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分别以改性Beta分子筛、ZSM-5分子筛以及两者按不同比例复配的分子筛作为载体的酸性组分,采用等体积浸渍法制备Ni-Mo-P型加氢裂化催化剂,分别记为CAT-B、CAT-Z、CAT-BZ。利用BET比表面积测定、X射线衍射(XRD)、氨程序升温脱附(NH3-TPD)、吡啶吸附红外光谱(Py-IR)及氢程序升温还原(H2-TPR)等技术手段对催化剂样品进行系列表征分析。以四氢萘为模型化合物,在固定床连续加氢装置上考察制备的分子筛型加氢裂化催化剂的反应性能。研究结果表明:改性Beta分子筛和ZSM-5分子筛复配的催化剂CAT-BZ-3具有较适宜的比表面积和孔结构,相比于催化剂CAT-B和CAT-Z具有优异的酸量和酸强度,并且其表面的活性金属易于还原,在载体上的分散性较好。对催化剂进行活性评价认为,分子筛复配制得的催化剂具有较高的四氢萘加氢裂化催化活性,其中催化剂CAT-BZ-3的四氢萘转化率及BTX选择性最高。 相似文献
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以钛酸四丁酯为前驱体,乙醇为溶剂,通过浸渍法制备了一系列TiO_2改性MCM-22微孔分子筛择形催化剂,在连续流动固定床反应器上考察了甲苯与碳酸二甲酯烷基化合成对二甲苯的择型催化性能。通过XRD、FT-IR、N2吸附-脱附、NH_3-TPD、XPS、吡啶吸附FT-IR、UV-Vis等手段对催化剂进行表征,并考察了反应温度、空速对甲苯烷基化反应的影响。结果表明,制备的TiO_2改性MCM-22催化剂在甲苯与碳酸二甲酯烷基化合成对二甲苯过程中不仅表现出优异的择型性能,而且还保持了较高的催化活性。这是由于钛酸四丁酯具有较大的分子尺寸,在浸渍过程中仅微孔分子筛外表面酸性位被有效覆盖,而分子筛孔内的酸性位并未受到影响。 相似文献
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《天津化工》2015,(4)
本文以丁二酸、丁二酸酐和1,4-丁二醇为原料,以自制的微孔钛硅分子筛为聚合催化剂,制备了高相对分子质量的聚丁二酸丁二醇酯。考察了原料物质的量比、酯化时间、酯化温度对酯化反应的影响,以及缩聚时间、缩聚温度、分子筛种类和用量对聚丁二酸丁二醇酯性能的影响。结果表明,当丁二酸、丁二酸酐和丁二醇的物质的量比为0.5:0.5:1.3,酯化温度为150℃,反应2.5 h酯化率达到95.2%;当以制备的钛硅分子筛为缩聚催化剂,其用量为酯化产物总质量的1%,缩聚温度为220℃,反应3 h,产物聚丁二酸丁二醇酯的特性粘度可以达到2.0 d L/g,相对分子质量可以达到12.9万g/mol以上。 相似文献
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合成了3种不同晶粒尺寸的ZSM-5分子筛,并制得MTP催化剂,对ZSM-5分子筛催化剂在MTP反应中的性能进行系统研究。采用XRD、SEM、N2物理吸附和TGA等对ZSM-5分子筛催化剂进行表征,发现小晶粒的ZSM-5分子筛具有良好的抗积炭性能,在MTP反应中具有较高的稳定性。采用小晶粒分子筛制成的催化剂,考察反应工艺条件对催化剂催化性能的影响,结果表明,丙烯选择性随反应温度和空速提高而增加,降低反应压力和提高水醇质量比也有利于提高丙烯选择性,为调整MTP工艺的产物分布和优化反应工艺条件提供了技术依据。 相似文献
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利用改性HZSM—5分子筛催化剂,催化合成了苯乙酸苄酯、苯乙酸苯乙酯、苯乙酸茴香酯,对影响反应的诸因素进行了讨论。 相似文献
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Cu-MCM-41催化剂的制备及在草酸酯加氢制乙二醇催化性能 总被引:1,自引:0,他引:1
采用蒸氨沉淀法制备了Cu-MCM-41分子筛催化剂,并采用BET、TEM、XRD和TPR等表征手段对该催化剂进行了表征。表征结果说明所研制催化剂具有规整有序的介孔结构并且活性组分铜得到了良好的分散。通过对该催化剂在草酸二甲酯(DMO)加氢制乙二醇反应中反应性能的研究发现,反应温度、反应压力、氢酯比和液时空速等工艺参数均对催化活性产生重要影响。结果表明,Cu-MCM-41催化剂在反应温度473 K,反应压力2.5 MPa,n(氢)∶n(酯)为80~100时表现出最佳的加氢反应性能,液时空速在2.0 h-1时,DMO仍然可以完全转化并且乙二醇(EG)选择性达到98%以上。 相似文献
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以含改性HY分子筛的TiO2-SiO2复合氧化物为载体,以Ni、W为活性金属组分,采用等体积溶液浸渍法制得了焦化蜡油加氢处理催化剂,考察了浸渍液中加入柠檬酸对催化剂性质及加氢精制性能的影响。BET、FT-IR、XRD、UV-Vis DRS和TG-DSC等表征结果表明,柠檬酸与金属组分间的络合作用提高了金属活性组分的分散度,改变了金属组分的存在状态,促进了单一形式的聚钨酸盐和高活性的六配位八面体Ni物种的形成。柠檬酸改性的Ni-W系催化剂对焦化蜡油的加氢精制性能明显改善,尤其是加氢脱氮性能得以大幅度提高。 相似文献
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Takeshige Takahashi Mohammad Noor Alsadat Nasution Takami Kai 《Applied Catalysis A: General》2001,210(1-2)
The vapor phase Beckmann rearrangement of cyclohexanone oxime (CHO) over solid acid catalysts including zeolites was carried out to elucidate the effects of the acid strength and the micropore size of the catalysts on the selectivity of -caprolactam (CL) and the catalyst deactivation rate. It was found that the catalyst deactivation rate was strongly dependent on the acid strength of the acid catalysts. The improvement of catalyst life was achieved by using MFI-type metallosilicates having weak acid sites. The CL selectivity decreased over the acid catalysts with micropores larger than those of the MFI zeolites. Furthermore, using methanol and carbon dioxide as the diluent solvent and diluent gas improved CL selectivity and catalyst life, respectively. 相似文献
