Mannich反应合成3,6(8)-二取代-2,4-二氢-1,3-苯并(口恶)嗪及其杀菌活性

以取代苯酚、多聚甲醛和取代苯胺为原料,在无催化剂的条件下,通过Mannich缩合反应合成了一系列新型3,6(8)-二取代-2,4-二氢-1,3-苯并(口恶)嗪类化合物.结果表明,取代苯酚和取代苯胺的取代基为供电子基时,合成产物的产率高于吸电子取代基的.产物的结构用1H NMR、13C NMR、IR和MS等进行了表征.初步测试了目标化合物的杀菌活性,部分化合物具有较好的杀菌活性.当浓度为25 mg/L时,化合物4j和4d对菌核病菌的抑制率分别为86.1％和81.5％,化合物4i对灰霉病菌的抑制率为81.6％.     

取代基结构-活性关系对电化学降解取代苯胺的影响

以Na2SO4为支持电解质, 使用Ti/PbO2电极, 研究了带有推电子基(—CH3)和吸电子基(—NO2, —Cl)的邻或对位取代基苯胺类化合物的电催化氧化降解过程. 研究结果表明, 带有取代基苯胺类化合物的氧化降解是在羟基自由基进攻下生成氨基酚类化合物, 然后在电极表面失去电子生成苯醌继续氧化的过程. 带有推电子基团苯胺的电催化降解速度比带有吸电子基团的苯胺降解速度快, 这是因为推电子基团使苯环电子云密度提高, 有利于羟基自由基的进攻; 吸电子基团使苯环电子云密度降低, 不利于羟基自由基的进攻. 由于阴极还原反应的作用, 化学反应活性和电化学反应活性并不完全一致. 氯代苯胺在羟基自由基进攻下—Cl离去, 以Cl-离子形式进入溶液中, 被氧化生成有效氯, 加快降解反应速度. 硝基虽然是强吸电子基, 但是可以转化为对苯二胺, 进一步活化苯环, 其降解速度较快.     

Mannich反应合成3,6(8)-二取代-2,4-二氢-1,3-苯并噁嗪及其杀菌活性

以取代苯酚、多聚甲醛和取代苯胺为原料,在无催化剂的条件下,通过Mannich缩合反应合成了一系列新型3,6(8)-二取代-2,4-二氢-1,3-苯并噁嗪类化合物。 结果表明,取代苯酚和取代苯胺的取代基为供电子基时,合成产物的产率高于吸电子取代基的。 产物的结构用1H NMR、13C NMR、IR和MS等进行了表征。 初步测试了目标化合物的杀菌活性,部分化合物具有较好的杀菌活性。 当浓度为25 mg/L时,化合物4j和4d对菌核病菌的抑制率分别为86.1％和81.5％,化合物4i对灰霉病菌的抑制率为81.6％。     

二氧化钛悬浆体系中八种染料的太阳光催化氧化降解

研究了二氧化钛悬浆体系中具有不同结构和不同取代基的八种染料化合物在太阳光作用下的降解过程。实验中测定了染料溶液的脱色速度、总有机碳去除率以及降解过程中部分无机离子的生成情况。结果显示,在此条件下,八种染料化合物均得到不同程度的降解。着重比较了染料分子在光催化降解过程中,不同取代基以及取代基的不同位置对染料分子降解及无机离子生成情况的影响,从而进一步揭示了染料分子的光催化降解机理。     

掺硼金刚石电极电催化氧化酚类有机物的取代基效应

本文主要以当前水环境中存在酚类有机污染物为研究对象,探讨酚类有机污染物在掺硼金刚石(BDD)电极上的取代基效应,具体研究具有不同位置及种类官能团的取代酚类有机污染物在BDD电极上的电催化氧化过程,通过化学需氧量和浓度变化考察有机污染物在电催化降解过程中的降解趋势,深入分析电极种类、官能团位置与种类与电催化氧化活性之间的联系的同时,研究阳极材料电催化氧化有机污染物的机理及动力学。结果表明,有机物在电极表面的电催化过程以电产生羟基自由基为媒介,对苯二酚在不同电极上的电催化活性与电极析氧电位及表面产生羟基自由基量有着重要的联系,BDD电极拥有最强的电催化氧化活性;不同取代基团的对位取代酚在BDD电极上的电化学降解实验显示电催化反应速率受取代官能团自身的电子效应制约,有机物矿化过程中羟基自由基首先进攻苯环的对位发生取代反应,同时取代基脱离苯环过程成为整个取代酚类电化学降解过程的决速步骤,且有机物的电催化反应速率与取代基特征Hammett常数σ呈近似线性关系。     

