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1.
Summary In the present study, twenty four catalysts for low pressure methanol synthesis were prepared according to a pre-designed research program consisting of three stages. In each stage, applying the experimental design techniques, a number of catalysts were synthesized by the co-precipitation method, using different proportions of metal salts solutions. The activities of the catalysts were determined applying a laboratory scale continuous packed bed reactor. It was noted that the calcinations temperature, ageing time and molar ratio of metal nitrates to precipitant, had the highest effects on the activity of the catalysts.  相似文献   

2.
The conversion of ethane into aromatic compounds at 550°C and atmospheric pressure over Zn-ZSM-11 zeolite (Si/Al=17; 2.5 wt.% of Zn as counter ion) has been studied in a flow reactor at different partial pressures of ethane. The observed products at different ethane conversion levels were formed through a variety of processes including ethane dehydrogenation, producing ethylene as the only primary unstable product. Ethylene underwent very rapid reactions through carbenium ion intermediates, producing aromatic hydrocarbons and C1-C4 hydrocarbons as secondary products.  相似文献   

3.
The transformation of n-pentane into aromatic hydrocarbons over Zn-exchanged ZSM-11 zeolite (Zn-ZSM-11) has been studied. The catalyst exhibited a high activity and BTX selectivity for n-C5 conversion at about 538°C, 1 h–1 and 1 atm. Zn-species are effective for the activation of the n-pentane and the transformation of intermediate products into aromatic compounds.
- ZSM-11, (Zn-ZSM-11). - 538°C, 1–1 1 . Zn - .
  相似文献   

4.
Hydrogen production by conversion of methane over Ni-supported zeolite catalysts was investigated, and Ni-supported USY-type zeolite (Si/Al2 = 14.0, 360) was found to have longer catalytic lifetime than Ni-supported silica (Cab-O-Sil) catalyst, which had been reported to have the longest catalytic lifetime for this reaction.  相似文献   

5.
Summary CeO2 nanoparticles were prepared by thermal decomposition of cerous nitrate and then used as supports for CuO/CeO2 catalysts prepared via the impregnation method. The samples were characterized by XRD, HRTEM, H2-TPR and XPS. The catalytic properties of the catalysts for low-temperature CO oxidation were studied by using a microreactor-GC system.  相似文献   

6.
Summary Role of ruthenium in the reduction behavior of Ru-promoted Co/TiO2 catalysts was investigated. Ru could facilitate the reduction but had no effect on water production during reduction.  相似文献   

7.
8.
Summary Hydrotreating (HDT) and hydrodesulfuration (HDS) using an FCC feed were carried out at 673-748 K and 50 MPa total pressure. The effect of vanadium impregnated on a NiMo catalyst supported on sepiolite for HDT and HDS reactions was studied. A commercial NiMo/Al2O3 catalyst was used as reference. The hydrotreating conversions (wt.% HDT) is defined here as the net hydrotreating conversion into products boiling below 653 K. The results were compared with an accelerated ageing test using the catalysts on a FCC feed, with vanadium in the form of naphthenate (2000 ppm of V) added to rapidly deactivate catalysts via metal deposition. The results indicate that vanadium affects more the catalyst supported on sepiolite that the commercial catalyst. Also, at our reaction conditions, the effect of vanadium on sepiolite catalyst is similar, to those used with vanadium impregnated on the catalyst or on the catalyst where the vanadium in naphthenate form was added to FCC feed.  相似文献   

9.
10.
Summary Genesis of an active component in V-Mo-Nb-O catalysts for the oxidation and ammoxidation of ethane was studied. It was shown that the mixing of aqueous solutions of initial reactants leads to the formation of MoV complexes in the solution and to sedimentation of a binary Nb-Mo compound. The latter serves as the basis for the formation of the catalyst active component phase (a triple V-Mo-Nb compound with a variable composition of Mo5O14-like structure) during the subsequent treatment in air at 400°C.  相似文献   

11.
Summary This paper reports the possibility of in situ synthesis of HZSM-5 zeolites films on tubular steel substrate for the improved potential chemical heat sink of fuels, and the performance of prepared membrane catalysts in the endothermic, catalytic cracking of n-decane. Through hydrothermal crystallization, a zeolite / steel composite was obtained which consists of a continuous zeolite film that strongly attaches to the substrate surface. The membrane catalysts are active enough for the n-decane catalytic cracking to provide endothermal ability, and also can suppress the formation of carbon deposits compared with thermal cracking.  相似文献   

