鲁氏毛霉发酵产物壳聚糖硫酸酯化的研究

利用鲁氏毛霉(Mucor rouxii)3.2545发酵产生壳聚糖,然后用氯磺酸/甲酰胺方法对壳聚糖进行硫酸酯化,当底物壳聚糖用量为1g时,其最佳反应条件为:10mL甲酰胺中氯磺酸添加量为3.0mL;反应温度为70℃;反应时间为3.Oh.其中反应温度对反应的影响最大.在最适反应条件下,壳聚糖硫酸酯的硫含量可以达到16.04%.通过红外光谱分析,发现壳聚糖已经成功地被硫酸酯化,而且结构与肝素相似.此外,所得产物还具有抗凝血和抗血栓的性质,其抗血栓的性质优于肝素.     

酵母甘露聚糖硫酸酯化前后结构与生物活性比较研究

对酵母甘露聚糖及硫酸酯化酵酯母甘露聚糖的相对分子质量、红外光谱、离子色谱、比旋光度、IO4^-氧化、SO4^2-含量、Smith降解、电泳及THP－1细胞分泌IL-la的水平等进行了测定，结果表明，硫酸酯化后相对分子质量增加，IR光谱[α]D^20均有明显变化，电泳迁移加快，IO4^-氧化甲酸生成量减少，硫酸酯化位置在非还原末端，C（3）对碱位置稳定，Smith降解结果表明硫酸化前后基本结构无明显变化。硫酸酯化前后样品对THP－1细胞分泌IL－1a水平影响差异显，对IL-6,IL-8,TNFa,IL-2亦有影响。     

在铌酸催化剂上气相酯化反应的研究

氧化铌在含水体系中表现出强酸性,因而得到越来越多的应用。有机羧酸酯是一类重要的化工产品,一般用硫酸等作催化剂,但存在腐蚀设备等问题。我们采用铌酸催化剂进行乙醇和6种羧酸的常压气相酯化反应。实验表明,不仅乙醇转化性高,而且酯的选择率高达100％,同时,也克服了上述液体酸催化剂的缺点,有希望成为酯化反应的有效催化剂。     

从反应机理探究酯化反应教学疑问

从酸催化酯化反应机理入手,阐释试剂添加方案及同位素示踪法相关疑问。通过文献调研,以反应机理探究教材及高考试题中相关酯化反应的教学疑问,理清某些中学师生对酯化反应的模糊认识。     

蔗渣木聚糖丁香酸酯-g-AM/MMA/BA的合成与抗癌活性研究

以蔗渣木聚糖(BX)为主要原料,丙烯酰胺(AM)、甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)为接枝单体,过硫酸铵为引发剂,N,N-亚甲基双丙烯酰胺为交联剂,在水溶液中合成了蔗渣木聚糖共聚物BX-g-AM/MMA/BA;再以丁香酸为酯化剂,在N,N-二甲基乙酰胺(DMAC)有机溶剂中进行酯化反应合成蔗渣木聚糖丁香酸酯-...     

负载稀土型酸活化膨润土的酯化催化活性

负载稀土型酸活化膨润土的酯化催化活性李永绣，冯天泽，胡平贵，何小彬，辜子英，廖荣辉（南昌大学化学系南昌３３００４７）关键词稀土，膨润土，催化酯化可用稀土、膨润土单独作酯化催化剂，但活性不高［１～３］。本文将稀土用离子交换的方法负载到酸活化膨润土中，寻...     

聚乙烯醇与硬脂酸酯化反应及性能的研究

聚乙烯醇 (ＰＶＡ)具有良好的成纤成膜性能 ,膜的阻氧性、透明性、抗静电性、韧性、印刷性和耐化学性能优异 ,用途广泛 .ＰＶＡ的缺点是吸湿性大 ,耐水性差 ,熔融加工困难和热稳定性低 .吸湿后 ,ＰＶＡ的强度仅为其干强度的 55%～ 60 % ,膜的阻氧性下降 .ＰＶＡ在 1 60℃开始分子内脱水 ,2 30℃时开始分子间脱水变脆 .由于分子内和分子间有大量氢键存在 ,ＰＶＡ熔融温度高 ,不能熔融加工 ,而溶液成型工艺复杂、成本高、难于制备厚壁和形状复杂的制品 .降低熔融温度、提高热稳定性能是实现ＰＶＡ熔融加工成型的必要条件 .国内外在采用马来酸…     