硝基芳烃对圆腹雅罗鱼毒性的DFT研究

对30种硝基芳烃化合物进行DFT-B3LYP/6-311G**水平全优化计算, 据所得量子化学参数分类建立了硝基苯类和硝基苯胺类化合物对圆腹雅罗鱼急性毒性(－lgEC₅₀)的定量构效关系(QSARs)模型. 结果表明, 硝基苯类化合物的毒性主要由硝基基团的电荷(Q_-NO2)和前线轨道能级差(ΔE)决定; 硝基苯胺类化合物的毒性则由分子最低未占轨道能级(E_LUMO)和ΔE决定. 苯环上取代基的类型、数目和取代位置直接影响到标题化合物的毒性大小, 强吸电子基如硝基会降低Q_-NO2和E_LUMO大小, 使化合物毒性增强, 且邻对位硝基取代的毒性高于间位取代; 相反, 给电子基团氨基的存在则会使化合物的毒性降低. 总之, 硝基是这两类化合物致毒的主要基团, 将硝基包覆或还原为氨基应为此类化合物解毒的重要途径. 最后以1,4-二硝基苯为例, 模拟了其活性亚硝基中间产物与蛋白质中还原性巯基间的反应, 并将其与硝基苯和1,3-硝基苯的反应活化能进行了比较, 讨论了不同取代基数目和位置对分子活性的影响, 结果与QSAR模型分析一致, 进一步验证了硝基芳烃化合物的致毒历程, 研究结果对品优高能炸药的分子设计也有助益.     

1,3-偶极环加成反应合成1-(取代苄基)-1,2,3-三唑类化合物

利用苄氯和取代苄氯与叠氮化钠的亲核取代反应合成了一系列苯环上带有不同取代基团的苄基叠氮化合物,亲核取代反应速率受苯环上取代基的影响:吸电子基团的存在,可以促使反应更容易进行.合成的叠氮化合物与苯乙炔经1,3-偶极环加成反应得到了相应的取代苄基1,2,3-三唑类化合物,反应条件温和.这些1,2,3-三唑类目标化合物具有对热稳定的优点.用红外、核磁、元素分析、质谱等对合成的叠氮化合物和1,2,3-三唑类化合物的结构进行了表征,重点研究了1,3-环加成反应的规律.加成反应速率取决于叠氮化合物(偶极物)的极性,即与取代基的电负性有关:苯乙炔(亲偶极物)易于与缺电子的叠氮反应,反之亦然.同时在反应过程中观察到空间位阻效应:反应可以生成两种同分异构体,其中4-苯基-1,2,3-三唑是主要产物.     

N-(4,6-二甲氧基嘧啶-2-基)-N'-磷酰基脲类衍生物的合成及生物活性

利用二氯代磷酰基异氰酸酯与4,6-二甲氧基-2-氨基嘧啶的加成反应合成了中间体N-(4,6-二甲氧基嘧啶-2-基)-N'-二氯代磷酰基脲(Ⅰ).Ⅰ与2倍的醇或胺反应得到对称双取代磷酰基脲类化合物Ⅱa_Ⅱi;Ⅰ与1倍的胺反应得到氯代磷酰基脲类化合物Ⅲa_Ⅲe,再与1倍的醇反应则得到不对称双取代磷酰基脲类化合物Ⅳa_Ⅳg.生物活性测定结果表明,化合物Ⅱ、Ⅲ和Ⅳ均显示一定除草活性.     

邻氨基二苯醚类重氮盐的水解及分子内缩合反应

用邻氨基二苯醚类化合物进行重氮化水解反应制备邻羟基二苯醚类化合物, 对影响氯代邻氨基二苯醚重氮盐水解反应和分子内关环反应的因素进行了系统研究, 讨论了取代基、金属及其离子催化等对两类反应的影响规律, 揭示了在金属离子催化下, 邻氨基二苯醚类化合物重氮盐发生分子内关环反应的规律, 并推测了反应机理.     

