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221.
固定n(Ce)/n(Zr)比为0.67/0.33,用共沉淀法制得一系列CeO2-ZrO2-Al2O3固溶体.采用这些固溶体作载体,以Fe2O3为活性组分,用浸渍法制备了一系列催化剂.BET结果显示,将适量Ce0.67Zr0.33O2引入到Al2O3载体中有助于催化剂保持较高的比表面积.TPR结果显示,载体中引入适量的Ce0.67Zr0.33O2可以改善催化剂的氧化还原性能.XRD结果表明,Fe2O3在CeO2-ZrO2-Al2O3载体上呈现出良好的分散状况,老化前后催化剂的晶相结构基本无明显变化.特别是当载体中m(Ce0.67Zr0.33O2)∶m(Al2O3)的值为1∶2时,Fe2O3/CeO2-ZrO2-Al2O3催化剂在甲烷催化燃烧中显示出最佳的催化性能和抗高温老化性能. 相似文献
222.
Feng Zhang Ya Zhuo Li Da Wei Gao Ji Kui Sun Yu Min Zhang 《中国化学快报》2007,18(7):791-794
A series of new diethers were obtained by alkylation of furoin under microwave irradiation (MWI) in phase transfer catalysis (PTC) conditions. The products of alkyl halides were synthesized in good yields (>75%) within a few minutes, and the products of dihalides were synthesized in fair yields (about 45%). The yields are dramatically improved compared to conventional heating under the same conditions, in spite of similar profiles of rising in temperature. 相似文献
223.
利用N,N-二(2-氯乙基)氨基磷酰二异氰酸酯和胺的加成反应,合成了2,4,6三氧-1,3,5,2三氮磷杂环己烷衍生物,它们的结构经^1HNMR,IR和元素分析所证实。初步生物活性测试结果表明,部分化合物具有一定的抗肿瘤活性。 相似文献
224.
The efficient utilization of carbon dioxide (CO2) as a C1 feedstock is of great significance for green and sustainable development. Therefore, the efficient chemical conversion of CO2 into value-added products has recently attracted a lot of research attention in recent years. The transformation of CO2 generally requires high-energy substrates, specific catalysts, and harsh reaction conditions due to its high thermodynamic stability and kinetic inertness. Consequently, several efforts have been dedicated toward the development of high-performance catalysts and new reaction routes for CO2 conversion over the last few decades. To date, many routes of convert CO2 into value-added chemicals have been proposed, together with the development of heterogeneous and homogeneous catalysts. Among the advanced catalysts reported to date, ionic liquids (ILs) have been widely investigated and show great potential for the efficient, selective, and economical conversion of CO2 into highly valuable products under mild conditions, even under ambient conditions. Some task-specific ILs have been designed with unique functional groups (e.g., —OH, —SO3H, —NH2, —COOH, and —C≡N), which can act as the solvent, absorbent, activating agent, catalyst, or cocatalyst to realize the transformation of CO2 under metal-free and mild conditions. In addition, a variety of catalytic systems composed of ILs and metal catalysts have also been reported for the transformation of CO2, in which the combination of the IL and metal catalyst is responsible for CO2 conversion with high efficiency. In this review article, we summarize the recent advances in IL-mediated CO2 transformation into chemicals prepared via C—O, C—N, C—S, C—H, and C—C bond forming processes. ILs that can chemically capture CO2 with high capacity are first introduced, which can activate CO2 via the formation of IL-based carbonates or carbamates, thus realizing the transformation of CO2 under metal-free and mild conditions. Recent progress in IL-mediated CO2 transformations to form carbonates and various kinds of N- and S-containing compounds (e.g., oxazolidinones, ureas, benzimidazolones, formamides, methylamines, benzothiazoles, and other chemicals) as well as CO2 hydrogenation to give formic acid, methane, acetic acid, low-carbon alcohols, and hydrocarbons has been summarized in this review with a focus on the reaction routes, catalytic systems, and reaction mechanism. In these reactions, ILs can simultaneously activate the substrate via strong H-bonding in addition to activating CO2, and the cooperative effects among the ionic and molecular species and metal catalysts accomplish the reactions of CO2 with various kinds of substrates to afford a wide range of value-added chemicals. Finally, the shortcomings and perspectives of ILs are discussed. In short, IL-mediated CO2 transformations provide green and effective routes for the synthesis of high-value chemicals, which may have great potential for a wide range of applications. 相似文献
225.
226.
相转移催化法合成N—2—苯基—1,2,3—三唑—4—甲酰基—N′—芳基硫脲 总被引:4,自引:0,他引:4
报道了2-苯基-1,2,3-三唑-4-甲酰氯和硫氰酸铵在PEG-400固液相转移催化下与芳胺反应,制得一系列新的含2-苯基-1,2,3-三唑环的硫脲衍生物,并经IR,^1HNMR和元素进行了结构确证。 相似文献
227.
过渡金属复合氧化物电子组态与表面光伏响应的关系(Ⅰ):M… 总被引:3,自引:0,他引:3
利用表面光电压谱及场诱导表面光电压谱研究了部分过渡金属复合氧化物的电子组态与其光伏响应的关系,结果表明,在过渡金属M(M=Cu,Co,Ni)铁酸盐系列样品中,开壳层的Cu和Co的电荷转移跃迁具有双激发态的成分,其中含有较强的低能电子跃迁;与它们相比,闭壳层的Ni和铁酸盐的CT跃迁则需要较大的能量。 相似文献
228.
纳米级金膜微电极的制作,表征及异相催化反应 总被引:1,自引:0,他引:1
报道了纳米级金膜微电极的制作方法,用XPS及SEM对电极表面进行了表征,考察了该电极的循环伏安及计时电流特性,在聚吡咯修饰微带金电极上成功地实现了葡萄糖氧化酶和电子传递媒体Fe(CN)6^3-的同时固定,并研究了GOD/Fe(CN)6^3-/PPy微酶电极对葡萄糖的响应,稳态响应电流与葡萄糖浓度之间存在Michealis-Menten动力学特征。 相似文献
229.
230.