臭氧修饰(001)晶面TiO2纳米片及其光催化降解甲苯研究

本文系统研究了臭氧修饰对(001)主导晶面锐钛矿型TiO₂光催化剂降解甲苯性能的影响. 利用自行搭建的光催化VOCs降解装置对催化剂光降解甲苯的性能进行了测试. 通过多种表征手段,结合原位DRIFTS和DFT计算研究了臭氧表面修饰及甲苯吸附和降解机理. 结果表明,用臭氧进行表面修饰可以显著提高(001)主导晶面TiO₂光催化降解甲苯的性能. (001)晶面上丰富的5c-Ti不饱和配位是臭氧分子的吸附位点,其解离后形成的Ti-O键与H₂O分子结合,在表面生成大量孤立的Ti_5c-OH. Ti_5c-OH 是甲苯分子的吸附位,它的形成显著提高了对甲苯分子的吸附能力. 在光照下Ti_5c-OH与光生空穴结合能形成·OH自由基. 通过臭氧解离产生的O₂也可以与光生电子结合形成超氧自由基. 这些具有强氧化性活性自由基的形成促进了对气相甲苯的光催化降解速率.     

乳液体系中影响分散相粒子大小及分布的因素——cmcO及cmcW的协同作用

用马尔文MastersizerMicroplus型激光粒度仪对液体石蜡及环氧树脂E-20与甲苯等有机溶剂以不同比例所形成的体系经乳化后的粒子大小及分布进行研究,结果表明,随着油溶性表面活性剂在油相中溶解性的改善,分散相的粒子大小及分布也明显得到改善.cmcO及cmcW的协同作用对获得理想的分散相粒子大小及分布起到了至关重要的作用     

负载型LaNi5合金催化剂的制备及甲苯加氢性能的研究

采用燃烧还原法制备了LaNi5合金单体,并通过球磨法将其负载到介孔分子筛MCM-41上．利用XRD,TEM对催化剂的晶相结构和形貌进行分析．结果表明,负载后的LaNi5颗粒粒径明显减小,粒径为几个到几十个纳米,制得了负载型纳米LaNi5催化剂．通过甲苯加氢反应测试催化剂的催化性能,结果表明,负载后的LaNi5催化剂催化活性比LaNi5单体有较大的提高,合金含量为40％时达到最大转化率．     

Quaternary (liquid + liquid) equilibrium data for the extraction of toluene from alkanes using the ionic liquid [EMim][MSO4]

(Liquid + liquid) equilibrium (LLE) studies for the extraction of aromatics from alkanes present in the petroleum fractions are important to develop theoretical/semiempirical (liquid + liquid) equilibrium models, which are used in the design of extraction processes. In this work, the ionic liquid 1-ethyl-3-methylimidazolium methylsulfate, [EMim][MSO₄], was evaluated as potential solvent for the separation of toluene from heptane and cyclohexane. The LLE data for the quaternary system {heptane (1) + cyclohexane (2) + toluene (3) + [EMim][MSO₄] (4)} were experimentally determined at T = 298.15 K and atmospheric pressure. Moreover, the LLE data for the ternary systems {heptane or cyclohexane (1) + toluene (2) + [EMim][MSO₄] (3)} were also determined. Solute distribution ratios and selectivities were calculated and analysed in order to evaluate the capability of the ionic liquid to accomplish the separation target. A comparison between the solute distribution ratios and selectivities for the quaternary and the ternary systems was also made. Finally, the experimental tie-line data were correlated with the NRTL model.     

