3-甲酰基-7β-苯乙酰胺基-3-头孢-4-羧酸二苯甲基的催化脱羰基反应

用常见膦配体与 ［IrCl(cod)］₂(cod为1,5-环辛四烯)、RuCl₂(cod)或RhCl₃形成的复合催化剂及以SBA-15、 MCM-41和MCM-48为载体所形成的负载型复合催化剂,对3-甲酰基-7β-苯乙酰胺-3-头孢-4-羧酸二苯甲基酯进行了催化脱羰基反应研究。结果发现,催化剂用量为底物物质的量的5%时,［IrCl(cod)］₂/SBA-15/亚磷酸三乙酯负载型复合催化剂脱羰基反应的产率最高,高效液相色谱产率为32%,柱色谱分离产率为23%,与文献报道的以化学计量RhCl(PPh₃)₃对该化合物进行脱羰基反应的产率相当,不但大大减少了贵金属的使用量,而且催化剂可以重复使用。     

Sn修饰SBA-15、MCM-41催化剂的制备及顺酐酯化性能

以SBA-15和MCM-41分子筛为载体,负载无水四氯化锡,制备了SnCl4-SBA-15和SnCl4-MCM-41催化剂,考察了不同锡与硅物质的量比对催化顺酐与正丁醇酯化反应的影响。结果表明,SnCl4-SBA-15表现出比SnCl4-MCM-41更高的催化性能,顺酐转化率为99.8%,副产物较少,马来酸二丁酯的产率最高可达91.3%。采用X射线衍射、N₂物理吸附、傅立叶红外光谱和紫外-可见漫反射技术对催化剂进行表征,结果显示, SnCl₄-SBA-15具有较高的比表面积,较大的孔容和孔径,更有利于催化反应的进行。     

酞菁铜/介孔分子筛复合催化剂催化氧化巯基乙醇的研究

采用浸渍法将α-八-(异戊氧基)酞菁铜分别负载在SBA-15和MCM-41介孔分子筛上,制备了CuPc/SBA-15和CuPc/MCM-412种复合催化剂。通过紫外-可见吸收光谱、红外光谱和N2吸附方法对催化剂的结构和组成进行了表征。测试了2种催化剂对巯基乙醇的催化氧化性能,并考察了温度对催化氧化活性的影响。实验结果表明,在pH=11时,CuPc/SBA-15催化氧化巯基乙醇的转化率高于CuPc/MCM-41;随着温度的升高,CuPc/SBA-15对巯基乙醇的转化率逐渐增大,并计算了CuPc/SBA-15催化反应在25℃时的活化能Ea为30.50kJ/mol。     

溶剂热浸渍法制备高稳定性Zn(OAc)2/SiO2催化剂及其催化合成苯氨基甲酸甲酯

Zn(OAc)₂对由碳酸二甲酯（DMC）和苯胺合成苯氨基甲酸甲酯（MPC）的反应具有优异的催化性能,但存在易失活、不能重复使用的缺点。为此,以DMC为溶剂,利用溶剂热浸渍法制备Zn(OAc)₂/SiO₂催化剂,并对其催化性能进行了研究。利用XRD、FTIR和TG-DTA等方法对其进行了表征,结果表明,Zn(OAc)₂/SiO₂催化剂表面存在Zn(OAc)₂和ZnO,且其在SiO₂表面分散较好;优化了Zn(OAc)₂/SiO₂催化剂的反应条件,当反应温度为190℃、反应时间为5h、苯胺与DMC的摩尔比为1∶20、催化剂与苯胺质量比为0.2时,苯胺的转化率为97.2%,MPC的选择性为89.4%。和等体积浸渍法制备的催化剂相比,溶剂热浸渍法制备的Zn(OAc)₂/SiO₂催化剂具有较好的稳定性,重复使用7次,苯胺的转化率下降至79.1%,MPC的选择性下降至79.2%。Zn(OAc)₂/SiO₂活性下降的原因是由于ZnO的生成,并对其进行了再生,再生后的催化剂活性与新鲜催化剂接近。     

