荧光法研究对-二甲氨甲基-杯[8]芳烃与二苯胺磺酸钠包结作用

用荧光法研究了水溶性对-二甲氨甲基-杯[8]芳烃与二苯胺磺酸钠的相互作用。发现当对-二甲氨甲基-杯[8]芳烃加入到二苯胺磺酸钠溶液时,二苯胺磺酸钠的荧光峰发生了明显的蓝移,荧光增强,可能的作用机理是二苯胺磺酸钠中的磺酸根与对-二甲氨甲基-杯[8]芳烃中带正电的氮原子之间有较强的静电作用,二苯胺磺酸钠进入了对-二甲氨甲基-杯[8]芳烃的疏水空腔。同时研究了几种有机溶剂对包结物的荧光强度的影响,初步探讨了其作用机理。     

Dawson结构磷钨钒杂多酸有机铵盐的合成及光谱研究

以偏钒酸铵、磷酸二氢钠和钨酸钠为原料,调节溶液的pH值为4,控制反应时间为10 h,合成了三钒取代的Dawson结构磷钨钒杂多酸,然后以化学反应计量的5倍量加入抗衡离子K+,制备了母体杂多酸盐K9P2W15V3O62·41H2O。在不断的搅拌下,将母体杂多酸盐的酸性溶液缓慢滴加到十六烷基三甲基溴化铵溶液中,合成了目标化合物磷钨钒杂多酸有机铵盐(C19H42N)6H3[P2W15V3O62]。经元素分析、红外光谱、X射线粉末衍射、差热-热重等手段进行了表征,表明目标化合物仍保持Dawson结构,为未见文献报道的杂多化合物。     

PMR Spectrometric Analysis of Tolmetin Sodium in Capsules Forms

An analytical method is described for the assay of tolmetin, 1-methyl-5-(4-methylbenzoyl)-1H-pyrrole-2-acetic acid, as sodium salt, (Tolectin[rgrave] - 200 mg) using PMR. The protocol reported in this study is simple, precise and yields accurate results of 99.78±0.84 and 100.67±2.08 for the authentic material and capsules respectively. In addition, the PMR spectrum obtained provides a means for qualitative identification of the drug and checking its purity. The principle of the method involves comparison of the integral of the well-defined singlet (positioned at 2.41 Δ) to that of the sharp singlet due -CH₃ (positioned at 1.91 Δ) of sodium acetate as an internal standard in presence of maleic acid using DMSO-d₆ solvent. The rationale for the use of maleic acid in the assay procedure has been discussed.     

磺胺-N-苯基J酸分光光度法测定亚硝酸盐研究

筛选了重氮组分和偶合组分。研究了重氮偶合显色反应的条件和方法,提出了借助于磺胺-J酸系列染料中间体(N-苯基J酸、J酸、双J酸)重氮偶合技术分光光度法测定亚硝酸盐。在常温溴化钾共存下,亚硝酸盐在稀盐酸溶液中与磺胺发生重氮化反应,在碳酸钠水溶液中重氮盐与J酸系列染料中间体偶合生成有色偶氮化合物。磺胺-N-苯基J酸偶氮化合物的表观摩尔吸光系数为4.63×104 L·mol-1·cm-1,线性范围为0.003～0.7 mg·L-1,回收率为99.5%～101.6%。相对标准偏差为2.10%。该本方法可用于环境水体中痕量亚硝酸盐的测定。     

超声波作用下乙酸辛酯合成条件的研究

在超声波作用下,不用溶剂,以硫酸氢钠为催化剂催化合成乙酸辛酯。最佳反应条件是:正辛醇和乙酸的物质的量比为1∶2.0,催化剂用量为反应物总质量的1.0%,超声时间20min,反应温度84℃。在此反应条件下,酯收率可达80.1%,催化剂可重复使用。     

