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高附加值的苯乙酮是一种非常重要的有机合成中间体。近年来以氧气为氧化剂催化乙苯制苯乙酮是催化有机合成领域的热门课题之一,但此方法尚未解决与氧气匹配的催化体系。较为系统地总结该反应的催化体系,包括金属纳米材料与金属氧化物催化、分子筛催化、碳材料催化、水滑石催化、金属有机框架材料催化、N-羟基邻苯二甲酰亚胺催化等。 相似文献
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以乙苯为起始物料,以空气为氧化剂,采用Co(acac)2为催化剂催化氧化合成苯乙酮,研究了反应过程中的反应时间、反应温度、空气流速和催化剂用量等工艺参数对催化氧化合成苯乙酮的影响并确定最优的合成方案。实验结果表明:乙苯催化氧化合成苯乙酮的最优的合成方案:28 h为最佳反应时间,100℃为最佳反应温度,空气作为气源,100 mL/min为最佳流速,Co(acac)2最佳用量为乙苯质量分数1‰,在此合成方案下,乙苯转化率最优,为60.43%,苯乙酮收率最高,为92.55%。Co(acac)2在催化乙苯氧化合成苯乙酮的反应中具有显著优势,它的用量较小、对设备腐蚀较小、成本低廉,能够有效提升氧化效率,降低生产成本,因此具有广阔的工业应用前景。 相似文献
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为了制备负载型介孔分子筛V/SBA-15并研究其在乙苯制苯乙酮反应中的催化性能,以P123(三嵌段共聚物)为模板剂,正硅酸乙酯为硅源,柠檬酸氧钒配合物为前驱体,在酸性条件下采用水热法一步合成了V/SBA-15有序介孔材料,利用XRD,BET,FT-IR等手段对所合成的V/SBA-15材料进行了结构表征,并在乙苯制苯乙酮反应中以苯乙酮选择性和收率来验证催化剂的催化性能。实验结果表明:此合成材料具有类似于SBA-15的高度有序的六方介孔结构,活性组分钒均匀分散在介孔氧化硅基体中;在催化氧化乙苯制苯乙酮反应的优化条件下,苯乙酮选择性和收率分别为80.87%,35.26%。 相似文献
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以硝酸铜为铜源,硝酸钴为钴源,对超稳分子筛(USY)进行单金属和双金属的改性,采用浸渍法制备一系列金属改性的USY分子筛催化剂,并对其进行X射线衍射(XRD)、N2吸附脱附、傅里叶红外光谱分析(FTIR)、扫描电子显微镜(SEM)的表征分析。以乙苯氧化制苯乙酮为探针反应,在间歇式反应釜中催化氧化乙苯,考察金属负载量以及双金属改性对USY分子筛催化剂催化氧化性能的影响。结果表明,钴对于铜在USY分子筛上的均匀分布以及活性中心铜对乙苯氧化的催化作用具有协同促进作用,当Co和Cu的负载量分别为5%和20%时,5% Co/20% Cu-USY(质量分数)催化剂对乙苯催化氧化反应的性能最优,其乙苯的转化率和苯乙酮的选择性分别达到29.8%和87.2%。催化剂重复使用4次后其活性和选择性无显著降低,具有良好的结构稳定性。 相似文献
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Ru(III), Cu(II) and Zn(II) complexes of imidazole (ImzlH) have been synthesized in the supercages of zeolite-Y by flexible ligand method and characterized by spectroscopic (IR and UV?CVis) studies, XRD and thermogravimetric analysis, surface area, and pore volume measurements. These complexes were screened for their catalytic study towards the oxidation of ethylbenzene to a mixture of acetophenone, benzaldehyde and styrene using tert-butylhydroperoxide (TBHP) as an oxidant. A best-suited reaction condition has been optimized for these catalysts by varying the amount of the oxidant and catalyst, reaction time and volume of solvent for maximum transformation of ethylbenzene. Under the optimized reaction conditions, [Cu(ImzlH)]-Y gave 79.3% conversion after 1?h of reaction time. All these catalysts were more selective towards acetophenone formation. Among the prepared catalysts, zeolite encapsulated Cu(II) complex was found to be more active than the corresponding Ru(III) and Zn(II) complexes and all the complexes were stable enough to be reused. The catalytic activities of the neat complexes and metal exchanged zeolites were also compared with the zeolite encapsulated metal complexes. 相似文献
