Pd nanoparticles immobilized on MIL-53(Al) as highly e ective bifunctional catalysts for oxidation of liquid methanol to methyl formate

A series of Pd/MIL-53(Al) heterogeneous bifunctional catalysts with di erent Pd contents were prepared by an impregnation method. The prepared metal–organic frameworks MIL-53(Al) and catalysts were characterized by XRD, SEM, HRTEM,FT-IR and N2 adsorption/desorption techniques. The results showed that MIL-53(Al) was synthesized successfully, and the structure was unchanged during and after the preparation of the catalysts. The Pd nanoparticles(NPs) with an average particle size of 4.6 nm were uniformly dispersed on the MIL-53(Al). The catalyst exhibited good catalytic activity in the selective oxidation of liquid methanol to methyl formate. Under the conditions of 150 °C, 2 MPa O_2 and solvent-free for5 h, the conversion of methanol could reach 60.3%, and the selectivity of methyl formate was up to 62.2%. In addition, the Pd/MIL-53(Al) bifunctional catalyst exhibited excellent stability and maintained high catalytic activity after five cycles.     

Pd nanoparticles immobilized on MIL-53(Al) as highly effective bifunctional catalysts for oxidation of liquid methanol to methyl formate

A series of Pd/MIL-53(Al) heterogeneous bifunctional catalysts with different Pd contents were prepared by an impregnation method. The prepared metal–organic frameworks MIL-53(Al) and catalysts were characterized by XRD, SEM, HRTEM, FT-IR and N₂ adsorption/desorption techniques. The results showed that MIL-53(Al) was synthesized successfully, and the structure was unchanged during and after the preparation of the catalysts. The Pd nanoparticles (NPs) with an average particle size of 4.6 nm were uniformly dispersed on the MIL-53(Al). The catalyst exhibited good catalytic activity in the selective oxidation of liquid methanol to methyl formate. Under the conditions of 150 ℃, 2 MPa O₂ and solvent-free for 5 h, the conversion of methanol could reach 60.3%, and the selectivity of methyl formate was up to 62.2%. In addition, the Pd/MIL-53(Al) bifunctional catalyst exhibited excellent stability and maintained high catalytic activity after five cycles.     

二氧化硅负载Cr(acac)3/PNP催化剂的制备及其催化乙烯四聚反应性能研究

Chromium acetylacetonate and bis(diphenylphosphino)isopropylamine were coordinated in situ and supported on methylaluminoxane-modified silica. The catalyst structure and effects of reaction temperature, reaction pressure and Al/Cr molar ratio on ethylene tetramerization were investigated in detail. Chromium was uniformly and firmly immobilized on the support and could not be leached off by methylaluminoxane. The supported catalyst, upon being activated with methylaluminoxane, exhibited catalytic activity of 1.70×107 g/(mol Cr·h) for ethylene tetramerization to form 1-octene at a reaction temperatures of 80 ℃, a pressure of 2.0 MPa and an Al/Cr molar ratio of 300. The supported catalyst presented a good tolerance to high temperature.     

钨酸锆催化剂的成型以及黏结剂在异构化中的作用

The present work reports the new results of pseudo-boehmite addition as binder in the synthesis of the shaped Pt/WO3-ZrO2-Al2O3 (denoted as PtWZA) catalysts. The results showed that the shaping with binder can noticeably influence the structure, acidity of catalyst and then improved the catalytic performance in n-heptane isomerization, except for providing the mechanical strength of the catalyst. The suitable binder content could improve the isomerization activity and/or selectivity by changing the acidity of PtWZA. The influence of binder content depended on WO3 content in the catalyst. The PtWZA catalysts containing 5-15wt% binder (dry basis content of binder) possessed favorable isomerization performance, depending on the contents of WO3. The suitable catalyst contained Pt20WZ5A and Pt30WZ15A, which could give approximately 80-90% conversion and 90% selectivity. These new findings enriched the knowledge of the binder in the catalyst shaping process that will be useful in the production of industrial catalysts.     

