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1.
Abstract

By interaction of mono- and dicarboil compounds with alkyl and arilmecaptances symmetric and and 1,1 - di(alkylthio) alkanes were synthesized. Reactions of these compounds with linear and cyclic scetals in the presence of mineral acids and cation- exchanged resins were studied. The main products are corresponding 1, alkylthioalkoxialkenes and 1,1-dialkoxialkanes. Kinetic investigations showed that the stage determiniung the process velocity is splitting of acetal group.  相似文献   

2.
薛祚霖 《应用化学》1991,8(1):18-22
采用循环伏安法研究了SO_2在多种电极(催化剂)上的电化学氧化过程。根据催化剂上是否存在表面氧化物以及SO_2吸附形态的不同,可将所研究的催化剂分为三种类型。第一类以Au、Pt、Pd为代表,第二类以Ru、Rh、Ir为代表,第三类以聚钴卟啉类N_4大环配合物为代表。并对SO_2在三类催化剂上反应的特点进行了讨论。  相似文献   

3.
ABSTRACT

This work presents unusual spectral behavior of poly(tricyanovinyl dimethylaniline) (1) in dilute solutions. A new conjugated polymer(1) was prepared from p-(tricyanovinyl)N,N-dimethylaniline via the use of a methylglucopyranoside reagent. It is observed that dilute solutions of 1 exhibit spectral features associated with aggregation. The associative interaction is studied by changing the salt concentration of LiBr in DMF solution, by changing the concentration of 1, and by varying the solvents. The association modifies the visible spectrum of 1 in dilute solution. Spectra of 1 in DMF solution exhibit an intense absorption maximum at 429 nm, which can be assigned to the side group, with tailing past 700 nm. With increasing concentration, a new absorption band arises between 480 nm and 700 nm. LiBr dissociates the aggregate to decrease the additional spectral features. The visible spectrum of 1 varies in different solvents. The spectrum of 1 in chloroform solution exhibits two maxima at 490 nm and 550 nm. The associative interaction presumably arises from a dipole–dipole interaction among pendant side groups. In DMF solution of 1 in the presence of p-chloranil, the spectrum shows a maximum at 429 nm with a distinct shoulder near 520 nm which does not orginate from 1 and p-chloranil(CA) itself.  相似文献   

4.
本文利用扫描遂道显微镜(STM)并辅以快速富立叶变换(FFT)和数据拟合等数学方法对电化学阳极氧化法制备的多孔硅(PS)的微结构及形貌进行了研究。同时研究了多孔硅的微结构与其发光性质和电化学性质的相互关系。研究表明,在其他条件不变情况下,随阳极氧化电流密度的增大,所形成的多孔硅的微孔向纵深延伸,多孔硅层增厚,微孔相连后形成的硅柱变细,发光强度增大,发光峰位明显蓝移,与单晶硅相比,多孔硅电极的平带电位明显负移,而电极电流在两极区内均增大。  相似文献   

5.
杂多化合物催化低级烷烃部分氧化的研究进展   总被引:3,自引:0,他引:3  
本文回顾了近年来杂多化合物用于低级烷烃的部分氧化的一些典型反应,对此提出了可能的反应机理,并预测了此类反应可能的改进方案和应用前景。  相似文献   

6.
本世纪五十年代以来,二过碘酸合铜(Ⅲ)和二过碲酸合铜(Ⅲ)配离子作为氧化剂在糖类、氨基酸。蛋白质、羧酸和醇类等的定量测定中得到了广泛的应用。近期Movius和Murthy等人进行了Cu(Ⅲ)对一元醇、醛等有机物的氧化反应动力学研究。Cu(Ⅲ)处于高价氧化态,这类反应体系又比较复杂,对这类反应体系进一步探讨有一定的意义,因为铜在许多包含有电子转移的生物化学过程中起着重要作用。本文在25℃,碱性介质中就Cu(Ⅲ)对乙二醇和丙二醇-1,2(统称,α-二醇,或α-diol)的氧化反应动力学进行了研究。  相似文献   

7.
Reactions of the title meso forms, (1R,2S)-1,2-di(2-furyl)-1,2-di(3-guaiazulenyl)ethane (1) and (1R,2S)-1,2-di(3-guaiazulenyl)-1,2-di(2-thienyl)ethane (2), with a two molar amount of TCNE in benzene at 25 °C for 5 h (for 1) and 48 h (for 2) under oxygen give new compounds, 2,2,3,3-tetracyano-4-(2-furyl)-8-isopropyl-6-methyl-1,4-dihydrocyclohepta[c,d]azulene (3) and 2,2,3,3-tetracyano-8-isopropyl-6-methyl-4-(2-thienyl)-1,4-dihydrocyclohepta[c,d]azulene (4), respectively, in 74 and 21% isolated yields. Comparative studies on the above reactions as well as the spectroscopic properties of the unique products 3 and 4, possessing interesting molecular structures, are reported and, further, a plausible reaction pathway for the formation of these products is described.  相似文献   

