氯化四-(对氯苯基)铁卟啉催化氧化邻硝基甲苯的表观动力学研究

研究了氯化四-(对氯苯基)铁卟啉T(p-Cl)PPFeCl催化氧化邻硝基甲苯的表观动力学.在确定邻硝基苯甲醛和邻硝基苯甲酸为主要产物的基础上,建立了连串反应模型和速度方程.根据不同温度条件下所测得的反应速率常数,确立了邻硝基甲苯氧化生成邻硝基苯甲醛的第一步反应为一级反应,且表观活化能为99.5 kJ/mol;而邻硝基苯甲醛氧化生成邻硝基苯甲酸的第二步反应为1/2级反应,且表观活化能为82.9 kJ/mol.通过比较两步反应的表观活化能和反应速率常数,发现升高温度有利于邻硝基苯甲醛的生成,且反应速率较快.     

催化动力学光度法测定痕量亚硝酸根的研究进展

综述了近年来催化动力学光度法测定痕量亚硝酸根的研究进展。具体内容包括:催化褪色动力学光度法测定痕量亚硝酸根的研究进展;催化荧光法测定痕量亚硝酸根的研究进展。评述内容包括指示反应及其条件、方法的检出限、线性范围、应用及干扰情况等,并探讨和展望了催化动力学光度法未来的研究方向和发展趋势。     

鸡蛋白四苯基锰卟啉催化乙醇氧化性能研究

使用鸡蛋蛋白(HEW)作为载体,制备鸡蛋白四苯基锰卟啉(Mn-TPP/HEW)催化剂并进行表征.考察该催化剂在不同时间、温度和压力等反应条件下的催化活性及其催化氧化乙醇生成乙醛和乙酸的能力.在最佳反应条件下,该催化剂得到的乙醇转化率和选择性(乙醛+乙酸)分别为18.3%、70.5%.并初步提出了可能的催化反应机理.     

四(对-磺酸钠苯基)卟啉的提纯

改进了四（对－磺酸钠苯基）卟啉（TPPS4）的合成,特别是提纯方法。以四苯基卟啉为原料,经氢横酸或浓硫酸处理合成了TPPS4,详细介绍了后处理过程。     

罗丹明B催化光度法测定亚硝酸根的研究

利用在硫酸介质中亚硝酸根催化溴酸钾氧化罗丹明B的褪色反应,建立了测定亚硝酸根的新方法,该方法的检出限为0.14μg/mL,线性范围为0.2~0.5μg/mL,本方法可用于水及蔬菜中痕量亚硝酸根测定。     

催化光度法测定微量亚硝酸根的研究

基于在0.4 mol/L硫酸介质中,亚硝酸根对溴酸钾氧化乙基橙褪色反应的催化作用,建立了一种在恒温水浴50oC下测定亚硝酸根含量的新方法。在508 nm处,亚硝酸根的含量在0.013～0.2μg/mL范围内与乙基橙吸光度的减小(lgA0/A)呈线性关系,检出限为0.02μg/mL。研究发现温度仅对反应的初始速率有较大的影响,但在8～15 min反应时间范围内,ΔA的值趋于恒定,温度及时间几乎无影响,克服了实验中ΔA随时间和温度变化的影响。本方法简便快速,灵敏度及选择性较高,用于环境水样中痕量NO2-的测定,结果满意。     

新型尾式谷氨酸四苯基卟啉锰(Ⅲ)催化烯烃环氧化研究

研究了新型尾式谷氨酸四苯基卟啉锰（Ⅲ）［Ｍｎ（Ｇｌｕ－ＴＰＰ）Ｃｌ］与锌粉（Ｚｎ）、乙酸（ＣＨ３ＣＯＯＨ）、分子氧（Ｏ２）和咪唑（Ｉｍ）组成的氧化模拟体系催化烯烃的环氧化反应。测定了氧化反应体系吸氧动力学曲线。结果表明,体系的最高吸氧速度高达１．５ｍＬ·ｍｉｎ－１,环氧化产物收率（Ｚｎ％）可达５９．２％。     

Meso-四(4-羧基苯基)卟啉及其金属配合物的合成及光谱性质研究

文章用Adler法将吡咯和羧基苯甲醛反应合成了5,10,15,20-四(4-羧基苯基)卟啉(TCPP),用反复调pH法得到了较纯净的TCPP,解决了TCPP分离纯化困难的问题;并合成了其Zn(II)和Co(II)的配合物,并利用紫外,1H-NMR荧光,红外和EPR对其光谱进行了研究。     

