Al-SBA-15介孔分子筛的合成、表征及其在苯酚叔丁基化反应中的催化性能

 通过嫁接的方法合成了Al-SBA-15介孔分子筛,用X射线衍射、透射电子显微镜、低温N2吸附和NH3程序升温脱附等方法进行了表征,并研究了其在苯酚叔丁基化反应中的催化性能. 结果表明, Al-SBA-15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,且在苯酚叔丁基化反应中表现出比Al-MCM-41更好的催化活性和2,4-二叔丁基苯酚选择性.     

H5PMo10V2O40/SBA-15催化剂的制备及其催化性能

以Keggin型杂多酸H5PMo10V2O40为主体,SBA-15介孔分子筛为载体,利用溶胶-凝胶法制备了不同负载量的H5PM10V2O40/SBA-15负载型催化剂,通过XRD、FTIR、TEM、H2-TPR和N2吸脱附法对样品进行了分析和表征,并将制得的负载型催化剂应用于苯氧化苯酚的反应中,研究了不同条件(温度、时间和催化剂用量等)下的催化性能.研究结果表明:H5PMo10V2O40杂多酸能均匀地分散于SBA-15孔道中且SBA-15的六方介孔结构并未发生改变:较好地解决了活性组分大量溶脱的问题;与H5PMo10V2O40杂多酸相比,H5PMo10V2O40/SBA-15催化剂在苯氧化为苯酚的反应中具有更高的转化率和更好的选择性,当反应温度为70℃,催化剂的使用量为0.25 g,反应时间为2 h和H5PMo10V2O40负载量为60%时苯酚的选择性达到了82.53%.     

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。     

8-羟基喹啉铜(Ⅱ)功能化SBA-15的制备、表征及催化性质

利用3-氨丙基功能化的介孔SBA-15(APS-SBA-15)作为载体, 通过C—N共价键将8-羟基喹啉铜(Ⅱ)固定到APS-SBA-15孔道中, 制备了8-羟基喹啉铜(Ⅱ)功能化的SBA-15催化剂[Cu(Ⅱ)-Q-APS-SBA-15], 并将其用于以质量分数30%的过氧化氢为氧化剂的苯酚羟化反应中. 结果表明, Cu(Ⅱ)-Q-APS-SBA-15呈现出较高的苯酚转化率和苯二酚选择性.     

CuO/Al-SBA-15催化剂的合成及其对苯酚羟基化反应的催化性能

采用不同硅铝比的介孔分子筛(Al-SBA-15)作为载体负载不同量的铜元素作为催化剂(CuO/AlSBA-15),通过小角X射线衍射、氮气吸附脱附等温线表征其结构性质,并以苯酚羟基化的反应为模型反应考察了材料的催化性能。研究发现,高的铜负载量不利于介孔材料结构的保持,在较低的铜负载量(3%)的情况下就可以使苯酚羟基化达到61.2%的高转化率。通过对Al-SBA-15和SBA-15作为载体的催化剂的循环套用分析,发现Al-SBA-15作为载体经过5次套用之后依然保持着57.9%的高转化率,而SBA-15经5次套用后的转化率仅有43.6%。这种结果应该得益于载体中的铝元素增加了材料表面的电荷,使铜离子与载体的相互作用加强,在循环套用中的铜离子在材料表面的分散更均匀。     

巯基功能化介孔材料高效锚定钯负载型催化剂的制备及其苯酚加氢催化性能

以含巯基官能团有机硅烷修饰的介孔材料MCM-41和SBA-15为载体, 采用浸渍-氢气还原法制备了高分散和高活性的负载型Pd催化剂. X射线衍射、N₂吸附-脱附和透射电子显微镜表征结果显示, 所制Pd催化剂Pd-SH-MCM-41和Pd-SH-SBA-15具有很好的长程有序结构、分布均匀的孔径、高比表面积及高度分散的Pd颗粒. 苯酚加氢反应结果表明, 以Pd-SH-MCM-41和Pd-SH-SBA-15为催化剂时, 在80℃, 1.0MPa反应1h, 苯酚转化率达99%以上, 环己酮选择性为98%. 它们的催化活性为商业Pd/C催化剂的5倍, Pd/MCM-41和Pd/SBA-15催化剂的3倍. 这可归因于介孔材料表面修饰的巯基官能团对Pd的锚定作用, 避免了Pd颗粒的团聚, 使其高度分散在介孔材料上.     

