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1.
A series of Sn-Zn modified-MCM41 has been synthesized by direct hydrothermal method and characterized using ICP, XRD, TG/DTA, FT-IR, HRTEM and N2-adsorption techniques. Catalytic performances of the obtained materials were evaluated in the hydroxylation of phenol with H2O2. Results indicated that all the samples exhibited typical hexagonal arrangement of mesoporous structure with high surface area and the heteroatoms were probably incorporated into the framework of MCM41. Catalytic tests revealed that the bimetallic incorporated materials were effective catalysts in the hydroxylation of phenol. The conversion of phenol could be reach to 56.8% for the catalysts with Sn: Zn: Si = 2.69: 4.57: 100 (molar ratio) under the optimized reaction conditions. Moreover, the materials containing Sn and Zn exhibited higher catalytic activity than monometallic Sn and Zn modified MCM41.  相似文献   

2.
王宇红  袁联群  俞磊  项婷婷 《化工学报》2010,61(10):2565-2572
采用水热法合成了双金属镧(La)和钒(V)取代MCM-41分子筛催化剂,使用X射线衍射、N2吸附、傅里叶变换红外光谱、紫外-可见漫反射光谱以及热重等表征技术研究了催化剂的结构。结果表明,该材料具有高度有序的二维六方结构,金属La和V以高度分散的四配位状态存在于分子筛的骨架中。在苯酚过氧化氢羟基化反应中La-V-MCM-41分子筛表现出比TS-1催化剂更好的催化活性和选择性,金属La和V协同作用,在提高H2O2有效利用率的同时,增加了目标产物苯二酚中对苯二酚的含量。La-V-MCM-41催化剂可以通过焙烧活化的方法进行再生使用。  相似文献   

3.
A series of Fe3+ containing catalysts were synthesized using ion-exchange technique over hierarchically porous ZSM-5 (M-ZSM-5) and micro-mesoporous composite ZSM-5/MCM-41 (ZSM-5/MCM-41), respectively. The prepared catalysts were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, N2 adsorption–desorption, UV–Vis spectroscopy, temperature programmed reduction and inductively coupled plasma-optical emission spectroscopy. The characterization results exhibit that the hierarchically porous ZSM-5 was synthesized with intracrystalline mesopores, while the micro-mesoporous composite ZSM-5/MCM-41 was prepared with the well-ordered mesopores. Furthermore, the results also prove that the existence of iron in the catalysts was mainly presented in the form of Fe3+ ions. Catalytic performances of the samples for phenol hydroxylation were compared by using H2O2 as oxidant. Under the optimized conditions, Fe3+ ion-exchanged M-ZSM-5 (Fe-M-ZSM-5) shows that a phenol conversion of 42.3% obtained with 92.5% selectivity to dihydroxybenzenes, whereas Fe3+ ion-exchanged ZSM-5/MCM-41 (Fe-ZSM-5/MCM-41) give 46.2% phenol conversion and 90.1% dihydroxybenzenes selectivity, which are all better than most reported results. The recyclability tests show that Fe-ZSM-5/MCM-41 with ordered mesoporous structure and bigger surface area has better anti-deactivation performance than Fe-M-ZSM-5. The excellent catalytic performances were due to the improved diffusion performance with newly created mesopores and the highly active Fe3+ species obtained by ion-exchange technique.  相似文献   

4.
Bulk and MCM41-supported Ni2Mo3N catalysts were prepared using a temperature-programmed reduction (TPR) method and characterized using XRD, TEM, ICP-AES, and N2 adsorption analysis techniques. Their catalytic properties were measured for the simultaneous hydrogenation of p-xylene and naphthalene and compared with Ni/MCM41 and Mo2N/MCM41 catalysts having similar metal loadings. The results indicate that the Ni2Mo3N/MCM41 catalyst exhibits excellent deep hydrogenation activity under mild condition (T = 483 K, P = 3.0 MPa), and that it is more active than either Ni/MCM41 or Mo2N/MCM41 catalyst.  相似文献   

5.
V-HMS catalysts with different vanadium content have been prepared by co-synthesis method using dodecylamine as template. The isolated VO4 species are successfully incorporated into the framework of HMS for the samples with low vanadium content. The effect of various reaction conditions on the hydroxylation of benzene to phenol with H2O2 as oxidant in aqueous acetic acid solvent was investigated where the yield of phenol achieves 11.1% under the optimized condition.  相似文献   

6.
《Catalysis communications》2011,15(1):114-117
Highly active Ru2P/MCM-41 and RuP/MCM-41 catalysts were synthesized by thermal decomposition of ruthenium chloride and hypophosphite precursors. The effect of experimental conditions on the final products is discussed. The results of investigation show that the reaction mechanism of ruthenium phosphide is different from nickel phosphide. Catalytic properties were tested for the hydrodesulfurization of dibenzothiophene and hydrodenitrogenation of quinoline. The results showed that both Ru2P/MCM-41 and RuP/MCM-41 catalysts exhibited higher activities than Ru/MCM-41.  相似文献   

