Reaction Coupling of Ethylbenzene Dehydrogenation with Nitrobenzene Hydrogenation

The chemical equilibrium for the coupling of ethylbenzene dehydrogenation with nitrobenzene hydrogenation, to produce styrene and aniline simultaneously, has been calculated on the basis of the Soave–Redlich–Kwong equation of state. The dehydrogenation of ethylbenzene in the presence of nitrobenzene over the catalysts -Al₂O₃, ZSM-5, activated carbon and platinum supported on activated carbon has been carried out at 400 °C. The effects of Pt loading and the pretreatment of the catalysts have been investigated. It has been revealed that the conversion of ethylbenzene can be greatly improved by the reaction coupling due to the elimination of the hydrogen produced in the reaction by the hydrogenation of nitrobenzene. Platinum supported on the activated carbon has been suggested as a suitable catalyst. The best results with ethylbenzene conversion of 33.8% and styrene selectivity of 99.2% were obtained over Pt(0.02 wt%)/AC at 400 °C. Moreover, such process is also energetically favored since the necessary process heat to drive the ethylbenzene dehydrogenation can be provided by the coupling with the exothermic nitrobenzene hydrogenation reaction.     

A molecular dynamics simulation study on the crystallization of 22,8-polyurethane

By means of the molecular dynamics (MD) simulation, the crystallization mechanism of 22,8-polyurethane which contains hydrogen-bond units is investigated and the results show that the crystallization process at a fixed temperature can be characterized by three stages: (1) The extended chain collapses to a globular random coil; (2) The random coil reorganizes into an ordered lamellar structure; (3) Accompanied with the segments clustering due to the hydrogen-bond formation, the lamellar develops with local defects. Two kinds of hydrogen-bond, which are formed between NH group and CO group (N-H?OC), and between NH group and urethane alkoxy oxygen (N-H?O), respectively, are found to play an important role in the crystallization process of 22,8-polyurethane. Furthermore, the effect of temperature on the crystallization is also studied by selecting three temperatures 200, 300 and 400 K. The lower the crystal temperature is, the slower the crystallization rate is and the stronger the hydrogen-bonding interactions are presented. This is in harmony with the experimental results.     

在线分析仪表水封结构的改进

原在线分析仪表的水封工作时,存在样气串气、带尘、带液现象,造成在线分析仪器的腐蚀并影响仪表指示,致使分析结果不准确或出现故障。水封结构改进后,在线分析系统的稳定性、可靠性大为提高。     

超声波技术在污泥减量化中的应用研究现状

城市污水厂污泥处理处置已成为行业面临的一个难题。本文介绍了超声波技术在污泥减量化中的研究应用现状,重点阐述了其作用机理,超声波对污泥性质、污泥好氧消化和污泥厌氧消化的影响,最后指出了超声波技术在污泥减量化中的研究发展方向。     

利用蓄电池废硫酸和硼泥制备高品质氢氧化镁

利用废铅酸蓄电池中的废硫酸作为浸取剂,对硼泥中的镁进行回收并制备出高品质的氢氧化镁产品。实验得出了酸浸硼泥的最佳工艺条件：酸浸温度为80℃;酸浸时间为30 min;酸用量为硫酸与硼泥质量比为1.2∶1。利用不同金属水解pH的不同,将酸浸过程中从硼泥和废硫酸中引入的杂质依次去除,得到精制硫酸镁溶液。由精制硫酸镁制取氢氧化镁的工艺条件为：常温下,沉淀剂为氨水,反应终点pH为11,反应时间为2 h,反应物在50℃下陈化12 h,过滤、洗涤后105℃烘干。实验考察了不同沉淀剂对氢氧化镁形貌的影响。所得氢氧化镁纯度在97%以上,粒径在0.1～1μm之间,各项指标均优于中国化工行业标准。     

中和缓蚀剂Gibchem5911G的工业应用

叙述了中和缓蚀剂Gibchem5911G的缓蚀机理，以及缓蚀剂在中国石油大庆石化公司化工一厂裂解老区装置裂解气压缩机EC-301段间后冷器中的使用效果。通过对缓蚀剂注入前后EC-301段间后冷器中工艺凝液的pH值与总铁含量进行对比分析，可以看出该缓蚀剂可以改善压缩机段间后冷器中工艺凝液的pH值，能够有效地抑制后冷器腐蚀的发生。     

Zwitterion effect in polyelectrolyte gels based on lithium methacrylate-N,N-dimethyl acrylamide copolymer

Zwitterionic compounds such as those based on 1-butylimidazolium-3-(n-butanesulfonate) have previously been shown to have positive effects on the transport properties of polyelectrolytes. The addition of the zwitterion has been found to, in some cases, increase the dissociation of the lithium ion and enhance the conductivity by almost an order of magnitude. In this work, we report the effects of adding the above-mentioned zwitterion into the polyelectrolyte gel system poly(lithium methacrylate-co-N,N-dimethyl acrylamide); the anionic group being a stronger base leads to different behaviour for this copolymer compared to previous work. Polyelectrolyte gels based on dimethyl sulfoxide and polyether solvents were investigated to determine the breadth of applicability of the zwitterion in improving lithium ion transport. Impedance spectroscopy and pulse field gradient-NMR diffusion indicate an increase in the number of available charge carriers with zwitterion addition in some gel systems, however, the effect is not universal.     

关于大学学习分类的研究与探索

本文首先比较仔细地分析了几种具有重要影响的学习分类理论,即联想学习、奥苏贝尔意义学习、布鲁姆教育目标分类学中关于学习的分类、加涅对学习结果的五种分类等,并分析了四者之间的联系和区别,以及学习分类理论的发展趋势.在此基础上提出了大学学习的主要内涵,并据此将大学学习划分为程序性知识、陈述性知识、认知策略、动作技能、情感五类结果.     

Na0.5Bi0.5TiO3-K0.5Bi0.5TiO3系无铅压电陶瓷的制备工艺研究

利用XRD、SEM等分析技术 ,研究了Na0 .5Bi0 .5TiO3 -K0 .5Bi0 .5TiO3 系无铅压电陶瓷的合成温度 ,烧成工艺条件对陶瓷晶体结构、压电性能的影响。结果表明 ,合成温度提高有利于主晶相的形成 ,适当延长保温时间有利于材料的压电性能。该体系随着KBT含量的增加 ,烧结温度提高 ,烧结温度范围变窄。同时研究了极化工艺条件对材料压电性能的影响表明 ,提高极化电场和适当提高极化温度有利于压电性能的提高 ,但过高的温度由于受到材料高温下退极化的影响而导致材料压电性能变差     

Preparation and Catalytic Performance of Mesostructured Aluminosilicate Nano-particles with Wormhole-Like Framework Structure

A facile two-step sol–gel method has been developed for the preparation of mesostructured aluminosilicate nano-particles (Si/Al = 7.5) with wormhole-like but uniform pore structures and highly catalytic activities towards bulky hydrocarbon cracking. It is desirable that, as this synthesis takes place in the absence of alkali cations, the mesoporous nano-particulate material is directly obtained in the acid form, making a subsequent ion-exchange and calcination treatment superfluous.