Cu/SBA-15-SO3H催化木糖一锅转化制备糠醇（英文）

糠醇是一种重要的高附加值化学品,目前工业上由含半纤维素或木聚糖的生物质原料经过酸脱水先制备糠醛,糠醛再进一步加氢制备糠醇.在实际生产中,这两步反应分别在不同的设备中进行,增加了分离纯化和运输成本;目前也很少有研究偶联这两步反应.本工作中,我们制备了一种多功能介孔Cu/SBA-15-SO3H催化剂用于一锅法一步转化木糖到糠醛,并且通过X射线粉末衍射(XRD)、透射电子显微镜(TEM)、傅里叶变换红外光谱(FT-IR)、热重分析(TGA)、电感耦合等离子体发射光谱(ICP-OES)、X射线荧光(XRF)、NH3-程序升温脱附(NH3-TPD)和N2物理吸附等表征检测了负载的酸和金属位点的可用性以及催化剂的物理化学性质,优化了反应温度、氢气压力、反应时间和溶剂体系等反应条件,研究了酸和金属位点的比例以及介孔尺寸对合成糠醇的影响.XRD表征和TEM及HRTEM图像均表明,在负载了磺酸和Cu之后,均会一定程度上破坏SBA-15的形貌,但是依然可以保持原本的有序介孔结构.XPS表明还原后的Cu主要以+1价的形式存在,也有少量的0价和+2价.红外光谱表明磺酸基团和SBA-15载体以共价键形式紧密结合.氮气吸脱附和相关的BET和BJH计算表明,我们的原位制备方法相比于传统浸渍法,磺酸位点的含量提高了7倍以上.通过对反应条件的优化,该体系在140℃和4MPaH2下可以实现62.6%的糠醇收率.过高的温度会引起产物过度加氢生成2-甲基呋喃,而过高的压力会导致原料过度加氢生成木糖醇.合适的溶剂也是反应的关键因素,使用1:3的水/丁醇双相体系,一方面可以有效促进糖的溶解,另一方面可以有效萃取产物,保证了反应的碳平衡.在对催化剂的筛选中发现,单独的SBA-15几乎无催化活性,Cu/SBA-15主要催化木糖加氢生成木糖醇,SBA-15-SO3H主要催化木糖脱水生成糠醛,而物理混合的Cu/SBA-15和SBA-15-SO3H的效率远不如双功能Cu/SBA-15-SO3H催化剂.通过调节磺酸含量和探究产物时间曲线发现,提高酸性位点可以促进木糖转化,但是过多的酸性位点会导致结焦,降低糠醇收率.共同存在的磺酸酸性位点和铜金属位点保持平衡,协同催化串联反应进行.通过调节SBA-15的孔道结构发现,4 nm的孔道最适合反应进行,孔道过大会降低反应的整体碳收率和糠醇收率.本催化体系实现了从木糖一锅多步法制糠醇,并对催化剂的构效关系进行了研究,对反应条件进行了系统的优化,有希望实际应用到糠醇生产中.     

Fe-MSU-1介孔分子筛的合成及其催化苯酚羟基化性能

以月桂醇聚氧乙烯醚为模板剂,在中性条件下成功合成了Fe-MSU-1介孔分子筛.采用X射线衍射、傅里叶变换红外光谱、紫外-可见吸收光谱、电子自旋共振谱、透射电镜、低温N2吸附和电感耦合等离子体原子发射光谱对样品进行了表征.考察了Fe-MSU-1分子筛在苯酚羟基化反应中的催化性能以及工艺条件对苯酚羟基化反应的影响.结果表明,Fe3 离子进入了分子筛骨架,Fe-MSU-1分子筛具有均一的蠕虫状介孔结构,平均孔径约为2.9nm.在焙烧后的Fe-MSU-1样品中,Fe3 主要以四配位的形式存在,无骨架外Fe2O3物种形成.以水为溶剂,在苯酚/H2O2摩尔比为3,反应温度353K,反应时间7h的条件下,苯酚和H2O2的转化率以及苯二酚的选择性分别达到20.4%,96.9%和99.6%.     

