乙酸乙酯皂化反应实验数据处理方法对比分析

在电导率法测定乙酸乙酯皂化反应动力学实验中,不同的数据处理方法得出的结果不同。基于31组学生的原始实验数据,分别采用线性、非线性、指数等3种函数程序对测量数据进行拟合处理,从原始数据的测量、计算结果、相关系数等3个方面进行了对比。研究表明,后2种方法得到的结果比较接近,均优于第一种方法,且采用指数函数拟合法能够达到更好的拟合效果,获得速率常数和活化能的标准偏差也较小。采用多种数据分析方法,不仅提高了学生分析结果的准确度,而且拓展了学生对计算机软件的应用能力。     

n-InP在Fe3+/Fe2+溶液中复阻抗的计算机拟合分析

本文测定了不同电位及不同光强下, n-InP在Fe~(3+)/Fe~(2+)溶液中的复阻抗图, 从一个等放电路用计算机对结果进行了拟合, 并对拟合结果进行了讨论。     

新课程背景下初中生化学学习兴趣调查研究

兴趣是学生学习活动中最活跃的因素,是影响学生学习效果和身心发展的重要因素,也是心理学研究的问题之一。在参阅国内有关兴趣研究的基础上,结合教育学及心理学相关理论和初中化学学科特点,编制了《初中生化学学习兴趣调查问卷》,对河北省内的901名学生进行了调查。研究表明,新课程背景下,河北省内绝大多数初中生对化学学习是感兴趣的,而学生所处地域、学习成绩、家长文化程度的不同都使学生的化学学习兴趣有一些差异,而性别不同学生的学习兴趣没有差异。     

快扫循环伏安曲线的单纯形优化-数值模拟拟合方法

采用Gl算法改进了快扫伏安曲线的数值模拟,提高了模拟计算的速度.使用单纯形优化-数值模拟方法,以电流、峰电位误差的加权值作为拟合参数的评价函数,对二茂铁在0,3mm直径铂盘电极上,不同扫速下的循环伏安图进行了拟合.在拟合过程中自动进行伏安图基线的校正,同时拟合出标准非均相速度常数k~0,未补偿溶液电阻R_u以及双电层电容C_(dl)等重要的参数值,所得k~0值与文献报道结果一致.     

快扫循环伏安曲线的单纯形优化—数值模拟合方法

采用Ｇ１算法改进了快扫伏安曲线的数值模拟,提高了模拟计算的速度。使用单纯形优化－数值模拟方法,以电流、峰电位误差的加权值作为拟合参数的评价函数,对二茂铁在０．３ｍｍ直径铂盘电极上,不同扫速下的循环伏安图进行了拟合。在拟合过程中自动进行伏安图基线的校正,同时拟合出标准非均相速度常数ｋ＾０,未补偿溶液电阻Ｒｕ以及又电层电容Ｃｄｌ等重要的参数值,所得ｋ＾０值民文献报道结果一致。     

新课程背景下对高中学生化学学习兴趣的调查

学生的学习兴趣是激发学习动机的重要因素,新课程十分重视对学生学习兴趣的培养。对不同程度的学生在学习新课程时的学习兴趣研究,有助于从学生角度出发反思课程改革和课堂教学。用兴趣量表对浙江省的重点中学和非重点中学学生的化学学习兴趣进行对比调查,结果显示2所学校的学生对化学新课程的学习兴趣有异同。     

中德初中化学教材中“原子”编写的比较

原子是初中化学课程的重要知识内容,是初中学生学习的重点和难点之一,不同的教材内容和编排对学生的学习有着不同的效果。本文从内容体系、编写思路、呈现方式3个方面对中国和德国的4种初中化学教材中“原子”的编写进行比较。     

PCK视域下高中化学教师“学生知识”的调查研究与分析

化学教师的"学生知识"是教师学科教学知识(pedagogical content knowledg,简称PCK)中的重要组成要素,是实现化学有效课堂教学的必要条件。以新课标教材《化学1》"氧化还原反应"概念学习内容为载体,对PCK视域下湖北、重庆、四川、安徽4个省市的部分高中化学教师进行"氧化还原反应"概念学习内容"学生知识"的现状进行了调查;并对调查结果采用独立样本t检验法、单因素方差法以及一元线性回归分析法进行分析,分析结果表明教师性别、教龄、学历3因素对"学生知识"有显著影响;学习基础、学习过程、学习结果各维度对"学生知识"有不同程度的影响;最后针对教师"学生知识"存在的问题进行分析并提出了相关的改善建议。     

SigmaPlot软件在物理化学实验中的应用

SigmaPlot软件功能强大,使用方便、快捷,普遍用于数据分析和科研绘图。将其应用到物理化学实验数据处理、计算以及对所作的图形进行线性拟合、非线性曲线拟合,不仅简化了数据处理的过程,而且还提高了分析结果的准确度,同时也可以培养学生运用现代技术手段学习物理化学实验科学规律的能力。该文以物理化学实验教学中相关实验数据处理为例,探讨了SigmaPlot在物理化学实验教学中运用的基本原理和方法。     

应用Suzuki偶联反应学习Hammett方程的实验教学设计

介绍了一个有机化学综合创新实验——应用Suzuki偶联反应来学习Hammett方程的实验教学方案。通过探究不同取代基底物对Suzuki偶联反应速率的影响,进一步得出Hammett方程的关系曲线图,结果表明苯硼酸上的吸电子取代基使反应速率减慢,而给电子取代基会加快反应速率,探索了Suzuki偶联反应中转金属化过程对偶联反应的影响。在进行文献调研、实验设计、实验操作、结果分析和报告撰写的过程中,学生既能学习Suzuki偶联反应的基本原理,更重要的是理解Hammett方程的意义,激发学生对有机化学的科研兴趣,提升学生综合素质。     

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.     

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.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.