二氧化硅负载磷钼酸铵催化苯液相硝化反应的研究

以正硅酸乙酯为硅源,采用溶胶-凝胶法制备了负载磷钼杂多酸铵催化剂(S-AMPA),利用XRD、IR以及电位滴定等方法对催化剂进行了表征,并考察了催化剂用量、反应时间和温度等反应参数对催化剂的苯液相硝化反应催化性能的影响.结果表明,溶胶-凝胶法制备的S-AMPA具有典型的Keggin结构,而且负载后催化剂的酸度和酸性点总...     

磷化钼的常压制备及脱硫活性

提出了磷化钼常压制备工艺,包括溶胶-凝胶法制备负载型磷化钼催化剂前体及在常压下以氢氮混合气为还原剂的催化剂前体还原。研究结果表明：磷化钼常压制备工艺可行;担载量为25%、磷钼比为1∶1、焙烧温度为500 ℃、氢氮比为1∶9、还原气空速为2400 h?1、还原终温为550 ℃时催化剂比表面积最大,可达122.336 m2/g;以噻吩为模型化合物考察磷化钼催化剂的催化活性,噻吩转化率可达89.17%。     

二氧化硅载过氧磷钨酸季铵盐催化剂的制备及脱硫性能研究

以正硅酸乙酯为硅源,利用溶胶-凝胶法制备了二氧化硅载过氧磷钨酸季铵盐催化剂,对催化剂进行了XRD分析。以双氧水为氧化剂,苯并噻吩(BT)和二苯并噻吩(DBT)为模型化合物,初步评价了催化剂的氧化脱硫反应性能,并考察了反应时间、催化剂用量以及反应温度等反应条件对BT和DBT的氧化脱除效果的影响。结果表明:常压下,反应温度70℃,反应时间60 min,催化剂用量(w)4%,过氧化氢和模拟油体积比1∶10的条件下,对苯并噻吩和二苯并噻吩的脱除效果最好,脱除率分别达到93.75%和97.13%。催化剂可回收多次使用,仍保持较高活性。     

ZSM-5负载杂多酸催化剂的制备及其氧化脱硫性能研究

以ZSM-5材料为载体,分别采用浸渍法、溶胶凝胶法、水热分散法将杂多酸（磷钼酸、磷钨酸）负载于ZSM-5上制备催化剂。利用X射线衍射、红外光谱、扫描电镜等方法对催化剂进行了表征,发现杂多酸能够高度分散在载体表面。以苯并噻吩为反应物进行氧化脱硫反应,考察了不同合成条件对反应效率的影响。结果表明：水热分散法合成负载磷钨酸催化剂的脱硫效果最好,在反应温度为60℃,负载量为10%,剂油等体积比的最佳反应条件下,脱硫率为73.2%。     

二氧化硅负载磷钼杂多酸铵催化合成环己酮乙二醇缩酮

采用溶胶-凝胶法制备系列二氧化硅负载磷钼杂多酸铵固体酸催化剂,以环己酮和乙二醇为原料、环己烷为带水剂,合成环己酮乙二醇缩酮,考察催化剂负载量、原料配比、催化剂用量、带水剂用量以及反应时间等因素对反应收率的影响。得到较佳工艺条件：n(环己酮)∶n(乙二醇)=1∶1.5,催化剂用量0.5 g,环己烷用量10 mL,回流反应45 min,产品平均收率97.1%。催化剂重复使用性实验结果表明,随着使用次数的增多,二氧化硅负载磷钼杂多酸铵催化剂催化活性下降,但使用6次后,仍表现出较高的缩酮收率。     

反应条件对MoP/TiO2-SiO2-Al2O3催化剂加氢脱氮性能的影响

用溶胶凝胶法制备了不同TiO2含量的MoP/TiO2-SiO2-Al2O3催化剂,对含喹啉的模型化合物,在连续固定床反应器上进行了HDN活性评价,考察了不同反应条件（反应温度、空速、压力、氢油比）对催化剂加氢脱氮性能的影响.结果表明：原位还原法制备的磷化钼催化剂,其加氢活性与原位还原条件有较大的关系,实验确立了最佳加氢脱氮的反应条件为：反应温度为380℃,空速为2.0h^-1,压力为3.0MPa,氢油比为500.     

