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二异丙苯和苯烷基转移反应中Y型沸石催化剂的研究 总被引:1,自引:0,他引:1
采用水热处理与离子交换结合的方法对NaY沸石进行了改性,XRD、XPS及孔结构测试结果表明,NaY沸石经水热处理和离子交换改性制得的Y沸石催化剂的晶体晶型未发生变化;处理温度对催化剂的相对结晶度、孔结构及比表面积有很大影响;水热处理可以使微孔孔口啼生缺陷或破裂;在一定温度下,催化剂能够形成二次孔;过高的处理温度将导致催化忆结构的崩坍,Y沸石催化剂存在铝富集在表面的现象,采用左外光谱及哟啶,2,6- 相似文献
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Y沸石脱铝有多种方法。由于在脱铝过程中发生水解、聚合、重排等反应,分子筛的孔结构将发生很大的变化,如形成空穴,甚至可导致骨架结构单元的崩塌,形成二次孔。由于不同的脱铝方法的脱铝机理不同,即使它们的脱铝程度一致,产生的孔结构也将不同,这必将导致它们的酸性质和催化性能的差异。目前关于Y沸石孔结构的研究报导还很少,尤其对SSY,US-SSY沸石孔结构的报导更为鲜见。本文用低温N_2吸附-脱附等温线和层厚t等方法,对四种不同方法制备的脱铝Y沸石(USY,DAY,SSY和US-SSY)的微孔、二次孔及其孔径分布(2.0~60.0nm)进行了初步研究,得到了一些有用的信息,为进一步研究其酸性质和催化性能打下了基础。 相似文献
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采用水热、草酸脱铝及表面活性剂存在下的水热晶化相结合的组合法对Y型分子筛进行了改性, 考察了表面活性剂十六烷基三甲基溴化铵(CTAB)存在下的CTAB加入量对Y型分子筛相对结晶度(Xc)、晶胞常数(a0)、硅铝比、比表面积、孔结构及加氢裂化性能的影响, 并利用NH3-TPD对改性Y型分子筛进行了酸性表征。结果表明, 少量的CTAB就可以使Y型分子筛的相对结晶度从37.9%提高到68.3%, 硅铝比从7.72增大到9.32, a0从2.4534nm减小到2.4485nm, 介孔的孔体积从0.157mL/g提高到0.180mL/g以上,且总酸酸量降低。VGO的加氢裂化反应结果表明,CTAB存在下改性Y型分子筛的加氢裂化活性和中间馏分油收率比工业催化剂分别高2.42%和4.20%。 相似文献
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用低温氮物理吸附法研究了化学法和水热法相结合制备的两个系列Y沸石的孔结构性质。研究结果表明, 用不同化学试剂处理Y沸石形成的孔结构有明显差别。但是, 当把由此得到的Y沸石在相同条件下交替进行水热处理和化学处理时, 孔结构却呈现类似的变化趋势, 即总比表面积、微孔比表面积和微孔体积是先下降后上升, 经第二次水热和化学处理是再次下降再次回升。而过程中产生的“二次孔”比表面积却呈现先上升后下降, 又回升又下降的相反的变化趋势。这种变化趋势, 可能与水热处理和化学处理过程中非骨架铝物种的形成与消失有关。 相似文献
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含金属Y型沸石的合成,表征及其催化性能研究 总被引:3,自引:3,他引:0
在水热合成体系中制备了系列含金属的Y型沸石(金属=铁、铬、钴),并采用XRD、SEM、ICP、FTIR和UV-vis技术对其进行了表征。FTIR和UV-vis测试结果表明Fe(Ⅲ)、Co(Ⅱ)和Mn(Ⅱ)离子进入沸石骨架,而Cr(Ⅲ)则没有。金属离子对所制备产物晶化及组成有很大的影响。此外,还对含金属的Y型沸石在环己烷氧化反应中的催化性能进行了考察。 相似文献
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系统研究了以KOH为结构导向剂,Y型沸石(HY和NaY)在水热条件下转晶为MER型沸石的行为.MER型沸石是硅铝比(Si/Al)在2~3之间且具有四种尺寸8元环孔道(3.1Å×3.5Å,2.7Å×3.6Å,3.4Å×5.1Å,3.3Å×3.3Å)的硅铝沸石分子筛,在小分子催化以及分离方面具有重要的潜在应用.传统水热法合成高结晶度MER型沸石需要7~10 d,将Y型沸石置于KOH的溶液中,经水热处理可在2 d内生成高结晶度的MER型沸石,而水热处理具有等价摩尔组成的无定形硅铝凝胶则得不到高结晶度MER型沸石的纯相.HY沸石可在100和150℃发生转晶,而NaY则只能在150℃发生转晶.KOH/SiO2比和H2O/SiO2比对Y型沸石的转晶行为有重大的影响,只有在最优KOH/SiO2比和H2O/SiO2比条件下才能生成高结晶度的MER型沸石.该转晶合成法显著缩短了MER型沸石的合成周期,对缩短其它有重大工业应用价值的沸石分子筛的合成周期有重要的借鉴意义. 相似文献
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采用四丙基氢氧化铵和氢氧化钠有机无机混合碱TPAOH/NaOH体系对ZSM-5分子筛进行改性处理,得到了具有介孔和微孔的ZSM-5分子筛。用XRD、N2吸附脱附、NH3-TPD、SEM等手段对改性后的产物进行表征。结果表明,碱处理ZSM-5分子筛会使分子筛同时脱硅和脱铝。当混合碱体系中总OH-浓度一定时,随TPA+/OH-比值的降低和处理时间的延长,均会使分子筛的微孔结构数量减少,介孔结构数量增加。同时,还会改变分子筛的酸性,TPA+/OH-比值适合的混合碱体系可在生成介孔的同时最大限度保留微孔结构,并减少分子筛的强酸数量,在甲醇制烯烃反应(MTO)中表现出较高的丙烯选择性。与无机碱NaOH相比,TPAOH对分子筛的改性速率较慢而且温和,具有可控性,可以起到孔道生长调节剂的作用。 相似文献
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Hailiang Yin Tongna Zhou Yunqi Liu Yongming Chai Chenguang Liu State Key Laboratory of Heavy Oil Processing Key Laboratory of Catalysis CNPC China University of Petroleum Qingdao Sh ong China 《天然气化学杂志》2011,(4):441-448