J酸分光光度法测定芳香族氨基化合物

综合考虑显色反应选择性、反应速度、灵敏度和偶氮化合物的水溶性等问题,通过对偶合组分分子结构的理论设计和实验筛选,研究了显色反应方法和条件,提出利用J酸(2-氨基-5-萘酚-7-磺酸)作为偶合试剂分光光度法测定水中芳香族氨基化合物。溴化钾催化,室温下,亚硝酸盐与芳香族氨基化合物在稀盐酸水溶液中发生重氮化反应,在碳酸钠水溶液中重氮盐与J酸偶合生成有色偶氮化合物,最大吸收波长480 nm。所测苯胺、4-氨基苯磺酸和1-萘胺的表观摩尔吸光系数分别为3.95×104,3.24×104和3.91×104 L·mol-1·cm-1。水中共存离子影响研究结果表明: 地表水中常见离子对测定结果不产生影响。采用J酸分光光度法测定了上海市复兴岛运河水样,同时,用标准加入法做回收实验,实验结果：苯胺回收率为98.5%～102.1%,相对标准偏差2.08%。J酸是一种常见有机试剂,易溶于水,挥发性低,其毒性大大低于盐酸萘乙二胺。J酸分光光度法测定芳香族氨基化合物具有灵敏度高、选择性好、操作简单快速、测定结果准确等优点,可用于环境水体中痕量芳香族氨基化合物的测定。     

Pseudo‐homogeneous kinetic model for esterification of acetic acid with propanol isomers over dodecatungstophosphoric acid supported on montmorillonite k10

Esterification of acetic acid with propanol isomers such as isopropanol and n‐propanol was carried out over dodecatungstophosphoric acid (DTPA), dodecamolybdophosphoric acid ammonium salt hydrate, and sodium tungstate hydrated purified supported on montmorillonite K10, which were characterized by powder X‐ray diffraction, Brunauer–Emmett–Teller, and temperature programmed ammonia desorption. A pseudo‐homogeneous (P‐H) kinetic model was established for esterification of acetic acid with propanol isomers over DTPA supported on montmorillonite K10. Effects of various parameters such as reaction time, speed of agitation, particle size, temperature, percent catalyst loading, molar ratio and mixture of propanol isomer were investigated in detail. The 20% (w/w) DTPA/K10 was found to be an optimum solid catalyst with 82% n‐propanol and 53% isopropanol conversion with 100% selectivity toward propyl acetate. The 20% (w/w) DTPA/K10 catalyst was found to be reusable for three cycles. The reaction follows second‐order kinetics with activation energies of 25.53 kJ mol^?1 and 28.15 kJ mol^?1 for isopropanol and n‐propanol, respectively. Pseudo‐homogeneous kinetic model fitted with R² value of trend line 0.999. This implies that esterification reaction is kinetically controlled owing to high activation energy. Copyright © 2013 John Wiley & Sons, Ltd.     

Solvent-free sonochemical preparation of α-aminophosphonates catalyzed by 1-hexanesulphonic acid sodium salt

1-Hexanesulphonic acid sodium salt was found to be an efficient catalyst for the green synthesis of α-aminophosphonates by the coupling of aldehydes/ketone, an amine and triethyl phosphite under ultrasound irradiation at ambient temperature for appropriate time to furnish the desired product in good to excellent yield under solvent-free condition. This catalyst provides clean conversion; greater selectivity and easy workup make this protocol practical and economically attractive.     

23Na and (1)H NMR microimaging of intact plants

(23)Na NMR microimaging is described to map, for the first time, the sodium distribution in living plants. As an example, the response of 6-day-old seedlings of Ricinus communis to exposure to sodium chloride concentrations from 5 to 300 mM was observed in vivo using (23)Na as well as (1)H NMR microimaging. Experiments were performed at 11.75 T with a double resonant (23)Na-(1)H probehead. The probehead was homebuilt and equipped with a climate chamber. T(1) and T(2) of (23)Na were measured in the cross section of the hypocotyl. Within 85 min (23)Na images with an in-plane resolution of 156 x 156 micrometer were acquired. With this spatial information, the different types of tissue in the hypocotyl can be discerned. The measurement time appears to be short compared to the time scale of sodium uptake and accumulation in the plant so that the kinetics of salt stress can be followed. In conclusion, (23)Na NMR microimaging promises great potential for physiological studies of the consequences of salt stress on the macroscopic level and thus may become a unique tool for characterizing plants with respect to salt tolerance and salt sensitivity.     