Mn-Mo/SiO_2催化剂的制备及其催化柴油氧化脱硫

采用溶胶-凝胶法制备锰离子改性的Si O2负载的磷钼酸催化剂,并采用傅里叶红外光谱(FT-IR)、X射线衍射(XRD)和扫描电镜(SEM)等对催化剂进行表征。考察了催化剂用量、过氧化氢用量、反应温度和反应时间等对模型油(苯并噻吩和二苯并噻吩)和直馏柴油氧化脱硫的影响。结果表明:锰离子改性后,催化剂仍然保持了磷钼酸的Keggin型结构,其活性中心的分散度和比表面积均增加;不同反应条件对模型油的氧化脱硫均有影响,且二苯并噻吩(DBT)较苯并噻吩(BT)更易脱除。正交试验结果显示,各因素对柴油脱硫率的影响由大到小依次为反应时间催化剂用量过氧化氢用量反应温度。在催化剂0.15 g,过氧化氢0.25 mL和反应温度70℃的条件下,反应时间4 h后,直馏柴油的脱硫率达90.3%,油品回收率不低于98%。     

甲烷联合重整反应镍基尖晶石催化剂的制备与性能

采用传统浸渍法和溶胶凝胶法分别制备了Ni/MgAl2O4催化剂,并采用氢气程序升温还原(H2-TPR)、X射线衍射(XRD)、透射电镜(TEM)和程序升温脱附(TPD)对催化剂进行表征,考察了催化剂在甲烷联合重整(CSCRM)反应中的催化性能.结果表明:与传统浸渍法制得的Ni催化剂相比,采用溶胶凝胶法制备的Ni/MgAl2O4催化剂中Ni物种与载体之间的作用力更强,在CSCRM反应中表现出更高的催化活性和稳定性.进而,基于溶胶凝胶法探究了Ni/MgAl2O4催化剂中Ni负载量对反应性能的影响,探讨了溶胶凝胶法制备的Ni/MgAl2O4催化剂的构-效关系,为CSCRM反应的非贵金属Ni基催化剂设计与优化提供借鉴.     

AlPW12O40/TiO2催化苯甲醚乙酰化反应

以钛酸丁酯、磷钨酸、硝酸铝为主要原料,采用溶胶-凝胶法制备了AlPW12O40/TiO2复合催化剂.考察了对苯甲醚乙酰化反应制备对甲氧基苯乙酮的催化活性.实验结果表明:AlPW12O40负载量、催化剂用量、反应物配比、反应时间及反应温度等是影响催化效果的重要因素.反应的适宜条件为:AlPW12O40负载量为35％,乙酸酐与苯甲醚物质的量之比为2.5,催化剂用量为反应物总质量的3％,反应温度100℃,反应60 min,苯甲醚转化率可达到84.5％.催化剂易于分离,重复使用仍有较高催化活性.     

活性炭负载型TiO2光催化剂的制备及其光催化活性研究

采用溶胶-凝胶法制备活性炭负载型TiO2光催化剂,用XRD分析了其物相结构.以甲基橙溶液为目标降解物,以紫外灯为光源对活性炭负载型TiO2光催化剂进行了光降解性能的研究,考察了TiO2负载量、催化剂用量、热处理温度等对催化剂的光催化活性的影响.结果表明,当TiO2负载量为33.3%的活性炭负载型TiO2光催化剂用量为2～3 g·L-1、紫外光连续照射5 h时,甲基橙溶液的脱色率可达到96.1%.     

Dibenzothiophene hydrodesulfurization over MoP/SiO<Subscript>2</Subscript> catalyst prepared with sol-gel method

Silica-supported molybdenum phosphide, MoP/SiO₂ catalysts with different Mo weight loadings were prepared by temperature programmed reduction of the oxidic catalyst precursors, which were prepared via sol-gel technique using ethyl silicate-40 as silica source. Samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), BET surface area measurements, and their catalytic activity in hydrodesulfurization (HDS) was tested with dibenzothiophene (DBT) as model compound. XRD analysis revealed the amorphous nature of the catalyst up to 10 wt% Mo loading and the formation of crystalline MoP phase on amorphous silica support with higher Mo loading. BET surface area showed high surface area for catalysts prepared by sol-gel technique with lower Mo content, and the surface area decreased with increasing in Mo loading. The HDS results showed that prepared MoP/SiO₂ exhibited high HDS activity and stability toward the catalytic test. Among the series of catalysts prepared, MoP/SiO₂ containing 20 wt% Mo was found to be the most active catalyst. And the effects of reaction temperature and hydrogen pressure on conversion and product selectivity were investigated.     

