共查询到19条相似文献,搜索用时 45 毫秒
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在Cu/ZnO固体催化剂存在的条件下, 某些醇特别是2-醇对CO加氢合成甲醇的反应具有显著的催化促进作用. 在固体催化和溶剂催化的协同作用下, 由CO/CO2/H2合成甲醇反应可以在443 K的低温和5 MPa的压力条件下高效进行. 初步研究表明, 在443 K以2-butanol为溶剂时, 连续反应40 h的甲醇平均单程产率和选择性分别达到46.51%和98.94%, 并且催化活性稳定. 该反应温度比当今一般工业合成的反应温度降低80℃左右. 因此, 这种新过程的最终开发成功必将对甲醇合成工业产生重要影响. 相似文献
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以甲醇与巯基乙酸为起始原料合成了3-氧代-4-甲酸甲酯四氢噻吩(Ⅲ),产物通过1H NMR,13C NMR,HRMS等表征。研究了无机碱(NaHCO3、Na2CO3、K2CO3、NaOH、KOH)与有机碱(乙胺、三乙胺、吡啶、甲醇钾),不同溶剂,以及温度对合成3-氧代-4-甲酸甲酯四氢噻吩收率的影响,结果表明:有机碱效果优于无机碱;甲苯为较优溶剂;温高反应有利于Ⅲ的合成。用甲苯作溶剂,吡啶为碱催化剂,在80℃下反应2小时,3-氧代-4-甲酸甲酯四氢噻吩收率达78%。 相似文献
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流动CO2-H2O系统中白云岩的溶解研究使用了旋转盘和催化剂技术.实验在与CO2分压分别为30~105Pa达到平衡的H2O-CO2溶液中进行,结果表明远离平衡时的白云岩溶解速率R与旋速w有关.实验结果可用经过改进的扩散边界层(DBL)理论模型获得解释.此外,在溶液中加入能加速CO2转换反应的碳酸酐酶催化剂,促进了白云岩的溶解.发现不同CO2分压条件下存在着较大的差异.从这些实验观测可以得出结论:改进的DBL理论模型能以满意的精度预测远离平衡时不同CO2分压条件下的白云岩溶解速率及其变化机理. 相似文献
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随着全球能源消耗的不断增长和环境污染问题的日益严重,寻找清洁、高效的CO2利用路径成为研究热点。甲醇由于用途广泛,既是重要的化工原料,也是一种新型清洁能源。CO2催化加氢制甲醇过程不仅实现CO2减排,还是碳资源循环利用的有效途径之一,对解决能源紧缺和环境问题具有重要意义。高活性、高选择性和高稳定性的CO2加氢制甲醇催化剂的开发一直是该过程的核心技术。本文综述了二氧化碳加氢制甲醇的研究进展,主要介绍了反应机理和催化剂,并以Cu基催化剂重点总结了活性位、载体和助剂对催化性能的影响,最后对二氧化碳加氢制甲醇的应用前景进行了展望。 相似文献
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采用浸渍法制备了CuO/TiO2负载型催化剂,并将其用于CO2加氢制甲醇反应。重点考察了铜的负载量对催化剂性能的影响,并对其物化性能和催化性能之间的关系进行了讨论。结果发现,随着铜负载量的增加,催化剂中金属铜的比表面先增加后减小,当铜的负载量为10%(质量百分数)时达到最大值。催化剂的表面碱性位数量随铜含量的增加持续减小,中等碱位和强碱位的强度下降。当铜的负载量不高于10%时,CO2的转化率与铜的比表面积呈线性关系。甲醇选择性与催化剂的表面碱位性质有关,过强的碱性位会降低甲醇选择性。 相似文献
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A fast synthesis for Zintl phase compounds of Na3SbTe3, NaSbTe2 and K3SbTe3 by microwave irradiation
Gen-Tao Zhou V.G. Pol Riki Kerner Yuri Koltypin 《Journal of solid state chemistry》2004,177(1):361-365
The microwave irradiation technique was used to prepare three Zintl phase compounds Na3SbTe3, NaSbTe2 and K3SbTe3. The as-prepared products were analyzed and characterized by XRD, EDX and SEM techniques. Higher microwave oven power and shorter irradiation time are required for the synthesis of Na3SbTe3, whereas lower oven power and longer irradiation time are needed for NaSbTe2. Moderate microwave irradiation conditions facilitate the formation of pure K3SbTe3. Pure phase of Na3SbTe3 are directly obtained by this technique for the first time. Compared with the traditional high-temperature solid-state synthesis, the microwave reaction required a considerable shortened reaction time for the preparation of the three Zintl compounds. The initial driving force for these reactions originates from the interaction of microwave electric field with alkali metals (Na and K) and Sb powders. 相似文献
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Recyclable Palladium Catalysts for the Heck/Sonogashira Reaction under Microwave‐assisted Thermomorphic Conditions
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Norman Lu Kwan‐Yu Lin Chieh‐Keng Li Chih‐Chieh Kung Yun‐Peng Yeh Yao‐Yi Cheng Ling‐Kang Liu 《中国化学会会志》2015,62(1):64-72
