季铵化N,O-(2-羧乙基)壳聚糖的制备及其抑菌性能

以缩水甘油基三甲基氯化铵(GTMA)、缩水甘油基三乙基氯化铵(GTEA)、缩水甘油基三丙基氯化铵(GTPA)、缩水甘油基三丁基氯化铵(GTBA)和缩水甘油基二甲基苄基氯化铵(GDMBA)等活性季铵盐为季铵化试剂,对N,O-2-羧乙基壳聚糖(N,O-2-CEC)进行了化学改性,得到了系列季铵化N,O-2-CEC(QCEC...     

壳聚糖季铵盐改性石墨烯的制备及电化学性能研究

采用2-羟丙基三甲基氯化铵壳聚糖(HACC)通过非共价作用修饰氧化石墨烯,然后通过水合肼还原得到HACC改性的石墨烯(HACC-RGO).采用红外光谱、X射线衍射和场发射扫描电子显微镜对改性石墨烯进行结构和形貌的表征.通过热重测试分析HACC在改性石墨烯中的实际含量.分析对比不同改性石墨烯的zeta电位值,并通过动态光散射粒径仪研究HACC-RGO在不同p H值溶剂中的分散性及粒径大小.结果表明,HACC成功结合到石墨烯表面上并插入石墨烯片层间,得到的HACC-RGO在p H为2~9的水溶液中均能稳定分散,在水溶液p H值为7时分散粒径最小.随着HACC用量的增大,HACC在HACC-RGO中的含量增加,HACC-RGO在水中的zeta电位值也相应增加,而HACC-RGO的平均粒径却减小.通过循环伏安法研究HACCRGO的电化学性能,结果表明HACC-RGO具有较好的导电性,铁氰化钾在HACC-RGO/GCE上的还原峰电流随着HACC用量的增加而增大,氧化还原峰电流随着还原剂水合肼用量的减少而降低.     

阳离子改性壳聚糖的合成工艺

弱碱性条件下,在壳聚糖（CTS）上引入2-羟丙基三甲基氯化铵（CTA）基团,使其阳离子化。采用正交试验通过测定合成产物的取代度确定其最佳合成条件,再用红外光谱对产物结构进行表征。结果表明：CTS/CTA质量比=1∶5,溶胀时间60 min,碱化温度35℃,反应温度60℃,反应时间9 h为该工艺的优化条件,在此条件下合成...     

羟丙基三甲基氯化铵壳聚糖制备的可控性研究

用壳聚糖与缩水甘油三甲基氯化铵反应制备羟丙基三甲基氯化铵壳聚糖,所得产物的结构受壳聚糖分子量和脱乙酰度、反应温度、反应时间、壳聚糖与缩水甘油三甲基氯化铵投料比的影响。实验结果表明：随着反应温度升高,羟丙基三甲基氯化铵壳聚糖的取代度增加,在70～80℃达最大;反应时间增加,取代度增加,产物分子量降低。缩水甘油三甲基氯化铵与壳聚糖比例达3：1前取代度随比例升高而增加。脱乙酰度和分子量越大的壳聚糖其季铵盐取代度越高。控制反应温度在30～90℃,反应时间3～10h,投抖比为1：1～4：1,可以得到取代度15％～909／6,分子量1万到100万的羟丙基三甲基氯化铵壳聚糖。     

新型两性聚电解质高吸水性树脂CMCTS-g-（PAA-co-PTMAAC）的制备研究

通过氧化还原引发荆引发的接枝共聚反应,使阴离子型单体丙烯酸(AA)和阳离子型单体三甲基烯丙基氯化铵(TMAAC)在羧甲基壳聚糖(CMCTS)的分子链上接枝共聚,制得羧甲基壳聚糖接枝-(聚丙烯酸-co-聚三甲基烯丙基氯化铵)(CMCTS-g-(PAA-co-PTMAAC)两性聚电解质高吸水性树脂.采用红外光谱对产物的结构进行了表征,比较了反应条件对产物吸液性能的影响.发现制备具有良好吸液性能的高吸水性树脂的最优化反应条件为:TMAAC占单体总质量的14.3%,mNNMBA/mAA值在0.014附近,单体总质量为CMCTS质量的9.33倍,丙烯酸中和度在20%～30%之间.研究发现,随外部溶液pH值的变化,两性聚电解质高吸水性树脂的溶胀性能在酸性和碱性条件下各有一个最大值,在等电点处产物的吸液性相对较低.     

壳聚糖季铵盐-Zn(Ⅱ)催化磷酸双酯与质粒DNA水解动力学

采用壳聚糖与缩水甘油三甲基氯化铵反应制备了壳聚糖季铵盐(HTACC), 研究了其Zn(Ⅱ)配合物HTACC-Zn(Ⅱ)催化DNA的模拟底物对硝基苯酚磷酸双酯(BNPP)水解的动力学过程及其对质粒DNA的催化裂解. 结果表明, HTACC-Zn(Ⅱ)对BNPP的水解反应具有良好的催化活性, 其表观一级速率常数可达到6.7×10-6 s-1, 为BNPP自发水解时的6.0×104倍; 同时, HTACC-Zn(Ⅱ)还能够有效催化质粒DNA(pUC19)的裂解, 使DNA分子由超螺旋结构裂解为开环和线型结构.     