8.
用X光电子能谱(XPS)结合X衍射(XRD)和X荧光光谱(XFS)较深入地探讨了PVFc的热氧化分解过程.XPS研究表明,热氧化后铁原子价态明显升高,再根据Fe2p3/2谱的强度变化,说明薄膜表面氧化时经过某些中间阶段;XFS分析表明含铁量基本不变,证明上述变化仅发生在很薄的表面层.从XPS的研究得出PVFc中铁原子在170~180℃时开始被明显氧化;从XRD分析表明,氧化早期并未形成晶态氧化铁,直至约380℃时才开始形成结晶态的α-Fe2O3.  相似文献   

9.
聚醚氨酯的氧化及其接枝共聚合的研究   总被引:2,自引:0,他引:2  
本文研究了在聚醚氨酯表面上进行接枝共聚合的新方法。首先在聚醚氨酯薄膜上通过过氧化氢光氧化引入过氧化氢基,然后在还原剂亚铁盐或N,N-二甲基对甲苯胺的作用下引发丙烯酰胺接枝共聚合,反应具有低温快速的特点。产物经吸水性实验及扫描电子显微镜观察均证实了是一接枝共聚物。通过模型化合物的研究证明,接枝反应具有较高的选择性,接枝共聚占优势地发生在聚醚软段上,接枝地点很可能就在醚键旁的α-碳原子上。  相似文献   

10.
Abstract

The Schiff base N-2,4-dihydroxybenzal-D-glucosamine (L), and its Fe(III), Co(III), Cu(II) and Zn(II) complexes have been synthesized and characterized. Magnetic moments suggest that all complexes are high-spin. The Cu(II) chelate in DMF solution has a distorted tetrahedral structure, as shown by ESR and electronic spectra. Detailed studies have been made concerning the solution equilibrium of L with transition metal ions. Stabilities of the complexes are in accord with the Irving-Williams series.  相似文献   

11.
本文采用阳极差分脉冲伏安法同时测定微量DNA水解碱基鸟嘌呤和腺嘌呤的含量,从而建立了一种能对微量DNA进行快速测定G+C/A+T值的方法。本方法比层析分离后紫外吸收法灵敏度约高二个数量级,测定时间缩短到一小时半左右。经用德国小牛胸腺标准DNA进行实验,证明本方法准确可靠;并测定了大肠杆菌、棉铃虫等六种DNA的G+C/A+T值。  相似文献   

12.
By using GC-MS to analyze the extracts of source rocks, coal and crude oil samplesformed in different sedimentary environments in China, New Zealand and Australia, twenty-two compounds of five types of bicyclic alkanes have been dis covered in the samples. Thispaper makes an exposition of stereochemical structure, abundance and distributive features ofthese compounds and their relation to sedimentary environments and thermal evolution. Furt-thermore, it demonstrates how the abundance ratios of bicyclic alkanes to steranes and ter-panes, drimane to homodramane and the relative abundance of C_(15),C_(16),C_(12)-C_(14) series of bicyclic-alkane compounds can be used to judge and determine types of oil and gas forming environ-ments (the depositive environments of source rocks from which the oil and gas wereformed), characteristics of source rocks and degree of maturation.  相似文献   

13.
Abstract

Reactions of HBr with trans-[W(N2)2(dppe)PPh2Me)2] (1) (dppe = Ph2CH2CH2PPh2) result in protonation of coordinated N2 but no formation of ammonia or hydrazine. The tungsten-containing product depends upon the reaction conditions: (i) in MeOH, the product formed is [WBr(NNH2) (dppe)(PPh2Me)2]HBr2 (2) which converts to the hydride, [WBr2(H)(NNH2(dppe)(PPh2Me)](Br(3), with loss of phosphine in THF or CH2Cl2, (ii) in THF or CH2Cl2, the hydride (3) is formed directly. Reaction of 2 with Na2CO3 in MeOH results in the loss of HBr and the formation of the diazenido complex [WBr(NNH)(dppe)(PPh2Me)2] which reacts further with Na2CO3 in benzene under N2 to lose HBr and form a mixture of 1 and trans-[W(N2)(dppe)2]. The reaction of 1 with aqueous HF forms [WF(NNH2)(dppe)(PPh2Me)2]BF4. The X-ray photoelectron spectra of trans-[M(N2)2 (dppe)2], [MBr(NNH2)(dppe)2Br (M = Mo, W), [WCl(NNH2)(dppe)2]Cl, [WCl(N)(dppe)2]Cl and [WCl(NH) (dppe)2] are reported. In all of these complexes, nitrogen is in a highly reduced form.  相似文献   