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Vapour-phase reactions of, in situ, prepared formaldehyde with methyl propionate were studied using X, Y and ZSM-5 zeolite catalysts. Base properties of these zeolites were enhanced by KOH or NaN3 treatment. The niobium and molybdenum ZSM-5 zeolite supported oxides were also tested for their catalytic activity. The results are discussed in terms of an ability of zeolite catalysts to synthesize methyl methacrylate. 相似文献
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以四丙基氢氧化铵为模板剂,碱性有机生物分子L-Lysine为添加剂,水热合成系列不同硅铝物质的量比的纳米HZSM-5分子筛,结合XRD、SEM、Py-FTIR和N2吸附-脱附技术,探讨分子筛结构形态、酸性与其在乙酸和丁醇酯化反应中的催化性能关系。结果表明,纳米HZSM-5分子筛催化剂的酸性位与比表面积、孔径和孔容等结构形态间存在协同作用,共同决定最终的催化效果;在反应温度125℃、乙酸用量0.125 mol、醇酸物质的量比2∶1、带水剂苯用量为10 m L、催化剂用量0.4 g和反应时间4.5 h条件下,乙酸转化率93.65%,乙酸丁酯选择性大于97%。催化剂重复使用6次,乙酸转化率仍大于90%,重复使用性能较好。 相似文献
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Background and strategy of catalyst development for upgrading aromatic hydrocarbons are intensively discussed. Originally prepared catalysts (hydrogenation and hydrocracking catalysts) were used for accelerated aging tests. Though each catalyst showed superior catalytic performance as compared to commercially available catalysts, a severe deactivation was observed on the hydrocracking (HC) catalysts. A new type of HC catalyst was designed and prepared, based on the understanding of catalyst deactivation. High silica NaY zeolites were synthesized using crown-ether. USY zeolites were then prepared by ion exchange, steaming and calcining. Surface properties and catalytic functions of well-crystallized USY zeolites were investigated to develop practical HC catalysts. The Ni–W catalyst prepared using the newly prepared USY zeolite showed a considerable improvement in the HC activity. 相似文献
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Elena I. Basaldella Julio C. Paladino Mariana Solari Graciela M. Valle 《Applied catalysis. B, Environmental》2006,66(3-4):186-191
The utilization of exhausted fluid catalytic cracking (FCC) catalysts as raw materials for the zeolite synthesis was analyzed. Samples of the catalysts directly released from FCC units and the corresponding impact grinding pretreated samples were used. Mechanical treatment was observed to decrease catalyst crystallinity and particle size. The catalyst reactivity was analyzed in terms of conversion in zeolite and product properties. Hydrothermal synthesis experiments in NaOH medium were performed. Catalysts conversion in A and X type zeolites was obtained for treated and not treated samples. In particular, high conversion in NaX type were achieved using the more siliceous catalyst, whereas grinding activation produces a decrease of particle size and Al/Si ratio of the zeolites obtained. 相似文献
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