光催化剂TiO2的改性研究进展

光催化剂TiO2在环境污染治理领域呈现出广阔的应用前景,但由于其自身存在不能响应可见光和量子效率低的缺陷而限制了它的应用,改性是提高TiO2光催化性能的重要手段。在总结国内外科研成果的基础上,综述了现阶段TiO2的主要改性方法（如光敏化、离子掺杂、复合半导体等）研究进展,并对TiO2改性方法的发展趋势进行了展望。     

长春七中异欧前胡素的提取方法研究

用80%乙醇回流提取长春七中的异欧前胡素,考察不同溶剂、不同提取方式对异欧前胡素提取率的影响,用反相高效液相色谱法测定异欧前胡素的含量。结果表明,适宜的实验条件为:用7倍量80%乙醇回流提取3次,每次1 h。在此条件下,可以获得较高的异欧前胡素提取率。     

注塑件残余应力数值模拟分析及工艺优化

基于Moldflow软件模拟研究了注塑件厚度方向上残余应力分布规律,采用正交实验设计考察了熔体温度、模具温度、注射时间和保压压力等工艺参数对注塑件平面上残余应力均值和极差的影响。结果表明,注塑件厚度方向残余应力表现出拉-压-拉的三区域分布,平面上残余应力均值和极差受保压压力影响最大,其次为注射时间和熔体温度,模具温度影响最小。最佳注射工艺组合的数值计算和试验结果比较发现,残余应力变化趋势相似,对于生产实际有重要的指导意义。     

铁屑/ZSM-5分子筛联合处理染料废水的试验研究

以四丙基溴化铵(TPABr)为模板剂合成ZSM-5分子筛并采用XRD、SEM进行了表征,研究ZSM-5分子筛、铁屑和铁屑/ZSM-5分子筛对染料废水的处理效果,分别考察了染料废水浓度、pH、反应时间、ZSM-5分子筛和铁屑投加量对活性艳兰KN-R染料废水脱色的影响.研究结果表明:铁屑/ZSM-5分子筛联合处理染料废水的效果优于单独使用铁屑和ZSM-5分子筛;在铁屑投加量50 g/L,ZSM-5分子筛投加量为4 g/L,pH值为6,反应60 min条件下,活性艳兰染料废水的脱色率可达到99.05％.     

Enhancement Factor for Gas Absorption in a Finite Liquid Layer. Part 1: Instantaneous Reaction in a Liquid in Plug Flow

An approximate analysis of gas absorption with instantaneous reaction in a liquid layer of finite thickness in plug flow is presented. An approximate solution to the enhancement factor for the case of unequal diffusivities between the dissolved gas and the liquid reactant has been derived and validated by numerical simulation. Depending on the diffusivity ratio of the liquid reactant to the dissolved gas (γ), the enhancement factor tends to be either lower or higher than the prediction of the classical enhancement factor equation based on the penetration theory (E_i,pen) at Fourier numbers typically larger than 0.1. An empirical correlation valid for all Fourier numbers is proposed to allow a quick estimation of the enhancement factor, which describes the prediction of the approximate solution and the simulation data with a relative error below 5 % under the investigated conditions (γ = 0.3–4, E_i,pen = 2–1000).     

Hydrogenation of dimethyl oxalate to ethylene glycol on a Cu/SiO2/cordierite monolithic catalyst: Enhanced internal mass transfer and stability

The design and application of a Cu/SiO₂‐based monolithic catalyst for hydrogenation of dimethyl oxalate (DMO) to ethylene glycol (EG) is presented. The catalyst was dip‐coated on cordierite with highly dispersed Cu/SiO₂ slurry prepared by ammonia evaporation method. This structure guarantees high dispersion of copper species within the mesopores of silica matrix in the form of copper phyllosilicate. The catalyst is low cost, stable, and exhibits high activity in the reaction of hydrogenation of DMO, achieving a 100% conversion of DMO and more than 95% selectivity to EG. Notably, STY_EG over the monolith is significantly enhanced compared to the packed bed Cu/SiO₂ catalysts in both forms of pellet and cylinder. It is primarily due to the relatively short diffusive pathway of the thin wash‐coat layer and high efficiency of the active phase derived from the monolithic catalyst. Theoretical results indicated that the internal mass transfer is dominated on the catalysts of pellet and cylinders. Moreover, the monolithic catalyst possessed excellent thermal stability compared to the pellet catalyst, which is attributed to the regular channel structure, uniform distribution of flow. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

