钝化芳环的硝化研究进展*

芳香族化合物的硝化反应是工业生产中重要的单元反应,钝化芳环的硝化反应在医药、农药、染料和炸药合成中有重要地位。本文从硝化试剂角度综述了近年来钝化芳环的硝化反应的进展,包括硝酸盐/硫酸、硝酸酯、硝酸、氮氧化物等硝化方法。简要评述了这些方法的特点,并展望了硝化方法的研究方向。其中,硝酸盐/硫酸体系具有较强的硝化能力,对于钝化芳环,可以在温和条件下以高收率得到硝化产物,在实验室制备或工业应用中具有较高的应用价值;其他硝化方法由于各种原因暂时不能对钝化程度较高的芳环进行硝化,还需进一步研究具有较高活性的硝化体系。     

Nitration of Some Aromatic Compounds by Sodium Nitrate in the Presence of Benzyltriphenylphosphonium Peroxodisulfate

A simple, mild, and regioselective method for the nitration of some aromatic compounds using sodium nitrate in the presence of benzyltriphenylphosphonium peroxodisulfate in acetonitrile as solvent is reported. Mild reaction conditions and good to excellent yields of the products are the noteworthy advantages of the method.     

Fast and Efficient Nitration of Salicylic Acid and Some Other Aromatic Compounds over H_3PO_4/TiO_2-ZrO_2 Using Nitric Acid

TiO₂‐ZrO₂ (1/1)‐surf with Ti and Zr molar ratio of 1/1 was prepared with surfactant through a sol‐gel method. The optimum experimental condition was investigated for nitration of salicylic acid. Then, a number of nitration reactions were carried out with a variety of aromatic compounds in the optimum condition. The 25 wt% H₃PO₄/TiO₂‐ZrO₂ (1/1)‐surf catalyst showed good selectivity and yield in a short time for the nitration of salicylic acid and some other aromatic compounds.     

Mild and Efficient Nitration of Aromatic Compounds Mediated by Transition-Metal Complexes

Aromatic compounds were efficiently nitrated under facile reaction conditions by employing 69% nitric acid catalyzed by transition-metal complexes such as [Co(NH₃)₅Cl]Cl₂, [Cu(NH₃)₄]SO₄, Mn(acac)₃, [Ni(NH₃)₆]Cl₂, [Ni(en)₃]S₂O₃, and Hg[Co(SCN)₄]. The reaction was completed smoothly at room temperature and afforded corresponding mono-nitro derivatives in quantitative yield. This new method offers efficient and facile regioselective mononitration of aromatic compounds.

A Mild and Efficient Route to 3-Vinylchromones in Aqueous Micellar Media

A simple, mild, and ecofriendly method has been developed for the synthesis of 3-vinylchromones from 4-oxo-4H-1-benzopyran-3-carboxaldehyde (3-formylchromone) by simple Knoevenagel condensation with various active methylene compounds (AMC) in aqueous micellar media in the presence of catalytic amounts of cetyl trimethylammonium bromide (CTAB) and 1,4-diazabicyclo[2.2.2]octane (DABCO). In the case of malonic acid as AMC, the reaction resulted in formation of only Doebner decarboxylated products under the standard reaction condition. It has been also observed that 3-formylchromone derivatives primarily undergo tandem Knoevenagel and Michael reactions in the presence of > 2 equiv. of ethyl acetoacetate to produce benzophenone derivatives, by opening of pyran ring, as the sole product in good yields.     

Nitration of Aromatic Hydrocarbons and Halobenzenes Using NOx Catalyzed by Solid Acid Catalysts

The nitration of aromatics using zeolite as a solid inorganic catalyst and nitric oxides as nitrating agents is a relatively clean process for aromatic nitration.     

用偏最小二乘法—荧光光谱法定量分析芳烃混合物

本文用偏最小二乘法方法来解析荧光的激发发射和左阵，直接定量分析荧光混合物试样。文中分析了ＥＥＭ的特点，介绍了用ＥＥＭ－ＰＬＳ定量分析试样的思路和方法，并对５个模拟混合物和４个实际混合物进行了测试和计算，获得了满意的结果。本文还用实例讨论了数据中的异常点，对结果的影响及晚年剔除的方法。     