The reaction of allyl palladium(II) chloride dimer and 4,4′‐bis(RfCH2OCH2)‐2,2′‐bpy, 1a–b , in the presence of AgOTf resulted in the synthesis of cationic palladium complex, [Pd(η3‐allyl)(4,4′‐bis‐(RfCH2OCH2)‐2,2′‐bpy)](OTf), 2a–b where Rf = C9F19 ( a ), C10F21 ( b ), respectively. The reaction of [PdCl2(CH3CN)] or K2PdCl4 with 1b , gave rise to the synthesis of [PdCl2(4,4′‐bis‐(C10F21CH2OCH2)‐2,2′‐bpy)], 3b . The quantitatively determined solubility curves of 2a–b and 3b in DMF indicated dramatic increase of solubility for 2a – b and 3b from ?40 to 90 °C. The catalyst‐recoverable Pd‐catalyzed Heck/Sonogashira reactions were successfully achieved in DMF with microwave‐assistance. The cationic Pd‐catalyzed Heck arylation of methyl acrylate was selected to demonstrate the feasibility of recycling 2a–b using DMF as a solvent under microwave‐assisted thermomorphic conditions. At the end of each cycle, the product mixtures were cooled, and then the catalysts were recovered by decantation. The Heck arylation catalyzed by 2b under microwave‐assisted mode exhibited good recycling results favoring the trans product. To our knowledge, this is the first example of cationic Pd‐catalyzed Heck arylation under microwave‐assisted thermomorphic conditions. Additionally, recoverable 3b ‐catalyzed Sonogashira reactions were also achieved successfully in DMF. The reactions under microwave‐assistance gave much better results in yield and in efficiency than that under conventional thermal heating. 相似文献
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Cu/NiO-V2O5/SiO2催化剂光催化CO2和甲醇合成碳酸二甲酯的研究 总被引:5,自引:0,他引:5
采用表面改性法和等体积浸渍法制备了NiO-V2O5/SiO2和Cu/NiO-V2O5/SiO2光催化剂. 用TPR, XRD, UV-Vis DRS, IR和TPD-MS技术对催化剂的结构、吸光性能和化学吸附性能进行了表征, 研究了催化剂上CO2和甲醇光促表面催化反应的反应性能. 结果表明, 半导体NiO和V2O5复合后部分形成了Ni2+—O—V5+键联, 而且NiO和V2O5在催化剂表面有相互修饰作用, NiO的加入有助于提高V2O5在载体SiO2表面的分散程度, 抑制V2O5的聚集, 而且金属Cu和NiO的引入扩展了催化剂的光响应范围. 在催化剂表面存在多种活性吸附位, 催化剂对CO2和甲醇的有效吸附使得其在较低温度下就能促进碳酸二甲酯的紫外光化学合成. 用Cu/NiO-V2O5/SiO2催化剂, 在常压、空速300 h-1、140 ℃和125 W紫外灯辐照的情况下, CH3OH的转化率为14.2%, 碳酸二甲酯的选择性可达89.9 %. 相似文献
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Germatranes bearing a ferrocenylalkoxyl moiety have been obtained by the reaction of HOGe(OCH2CH2)3N with various ferrocenyl alcohols. A convenient new synthesis method of FcCH2OGe(OCH2CH2)3N was reported. FcCH2OGe(OCH2CH2)3N was prepared in 93% yield when FcCH2OH reacted with HOGe(OCH2CH2)3N in chloroform at room temperature in the presence of molecular sieves (3 Å) as a dehydrating agent. All compounds were characterized by elemental analysis, 1H NMR and IR spectroscopy. The molecular structures of FcCH2OGe(OCH2CH2)3N and FcCH(CH3)OGe(OCH2CH2)3N have been determined by X‐ray diffraction. The antitumor activities of FcCH2OGe(OCH2CH2)3N and p‐FcC6H4CH2OGe(OCH2CH2)3N were determined. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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Guoqiang Hou Qi Wang Dr. Di Xu Haifeng Fan Kaidi Liu Yangyang Li Prof. Xiang-Kui Gu Prof. Mingyue Ding 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(19):e202402053