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.     

金复合介孔SBA-15吸附血红蛋白在H2O2电催化反应中的应用

以P123嵌段共聚物表面活性剂为模板剂制备介孔氧化硅SBA-15,并用沉积-沉淀(DP)法在SBA-15介孔表面负载纳米Au颗粒制备得到金复合介孔SBA-15材料(Au-SBA-15).再以Au-SBA-15材料制备玻碳修饰电极,将血红蛋白固定于修饰电极上用循环伏安法考察其对不同浓度H2O2溶液的电催化反应.在固定了血红蛋白的Hb/Au-SBA-15/GC修饰电极上,H2O2在+0.95 V处出现了氧化峰,且随着H2O2浓度的增大峰电流不断增加,说明金复合介孔氧化硅材料具有良好的生物兼容性,有利于血红蛋白的固定,其修饰电极对H2O2溶液具有一定的电催化作用.     

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.     

表面含磺酸基的介孔分子筛催化剂SBA-15-SO3H的制备及其催化性能

采用直接和后合成两种方法制备出含磺酸基的介孔分子筛SBA-15-SO₃H,用XRD和红外光谱分析制备过程中催化剂结构和组成的变化.结果表明,两种方法制备出的含磺酸基的催化剂都保持了SBA-15分子筛的完整晶体结构,并含有质子酸中心-SO₃H;固体核磁共振表征结果证明,两种方法都使MPTMS存在于分子筛的表面;用N₂吸附-脱附测定了它们的比表面积、孔径和孔容;TGA分析认为,MPTMS在分子筛表面的热稳定性大于300℃,酸碱滴定结果说明,直接法获得的催化剂的酸中心多于后合成法.酯化反应结果表明,直接法合成的催化剂比后合成法具有更高的稳定性,且简便、快捷、高效.     

Beta沸石上合成对叔丁基苯酚和2,4—二叔丁基苯酚

首次在三相条件下,在Ｂｅｔａ沸石催化剂上研究了苯酚与异丁烯烷基化合成对叔丁基苯酚和２,４－二叔丁基苯酚。通过对Ｈｂｅｔａ沸石高温焙烧和吡啶中毒试验研究了烷基化反应活性和选择性的变化规律;用ＮＨ３－ＴＰＤ和Ｐｙ－ＩＲ测定了试样的酸量和酸种类,结果表明Ｈｂｅｔａ沸石具有很好的烷基化活性,苯酚的转化率可达９２％,经１１２３Ｋ焙烧后苯酚转化率为８８％,对叔丁基苯酚和２,４－二叔丁基苯酚的选择性分别为７０～７５％和１４～２０％,中等强度的Ｂｒｎｓｔｅｄ酸是苯酚与异丁烯烷基化反应的活性中心。粘合剂含量低于３０％对烷基化活性基本无影响     

Mg/Ce-SBA-15的制备及其苯酚甲醇烷基化性能的研究

以Ce-SBA-15为载体,硝酸镁为活性组分前驱体,通过浸渍法制备了Mg/Ce-SBA-15催化剂。利用XRD、N₂吸附-脱附、SEM、EDS、NH₃-TPD、Py-FTIR和TG-DTA手段对催化剂进行表征。结果表明,Mg掺杂并未破坏载体结构,催化剂表面弱酸含量有所增加,L酸增加明显。在固定床反应器中评价了Mg/Ce-SBA-15分子筛催化苯酚甲醇烷基化的反应性能。结果表明,Mg负载量为7%、焙烧温度为550℃、焙烧时间为4.5 h制备的Mg/Ce-SBA-15催化剂催化效果最佳。在反应温度460℃,n（苯酚）：n（甲醇）为1：4,质量空速为3.0 h^-1,常压的条件下,苯酚转化率为80.1%,邻甲酚选择性为86.4%。     

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.     

