新型自组装纳米胶团人工过氧化物酶研究

十二烷基肌氨酸钠与天然细胞色素c通过自组装方式构建了一种新型纳米胶团结构人工过氧化物酶(Artificial Peroxidase,AP)。采用紫外可见光分光光度计对AP酶促反应过程进行研究。表明AP在较宽的pH范围具有活性,并在pH 5.0,100 mmol/L磷酸盐缓冲液中达到最大。该AP的米氏常数Km、催化速率kcat以及催化效率分别为1.70μmol/L、0.11 s-1、0.065μM-1s-1,催化效率为天然辣根过氧化物酶的90.2%。     

疏水缔合型阳离子聚丙烯酰胺的合成及絮凝性能

以甲基丙烯酸三氟乙酯(TFEMA)为疏水单体、丙烯酰胺(AM)为主单体、甲基丙烯酰氧乙基三甲基氯化铵(DMC)为阳离子单体,以过硫酸铵和亚硫酸氢钠为复合引发剂,采用自由基胶束聚合法合成了共聚物P(AM-DMC-TFEMA)。分别考察了反应温度、引发剂用量、单体总质量分数及反应时间对P(AM-DMC-TFEMA)的产率及阳离子度的影响。确定较佳工艺条件为:反应温度65℃,引发剂用量占单体总质量的2%,单体总质量分数26%,反应时间3 h。采用红外光谱(FT-IR)、核磁共振氢谱(~1H NMR)和环境扫描电镜(ESEM)对其结构进行了表征。同时考察了P(AM-DMCTFEMA)对硅藻土悬浮液的絮凝效果,结果表明,其对硅藻土具有良好的絮凝效果,絮凝时间仅为20 s,合成的共聚物上清液透过率为97.31%。     

一种疏水缔合丙烯酰胺共聚物的合成及流变性能评价

采用自由基胶束共聚法以丙烯酰胺(AM)和N-苄基-N-辛基丙烯酰胺(BOAM)为原料,合成了疏水缔合共聚物(AM-NaA-BOAM),并用红外光谱(FT-IR)和核磁共振(1H-NMR)表征了共聚物的结构.溶液的流变性实验表明,当共聚物浓度大于600 mg/L时,表现黏度显著增大,表现出疏水缔合行为,溶液的储能模量(G...     

耐高温FRK-VES清洁压裂液性能评价

针对国内外清洁压裂液耐温性能较差的问题,开发出一种新型的两性离子表面活性剂压裂液体系。该清洁压裂液体系优化配方为4.0%FRK-VES＋0.30%稀盐酸＋4.0%KCl溶液＋1.0%苯甲酸钠。室内实验对FRK-VES压裂液体系性能进行了评价：耐温耐剪切性良好,120℃的表观黏度为83 mPa.s（170 1/s）,30℃连续剪切60 min的黏度为3167 mPa.s;携砂性能良好,摩阻较小,在常温下与原油和地层水混合可迅速破胶,破胶液黏度小于5 mPa.s,并且无残渣,破胶液界面张力为0.75 mN/m,表面张力为24.8 mN/m;该体系滤失系数为1.93×10-4m/min1/2,对渗透率为1μm2和0.2μm2储层的渗透率伤害率分别为19.56%、25.36%,适合不超过120℃的高温低渗砂岩的储层改造。该清洁压裂液在胜利油田、华北分公司现场施工,效果较好。图3表5参11     

Hydrophobically modified poly(sodium 2‐acrylamido‐2‐methylpropanesulfonate): synthesis and viscosity of aqueous solution

BACKGROUND: Hydrophobically modified polyelectrolytes are widely used polymers due to their good water solubility, stretched configuration in water and strong hydrophobic association. The study reported here aimed at researching the double action of hydrophobic association and electrostatic effect of novel hydrophobically modified polyelectrolytes in solution. RESULTS: A series of novel hydrophobically modified polyelectrolytes were synthesized by micellar copolymerization with various feed ratios of sodium 2‐acrylamido‐2‐methylpropanesulfonate, N‐n‐dodecylamine and sodium dodecylsulfonate. Their structure was characterized using Fourier transform infrared spectroscopy, nuclear magnetic resonance and gel permeation chromatography, and the viscosities of their aqueous and salt solutions were studied. CONCLUSION: The results show that the addition of the hydrophobic comonomer results in a decrease in molecular weight (M_w). The smaller the initial number of hydrophobes in one micelle, the higher is M_w of the resulting copolymer. The viscosity of PAD‐1.73 polyelectrolyte is less sensitive to salt than those of the others. According to the zero shear viscosity and corresponding concentration, the critical cluster‐forming concentration, critical overlap concentration and critical entanglement concentration of these polymer solutions were determined. Moreover, in the dilute regime the viscosity decreases with increasing salinity, while in the semi‐dilute regime the viscosity decreases first and then increases. It is suggested that in dilute and semi‐dilute regimes, hydrophobic intramolecular association and intermolecular association dominate, respectively. Copyright © 2009 Society of Chemical Industry     