5,10,15,20-四(4-羧基苯基)卟啉(TCPP)检测水体痕量Hg~(2+)的研究

由于羧基卟啉在水中良好的溶解性及对Hg⁽²⁺⁾的高亲和性,利用5,10,15,20-四(4-羧基苯基)卟啉与Hg(2+)的高亲和性,利用5,10,15,20-四(4-羧基苯基)卟啉与Hg⁽²⁺⁾反应前后的荧光特性变化,实现水体Hg(2+)反应前后的荧光特性变化,实现水体Hg⁽²⁺⁾的痕量检测。结果显示,该探针与Hg(2+)的痕量检测。结果显示,该探针与Hg⁽²⁺⁾具有良好的配位性,且检测前后体系出现的颜色变化具有可视性。在中性条件下,四羧基卟啉荧光被Hg(2+)具有良好的配位性,且检测前后体系出现的颜色变化具有可视性。在中性条件下,四羧基卟啉荧光被Hg⁽²⁺⁾猝灭,荧光强度与汞离子浓度之间存在良好的指数函数关系,相关系数为0.998。因此,5,10,15,20-四(4-羧基苯基)卟啉可作为一种高效、可靠的探针用于水体中Hg(2+)猝灭,荧光强度与汞离子浓度之间存在良好的指数函数关系,相关系数为0.998。因此,5,10,15,20-四(4-羧基苯基)卟啉可作为一种高效、可靠的探针用于水体中Hg⁽²⁺⁾的痕量检测。     

5,10,15,20-四(4-羧基苯基)卟啉(TCPP)检测水体痕量Hg~(2+)的研究

由于羧基卟啉在水中良好的溶解性及对Hg~(2+)的高亲和性,利用5,10,15,20-四(4-羧基苯基)卟啉与Hg~(2+)反应前后的荧光特性变化,实现水体Hg~(2+)的痕量检测。结果显示,该探针与Hg~(2+)具有良好的配位性,且检测前后体系出现的颜色变化具有可视性。在中性条件下,四羧基卟啉荧光被Hg~(2+)猝灭,荧光强度与汞离子浓度之间存在良好的指数函数关系,相关系数为0.998。因此,5,10,15,20-四(4-羧基苯基)卟啉可作为一种高效、可靠的探针用于水体中Hg~(2+)的痕量检测。     

N-对羧基苯基马来酰亚胺的制备与表征

以顺丁烯二酸酐(MAn)和对氨基苯甲酸(P-AA)为原料、乙酸乙酯为溶剂、无水醋酸钠为脱水催化剂合成了N-对羧基苯基马来酰亚胺(P-CPMI)，并采用元素分析、核磁共振、红外光谱对目标产物的结构进行了表征。     

生物催化氧化锰和黄铁矿的共同浸出

为了探索在微生物存在的条件下氧化锰和硫化矿共同浸出的特点,进行了氧化亚铁硫杆菌在好氧和厌氧条件下对FeS2-MnO2-H2SO4体系的催化浸出实验研究。结果表明,在好氧条件和厌氧条件下,氧化亚铁硫杆菌均可以催化FeS2-MnO2-H2SO4体系的浸出。好氧条件下利于FeS2的浸出,浸出36 h时,在MnO2:FeS2质量比为1:1、5:1、6:1时的浸出率分别为:25.34%、82.89%和82.58%。厌氧条件下,利于MnO2的浸出,浸出36 h时,在MnO2:FeS2质量比为1:1、5:1、6:1时的浸出率分别为:87.76%、85.35%和75.09%。浸出机理是氧化亚铁硫杆菌催化铁离子在二价和三价之间的循环转化,根据实验结果提出了好氧和厌氧条件下,FeS2-MnO2-H2SO4体系的两矿反应模型。     

表面活性剂和盐酸高效催化二吲哚甲烷的合成

二吲哚甲烷及其衍生物是很多生理活性分子的重要构成部分,我们开发了一种新的合成二吲哚甲烷及其衍生物的方法。在10mol%的十二烷基苯磺酸钠和盐酸的共同催化下,吲哚和醛、酮在60℃下能顺利、高效的发生反应得到二吲哚甲烷衍生物。在最优的反应条件下,我们对醛和酮的适用范围进行了考察。催化剂循环使用研究表明,该催化体系在循环使用五次后仍能保持很好的催化活性。     

Radiolysis Studies of Oxidation and Nitration of Tyrosine and Some Other Biological Targets by Peroxynitrite-Derived Radicals

The widespread interest in free radicals in biology extends far beyond the effects of ionizing radiation, with recent attention largely focusing on reactions of free radicals derived from peroxynitrite (i.e., hydroxyl, nitrogen dioxide, and carbonate radicals). These radicals can easily be generated individually by reactions of radiolytically-produced radicals in aqueous solutions and their reactions can be monitored either in real time or by analysis of products. This review first describes the general principles of selective radical generation by radiolysis, the yields of individual species, the advantages and limitations of either pulsed or continuous radiolysis, and the quantitation of oxidizing power of radicals by electrode potentials. Some key reactions of peroxynitrite-derived radicals with potential biological targets are then discussed, including the characterization of reactions of tyrosine with a model alkoxyl radical, reactions of tyrosyl radicals with nitric oxide, and routes to nitrotyrosine formation. This is followed by a brief outline of studies involving the reactions of peroxynitrite-derived radicals with lipoic acid/dihydrolipoic acid, hydrogen sulphide, and the metal chelator desferrioxamine. For biological diagnostic probes such as ‘spin traps’ to be used with confidence, their reactivities with radical species have to be characterized, and the application of radiolysis methods in this context is also illustrated.     