12.
Summary The promotion effect of potassium has been studied with the method of Temperature Programmed Surface Carburization (TPSC) technique and H2-TPR. The process of carburization on the catalyst surface was enhanced by addition of potassium was added, so that the probability for the generated alkenes species to be further hydrogenated was increased. As a result, the percentage of the alkenes from C2 to C4 in the products was increased.  相似文献   

13.
The catalytic conversion of ethanol on H3+xPMo12–xVxO40/TiO2 catalysts (x=0,1,2) yielding both the products of alcohol dehydration (ethylene, diethyl ether) and dehydrogenation (acetaldehyde) but also ethane as secondary product is accompanied by the formation of coke. The amount and composition of coke was estimated on the basis of mass balance. The fact that the hydrogen/carbon atom ratio was low (0.6) supports the conclusion that coke is involved in the hydrogenation of primary ethylene.  相似文献   

14.
Summary The catalytic oxidation of phenol over CuZSM-12 (SAR = 200) has been studied using a semi-batch slurry reactor at temperatures of 110; 120 and 130oC, and acidic neutral and basic pH. At 130oC, the phenol undergoes total conversion to carbon dioxide and water in 1.5 h. The kinetic parameters were evaluated using a modified homogeneous-heterogeneous model for the experimental data. Using this modified model, the activation energy for the catalytic oxidation process was ca. 90 kJ mol-1.  相似文献   

15.
Liquid phase benzylation of benzene by benzyl chloride to diphenyl methane over InCl3, GaCl3, FeCl3 and ZnCl2 supported on commercial clays (viz. Montmorillonite-K10, Montmorillonite-KSF and Kaolin) or on high silica mesoporous MCM-41 (at 60, 70 and 80 °C) has been investigated. The supported InCl3, GaCl3 and FeCl3 showed high activity for the benzylation of benzene. The redox function created due to the impregnation of the clays or Si-MCM-41 by InCl3, GaCl3, FeCl3 or ZnCl2 seems to play a very important role in the benzylation process. Among the catalysts, the InCl3/Mont.-K10 showed both high activity and high selectivity for the benzylation. The activity of this catalyst for the benzylation of different aromatic compounds is in the following order: benzene>toluene>mesitylene>anisole. The InCl3 (or GaCl3)/Mont.-K10 (or Si-MCM-41) catalyst showed high benzene benzylation activity even in the presence of moisture in the reaction mixture. The catalyst can also be reused in the benzylation for several times. Kinetics of the benzene benzylation (using excess of benzene) over the supported metal chloride catalysts have also been thoroughly investigated. A plausible reaction mechanism for the benzylation over the supported metal chloride catalysts is proposed.  相似文献   

16.
17.
Solid electrolyte membrane reactors (SEMRs) have been used to both study and influence catalytic reaction rates. Methane coupling is the reaction most thoroughly and intensively studied in these membrane reactors. In the last 20 years, oxygen ion (O2−), proton (H+) and mixed (O2−-e, H+-e) conducting membranes have been tested in order to maximize the conversion of methane to C2 compounds. The present review contains the fundamental operating principles of the various SEMR types and their applications in this reaction. The difficulties that should be overcome in order to promote this SEMR process to an industrial scale are discussed.  相似文献   

18.
Lower loading of Fe (1 wt%) and higher reaction temperature (450 °C) led to higher and stable selectivity of C3+ olefins by ethanol conversion using Fe/H-ZSM-5 catalysts. Carbon deposition and framework collapse of zeolite support, which may be the cause of change in selectivity of products, was suppressed in some degree.  相似文献   

19.
The simultaneous reduction of N2O+NO with carbon supported Ni/K catalysts was studied. High conversions of both compounds were obtained at 400°C, and a synergystic effect between Ni and K was observed. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

20.
Performance of In- and Ga-modified ZSM-5 type zeolites (namely, In2O3/H-ZSM-5, Ga2O3/H-ZSM-5, H-GaMFI and H-GaAlMFI) and InCl3 or GaCl3 supported on high silica mesoporous MCM-41 or on Mont.-K10 in the liquid phase polycondensation of benzyl chloride to polybenzyl has been investigated. Influence of solvent (namely, dichloroethane, n-heptane and ethanol) and temperature on the rate of polycondensation of benzyl chloride over the catalyst (InCl3/Si-MCM-41) showing highest polycondensation activity has also been studied. The In- and Ga-containing solid catalysts show good or high activity in the polycondensation reaction at the reaction condition normally employed in the benzylation of aromatic compounds by benzyl chloride. However, the polycondensation is strongly influenced by the solubility of the polybenzyl polymer in the reaction medium and consequently by the solvent used as the reaction medium.  相似文献   

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