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环氧环己烷作为一种重要的中间体在有机合成中具有很高的应用价值。由环己烯环氧化制备环氧环己烷极易发生烯丙基氧化、环氧环己烷开环水解、深度氧化等副反应,因此利用价廉易得的氧化剂高选择性地生产环氧环己烷仍然是一个挑战。从氧化剂类型入手,对近期环己烯环氧化反应体系中催化剂种类进行总结,提出各种催化体系面临的主要问题。分析表明催化剂上自由基激发位点、酸性位点是造成环己烯烯丙基氧化、环氧环己烷开环水解副反应产生的主要原因,为催化剂的设计开发提供研究方向。 相似文献
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钯配合物催化环己烯氧化合成环己酮的研究进展 总被引:4,自引:1,他引:3
综述了钯配合物催化环己烯氧化合成环己酮的研究进展。总结了环己烯氧化合成环己酮的催化体系及其催化活性。着重介绍了PdSO4 /HPA (杂多酸 ) ,Pd (OAc) 2 /BQ (苯醌 ) ,Pd (OAc) 2 /FePc (酞菁铁 ) ,Pd(OAc) 2 /HQ (氢醌 ) /FePc ,Pd (OAc) 2 /HQ /HPA ,Pd (NO3 ) 2 /CuSO4 /HPA等催化体系催化环己烯氧化的活性及其作用机理。讨论了影响环己烯氧化活性的因素 相似文献
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研究了三辛基甲基氯化铵(MTAC)、三十二烷基三甲基氯化铵(TMAC)、十六烷基三甲基溴化铵(HTAB)、十八烷基三甲基溴化铵(OTAB)以及聚乙二醇(PEG-400)等5种相转移催化剂对苯乙烯-丁二烯-苯乙烯嵌段共聚物环氧化反应的影响.结果表明,MTAC的环氧化效果最好,当其质量分数为1.0%时,可使环氧化苯乙烯-丁二烯-苯乙烯嵌段共聚物(ESBS)的环氧基质量分数从18.1%提高到20.1%;HTAB和PEG-400有利于ESBS的环氧基质量分数的提高;而OTAB和TMAC由于自身较大的分子体积反而使ESBS的环氧基质量分数下降.傅里叶变换红外光谱分析表明,MTAC可以有效抑制环氧基开环副反应的发生. 相似文献
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利用2,2-二乙基丙二酰氯、2,2-二甲基丙二酰氯或2,2-二氟丙二酰氯与α-氨基异丁酸、双(三氯甲基)碳酸酯、4,5-二氯邻苯二胺以及铁离子制得大环多胺Fe(Ⅲ)配合物,考察了反应温度、H2O2用量、大环多胺配体的结构和大环多胺Fe(Ⅲ)配合物的用量对环已烯环氧化反应的影响.结果表明,该催化剂在CH2Cl2中,以H2... 相似文献
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介绍苯乙烯环氧化制取环氧苯乙烷的几种催化体系,重点叙述了Mn、Ag、Ti、Co、Fe等负载型催化剂,同时介绍了具有巨大潜力的席夫碱金属配合物催化剂的前景。 相似文献
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介绍了烯烃聚合催化剂的发展历程,分别讨论了Ziegler-Natta催化剂、茂金属催化剂和后过渡金属催化剂的研究情况,最后,提出了烯烃聚合催化剂的发展趋势。 相似文献
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Jing‐min Gao Li Wang Hao‐jie Yu An‐guo Xiao Wen‐bing Ding 《Propellants, Explosives, Pyrotechnics》2011,36(5):404-409
Burning rate catalysts are one of the most important components of rocket propellants and are able to enhance solid propellant burning rates. There are several kinds of burning rate catalysts such as nanometal burning rate catalysts, nanometal oxide burning rate catalysts, compound burning rate catalysts, ferrocene and its derivatives burning rate catalysts, and so on. This article reviews the recent research processes in burning rate catalysts. 相似文献
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Two series of LaMnO3 supported noble metal (Pt, Pd, Rh) catalysts prepared by the citrate method and calcined in air at 600 and 800 °C, respectively, were investigated. The catalysts resulting from method A were prepared by simultaneous incorporation of the noble metals during perovskite preparation and those following method B were generated by impregnation of the calcined perovskites with the noble metal compounds. The noble metals form solid solutions with the perovskite lattice. Reduction of the catalysts with hydrogen prior to the catalytic reaction led to a significant enhancement of the catalytic activity. During the catalytic reaction, the noble metal clusters are partially transformed to highly dispersed noble metal oxides or nonstoichiometric noble metal oxide phases, which are the catalytically active phases for the total oxidation of methane. The best results were obtained with the Pd containing catalysts prepared by method B. 相似文献
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Nano-gold particles supported on different alkaline earth oxides (viz. MgO, CaO, BaO and SrO), Gr. IIIa metal oxides (viz.