正庚烷催化裂解生产低碳烯烃的影响因素探索

The influence of zeolite structure and process parameters (including reaction temperature and catalyst/oil ratio) on rules for formation of ethylene and propylene in the course of catalytic pyrolysis of n-heptane was studied in a small- scale fixed fluid catalytic cracking unit. Test results have revealed that compared to the USY zeolite and Beta zeolite, the catalytic pyrolysis of n-heptane in the presence of the ZRP zeolite catalyst can result in higher yield and selectivity of ethyl- ene and propylene, while a higher reaction temperature and a higher catalyst/oil ratio can promote the formation of ethylene and propylene during catalytic pyrolysis of n-heptane. The ethylene formation reaction is more sensitive to the changes in reaction temperature, whereas the changes in catalyst/oil ratio are more influential to the propylene formation reaction. This paper has made a preliminary exploration into the different reaction pathways for formation of ethylene and propylene on zeolites with different structures.     

Highly Active and Stable Ni_2P/SiO_2 Catalyst for Hydrogenation of C_9 Petroleum Resin

Catalytic hydrogenation is an appropriate method for the improvement of C_9 petroleum resin(C_9PR) quality. In this study, the Ni_2P/SiO_2(containing 10% of Ni) catalyst prepared by the temperature-programmed reduction(TPR) method was used for hydrogenation of C9 petroleum resins. The effect of reaction conditions on catalytic performance was studied, and the results showed that the optimum reaction temperature, pressure and liquid hourly space velocity(LHSV) was 250 ℃, 6.0 MPa, and 1.0 h-1, respectively. The bromine numbers of hydrogenated products were maintained at low values(~250 mg Br/100g) within 300h, showing the high activity and stability of Ni_2P/SiO_2 catalyst. The fresh and spent catalysts were characterized by X-ray diffraction(XRD), BET surface area(BET) analysis, scanning electron microscopy(SEM), transmission electron microscopy(TEM), Fourier transform infrared(FTIR) pyridine adsorption, and X-ray photoelectron spectroscopy(XPS). Compared with the traditional sulfurated-Ni W catalysts, Ni_2P possessed globe-like structure instead of layered structure like the active phase of Ni WS, thereof exposing more active sites, which were responsible for the high activity of Ni_2P/SiO_2 catalyst. The stability of Ni_2P/SiO_2 catalyst was probably attributed to its high sulfur tolerance, antisintering, anti-coking and carbon-resistance ability. These properties might be further ascribed to the special Ni-P-S surface phase, high thermal stability of Ni_2P nanoparticles and weak surface acidity for the Ni_2P/SiO_2 catalyst.     

Ni2P-MoS2/γ-Al2O3催化剂的加氢路径脱硫性能

A series of highly active Ni2P-MoS2/γ-Al2O3 catalysts were prepared and characterized, the catalytic performanceof which was evaluated through hydrodesulfurization of dibenzothiophene. The result indicated that when the amount ofNi2P was 4%, the catalyst showed a relatively high activity to provide a reliable reference for the hydrodesulfurization pathwayin comparison with the conventional NiMo and NiMoP catalysts. The physicochemical properties of the catalysts werecorrelated with their catalytic activity and selectivity on hydrodesulfurization. The stacking number of active MoS2 phaseswas important for influencing the hydrogenation activity.     

Influence of Alumina Content on Catalytic Performance of PtSn/Al2O3/SBA-15 Catalysts for Propane Dehydrogenation

The alumina-modified SBA-15 (Al2O3/SBA-15) zeolite was prepared in a non-aqueous system by using toluene as the solvent, and was used to support the PtSn-based catalyst for propane dehydrogenation. The BET surface area measurements, hydrogen chemisorption, FT-IR spectroscopy, NH3-TPD, XPS and TPO techniques were used to characterize the catalysts. Test results showed that the addition of alumina not only could modify the acid function of the support but also the structure of the metallic phase, thus affecting their catalytic properties. Among these catalysts studied, the PtSn/Al2O3 (5%)/SBA-15 catalyst exhibited a best catalytic performance in terms of propane conversion and selectivity to propene. The high catalytic performance might be attributed to the relatively good Pt metal dispersion and/or the strong interaction between Pt and Sn species.     