鱿鱼墨多糖的硫酸酯化及抗凝血活性

本文采用三氧化硫吡啶复合物二甲亚砜法首次对北太平洋鱿鱼墨多糖SIP进行硫酸酯化。对硫酸酯化后多糖样品的基本化学组成进行测定,分析了糖组成,硫酸基含量和分子量。并结合红外光谱和一维核磁分析其结构,结果表明硫酸酯化主要发生在GalNAc的4,6位上。进一步的凝血活性分析表明有较好的延长APTT和PT时间效果。对凝血因子的抑制实验则表明,硫酸化后的鱿鱼墨多糖TBA-1对FIIa和FXa 均有显著的抑制作用。     

苯并咪唑衍生物的合成及其反应机理研究

以2,2’-(邻氨基苯胺基)丙烷和水杨醛为原料,经缩合、成环作用,依次得到双席夫碱化合物L1、含一个苯并咪唑基的席夫碱L2和含双苯并咪唑基的化合物L3。采用1H NMR光谱和X-射线单晶衍射技术对化合物L1～L3的组成与结构进行了表征,推测了形成苯并咪唑衍生物的反应机理。结果表明,苯并咪唑衍生物的形成是热力学控制的。文中还对系列化合物L1～L3的UV-Vis和荧光光谱进行了考察。     

胺烷基二茂铁环钯化反应研究

通过一系列实验探讨了胶组分的电子效应与空间结构、反应的投料比、体系的温域等因素对反应的影响．发现了违反Cope准则的现象，阐明了胶组分的电子效应和空间结构、体系的酸碱度和体系的温域是决定生成坏钯化产物的重要因素．     

Influence of particle size distribution on thermokinetics of ilmenite with sulphuric acid reaction

The knowledge about kinetics of the reaction titanium raw materials with sulphuric acid is very important from the reason of influence of initial conditions of reaction on efficiency, quality and safety. One of the very important parameter, which influence on kinetics of this reaction is distribution of particles sizes of raw material. Presented results of investigation of reaction thermokinetics of ilmenite with different particles sizes, obtained in special construction of calorimeter, demonstrated very great influence of this parameter on rate of reaction with sulphuric acid. On the base of experimental investigation the kinetic model of this reaction was elaborated which takes into account density of particles sizes distribution described by the function of Rosin–Rammler. Presented model was tested on the base of experimental data of ilmenite with sulphuric acid reaction.     

荧光素和苯磺酰氯间反应机理研究

在N,N-二甲基甲酰胺存在下,荧光素和苯磺酰氯间的反应经历串联两步:首先荧光素被苯磺酰氯酯化,然后生成的氯离子亲核进攻芳碳,取代苯磺酰氧基,后者是良好的离去基团。反应的结果是氯取了荧光素的酚羟基,反应机理由本工作找到的关键中间体证实。     

Investigation of reaction products of sulphuric acid with ilmenite

The reaction of sulphuric acid with titanium raw materials runs violently with simultaneous emission of gases. Such run of reaction creates danger of explosion. This process is very complicated from the reason of complexity of reactions and variety of compounds in reaction mixture. To determine safe conditions of reaction with high efficiency, it is necessary to investigate phase composition products of reaction. Products of reaction were investigated by using X-ray diffraction. However reaction products show high amorphy and this is the reason of difficulties to determine all phases. For this reason also was used additional method — ‘drop’ calorimeter. This method is used for determination of average specific heat of liquid or solid samples. In this case, this method was used for verification of phase composition of products of reaction. On the basis of investigation the phase composition of reaction product is following: titanyl sulfate, iron(III) sulfate, monohydrated iron(II) sulfate, magnesium sulfate and unreacted remainders of ilmenite and magnesium silicate.     

Polyethersulfone sulfonated by chlorosulfonic acid and its membrane characteristics

Sulfonated polyethersulfone (SPES) was prepared by homogeneous method with chlorosulfonic acid as sulfonating agent and concentrated sulfuric acid as solvent. The presence of sulfonic acid groups in SPES was confirmed by ¹H NMR and FTIR. Thermogravimetric analysis (TGA) studies were carried out to investigate the thermal stability of SPES. Membranes were cast from SPES solutions in N-methyl-2-pyrrolidone. Tensile strength of prepared membranes decreased with degree of sulfonation (DS) but water uptakes of SPES membranes increased with DS. Compared with unsulfonated polyethersulfone membrane, the hydrophilicity of SPES membranes was increased, as shown by a reduced contact angle with water. Amorphous structures for SPES membranes were detected by X-ray diffraction. Atomic force microscopy phase images of the membranes clearly showed the hydrophilic domains at higher DS.     