Direct Coupling Reactions of Alkynylsilanes Catalyzed by Palladium(II) Chloride and a Di(2‐pyridyl)methylamine‐Derived Palladium(II) Chloride Complex in Water and in NMP

Symmetrical internal alkynes can be prepared either by diarylation of mono‐ and bis(trimethylsilyl)acetylene (TMSA and BTMSA) catalyzed by ligand‐less palladium(II) chloride or by a di(2‐pyridyl)methylamine‐derived palladium(II ) chloride complex 1 (typical 0.1–1 mol % of Pd loading) in water using pyrrolidine as base and tetra‐n‐butylammonium bromide as additive. Alternatively, this same process is performed in NMP in the presence of tetra‐n‐butylammonium acetate (TBAA) as base with even lower Pd loadings (0.001–1 mol % Pd). The same reaction conditions are applied to the synthesis of unsymmetrical internal alkynes by monoarylation of silylated terminal alkynes. Aryl iodides can be coupled with TMSA, BTMSA and silylated terminal alkynes under heating or at room temperature, whereas for aryl bromides couplings are performed under water reflux or at 110 °C in the case of NMP. Complex 1 can be reused during several cycles either in water or in NMP without loss of catalytic activity. These simple reaction conditions allow the preparation of internal alkynes without secondary products, most probably by succesive protiodesilylation‐Sonogashira coupling.     

The Radical Versus Non-radical Reactive Intermediates in the Iron(III) Porphyrin Catalyzed Oxidation Reactions by Hydroperoxides, Hydrogen Peroxide and Iodosylarene

In the catalytic reaction of an iron(III) porphyrin with t-BuOOH, CumOOH, H₂O₂ and C₆F₅IO, cyclohexene was used as a probe substrate. The selective hydroxylation of cyclohexene by hydroperoxides proceeds through radical path and this has been utilized for successful dioxygen activation/autooxidation. For other oxidants epoxide was the major product and the reactions proceed through non-radical path.     

Hydrosilylation of Aldehydes and Ketones Catalyzed by Half‐Sandwich Manganese(I) N‐Heterocyclic Carbene Complexes

Easily available manganese(I) N‐heterocyclic carbene (NHC) complexes, Cp(CO)₂Mn(NHC), obtained in one step from industrially produced cymantrene, were evaluated as pre‐catalysts in the hydrosilylation of carbonyl compounds under UV irradiation. Complexes with NHC ligands incorporating at least one mesityl group led to the most active and selective catalytic systems. A variety of aldehydes (13 examples) and ketones (11 examples) were efficiently reduced under mild conditions [Cp(CO)₂Mn(IMes) (1 mol%), Ph₂SiH₂ (1.5 equiv.), hν (350 nm), toluene, 25 °C, 1–24 h] with good functional group tolerance.

     

Reactions Catalyzed by Pentacyanocobaltate(II)

As early as a century ago Descamps[1] noted that solutions of cobaltous salts evolved hydrogen in the presence of cyanide ion. Yet it was not until 1942[2,3] that Iguchi observed that such solutions were able to absorb molecular hydrogen and transfer it to substrates.     

Peroxyacetic Acid Oxidation of Olefins and Alkanes Catalyzed by a Dinuclear Manganese(IV) Complex with 1,4,7-trimethyl-1,4,7-triazacyclononane

Natural terpenes, (−)-limonene and (+)-carvone, can be epoxidized by peroxyacetic acid (PAA) at room temperature if a dinuclear manganese(IV) complex with 1,4,7-trimethyl-1,4,7-triazacyclononane (L), [Mn₂L₂O₃] [PF₆]₂, is used as a catalyst. The total yield of the epoxides based on the consumed olefins are 97 and 95%, respectively. A kinetic study of the dec-1-ene and cyclohexane oxygenations including the investigation of their simultaneous competitive oxidation was carried out. The olefin epoxidation rate does not depend on dec-1-ene concentration and the dec-1-ene concentration does not affect the rate of cyclohexane oxidation. The cyclohexane oxidation rate is proportional to the alkane concentration. The kinetic analysis led to the conclusion that two species X ₁ and X ₂ are generated in the system, and there is no their mutual interconversion. The rate equation for the dec-1-ene epoxidation was proposed: W = k ₊₁[cat][PAA], where cat is the initial manganese complex or its derivative, and the constant was determined: k ₊₁ = 3.5 mol⁻¹ dm³ s⁻¹. Species X ₁ is apparently an effectively epoxidizing manganese peroxo derivative whereas species X ₂ is an alkane hydroxylating manganese oxo complex.