7.
Cobalt(II), Copper(II) and Zinc (II) complexes of 2-methylbenzimidazole (Mebzlh) encapsulated in the super cages of zeolite-Y and ZSM-5 have been synthesized by flexible ligand method and characterized by various physico-chemical measurements. The catalytic activity of encapsulated complexes was investigated for the decomposition of H2O2 and for the hydroxylation of phenol using H2O2 as an oxidant. The hydroxylation of phenol yielded catechol and hydroquinone as the major products. All catalysts show good selectivity for diphenol products. The results showed that conversion of phenol varies in the order [Cu(Mebzlh)]-Y > [Cu(Mebzlh)]-ZSM-5 > [Zn(Mebzlh)]-Y > [Co(Mebzlh)]-Y > [Zn(Mebzlh)]-ZSM-5 > [Co(Mebzlh)]-ZSM-5 after 6 h of reaction time.  相似文献   

8.
Fe loaded Al-MCM-41, (Si/Al = 25, 50, 75 and 100) catalysts were synthesized by hydrothermal method and characterized by the XRD, BET (surface area), FT-IR, and UV- vis and Mössbauer techniques. The liquid phase hydroxylation of phenol with hydrogen peroxide was studied and exclusive formation of dihydroxybenzene was observed. The phenol conversion was found to be almost same at various reaction temperatures viz 40, 60 and 80 °C, but at room temperature only about 30% conversion was recorded. The activity followed the order Fe/Al-MCM-41 (25) > Fe/Al-MCM-41(50) > Fe/Al-MCM-41 (75) > Fe/Al-MCM-41 (100) which was also the order of acidity. Effects of Fe content in Fe/Al-MCM-41 catalysts, solvent, phenol/H2O2 mole ratio on phenol conversion was examined. The reaction was also carried out over 10% iron loaded mordenite and the results are compared.  相似文献   

9.
A study of NiMo catalysts supported on MCM41 modified with alumina prepared by the sol?Cgel method is presented. Ni?CMo phases were impregnated on the supports using the solution method with the purpose to obtain a material whose hexagonal structure of the MCM41 would not be affected with the addition of these active phases. The impregnation of the metals method used in the present work was outstanding, the textural properties of the catalysts decreased from 42 to 67%. There was a diminution in the textural properties of the catalysts with respect to the supports, nevertheless the prepared materials had more significant textural properties that the conventional catalysts of HDS. The adsorption?Cdesorption isotherms of the catalysts did not change considerably with the support source. By DRX was determined the structural properties of the metallic phases present in the material where phases such as NiMoO4, MoO3 and NiO were observed. Support wall thickness was increased with the incorporation of Ni and Mo metals into the materials. By means of Raman spectroscopy, the presence of MoO3 and Mo8O26 4? species was corroborated. Through UV?Cvis where determined NiO of octahedral symmetry as well as Mo of tetrahedral and octahedral symmetry. The main reaction products were biphenyl (BP), cyclohexylbenzene (CHB) and bicyclohexyl (BCH) when the materials were tested in the HDS of DBT.  相似文献   

10.
基于MCM-41的镍基甲烷化催化剂活性与稳定性   总被引:3,自引:2,他引:1  
张加赢  辛忠  孟鑫  陶淼 《化工学报》2014,65(1):160-168
采用浸渍法分别以MCM-41,Al2O3和SiO2 为载体制备了不同镍负载量的甲烷化催化剂,并在连续流动固定床反应装置上对其甲烷化催化活性进行了评价。研究结果表明,与Ni/Al2O3和Ni/SiO2相比,相同镍负载量的Ni/MCM-41催化剂具有更好的催化活性。同时研究了Ni含量对于Ni/MCM-41催化剂催化活性的影响,发现随着Ni含量的增加,CO转化率和CH4收率逐渐升高,并且在Ni含量大于10%(质量分数)以后趋于稳定。在n(H2):n(CO)=3:1、反应压力1.5 MPa、反应温度350℃及质量空速12000 ml·h-1·g-1的反应条件下,10%Ni/MCM-41催化剂CH4选择性达到94.9%,CO转化率接近100%。在100 h催化活性稳定性试验中,10%Ni/MCM-41催化活性无明显下降,表现出良好的催化活性稳定性。采用X射线衍射(XRD)、氮气物理吸附(BET)、热重分析(TG)及氢气程序升温还原(H2-TPR)等技术手段对催化剂进行了表征,结果表明Ni颗粒大小是影响Ni/MCM-41催化剂催化活性的主要因素。  相似文献   

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