共查询到19条相似文献,搜索用时 593 毫秒
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本文分析了乙二胺和正丁胺为模板剂,在水热体系Na2O-SiO2-Al2O3-H2O中合成了ZSM-35沸石,并利用XRD,SEM,IR及CO加氢反应手段考察了其物理化学特性。结果表明,模板剂对ZSM-35沸石的合成,结构,形貌,红外振动,稳定性及催化性能有显著的影响作用。 相似文献
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考察了Na2O-SiO2-Al2O3-EDA干粉体系中是否加入NaF以及加入量对产品物相及结晶度的影响。结果表明,当反应体系不加NaF时,产物为结晶度高的单一晶相的ZSM-35沸石,而体系中加入NaF时,产品中有ZSM-5沸石物相出现,而且随着NaF加入量的增加,产品物相完全转化为具有很高结晶度的单一相ZSM-5沸石。说明氟离子对干粉体系中ZSM-5沸石的生成具有明显的结构定向作用 相似文献
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杂原子Fe—ZSM—5分子筛的合成及表征 总被引:4,自引:1,他引:4
本文采用水热合成法,在SiO2-FeO3-EDA-H2O体系中成功地合成了Fe-ZSM-5型沸石分子筛。并采用XRD,IR,SEM及MTG反应考察了其物理化学特性,结果表明,分子筛的单位晶胞体积随Fe杂原子含量的增加而膨胀;骨架在1100cm^-1处的反对称伸缩振动峰向低波数移动,说明Fe杂原子进入了分子筛骨架,。 相似文献
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SYNTHESISOF1H,1'HBIS(BENZ-△~4-IMIDAZOLINE)2,2'-SPIRO-TITANIUMDICHLORIDEWeiRongbao;LiangYa;WuJinguo;XueQifeng(Dept.ofChem.Eng.... 相似文献
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STUDYONTHESORPTIONBEHAVIOROFN-METHYL-2-THIO-IMIDAZOLERESINFORRh(Ⅲ)ANDSEPARATIONOFRh(Ⅲ)WITHCOMMONMETALIONSBYUSINGMTIRChenYiyon... 相似文献
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含铜MFI分子筛的H2-TPT和O2-TPD研究 总被引:8,自引:2,他引:6
采用H2-TPR和O2-TPD手段考察了不同金属离子交换的ZSM-5分子筛催化剂上的氢还原性能和氧脱附性能.发现Cu-ZSM-5催化剂的储氧能力及氧脱附性能优于Co-ZSM-5和Fe-ZSM-5催化剂;储氧能力强、低温下氧脱附性能好的催化剂,对NO分解反应的催化活性就高.铜离子是反应的活性中心.添加Ag和Ce可使Cu-ZSM-5催化剂上氧的脱附温度大大降低.Cu-ZSM-5/堇青石整体式催化剂上Cu的存在形式与单纯的Cu-ZSM-5有差异,整体式催化剂上的一价铜数量少,但较稳定. 相似文献
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以金属氧化物及钙钛矿结构化合物为活性组分的ZSM-5催化剂上NOx选择性还原研究 总被引:2,自引:1,他引:1
研究了在水蒸汽存在条件下,以NH3为还原剂,金属/ZSM-5催化剂和负载于ZSM-5上的钙钛矿结构催化剂上的NOx选择性催化还原(SCR)性能。实验结果表明,当反应气中通入水蒸汽时,各样品的催化活性均下降,同时伴随着N2选择性的增加。而Cu-ZSM-5样品却表现出独特的性能,在所有测定样品中具有最高的NOx转化率(在450℃时达到69%),当有水蒸汽存在时,其活性没有下降,反而有所增加,450℃时 相似文献
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《应用有机金属化学》2017,31(6)
The effect of weak base modification on the catalytic performance of ZSM‐5 catalyst for conversion of methanol to aromatics was investigated. The catalysts were characterized using X‐ray diffraction, X‐ray fluorescence, N2 adsorption–desorption, NH3 temperature‐programmed desorption, Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetry. The results showed that catalysts treated with weak base (NaHCO3, Na2CO3 and NH3⋅H2O) exhibited a pore structure with interconnected micropores and mesopores. The existence of mesopores was beneficial for improving the diffusion of reactants and products, and the coke deposition resistance capacity of treated catalysts was enhanced greatly. Meanwhile, compared to traditional ZSM‐5 zeolite, the ratio of Brønsted to Lewis (B/L) acid sites of ZSM‐5/NH3⋅H2O (B/L = 7.35) zeolite slightly increased but the amount of acid sites reduced, while those of ZSM‐5/NaHCO3 (B/L = 0.127) and ZSM‐5/Na2CO3 (B/L = 0.107) significantly reduced. Further, the catalyst treated with NH3⋅H2O solution was evaluated in the methanol to aromatics reaction and led to an enhanced aromatization reaction rate. The liquid hydrocarbons product distribution exhibited higher aromatic hydrocarbons yield (56.12%) and selectivity (40.28%) of benzene, toluene and xylene (BTX) with isoparaffin content reducing to 26.17%, which could be explained by appropriate B/L acid sites ratio, higher pore volumes and higher surface area. 相似文献
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以Na+型和H+型ZSM-5为载体制备了Fe-ZSM-5催化剂并用于氨选择性催化还原(NH3-SCR)氮氧化物. Fe-H-ZSM-5在新鲜时和750 oC含10%水的空气中老化后,其SCR活性均优于Fe-Na-ZSM-5.表征结果显示, Fe-H-ZSM-5和Fe-Na-ZSM-5的Fe物种分布和酸性位有所不同.高温水热老化后Fe-H-ZSM-5分子筛骨架的脱铝较Fe-Na-ZSM-5严重.水和硫的存在对Fe-H-ZSM-5和Fe-Na-ZSM-5的SCR活性的影响相似,即降低了低温活性,略提高了高温活性. Fe-Na-ZSM-5表现出比Fe-H-ZSM-5更好的抗碳氢中毒性能.这两种催化剂的SO2和碳氢中毒是可逆的. 相似文献