SiW/Hβ催化剂用于挂式四氢双环戊二烯的制备

Exo-tetrahydrodicyclopentadiene (exo-TCD) is an important high-energy fuel.Silicotungstic acid (SiW) immobilized on H-type β zeolite (Hβ) at room temperature were used to prepare the Hβ zeolite catalysts with different SiW contents.Catalytic performances of the catalysts were investigated during the preparation of exo-TCD via isomerization of endo-tetrahydrodicyclopentadiene (endo-TCD).The properties of catalysts were characterized by XRD,temperature pro-grammed desorption of ammonia (NH 3-TPD),FT-IR,and N 2-adsorption techniques.SiW was highly dispersed on the surface of Hβ zeolite,and the 10% SiW/Hβ zeolite catalyst had the highest amount of weak acidity among all SiW/Hβ zeolite catalysts.The influence of different factors on isomerization reaction was investigated.At a reaction temperature of 240 ℃,a n(cyclohexane) /n(endo-TCD) ratio of 10,a m(catalyst) /m(endo-TCD) ratio of 0.3,an initial pressure of 1.0 MPa,and a reaction time of 1.5 h in the presence of 10% SiW/Hβ catalyst calcined at 400 ℃,the conversion of endo-TCD reached up to 92.0%,with the yield of exo-TCD equating to 51.0%.     

DEVELOPMENT OF SUPERIOR RESID DEMETALLIZATION CATALYST AND ITS APPLICATION

The effects of the pore structure of the bimodal catalyst on the residue hydrodemetallization were studied. The simulation of the intra-particle reaction model suggested that an increase in the diffusivity of the macro pore increase the demetallization. The activity tests of several catalyst samples with different pore structure supported the predicted resuits. The new birnodal dematallization catalyst with high demetallization activity as well as large metal uptake capacity was developed, by improving the pore structure and the hydrogenation activity. The pilot runs demonstrated that the new catalyst possesses longer catalytic life as well as higher demetallization activity in the residue desulfurization process.     

MIL-101（Cr）在H2O2氧化环己烷反应中的催化性能

采用水热合成法制备了MIL-101(Cr)催化剂,考察了反应条件对其在H2O2氧化环己烷反应中催化性能的影响。利用XRD、FT-IR和UV-Vis等手段对MIL-101(Cr)反应前后结构的变化进行了表征。结果表明,MIL-101(Cr)在所选择的反应体系中存在Cr析出现象,其结构在以H2O2为氧化剂的反应体系中不稳定,经反应后形成了无定型物质,但催化活性不仅远高于新鲜MIL-101(Cr),而且还在重复利用中表现出良好的稳定性。     

Pt/PTA-MIL-101(Cr)的合成及其正庚烷异构催化性能

使用磷钨酸(PTA)对金属有机骨架材料MIL-101(Cr)进行改性,制备了0.4%Pt/PTA-MIL-101(Cr)催化剂,并首次应用于正庚烷异构化反应。通过对样品进行一系列表征,得出以下结论：所合成的样品为介孔-微孔复合材料,具有正八面体结构,孔道结构规整有序,比表面积高;掺杂PTA后,未破坏MIL-101(Cr)的骨架结构和热稳定性;PTA在催化剂中仍可保持其Keggin结构,可为催化反应提供良好的酸性环境;Pt在MIL-101(Cr)中的分散度较高。通过正庚烷异构化反应对催化剂性能进行评价,得出在PTA掺杂量(w)为30%、反应温度为260 ℃时,催化剂的酸性位点与金属位点的匹配度最适宜催化庚烷异构化反应,此时催化剂上正庚烷转化率与异庚烷选择性分别可达69.1%和93.7%。     

