提高分析化学课堂吸引力的教学策略

课堂是老师和学生交流的主要场所,在高校分析化学的课堂教学中,教师可以从转换专注与发散2种学习模式、合理利用图形背景原则、课堂执行Chunk学习法、提倡课堂高效自主学习及开展课堂讨论、自主完形闭合等几个方面入手,让学生成为分析化学课堂的主人翁,真正吸引他们投身其中。     

通过课堂观察法比较中等生和优等生的化学课堂学习行为——以"弱电解质的电离"为例

课堂是学生学习的主要场所,本研究通过观察一节化学常态课,对比分析中等生和优等生的化学课堂学习行为.研究发现:学生在化学课堂上体现的主体性不明显,课堂活动以教师为主;优等生在化学课堂表现出学习的投入程度、专注度都比中等生要高;中等生已有的认知结构、元认知策略的不足以及畏难情绪大大影响了他们课堂的有效学习;小组合作学习能大...     

化学学科视域下课堂互动双编码模型的应用研究

以弗兰德斯互动分析系统为理论基础,构建了具有化学学科特征的课堂互动双编码分析模型。以获得安徽省高中化学优质课大赛一等奖的1名优秀新手型教师和1名专家型教师的课堂为例,从课堂互动矩阵、动态折线图、课堂互动变项、教师表征转换水平等4个方面的比较与分析入手,全面介绍了该双编码模型在课堂分析中的应用。     

高中化学课堂学生活动有效性研究

课堂是学生学习的主渠道,课堂教学质量的高低决定了学生的学习质量。学生是课堂教学的主体,学生活动是课堂教学的主要形式和内容。因而,学生课堂活动的质量是教学质量高低的决定性因素。目前,课堂学生活动存在两种极端现象,一些教师在教学设计中过于详尽地策划了自己教的过程,而忽略了学生学的过程,学生活动设计不足,不能体现学生的主体性;有的“为活动而活动”,设计了过多的课堂学生活动,许多活动是散漫的、随意的、肤浅的,局限于表层的活动。而教师们之所以较少设计学生活动,或学生活动的品质差,是因为他们在这一领域还缺乏对课堂学生活动重要性的认识,对课堂学生活动设计的原则、策略理解不全面,不深刻。总之,在这一领域还缺少有效的教学策略。针对学生活动有效性缺失的现象,本课题组通过理论分析和课改实践,对高中化学课堂学生活动有效性进行了研究,内容包括高中化学课堂学生活动的原则、学生课堂活动的要素、高中化学课堂设计学生活动的原则与策略等。     

化学课堂探究教学“制订计划”的评价

为了解化学课堂探究教学“制订计划”的有效性,在课堂观察与分析的基础上,提出化学课堂探究教学“制订计划”系统分析量表,并结合具体化学课堂探究教学,从计划制订的主体、计划制订的过程、计划内容本身等3个方面解析了“制订计划”环节。结果启示：化学课堂探究教学“制订计划”系统分析量表能科学有效地指导化学课堂探究教学,特别是其“制订计划”的设计、实施与评价。     

例析高中化学“翻转课堂”与“传统课堂”教学之利弊

“翻转课堂”是一种新兴的教学模式,与“传统课堂”相比,2者各有利弊。以“氢氧化铝的性质”等教学案例为例,阐述“翻转课堂”在“满足不同水平学生的需求”、“培养学生自主学习能力”、“实施一对一个性化辅导”及“演示实验教学”上的优势,“传统课堂”在“利用探究实验培养学生科学探究能力”、“态度、情感等隐性知识的传授”上的优势;提出将“翻转课堂”应用于高中化学教学时,应研究其适时性、合理性的观点;主张将2种模式相互渗透,设计完美“翻转课堂”。     

以任务或项目为驱动的翻转课堂——3种模式在国际高中化学教学中的实践

基于3种类型的翻转课堂——任务导向型翻转课堂、展示型翻转课堂和项目驱动式翻转课堂在国际高中化学课程中的实践过程,探讨了如何在把握以学生为中心的翻转课堂本质的基础上,通过融入任务导向或项目驱动进一步发挥教师的专业引导作用,强化课前和课内连接而成的有机整体,将学生个性化自主学习的效率最大化,并最终引导学生成长为有后续学习能...     

关于化学课堂提问的思考

新一轮基础教育课程改革给课堂提问赋予了新的内涵,在新的课程理念下,教师应该重新审视课堂提问,合理设计课堂提问,通过提问促进课堂上的交流,发展学生的思维能力和解决问题的能力,使提问成为师生共同发现、理解和探究知识的重要途径.     

物理化学教学模式的探索与实践

在当今高等教育创新人才培养要求下,结合国内外教育先进技术方法,通过物理化学教学实践,探索了讲授课堂、翻转课堂、对分课堂等3种教学模式,教学实效性结果表明,开放式的教学更利于提高教学质量,对分课堂教学模式更适合于我校学生学习物理化学。     

《天工开物》在化学课堂中的应用*

分析了传统文化进入化学课堂的可能性和必要性,对《天工开物》与高中化学契合的内容进行整理,列举其在化学课堂导入、工艺流程教学及试题编制等方面的应用并运用于实践,并就如何促进传统文化更好地应用于化学课堂提出建议。     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

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.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

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%).