IBN partition between st monomer/polymer and water and its application in miniemulsion polymerization initiated by AIBN

Isobutyronitrile has been selected as a stable substitute for the 2‐cyano‐2‐propyl radical originating from 2,2′‐azobis(isobutyronitrile) to study the behavior of this radical in miniemulsion polymerization. The partition of isobutyronitrile between styrene monomers/polymers and water has been investigated by carrying out equilibrium experiments under different conditions. Prediction based on a published kinetic model using the newly measured partition coefficient has also been compared with published experimental data and prediction based on the partition coefficient of 2,2′‐azobis(isobutyronitrile). The partition coefficients for isobutyronitrile were found to be 10.98 for the styrene/water system and 4.34 for the polystyrene/water system, respectively. The partition coefficient was found to be unaffected by selected conditions. The model prediction based on the partition coefficient of isobutyronitrile agreed well with the published experimental data, thus, indicating that the partition coefficient of the primary radical should be used in theoretical calculations rather than that of the initiator. © 2011 American Institute of Chemical Engineers AIChE J, 58: 3135–3143, 2012     

Homogeneous catalytic hydrogenation of hydroxyl‐terminated liquid nitrile rubber

It was difficult to obtain high degree of hydrogenation of hydroxyl‐terminated liquid nitrile rubber (HTBN) by using homogeneous noble metal catalyst because the hydroxyl (? OH) in HTBN was likely to cause catalyst poisoning. In this study, with hexamethyl disilylamine protecting ? OH, a good yields of hydrogenated HTBN was synthesized through the use of homogeneous metal catalyst. The effects of catalyst concentration, reaction time, hydrogen pressure, and temperature on the hydrogenation of HTBN were investigated and obtained the following optimum process parameter values: catalyst mass fraction of 0.8%, reaction time of 8 h, pressure of 1.6 MPa, and temperature of 100°C. Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy were used to characterize the hydrogenation product of the protected HTBN, indicating that under certain conditions a high degree of hydrogenation of HTBN can be achieved. Only the carbon–carbon double bonds (C?C), not the ? CN bonds, are subject to hydrogenation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

纳米载银沸石抗菌剂/聚丙烯复合材料研究

纳米载银沸石抗菌剂表面有机化修饰后,通过熔融共混法将其添加到聚丙烯(PP)中,制得纳米载银沸石抗菌剂/PP复合材料。红外吸收光谱(FTIR)和X线衍射图谱(XRD)表明,纳米载银沸石成功地接枝到PP中,但其晶体结构没有改变;热重(TGA)显示复合材料的热失重速率明显降低,热性能有一定提高;原子力显微镜(AFM)可以看出PP中有纳米载银沸石抗菌剂的存在;抗菌实验结果证明复合材料具有良好的抗菌性能。因此纳米载银沸石抗菌剂/PP可作为一种新型抗菌医用塑料,在防止院内感染和疾病的传播中起到积极作用。     

4-烯丙氧基-2,2,6,6-四甲基哌啶的合成研究

以2,2,6,6-四甲基-4-羟基哌啶、烯丙基氯和氢氧化钠为原料催化合成4-烯丙氧基-2,2,6,6-四甲基哌啶,分别研究了反应时间、原料配比、溶剂用量和催化剂用量等条件对合成4-烯丙氧基-2,2,6,6-四甲基哌啶反应的影响,确定的最佳操作条件为:反应温度为45~54℃,反应时间5h,反应物摩尔比为:n(烯丙基氯)∶n(2,2,6,6-四甲基-4-羟基哌啶)∶n(氢氧化钠)为0.45∶0.1∶0.4,溶剂用量为10g,催化剂的用量为0.2g(2,2,6,6-四甲基-4-羟基哌啶为0.1mol),收率可达到95.43%以上,纯度为99.5%。