Rate acceleration of Diels–Alder reactions utilizing a fluorous micellar system in water

A fluorous micellar system in water has been created to produce a large interfacial area between these media that retains substrates, effectively facilitating intermolecular Diels–Alder reactions due to repulsion effects from both media. Because LiFOS functioned not only as a surfactant but also as a supporting electrolyte, an electrochemical approach could be introduced to evaluate the rate acceleration effects. The measurement of the particle size distribution of the fluorous micelles clearly supported these evaluations.     

Micellar Enhanced Ultrafiltration as a Method of Removal of Chromium(III) Ions from Aqueous Solutions

This study was undertaken to check the possibility of using micellar enhanced ultrafiltration (MEUF) in the removal of chromium(III) ions from water systems. The influence of ion concentration in the feed, type of surfactant (SDS or Rofam 10), and the membrane material on separation efficiency were studied and discussed. The use of environmentally safer surfactants from renewable sources was proposed, that is, oxyethylated rape fatty acid methyl esters – trade name: Rofam 10. The results presented show the possibility of using MEUF as an effective method for removing chromium(III) ions from aqueous solutions, especially from solutions of low concentration.     

孪尾疏水缔合水溶性聚合物P(AM/NaAA/DiC_8AM)水溶液的黏度行为

研究了胶束共聚法制备的孪尾疏水缔合水溶性聚合物P(AM/NaAA/D iC8AM)的水溶液的黏度行为。当疏水单元摩尔分数为0.05%~0.40%时,P(AM/NaAA/D iC8AM)在30℃、c(NaC l)=1.000 mol/L水溶液中的特性黏数[η]为2 149~367 mL/g、Huggins常数KH为0.220~3.90;随疏水单元摩尔分数增加,特性黏数[η]减少、KH增加。在矿化度为19 334μg/g的盐水溶液中,P(AM/NaAA/D iC8AM)的表观黏度随疏水单元摩尔分数的增加而增加、随剪切速率的增加而降低。随疏水单元摩尔分数的增加,临界缔合质量浓度降低;与后加的SDS[ρ(SDS)=0~6.0 g/mL]的疏水缔合作用增强,黏度增加的幅度增大。表观黏度随温度的变化也与疏水单元摩尔分数有关,当x(H)=0.3%、温度升至45℃左右时,出现最大值。在NaC l、CaC l2的离子强度分别为1.26×10-3~4.88×10-3mol/kg、1.07×10-4~5.28×10-4mol/kg的水溶液中,出现盐增黏现象。     

Construction and Properties of Hydrophobic Association Hydrogels with High Mechanical Strength and Reforming Capability

Hydrophobic association hydrogels (HA‐gels) with almost ideal properties were successfully prepared by micellar copolymerization, and the associated micelles acted as physical cross‐linking points in the network of HA‐gels. HA‐gels exhibit exceptional mechanical properties and transparency. However, the most striking properties are that HA‐gels possess the capability of self‐healing and remolding, which is mainly due to the dissociation and re‐association process of the associated micelles. Dried‐gels, which were prepared by stretching HA‐gels to a certain elongation for a period of time in the air, can be used as shrinkable or thermal sensitivity materials. HA‐gels have a broad selectivity for components, so we have synthesized HA‐gels with variously available properties by changing a corresponding component: thermoresponsive HA‐gels, nanosphere‐composite HA‐gels, and fluorescent HA‐gels. Therefore, we are sure that HA‐gels will be widely used in various fields, such as biology, medication, sensors, optics, and oil exploitation.

     

光化学反应中的磁场效应 Ⅱ.电子转移光敏化1,2-二苯乙烯的顺反异构化反应

前文报道了外加磁场对吸附在硅胶表面上的芳砜光解反应的影响,本文报道外加磁场影响光化学反应的另一个例子——电子转移光敏化1,2-二苯乙烯的异构化。 近年来电子转移光敏化反应引起了有机光化学家们的极大注意。一些异构化、重排、裂解、氧化反应都可以通过电子转移机理敏化。电子转移光敏化的机理可以用(1)描述。图中A和D分别代表电子的受体和给体。