共查询到20条相似文献,搜索用时 70 毫秒
1.
2.
四氢萘是多环芳烃加氢转化的产物或者中间体,其加氢裂解行为和规律的研究在重芳烃转化和脱除领域有着重要的意义。采用等体积浸渍法制备得到了氧化铝负载贵金属(Pt,Ir和Pd)催化剂和酸性分子筛(MOR和ZSM-5)负载铂双功能催化剂,考察了它们催化四氢萘加氢裂解的反应行为。氧化铝为载体时金属催化剂表面主要发生加氢及脱氢反应,其中金属Pt表现出最高的加氢和脱氢活性。双功能催化剂上四氢萘发生加氢裂化、异构化、氢转移及烷基化等复杂反应,金属Pt通过氢溢流作用提高了分子筛Br?nsted酸活性从而提高催化剂加氢裂解活性和选择性,但过量金属Pt会加剧苯环加氢而不利于单环芳烃的生成。分子筛孔道的限域作用对四氢萘的反应活性及产物分布有重要影响,相比Pt/ZSM-5催化剂,Pt/MOR表现出更高的裂解活性及异构化选择性。Pt/MOR催化剂上四氢萘加氢裂解主要通过异构-裂解路径进行,异构化活性及异构体构型决定了裂解活性及产物的分布。 相似文献
3.
4.
5.
以无定型硅铝分子筛(ASA)作为载体,以P和B作为助剂,按照P、B引入的不同方式采用等体积浸渍法制备了4种加氢催化剂NiMo、NiMoP-2、NiMoB-5和NiMoP-2B-5,在固定床反应器上,以萘作为反应原料研究助剂P和B引入对催化剂结构和加氢性能的影响,并利用XRD、NH3-TPD表征手段对催化剂进行表征.结果... 相似文献
6.
7.
采用H_2-TPD表征加氢改质催化剂上氢溢流效应,并考察氢溢流效应与柴油加氢改质催化剂性能的关联性,研究分子筛含量对加氢改质催化剂性能的影响和加氢改质催化剂的吸附-脱附氢性能,结果表明,分子筛不仅是催化剂的酸中心,而且对催化剂的加氢-脱氢性能有影响,催化剂的吸附氢量与柴油十六烷值提高值有良好的对应关系,说明催化剂的吸附氢量越高,其加氢性能越好,表明加氢功能与酸功能的良好匹配能够有效改善催化剂的加氢性能,金属组分能够决定加氢性能,加氢性能也会受分子筛的影响。 相似文献
8.
9.
四氢萘加氢裂化反应动力学 总被引:1,自引:0,他引:1
在连续流动的微反装置上,研究了四氢萘加氢裂化反应动力学,探讨了加氢裂化催化剂活性中心与反应表现活化能的关系。结果表明,四氢萘加的氢裂化反应为拟一级反应。在8.5MPa时,其表观活化能为132.748kJ.mol^-1。在6.5MPa时,当反应温度高于360℃,强酸中心与弱酸中心同时活化,活化能从87.274kJ.mol^-1提高到103.276kJ.mol^-1。 相似文献
10.
以纳米Fe_2O_3为催化剂,在0.5 L高压釜中考察了反应压力19 MPa下,不同反应温度(435℃~465℃)和反应时间(0 min~120 min)对萘-四氢萘体系加氢转化过程及产物分布的影响。根据实验结果和分析,建立了萘-四氢萘体系加氢转化反应机理模型,通过优化算法求解得到各反应的反应速率常数和活化能。结果表明:萘很快达到转化平衡状态,且低温和长停留时间有利于萘的加氢转化;萘的加氢反应速率高于四氢萘的脱氢反应速率,在四氢萘的加氢反应中,以异构化反应为主,主要生成甲基茚满和丁基苯。反应物萘、四氢萘、十氢萘(反)、十氢萘(顺)、1-甲基茚满、正丁基苯和烷基苯的质量分数的实验值和模拟值的相对偏差分别为4.56%,1.35%,9.60%,7.24%,8.29%,10.64%和10.07%。 相似文献
11.
12.
酶催化剂具有高效性,多样性,底物专一性,区域选择性、化学选择性、对映选择性以及反应条件温和的特点。而酶的固定化后除了保持原有的特点外,易与反应物和产物分离,可回收重复使用,降低生产成本。本文对酶催化剂的固定化方法以及在有机催化反应中的应用作了部分简述。并对固定化方法进行了比较和评价。 相似文献
13.
14.
纳米金催化剂研究进展 总被引:2,自引:0,他引:2
比较详细的介绍了金催化剂的应用研究情况.尤其对CO的常温脱除、富氢条件下CO的选择性氧化.邻二醇的选择性氧化以及烃类的选择性氧化等反应过程进行了较为详细的介绍,具有一定的参考价值。 相似文献
15.