Hydrodesulfurization of dibenzothiophene over alumina-supported nickel molybdenum phosphide catalysts

The activity of nickel molybdenum phosphide catalysts was studied for the hydrodesulfurization of dibenzothiophene at 573 K and total pressure of 2.0 MPa. The Al₂O₃-supported NiMo phosphide catalysts were prepared by successive and simultaneous methods. The effect of the reduction temperature on the catalyst activity was also studied. The simultaneous preparation was determined to be the best method for the preparation of the active supported catalyst for dibenzothiophene HDS. The 623 K-reduced catalyst had the highest HDS rate of the catalysts. Nickel migrated from the inside to the surface during the reaction and promoted the HDS activity. The active species in the dibenzothiophene HDS and the oxidation states of Mo, Ni and P in the catalyst before and after reaction and of S after the reaction were studied on the basis of an XPS analysis.     

Influence of reduction temperature and metal loading on the performance of molybdenum phosphide catalysts for dibenzothiophene hydrodesulfurization

Two series of alumina-supported molybdenum phosphide (MoP) catalysts with low and high metal loadings were prepared by temperature-programmed reduction of the oxidic catalyst precursors in hydrogen to different temperatures (823, 923, 1023 and 1123 K, respectively). Effects of reduction temperature and metal loading on the surface distribution and the type of species formed were studied by TPR, S_BET, XRD, HRTEM, ³¹P NMR, ²⁷Al NMR and in the reaction of dibenzothiophene (DBT) hydrodesulfurization (HDS) performed in a flow reactor at 553 K and total hydrogen pressure of 3.4 MPa. HRTEM and ³¹P NMR confirmed formation of MoP phase on all catalysts. The 9.9 wt% Mo catalyst activated at lowest reduction temperature (823 K) was found to be most active among the catalysts studied. The presence of a low amount of Mo⁰ species on the surface of this catalyst does not appear to be a drawback for the catalytic activity. The increase in both metal loading (from 9.9 to 15 wt% Mo and from 3.2 to 4.8 wt% P) and reduction temperature (from 823 to 1123 K) was found to be detrimental for HDS activity due to sintering of active phase, and also to decrease in specific area and formation of phosphate species.     

还原终温对磷化物催化剂加氢脱硫反应性能的影响

以全硅MCM-41为载体,制备负载Ni2P和Mop型催化剂,考察了还原终温对催化剂制备和加氢脱硫反应性能的影响.对于Ni2P/MCM-41,NiO负载质量分数为12%,通过XRD和加氢脱硫反应评价得出最佳还原终温为500℃;对于MoP/MCM-41,MoO3负载质量分数为40%,通过XRD和加氢脱硫反应评价得出最佳还原...     

Nickel and cobalt promoted tungsten and molybdenum sulfide mesoporous catalysts for hydrodesulfurization

High-performance hydrodesulfurization (HDS) catalysts were prepared by incipient wetness impregnation of Ni-Mo(W) and Co-Mo(W) species over siliceous MCM-41 doped with zirconium. Catalysts with W and Mo loadings of 20 and 11 wt%, respectively, and with a Ni or Co loading of 5 wt%, were prepared. As a reference, a nickel-tungsten catalyst supported on a commercial γ-Al₂O₃ with a 5 and 20 wt% metal loadings, respectively has also been prepared. HDS reaction of dibenzothiophene (DBT) under 3.0 MPa of total pressure and with hourly space velocity (WHSV) of 28 h⁻¹ was used to evaluate the activity of these sulfided catalysts. All the catalysts displayed a very good performance in the temperature range of 300-340 °C, with conversions between 49.0% and 92.6%. The Ni promoted catalysts displayed better performances than those of Co promoted catalysts in the HDS of DBT. On the other hand they show different selectivity to hydrogenation, thus, in Ni promoted catalysts, the hydrogenation (HYD) reaction contributes more to the conversion of DBT than Co promoted catalysts where the direct desulfurization (DDS) reaction is more important. The performance of this set of catalysts is similar to that observed with a Ni5W20-Al₂O₃ catalyst in the same range of temperature (300-340 °C). However, the selectivity to the HYD product, CHB, observed with nickel promoted catalysts (Ni5-Mo11 and Ni5-W20) is higher than that found for Ni5W20-Al₂O₃ catalyst probably due to a higher superficial area of the MCM-support and to the presence on the surface of zirconium species, which leading to a better dispersion and lower stacking of the active phases.     