Keggin型磁性多酸负载型催化剂的制备及其燃油氧化脱硫性能

采用简单的一锅法合成了一类氨基修饰的磁性MIL-101(Cr)载体固载下的Keggin型多酸催化剂,即Fe₃O₄@MIL-101-PMoW(简称FeCuP),通过傅里叶变换红外光谱(FT-IR)、X射线衍射(XRD)、N₂吸附-脱附等温(BET)以及振动样品磁强计(VSM)等手段对其组成、形貌等进行表征。采用该催化剂催化以空气中的氧气为氧化剂、以二苯并噻吩(DBT)为硫源的正十二烷模拟油样。结果表明,多酸具有较好的脱硫效果,随着多酸活性组分的引入,在最优反应条件下,FeCuP催化氧化模拟燃油中DBT的脱硫率可在75 min内达到100%。此外,磁性材料的修饰可大大增加FeCuP催化剂的回收率,采用简单的外加磁场即可实现催化剂的回收与再利用,重复使用10次以上仍保持95%以上的脱硫率。FeCuP催化剂在脱硫率以及重复使用次数上的明显优化满足了当今脱硫工业化的使用要求,具有较大的利用及推广价值。     

Analysis of Syneresis of HPAm/Cr(II) and HPAm/Cr(III) Acetate Gels Through 1H Nuclear Magnetic Resonance,Bottle Testing,and UV-vis Spectroscopy

Abstract

Polymer solutions with 7500 mg/L of partly hydrolyzed polyacrylamide were crosslinked with Cr(III) acetate 50% active, Cr(III) acetate hydroxide, and Cr(II) acetate respectively. A syneresis-inducing polymer to crosslinker weight ratio of 5/1 was employed. An empirical correlation was found between ¹H NMR data and gel syneresis. Chromium speciation indicated that at the experimental conditions used aging the gels did not favor the oxidation of Cr(II) or Cr(III) to Cr(VI). The polymer solution crosslinked with Cr(III) acetate 50% active behaved similar to that cross-linked with Cr(III) acetate hydroxide.     

Cr沸石在环己烷氧化反应中的催化性能

以环己烷氧化反应为探针,系统地比较了采用离子交换法、“ship-in-bottle”法和水热法制备的C r沸石的催化性能和稳定性。通过X射线衍射、氮吸附、傅里叶变换红外光谱、漫反射紫外-可见光谱和差热分析方法对催化剂进行了表征。分析结果表明,不同方法制备的C r沸石催化剂的性质和状态不同。实验结果表明,水热法制备的C rY催化剂的催化活性最高,但C r的浸出最严重。选择不同Schiff碱配体N,N′-双(水杨醛)-丙二胺(L1)和N,N′-双(水杨醛)-环己二胺(L2)、采用“ship-in-bottle”法制备的C rL1/Y和C rL2/Y催化剂的性能均优于离子交换法制备的C r/Y催化剂,其中C rL2/Y催化剂的性能尤为突出,配体对催化剂的性能也有一定影响。     

1H NMR,Rheology, and Bottle Testing of HPAm/Cr(III) Acetate Micro Gels

Abstract

Solutions formulated at 40°C with partly hydrolyzed polyacrylamide (HPAm) and Cr(III) acetate 50% active were monitored for 240 hr using ¹H nuclear magnetic resonance (¹H NMR). The HPAm concentration was kept constant at 2,500 mg/L (which is slightly below the critical polymer concentration) and the HPAm to Cr(III) acetate weight ratio ranged from 5:1 to 60:1. Changes in the ¹H NMR transverse relaxation (T ₂) of the solutions were dominated by the chemistry of Cr(III) acetate. ¹H NMR detected changes immediately after HPAm started reacting with Cr(III) acetate. These changes were undetectable by rheology or bottle testing of the studied solutions.     

