西藏高中化学实施探究式教学及科学素养评价策略研究

研究者调查了西藏地区高中生科学素养状况,提出了在西藏高中化学中开展探究式教学的实验来提高学生科学素养的设想,通过一个学期的教学实验,发现探究式教学是提高学生科学素养的有效途径,值得在西藏地区推广,同时研究者还提出了科学素养的评价策略和西藏教育中的问题。     

高中化学实验教学中过程性评价多元化的实践与思考

在高中化学实验教学中尝试采用不同的过程性评价手段,探讨实验教学中过程性评价应用的意义,促进学生的学习观和教师的教学观的转变,促进学生化学科学素养的形成和发展。     

对高中化学新教材的研究与实践

本文通过对高中化学新教材的初步研究,从化学理论螺旋式编排、培养科学素养、强化实验教学、联系社会实际和重视能力培养 5个方面概括了新教材的特点阐述了教学实践的体会。     

从对转基因的认识谈高中学生科学素养的培养

高中化学和生物教材有多处介绍核酸、基因、转基因的知识,但通过问卷调查发现：高中学生对基因、转基因技术和转基因食品的认识模糊不清。究其原因可能是由于教学的功利性,仅关注本学科的高考,不注意学科间知识的融会贯通,不重视学科前沿知识和社会热点问题的拓展。高中化学课程中应重视“核酸”等生命化学相关内容的教学,拓展学生对转基因技术的科学认识,引导学生运用所学知识和科学方法去分析、判断转基因食品的安全性问题,着眼于培养学生的科学素养。     

对高中化学新教材的研究与实践

本文通过对高中化学新教材的初步研究,从化学理论螺旋式编排、培养科学素养、强化实验教学、联系社会实际和重视能力培养5个方面概括了新教材的特点阐述了教学实践的体会.     

基于化学史与多媒体技术整合的氯气教学设计

化学教学中渗透化学史是提升学生科学素养的有效途径。研究选取了高中化学"氯气"一节为例, 沿着氯气发现史设计了多媒体课件, 以动画的形式重现氯气的发现、性质研究到应用开发的历史过程, 通过课件创设的启发提问-探究讨论-归纳总结等活动来深入挖掘化学史背后蕴藏的化学知识与原理, 使学生在体验科学探究过程、培养科学思维与方法的同时学习氯气的物理性质和化学性质, 进而体现了利用化学科学史与多媒体技术整合制作多媒体课件来培养学生科学素养的新教学探索途径。     

对高中化学新教材的研究与实践

本文通过对高中化学新教材的初步研究。从化学理论螺旋式编排、培养科学素养、强化实验教学、联系社会实际和重视能力培养5个方面概括了新教材的特点阐述了教学实践的体会。     

改革开放以来我国高中化学教科书中科学家内容的变迁与启示*

教科书中科学家内容是增进学生化学学科理解、加强科学本质教育、发展科学素养的重要载体。从数量、呈现位置、呈现内容等维度分析改革开放以来5套典型高中化学教科书中的科学家内容,总结我国高中化学教科书中科学家内容变迁的特点,挖掘其中的教育价值,以期对教科书中科学家内容的编写和化学教学有所启迪。     

促进科学观念与科学实践协同发展的学生必做实验的教材编写

国内外科学教育界普遍认为,科学观念与科学实践的协同发展是培养学生科学素养的重要途径。教材对于学生必做实验的编排和处理,对于教师的教学设计及实施具有重要的影响。简要介绍了科学观念与科学实践协同发展的内涵,并针对北京师范大学“新世纪”山东科学技术出版社高中化学必修教材中的学生必做实验编写的整体情况和具体策略进行了深入分析,阐释了该教材对于学生必做实验的编写是如何体现科学观念与科学实践的协同发展、彰显这些实验的核心素养发展功能的,并提出了新教材学生必做实验的教学实施建议。     

高中化学教科书中科学素养主题的定量分析

运用内容分析法对高中化学新、旧教科书中的科学素养主题进行分析,得出科学素养主题内容发生了较大的变化;传统高中化学教科书的编写注重知识与技能,对科学过程与方法的关注不够;新高中化学教科书的编写突出了科学过程与方法,拓展了科学、技术与社会的相互关系。     

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.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

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.     

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.     

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.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.