Synthesis, characterization, and luminescence properties of the ternary europium complex covalently bonded to mesoporous SBA-15

A novel mesoporous SBA-15 type of hybrid material (phen-SBA-15) covalently bonded with 1,10-phenanthroline (phen) ligand was synthesized by co-condensation of tetraethoxysilane (TEOS) and the chelate ligand 5-[N,N-bis-3-(triethoxysilyl)propyl]ureyl-1,10-phenanthroline (phen-Si) in the presence of Pluronic P123 surfactant as a template. The preservation of the chelate ligand structure during the hydrothermal synthesis and the surfactant extraction process was confirmed by Fourier transform infrared (FTIR) and (29)Si MAS NMR spectroscopies. SBA-15 consisting of the highly luminescent ternary complex Eu(TTA)(3)phen (TTA = 2-thenoyltrifluoroacetone) covalently bonded to a silica-based network, which was designated as Eu(TTA)(3)phen-SBA-15, was obtained by introducing the Eu(TTA)(3).2H(2)O complex into the hybrid materials via a ligand exchange reaction. XRD, TEM, and N(2) adsorption measurements were employed to characterize the mesostructure of Eu(TTA)(3)phen-SBA-15. For comparison, SBA-15 doped with Eu(TTA)(3).2H(2)O and Eu(TTA)(3)phen complexes and SBA-15 covalently bonded with a binary europium complex with phen ligand were also synthesized, and were named SBA-15/Eu(TTA)(3), SBA-15/Eu(TTA)(3)phen, and Eu-phen-SBA-15, respectively. The detailed luminescence studies on all the materials showed that, compared with the doping sample SBA-15/Eu(TTA)(3)phen and binary europium complex functionalized sample Eu-phen-SBA-15, the Eu(TTA)(3)phen-SBA-15 mesoporous hybrid material exhibited higher luminescence intensity and emission quantum efficiency. Thermogravimetric analysis on Eu(TTA)(3)phen-SBA-15 demonstrated that the thermal stability of the lanthanide complex was evidently improved as it was covalently bonded to the mesoporous SBA-15 matrix.     

Effect of aluminum modification on catalytic properties of PtSn-based catalysts supported on SBA-15 for propane dehydrogenation

The catalytic properties of PtSn-based catalysts supported on siliceous SBA-15 and Al-modified SBA-15, such as Al-incorporated SBA-15 (AlSBA-15) and alumina-modified SBA-15 (Al2O3/SBA-15), for propane dehydrogenation were investigated. Al2O3/SBA-15 was prepared either by an impregnation method using aluminum nitrate aqueous solution, or by the treatment of SBA-15 with a Al(OC3H7)3 solution in anhydrous toluene. N2-physisorption, FT-IR spectroscopy, solid-state 27Al MAS NMR spectroscopy, hydrogen chemisorption, XRF, NH3 temperature-programmed desorption, X-ray photoelectron spectroscopy and TPO were used to characterize these samples. Among these catalysts, the PtSn-based catalyst supported on Al2O3/SBA-15, which was grafted with Al(OC3H7)3, exhibited the best catalytic performance in terms of activity and stability The possible reason was due to the high Pt metal dispersion and/or the strong interactions among Pt, Sn, and the support.     

Synthesis, characterization, and catalytic performance of copper-containing SBA-15 in the phenol hydroxylation

A series of copper-containing SBA-15 samples were successfully synthesized via evaporation-induced self-assembly route. The resulting materials were characterized by X-ray diffraction (XRD), (29)Si MAS NMR spectroscopy, transmission electron microscopy (TEM), N(2) sorption, inductively coupling plasma-atomic emission spectrometer (ICP-AES), thermogravimetry, and differential thermal analysis (TG-DTA), Fourier-transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectra (UV-vis) and X-ray photoelectron spectroscopy (XPS). The results indicated that: (1) all the samples exhibited typical hexagonal arrangement of mesoporous structure; (2) copper ions could be incorporated into the framework of SBA-15; (3) the addition of urea in the hydrothermal stage efficiently reduced the leaching of copper and improved the thermal stability of the mesoporous materials. Catalytic performances of the obtained materials were evaluated in the hydroxylation of phenol with H(2)O(2). The catalytic tests showed that the synthesized materials exhibited high activity for this reaction and copper ions in the framework were more active than copper species in the extra-framework position. The nitric acid treatment on the samples removed the bulk CuO species, which resulted in a dramatic increase in the catalytic activity.