氨气制备和性质的微型组合实验

利用微型气体实验仪设计了氨气的制备和性质的微型组合实验装置,依次探究了氨气的制备、收集、检验和氨气还原氧化铜、氨气的喷泉实验等,观察到了氨气还原氧化铜的实验现象。具有操作简便,现象明显,安全环保等特点。     

适合学生探究氯气性质的微型实验装置

氯气的制备及其化学性质的研究是高中化学课程中的重要部分。然而,氯气的毒性和危害是学生亲自进行氯气制备和性质实验的最大障碍。本文运用微型实验的思想对氯气的制备和性质实验装置进行了精心设计,大大降低了氯气的危害程度,达到了能让学生安全操作的水平;同时,该套实验装置也同样适用于其他有毒气体的制备和性质研究。     

乙炔的微型实验

利用气体实验微型装置设计了乙炔的制备、检验、收集和性质探究实验,主要包括实验用品、实验装置、操作步骤和安全注意事项等内容,具有简明易做、安全环保等优点,适宜于学生独立实验操作,有利于培养学生实验能力。     

电解法制备过二硫酸钾的微型实验研究*

采用硫酸钾-硫酸水溶液为电解液制备了过二硫酸钾。以硫酸钾和浓硫酸反应原理和硫酸氢钾溶解度为基础对电解液的配制方法进行了改进。改进后耗时少,操作简便。采用微型实验和单因素实验探讨了硫酸钾与硫酸配比、时间、电流密度、温度对过二硫酸钾制备的影响。结果表明,微型实验药品用量至少减为原来的五分之一,仪器小型化易得,节能环保,实验效果良好;制备过二硫酸钾的较适宜条件为:硫酸钾与硫酸配比50%、电解时间1.0 h、电流密度1.0 A/cm2和电解液温度-4 ℃;产率20.7%,纯度92.4%。教学改革后学生实验兴趣和主动性大增,绿色化学理念加深,设计实验和探究能力及团队意识增强。     

8-羟基喹啉制备实验装置的改进

针对传统8-羟基喹啉制备实验装置存在的不足,在现有大学有机化学教学实验的基础上,重新设计一种8-羟基喹啉合成的实验装置,该装置利用自制的微型小漏斗和常规磨口玻璃仪器连接组装。解决了8-羟基喹啉制备实验中,后期未反应的邻硝基苯酚处理和8-羟基喹啉分离问题。实验结果表明,改进后的实验装置操作简便,安全,节省时间,实验效率明显得到了提高。     

二氧化氮与水反应的微型实验

利用气体实验微型装置设计了二氧化氮与水反应的一个定量化的微型实验,能够使二氧化氮多次被水吸收转化为硝酸,适宜学生独立实验操作,较好地实现了实验探究活动目标。     

微型化学实验与常规实验的比较研究

通过对2个有机化学实验的常规实验与微型实验加以比较,说明研究和推广微型实验的必要性. 1实验部分 (1)实验内容:乙酸乙酯的制备和苯甲酸的制备. (2)实验方法:常量法,实验方法见文献[1];微量法,实验方法见文献[2].     

多功能微型气体制备实验装置的设计研究

传统的气体制备实验装置是由一套玻璃器材组合而成,而这些玻璃装置的体积较大且易破,而且在实验前的准备与实验中的操作皆有不便之处,做实验时若一不小心便会弄破。由于延续等的制备与其性质的检验不易,实验过程较费时间,耗用药品也较多,并且也较易产生更多废液而造成污染。本文中所设计改进而成的实验装置“多功能微型气体制备装置”。其实验装置器材简单、制作容易、操作方便、效果显著又正确,此外又可减少很多药品,使用过的药品也可回收再重复使用,降低污染,真可谓是具有减量减废环保理念的绿色实验,实值得推广。     

实验室快速制备乙烯并检验其性质

利用乙烯利快速制备乙烯并检验其性质,并设计乙烯催熟果实的实验。改进后简化了乙烯的制备方法,实验现象明显,提高了实验的趣味性。微型实验的设计可以让学生进行实验探究。     

微型氢气制备装置之设计

利用塑胶滴定管、塑胶注射筒、三通塑胶活栓、双通塑胶活栓、塑胶罐及一些小零件等,设计组合而成一套可兼制备氢气和测定摩尔体积的微型氢气制备器,在短时间内可以安全、快速、正确地制备氢气、收集氢气、检验氢气及求出摩尔体积。制备氢气体积在10mL以内只需要少於1分钟的时间,求出氢气的摩尔体积的平均值为2494(Lmol),平均误差仅为2044%。且能以极为安全及富有趣味性的点燃法和氢气枪法来检验氢气的性质,其效果明显又正确。本实验已将传统的氢气制备法加以改进成一套微型氢气制备器,此套装置经试验的结果颇符合微型化学实验的10大优点(小—体积小、省—时间省、快—反应快、好—效果好、易—操作易、安—很安全、多—动手多、高—趣味高、少—用药少、低—污染低),此套装置很值得提供给化学教育界专家及化学教师们参考。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.