Co掺杂对Ce/MCM-41和Ce/SBA-15催化剂催化氧化甲苯性能的影响

以分子筛为载体,采用等体积浸渍法制备Ce/SBA-15、Ce/MCM-41、Ce Co/SBA-15和Ce Co/MCM-41催化剂。用N2吸附-脱附、X射线衍射、扫描电子显微镜、H2程序升温还原、X射线光电子能谱和傅立叶变换红外光谱等对载体和催化剂进行表征,并考察催化剂催化氧化甲苯的活性。结果表明,与载体相比,随着Ce和Co的浸渍,催化剂的比表面积和孔容下降,但仍然保持了载体的有序介孔结构。引入的Ce和Co没有进入分子筛骨架,而是以立方相固溶体形式存在于分子筛表面和孔道中。催化剂催化氧化甲苯活性顺序依次为:Ce Co/SBA-15>Ce Co/MCM-41>Ce/MCM-41>Ce/SBA-15。共浸渍Ce和Co的催化剂活性明显优于只浸渍Ce的催化剂,活性与其还原性能直接相关,Ce Co/SBA-15催化剂具有最低的还原温度和最好的供氧能力,从而表现出最优的催化性能。     

SBA-15锚定的钌杂多酸催化剂的合成及其催化正十六烷氧化

利用(3-氨丙基)三乙氧基硅烷(apts)将钌金属杂多酸[X₂W₂₀O₇₀(RuY)₂]^10-(其中,X为锑或铋,Y为苯或对异丙基苯甲烷)固定在介孔的SBA-15上可得到一系列性能优良的SBA-15锚定的钌杂多酸催化剂。采用XRD、N₂吸附-脱附实验和FT-IR红外光谱对此类催化剂进行表征,并检测其对正十六烷氧化的催化性能。结果表明,以空气为氧化剂,在无任何溶剂的条件下,该锚定的钌杂多酸催化剂遵循传统的自由基自氧化机理,将正十六烷烃氧化成各种醇类和酮类,显示出优良的催化性能。因此,这类多相催化剂对环境友好的烷烃氧化反应具有较高的应用价值。     

类水滑石的制备及其焙烧产物催化苯制苯酚

采用共沉淀法制备了类水滑石CuNiAl,450 ℃焙烧后得到复合氧化物催化剂,利用XRD和FT-IR对其结构进行表征。研究了该催化剂体系对苯直接氧化制苯酚反应的催化性能,并考察了反应温度、反应时间、催化剂用量、溶剂用量和n(C₆H₆)∶n(H₂O₂)对收率的影响。结果表明,类水滑石CuNiAl经焙烧后,催化苯直接氧化制苯酚反应的转化率提高,适宜的反应条件为：反应温度65 ℃,反应时间6 h,催化剂用量10 mg,溶剂用量15 mL,n(C₆H₆)∶n(H₂O₂)=3∶1,产物中没有发现副产物,苯转化率达6.5%。     

配体功能化负载型磷钼酸催化剂的制备及其氧化脱硫性能研究

以有机配体功能化的SBA-15为载体,将Co取代的磷钼酸（Co-POM）负载于功能化SBA-15载体上制备负载型催化剂。利用XRD、FT-IR、BET、TEM、TG等对催化剂结构进行表征。结果表明,—octyl、—NH₂基团成功嫁接到载体SBA-15上;催化剂的整体结构没有发生明显改变,催化剂活性组分均匀地分散在介孔SBA-15的表面和孔道中。以二苯并噻吩（DBT）为底物进行氧化脱硫反应,考察催化剂结构对催化活性的影响。结果表明,—octyl和—NH₂基团双功能化的催化剂（CO-POM-octyl-NH₂-SBA-15）脱硫效果最好,在反应温度为60℃、负载量为30%、反应时间为8 h、剂油体积比为1∶1的最佳反应条件下,催化剂对DBT脱除率达到94.95%。循环使用5次后,催化性能没有明显降低,具有良好的循环稳定性。     

