醛的自氧化振荡反应

1983年 Jensen 与 Roelofs 等报道了苯甲醛自氧化反应中出现的化学振荡现象。我们还观察到苯甲醛、取代苯甲醛和许多脂肪醛的自氧化振荡反应,实验方法与文献[3]相似。反应在具有电磁搅拌的恒温反应器中进行,以醋酸水溶液(冰醋酸与水的体积比为9∶1)和     

Me[14]-N4大环四烯镍(Ⅱ)催化、BrO3-氧化丙酮酸的振荡化学反

本文报道了一种以２，３，９，１０－四甲基－１，４，８，１１－四氮杂环十四－１，３，８，１０－四烯镍（Ⅱ）配合物［Ｎｉ（ㄔＩＭ）］＾２＋为催化剂、ＮａＢｒＯ３为氧化剂、丙酮酸为有机废物、稀硫酸为介质的振荡化学反应新体系。对该体系的振荡特性进行了描述。研究了Ａｇ＾＋、Ｈｇ＾２＋、还原性物质、自由基抑制剂、四氯化碳以及温度对振荡的影响。     

苯甲醛衍生物的结构与其半波电位关系的研究

以半经验分子轨道方法计算苯甲醛衍生物的分子结构参数，以多元线性回归方法研究了苯甲醛衍生物的半波电位与其分子结构参数间的关系。研究发现，在所选择的２３个分子结构参数中，基态双中心总能量（ＥＴ（ｔｗｏ）、电离势（Ｉｐ）及分子的生成热（Ｈｆ）与其半波电位有较好的相关性。其回归方程为：ｙ＝－５．４２３２＋０．５４７７８Ｉｐ－３．３３１＊１０＾－３Ｅｔ（ｔｗｏ）－１．６７０＊１０＾－３Ｈｆ（ｒＲＣ＝０．９２     

乙酰乙酸乙酯—BR化学振荡反应的研究

本文首次报道了乙酰乙酸乙酯－ＩＯ３＾－－Ｈ２Ｏ２－Ｍｎ＾２＋－Ｈ２ＳＯ４体系的化学振荡反应。研究了各种因素对振荡反应的影响，测定了最佳反应条件及振荡反应的浓度范围。研究了温度变化对振荡反应的影响，并计算了振荡反应的表观活化能，对振荡反应产物进行了分析，并测定了体系主要反应的计量关系，采用ＵＶ法对金属离子的作用和催化机理作了研究，探讨了ＢＲ反应中Ｉ２的产生机理及消耗机理，对体系中有关反应物的作用作了     

硫脲氧化的非线性动力学研究——H2O2—SC（NH2）2—Cu^2＋反应体系

研究了Ｈ２Ｏ２－ＳＣ（ＮＨ２）２－Ｃｕ＾２＋－Ｈ＾＋反应体系在封闭条件下以及在ＣＳＴＲ中的振荡行为，体系在封闭条件下出现单峰振荡行为，其振幅和诱导期与反应温度，（Ｈ２Ｏ２），（ＳＣ（ＮＨ２）２）等有关，在ＣＳＴＲ中体系的Ｐｔ电极电位，铜离子选择性电极电位以及ｐＨ值均显著稳定的周期性振荡，考察期振荡过程的流速序列，发现在低流速下的出现周期性复杂振荡，体系没有双稳态出现。     

V-Ag-Ni系氧化物的表面氧性质与甲苯选择性氧化的催化性能

制备了一系列Ｖ，Ａｇ，Ｎｉ原子比不同的三元氧化物，应用ＴＰＤ－ＭＳ技术研究了样品表面氧的性质，并测定了甲苯选择性氧化生成苯甲醛的催化活性。实验结果表明，样品表面存在有多种吸附的氧物种。在脱附温度＜９００℃：当Ｎｉ含量对Ａｇ（或Ｖ）的原子比为０．２５或０．５０时，仅在低温处出现有表面的Ｏ＾－和Ｏ＾２＾－两种氧物种的脱附峰；当Ｎｉ含量对Ａｇ（或Ｖ）的原子比增高到＞０．７５时，除有表面的Ｏ＾－和Ｏ＾２＾     

添加Ag或Ag,Ni的V2O5表面氧性质及催化性能研究

用ＴＰＤ－ＭＳ及甲苯选择氧化活性测定等方法研究了Ｖ２Ｏ５和添加Ａｇ或Ａｇ，Ｎｉ的３种样品的表面氧和晶格氧的热脱附性能及催化活性。结果表明，在Ｖ２Ｏ５中加入Ｎｇ或Ａｇ，Ｎｉ后，样品表面上的Ｏ＾－和Ｏ＾２－氧物种的脱附活化能明显降低。添加Ａｇ，Ｎｉ样品表面氧的脱附活化能最低，而苯甲醛生成的选择性最高，在Ｖ２Ｏ５和含有Ａｇ，Ｎｉ的样品中，温度为９６８和７３４℃时，均依次出现以晶格氧（Ｏ＾２－）脱附为主的     