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Iron nanowire filled carbon nanotubes (Fe@CNTs) were synthesized by chemical vapor deposition method and employed as heterogeneous catalysts for selective oxidation of ethylbenzene to acetophenone with molecular oxygen. The results showed that filled iron nanowires efficiently enhanced the catalytic activity of CNTs, arising from improving electron transfer. Moreover, Fe@CNTs could be easily separated from the reaction mixtures by external magnet and displayed excellent stability with no significant loss of catalytic activity after six cycling reactions. The result presented herein paves the way for the development of novel carbon catalysts for the liquid phase oxidation of ethylbenzene. 相似文献
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Xiaomei Yang Ying Wang Lipeng Zhou Chen Chen Wei Zhang Jie Xu 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2010,85(4):564-568
BACKGROUND: Organocatalysis, a promising strategy for the oxidation of organic compounds, does not involve the use of a catalytic metal. In this work, an efficient organocatalyst system consisting of 2,3‐dichloro‐5,6‐dicyano‐benzoquinone (DDQ) and N‐hydroxyphthalimide (NHPI) was studied. RESULTS: 72.2% conversion with 92.3% selectivity for acetophenone was obtained in ethylbenzene oxygenation catalyzed by DDQ/NHPI under 0.3 MPa of molecular oxygen at 80 °C for 10 h. In addition, other hydrocarbons were also oxidized with high efficiency using this catalyst system. UV/Vis spectroscopy of the catalytic system indicated that DDQ accelerated the generation of free radical phthalimido‐N‐oxyl (PINO) by abstracting a hydrogen atom from NHPI. CONCLUSION: An efficient organocatalyst system consisting of DDQ and NHPI for selective oxidation of hydrocarbons to corresponding ketones with molecular oxygen as oxidant is reported. DDQ promoted the generation of PINO from NHPI, and the oxidation reaction was accelerated via PINO. This organocatalyst system should be useful for the design of highly selective catalysts for hydrocarbon oxidation. Copyright © 2010 Society of Chemical Industry 相似文献
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酰胺键的合成是有机化学中非常重要和有意义的反应之一。国内外学者已对酰胺键的形成进行了长期研究,目前合成酰胺的底物和方法多种多样,然而,这些合成方法存在各种各样的资源浪费和环境污染问题。羧酸和胺之间的催化脱水缩合反应是合成相应酰胺的最理想方法,利用羧酸和胺在催化剂作用下直接缩合形成酰胺,避免了使用活化试剂带来的诸多问题。近年来以硼类和过渡金属为主体的催化剂得到广泛研究,并取得了一系列成果。本文主要介绍了以羧酸和胺为底物,同时符合绿色化学理念的催化合成方法,通过对这些催化剂催化性能的总结与分析,阐述了各种催化剂的优缺点。其中硼化合物催化的直接酰胺化反应是研究较多、前景最为诱人的方法,因此基于硼类化合物的特殊结构,设计更具活性的此类催化剂将是今后研究发展的方向。 相似文献
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金属有机骨架材料(MOFs)作为典型的自模板材料已被广泛应用于催化、电化学和吸附等领域。采用水热法合成两种含氮的Co-Ni-MOF和Co-Cu-MOF材料,并以两种材料为模板剂,在不同温度热解制备Co-Ni@NC和Co-Cu@NC纳米催化剂。将两种纳米催化剂用于乙基苯选择性氧化制备苯乙酮反应, 研究热解温度对催化剂催化活性的影响。结果表明,随着热解温度升高,催化活性逐渐增强,当热解温度达到900 ℃时,催化活性最高,苯乙酮收率为98%~99%,催化剂还表现出较好的重复使用性能。 相似文献
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合成系列新型杂多酸盐Co(8-n)/2(Cpyr)nP2Mo16V2O62(n=1~8),用原子吸收光谱、傅里叶变换红外光谱、X射线衍射、热分析方法表征杂多化合物的结构,将其应用到乙苯氧化合成苯乙酮的反应中,并探讨其反应机理。结果表明,新型杂多酸盐Co(8-n)/2(Cpyr)nP2Mo16V2O62具有Dawson结构,过渡金属钴与活性中心钒之间存在协同作用,提高了催化剂的催化活性,其中Co2(Cpyr)4P2Mo16V2O62催化活性最高,乙苯的转化率达到83.7%,苯乙酮的收率达到74.8%。 相似文献