Comparison of molybdenum carbide and tungsten carbide for the hydrodesulfurization of dibenzothiophene

The molybdenum and tungsten carbides (Mo₂C and W₂C) were synthesized, characterized and tested in hydrodesulfurization (HDS) of dibenzothiophene (DBT). The phase purity of these catalysts was established by X-ray diffraction (XRD), and the surface properties were determined by N₂ BET specific surface area (Sg) measurements, CO chemisorption and high-resolution transmission electron microscopy (HRTEM). The activities of catalysts were determined during the HDS of DBT at a temperature of 613 K and under a 6 MPa total pressure. Both molybdenum and tungsten carbides were active in HDS of DBT. The reactivity studies showed that molybdenum carbide was more active than tungsten carbide related to weight. However, W₂C was shown to possess stronger hydrogenating properties.     

Mo/REHY催化剂的加氢脱硫性能

将钼酸按溶液与REHY等体积浸渍和焙烧,制备了Mo/REHY催化剂,采用XRD和NH3-TPD对其进行表征.以质量分数0.6%的二苯并噻吩/正癸烷溶液为模型反应物评价其加氢脱硫性能.结果表明,不同焙烧温度制备的Mo/REHY催化剂,归属于REHY的晶相峰保持完好,金属活性组分Mo进入REHY体相超笼,引起REHY分子筛...     

不同担载量介微孔复合分子筛加氢脱硫催化剂性能研究

以ZSM-5/KIT-1(ZK-1)介微孔复合分子筛为载体,采用浸渍法分别制备了金属担载量为8%Mo3%Co,16%Mo6%Co,20%Mo7%Co和24%Mo8%Co的加氢脱硫催化剂。利用X射线衍射(XRD)、N2吸附脱附分析、紫外可见漫反射(UV-vis)表征手段分析其结构;以3%(wt)的CS2/环己烷溶液为硫化液,500×10-6的二苯并噻吩/十氢萘溶液为原料液,在小型固定床反应器中评价催化剂的加氢脱硫反应活性。实验结果表明ZSM-5/KIT-1介微孔复合分子筛作为加氢脱硫催化剂载体具有优异的反应性能。当催化剂的担载量达到20%Mo7%Co时,表现出最佳的加氢脱硫反应活性,脱硫率为93%,高于相同反应条件下的商业用催化剂。     

制备条件对Ni2P/TiO2-Al2O3催化剂加氢脱硫性能的影响

采用溶胶-凝胶法制备了TiO₂-Al₂O₃复合载体, 以柠檬酸为络合剂, 浸渍法制备了负载型Ni₂P/TiO₂-Al₂O₃催化剂前体, 程序升温H₂还原法制备了Ni₂P/TiO₂-Al₂O₃催化剂, 并用 X 射线衍射(XRD)、N₂吸附比表面积(BET)测定技术对催化剂的结构和性质进行了表征, 考察了浸渍方法、Ni/P摩尔比、Ni₂P负载量对其进行的二苯并噻吩(DBT)加氢脱硫(HDS)性能的影响。结果表明, 当Ni/P比低于1:1时, 能得到单一的Ni₂P物相;当Ni/P比为2:1时, 开始出现Ni₃P物相。采用Ni/P比为1:1、Ni₂P负载量为30%、采用共浸渍方法制备的Ni₂P/TiO₂-Al₂O₃催化剂具有最好的活性, 在360℃、3.0MPa、氢油比500 (体积比)、液时体积空速2.0h^-1的条件下反应4h时, 二苯并噻吩转化率为99.5%。     

Study of the Individual Reactions of Hydrodesulphurization of Dibenzothiophene and Hydrogenation of 2-Methylnaphthalene on ZnNiMo/γ-Alumina Catalysts

A series of ZnNiMo/γ-alumina catalysts with variable Zn/(Ni + Zn) ratio were synthesized. These catalysts were characterized by chemical analysis, temperature programmed reduction (TPR) and BET surface area. After that, these catalysts were tested in the individual reactions of hydrodesulphurization (HDS) of dibenzothiophene (DBT) and hydrogenation (HYD) of 2-methylnaphthalene (2MN). The results showed an increment of the catalytic activity, for both reactions, when the catalysts were doubly promoted with Ni and Zn in comparison to those mono-promoted catalysts.