内套式有毒气体实验装置

针对现行教材中有毒气体制备及其性质检验实验的不足,制作了适用于多种有毒气体实验的教具,使得实验变得更加安全、环保。     

密闭式有毒气体系列实验装置

设计目的在进行硫化氢、二氧化硫,氯气等演示实验时,这些有毒气体常常容易逸出,污染了室内空气,损害了师生健康。为了尽量减少有毒气体的外逸,我们设计了本实验装置。     

一套装置多处妙用

在高一化学教材《化学1（必修）》的“非金属及其化合物”一章中,涉及氯气（Cl2）、二氧化硫（SO2）、氮的氧化物（NO、NO2）、氨气（NH3）等有毒气体的实验较多。这些气体实验,学生、教师都很担心中毒。在教学实践中,本人用一套普通的装置（见图1）,多次在有毒气体的制取和性质实验中使用,有效地解决了有毒气体的污染问题（图中的试管可根据实验需要选用完好试管或底部破损有孔的试管）。     

制取乙炔实验的改进

1.降低化学反应速度,获得平稳气流。２.吸收有毒气体,避免环境污染。     

一氧化氮——一种重要的生物活性分子

讨论了一氧化氮在哺乳动物体内的作用，形成及其重要反应，以期使人们对这种过去只被看作是有毒气体的物质，有一个新的理解和认识。     

一种可控制污染的演示实验装置

课堂演示实验中常常产生有毒气体或臭味,污染空气。为避免污染,可采用如左下图所示的实验装置。这种演示实验装置是用带支管的试管加工而成的。     

一种有害气体的简易吸收装置

中学化学演示实验所涉及气体制备缺少一种有效的有毒气体吸收装置。现介绍一种有害气体的简易吸收装置,具体制作与使用如下:1.材料集气瓶一个、大号橡皮塞一个、玻璃弯管二根、橡皮管一段。     

探测有毒气体的碳纳米管

对有毒气体加燃烧或汽车尾气排放的二氧化氮 ( NO2 )等进行探测 ,与环境污染监视密切相关 ;同样的 ,氨气 ( NH3 )的检测对于工业、医疗以及家庭环境也很重要。而这些气体的检测则取决于所用的检测设备。新的研究表明 ,碳纳米管可探测到极少量的有毒气体 ,具有较高的检测灵敏度。通常检测 NO2 和NH3 时 ,需用几种物质与其反应从而进行这些气体的检测 ,但这些物质要在较高的温度下才敏感 ,JingKong等人观察到纳米管的电阻在室温下当纳米管与 NO2 或 NH3 接触仅几秒钟后即有较大的变化 ,所以纳米管有希望用于制造极小型的化学检测设备。…     

“硝酸跟铜反应”实验的改进

高中化学中的课堂演示和学生实验都安排了“硝酸跟铜反应”的实验,这些实验都是暴露在空气中进行的,反应产生的有毒气体散布在空气中。而且按课本中的实验方法很不易得到纯正无色的一氧化氮气体。     

饱和食盐水电解器的设计

电解饱和食盐水是中学学习电化学部分(电解原理)必做的实验之一.但该实验由于有有毒气体氯气生成,同时生成的2种重要产物都是气体,收集操作也不方便,笔者设计了以下实验装置,既可以方便地收集气体,又能防止毒气的排放.     

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.     

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.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.