Two mixed-matrix NiMo/Al2O3 catalysts containing nano-and micro-sized zeolite Y have been prepared to explore the size effect of zeolite Y particle on the hydrodesulfurization(HDS)and hydrodenitrogenation(HDN)activities of fluid catalytic cracking(FCC)diesel.They were characterized by SEM,BET,XRD,H2-TPR,NH3-TPD and HRTEM.The results show that the catalyst containing nano-sized zeolite Y possesses larger average pore diameter,higher pore volume,weaker and lesser acid sites,more easily reducible metal phases,shorter MoS2 slabs and more slab layers than the catalyst containing micro-sized zeolite Y.The catalysts were also evaluated with a high-pressure fixed-bed reactor using real FCC diesel as feed.The results display that the catalyst containing nano-sized zeolite Y bears higher HDS and HDN activities and exhibits higher relative rate constant for the removal of total sulfur or nitrogen than the one containing micro-sized zeolite. 相似文献
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采用溶胶-凝胶结合CO2超临界干燥的方法制备了钛硅复合氧化物(CTS)载体基质材料。以不同方法将Y型分子筛与CTS混合制得Y/CTS复合载体,以Ni、W为活性金属组分,采用等体积溶液浸渍法制备了加氢处理催化剂。考察了Y型分子筛与CTS的复合方式及加入量对催化剂加氢精制性能的影响,进而研究了P改性对Y/CTS结构及酸性的影响。结果表明,Y型分子筛的加入提高了CTS复合氧化物的酸性和比表面积,适当的分子筛加入量没有破坏CTS原有的结构。当Y型分子筛的加入量大于20%,Y/CTS的总酸量高于CTS,尤其是B酸量提高幅度较大, B酸强度也明显增加;Y/CTS载体中加入P以后,载体的总酸量增加,L酸的比例提高。以胜利焦化蜡油为原料,对催化剂的加氢反应性能评价结果表明,Y型分子筛的加入以及P对Y/CTS的改性,能够在一定程度上提高催化剂的加氢脱硫和加氢脱氮活性。 相似文献
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Kevin R. Franklin Gisela Heidecker Barrie M. Lowe Gordon S. Stove 《Journal of inclusion phenomena and macrocyclic chemistry》1990,8(3):289-297
The sorption of galactose by Na-Y, K-Y and Ba-Y zeolites has been investigated by isopiestic equilibration at 25°C. The equilibrium galactose and water contents of the zeolites were determined for water activitiesa
w in the range 0.111 <a
w < 0.98. It was found that the maximum uptake of galactose U
0
G
(observed fora
W 0) was highest for Na-Y and least for Ba-Y. In contrast at high water activities the galactose uptake was highest for Ba-Y and least for Na-Y. 相似文献
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采用原位包覆技术制备了无定形硅铝(ASA)包覆Y型分子筛的Y/ASA复合材料。分别以Y/ASA复合材料和工业Y分子筛与ASA的机械混合材料Y-ASA为载体,Ni-W为活性组分,制备了两种负载型催化剂,并考察了两种催化剂的加氢裂化性能,通过XRD、SEM、吸附吡啶的原位红外光谱和N2吸附-脱附对载体和催化剂进行了表征。结果表明,Y/ASA载体和Ni-W/Y/ASA的总酸量较低,但强酸量和强弱酸比例均高于Y-ASA和Ni-W/Y-ASA,Y/ASA载体和Ni-W/Y/ASA催化剂拥有更大的介孔比表面积、孔容及平均孔径。正癸烷的加氢裂化反应结果表明,Ni-W/Y/ASA催化剂上正癸烷的转化率和中间组分(C5~9)收率比Ni-W/Y-ASA催化剂分别高7.6 %和12.4 %。 相似文献
