含钨SBA-15介孔分子筛催化剂的表面酸性和羟基分布

分别以浸渍法和水热晶化法制备了SBA-15介孔分子筛孔中插入氧化钨和碳化钨的催化剂,采用NH3-TPD测定了表面酸性和总酸量,并采用FT-IR研究了它们的表面羟基分布情况.NH3-TPD结果表明,浸渍法制备的含氧化钨的SBA-15介孔分子筛催化剂表面只有SBA-15介孔分子筛的弱酸位,而含碳化钨的SBA-15介孔分子筛催化剂表面还出现了W2C的强酸位.水热晶化法制备的含氧化钨的SBA-15介孔分子筛催化剂表面SBA-15介孔分子筛的弱酸位随W含量的增大略有增强, W含量较高时还出现了钨物种的强酸位;含碳化钨的SBA-15介孔分子筛催化剂表面除了SBA-15介孔分子筛的弱酸位外, W含量较低时有W2C的强酸位, W含量较高时有W2C和WC两种强酸位.傅里叶变换红外光谱结果表明,浸渍法和水热晶化法制备的含氧化钨和碳化钨的SBA-15介孔分子筛催化剂除表面自由硅羟基外,还存在着α, β和γ三种不同类型的氢键羟基,并且氢键羟基和催化剂的制备方法以及催化剂的W含量都有一定的关系.     

疏水双功能介孔固体酸的合成及其在乙酸乙酯酯化反应中的应用

通过水热合成法一步合成了具有不同疏水基团－CH₃ 、－(CH₃)₂ 和－(CH₃)₃的双功能介孔固体酸SBA-15-SO₃H－(CH₃)_x催化剂。通过X射线粉末衍射(XRD)、N₂吸脱附、元素分析等方法对催化剂进行了表征,并在乙酸乙酯酯化反应中进行催化性能评价。结果表明,随着疏水前驱体中甲基数的增加,样品的疏水性增强。SBA-15-SO₃H-(CH₃)_x催化剂的催化活性随着疏水性的增强而提高,而具有较强疏水性的材料SBA-15-SO₃H-(CH₃)₃在反应中具有较高的催化性能。以SBA-15-SO₃H-(CH₃)₃为催化剂,酯化反应的最优条件为：温度为120℃,乙酸与乙醇摩尔比为4∶1,催化剂质量分数为1 %,反应时间为1h。在此条件下,乙醇的转化率和乙酸乙酯的选择性分别为93%和100%。     

SBA-15介孔分子筛表面的磺酸基改性及其催化性能

 采用后合成方法，将含有巯基的化合物3－巯丙基三甲氧基硅烷（MPTMS）键合在大孔径、厚孔壁的新型纯硅介孔分子筛SBA－15表面上，经氧化和酸化后得到含有强酸性的磺酸基团的固体酸催化剂SBA－15－SO3H．用X射线衍射、红外光谱、固体核磁共振及热失重等方法对改性前后的SBA－15样品进行了表征．结果表明，改性后SBA－15分子筛的结构未发生变化，MPTMS键合于分子筛的表面，改性后的分子筛具有质子酸中心．SBA－15－SO3H催化剂对十八碳烯酸与甲醇的酯化反应具有较高的活性，催化剂上的磺酸基团在反应过程中具有较好的稳定性．     

BiVO_4/SBA-15催化剂的制备及其光催化氧化脱硫性能

采用水热后合成法制备了BiVO_4/SBA-15催化剂,利用XRD、SEM-EDS和N2吸附-脱附等手段对其进行表征分析,并在自制的光催化反应装置中对其静态光催化氧化脱硫性能进行了研究。结果表明,BiVO_4/SBA-15催化剂具有SBA-15分子筛的介孔孔道结构,BiVO_4均匀分布在SBA-15分子筛表面。BiVO_4/SBA-15催化剂具有良好的催化氧化脱硫性能,在BiVO_4负载量为15%、水热合成时间为18 h、530℃下焙烧3 h制备的BiVO_4/SBA-15催化剂,对模拟柴油的脱硫率可达95.6%。     

