纳米金催化剂的抗水性能和抗硫中毒性能

与Au/Al2O3相比,复合载体负载的Au/FeOx/Al2O3具有更高的催化CO氧化的低温活性和稳定性,且表现出湿度增强效果,水分压为550~1 600 Pa时催化剂活性较高.在完全无水的环境中,催化剂发生快速不可逆失活;在饱和水汽的环境中,催化剂发生缓慢可逆失活.在水汽作用下的失活与纳米金粒子的粒径长大有关.助剂对催化剂抗水性能影响不大,但对抗硫中毒性能的影响较大.Au/CeO2/Al2O3催化剂显示有最佳的抗硫中毒性能.催化剂表面硫化物和硫酸盐的生成是导致催化剂不可逆硫中毒失活的主要原因.     

吸光度比值分光光度法测定复方氯唑沙宗片中氯唑沙宗和对乙酰氨基酚

根据吸光度比-光谱曲线,选定215.7 nm及264.1 nm作为测定氯唑沙宗(CRXZ)和对乙酰氨基酚(ACAP)的波长对。制备标准曲线时,首先配制由CRZX和ACAP基准物配制的标准溶液和由两者配成的混合标准系列,并在上述两波长处分别测得各试液的吸光度,再用文中提供的公式计算吸光度比值R和吸光度之差ΔR,最后建立ΔR对CRZX或ACAP浓度之间的线性回归方程。分析试样时,取复方氯唑沙宗片适量溶于溶剂中并定量稀释。分取部分试液按制备标准曲线的方法测得试液的吸光度并计算其比值R和ΔR。根据相应回归方程计算相应组分的含量。精密度及回收率试验所得结果的RSD(n=7)值为1.28%(CRXZ)及0.84%(ACAP),两者的平均回收率均为100.0%。     

CuCrAl和CuCrZr低温液相合成甲醇催化剂的研究

 用络合共沉淀法制备了CuCrAl和CuCrZr复合氧化物液相合成甲醇催化剂，其比表面分别达到119和116m2／g．在5．0～5．5MPa和383K条件下，分别用间歇式和流动式反应釜考察了催化剂的活性和稳定性．结果表明：CuCrAl和CuCrZr的活性均明显高于CuCr；CuCrAl的活性略高于CuCrZr，但甲酸甲酯（MF）的选择性明显低于CuCrZr；两者在12h内未见活性明显下降．甲醇钠在反应过程中部分转化为甲酸钠和NaOH．CuCrAl和CuCrZr有较高的氢解活性可抑制甲醇钠与MF生成甲酸钠，从而有较低的甲酸钠浓度．但是，Al2O3和ZrO2的酸性有利于甲醇脱水，引起甲醇钠水解生成NaOH．溶剂对CuCr基催化剂的活性和选择性有明显影响．对反应机理进行了讨论．     

导电复合材料葡萄糖氧化酶传感器的研究

报导了用乙基纤维素和乙炔黑获得的导电复合材料构成的葡萄糖氧化酶生物传感器的制备方法.讨论了多种因素对该生物传感器响应电流的影响.测得此电极酶催化反应的活化能为40.3 kJ•mol－1. AFM实验表明，用环己烷洗去石蜡的导电复合材料 葡萄糖氧化酶生物传感器具有粒状结构，这有利于酶催化反应的进行.     

两个新的苯并噻唑衍生物的合成与光物理性质

以苯并噻唑、苯乙酰基和吡啶阳离子为电子受体,二乙烯基苯为共轭桥,合成了两个新的A-π-A′型苯并噻唑衍生物:4-(2-苯并噻唑)-乙烯基查尔酮(1)和4-{4-[2-(苯并噻唑)乙烯基]苯乙烯基}-N-甲基吡啶碘盐(2).研究了它们在溶液和固体基质中的光物理性质.研究发现:染料2由于具有较强的极性和较好的平面性,从而具有较长的吸收、发射峰和较强的荧光发射.有机染料在聚甲基丙烯酸甲酯/溶胶-凝胶复合玻璃中的发光行为与聚甲基丙烯酸甲酯和溶胶-凝胶玻璃二者的基质性质有关,同时由于固体基质中分子发生聚集的可能性降低,荧光强度相对于同浓度溶液增强,稳定性提高.     