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ZSM‐5 coatings, have been synthesized onto a monolithic cordierite substrate by an environmental friendly and high coating selectivity method—Vapor Phase Transport (VPT). With this method, an aluminosilicate gel coated onto the monolithic cordierite substrate has been transformed into a ZSM‐5 layer under vapors of n‐butylamine and water, n‐Butylamine played a key role in the forming of ZSM‐5 layer on the cordierite substrate. The ZSM‐5/cordierite monolith composites prepared by this method were ion‐exchanged with Cu2+ and tested for the selective catalytic reduction of NO by propane. The deNOx activities of Cu/ZSM‐5 monolith catalysts were not only dependent on the ion‐exchange methods, but also on the ZSM‐5 loading of the monolith catalysts. The best result was obtained over the Cu (B3)/ZSM‐5 monolith catalyst, which had a ZSM‐5 loading of about 13% and was prepared by a pressure exchange procedure. At a temperature of 723 K and a space velocity of 10,000 h?1 (based on the monolith volume), 85% of NO conversion and 93% of C3H3 conversion were achieved over the Cu(B3)/ZSM‐5 monolith catalyst. 相似文献
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Bis(trifluoroaceto) disulfide CF(3)C(O)OSSOC(O)CF(3) was prepared and studied by Raman, photoelectron spectroscopy (PES), and theoretical calculations. This molecule exhibits gauche conformation with both C=O groups cis to the S-S bond; the structure of the OSSO moiety is characterized by dihedral angle delta(OSSO) = -95.1 degrees due to the sulfur-sulfur lone pair interactions. The contracted S-S bond (1.979 Angstroms) and relatively high rotational barrier (19.29 kcal mol(-1) at the B3LYP/6-31G level) of the delta(OSSO) indicate the partial resonance-induced double bond character in this molecule. After ionization, the ground cationic-radical form of CF(3)C(O)OSSOC(O)CF(3)(*+) adopts a trans planar main-atom structure (delta(OSSO) = 180 degrees and delta(OCOS) = 0 degrees ) with C(2)(h) symmetry. The S-S bond elongates to 2.054 Angstroms, while the S-O bond shortens from 1.755 Angstroms in neutral form to 1.684 Angstroms in its corresponding cationic-radical form. The adiabatic ionization energy of 9.91 eV was obtained accordingly. The first two HOMOs correspond to the electrons mainly localized on the sulfur 3p lone pair MOs: 3ppi {36a (n(A)(S))](-1) and 3ppi [35b (n(B)(S), n(B)(O(C)(=)(O)))](-1), with an experimental energy separation of 0.16 eV. The first vertical ionization energy is determined to be 10.81 eV. 相似文献
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A New Practical Route to ZSM‐5 Nanoparticles and Optimization of Synthetic Parameters through D‐optimal Design of Experiments 下载免费PDF全文
Saeed Soltanali Rouein Halladj Alimorad Rashidi Mansour Bazmi Saeed Khodabakhshi 《中国化学会会志》2015,62(9):817-825
A D‐optimal experimental design with three levels of SiO2/Al2O3, template/SiO2, H2O/SiO2, Na2O/SiO2 and TPABr/TPAOH ratio parameters has been used to optimize the experimental parameters by an analysis of variances (ANOVA). The effects of these ratios in the initial synthetic mixture on the size of the ZSM‐5 zeolite nanoparticles have been studied. XRD and FE‐SEM analyses were used to characterize synthetic samples. Fischer test results showed that H2O/SiO2 and TPABr/TPAOH ratios are the most and least effective parameters, respectively, in the range studied. The most important two‐way interaction variables were the interaction of template/SiO2 and TPABr/TPAOH molar ratios. The average particle size was in the 34–79 nm range. Furthermore, a mathematical model for the synthesis of ZSM‐5 zeolite nanoparticles was derived using experimental results. The optimized gel composition is as follows: SiO2/Al2O3=91.20, template/SiO2=0.16, H2O/SiO2=40.42, Na2O/SiO2=0.0147 and TPABr/TPAOH=0. 相似文献