极过程机理。 相似文献
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钒(Ⅴ)—向红菲咯啉的络合吸附波 总被引:10,自引:0,他引:10
在PH4.02的0.02mol/LHAc-NaAc介质中,研究了钒(Ⅴ)向红菲咯啉(BPT)的极谱行为。钒(Ⅴ)-BPT络合物在滴汞电采上于-0.36V得到一良好的吸附还原波,在聚乙烯醇(PVA)存在下,其二阶导数值一钒(Ⅴ)浓度在5.0×106-8-4.0×10^-6mol/L范围内呈线性关系;检出限可达9.0×10^-9mol/L。应用该法测定饮用水及碳素钢中微量钒,结果较好讨论了PVA的影响 相似文献
9.
本研究了一阶导数差示脉冲极谱法用于氢氯噻嗪及其制剂的定量分析。在0.002mol/L盐酸-0.002mol/L氯化钾底液中,于0.050V(vs.Ag/AgCl)处出现良好的一阶导数极谱峰,氢氯噻嗪浓度在0~6.0×10^-4mol/L范围内,与峰高呈线性关系,检测限为4.0×10^-9mol/L。方法操作简便、快速、灵敏、结果准确。 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
16.
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
20.
袁都奇 《化学物理学报(中文版)》2001,14(3):381-384
把有限时间热力学理论用于化学过程的研究,将会得到一系列新的结论,开展这方面的研究是很有意义的.文献[1]以燃料电池为例,在同时考虑化学反应及传热不可逆性的情况下,研究了燃料电池的性能界限,文献[2]指出了文献[1]计算化学反应及传热不可逆性而引起系统与有关环境的总熵产生率的错误以及由此而导致的结论所存在的问题,并进行了富有启发性的分析与讨论.但文献[2]对于系统与有关环境的总熵产生率的计算也是不正确的,由此得到的其它结论自然不能成立.本文将就此情况下系统与有关环境的总熵产生率的计算再次进行讨论,并给出电池功率和效率的有限时间热力学性能界限. 相似文献