理解著文强化记忆——化学研究性学习过程中穿插诗歌教学的尝试

将诗歌引入到化学教学中,增强了学生对化学知识的理解,促使了学生对化学知识的记忆,加强了化学知识与社会、与相关学科的联系,是研究性学习的一种尝试。文中介绍了对在化学学习过程中穿插诗歌教学的理解与做法。     

培养学生记忆化学方程式的策略

在学习化学的过程中,长期困扰学生的一个问题是：如何记忆化学方程式?学生在学习中通常会陷入这样的误区：像记忆英语单词一样地记忆化学方程式。这样的行为结果不仅让学生感到苦不堪言,而且学习效率低下、学习兴趣降低,最终的结果必将导致认知水平不高。化学方程式在化学学科中所占的重要地位是每一个学习化学的人都能体会到的。掌握好化学方程式,是学好化学的基础。     

化学专业英语教学改革研究*——基于“在用中学”模式的探索与实践

化学专业英语是大学生在专业知识学习和创新、实践能力培养过程中常常会接触和应用到的。针对化学专业英语教学过程中的学生学习动力不足、知识记忆不牢等问题,结合学生们对化学专业英语的实际应用需求,介绍了化学专业英语教学团队在探索和实践“在用中学”的专业英语课程教学新模式过程中的经验和反思。     

认知理论视域下的化学专业英语词汇教学

化学专业英语词汇通常被认为是跨学科教学的难点。将认知理论视域下的有意义学习、概念隐喻理论、范畴理论、框架语义学等引入化学专业英语词汇教学不但可以提高学生对化学专业英语词汇的记忆、理解,而且可以激发学生的学习兴趣。     

高中学生化学学习元认知水平的调查与分析

在平时教学过程中,我们比较注意研究高考要求、教材和教法,同时也注意研究学生的记忆力、注意力和想象力以及思维能力等在化学学习过程中的作用,把学生的学习过程理解为是对化学知识进行感知、记忆、理解、加工的过程。     

乙二酸受热分解的探究性教学

1主题与背景《普通高中化学课程标准(实验)》指出:有效的化学学习活动,不能单纯的依赖、模仿与记忆。动手实践,自主探索与合作交流是学生学习化学的重要方式。在新课程理念下,我们必须改革课堂教学,把思考还给学生,让学生成为课堂的主人。在课堂实践中尝试让学生进行探究性学习     

在化学教学中应重视培养学生的表达能力

《全日制中学化学教学大纲》明确指出：“在化学教学中要重视发展学生的智力,培养学生的能力”。戴安邦先生在“全面的化学教育和实验室教学”一文中将智力因素分为7种能力,即：动手、观测、查阅、记忆、思维、想象、表达,其中思维能力是智力因素的核心。     

学生对离子反应概念的认识研究

化学概念是物质及其变化等的抽象或概括,其根本意义在于提供了一种分析问题和解决问题的新方法。学生学习化学概念,不仅是对具体概念的辨析和记忆,更为重要的是要建立起对概念的理解,将化学概念作为认识问题的工具和方法。针对高中化学1“离子反应”概念的学习,从概念的认识、概念的应用2个层面,就学生对于离子反应概念认识中存在的问题进行了探查和分析,提出了相应的教学对策。     

在垃圾分类中寻找化学元素*——基于生活情境的探究性学习

介绍一个结合4种教学策略(情境教学、探究性学习、合作学习、混合式教学)面向非化学专业类大一学生开展元素化学教学的案例。以垃圾分类为主题,学生分组协作完成探究性学习任务,调查不同种类垃圾中存在的化学元素及其用途,通过线下课堂展示、线上成果共享以及校外推广等3项活动传播探究结论。对比活动前后收集的数据,活动前有75%的学生只认识原子序数前20的化学元素,活动后学生认识的元素数量明显增多,平均值是原来的1.7倍。元素中文名称与元素符号记忆混乱的情况得到改善。最后问卷调查表明活动提高了学生上课的积极性并且对了解生活中的化学元素有帮助。     

如何激发学生学习元素化学的兴趣

元素化学的内容庞杂、琐碎,学起来枯燥乏味,记忆困难,学生不感兴趣。爱因斯坦说：热爱是最好的老师。因此,如何激发学生学习元素化学的兴趣,充分发挥其主观能动性,成为“无机化学”教学中的重要课题。     

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.     

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.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

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.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.