CO2加氢制甲醇Cu-Zn-Al水滑石催化剂的改性研究

CO₂加氢制甲醇既能有效缓解温室效应带来的全球气温升高问题,也能促进CO₂的资源化利用,成为研究热点之一。对Cu-Zn-Al水滑石(CZA-LDH)开展改性研究,以Cu(NO₃)₂·3H₂O、Zn(NO₃)₂·6H₂O和Al(NO₃)₃·9H₂O为原料,以NaOH和NaCO₃为沉淀剂,采用共沉淀法制备CZA-LDH,并在制备过程中引入聚乙二醇(PEG)、聚乙烯吡咯烷酮(PVP)和三乙醇胺(TEA),焙烧后得到4组催化剂。XRD、FT-IR、N₂吸附-脱附、SEM表征结果及催化性能测试数据表明,引入TEA的CZA-LDH焙烧后得到的复合金属氧化物催化剂(CZA-LDO-TEA)表现出最优的性能。这是因为TEA 能够破坏表面晶体结构,促进催化剂中CuO组分的还原,提高了 CO₂的化学吸附能力,从而提高了催化剂的CO₂转化率。     

GaN-ZnO/MCM-41的制备及其催化CO2氧化丙烷脱氢制丙烯反应

二氧化碳氧化丙烷脱氢制丙烯(CO₂-OPDH)工艺是丙烯生产路线中较为理想的途径,而高性能催化剂的研制是该工艺取得突破的关键。以介孔分子筛MCM-41为载体,GaN-ZnO固溶体为活性组分,通过固相氮化法构筑具有双功能活性中心的GaN-ZnO/MCM-41催化剂,并对其催化CO₂-OPDH反应性能进行了研究。结合X射线衍射光谱(XRD)、氮气吸脱附测试、场发射扫描电镜-能谱(SEM-EDX)、透射电子显微镜(TEM)、热重-质谱联用(TG-MS)以及拉曼光谱(Raman),对催化剂的物理化学性质进行了表征分析。研究表明,固相氮化法能够制备出固溶体催化剂,且该催化剂表现出有效的催化丙烷脱氢性能,优于相同反应条件下负载的单组分氮化镓或氧化锌催化剂。在600℃,CO₂气氛下,Ga0.5-Zn0.5/MCM-41-800的丙烷转化率为21%,丙烯选择性高达92%。固溶体结构有利于活性组分的分散,能够产生更多的活性位点,而焙烧温度影响固溶体的组成结构,进而影响其催化活性。此外,CO₂不仅能提高催化剂的活性,而...     

Effect of Zr-SBA-15 support on catalytic functionalities of Mo, CoMo, NiMo hydrotreating catalysts

SBA-15 and ZrO₂ (10–50 wt.%) containing SBA-15 mesoporous materials were prepared by direct and post-synthesis methods. Characterization using low angle XRD, pore size distribution, CO₂ chemisorption indicate that hexagonal mesoporous structure is retained even after ZrO₂ addition (25 wt.%). Mo, CoMo and NiMo catalysts prepared using these supports were examined by XRD, oxygen chemisorption, temperature programmed reduction (TPR). The catalysts were tested for hydrodesulfurization (HDS) of thiophene and hydrogenation (HYD) of cyclohexene. HDS of thiophene for 8%Mo, 3%Co8%Mo, and 3%Ni8%Mo increases with increasing ZrO₂ loading in SBA-15 up to 25 wt.%. Oxygen chemisorption and TPR hydrogen consumption indicated that the molybdenum dispersion and anion vacancies, and catalytic activities are significantly influenced by ZrO₂ content in Zr-SBA-15. A comparison indicated that TiO₂-SBA-15, ZrO₂-SBA-15 supported CoMo catalysts show higher activities for hydrodesulfurization.     

水基纳米TiO_2路径制备有序介孔TiO_2-SiO_2及其可见光催化性能

在多巴胺修饰的水基TiO_2纳米微粒(TiO_2NPs)悬浮液中,以正硅酸乙酯为硅源,十六烷基三甲基溴化铵为模板剂,分别采用碱性水热方法或酸性溶胶-凝胶方法,制备了有序介孔TiO_2-SiO_2(TiO_2NPs/MCM-41或TiO_2NPs/SBA-3)。采用XRD、TEM、ICP和N2吸附-脱附实验对样品进行表征。结果表明,制备的介孔TiO_2-SiO_2在TiO_2高负载质量分数(23.98%TiO_2NPs/MCM-41、17.27%TiO_2NPs/SBA-3)时,仍能保持长程有序的介孔氧化硅结构。TiO_2NPs随机地嵌入在有序介孔氧化硅孔道所组成的网络结构中。在可见光下催化甲基橙降解反应中,反应时间120 min时,在P25上甲基橙相对浓度降为57%,在TiO_2NPs/MCM-41上降为33%,而在TiO_2NPs/SBA-3上降为5.7%。     