A Novel High Active TiO2/AC Composite Photocatalyst Prepared by Acid Catalyzed Hydrothermal Method

A high active novel TiO2/AC composite photocatalyst was prepared and used for phenol degradation. It was much more active than P-25 and exhibiting good decantability, less deactivation after several runs and less sensitive to pH change. Diffuse reflectance spectra (DRS) revealed that the electronic change in TiO2 did not occur by the addition of AC. Results of SEM and XRD suggested that better TiO2 distribution can be achieved when optimal AC content was adopted. The performance of the prepared TiO2/5AC catalyst revealed great practical potential in wastewater treatment field.     

制备方法对负载型纳米ZrO2/Al2O3复合载体性能的影响

采用浸渍-沉淀法制备了负载型纳米ZrO2/Al2O3复合载体.采用X射线衍射、N2物理吸附、差示扫描量热(DSC)和程序升温脱附等技术考察了浸渍方式和干燥方法对复合载体的表面性能、热稳定性和晶相结构的影响.结果表明,ZrO2/Al2O3复合载体中没有生成ZrO2-Al2O3复合氧化物或固溶体,纳米ZrO2仅负载在Al2O3的表面.微波干燥法制备的ZrO2/Al2O3复合载体的比表面积(158.7 m2/g)较大,最可几孔径为19.4 nm,ZrO2的粒度为4.2 nm,晶相结构为四方相ZrO2.微波诱导作用使ZrO2/Al2O3复合载体表面产生了新的酸碱中心,微波干燥法制备的ZrO2/Al2O3复合载体具有较强的热稳定性,在873~1 073 K范围内DSC曲线没有出现吸热峰,而其它干燥方法制备的复合载体在903~1 023 K范围内出现了较明显的吸热峰,表明复合载体表面的部分四方相ZrO2转变为单斜相ZrO2(m-ZrO2).对超声波处理过的复合载体进行微波干燥能进一步提高纳米ZrO2与Al2O3之间的相互作用,纳米粒子的粒度(3.4 nm)更小,分布更均匀,但没有改变ZrO2的晶相结构.     

Sorption of carbon dioxide by the composite sorbent “potassium carbonate in porous matrix”

Sorption of CO₂ in the presence of water vapor by the K₂CO₃—-Al₂O₃ composite sorbent was studied by IR spectroscopy in situ, X-ray diffraction analysis, and the differentiating dissolution method and reasons for a decrease in its dynamic capacity are given. The samples containing K₂CO₃·1.5H₂O in pores are characterized by the maximal dynamic capacity. A mechanism for CO₂ sorption was proposed, which qualitatively explains the obtained dependence of the capacity on the water content in the composite sorbent. A high dynamic capacity can be maintained by regeneration of the sorbents by water vapor at 170 °N. The capacity of the sorbents decreases during the first 10 sorption—regeneration cycles due to the formation of an inactive phase of potassium aluminum carbonate.     

Production of micron-sized monodispersed composite polymer particles by seeded polymerization utilizing the dynamic swelling method

 In order to develop the seeded polymerization technique utilizing the dynamic swelling method (DSM) proposed by authors for the production of micron-sized mono-dispersed “composite” polymer particles consisting of two kinds of polymers, the seeded polymerization for the dispersion of ethyl methacry-late (EMA)-swollen PS particles prepared utilizing DSM was carried out. Monodispersed PS/poly(ethyl methacrylate) (PEMA) composite particles having 7 μm in diameter were produced by the addition of NaCl to lower the solubility of EMA in medium and by the addition of CuCl₂ as a water-soluble inhibitor to depress the by-production of submicron-sized PEMA particles. Received: 16 July 1996 Accepted: 10 October 1996     

Determination of Low Contents of Fenpiverine Bromide by Extraction Spectrophotometry

An ion-pair extraction spectrophotometry method was developed for the determination of fenpiverine bromide in tablets. To determine this substance it was necessary to find experimental conditions that would allow eliminating the influence of other components of the tablets. Attention was paid to the fact that a suitable pH of water phase was necessary to achieve high selectivity.Received December 11, 2002; accepted April 24, 2003 Published online July 28, 2003