动力学分光光度法测定食用碘盐中碘酸根

在存在氯化钠的硫酸介质中,碘酸根与碘离子反应生成中间体三碘离子,进而与淀粉反应生成蓝色络合物,据此,提出了动力学分光光度测定碘酸根的新方法。反应体系的3个特征峰 (291, 354和585 nm) 被用来优化实验条件。当反应时间为180 s时,在最佳的实验条件下,碘酸根在这3个特征峰下的线性范围分别为0.1～1.2,0.05～1.2和0.1～1.2 μg·mL-1, 检测限分别为0.047,0.027和0.048 μg·mL-1。实验发现354 nm处测定的线性范围较宽且检测限最低,该波长可被用于定量分析。该方法应用于食用碘盐中的碘酸根测定。     

1,2-Naphthoquinone-4-Sulphonic Acid Sodium Salt (NQS) as an Analytical Reagent for the Determination of Pharmaceutical Amine by Spectrophotometry

Abstract: Several papers have been presented in recent years regarding the field of application of 1,2-naphthoquinone-4-sulphonic acid sodium salt (NQS) as a chromogenic reagent for the determination of pharmaceutical amines using spectrophotometry. In this review article, various spectrophotometric methods using NQS as a labeling reagent for determination of pharmaceutical amines are presented. The application of these methods for the determination of drugs in pharmaceutical formulations and real samples is discussed.     

Use of sodium beta alumina in novel processes for the production of metals

Sodium metal is an excellent reductant and can be used to reduce most metallic chlorides and many oxides. However, sodium is relatively expensive and is hazardous to store so that it is only used to reduce titanium tetrachloride to titanium. In-situ electrolytic preparation of sodium from sodium chloride in a reactor is difficult due to the evolution of chlorine, another hazardous substance. A novel cell is described where the sodium salt is separated from the salt to be reduced by a sodium beta alumina membrane. The anode is in the sodium salt and the cathode is in the metallic salt and, on the application of current, it has been found that the metal ions are reduced to the metal and the anion in the sodium salt is oxidised. By using sodium hydroxide or sodium carbonate as the sodium salt, the anodic products are oxygen and water vapour or oxygen and carbon dioxide. Examples are given of electrolytic cells incorporating beta alumina membranes for the production of magnesium and zirconium from the chlorides where the metal is produced and the anodic gases are not toxic. Overall these cells are very efficient as the anodic and cathodic products are separated by the beta alumina membrane and compared with existing cells some of the electrical energy requirement is replaced by chemical energy. The environmental benefits of these cells are very attractive for the production of reactive metals on a small scale. Paper presented at the 4th Euroconference on Solid State Ionics, Connemara, Galway, Ireland, Sept. 13–19, 1997     

A new simple synthesis of CdS nano-particles by composite-molten-salt method and their high photocatalytic degradation activity

Nano-CdS crystal has been succesfully synthesized by composite molten salt (CMS) method for the first time, using composite molten salt as a reaction solvent, sodium sulfide and cadmium nitrate hexahydrate as reactants at temperature of 200 °C for 24 h in the absence of organic dispersant or capping agents. X-ray diffraction and field emission scanning electron microscopy (FESEM) images indicated that the as-synthesized product were well crystallized and belonged to nano-scale. Their UV–vis absorption spectrum demonstrated a band gap of 2.49 eV corresponding to the absorption edge of 499 nm. The experimental result of photocatalytic degradation on methyl orange by the nano-CdS showed much better photocatalysis than that by the commercial CdS powder under the irradiation of ultraviolet light source.     

Convenient Synthesis 1H, 13C NMR Study and X-Ray Crystal Structure Determination of Some New Disubstituted Thiophenes

2,5-, 3,4- and 2,3-Thienylenediacrylic (1, 4 and 7 respectively) were synthesized in one step reaction by catalytic vinylation of the corresponding dibromothiophenes in the presence of cyclohexylamine salt of acrylic acid. 2,4-Thienylenediacrylic acid 10 was prepared by catalytic vinylation of 3-(4-bromo-2-thienyl)acryilic acid.     

