农林高校基础化学多层次课程体系和教学内容的改革与实践

以农林高校基础化学课程体系和教学内容改革为抓手,构建了农科特色鲜明的多层次课程体系,优化设计了教学内容,增强了教学的针对性,突出了学生个性的发展,为农科院校创新人才的培养奠定了重要的化学基础。     

酰胺基团对Gemini表面活性剂表面活性和聚集行为的影响

本文合成了含酰胺基团和不含酰胺基团的两类Gemini阳离子表面活性剂,测定了其表面活性参数,研究了酰胺基团对表面活性剂的表面活性和聚集行为的影响。结果表明,酰胺基团提高了Gemini阳离子表面活性剂的临界胶团浓度,降低了胶团聚集数,增强了胶团微极性,增大了表面活性剂的饱和吸附量。     

前言

自20世纪初期,德国化学家EmilFischer首先合成了甘氨酸二肽片段,并第一次提出“peptide”（多肽）这一名词,多肽化学的研究已经历了100多年的发展．1953年,Vigneand小组首次完成了生物活性肽催产素的合成,并因此于1955年获得了诺贝尔化学奖．1963年,Merrifield提出了多肽固相合成法,并发明了第一台多肽自动合成仪,大大简化了多肽合成的流程、提高了合成的效率,从而促使多肽化学实现了飞跃式发展,Merrifield也因此获得了1984年诺贝尔化学奖．1965年,我国科学家完成了牛结晶胰岛素的合成,     

新课程改革背景下南宁市高中化学教师素质现状的调查与分析

在高中新课程改革的背景下,利用自行设计的问卷,对南宁市高中化学教师素质进行了调查,分析了其素质现状和特点,探索了素质优化途径,并根据调查结果,提出了相应的建议。     

食品安全与健康——深圳市卫生部门食品安全保障体系

回顾了国际国内的食品安全问题以及管理现状,着重介绍了深圳市卫生部门食品安全保障工作.近几年,深圳市有效运行了食品污染物监测网络,基本掌握了食品安全存在的问题,通过对问题食品的追溯,从根本上着手解决问题,控制了污染食品进入餐桌;以风险评估作为科学手段,做好重点食品污染物的监测预警;引导和提醒消费者提高自我保护意识,为政府制定相关决策提供了依据,从而显著地减少了食源性疾病的发生,有效地保障了公众的身体健康.     

钠在氯气中燃烧实验的改进

指出了现行高中化学教材中钠在氯气中燃烧实验的不足,详细介绍了改进后的实验装置及其实验方法,简化了氯气制备及其实验过程,保障了整个实验在封闭体系内进行,解决了钠在氯气中燃烧实验严重污染环境问题,从而培养了学生的环保意识。     

微粒运动实验创新设计与改进

对微粒运动实验的仪器、用品作了改进,重新设计实验装置,使实验装置达到了小型化、封闭化、简洁化,实验达到了绿色环保要求,满足了大面积的学生探究实验操作使用,取得了良好的效益。     

储氢合金电极的表面修饰研究

利用等离子体技术对AA型MH/Ni电池的储氢合金电极进行了镀覆导电膜层的表面修饰,用XRD及SEM对电极结构进行了表征.极片经过表面修饰的电池,其内阻降低了24％,放电容量有了明显提高,5C (7.5 A) 放电容量提高了200 mA•h,放电平台电压提高了约0.14 V,导电膜层还起到了电极保护层的作用,抑制了合金的粉化,提高了电池的循环稳定性.同时,电池内压显著降低,电池性能有了较大改善.     

Design of a PFW European type impact crusher

介绍了一种PFW欧版反击式破碎机,由于该机采用了重型转子装置,取得了较好的破碎效果。该破碎机结构科学合理,使用安全可靠,维护方便快捷。与传统反击式破碎机相比,不仅延长了设备的使用寿命,缩短了耐磨件的更换时间,而且提高了生产效率,增加了经济效益。     

过氧化氢对8-氨基喹啉衍生物-铜和钴荧光体系的增敏作用及机理研究

本文介绍了新合成的8-氨基喹啉三系列衍生物,系统研究了它们与铜和钴的荧光反应,发现了试剂取代结构对其荧光性能的影响规律,试验了过氧化氢对铜、钴荧光体系的影响,发现了其增敏作用,探讨了增敏机理。     

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%.     

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.     

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.     

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

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.     

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.