14.
用程序升温脱附试验考察了LaMn_(1-y)Fe_yO_3型催化剂中B位元素对Co、CH_4氧化活性的影响。发现催化剂的活性与TPD谱上脱氧峰的位置及面积有关,同一催化剂对CO与CH_4的氧化活性中心并不一致。以γ-Al_2O_3为载体制得的锰系ABO_3型催化剂在浸渍微量氧化物助催化剂后,能使CO在130℃完全氧化,CH_4的氧化温度为300~500℃。  相似文献   

15.
Abstract

The kinetics and stability constants of l-tyrosine complexation with copper(II), cobalt(II) and nickel(II) have been studied in aqueous solution at 25° and ionic strength 0.1 M. The reactions are of the type M(HL)(3-n)+ n-1 + HL- ? M(HL)(2-n)+n(kn, forward rate constant; k-n, reverse rate constant); where M=Cu, Co or Ni, HL? refers to the anionic form of the ligand in which the hydroxyl group is protonated, and n=1 or 2. The stability constants (Kn=kn/k-n) of the mono and bis complexes of Cu2+, Co2+ and Ni2+ with l-tyrosine, determined by potentiometric pH titration are: Cu2+, log K1=7.90 ± 0.02, log K2=7.27 ± 0.03; Co2+, log K1=4.05 ± 0.02, log K2=3.78 ± 0.04; Ni2+, log K1=5.14 ± 0.02, log K2=4.41 ± 0.01. Kinetic measurements were made using the temperature-jump relaxation technique. The rate constants are: Cu2+, k1=(1.1 ± 0.1) × 109 M ?1 sec?1, k-1=(14 ± 3) sec?1, k2=(3.1 ± 0.6) × 108 M ?1 sec?1, k?2=(16 ± 4) sec?1; Co2+, k1=(1.3 ± 0.2) × 106 M ?1 sec?1, k-1=(1.1 ± 0.2) × 102 sec?1, k2=(1.5 ± 0.2) × 106 M ?1 sec?1, k-2=(2.5 ± 0.6) × 102 sec?1; Ni2+, k1=(1.4 ± 0.2) × 104 M ?1 sec?1, k-1=(0.10 ± 0.02) sec?1, k2=(2.4 ± 0.3) × 104 M ?1 sec?1, k-2=(0.94 ± 0.17) sec?1. It is concluded that l-tyrosine substitution reactions are normal. The presence of the phenyl hydroxyl group in l-tyrosine has no primary detectable influence on the forward rate constant, while its influence on the reverse rate constant is partially attributed to substituent effects on the basicity of the amine terminus.  相似文献   

16.
Complexes of ethylenediamine-N,N,N′,N′-tetraacetanilide (edtan, C34H36N6O14) with cobalt(II), nickel(II) and copper(II) in the solid state and in solution are reported for the first time. Thermodynamic data (stability constant, and derived Gibbs energy, enthalpy and entropy changes)for the 1 : 1 complexation of edtan with the metal ions at 298.15 K in water-saturated butan-1-ol gave the selectivity sequence log10Ks; Ni2+, 4.56±0.02; Cu2+, 4.41±0.01; Co2+, 4.18±0.04 as found from microcalorimetric titration studies. The entropies suggested that the structure of the 1 : 1 complex with copper(II) contains fewer chelate rings than those for nickel(II) and cobalt(II) (δcS0 : Cu-21.4, Co 5.7, Ni 3.9 J mol−1K−1). Solid complexes of the metal ions with edtan and perchlorate as the counter anion were prepared. For each, a complex with a 1 : 1 metal: edtan stoichiometry with non-coordinated perchlorate was isolated. The X-ray structure of [Cu(edtan)(H2O)][ClO4]2·1.5H2O (1) revealed a six-coordinate Cu centre with edtan acting as pentadentate ligand (2N, 3O) with the coordination sphere completed by an oxygen atom from water. In striking contrast to the Cu complex, the Co centre in [Co(edtan)(H2O)][ClO4]2·H2O·0.5C2H5OH (2) is seven-coordinate with hexadentate edtan (2N, 4O) and one coordinated water molecule. There is thus an excellent confirmation of the results obtained from the microcalometric study in that edtan forms four chelate rings to Cu but five to Co in the solid state. The ability of the ligand to extract metal ions from water to the water-saturated butan-1-ol phase was assessed from distribution data as a function of the aqueous phase hydrogen ion concentration and of the ligand concentration in the organic phase. The data showed that Cu2+ is selectively extracted over a wide range of aqeous phase hydrogen ion concentrations.  相似文献   