Al2O3, Ga2O3, In2O3 and Tl2O3), transition metal oxides (viz. TiO2, Cr2O3, MnO2, Fe2O3, CoOx, NiO, CuO, ZnO, Y2O3 and ZrO2), rare earth metal oxides (viz. La2O3, Ce2O3, Nd2O3, Sm2O3, Eu2O3, Tb2O3, Er2O3 and Yb2O3) and U3O8 [all prepared by depositing gold on corresponding metal oxide support by deposition precipitation (DP) and/or homogeneous
deposition precipitation (HDP) method] were evaluated for their catalytic performance in the liquid phase epoxidation of styrene
by tert-butyl hydroperoxide (TBHP) to styrene oxide and also in the solvent-free benzyl alcohol-to-benzaldehyde oxidation (by molecular
oxygen or TBHP) reactions. For the epoxidation, the catalytic performance (styrene oxide yield) of the most promising nano-gold
catalysts prepared by the HDP method was in the following order: Au/MgO > Au/Tl2O3 > Au/Yb2O3 > Au/Tb2O3 > Au/CaO (or TiO2). However, for the oxidation of benzyl alcohol to benzaldehyde by molecular oxygen, the order of choice for the most promising
catalysts (based on benzaldehyde yield) was Au/U3O8 > Au/Al2O3 > Au/ZrO2 > Au/MgO. Whereas, when TBHP was used as an oxidizing agent for the benzyl alcohol oxidation, the order of choice for the
most promising catalysts was Au/U3O8 > Au/MgO > Au/TiO2 > Au/ZrO2 > Au/Al2O3. The catalytic performance of a particular supported nano-gold catalyst was thus found to depend on the reaction catalysed
by them. Moreover, it is strongly influenced by a number of catalyst parameters, such as the metal oxide support, the method
of gold depositon on the support, the gold loading and also on the catalyst calcination temperature. Nano-gold particles-support
interactions seem to play an important role in controlling the deposition of gold (amount of gold deposited and size and morphology
of gold particles), formation of different surface gold species (Au0, Au1+ and Au3+) and electronic properties of gold particles and, consequently, control the catalytic performance (both the activity and
selectivity) of the supported nano-gold catalysts in the reactions. The nano-gold catalysts prepared by the HDP method showed
much better catalytic performance than those prepared by the DP, coprecipitation or impregnation method; in general, the HDP
method provided supported gold catalysts with much higher gold loading and/or smaller size gold particles than that achieved
by the DP and other methods. 相似文献
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介绍了目前加氢脱硫催化剂载体的种类和研究现状,包括氧化物载体、介孔分子筛载体、活性炭载体、酸碱载体等。分析了不同载体所具有的的优缺点,并展望了未来载体的研究方向。 相似文献
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苯乙烯是重要的有机化工原料。随着需求量的逐渐增加,苯乙烯的生产规模在逐渐的增大,生产方法也在不断的改进。乙苯脱氢法仍是其中的主要生产方法。在实验室的条件下,采用等温式乙苯催化脱氢小型装置,考察反应温度以及水和乙苯的进料比对实验结果的影响,并根据实验结果找出实验室条件下最佳的反应温度范围以及合适的进料比范围。 相似文献
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简要介绍了瓜环化学的概念、定义、结构特征及应用新进展。重点综述了:①新型瓜环超分子聚合物的自组装合成;②新型瓜环化合物在轻重稀土分离中的应用研究;③新型瓜环化合物与碱土金属管状配位聚合物的合成研究。并对瓜环化学的发展进行了展望。 相似文献