具有生物活性的有机硅化合物研究(Ⅺ)——2-(三甲硅基)乙基硫代(N-取代)乙酰胺的研究

研究了2-(三甲硅基)乙基硫代乙酸与(取代)苯胺和脂肪胺直接缩合反应或在五氧化二磷存在下的反应,发现前者收率高于后者。由此合成了17种结构新颖的2-(三甲硅基)乙基硫代(N-取代)乙酰胺类化合物。通过NMR(¹H,¹³C)、IR和MS的研究,确定了这类化合物的结构,并探讨了化合物结构与波谱的关系。经测定,这些化合物的生物活性不甚理想。     

THE INVESTIGATION OF NUCLEOPHYLIC SUBSTITUTION IN DIPHENYLSULFONE SERIES

Abstract

The reactions of nucleophylic substitution of chlorine atoms in chlorine-substituted diphenylsulfones for oxy-, phenoxy-, sul-fo-, tiol and other groups were taken as the basis for numerous syntheses of organic sulfur compounds possessing practical importance. The kinetic investigations of chlorine atom substitution for oxy- and phenoxy- groups in 4,4′- dichlorodiphenylsulfone and 3,4′,3,4′ - tetrachlorodiphenylsulfone were carried out in detail. The effect of solvents on reaction rate was investigated. The possibility of only one chlorine atom selective substitution for some other functional groups in the compounds mentioned was described and the conditions for the same were found out.     

TiO2- and BaTiO3-assisted photocatalytic degradation of selected chloroorganic compounds in aqueous medium: correlation of reactivity/orientation effects of substituent groups of the pollutant molecule on the degradation rate

Investigation of the photocatalytic activity of BaTiO(3), a perovskite wideband gap semiconductor has been done in comparison with a widely used photocatalyst TiO(2) for the degradation of 4-chlorophenol (4-CP), 4-chloroaniline (4-CA), 3,4-dichloronitrobenzene (3,4-DCNB), and 2,4,5-trichlorophenol (2,4,5-TCP). BaTiO(3)/TiO(2) nanoparticles were prepared by gel-to-crystalline conversion method. BaTiO(3) has exhibited better catalytic efficiency and process efficiency compared with TiO(2) in most of the cases. The present research focuses mainly on two aspects: first the photocatalytic activity of BaTiO(3), as there are very few reports in the literature, and second the reactivity/orientation effects of substituent groups of the pollutant molecules on the degradation rate. The above chloroorganic compounds have at least one chlorine substituent in common, along with other functional groups such as -OH, -NH(2), and -NO(2). Furthermore, the effect of electron acceptors and pH on the rate of degradation is presented. The reactions follow first-order kinetics. The degradation reaction was followed by UV-vis, IR, and GC-MS spectroscopic techniques. On the basis of the identification of the intermediates, a probable degradation reaction mechanism has been proposed for each compound.     

Analytical monitoring of photocatalytic treatments. Degradation of 2,3,6-trichlorobenzoic acid in aqueous TiO(2) dispersions

The photocatalytic degradation of 2,3,6-trichlorobenzoic acid (2,3,6-TBA) in aqueous TiO(2) dispersions irradiated with simulated solar light was investigated. Fast primary degradation of the herbicide, which obeys a pseudo-first order law, was observed. Complete mineralisation of the organic carbon to CO(2) was obtained after long term irradiation, with corresponding stoichiometric transformation of organic chlorine into chloride ion. Various aromatic intermediates, originating from 2,3,6-TBA, were detected during the treatment and identified using GC-MS. From the analytical data, a possible multi-step degradation scheme was proposed. The photocatalytic treatment of the pesticide was also performed in the presence of Brij 35 micellar solutions, although strong inhibition of the process was observed. When surfactant aggregates are present the photocatalytic destruction of 2,3,6-TBA is still possible at reasonable rates only after a proper dilution of the waste and by increasing significantly the semiconductor/pollutant ratio.     

三氯乙烯预处理的TiO2薄膜上挥发性有机物的光催化反应

 制备了TiO2薄膜催化剂,并用三氯乙烯对其进行了预处理; 采用FT-IR,GC/MS及XPS等技术研究了三氯乙烯预处理的TiO2薄膜上挥发性有机物的光催化反应. 结果表明,三氯乙烯预处理能加快某些挥发性有机物的光催化反应. 这是由于氯作为三氯乙烯气相光催化分解反应的中间产物吸附在催化剂表面,成为反应的活性物种引发挥发性有机物发生游离基反应,从而提高其气相光催化反应速率.     

Modification of poly(epichlorohydrin) with nadimide derivatives and their curing reaction

Chemical modification of poly(epichlorohydrin) (PECH) with nadimide derivatives using 1,8-diazabicyclo (5.4.0)?7 undecene to catalyze the substitution of the chlorine atom by acid compounds (DBU method) was accomplished. The linear polyethers obtained showed a degree of substitution from 5–80%, depending on time and temperature reaction. The T_g of modified polymers and Ea, calculated in the cure reactions, increases with substitution degree. Residual enthalpies were observed in all cases, which suggests that the curing reaction is incomplete. TGA measurements showed that the degradation has a greater dependence on the modification degree than on the introduced pendant group. © 1994 John Wiley & Sons, Inc.     