分光光度法研究改性沸石对Fe2+的吸附性能

采用微波辐射技术结合酸、碱、盐分别对沸石进行活化改性处理,用分光光度法分析改性沸石对Fe2+的吸附性能及影响因素。结果表明:NaOH改性沸石对Fe2+的去除效果优于NaCl、HCl改性沸石,当微波功率为640W,微波时间为5min,NaOH浓度为0.8mol/L时,Fe2+去除率可达98.56%。经过对改性沸石再生,NaOH浸泡过的改性沸石再生性较好。     

One-pot synthesis of 1,2,3-triazole linked dihydropyrimidinones via Huisgen 1,3-dipolar/Biginelli cycloaddition

The combination of the Biginelli reaction with click chemistry has been used for the one-pot synthesis of 1,2,3-triazole linked dihydropyrimidinones from azides, aromatic aldehydes containing a propargyl ether group, urea, and 1,3-dicarbonyl compounds using Cu(OAc)₂/sodium ascorbate as catalyst in acetic acid under mild reaction conditions.     

Chromium Speciation Using Ion Chromatography-Atomic Absorption System with On-Line Preconcentration

A method using ion chromatography-atomic absorption system (IC-AA) with on-line preconcentration unit is developed for the speciation of chromium in aqueous samples. Both Cr(III) and Cr(VI) species are pre-treated with sodium salt of ethylenediaminetetraacetic acid (EDTA) in consecutive steps. The treated samples can then be injected into an on-line preconcentration unit followed by ion chromatographic separation with UV or selective flame AA detection. Both chromium species can be separated within 10 minutes, and the method is applicable for aqueous samples with ppm levels of chromium.     

反相离子对高效液相色谱法测定血浆中的溴新斯的明

建立了血浆中溴新斯的明的反相离子对高效液相色谱测定方法。血浆样品加沉淀剂苦味酸氢氧化钠溶液,旋涡离心,经四丁基氯化铵萃取后取上清液进样测定。色谱柱为lichrospher C18（4.6mm×250mm,5μm）;流动相为庚烷磺酸钠溶液（0.01mol/L,磷酸二氢钠0.013mol/L,用磷酸调节pH 3.0）∶乙腈=77∶23,V/V;紫外检测波长260nm;流速1.0mL/min;柱温为30℃。血浆中溴新斯的明的检出限为0.005mg/L,定量下限为0.01mg/L。血浆中溴新斯的明的线性范围为0.05—10.0mg/L,r=0.9991。本方法准确、专属性强,适用于血浆中溴新斯的明的浓度测定。     

A rationale on the role of intermediate Au(III)–vitamin C complexation in the production of gold nanoparticles

Preparation of gold nanoparticles, particularly gold nanorods, by wet chemistry processes involves gold seeds, an Au(III) salt, structure directing surfactants, and metal ion additives in the growth solution into which a weak reducing agent is added. The most commonly employed weak reducing agent is l-ascorbic acid (vitamin C) which is known to reduce many metal ions in the solution phase and form complexes with relatively low stability constants. A purple-gray gold–ascorbate compound, obtained from the reaction of sodium tetrachloroaurate(III) with sodium ascorbate, is now reported. The compound possesses the expected structural features of vitamin C–metal complexes as verified by its ¹³C CP-MAS NMR spectrum. A discussion is also presented on the possibility of gold–ascorbate complexation operating in gold nanoparticle formation.     

分光光度法测定日化品中的三氯生

建立了分光光度法测定日化品中三氯生的方法。在酸性条件下,亚硝酸钠和对氨基苯磺酸生成重氮盐,三氯生在碱性条件下与此重氮盐发生偶合反应,形成的黄色偶氮化合物,其在452nm处有最大吸收。三氯生浓度在0.075—30mg/L范围内呈良好的线性关系,检出限为0.075mg/L。本方法成功应用于日化产品中三氯生的测定,与高效液相色谱法相比,结果令人满意。