氟化物催化硅氢化合物和取代酚的脱氢偶联反应

通过等摩尔竞争反应研究了氟化物催化的硅氢化合物和取代酚的脱氢偶联反应机理。研究表明，ｐ－ＸＣ６Ｈ４ＯＨ在反应中的取代基效应与氟化物催化取代苯甲醛ｐ－ＸＣ６Ｈ４ＣＨＯ的硅氢化反应中的不同，这表明它们的反应机理存在差异，在这两种反应中，虽然Ｆ＾－对Ｓｉ的配位都促进了硅氢化合物中的Ｈ对底物中带正电荷原子的亲核进攻，但是在催化酚解反应中，由于没有四中心过渡态的形成，因此下一步取代酚中的氧原子对Ｆ＾－配位的     

N—对甲苯磺酰基—α—氨基膦酸及其单酯的合成及活性研究

用＾３１Ｐ ＮＭＲ谱跟踪反应的方法，研究了对甲苯磺酰胺与取代苯甲醛及三氯化磷（或烷氧基二氯化磷）在乙酰氯为溶剂的条件下的类Ｍａｎｎｉｃｈ反应的机理，找到了合成标题化合物的简单方法。初步生物活性测试表明其中某些化合物具有较好的抗烟草花叶病毒活性。     

双—全氟烷基氮氧自由基从取代苯甲醛的攫氢反应—用EPR方法…

ＲＦＮ（Ｏ＾．）ＲＦ和ＲＦＮＯ的Ｆ１１３溶液在室温下与一系列的对位取代苯甲醛反应，得到稳定的对位取代苯甲酰基全氟烷基氮氧自由基。由△ａＮ和△ａ＾βＦ的σ单参数相关以及△ａＮ与σ和σ＾．双参数相关表明：极性效应是影响氟烷基酰基氮氧自由基中氮原子自旋密度变化的主要因素，而自旋离域效应的影响是很小的。     

Autoxidation of terpenic aldehydes—II

The influence of steric factors on the autoxidation of aldehydes having tertiary formyl groups has been investigated. These afford nor-derivatives by loss of carbon monoxide, and carboxylic acids. Steric interactions have been shown to affect strongly the ratio between carboxylic acid and nor-derivatives and, in addition, to increase the autoxidation rate. For the first time, formation of formates from aldehydes by autoxidation conditions, has been demonstrated.     

芦荟大黄素的电化学研究

用单扫示波极谱法研究了芦荟大黄素的电化学行为。在５％Ｎａ２ＣＯ３＋５％ＮａＯＨ（９＋１）底液中，芦荟大黄素于－０．８４Ｖ（Ｐ１）和－０．９７Ｖ（Ｐ２）处产生两个示波极谱峰，利用Ｐ１可测定芦荟大黄素，线性范围为 ０．１１－２４ｍｇ／Ｌ和３．０－２８．６ｍｇ／Ｌ，检测限为０．０６ｍｇ／Ｌ。将该法应用于中药大黄中的芦荟大黄素的测定，结果满意。另外，讨论了芦荟大黄素清除由邻苯三酚自氧化产生的超氧自由基（Ｏ２）的作用。     

丹参素自氧化与促氧化机理

采用过氧化氢电极与电子自旋共振(ESR)技术对不同pH值条件下丹参素的自氧化及Cu2+对丹参素的促氧化反应机理进行了研究.实验结果发现:在碱性条件下(pH=8.5),丹参素自氧化作用异常显著,氧化首先生成O2-·,随后可歧化为H2O2,并且Cu2+对H2O2信号增强也起着显著的促进作用;在弱酸性条件下(pH=6.5),丹参素自氧化过程受到抑制,主要表现为少许Cu2+的促氧化作用;而在生理条件下(pH=7.4),丹参素的自氧化过程缓慢,有少量H2O2生成,并且Cu2+的促氧化作用非常有限.因此,当丹参素作为一种高效抗氧化剂药用时,其自身的自氧化与金属离子促氧化作用都应有所考虑,尤其在偏碱性体液中,更易产生大量的超氧阴离子自由基,并对生物机体造成某种损害.     