表面含磷酸的介孔分子筛P-SBA-15的合成及其性能评价

采用后合成法，将磷酸固载在纯硅介孔分子筛SBA-15表面上。利用X射线衍射（XRD）、红外光谱（IR）、氮气吸附 脱咐法（BET）分析方法表征催化剂的物理性能。结果表明，催化剂P-SBA-15在高温焙烧后保持了稳定的介孔分子筛SBA-15结构，该催化剂的比表面积和孔径分别为605.45m2/g和5.576nm（磷硅摩尔比5%）。选用十一碳烯酸与异丙醇的酯化反应对催化剂P-SBA-15的催化反应性能进行评价，同时与其他几种微孔沸石分子筛催化剂催化性能相比表明，磷酸改性的介孔分子筛P SBA 15是合成十一烯酸异丙酯较为理想的固体酸催化剂，考察了催化剂的稳定性。     

铝修饰改性对SBA-15分子筛性质及催化剂性能的影响

分别采用调变pH值合成法和后处理嫁接法制备了铝修饰改性的SBA-15分子筛,通过XRD、Al核磁、N₂吸附脱附、NH₃-TPD等方法对改性分子筛的理化性质进行了分析表征,考察了不同的Al修饰改性方法对分子筛性质和加氢裂化催化剂性能的影响。结果表明,调变pH值合成法能够有效地对SBA-15进行Al改性,得到的Al-SBA-15分子筛具有高度有序的六方孔道结构,较好的水热稳定性。Al的引入提高了SBA-15的表面酸性,并使其在加氢裂化反应中表现出较好的中油选择性。     

表面含磺酸基的介孔分子筛SBA-15-SO3H的直接合成

 采用水热法直接合成了含磺酸基的介孔分子筛SBA－15－SO3H．XRD表征结果表明，该分子筛具有规则的、六方立柱形的中孔结构，通过酸碱滴定和XRD确定了正硅酸乙酯／有机硅的最佳合成配比为9（α＝0．1）．29SiMASNMR固体核磁结果表明，含磺酸基的有机基团Si－（CH2）3－SO3H中的硅与SBA－15骨架上的氧通过Si－O键结合，形成稳定的有机／无机组成，FT－IR谱表明：在SBA－15－SO3H表面含有质子酸中心－SO3H．N2吸附－脱附和TEM结果表明，SBA－15－SO3H具有较大的比表面积、孔容和孔径，孔大小是单一的，孔分布是高度有序的．酯化反应结果表明，与后合成法相比，直接法合成的催化剂既具有较高的稳定性，又具有简便、快捷和高效的优点．     

Hβ/Al-SBA-15介微孔复合分子筛负载Ni-W催化剂对萘加氢裂化制BTX的催化性能

采用后合成法制备Hβ/Al-SBA-15复合分子筛,利用XRD、N_2吸附、Py-IR、NH_3-TPD、SEM和TEM等手段进行表征。用浸渍法将Ni-W活性组分担载在Hβ/Al-SBA-15载体上,制备Ni-W/Hβ/Al-SBA-15催化剂,以萘为模型化合物,考察该催化剂的加氢裂化性能。结果表明,所合成的Hβ/Al-SBA-15复合分子筛既有介孔结构又有微孔结构,并同时具有B酸和L酸中心,酸性强于SBA-15。具有适度酸性位和介微孔结构的Ni-W/Hβ/Al-SBA-15催化剂,对萘加氢裂化具有较高的萘转化率和BTX选择性,分别为96%和61.1%。     

微孔-介孔复合分子筛HY-SBA-15的表征及应用

用后合成法制备了微孔-介孔复合分子筛HY-SBA-15(y) (y表示HY与SBA-15的质量比)。并用XRD、FT-IR、N₂吸脱附及NH₃-TPD等技术对HY-SBA-15进行表征。结果表明,HY-SBA-15既具有微孔结构又具有介孔结构,当y=0.10时,微孔与介孔混合晶相显著,且HY-SBA-15(0.10)复合分子筛具有B酸和L酸,酸性强于HY。用浸渍法将Ni-W活性组分担载在HY-SBA-15(0.10)载体上,制备加氢脱芳烃催化剂Ni-W/HY-SBA-15(0.10),选用茂名石化FCC柴油为原料,考察了催化剂的加氢脱芳烃性能。实验结果表明,Ni-W/HY-SBA-15(0.10)催化剂具有良好的芳烃加氢饱和性能和开环活性。     