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Zeolite Y modified by cesium and magnesium ions was prepared by ion-exchange and impregnation methods, and its activity in the cyanoethylation of aliphatic and aromatic alcohols and amines was investigated. During the preparation of some samples, the transformation of zeolite Y into a pollucite-type phase occurred. This phase exhibited good activity in the cyanoethylation of aliphatic alcohols. The prepared solids modified by the impregnation method were more active than the ion-exchanged solids. The activities of the catalysts, in contrast to other basic solids, were scarcely affected by the presence of air or moisture. A correlation between catalyst basicity and catalytic activity is discussed. The catalysts were characterized by X-ray diffraction, volumetric nitrogen adsorption surface area measurement, and CO2 temperature-programmed desorption. Scanning electron microscopy revealed that the particles of the modified nanocatalysts were < 40 nm. The reaction of acrylonitrile with linear alcohols in the presence of the catalysts was accelerated by microwave irradiation. 相似文献
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N.G. Grigorieva S.A. Kostyleva S.V. Bubennov V.R. Bikbaeva A.R. Gataulin N.A. Filippova A.N. Khazipova T.R. Prosochkina B.I. Kutepov Narender Nama 《Journal of Saudi Chemical Society》2019,23(4):452-460
High activity and selectivity of the hierarchical H-Ymmm zeolite in the synthesis of practically important pyridines (by interaction of C2–C4 alcohols with formaldehyde and ammonia, cyclocondensation of acetaldehyde and propanal with ammonia), dialkyl quinolines (by reaction of aniline with aldehydes) and alkyl dihydroquinolines (by reaction of aniline with ketones- acetone, acetophenone) were revealed in the research.The advantages of the micro-meso-macroporous H-Ymmm zeolite over the microporous H-Y zeolite in the synthesis of pyridines and quinolines were demonstrated. In the products formed by the reaction of ethanol with formaldehyde and ammonia, picolines (up to 63%) and lutidine are predominant in H-Ymmm, Pb-H-Ymmm and Fe-H-Ymmm zeolites. The interaction of n-propanol (n-butanol) with formaldehyde and ammonia in the presence of H-Ymmm zeolite with high selectivity produced 3,5-lutidine (up to 90%) or 3,5-diethylpyridine (85%). H-Ymmm zeolite makes it possible to prepare 2-methyl-5-ethylpyridine with 87% selectivity (reaction of acetaldehyde with ammonia) and 2-ethyl-3,5-dimethylpyridine with 58% selectivity (reaction of propanal with ammonia).The synthesis of dialkylquinolines and dialkyltetrahydroquinolines with a total selectivity of 65–73% by the interaction of aniline with C3–C5 aldehydes has been carried out. The dihydroquinoline derivatives with the selectivity of up to 70% have been synthesized by the reaction of aniline with ketones (acetone, acetophenone). 相似文献
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水溶性分散型加氢催化剂催化作用的研究 总被引:17,自引:2,他引:17
以克拉玛依减压蜡油(VGO)为反应体系,对以水溶性分散型催化剂为催化体系的渣油加氢裂化过程外甩催化剂进行了分离和分析,发现单组分催化剂在反应过程中分别是以NiS(Ni7S6)、MoS2和Fe1-xS的形式存在。以二苯甲烷和克拉玛依VGO为模型化合物和反应原料,对钼、镍、铁元素单组分催化剂催化性能的研究结果表明,硫化态金属催化剂产生氢自由基中间体氢化不饱和键的“氢化活性”不同,钼催化剂明显优于镍催化剂,镍催化剂优于铁催化剂;不同催化剂抑制大分子自由基之间缩合生焦的能力也不相同,钼催化剂的抑焦能力最强,镍催化剂次之,铁催化剂的抑焦能力较差。 相似文献