酪氨酸-溴酸钾-硫酸-丙酮在三邻菲啰啉合铁(Ⅱ)催化下的B-Z振荡反应

研究了酪氨酸-溴酸钾-硫酸-丙酮在三邻菲啰啉合铁(Ⅱ)催化下的化学振荡反应,对振荡的影响因素进行了研究和讨论.运用正交实验法确立了振荡反应进行的浓度范围,得到一个40多次振荡寿命为60 min的振荡波.获得振荡的诱导期和周期与反应物浓度之间的变化趋势曲线,以及振荡反应在诱导期和振荡期的表观活化能分别为Ein=49.0 kJ/mol和E=57.0 kJ/mol.根据反应过程中的现象和实验数据,建立了振荡反应的模型和反应机理,确定[Br-]是振荡反应自发进行的关键因素.     

Heterocyclic tautomerisms. II. An investigation of the 2-arylbenzothiazoline 2-(benzylideneamino)thiophenol tautomerism. Part 2

The reaction between 4-mercaptoaniline and various aromatic aldehydes was studied as a model system in order to determine which type of substitution on the aryl group in 2-arylbenzothiazolines (1) might give rise to the greatest possible stabilization of the hypothetical 2-(benzylideneamino)thiophenol tautomer (II). Regardless of electronic effect of substituents, most aldehydes reacted with 4-mercaptoaniline to form poly[4-(benzylideneamino)thiophenols] (III). Aromatic aldehydes substituted in the 2 position with the hydroxyl function reacted to form the stable, monomeric 4-(benzylideneamino)thiophenols (IV). This stabilization in the monomeric state is presumed to be due to the hydrogen-bonded nature of these compounds (V). Both monomeric and polymeric compounds reacted with benzalacetophenone in the presence of a basic catalyst in the manner to be expected of the 4-(benzylideneamino)thiophenol structure (IV) yielding correspondingly substituted 1,3-diphenyl-1-[4-(benzylideneamino)phenylthio]-3-propanones (VI).     

Autoxidation of terpenic aldehydes—I

The autoxidation reaction of diterpenic 4-axial-aldehyde torulosal (1b) has been studied. Naturally occurring 4-hydroxy-nor-diterpenes have been proved to be artefacts arising in the autoxidation of the corresponding 4-aldehyde. Hydroperoxides (1d) and (2d), the main autoxidation products of 1b, have also been postulated as intermediates in the formation of 4-hydroxy-nor-diterpenes (1a and 2a).     

Novel vanadium-catalyzed oxidation of alcohols to aldehydes and ketones under atmospheric oxygen

[reaction: see text] Oxidation of alcohols to aldehydes and ketones has been studied in high yields using atmospheric oxygen and a catalytic amount of V2O5 in toluene under heating (ca. 100 degrees C). Secondary alcohols can be chemoselectively converted into ketones in the presence of primary hydroxy groups.     

Catalytic hydrogen transfer over MgO, VI dehydrogenation of 2-ethyl-1-hexanol

The dehydrogenation of 2-ethyl-l-hexanol to 2-ethylhexanal by hydrogen exchange with aliphatic aldehydes has been studied over MgO. As hydrogen acceptors acetaldehyde, propionaldehyde and isobutyraldehyde were used. Reaction with propionaldehyde was found to be an effective synthetic route for 2-ethylhexanal preparation, whereas during reactions with acetaldehyde and isobutyraldehyde a gradual catalyst deactivation vs. time-on-stream was observed.Part V in Stud. Surf. Sci. Catal., 78, 631 (1993) Fine Chemicals III), and references therein.     

Kinetic fluorimetric determination of traces of vanadium(V) by means of a catalysed autoxidation process

A kinetic method for determination of traces of vanadium(V) (0.04-0.5 ppm) is described. It is based on the catalytic action of vanadate in the autoxidation of sodium 4,8-diamino-1,5-dihydroxyanthraquinone-2,6-disulphonate, giving rise to kinetic curves characterized by an induction period before the appearance of a product exhibiting an intense red fluorescence in acidic solution. This product has been investigated and the experimental variables and interferences have been studied.     

Oxidation Catalysis by an Aerobically Generated Dess–Martin Periodinane Analogue

Hypervalent iodine(V) reagents, such as Dess–Martin periodinane (DMP) and 2‐iodoxybenzoic acid (IBX), are broadly useful oxidants in chemical synthesis. Development of strategies to generate these reagents from dioxygen (O₂) would immediately enable use of O₂ as a terminal oxidant in a broad array of substrate oxidation reactions. Recently we disclosed the aerobic synthesis of I(III) reagents by intercepting reactive oxidants generated during aldehyde autoxidation. In this work, aerobic oxidation of iodobenzenes is coupled with disproportionation of the initially generated I(III) compounds to generate I(V) reagents. The aerobically generated I(V) reagents exhibit substrate oxidation chemistry analogous to that of DMP. The developed aerobic generation of I(V) has enabled the first application of I(V) intermediates in aerobic oxidation catalysis.