共查询到20条相似文献,搜索用时 31 毫秒
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在以二甲亚砜作溶剂,以D-72固体磺酸树脂为催化剂的两相体系中,实现了由环己酮肟液相贝克曼重排制备己内酰胺的反应.主要考察了环己酮肟在固体酸催化剂上的吸附热力学规律以及溶剂、反应温度、反应时间、催化剂用量以及催化剂的重复使用性等因素对重排反应的影响.结果表明,环己酮肟在磺酸树脂上的等温吸附过程符合Langmuir吸附模型,吸附等温线可用Langmuir等温方程和速率方程来描述.在二甲亚砜溶剂中,当反应温度在130℃,催化剂用量为0.5 g(催化剂:环己酮肟=1:2(质量比))的条件下反应6小时,环己酮肟的转化率高达100%,己内酰胺的选择性为86.2%,主要副产物为环己酮.该法对环境无害,反应条件温和,催化剂容易分离和可重复使用等优点. 相似文献
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氧化钴/吸附树脂催化剂在对甲酚氧化反应中的催化性能研究 总被引:5,自引:0,他引:5
本文研究了吸附树脂D3520负载的氧化钴催化剂对甲酚氧化反应中的催化性能。结果表明:该催化剂具有良好的活性和选择性;甲醇为反应的良溶剂;D3520载体对活性组份具有良好的吸附性能,延长了催化剂的使用寿命。 相似文献
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本文以H大孔吸附树脂为母体,进行磺化反应,制得新型大孔强酸离子交换树脂,通过对这类树脂的交换量和物理结构的测定,研究了在H树脂上进行磺化反应的影响因素,同时也得到了这类强酸离子交换树脂的一些物化性能参数,为其应用提供了一定的参考数据。 相似文献
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铈基催化剂的密度泛函理论研究进展 总被引:3,自引:0,他引:3
铈基催化剂是重要的汽车尾气三元转化(TWCs)及挥发性有机废气(VOCs)氧化催化剂,从理论上系统研究载体、活性组分的性质及其相互作用,反应物在铈基催化剂上吸附与反应行为,可认识催化现象的电子本质,加深反应机制的理解,为催化剂的设计提供理论参考与依据。本文通过CeO2体相、表面、氧空位、团簇性质,探针分子在CeO2表面吸附反应行为,金属铈基催化剂性质及探针分子在其表面吸附与反应等4个方面对近年来的研究工作进行了综述,指出了铈基催化剂研究的方向与前景。 相似文献
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In the presence of Friedel-Crafts catalyst, the chloromethylated copolymer of styrene-divinylben-zene may react with each other and cross-link by itself Thus a new type of polymeric adsorbent wasobtained, and its structure was identified by its physical properties and infrared spectra. The Friedel-Crafts reaction is manifestly affected by the nature of the solvent, the kind and amount of catalystused, reaction temperature and reaction time, etc. The porous structure and physical properties of the adsorbent prepared have been investigatedsystematically. The adsorbent has high specific surface area (1000--1300m~2/g), porosity, narrowpore distribution,high skeleton density and good mechanical properties. 相似文献
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色谱流出峰的拖尾现象普遍存在于制备和大型色谱分离过程中,它直接影响分离的产率和回收率.本文提出采用色谱流出峰形的不对称偏差度来表征色谱流出峰的拖尾程度;并基于液相制备色谱分离过程FAD-SMT模型及吸附速率理论,通过计算机模拟,定量分析了吸附剂性能和操作参数对色谱流出峰形不对称性的影响。结果表明:不仅是吸附剂的热力学和动力学性能(包括吸附相平衡关系、液固两相间的传质阻力);而且柱的设计和吸附剂的装填状况(包括轴向扩散系数),以及色谱分离的操作条件(进料时间、浓度和流速等)都直接影响色谱流出峰形的不对称性。随着吸附相平衡等温线的非线性程度增大,或者总传质系数的减小,色谱流出峰形的不对称偏差度明显增大;吸附剂吸附容量的减小也将引起色谱流出峰形的不对称偏差度的增加;色谱流出峰形的不对称偏差度与进科体积、浓度和流体线速,以及轴向扩散系数的增大成正比。 相似文献
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Qingli Qian Shouyan Shao Fang Yan Chen Ling Fengwen Yan Hongbing Cao Cun-Yue Guo Guoqing Yuan 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(9):1453-1457
Ag nanoparticles (AgNPs) were used as adsorbent to remove trace iodide from acetic acid. Under identical conditions, AgNPs adsorbent with 0.5 wt % Ag has the same performance as commercial adsorbent with 10 wt % Ag+. In addition, Ag loss of AgNPs adsorbent is remarkably lower than that of commercial adsorbent. The Ag content in AgNPs adsorbent affects its adsorption performance, and the optimal content is 1.0 wt %. Saturated AgNPs adsorbent can be regenerated by hydrogen reduction and reused with satisfying performance. The properties of AgNPs adsorbent are based on surface effect of nanoparticles, differing from commercial Ag+ type adsorbents. In a word, AgNPs adsorbent is of high efficiency, low Ag loss and easy recycling, thus making it ??green adsorbent?? for removing iodide from acetic acid. 相似文献
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R. Leboda 《Chromatographia》1981,14(9):524-528
Summary The surface properties of complex adsorbents prepared through the pyrolysis of dichloromethane on the surface of silica gel were investigated. The reaction was carried out in a specially constructed reactor at 400–500°C. The construction and performance of the reactor are described. The modification of the silica gel surface by pyrogenic carbon results in its chemical but not energetical homogeneity. Such adsorbents usually show strong adsorptive properties which limits their use in chromatography. A simple method of homogenizing the porous structure and energetic properties of the adsorptive centers of such adsorbents is presented. The method consists of an additional pyrolysis of an alcohol or other substances on the surface of the carbon-silica adsorbent. Such reactions were carried out under both static and dynamic conditions. The properties of the modified adsorbent depend on the reaction conditions and on the type of the additionally pyrolysed substance. 相似文献
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<正> 顺丁橡胶与丁苯橡胶在性能上的差别,在于其分子主链上缺少象苯基那样的侧基。而中乙烯基聚丁二烯的分子主链上有相当数量的乙烯基侧基,它弥补丁顺丁胶的不足之处。故日益受到人们的注意。目前,已工业化的中乙烯基聚丁二烯所用的催化剂为烷基锂体系,其聚合物除了1,2-结构外,其余部分反-1,4结构占多数。我们在前文曾经报 相似文献