香料成分的结构与高温裂解产生芳香物质含量的关系研究

应用在线热裂解/气相色谱-质谱(PY/GC-MS)研究了紫苏葶、β-紫罗兰酮、香紫苏内酯、异丁香酚、苯甲醛、2-乙酰基吡嗪、2-乙酰基噻唑、3-乙酰基吡啶、山楂酊、树兰净油在氦气氛围中分别于300、600、800℃下的裂解产物,通过对裂解产物中芳香烃类化合物的分析,讨论了裂解温度和香料组分化学结构对芳香族物质产生量的影响,并以有机结构理论总结了香料成分的结构与高温裂解产生芳烃物质含量的关系。研究结果表明:β-紫罗兰酮、香紫苏内酯、异丁香酚、树兰净油等在800℃时均裂解生成芳香烃类化合物(苯系物、茚系物和萘系物),其中裂解物中芳香烃类物质含量最高者为β-紫罗兰酮,达到16.290%,树兰净油为5.376%;而2-乙酰基吡嗪、2-乙酰基噻唑、3-乙酰基吡啶的裂解产物中未检测到上述芳香烃类物质,香料成分的结构是高温裂解产生芳烃物质的重要因素;随着裂解温度的升高,裂解产物中芳香烃类化合物的含量呈上升趋势;其中2-乙酰基吡嗪、2-乙酰基噻唑和3-乙酰基吡啶适宜用作卷烟香料。     

Sensitive Synchronous Spectrofluorimetric Methods for the Determination of 1- and 2-Naphthol in Micellar Media

Abstract

The interaction of 1-naphthol and 2-naphthol with several quaternary ammonium salts was studied. Spectrofluorimetric methods were developed for the determination of both naphthols in hexadecyltrimethylammonium bromide micellar medium. The detection limits are 1.4 and 10.2 ng/ml for 1-naphthol, and 6.2 and 5.1 ng/ml for 2-naphthol employing the conventional and synchronous spectrofluorimetric methods, respectively. The use of the first-derivative spectrum allows for the simultaneous determination of both naphthols. The recoveries of 1-naphthol and 2-naphthol in natural waters are acceptable.     

Integrating a Luminescent Porous Aromatic Framework into Indicator Papers for Facile,Rapid, and Selective Detection of Nitro Compounds

Porous aromatic framework materials with high stability, sensitivity, and selectivity have great potential to provide new sensors for optoelectronic/fluorescent probe devices. In this work, a luminescent porous aromatic framework material (LNU-23) was synthesized via the palladium-catalyzed Suzuki cross-coupling reaction of tetrabromopyrene and 1,2-bisphenyldiborate pinacol ester. The resulting PAF solid exhibited strong fluorescence emission with a quantum yield of 18.31%, showing excellent light and heat stability. Because the lowest unoccupied molecular orbital (LUMO) of LNU-23 was higher than that of the nitro compounds, there was an energy transfer from the excited LNU-23 to the analyte, leading to the selective fluorescence quenching with a limit of detection (LOD) ≈ 1.47 × 10⁻⁵ M. After integrating the luminescent PAF powder on the paper by a simple dipping method, the indicator papers revealed a fast fluorescence response to gaseous nitrobenzene within 10 s, which shows great potential in outdoor fluorescence detection of nitro compounds.     

稀盐酸中锌粉促进的羰基化合物的Pian呐醇偶联

报道了2mol/L的盐酸水溶液中锌粉促进芳香族羰基化合物的Pian呐醇偶联。该 反应条件温和、操作简便、产率高。     

Determination of Guanidino Compounds in Serum by Micellar Electrokinetic Capillary Chromatography Using Benzoin as the Derivatizing Reagent

An analytical procedure has been evolved for the determination of seven guanidino compounds; guanidine (G), methylguanidine (MG), guanidinoacetic acid (GAA), guanidinopropionic acid (GPA), guanidinobutyric acid (GBA), arginine (Arg), and guanidinosuccinic acid (GSA) by micellar electrokinetic capillary chromatography (MEKC) within 6 min using benzoin as derivatizing reagent. Sodium dodecyl sulfate (SDS) was used as the micellar medium in a sodium tetraborate (0.1 M) buffer at pH 8.5. Uncoated fused silica capillary was used with an effective length of 39 cm and 75 μm id. Applied voltage was 25 kV and photo diode array detection was set at 228 nm. Linear calibrations obtained from 0.057 to 14.11 μmol/L and limits of detection (LOD) were within 0.019–0.03 μmol/L. The derivatization and separation was repeatable with relative standard deviation (RSD) within 1.9–3.8%. Serum of healthy volunteers and uremic patients was analyzed and amounts found in uremic patients were G 1.98–3.03, MG 1.21–1.79, GAA 3.67–6.09, GPA 1.17–1.37, GBA 1.29–1.46, Arg 9.49–19.17, and GSA 6.83–10.91 μmol/L with RSD (n = 4) within 1.3–4.5%. The amount of guanidino compounds was higher in uremic patients than in healthy volunteers.     