Mesoporous silicas containing carboxylic acid: Preparation,thermal degradation,and catalytic performance

The calcination and thermal degradation behaviors of surfactants in mesoporous silicas SBA-15 and MCM-41 were investigated by FT-IR, ¹³C CP/MAS NMR, TG/DTA, and GPC. It was found that carboxylic acid-containing products were generated as active components in the mesopores of SBA-15 and MCM-41 from the triblock copolymer (PEO)₂₀(PPO)₇₀(PEO)₂₀ and cetyltrimethylammonium bromide (CTAB), respectively; the latter materials were used as templates. The carboxylic acid-containing mesoporous silica obtained showed a catalytic activity for hydrolysis of sucrose. The acidity was evaluated by means of NaOH titration. The acidity sensitively depended on both the calcination temperature and the atmosphere; the maximum appeared at 150 °C in air for SBA-15 where the highest activity was observed. However, the product in MCM-41 showed a lower catalytic activity than that in SBA-15. The SBA-15 product was easily leached from the mesopores of SBA-15 into the solution, but the degree of leaching for MCM-41 was considerably smaller than that for SBA-15.     

Mesoporous molecular sieve MCM-41 supported Co–Mo catalyst for hydrodesulfurization of petroleum resids

In this work, we explored the potential of mesoporous zeolite-supported Co–Mo catalyst for hydrodesulfurization of petroleum resids, atmospheric and vacuum resids at 350–450°C under 6.9 MPa of H₂ pressure. A mesoporous molecular sieve of MCM-41 type was synthesized; which has SiO₂/Al₂O₃ ratio of about 41. MCM-41 supported Co–Mo catalyst was prepared by co-impregnation of Co(NO₃)₂·6H₂O and (NH₄)₆Mo₇O₂₄ followed by calcination and sulfidation. Commercial Al₂O₃ supported Co–Mo (criterion 344TL) and dispersed ammonium tetrathiomolybdate (ATTM) were also tested for comparison purposes. The results indicated that Co–Mo/MCM-41(H) is active for HDS, but is not as good as commercial Co–Mo/Al₂O₃ for desulfurization of petroleum resids. It appears that the pore size of the synthesized MCM-41 (28 Å) is not large enough to convert large-sized molecules such as asphaltene present in the petroleum resids. Removing asphaltene from the resid prior to HDS has been found to improve the catalytic activity of Co–Mo/MCM-41(H). The use of ATTM is not as effective as that of Co–Mo catalysts, but is better for conversions of >540°C fraction as compared to noncatalytic runs at 400–450°C.     

Synthesis of hexagonal and cubic mesoporous silica using power plant bottom ash

An alkali fusion method was adopted to extract silicate species from coal bottom ash in a power plant and the supernatant solution was used for the synthesis of MCM-41, SBA-15, and SBA-16 mesoporous silica materials. The minor impurities present in the bottom ash were not found to be detrimental to the successful formation of mesoporous silica phases. Additional silica from sodium metasilicate was introduced to improve the textural properties for SBA-15 and SBA-16. According to SEM analyses, particle morphology of the samples gradually approaches those prepared using pure chemical as the amount of external silica source increases. XRD analyses confirmed well-ordered mesostructures in all of these silica materials. N₂ adsorption–desorption isotherms of MCM-41 prepared using bottom ash showed a type IV isotherm with a region of steep increase due to capillary condensation, whilst SBA-15 and SBA-16 showed type IV isotherm with H1 and H2 hysteresis loops, respectively. ²⁷Al MAS NMR analysis of MCM-41 synthesized from the supernatant solution reveals that the extracted Al species from bottom ash were tetrahedrally incorporated in the framework. TEM clearly showed the uniform pore structure of the materials prepared using the industrial waste.     