Kinetics and mechanism of chelating reaction between chitosan derivatives with Ca(II)

Chitosan derivatives, such as chitosan alpha-ketoglutaric acid (KCTS) and hydroxamated chitosan alpha-ketoglutaric acid (HKCTS), are prepared and their coordination behavior toward Ca(II) was studied. The adsorption isotherms were correlated by dc/dt?=??kcⁿ at 20°C, 30°C, 40°C, 50°C, and 60°C. By linear correlation, the shapes of the isotherm curves were similar to the kinetic function of 1/c?=?kt and the rate equation was dc/dt?=??kc ²; the activation energies were 13.31 and 14.76?kJ?mol^?1 for KCTS and HKCTS, respectively. The overall rate of Ca(II) adsorption is likely to be controlled by the chemical process. The coordination mechanism of chitosan derivatives with Ca(II) was studied by infrared and X-ray photoelectron spectroscopy. The results indicated that –NH– of KCTS was coordinated. Nitrogen of amino, oxygens of hydroxamic acid, and carbonyl in HKCTS coordinated with Ca(II).     

改进的Ugi法合成胺烷基二茂铁衍生物的反应研究

在改进的Ugi法会成胺烷基二茂铁衍生物的反应中，研究了反应的投料比、反应底物、反应温域等因素对反应的影响，并对反应机理进行了探讨。     

BrO与CH3SH反应机理的量子化学及拓扑研究

利用密度泛函和电子密度拓扑分析方法对BrO与CH₃SH反应的微观机理进行了理论研究. 在B3LYP/6-311G (d, p)水平上对反应势能面上的各驻点进行几何构型的全优化; 振动分析和IRC计算证实了中间体和过渡态的真实性和相互连接关系; 计算得到了各反应通道的活化能, 并进行了零点能校正. 计算结果表明: 该反应存在7个反应通道, 其中生成CH₃S＋HOBr和CH₃SO＋HBr的通道为主要反应通道. 通过对反应过程中部分驻点的电子密度拓扑分析, 首次发现了接近平面的四元环状过渡态, 从而拓展了原来对环状结构过渡态定义的适用范围.     

壳聚糖接枝丙烯酸制备高强吸水材料

甲壳素（Chitin）年产量约为10-100亿吨,是仅次于纤维素（约为100亿吨）的第二大天然资源。开发利用这一自然资源宝库,具有十分重要的意义。甲壳素的脱乙酰化产物称为壳聚糖（Chitosan）。本工作对壳聚糖进行丙烯酸接枝改性,制得对蒸馏水吸水率大于800倍、吸自来水大于500倍,吸0．9％NaCl溶液吸液率130倍的吸液保液材料,该材料具有生物降解性,无环境污染,且制备工艺简单,成本低。     

电场下偶氮苯衍生物分子顺反异构化反应机理的理论研究

本工作采用密度泛函理论(DFT)方法计算研究了不同电场强度下偶氮苯衍生物2'-对甲苯偶氮基-1,1':4,4'-三苯基- 4,4'二羧酸(TTDA)顺反异构化反应的机理. TTDA经过C—N¹=N²角度顺反异构化过程存在三种可能的异构化模式 (N=N偶氮基团中与大取代基相连的N原子称为N², 与小取代基相连的N原子称为N¹), 绕N¹或N²原子的反转和绕N¹=N²键旋转. 计算结果表明, 加入沿z轴的电场(以三联苯侧链C¹→C²方向为z轴正方向), 旋转路径为反应最优路径. 此外, 还研究了沿N=N键方向加入电场(以N²→N¹方向为z轴正方向), 在电场强度F_z=0.00 V•Å^-1时, N1反转路径能垒较N2反转路径高. 当–0.62 V•Å^-1<F_z≤0.93 V•Å^-1时, 旋转路径为优势路径. 当加入沿z轴的反向电场–0.93 V•Å^-1≤F_z≤–0.62 V•Å^-1时, N2反转为优势路径.