硅烷偶联剂改性SBA-15固载Keggin型杂多酸催化合成柠檬酸三丁酯

以3-(甲基丙烯酰氧)丙基三甲氧基硅烷(MEMO)表面改性的介孔分子筛SBA-15为载体,制备了一系列介孔分子筛/硅烷偶联剂@杂多酸复合催化剂SBA-15/MEMO@HnXW12O40(X=P⁵+,Si⁴⁺,B³⁺;n=3,4,5),并利用FTIR、P-XRD、TEM、N2吸附-脱附对其结构进行表征。以SBA-15/MEMO@HnXW12O40(X=P⁵⁺,Si⁴⁺,B³⁺;n=3,4,5)为负载型杂多酸催化剂对柠檬酸三丁酯的催化合成进行研究,分别考察了酸醇摩尔比、催化剂用量、反应温度、反应时间对催化合成柠檬酸三丁酯酯化率的影响,并获得合成柠檬酸三丁酯的最佳工艺条件。结果表明:当负载型硅钨酸催化剂的负载量为50%、催化剂用量为3.8%、酸醇摩尔比为1∶4、反应温度为140℃、反应时间为6 h、环己烷用量为5 mL时酯化率可达97.56%,重复使用7次后酯化率仍可达62.67%。     

介孔分子筛SBA-15-SO3H催化合成油酸甲酯

在成功合成出含磺酸基的介孔分子筛SBA-15-SO3H的基础上，用于油酸与甲醇的酯化反应，考察该催化剂的催化性能，结果表明：在高级脂肪酸的酯化反应中，SBA-15-SO3H催化剂的活性高于沸石分子筛，与等摩尔数的硫酸的活性接近。考察了反应条件对SBA-15-SO3H催化剂性能的影响，得到油酸与甲醇酯化反应的最佳条件：反应温度60 ℃，甲醇与油酸的原料比为2∶1（摩尔），催化剂与原料比为1.5∶35（重量）。最后对催化剂的稳定性进行了考察，反应结果认为该催化剂在重复使用过程中活性未发生明显变化，反应前后的XRD分析结果认为，SBA-15-SO3H具有较高的水热稳定性。     

Preparation, characterization and catalytic activity towards green reactions of sulfonic functionalized SBA-15

Acidic heterogeneous catalysts based on the anchorage of sulfonic groups on SBA-15 mesoporous silica were synthesized. In a first synthesis step, samples containing mercapto groups were prepared by co-condensation of tetraethylorthosilicate with 3-mercaptopropyltrimethoxysilane, in presence of ethylene-propylene block copolymer as mesoporous silica structure director. In other samples, mercapto groups were introduced by post-functionalization of the traditional calcined SBA-15. In a second step, these mercapto groups were oxidized in order to get sulfonic acid groups on the surface. Characterization of the samples was carried out by N₂ adsorption-desorption, FTIR, XPS and acid-base titration. Spectroscopic techniques showed that the effective incorporation of sulfonic groups depends on the synthesis methodology used. In turn, the SBA-15 post-synthesis functionalization produces changes in structural characteristics like a decrease in BET surface and changes in the pore size distribution. The as-prepared materials were tested as acid catalysts in the alkylation of isobutane with 1-butene, and in the esterification of free fatty acids with methanol. The results obtained show a lack of activity in the alkylation reaction which can be associated with the formation and stabilization of the intermediate carbocation species.     

磺酸基团功能化的碳-硅介孔复合材料的制备及其在生物柴油绿色合成中的应用(英文)

利用化学浸渍法将蔗糖负载到 SBA-15 介孔材料孔道内部, 高温炭化形成的多聚苯环经发烟硫酸气相磺化处理后, 得到磺酸基团功能化的新型碳-硅介孔复合材料. 发烟硫酸气相磺化处理是该材料合成的关键步骤. X 射线衍射、扫描电镜和氮气吸附结果表明, 碳-硅介孔复合材料经磺酸化处理保持了高度有序的介孔结构. 热重、傅里叶变换的红外光谱及吡啶吸附红外光谱结果证明, 磺酸功能基团成功的嫁接于碳-硅介孔复合材料孔道的内表面, 反应活性中心为 Br?nsted 酸, 酸密度在 0.09~0.70 mmol/g 可以有效调变. 当碳负载量为 35% 时, 该复合材料在生物柴油的绿色合成中显示出最优的催化性能, 且可重复使用 3 次以上.     