Flash induction calcination: A powerful tool for total template removal and fine tuning of the hydrophobic/hydrophilic balance in SBA-15 type silica mesoporous materials

A new rapid calcination method has been used to completely remove the organic template from SBA-15 ordered mesoporous silica, and to preserve a high number of silanol in these materials. This calcination method provided by an induction furnace was found to considerably reduce the calcination time and therefore the energy consumption associated. Moreover, adjustment of both calcination temperature and duration allowed tuning the hydrophobic/hydrophilic balance of the mesoporous SBA-15 silica materials. For comparison, short and long time conventional muffle furnace calcination was performed. The induction calcination was also successfully applied to different type of mesoporous silica materials such as SBA-16 and MCM-41.     

氨基功能化介孔硅吸附剂的制备及其对铬(Ⅲ)的吸附行为

采用3-氨丙基三甲氧基硅烷（APTMS）对SBA-15介孔硅进行改性，获得氨基功能化介孔硅吸附剂（NH₂-SBA-15），从而赋予其螯合重金属离子的能力。利用XRD、SEM、TEM、EDX、TGA、BET和XPS等手段对吸附剂的表面形貌、孔道结构、元素分布和表面化学性质进行了表征。研究了NH₂-SBA-15吸附剂对水溶液中铬(Ⅲ)的吸附性能，分析了吸附动力学、吸附热力学和再生性能。结果表明，SBA-15吸附剂经过氨基功能化后，其原有的结晶结构没有明显变化，且对铬(Ⅲ)的吸附性能显著提高。NH₂-SBA-15对铬(Ⅲ)的吸附行为符合Langmuir等温吸附模型和拟二级吸附动力学方程。NH₂-SBA-15对铬(Ⅲ)的吸附过程主要依靠其表面—NH₂与铬(Ⅲ)的配位螯合作用，且为吸热过程。经过5次循环利用后，NH₂-SBA-15对铬(Ⅲ)的吸附率仍然保持在92%以上。该氨基功能化介孔硅吸附剂在吸附铬(Ⅲ)方面具有潜在的应用前景。     

Vanadium-containing ordered mesoporous silicas: Synthesis, characterization and catalytic activity in the hydroxylation of biphenyl

A series of vanadium-containing ordered mesoporous MCM-41 materials (V-OMS) have been synthesized by direct hydrothermal (V-MCM-41) and grafting (V/MCM-41) methods using hexadecyl trimethyl ammonium bromide (HDTMABr) as the structure-directing agent. The physico-chemical properties of the vanadium-containing materials were characterized in detail by ICP-OES, XRD, FT-IR, N₂ adsorption–desorption, DRUV-VIS, TPR, XPS and SEM techniques. The redox performances of the vanadium-modified mesoporous materials were tested in the hydroxylation of biphenyl using aqueous H₂O₂ (30 wt.%) as oxidant. For a better exploitation of the catalytic activity, the reaction parameters are optimized in terms of temperature, solvent, oxidant, etc. A comparison between the catalytic activity values of the vanadium-containing mesoporous materials prepared by the two routes shows that vanadium-substituted (V-MCM-41) materials had increased activity and improved selectivity for mono hydroxyl products in the hydroxylation reaction of biphenyl compared to the V/MCM-41 catalysts. The heterogenity of the catalysts was verified by a series of leaching studies. Both the catalysts enhance the leaching of active vanadia species during the reaction; among them, V/MCM-41 shows the least heterogenity.     

Highly Effective Oxidative Dehydrogenation of Propane Over Vanadia Supported on Mesoporous SBA-15 Silica

Vanadia-containing mesoporous SBA-15 catalysts were prepared and characterized for the oxidative dehydrogenation (ODH) of propane. It is demonstrated that the vanadia-supported SBA-15 catalysts exhibit a much higher catalytic activity than those reported in the literature obtained over vanadium-supported mesoporous MCM-41 catalysts in the ODH of propane. The high catalytic performance of the mesoporous SBA-15 catalysts is attributed to the particularly large pore diameters and low surface acidity.