高分子物理课程中的典型案例教学

案例教学法与传统教学法相比,具有自身的优点.本文针对影响高分子链柔顺因素的讲授,根据授课内容、方式和学时安排,就典型案例教学实施,从典型案例教学的准备、典型案例教学过程等方面,对教师和学生提出的要求进行合理的安排.并阐述了典型案例教学的益处,说明应用案例教学可以达到事半功倍的效果.     

案例教学法在分析化学理论教学中的实践研究

研究了案例教学法在分析化学理论教学中的实践,内容包括案例选材、设计、实施和案例模型评估。案例教学法模式在促进学生扎实学习理论知识的同时,改进学生对于分析化学课程的认知,提高学生的专业技能。案例教学法在分析化学理论教学中的实践可以在教师教学和学生学习之间建立良好的互动关系,并最终改善分析化学课程教学。     

香精香料化妆品通识课程案例教学的探索与实践

在香精香料化妆品通识课程中引入案例教学法的实践证明,案例教学法不仅能调动学生的学习积极性,加深对抽象原理或概念的理解和掌握,而且有助于提高学生分析、解决实际问题的能力,同时达到教学相长的效果。     

案例教学法在仪器分析教学中的应用

针对案例教学法在仪器分析教学中的应用,就案例如何选择、案例如何编写、案例如何实施等几个环节进行了阐释,并提出了自己的方案。     

PBL教学法在大学有机化学实验教学中的研究与实践

以苯甲酸正丁酯的合成为案例,将以问题为基础的教学法(problem-based learning,PBL)应用于大学有机化学实验教学。实践表明,PBL教学法能够显著增强学生的实验兴趣,培养学生的综合实验能力,提高实验教学质量。     

逆向案例教学法在普通化学教学中的应用及体会

分析了普通化学课程目前在教学环节所存在的问题,并针对这些问题提出了逆向案例教学法的改革举措。     

本科生与研究生环境化学课程教学内容和模式的差异

探讨本科生与研究生环境化学课程教学内容和模式上的差异,提出本科生教学以传授基础理论为主,以污染事件为切入点,强调系统性、趣味性和特色性,采用问题教学法、案例教学法和视频教学法等方法;而研究生教学以归纳总结知识点为主,关注研究热点和前沿问题,强调衔接性、主动性和应用性,采用互动教学法、体验教学法、文献归纳法等方法。     

任务情景教学法在化学教学中的应用

任务情景教学法是一种突出学生主体地位的教学方式,利于从真正意义上实现以学生为主体,切实培养学生的自主学习能力、实践能力和创新能力的理念。结合案例研讨了在高中化学教学中运用任务情景教学法引导学生进行自主探究,实施合作学习并培养学习能力的相关举措。     

大学无机化学实验教学中“问题导学”教学法的探索

介绍了"问题导学"教学法在大学无机化学实验教学中的实施要点,并结合硫酸亚铁铵制备实验教学案例,详细探讨了这一教学法在大学无机化学实验课堂教学中的具体实施策略。     

“案例教学法”在中职卫校化学教学中运用的探讨

化学在卫生学校是一门重要的基础课。结合实践,探讨了在中等卫生职业学校化学教学中运用案例教学法的意义和作用,并提出了一些实施的举措。     

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%.     

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.     

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.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.     

Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water

A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.     

Construction of polyheterocyclic spirotetrahydrothiophene derivatives via sulfa-Michael/aldol cascade reaction

A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).     

Suzuki-Miyaura reactions of the soluble guanylate cyclase inhibitor NS2028: a non-product specific route to C-8 substituted analogues

Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO₄ oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.