高取代度羧甲基壳聚糖的制备

用非质子溶剂法,以DMSO-H2O为溶剂,在碱性条件下壳聚糖(CTS)与氯乙酸反应,制得取代度为1.93的羧甲基壳聚糖(CMC)。较适宜的反应条件为:CTS 1 g,m(氯乙酸)∶m(CTS)=5∶1,w(NaOH)=35%(以CTS质量计算),w(十六烷基三甲基溴化铵)=5%(以CTS质量计算),于50℃反应6 h。用XRD和IR对CMC进行表征,结果表明CTS的-OH参与了羧甲基化反应,-NH2没有参与反应。     

CTA季铵化壳聚糖合成条件的优化及其结构表征

以3-氯-2-羟丙基三甲基氯化铵(CTA)为改性剂,在碱性条件下制备了水溶性壳聚糖季铵盐,并以该产物对Cr2O7^2-的絮凝去除率为基准优化了合成条件,用IR和^1H-NMR表征了产物结构。结果表明,优化的合成条件为：反应时间为10．0h,温度为65．0℃,mNaOH／mCTS=1．0,mCTA／mCTS=4．0。在此条件下合成的产物对Cr2O7^2-的最大去除率达94．39％,壳聚糖的季铵化反应主要发生于C2位的氨基上。     

用氯离子电极同时测定阳离子表面活性剂的CMC及反离子缔合度

临界胶束浓度(CMC)是研究表面活性剂的一个重要参数,胶束的反离子缔合度(K)是重要的特性参数。本文以阳离子表面活性剂十烷基三甲基氯化铵(DTMAC)、十二烷基三甲基氯化铵(DTAC)、十四烷基三甲基氯化铵(TTAC)、十六烷基三甲基氯化铵(CTAC)和十八烷基三甲基氯化铵(OTAC)水溶液体系为研究对象,用氯离子选择电极分别测定了其水溶液体系胶束的CMC和K。     

壳聚糖预分离富集-离子色谱法测定痕量草酸根

本文通过壳聚糖(CTS)对水样中草酸根的预富集,利用离子色谱作为检测手段,建立了测定痕量草酸根的新方法。研究了CTS对C2O42-的吸附行为,考察了吸附时间、CTS用量、共存离子等对吸附率的影响。结果表明:在pH=3.0时,CTS对C2O42-的吸附率最大,可达100%;吸附后的C2O42-用0.1 mol/L的NaOH即可定量解吸,解吸率为96%;C2O42-的检出限为4.3μg/L,相对标准偏差(RSD)为7%(n=6)。CTS对C2O42-的等温吸附特性符合Langmuir方程,其饱和吸附量为194.0 mg/g。本方法用于水样中C2O42-的测定,结果满意。     

羟丙基三甲基氯化铵壳聚糖的制备及其吸湿、保湿性能

抑菌活性;羟丙基三甲基氯化铵壳聚糖的制备及其吸湿、保湿性能     

Novel 2-Hydroxypropyltrimethyl Ammonium Chitosan Derivatives: Synthesis,Characterization, Moisture Absorption and Retention Properties

Recent years have seen a steady increase in interest and demand for the use of humectants based on biodegradable natural polymers in many fields. The aim of this paper is to investigate the moisture absorption and retention properties of 2-hydroxypropyltrimethyl ammonium chitosan derivatives which were modified by anionic compounds via ion exchange. FTIR, ¹H NMR, and ¹³C NMR spectroscopy were used to demonstrate the specific structures of chitosan derivatives. The degrees of substitution for objective products were calculated by the integral ratio of hydrogen atoms according to ¹H NMR spectroscopy. Meanwhile, moisture absorption of specimens was assayed in a desiccator at different relative humidity (RH: 43% and 81%), and all target products exhibited enhanced moisture absorption. Furthermore, moisture retention measurement at different relative humidity (RH: 43%, 81%, and drier silica gel) was estimated, and all target products possessed obviously improved moisture retention property. Specifically, after 48 h later, the moisture retention property of HACBA at 81% RH was 372.34%, which was much higher than HA (180.04%). The present study provided a novel method to synthesize chitosan derivatives with significantly improved moisture absorption and retention properties that would serve as potential humectants in biomedical, food, medicine, and cosmetics fields.     

