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21.
The catalysts of CeO2 and the mixture of CeO2 and CuO were prepared, and the activities of these catalysts for completely oxidizing benzene were studied.The results show that the optimal proportion of CeO2/CuO is 6: 4.The highest temperature at which benzene was completely oxidized on these catalysts at different airspeed was measured.Compared these catalysts with the noble metal used, our catalysts had superiority in the resources and the industrial cost besides good activities. 相似文献
22.
Burcu Selen alayan Ahmet K. Avc Z. lsen
nsan A. Erhan Aksoylu 《Applied Catalysis A: General》2005,280(2):181-188
Indirect partial oxidation (IPOX) of propane was studied over bimetallic 0.2 wt.% Pt–15 wt.% Ni/δ-Al2O3 catalyst in the 623–743 K temperature range. The unreduced and reduced forms of the catalyst were characterized by ESEM–EDAX and X-ray diffraction (XRD). In the IPOX tests, the effects of steam to carbon ratio (S/C), carbon to oxygen ratio (C/O2) and residence time (W/F (gcat h/mol HC)) on the hydrogen production activity, selectivity and product distribution were studied in detail. The effect of temperature program applied (increasing from 623 to 743 K, ITP; decreasing from 743 to 623 K, DTP) during reaction was also tested. The results showed that the Pt–Ni bimetallic system has superior performance characteristics compared to the monometallic catalysts reported in literature. The reason is thought to be the utilization of the catalyst particles as micro heat exchangers during IPOX; the heat generated by Pt sites during exothermic total oxidation (TOX) being readily transferred through the catalyst particles acting as micro heat exchangers to the Ni sites, which promote endothermic steam reforming (SR). The optimal conditions were found as S/C = 3, C/O2 = 2.70 and W/F = 0.51 gcat h/mol HC for IPOX of propane on the basis of high hydrogen productivity and selectivity between 623 and 748 K for the experimental conditions tested. The thermo-neutral points obtained showed the sustainability of reaction in terms of energy. 相似文献
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A. Andreev L. Prahov M. Gabrovska A. Eliyas V. Ivanova 《Applied catalysis. B, Environmental》1996,8(4):365-373
The catalytic activity of a wide range of transition metal oxides in oxidation of sulphide ions by air in aqueous medium was studied. Some specific features of the reaction mechanism on some of the studied oxides were considered. The transition metal oxides are promising catalysts for practical application. Some of these oxides will allow the preparation of catalysts possessing activity comparable to that of the cobalt phthalocyanine based catalysts, popular in industrial practice. 相似文献
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Jos M. Moreno Maria A. Aramendía Alberto Marinas Jos M. Marinas Francisco J. Urbano 《Applied catalysis. B, Environmental》2005,59(3-4):275-283
The liquid-phase hydrodechlorination of 3-chloropyridine and chlorobenzene has been studied over alkali-modified zirconia-supported palladium catalysts. The modification of the ZrO2 with alkali metal carbonates improves the catalytic activity of the final palladium catalyst. Therefore, the larger the ionic radii (Li+ < Na+ < K+), the greater the catalytic activity (TOF) of the palladium catalyst. For 3-chloropyridine, hydrodechlorination proceeds without catalyst deactivation. This is explained as the result of the interaction of reaction products (pyridine and HCl) forming pyridinium chloride, thus avoiding the detrimental effect of HCl on the palladium particles. Catalytic hydrodechlorination of chlorobenzene over Pd catalysts exhibits an initial catalytic activity (TOF) much lower than that of 3-chloropyridine and the Pd catalysts deactivate as the reaction proceeds. Finally, chlorobenzene hydrodehalogenation has also been carried out in the presence of an equimolecular amount of pyridine resulting in a decrease in the initial reaction rate on the one hand, but also in an increase in final conversion on the other. 相似文献
28.
以硫酸、磷钨酸、ZRP-5分子筛为催化剂,研究了二甘醇(DEG)脱水环化的反应规律。结果表明,DEG发生分子内脱水环化反应,生成1,4-二氧六环(DOX),DEG分子间脱水不仅可以生成四甘醇、六甘醇等,同时可生成三甘醇、五甘醇等一系列的多甘醇(PEG)。不仅DEG可以脱水环化生成DOX,在反应中生成的PEG也同样可以进行生成DOX的反应。对于二甘醇(DEG)脱水环化反应,硫酸是性能优良的催化剂,反应可以在较低的温度下进行,馏出产物中DOX选择性大于95%。 相似文献
29.
聚丙烯催化剂的研发进展 总被引:5,自引:4,他引:1
综述了用于丙烯聚合的Ziegler-Natta催化剂在给电子体技术及催化剂制备工艺等方面,茂金属催化剂在制备丙烯均聚物、丙烯共聚物及特殊聚丙烯等方面,非茂单活性中心催化剂在丙烯活性聚合、丙烯与极性单体共聚及水介质聚合等方面的研发进展;讨论了聚丙烯催化剂的前景。 相似文献
30.
Modified (α‐diimine)nickel(II) catalysts are suitable for ethylene oligomerization reactions. Due to the mechanism (“chain running”), the formation of double‐bond isomers and branched olefins can be observed. The obtained oligomer mixtures show a Schulz–Flory distribution. Increasing ethylene pressure favors the selectivity of α‐olefin formation. The same effect can be observed when Lewis bases like thiophene or furane are added to the oligomerization reaction mixture. These results can be related to an interaction of the additives with the catalytic active species during the oligomerization process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1356–1361, 2003 相似文献