微波辐射下双(2-苯并咪唑基)丙烷的合成与结构表征

与传统加热相比较,微波辐射促进的有机合成反应具有加热时间短、节能、产率高、不使用或少使用溶剂而对环境友好和节约成本等优点[1]。苯并咪唑类化合物具有广泛的生物活性而被应用到仿生有机合成、遗传学染色体研究及单层膜合成与形态研究的领域[2～4]。苯并咪唑类化合物的传统合成方法是:在HC1、多聚磷酸(PPA)、H3BO3等酸性催化剂使用下加热回流有机酸与邻苯二胺的混合物,然而反应通常需要较高的压力、温度或较长的时间,副反应多[5]。本研究在微波辐射下,以戊二酸和邻苯二胺为原料、PPA为催化剂合成了双(2-苯并咪唑基)丙烷,用正交试…     

废弃线路板化学分析采样、制样及检测方法

介绍废弃线路板中有回收价值元素和有害物质分析的采样、制样及检测技术。样品经过分类采样、剪切破碎和高温灰化制样,采用样品全分析或副批混合样分析。通过提高称样量、多次测定求平均值的办法,火试金富集-重量法测定贵金属金、银。湿法王水溶解样品,碘量法测定主体元素铜。电感耦合等离子体发射光谱(ICP-AES)法测定其它杂质元素,被测元素质量浓度在0~10μg/mL范围内与光谱强度呈良好线性关系,相关系数均大于0.9998。测定结果的相对标准偏差小于10%(n=5),加标回收率为97.0%~102.5%。该方法简单、快速,有效地解决了线路板样品不均匀而难采样,以及硬度、韧性强制样难,金属易包裹难分解的技术瓶颈,测定结果准确,具有代表性。该方法适用于废弃线路板化学成分分析,其它废弃电子产品检测可参考此方法。     

呋喃西林水溶液在光和热作用下的稳定性

The influence of both light and heat on the stability of nitrofurazone aqueous solution was studied. Results show that in either heating experiments or the exposure to light at high temperatures, the degradation rate obeyed zero-order kinetics. The total rate constant ktotal caused by both light and heat can be divided into two parts: ktotal =kdark klight, where kdark and klight are the degradation rate constants caused by heat and light, respectively. The klight can be expressed as klight=Alight*exp(-Ea,light/RT)*E, where E is the illuminance of light, and Alight and Ea,light both are experimental constants. The values of these kinetic parameters were determined based on the experiments in the dark and upon exposure to three different light sources. Results show that the values of Alight and Ea, light varied with the light source. To save time, labor, and drugs, exponential heating experiments were employed and compared with the isothermal experiments. Results indicated that kinetic parameters obtained by exponential heating experiments are comparable to those obtained by isothermal experiments either in the dark or upon exposure to light.     

Novel method for bulk resistance evaluation in conductivity measurement for high-purity water

A major issue with the electrolytic conductivity measurement for pure water is the lack of standard or reference methods. A primary method traceable to SI and suitable for pure-water conductivity measurement was developed at the Physikalisch-Technische Bundesanstalt (PTB), Germany, as the base for the calibration method for the conductivity measuring devices at the low conductivity level. This paper provides a novel method to calculate the bulk resistance of pure water using impedance measured at a single frequency, which is one of the key procedures for the primary methods.     

综合创新型实验:乙胺嘧啶合成的设计与教学实践

乙胺嘧啶(商品名:达拉匹林)是一种抗寄生虫药物,改进了合成方法,并设计转化为创新型综合教学实验。从对氯苯乙腈出发,使用丙酸乙酯为酰化试剂,在叔丁醇钾作用下得到烯醇前体。在三甲基氧鎓四氟硼酸盐(Me3O·BF4,Meerwein盐)和碱作用下进行选择性甲基化反应得到烯醇甲醚后,与胍在碱性条件下环化得到最终产物达拉匹林,并通过红外光谱、核磁共振对其结构进行表征。改进后的实验方法具有重现性好、毒性低、操作方便、实验微型化等优点。实验过程中不仅提升了学生的实验技能和科研思维,更提高了学生的创新能力和绿色环保意识。     

The glucocorticoid derivative with the phthalimide group cationic nanocrystal for ophthalmic application: a design space development approach

The glucocorticoid derivative of budesonide with a phthalimide group is a drug candidate to treat inflammatory eye diseases; nevertheless, it presents low water solubility. Drug nanocrystals have been proposed to overcome this hurdle. The development of an innovative ophthalmic anti-inflammatory nanosuspension was performed using a design space approach. We obtained the particle size reduction of this glucocorticoid derivative on a nanometer scale (approximately 165.0 nm), applying wet bead milling on a super reduced scale. The design of experiment supported the optimization of the formula evaluating the parameters that influence reducing the particle size and also allowed determining the design space. Considering the two statistical models developed and the size range obtained, we proposed that the optimized formulation for the glucocorticoid derivative nanosuspension may be 1.0 wt% glucocorticoid derivative and 0.092 wt% cetylpyridinium chloride. This formulation was characterized by the morphological, physical–chemical, and mucoadhesive in vitro test and showed potential for ophthalmic use with reduced frequency of product application, improved efficiency, and safety, which may promote better patient compliance.     