用红外水分测定仪快速测定食品中的水分

采用GB／T5009．3-2003和红外干燥法对3种固体食品样品分别进行水分检测,红外干燥法大大缩短了检测时间,且操作简便。经过显著性检验,红外干燥法检测结果与国标法无显著性差异。     

Study on conductance of supersaturated chloride microdroplets

By using the measuring system previously designed by the authors, the conductance of KCl, NaCl and NH₄Cl microdroplets is obtained in the whole measuring RH range, especially in the supersaturation region, which cannot be acquired from the bulk solutions and fills the gap of lack of experimental data of conductance under the supersaturated state. The ERH and DRH of these three kinds of microdroplets observed from a microscope are 80.5% and 95.4% (KCl), 75.7% and 93.3% (NaCl), and 69.9% and 96.6% (NH₄Cl), respectively. In addition, it can be found from the dependence of conductance on RH that conductance is very sensitive to the existence of water molecules inside the microdroplet and the threshold of the deliquescence process can be predicted by the variation of conductance. Supported by the National Natural Science Foundation of China (Grant Nos. 20673010 and 20605004), Fundamental Research Foundation of BIT (Grant No. 20060742003), Program of Introducing Talents of Discipline to Universities (Grant No. B07012), and China Postdoctoral Science Foundation (Grant No. 20070410467)     

CuCl2-KCl-LaCl3/γ-Al2O3对乙烷氧氯化反应的催化性能

 以γ-Al2O3为载体,采用常规浸渍法制备了负载型CuCl2-KCl-LaCl3三组分催化剂,并研究了其对乙烷氧氯化反应的催化性能. 结果表明,该催化体系中乙烷的转化率较稳定,但随着反应时间的延长,氯乙烯的选择性和收率明显下降. XRD,N2吸附,TGA/DTA和XPS测试结果表明,随着反应的进行,催化剂中的活性物种Cu2+逐渐被还原成Cu+,并且积炭的产生使催化剂的比表面积和孔容积减小. 活性物种Cu2+的减少及比表面积的降低是催化剂失活的主要原因.     

S-tosylsulfene chloride — The first representative of a new class of sulfene halides

A representative of a previously unknown class of S-sulfonylsulfene halides — S-tosylsulfene chloride (1) — was prepared for the first time. It was shown that the reaction of sulfene chloride1 with cyclohexene yieldstrans-2-chlorocyclohexyl-p-toluene thiosulfonate, and the reaction with 1-hexene yields a mixture of 2-chlorohexyl-p-toluene thiosulfonate and 1-chloro-2-hexyl-p-toluene thiosulfonate.M. V. Lomonosov Moscow State University, 119899 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 5, pp. 1217–1218, May, 1992.     

1, 5-二芳酰基环戊二烯的制备

本文报道了用二(环戊二烯基)氯化钇与芳烃酰氯反应,用DME作溶剂,在室温下生成单一产物,1,5-二芳酰基环戊二烯的新方法。     

Diverse Reactions of Sulfonyl Chlorides and Cyclic Imines

Abstract

Although alkanesulfonyl chlorides react with linear imines to give rise to β-sultam derivatives, in this study, they were reacted with various cyclic imines, including 1-pyrroline, oxazoline, 5,6-dihydro-4H-oxazines and thiazines, 4,5-dihydro-3H-benzo[c]azepine, and 3,4-dihydroisoquinoline, to produce diverse products instead of β-sultam derivatives. The results indicate that alkanesulfonyl chlorides react with cyclic imines to generate N-alkanesulfonyl cyclic iminium ions, which are attacked by nucleophiles, such as water and chloride anion, in the reaction systems, affording addition products. The iminium intermediates cannot undergo a ring closure to form β-sultam derivatives. Arenesulfonyl chlorides showed similar behavior when they reacted with cyclic imines. The scope and limitation of the reaction between sulfonyl chlorides and imines were investigated.

GRAPHICAL ABSTRACT      

混合电解质的电导测定

电导测定为研究离子与离子之间的缔合效应、离子与溶剂的相互作用及溶剂结构提供了一个有效手段 .目前 ,电解质水溶液、电解质非水溶剂体系的电导数据却很缺乏 ,而混合电解质体系的电导测定在理论及应用方面都很重要 .作为全面系统地考察金属氯化物的混合电解质的电导性质变化规律 ,前文已测定了 Na Cl- KCl- H2 O体系 [1] 、 Na Cl- Rb Cl- H2 O体系及 KCl- Rb Cl- H2 O体系的电导值 [2 ] ,本文用自行设计的电导池测定了 Ca Cl2 - H2 O,Ca Cl2 - Na Cl- H2 O,Ca Cl2 - KCl- H2 O体系在 2 98.1 5 K时的低浓度电导数据 ,探讨了…     

以氯代酰氯为试剂的聚砜膜材料的付-克酰基化反应

采用氯乙酰氯和氯丁酰氯两种ω-氯代酰氯化试剂,在Lewis酸催化剂存在下,于室温下分别对聚砜（PSF）材料实施了Friedel-Crafts酰基化反应,制备了氯代酰基化（CA）聚砜材料CAPSF。用FT-IR、1H-NMR与佛尔哈德分析法表征了该产物的化学结构与组成。结果表明：在室温（25°C）下,以CH2Cl2为溶剂...