Direct synthesis of dimethyl carbonate (DMC) from CO2 plays an important role in carbon neutrality, but its efficiency is still far from the practical application, due to the limited understanding of the reaction mechanism and rational design of efficient catalyst. Herein, abundant electron-enriched lattice oxygen species were introduced into CeO2 catalyst by constructing the point defects and crystal-terminated phases in the crystal reconstruction process. Benefitting from the acid-base properties modulated by the electron-enriched lattice oxygen, the optimized CeO2 catalyst exhibited a much higher DMC yield of 22.2 mmol g-1 than the reported metal-oxide-based catalysts at the similar conditions. Mechanistic investigations illustrated that the electron-enriched lattice oxygen can provide abundant sites for CO2 adsorption and activation, and was advantageous of the formation of the weakly adsorbed active methoxy species. These were facilitating to the coupling of methoxy and CO2 for the key *CH3OCOO intermediate formation. More importantly, the weakened adsorption of *CH3OCOO on the electron-enriched lattice oxygen can switch the rate-determining-step (RDS) of DMC synthesis from *CH3OCOO formation to *CH3OCOO dissociation, and lower the corresponding activation barriers, thus giving rise to a high performance. This work provides insights into the underlying reaction mechanism for DMC synthesis from CO2 and methanol and the design of highly efficient catalysts. 相似文献
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《天然气化学杂志》2012,(4):476-479
Promoted catalytic reaction between methanol and CO2 for dimethyl carbonate(DMC) synthesis is conducted over K2CO3/CH3 I catalyst in the presence of ionic liquid under microwave irradiation.The effect of ionic liquids incorporated with microwave irradiation on the yield of DMC is investigated.DMC was found to form at lower temperature in a relative short time,which indicated an enhanced catalytic process by ionic liquid.Among the ionic liquids used,1-butyl-3-methylimidazolium chloride is the most effective promoter.Density functional theory calculations indicate that CO2 bond lengths and angles changed due to the molecular interaction of ionic liquid and CO2,resulting in the activation of CO2 molecules and consequently the acceleration of reaction rate. 相似文献
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J. R. Wells Floyd L. Wiseman Dale C. Williams J. Steven Baxley D. F. Smith 《国际化学动力学杂志》1996,28(7):475-480
The gas-phase reaction products of the OH radical with 2-ethoxyethyl acetate (EEA, CH3C(O)OCH2CH2OCH2CH3) have been investigated. 1,2-Ethanediol acetate formate (EAF, CH3C(O)OCH2CH2OC(O)H) and ethyl formate (EF, HC(O)OCH2CH3) were identified as the two main products. A third product, ethylene glycol diacetate (EGD, CH3C(O)OCH2CH2OC(O)CH3), was also observed. EAF, EF, and EGD formation yields were determined to be 0.37 ± 0.03 and 0.328 ± 0.018 and 0.040 ± 0.005, respectively. Proposed reaction mechanisms are discussed and compared with these data. © 1996 John Wiley & Sons, Inc. 相似文献
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A direct method of synthesis of 1-organylsilatranes by the reaction of organyltrichlorosilanes with tris(2-hydroxyethyl)amine was developed. 1-Organylsilatranes RSi(OCH2CH2)3N with R = Me, Et, Ph, ClCH2, ICH2, Cl(CH2)3 were prepared by this method in up to 72% yield. 相似文献