甲苯的激光拉曼光谱研究

采用激光拉曼光谱技术获得了甲苯的振动拉曼光谱,结合群论方法及退偏度测量,指认了其中16条振动谱线,为有机混合物中对甲苯的识别提供了依据．选择甲苯全对称环呼吸振动（1008.8cm－1）为检测谱线,对不同浓度的甲苯／四氯化碳样品进行了分析．研究结果表明：在200．1～2．61g／L浓度范围内,甲苯／四氯化碳振动拉曼光谱强度比与甲苯浓度呈良好的线性关系,线性相关系数为0.997．为甲苯的定量分析提供了一种有效的研究方法．     

Multi-component reactions between 2-aminopyrimidine, aldehydes and isonitriles: the use of a nonpolar solvent suppresses formation of multiple products

A reliable and convenient protocol for MCRs between 2-aminopyrimidine, aldehydes and isonitriles is described. Toluene was chosen as the reaction solvent based on mechanistic reasoning. The product mixtures were found to contain a single imidazo[1,2-a]pyrimidine product in each case, which were isolated and purified by precipitation and crystallization. Chromatographic recovery from filtrates raised the total yields to 49-66%. The procedure provides a practical alternative to hitherto reported methods in which formation of multiple products was observed.     

Solubility of polycyclic aromatics in binary solvent mixtures using activity coefficient models

Polycyclic aromatic hydrocarbons (PAHs) precipitation is one of the major problems in the hydrocracking units. In this investigation, pyrene and phenanthrene were selected because they were found to be in higher concentrations in the feed to hydrocracking units. Their solubilities were investigated in toluene solvent mixture of iso-octane and heptane over a temperature range from 293 to 323 K. The experimental solubility data were used to predict the interaction parameters for seven different solid–liquid equilibrium models. The following activity coefficient models were used; Wilson, NIBS/Redlich–Kister, UNIQUAC, modified UNIFAC, modified UNIFAC (Dortmund), Flory–Huggins and Sheng. The interaction parameters were expressed as a second-order polynomial function in temperature. In order to test the models, the average absolute deviation percentage (AADP) was used. The overall AADP was found to range from approximately 7 to 14%. The models can be arranged according to their accuracy in a descending order based on AADP as follows: NIBS/Redlich–Kister, Wilson, UNIQUAC, Sheng, Flory–Huggins, modified UNIFAC (Dortmund) and finally modified UNIFAC. All models used in this work gave reasonable results; however, the group contribution models can also be used as a predictive tool for the solubility measurement of pyrene and phenanthrene in other solvents containing the same groups of the solvents used in this study.     

Excess molar enthalpies of binary mixtures of 1-hexene with some cyclic and aromatic hydrocarbons at 298.15 K

Microcalorimetric measurements of excess molar enthalpies, at 298.15 K, are reported for the four binary systems formed by mixing 1-hexene with the cycloalkanes: cyclohexane and methylcyclohexane, and with the aromatic hydrocarcons: benzene and toluene. Smooth Redlich-Kister representations of the results are presented. It was found that the Liebermann-Fried model also provided good representations of the results.     

THE ADSORPTION BEHAVIORS OF TOLUENE ON HYPERCROSSLINKED RESINS

1. INTRODUCTION Toluene has been widely used for many industrial purposes. Owing to their toxicity and recalcitrance, the presence of toluene in the natural environment, especially in the groundwater, has been a great concern. The removal of toluene is of…     

Contribution of UV light to the decomposition of toluene in dielectric barrier discharge plasma/photocatalysis system

The contribution of UV light from plasma and an external UV lamp to the decomposition of toluene in a dielectric barrier discharge (DBD) plasma/UV system, as well as in a plasma/photocatalysis system was investigated. It was found that UV light from the DBD reactor was very weak. Its contribution to the removal of toluene in the plasma/photocatalysis system could be ignored. Whereas, the introduction of external UV light to the plasma significantly improves the removal efficiency of toluene by 20%. The removal efficiency of toluene in the plasma/photocatalysis system increased about 22% and 16% when compared with a plasma only system and plasma driven photocatalyst system, respectively. The increased toluene removal efficiency was mostly attributed to the contribution of the synergy between plasma and UV light, but not to the synergy between plasma and photocatalysis. The synergetic effect between plasma and photocatalysis was not significant.