Degradation and isomerization of 1,2-dichloroethenes by photocatalytic reactions

The photocatalytic degradation and isomerization of trans- and cis-1,2-dichloroethenes (1,2-DCEs) by TiO₂ photocatalyst have been investigated using gas chromatography. The reaction half-life of 1,2-DCEs in nitrogen was longer than in dry air and oxygen, and the initial concentration of them affects the extent of the isomerization. The results indicate that the oxygen molecule and chlorine atoms play an important role in the degradation and isomerization of 1,2-DCE. It is also apparent that the photocatalytic degradation of 1,2-DCEs occurs on the TiO₂ surface.     

Electron capture negative ion and positive ion chemical ionization mass spectrometry of polychlorinated phenoxyanisoles

Several polychlorinated phenoxyphenols with three to nine chlorine atoms were examined as their methyl ethers by electron capture negative ion and positive ion chemical ionization and electron impact mass spectrometry. In chemical ionization studies methane, hydrogen, nitrogen, helium and argon were used as reagent gases. Selected compounds were also examined with deuteriomethane, ammonia and deuterioammonia as reagent gases. Utilization of chemical ionization spectra in conjuction with electron impact spectra provides substantial structural information about these compounds. Chemical ionization spectra provide information about chlorine atom substitution. The position of phenoxy substitution can be established from electron capture negative ion and positive ion spectra.     

空气中苯系物的TiO2光催化降解研究进展

本文对近年来空气中挥发性苯系物的TiO2光催化降解机理、TiO2光催化降解苯系物的主要影响因素以及TiO2的失活与再生方法等的研究进展进行了较详尽的评述,并对今后的研究工作进行了展望。     

Study of some UV filters stability in chlorinated water and identification of halogenated by-products by gas chromatography-mass spectrometry

This work studies the stability of three UV filters: 2-ethylhexyl salicylate (ES), 2-ethylhexyl 4-(dimethylamino) benzoate (EHPABA) and 2-hydroxy-4-methoxybenzophenone (BP-3), in water samples containing low concentrations of free chlorine. Moreover, 2,4-dihydroxybenzophenone (2,4-DHBP), a metabolite of BP-3, was also included in some of the performed assays. Experiments were carried out considering free chlorine and analytes concentrations at the microg mL(-1) and ng mL(-1) level, respectively. Gas chromatography with mass spectrometry was used to follow the time course of target compounds and to identify their halogenated by-products. Concentration of water samples with solid-phase extraction cartridges and derivatization (silylation) of some species were also employed to improve their detectability. Under the experimental conditions explored in this work, ES showed an acceptable stability whereas the rest of species reacted with free chlorine at significant rates following pseudo-first-order kinetics. Their half-lives ranged from 0.4 to 25 min depending on the UV filter, chlorine concentration, water pH and presence of bromide traces. For EHPABA a relatively simple degradation pathway was established. It consisted of aromatic substitution of one atom of hydrogen per chlorine or bromide. The same reaction pattern was observed for BP-3 leading, in this case, to mono- and di-halogenated by-products. In addition, several halogenated forms of 3-methoxyphenol were identified as BP-3 cleavage by-products.     

Liquid chromatography/time-of-flight mass spectrometric analyses for the elucidation of the photodegradation products of triclosan in wastewater samples

Liquid chromatography coupled with time-of-flight mass spectrometry (LC/TOFMS) was applied for the identification of four new photodegradation products of triclosan, a major antimicrobial agent used in personal care products. Wastewater samples, spiked at 7 microg/mL with triclosan, were irradiated with natural sunlight in order to generate the photodegradation products. Aliquots of the spiked water samples were taken at different times of irradiation and compounds were isolated from the water samples by solid-phase extraction. Separation and detection of the compounds and degradation products were accomplished by LC/TOFMS, which provided highly selective information about elemental compositions. Accurate mass measurements for the four degradation products permitted postulation of proposed empirical formulae in this study. Replacement of chlorine atoms by hydroxyl groups and chlorine losses are the major degradation pathways proposed. The degradation products were formed also under environmental conditions in wastewater matrices, thus suggesting their presence in real wastewater treatment processes.