磺酸基功能化的有序SBA-15-SO3H介孔分子筛的合成及其在苯酚叔丁基化反应中的应用

通过一步法合成了SBA-15-SO3H介孔分子筛,用XRD,TEM,低温N2吸附和吡啶吸附红外光谱等方法进行了表征,并研究了其在苯酚叔丁基化反应中的催化性能.结果表明,SBA-15-SO3H保持了母体SBA-15高度有序的六方介孔结构,具有较强的酸性和热稳定性,且在苯酚叔丁基化反应中表现较好的催化活性和2,4-二叔丁基苯酚选择性.     

Synthesis, characterization and catalytic behavior of functionalized mesoporous SBA-15 with various organo-silanes

Mesoporous silica SBA-15 has been synthesized and functionalized by one-step synthesis method to widen their various application possibilities. In this study, phenyltrimethoxysilane (PTMS), 3-mercaptopropyltrimethoxysilane (MPTMS) and trimethoxypropylsilane (TMPS) were used as silane precursors for the functionalization, and after treated with HCl solution, their catalytic activities were evaluated in the lactic acid-methanol esterification. The presence of anchoring of functional groups on SBA-15 was proved by XRD, FT-IR, BET surface area and pore size distributions. Good catalytic activity was observed especially for SBA-15-SO(3)H-MPTMS, and the catalytic activity order was determined as follows: SBA-15-SO(3)H-MPTMS>SBA-15-TMPS>SBA-15-PTMS, which is directly associated with the surface area, pore size and pore volume. As compared with homogeneous catalyst, SBA-15-SO(3)H-MPTMS heterogeneous catalyst shows remarkable performance, such as separation, recovery and reusability.     

磺酸功能化三维有序大孔材料的制备与催化性能研究

采用模板法, 用正硅酸乙酯和3-巯丙基-三甲氧基硅烷的混合溶胶, 在聚苯乙烯胶晶间隙中原位转化, 除去模板后用双氧水将巯基氧化成磺酸基, 首次成功地制备了大孔规整排列的3DOM SiO₂-SO₃H材料. 样品用SEM, EDS, FT-IR等方法进行了测试表征. 结果表明, 所得到材料的三维大孔结构规整性十分好, 大孔孔径大约250 nm, 并由大约80 nm的小孔相连; 磺酸基很好地嵌入孔壁基质中, 吡啶吸附测定显示了典型的质子酸特征, 而且酸中心随硫含量增加而增多. 对乙酸与正丁醇的酯化反应显示了良好的催化性能, 磺酸含量越大, 催化活性越高. 这一研究为开发新型高效的固体酸催化剂提供了很有意义的结果.     

Functionalized SBA-15 and its Catalytic Applications in Selective Organic Transformations

Ordered, mesoporous SBA-15 functionalized with organic and inorganic moieties exhibits efficient catalytic activity in a variety of organic transformations. In this account, reviewing our own work, three-sets of surface-modified SBA-15 materials have been investigated. The first-set of materials consists of SBA-15 modified with organo-acidic (propyl thiol and propyl sulfonic acid) and basic (propyl amine and propyl adenine) moieties. The second-set of materials was prepared by grafting Mn complexes to the organo-functionalized SBA-15. The third-set composes of nanocrystalline metal oxides supported on SBA-15. All these catalysts have been characterized by structural and spectroscopic techniques. Catalytic activities of the first-set of solid materials have been investigated in acid/base-catalyzed reactions viz., ring-opening of epoxides with amines (producing β-amino alcohols), esterification, three-component-Mannich reactions and cycloaddition of CO₂ to epoxides. The Mn complexes grafted on organofunctionalized SBA-15 are efficient catalysts for the chemo-, regio- and stereoselective aerial oxidation of monoterpenes at ambient conditions. TiO_x, VO_x, MoO_x and WO_x supported on SBA-15 catalyzed biomimetic oxyhalogenation of aromatic compounds. In all these reactions, the functionalized SBA-15 showed high selectivity.     