逆水煤气变换耦合乙烷脱氢制乙烯反应的Cr/活性炭催化剂

在常压固定床微分反应器上,考察了活性炭及其负载的金属氧化物催化剂对逆水煤气变换耦合乙烷脱氢制乙烯反应的催化活性。实验结果表明,以活性炭为载体的Cr氧化物(Cr/C)催化剂具有较好的催化性能,采用5%(w)Cr/C催化剂,在700℃、原料气n(CO2)∶n(C2H6)=7∶1的条件下,乙烷转化率为56.2%,乙烯选择性和收率分别为75.0%和42.2%。反应中CO2的主要作用是通过与乙烷脱氢产物H2反应来促进乙烯的生成,提高反应活性;同时与积碳反应生成CO,消除表面积碳,提高催化剂的稳定性。通过对催化剂进行表征,研究了催化剂中活性组分的氧化还原性质和表面酸性对其催化性能的影响。XPS表征结果显示,催化剂表面存在Cr6+和Cr3+,高价态Cr有利于乙烷转化;微量吸附量热分析结果显示,催化剂表面的酸中心数量、强度及其分布与反应活性相关。     

Synthesis and optimization of a new MIL-100 adsorbent for removing basic N-compounds from liquid fuels

Abstract

In this work, the effects of synthesis conditions of MIL-100(Cr) as an adsorbent for quinoline (QUI) were evaluated by performing Taguchi-designed experimental tests. According to the analysis of variance (ANOVA), synthesis temperature was the most influential factor in maximizing QUI adsorption capacity of MIL-100(Cr). Moreover, the optimum temperature, time and reactants molar ratio were found to be 393?K, 15?h and 0.67, respectively. The QUI adsorption capacity of optimized MIL-100(Cr) was 15.70?mg_N.g^?1_ads. This adsorbent was characterized by specific surface area (BET), X-ray powder diffraction patterns (XRD) and Fourier transform infrared spectroscopy (FTIR) tests.     

模板剂和助剂对Pt/MOR催化剂临氢异构催化性能的影响

在分别以十二烷基苯磺酸钠（SDBS）、复合聚乙二醇20000（PEG20000）和十六烷基三甲基溴化铵（CTAB）为模板剂合成的梯级孔MOR分子筛上负载Pt制备了Pt/MOR催化剂,并用分步浸渍法在所得催化剂上分别引入第二金属组分Ni和Cr;采用XRD、N2吸附-脱附、CO脉冲化学吸附、H2-TPR、NH3-TPD和Py-IR等技术对所得样品进行了表征。结果表明：复合模板剂的添加有效地引入了介孔,所得MOR的介孔表面积和介孔体积分别从36.4%和52.9%增加到54.2%和76.5%,平均孔径从2.1 nm增加到3.9 nm;Ni或Cr的引入明显增加了催化剂的总酸量和L酸量,显著改善了金属Pt的分散度,且Cr的作用效果优于Ni。在引入1% Cr的Pt/MOR催化剂上,正辛烷临氢异构的转化率可达59.3%,其异构产物选择性可达94.9%。     

Fe_2O_3-V_2O_5掺杂,Cr_2O_3催化间甲酚甲基化制2,3,6三甲基苯酚

为得到高效低温催化剂,在Fe2O3-V2O5复合氧化物催化剂中添加不同金属氧化物MaOb(MaOb=CeO2,CaO,ZnO,ZrO2,Cr2O3)对其进行改性,制得Fe2O3-V2O5-MaOb催化剂,并将其用于间甲酚甲基化制备2,3,6-三甲基苯酚的反应。实验结果表明,按n(Fe):n(V):n(Cr)=100.0:1.0:0.5的比例添加Cr2O3可有效改善Fe2O3-V2O5催化剂的活性,优化的Fe2O3-V2O5-Cr2O3催化剂制备条件为:焙烧温度450℃、焙烧时间4 h、沉淀剂为25%(w)氨水。采用优化条件下制备的Fe2O3-V2O5-Cr2O3催化剂进行间甲酚甲基化反应,适宜的反应条件为:反应温度330℃、进料液态空速0.53 h-1。在优化反应条件下,间甲酚转化率为99.2%,2,3,6-三甲基苯酚选择性为94.6%。