不同提取方法对红茶提取物抗氧化活性影响的研究

采取沸水浴法、回流法、微波法及超声波法探讨信阳红茶和印度红茶的抗氧化性,通过测定吸光度利用Fenton反应表征提取物对羟自由基的清除率.不同的提取方法对红茶抗氧化活性有一定的影响,羟自由基的清除率与红茶的抗氧化活性成正比.结果表明:信阳红茶沸水浴法提取率较高,印度红茶超声波法提取率较高.     

信阳废次茶残渣对Au(Ⅲ)的吸附研究

研究了信阳废次茶对Au(Ⅲ )的吸附作用。考察了温度、酸度及时间等对吸附的影响。并比较了原茶和提取过有效成分后余下的茶残渣对Au(Ⅲ )的吸附作用。实验结果表明 ,信阳废次原茶与茶残渣对金都有很强的吸附性能 ,茶残渣优于原茶 ,且具有吸附速度快 ,吸附率高 ,温度影响小等特点。     

基于香气成分气相色谱-质谱指纹图谱的判别分析和相似度评价用于绿茶等级差异研究

该文以研究指纹图谱在绿茶等级判别方面应用的可行性为目的。以信阳毛尖茶为研究对象，以茶汤香气成分为研究目标，采用顶空固相微萃取与气相色谱-质谱联用技术，筛选其香气特征成分，建立不同等级信阳毛尖茶香气成分GC-MS指纹图谱。发现运用判别分析法可以对2个系列7个等级41个信阳毛尖茶样进行很好的等级区分；通过不同等级色谱指纹图谱的相似度计算发现，相似度与茶样等级之间具有较好的相关性，尤其是对于品质较好的茶样，这种相关性更好。表明运用判别分析法和相似度计算方法能够反映绿茶等级之间的差异性，且基于相似度评价的方法具有客观量化的特征。     

信阳废次茶残渣对Au（Ⅱ）的吸附研究

研究了信阳废次茶对Ａｕ（Ⅲ）的吸附作用。考察了温度、酸度及时间等对吸附的影响。并比较了原茶和提取过有效后余下的茶残渣对Ａｕ（Ⅲ）的吸附作用。实验结果表明，信阳废次原茶与茶残渣对金都有很强的吸附性能，茶残渣于原茶，且具有吸附速度快，吸附率高，温度影响小等特点。     

洗气瓶连接方法的改进

GB/T 223.69-1997钢铁及合金化学分析方法《管式炉内燃烧后气体容量法测定碳含量》需用两个洗气瓶,1#洗气瓶内盛高锰酸钾-氢氧化钾溶液,2#洗气瓶内盛浓硫酸。在天气变化明显或天气炎热季节,仪器夜晚停用后,常因1#洗气瓶内留有带压氧气加上高锰酸钾分解产生氧气会压迫洗液回流至缓冲瓶,污染连接管。因连接管大多用医用胶管,致使管子、洗液早期失效。每当回流现象发生,轻时更换连接管,严重时须更新洗液。为防止回流现象发生,本试验在仪器上加装两个Y型三通管(市场有售),连接方法见图1。图1洗气瓶连接方法Fig.1 New way of connection of gas washing bottles图1中单线为医用胶管,B为三通管。工作时把A处用夹子夹住,工作完毕放开夹子。用这种方法完全解决了洗液回流的问题。洗气瓶连接方法的改进@乐婷$河南二纺机股份有限公司!信阳464000 @朱俊青$河南二纺机股份有限公司!信阳464000 @于建$河南二纺机股份有限公司!信阳464000 @周珍琥$河南二纺机股份有限公司!信阳464000     

怀念生物化学家鲁宝重教授

鲁宝重教授是河南省新野县人。他生于1903年11月14日。1917年就读于河南信阳师范学校,毕业后,因成绩优异,考进了北京师范大学。1928年毕业后,先后担任河南安阳高中教员和开封师范教员兼教务主任。     

C_(60)敏化的顺-1,4-聚丁二烯的光氧化

Ｃ６０敏化的顺 １，４ 聚丁二烯的光氧化周涛陈双基（信阳师范学院化学系河南４６４０００）（北京大学分校化学系北京１０００８３）李子臣周锡煌李福绵（北京大学化学系北京１００８７１）关键词Ｃ６０，顺 １，４ 聚丁二烯，光氧化自从能以宏观量制备Ｃ６０...     

新型无机离子交换剂的研究：Ⅴ.偏磷酸铈的离子交换色谱法应用

新型无机离子交换剂的研究Ⅴ．偏磷酸铈的离子交换色谱法应用苏政权（广东药学院预防医学系卫生化学教研室广州５１０２２４）封惠侠（河南信阳教育学院化学系河南４６４０００）张秀莲（广东教育学院化学系广州５１０３０３关键词离子色谱偏磷酸铈分离中图分类号Ｏ６５７...     

应用醇-醚法使古代饱水的漆器和木器脱水定形的机理探讨

古代的漆器和木器大都被埋藏了数千年,长期受地下水的浸泡和菌类的侵蚀,朽烂和变质的很多。有不少漆器和木器已经残破,严重的甚至糟朽如泥。象殷商时期的漆器实物,仅仅留下残存的漆皮了。就是那些保存得较为完好的器物,虽然外表上看起来还艳丽如新,但是也多数饱含水份。例如,河南信阳地区战国墓     

关于“化学平衡”一节教学的研討

为了提高中学化学教学质量,最近在开封师范学院化学系和信阳函授站的主持下,选择了高中化学第二册“化学平衡”一节教材(1957年出版)进行了一次全专区性的观摩教学。由于在师范学院及函授站老师們的亲自指导下与全体函授教师集体备課,所以关于如何教好这一节课有一些体会,提出来与同志們共同研討。     

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.