微视频技术在基础化学实验教学中的实践应用

以高校基础化学实验"从海带中提取碘""三草酸合铁（Ⅲ）酸钾的制备"为例，分别探讨了微视频技术在化学基本操作实验和综合设计型实验中的具体应用；此外，举例说明利用Flash软件制作的虚拟微视频可以在仪器分析实验中清晰地再现仪器真实操作中的每一个步骤，弥补了学生在实验前无法实际操作仪器的不足。实践证明，微视频技术的应用，丰富了基础化学实验教学模式，增强了学生自主学习的能力和动手能力，提高了实验成功率和实验教学效果。     

综合设计性专业实验:离子液体[BMIM]Br的制备及在柴油脱硫中的应用

在微波辅助下合成、纯化了离子液体溴化1-甲基-3-丁基咪唑[BMIM]Br，测定了产率和纯度，并使用FTIR和1HNMR进行了产物结构表征；以[BMIM]Br为萃取剂对催化裂化和加氢裂化柴油进行超声辅助萃取脱硫，并测定了脱硫率；在反应条件优化、测试方法优化、脱硫选择性等方面设置了多个开放性设计实验。该实验项目融合精细化工和石油化工方向，在促进学生知识体系跨界，全面训练综合实验技能，培养学生解决实际问题能力以及科研能力形成等方面作用明显；实验项目以模块化设置，符合"绿色实验"原则。     

4,4'-[(2,2-二苯乙烯)-1,1-双(4,1-亚苯基)]二吡啶的合成、表征及其聚集诱导发光性能研究

以提升学生的实验操作及创新能力为目的的综合化学实验，采用简单的2步法（缩合和Suzuki反应）合成了一种具有聚集诱导发光性能的化合物4，4'-[（2，2-二苯乙烯）-1，1-双（4，1-亚苯基）]二吡啶（简称2Py-TPE）。利用过滤、洗涤、萃取、干燥和柱层析等常用的有机分离操作手段对该化合物进行纯化；使用核磁共振仪、高分辨质谱仪、红外光谱仪及稳态瞬态荧光光谱仪对其进行结构表征和聚集诱导发光性能研究。该实验不仅可以促使学生了解以四苯乙烯衍生物为代表的聚集诱导发光材料的研究现状，而且能够培养学生的综合实验能力和科学探究能力。     

Advanced statistical evaluation of the complex formation constants from electrophoretic data II: Diastereomeric ion-pairs of (R,S)-N-(3,5-dinitrobenzoyl)leucine and tert-butylcarbamoylquinine

Intermolecular association and ion-pair formation, respectively, between a cationic chiral selector, viz. o-9-(tert-butylcarbamoyl) quinine (CQN), and the both enantiomers of anionic N-(3,5-dinitrobenzoyl)leucine, (R)-DNB-Leu and (S)-DNB-Leu, were investigated by affinity capillary electrophoresis (ACE). Thus, binding constants of the both diastereomeric ion-pairs, (R) and (S)-DNB-Leu/CQN associates, were determined by different experimental setups and correction of nonlinear effects. A reciprocal setup was employed for the high-affinity (S)-enantiomer, and the experimental mobility data obtained for CQN at variable (S)-DNB-Leu concentrations in the background electrolyte were linearized and evaluated by advanced statistical model. A binding constant of K_S=125.1 l mol⁻¹ was afforded. The constant for the (R)-enantiomer, which is outside the range suitable for direct affinity CE, was obtained from indirect affinity CE utilizing the separation of the DNB-Leu racemate at a single appropriate CQN concentration in the BGE (resolution method) taking advantage of the known constant for the (S)-enantiomer yielding a binding constant of K_R=2.51 l mol⁻¹. Thereby, the so-called “constant time method” was adopted for the required precise measurement of the effective mobilities of the both enantiomers. A combined approach of reciprocal affinity CE with racemic DNB-Leu as additive and the resolution method confirmed the results. The resulting constants evidence excellent enantioselectivity of the tert-butylcarbamoyl derivative of the cinchona alkaloid quinine as chiral selector for N-(3,5-dinitrobenzoyl) derivatives of amino acids.