Synthesis and solid-state NMR characterization of cubic mesoporous silica SBA-1 functionalized with sulfonic acid groups

Well-ordered cubic mesoporous silicas SBA-1 functionalized with sulfonic acid groups have been synthesized through in situ oxidation of mercaptopropyl groups with H(2)O(2) via co-condensation of tetraethoxysilane (TEOS) and 3-mercaptopropyltrimethoxysilane (MPTMS) templated by cetyltriethylammonium bromide (CTEABr) under strong acidic conditions. Various synthesis parameters such as the amounts of H(2)O(2) and MPTMS on the structural ordering of the resultant materials were systematically investigated. The materials thus obtained were characterized by a variety of techniques including powder X-ray diffraction (XRD), multinuclear solid-state Nuclear Magnetic Resonance (NMR) spectroscopy, (29)Si{(1)H} 2D HETCOR (heteronuclear correlation) NMR spectroscopy, thermogravimetric analysis (TGA), and nitrogen sorption measurements. By using (13)C CPMAS NMR technique, the status of the incorporated thiol groups and their transformation to sulfonic acid groups can be monitored and, as an extension, to define the optimum conditions to be used for the oxidation reaction to be quantitative. In particular, (29)Si{(1)H} 2D HETCOR NMR revealed that the protons in sulfonic acid groups are in close proximity to the silanol Q(3) species, but not close enough to form a hydrogen bond.     

Design of heterogeneous catalysts via multiple active site positioning in organic-inorganic hybrid materials

Catalytic materials bearing multiple sulfonic acid functional groups and positioned at varying distances from one another on the surface of mesoporous solids are prepared to explore the effects that the spatial arrangement of active sites have on catalytic activity and selectivity. A series of organosiloxane precursors containing either disulfide or sulfonate ester functionalities (synthons of the eventual sulfonic acid groups) are synthesized. From these molecular precursors, a variety of organic-inorganic hybrid, mesostructured SBA-15 silica materials are prepared using a postsynthetic grafting procedure that leads to disulfide and sulfonate ester modified silicas: [Si]CH(2)CH(2)CH(2)SS-pyridyl, 2.SBA, [Si]CH(2)CH(2)CH(2)SSCH(2)CH(2)CH(2)[Si], 3.SBA, [Si]CH(2)CH(2)(C(6)H(4))(SO(2))OCH(2)CH(3), 4.SBA, and [Si]CH(2)CH(2)(C(6)H(4))(SO(2))OC(6)H(4)O(SO(2))(C(6)H(4))CH(2)CH(2)[Si], 6.SBA ([Si] = (tbd1;SiO)(x)()(RO)(3)(-)(x)()Si, where x = 1, 2). By subsequent chemical derivatization of the grafted species, thiol and sulfonic acid modified silicas are obtained. The materials are characterized by a variety of spectroscopic ((13)C and (29)Si CP MAS NMR, X-ray diffraction) and quantitative (TGA/DTA, elemental analysis, acid capacity titration) techniques. In all cases, the organic fragment of the precursor molecule is grafted onto the solid without measurable decomposition, and the precursors are, in general, attached to the surface of the mesoporous oxide by multiple siloxane bridges. The disulfide species 2.SBA and 3.SBA are reduced to the corresponding thiols 7.SBA and 8.SBA, respectively, and 4.SBA and 6.SBA are transformed to the aryl sulfonic acids 11.SBA and 12.SBA, respectively. 7.SBA and 8.SBA differ only in terms of the level of control of the spatial arrangement of the thiol groups. Both 7.SBA and 8.SBA are further modified by oxidation with hydrogen peroxide to produce the alkyl sulfonic acid modified materials 9.SBA and 10.SBA, respectively. The performances of the sulfonic acid containing SBA-15 silica materials (with the exception of 12.SBA) are tested as catalysts for the condensation reaction of phenol and acetone to bisphenol A. The alkyl sulfonic acid modified material 10.SBA derived from the cleavage and oxidation of the dipropyl disulfide modified material 3.SBA is more active than not only its monosite analogue 9.SBA, but also the presumably stronger acid aryl sulfonic acid material 11.SBA. It appears that a cooperative effect between two proximal functional groups may be operating in this reaction.     

碳-硅复合介孔磺酸催化剂的制备及其在缩醛(酮)反应中的应用

采用浸渍法将糠醇负载在铝改性的SBA-15介孔孔道中,经550℃不完全碳化制备了结构规整、含多苯环的中空管状硅碳复合介孔材料.结果表明,通过温和磺酸化作用可使磺酸基团成功取代在多苯环上,其酸量随着多苯环涂层厚度变化在0.38~0.84 mmol/g范围内可控调变.相比于蔗糖作为糖源的复合固体酸,所制碳多苯环-硅酸催化剂具有中空碳纳米管堆积的类似CMK-5介孔结构,以及较大的反应空间、稳定的机械性能、较高的比表面和大量可以接触的质子酸中心,因而在大分子缩醛(酮)反应中表现了良好的催化性能.