Development of the Headspace SPME/ATR‐IR Method for Detection of Chlorinated Aromatic Compounds in Soils

In this paper, a new method based on attenuated total reflection infrared (ATR‐IR) spectroscopy was developed to detect chlorinated aromatic compounds in soil. To eliminate the problems associated in inspection of soil samples by the ATR‐IR method, chlorinated compounds were evaporated from soil matrices and detected in the headspace. The sensing device was constructed by an internal reflection element (IRE) coated with a hydrophobic film to attract and concentrate chlorinated compounds evaporated to the headspace. Factors that influence the analytical signals were studied such as the moisture content, volatilities of analytes, and effect of heating temperature. Results indicated that the addition of thermal energy to the soil sample resulted in an increase of IR signal. However, the IRE was also warmed up and caused a slight decrease of the IR signals after a long detection time. The studies of the influence of moisture indicated that a small amount of water present in soils could tremendously increase the intensity of detected IR signals. The further increase of moisture contents resulted in a decrease of the analytical signals, and the optimal signal was found when soil samples contained 5% (v/w) water. Results in analyses of compounds with different volatilities indicated that even with vapor pressure lower than 0.017 Torrs, quality IR spectra could still be obtained. Using the optimal conditions found in this work, the results in determination of five compounds in soil samples indicated that the linear regression coefficients (R‐square) were higher than 0.992 with detection limits around a few hundreds of ppb.     

稳态荧光探针法测定临界胶束聚集数

以芘为荧光探针、二苯甲酮为猝灭剂,用稳态荧光探针法测定了SDS和AS的胶束聚集数(Nm).以芘的饱和水溶液为溶剂配制表面活性剂溶液,二苯甲酮的适宜浓度取小于1.00 mmol•L－1时,可以获得满意的实验结果.当表面活性剂溶液浓度为5～9倍cmc时,Nm随表面活性剂浓度增大而线性增大,而随温度的变化略有波动.cSAA=cmc时,Nm值为一本征值,定义为临界胶束聚集数[Nm].[Nm]值可从Nm－cSAA实验曲线外延得到.25℃时SDS的临界胶束聚集数[Nm]为57;40℃时SDS的[Nm]为49,AS的[Nm]为55.     

Correlation of Quantitative Structure and Inhibition Phytotoxicity for Aromatic Compounds Using Ab Initio Method

1 INTRODUCTION Quantitative structure-activity relationship (QSAR) is one of the necessary methods to evaluate the ha- zards of organic chemicals. QSAR equation could be employed to forecast the biological activity of un- known compounds, which is significant for initial screening and evaluation of toxic compounds[1]. Aro- matic compounds are toxic organic compounds with relatively low water solubility, and their structure- activity relationship has been investigated with AM1 method[2]…     

硅胶硫酸催化肟转化为羰基化合物的有效方法

在硅胶硫酸催化和十二烷基磺酸钠存在下,肟与多聚甲醛在90℃的水溶液中搅拌反应15～120 min生成相应的羰基化合物,收率68%～98%.     

A Practical Iodination of Aromatic Compounds by Using Iodine and Iodic Acid

This article describes simple and efficient method for the iodination of different aromatic amines, hydroxy aromatic aldehydes, hydroxy acetophenones and phenols using iodine and iodic acid in ethanol as a solvent. Notable advantages include mild reaction condition, no need of catalyst, short reaction time, simple practical procedure, giving excellent yield of the product.     

Highly Efficient Dinitration of Aromatic Compounds in Fluorous Media using Ytterbium Perfluorooctanesulfonate and Perfluorooctanesulfonic Acid as Catalysts

Ytterbium perfluorooctanesulfonate [Yb(OPf)₃] and perfluorooctanesulfonic acid [PfOH] catalyze the highly efficient dinitration of toluene, benzene, benzyl chloride, and chlorobenzene in fluorous media. Notably the process produces almost no waste acid, as opposed to the traditional case. The fluorous phase‐containing catalyst could be easily and efficiently recovered for reuse by simple phase separation.     

胶束电动毛细管色谱法测定地层水中的单环芳烃

二甲苯;环境分析;胶束电动毛细管色谱法测定地层水中的单环芳烃