17.
合成了侧链带有芴的聚丙烯酸芴酯(PFM),在含40%三氟化硼乙醚的二氯甲烷混合电解质溶液中,直接阳极氧化PFM获得了自支撑交联网状的聚(聚丙烯酸芴酯)(CPFM)薄膜.通过UV-Vis、FTIR和1H-NMR对CPFM结构进行了表征.荧光光谱表明得到的聚合物薄膜CPFM在415nm附近处具有强的荧光发射峰,表明聚丙烯酸结构的引入没有影响聚芴的蓝色发光性能并有利于提高聚合物薄膜的力学性能.TGA表明得到的CPFM薄膜具有良好的热稳定性。  相似文献   

18.
A polymer film of tryptophan was obtained at a glassy carbon electrode (GC) by cyclic voltammetry. The cyclic voltammograms of the polymer film electrode(poly-Try GC) exhibited two redox waves. After incorporation of Ni(II), the electrode (poly-Ni(II) Try/GC) was greatly improved in catalytic activity. The potential 0.65 V of methanol oxidation at the poly-Ni(II)Try/GC is much more negative than the potential at the poly-Try/GC and at the bare glassy carbon (GC) electrode in 0.01 mol/L NaOH.  相似文献   

19.
为了研究抑制剂对银核和硫化银核的不同作用,本工作考察了1-苯基-5-巯基四氮唑(PMT)和苯并三氮唑(BTA)作为抑制剂在银核和硫化银核上物理显影的阳极抑制和解抑制效应.实验结果表明: 1)PMT和BTA对Ag核和银离子过量时制得的硫化银核,Ag2S(Ag),的显影催化活性都有不同程度的抑制作用,而对硫离子过量时制得的硫化银核,Ag2S(S),无明显的抑制作用,这可能是由于过量硫离子在硫化银核上的吸附要强于这两种抑制剂;2)S2O32-或I-离子的存在对BTA在Ag核上有解抑制作用,不仅可恢复甚至提高Ag核的显影催化活性,而对Ag2S核的抑制作用无明显影响; 3)与BTA不同,S2O32-或I-离子对PMT在Ag核上没有解抑制作用,对Ag2S(Ag)核的抑制作用还稍有增强,而对Ag2S(S)核稍有减弱;4)银溶胶中的表面增强拉曼谱(SERS)测量证实:BTA在Ag核上的吸附导致Ag核显影催化活性的下降,加入S2O32-或I-离子后致使BTA的SERS信号消失则意味着BTA在银核表面的脱附.以上这些结果说明阳极抑制机理在抑制效应中有重要作用.  相似文献   

20.
本文通过监测氧化中间体半醌(S~+)的吸光度变化跟踪反应进程。用初始速率法处理得到了HAc-NaAc介质中Fe(CN)_6~(3-)(Ox′)催化[CO~Ⅲ(NH_3)_5Cl]~(2+)(Ox)氧化CD-4遵循下列动力学方程: d[S~+]/dt=k_(obs).[Ox′]~(0.90)[Ox]~(0.85)认为Fe(CN)_6~(3-)的再生过程是整个反应的决速步骤。估算了决速步的速率常数k(298K)、活化焓△H~(0≠)和活化熵分别为1.92dm~3·mol~(-1)s~(-1)、23.1kcal/mol和20.5cal/mol.K。以TEPPD代替CD-4、以Fe(CN)_6~(4-)代替Fe(CN)_6~(3-)的实验结果支持了所提出的再生机理的合理性。 实验也得到了[Co~Ⅲen_2Cl_2]~+直接氧化CD-4或TEPPD的动力学方程。测定了反应的活化能。认为PPD氧化为半醌是反应的决速步骤。[Co~Ⅲ(NH_3)_6]~(3+)、[Co~Ⅲ(NH_3)_5Cl]~(2+),[CoⅢen_3]~(3+)、[CoⅢen_2Cl_2]~+氧化PPD的实验结果表明,钴(Ⅲ)络合物的取代活性增加,氧化活性亦增加。  相似文献   

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