Siriporn Jongpatiwut Nitchanun Rattanapuchapong Thirasak Rirksomboon Somchai Osuwan Daniel E. Resasco 《Catalysis Letters》2008,122(3-4):214-222
A series of mono- and bi-metallic Pt-Pd/Al2O3 samples with and without F were studied as aromatic hydrogenation catalysts. The effects of changing the order of impregnation
of the Pt precursor and F as well as varying the calcination temperature (300–500 °C) were investigated. Temperature programmed
reduction (TPR) results demonstrate the presence of a higher fraction of dispersed metal precursor species left on the surface
from the impregnation (PtO
x
Cl
y
) on the Pt/Al2O3 sample calcined at high temperature. The impregnation of F before the Pt precursor significantly decreases the interaction
between the metal and the support. However, this decrease is not observed when F is impregnated after the metal precursor.
For the bimetallic Pt-Pd catalysts, the sample prepared adding F before the metal show a higher degree of Pt-Pd interaction
than either the parent Pt-Pd/Al2O3 catalyst or the one prepared with F added later. TPD of ammonia result show the increase in strong acid sites when F is present.
Activity tests for tetralin hydrogenation in the presence of 350 ppm dibenzothiophene indicate a better sulfur tolerance for
all F-promoted catalysts, especially Pt-Pd. 相似文献
16.
Carina Heisig Jelka Diedenhoven Christopher Jensen Helmut Gehrke Thomas Turek 《化学工程与技术》2020,43(3):484-492
The conversion of bio-based succinic acid (SA) to the value-added chemicals 1,4-butanediol (BDO), γ-butyrolactone (GBL), and tetrahydrofuran (THF) can replace the corresponding petrochemical production routes to achieve a sustainable process. The reaction network for aqueous-phase catalytic hydrogenation of succinic acid over a supported Re-Pd catalyst was identified and the reaction kinetics was determined. With the developed kinetic model, the composition of the product mixture regarding the desired products (BDO, GBL, THF) can be described as a function of educt concentration, temperature, and pressure. The maximum BDO yield was achieved at high pressure and low temperature, while low pressure and high temperature favored GBL and THF production. 相似文献
17.
用XRD、TG-DTG、CO-TPD和H2-TPD等技术, 对三种Cu-Fe催化剂的物相、还原和程序升温脱附行为进行研究, 发现不同制备方法得到的CuO-Fe2O3复合体系间存在着不同的相互作用。高温焙烧后形成化合物CuFe2O4, 浸渍型样品使得CO在表面的吸附中心均匀化。不同的相互作用导致CO和H2的吸附中心种类、相对数量发生变化求得了各类脱附中心的反应级数n和活化能Ed。 相似文献
18.
Heidi Markus Päivi Mäki-Arvela Narendra Kumar Natalya V. Kul’kova Patrik Eklund Rainer Sjöholm Bjarne Holmbom Tapio Salmi Dmitry Yu. Murzin 《Catalysis Letters》2005,103(1-2):125-131
The natural lignan hydroxymatairesinol was hydrogenolysed to a potential anticarcinogenic substance matairesinol over different carbon-supported palladium catalysts. The reaction was conducted in 2-propanol at 70 °C under hydrogen flow in a stirred glass reactor. The catalysts were characterised by N2-physisorption, CO pulse chemisorption and pH measurement of aqueous catalyst slurries. The most active catalyst (Degussa-Hüls) gave yields of matairesinol over 90% in 4 h. It was concluded that the acidity of the catalyst had a profound influence on the reaction rate. 相似文献
19.
研究了负载在Al2O3载体上的贵金属钯(Pd)基催化剂在裂解C5馏分中选择性加氢反应中的性能。结果表明,Pd/Al2O3催化剂上可进行选择性加氢的反应条件区域为压力0.5~1.0MPa、体积空速2—4h^-1、氢油体积比100:1~300:1和反应温度为55—65℃,在此反应条件下,炔烃能被完全加氢去除,同时二烯烃发生部分转化,转化产物主要为单烯烃,其中二烯烃转化的产物主要是热力学相对稳定的单烯烃;在选定的反应条件中,随温度升高、压力增加、氢油比增加,炔烃、二烯烃转化率提高;而随液时空速增加,二烯烃转化率有所下降;在各反应条件中,温度和压力对催化剂加氢性能影响较为显著;制备的Pd/Al2O3催化剂对于炔烃和二烯烃具有好的选择性加氢能力,可能原因一方面是由于反应条件选择较缓和,另一方面是原料中硫的存在。 相似文献
20.
《Catalysis Reviews》2007,49(1):1-32
The production of organic oxygenates by partial oxidation on oxidic catalysts is of considerable industrial importance. Excellent selectivities and yields are often obtained in multitubular reactors due to high performance catalysts. However, there are several processes, e.g., the production of maleic anhydride and phthalic anhydride, where the product yield could be enhanced and improvements are desirable. Various reaction engineering concepts are proposed for that purpose, from reactor structuring to electrochemical promotion. In this article, the actual state of these efforts, which are often at the very beginning, is reviewed. 相似文献