TiO_2-SBA-15催化剂的制备、表征及光催化降解甲基橙

以钛酸四丁酯为钛源,以介孔分子筛SBA-15为载体,采用简单的方法制备TiO2-SBA-15催化剂,并采用FT-IR,XRD和N2吸附-脱附等方法对其进行表征.另外,将制备的TiO2-SBA-15催化剂应用于光催化降解甲基橙溶液,并讨论了钛含量、甲基橙浓度及溶液pH值对降解率的影响.结果表明:在钛酸四丁酯起始加入量为3.2mL,甲基橙浓度为10mg/L,溶液pH=3的条件下,TiO2-SBA-15光催化降解甲基橙的降解率可达到100%.     

氨基功能化SBA-15介孔分子筛的制备与表征

以3-氨丙基三乙氧基硅烷为偶联剂,采用后合成法对介孔分子筛(SBA-15)的表面进行改性,制得氨基功能化的介孔NH<,2>-SBA-15材料(简称NH<,2>-SBA-15),其结构和性能经FT-IR,元素分析,XRD,SEM及低温N<,2>吸附-脱附表征.结果表明,氨基成功地嫁接到SBA-15表面,含量高达3.47 ...     

外表面钝化SBA-15固载奎宁催化不对称Michael加成反应

以聚环氧乙烷-聚环氧丙烷-聚环氧乙烷三嵌段共聚物(P123)为模板剂制备SBA-15分子筛,将未除模板剂的SBA-15用三甲基氯硅烷钝化后固载奎宁制得外表面钝化CH_3-SBA-15-QN非均相催化剂.对非均相催化剂进行XRD、FT-IR、N_2吸附-脱附表征.并以查尔酮类化合物与丙二腈的不对称Michael加成反应为模型来考察非均相催化剂CH_3-SBA-15-QN的催化活性,实验结果表明,非均相催化剂CH_3-SBA-15-QN比SBA-15-QN催化剂对产物表现出较高的对映选择性.4-甲氧基查耳酮为底物时,CH_3-SBA-15-QN为催化剂时,产物对映选择性能够达到77%,甚至比均相催化剂高6%,充分发挥了载体孔道效应和手性催化剂的不对称诱导能力.     

SBA-15负载的Cu(Ⅱ)席夫碱配合物催化的苯乙烯氧化反应制备苯甲醛

采用一步法将原硅酸四乙酯与3-氨丙基三乙氧基硅烷在表面活性剂P123作用下,酸性共水解制备出氨基功能化的介孔分子筛SBA-15(NH2-SBA-15),再利用其中氨基与水杨醛的缩合反应制备SBA-15固载的席夫碱,该席夫碱与Cu(NO3)2溶液反应最终制成固定于SBA-15的Cu(II)席夫碱配合物多相催化剂Cu-SBA-15.采用X射线衍射、红外光谱仪、紫外可见分光光度计、场发射电镜、透射电镜、N2吸附-脱附、元素分析、原子发射光谱和热重分析对催化剂进行了表征,并将此催化剂用于无有机溶剂条件下催化氧化苯乙烯制备苯甲醛,考察了反应时间、反应温度、H2O2用量、水的用量、催化剂用量对反应的影响.当反应温度为100°C,反应时间8 h,H2O2与苯乙烯的摩尔比为2:1,不额外添加溶剂,且催化剂用量为3.8 wt%时,苯乙烯的转化率最高为84.4%,苯甲醛选择性为83.9%,催化剂的TOF值为261.1 h–1,并且重复使用3次后活性没有明显下降.规则的孔道、较大的比表面积以及分布均匀的活性中心可能是催化剂活性提高的原因.     

纳米介孔Ru-PPh2-SBA-16催化水相中高烯丙醇异构化反应的研究

以2-(二苯基膦)乙基三乙氧基硅烷和正硅酸乙酯为混合硅源, 采用延时共缩聚法经表面活性剂F127自组装合成了二苯基膦(PPh2)修饰的SBA-16纳米介孔分子筛(PPh2-SBA-16), 通过PPh2配体络合Ru(Ⅱ)化合物制备出固载化的Ru(Ⅱ)非均相催化剂(Ru-PPh2-SBA-16), 样品仍然保持了SBA-16的规整孔道结构. 以水相中高烯丙醇异构化反应为探针, 考察了所制备催化剂的催化性能, 发现其对目标产物具有高选择性, 虽然其催化活性略低于对应的均相Ru(Ⅱ)催化剂, 但该催化剂易与产物分离, 且重复使用三次后催化效率基本不变, 活性相与载体结合牢固, 不存在明显的脱落和流失, 因此更适合于工业化应用.     

SBA-15的孔壁碳膜修饰对钴基催化剂结构与催化性能的影响

在惰性气体中焙烧SBA-15制得孔壁被碳修饰的SBA- 15C样品,以它和SBA-15为载体,采用等量浸渍法制备了负载型Co基催化剂,并运用X射线衍射、N2物理吸附、程序升温还原、NH3吸附量热等手段对样品进行了表征.结果表明,SBA- 15C仍保持原有的六方有序的中孔结构,但其孔壁经碳修饰后发生增厚,比表面积略有下降...     

SBA-15固载磷钨酸催化剂的制备及催化性能

以SBA-15和氨基功能改性的SBA-15／NH2为载体,采用浸渍法制备了固载磷钨酸催化剂,通过FT—IR光谱,Raman光谱,XRD衍射分析,N2-吸附脱附实验,TEM和NH3-TPD等手段对催化剂进行表征．结果表明,磷钨酸在两种载体上均保持Keggin结构,载体的介孔结构没有明显破坏．在高固载量情况下,磷钨酸在SBA-15载体上发生晶相聚集,介孔孔道发生堵塞使比表面积、孔容和孔径明显减小．在SBA-15／NH2载体上,磷钨酸与载体发生酸碱作用,能够均匀分散于SBA-15／NH2的孔道中,但催化剂酸性有所降低．考察了相同固载量的两种催化剂对苹果酯合成反应的催化活性,结果表明,以SBA-15／NH2为载体的催化剂具有良好的重复使用性能．     

氨基功能化介孔二氧化硅对布洛芬的吸附和缓释性能研究

采用后合法对介孔二氧化硅SBA-15进行氨基改性,并以改性后材料NH2-SBA-15为载体,以疏水性药物布洛芬(IBU)为模型药物分子,通过浸渍法把IBU填充到载体的孔道内。利用XRD、低温N2吸附-脱附和FT-IR等测试手段,研究了载体的结构及载体与药物间的相互作用。结果表明,IBU通过扩散和化学吸附作用填充到了载体的孔道内,并且载体表面与IBU间存在较强的化学作用。体外模拟释放实验结果显示,与未改性的SBA-15相比,改性后样品NH2-SBA-15对IBU的释放较慢,体现了明显的药物缓释性能。     

低介电损耗苯并噁唑复合材料的合成与表征

对介孔二氧化硅SBA-15进行氨基官能团化,制得NH2-SBA-15,通过溶液缩聚合成了一系列具有不同SBA-15质量分数的聚亚苯基苯并二噁唑/SBA-15(PBO/SBA-15)复合材料。利用红外光谱(FT-IR)、扫描电子显微镜(SEM)、热重分析(TG)和矢量网络分析仪(VNA)分别对复合材料的结构、微观形貌、热性能和电磁性能进行了表征与分析,研究了SBA-15对PBO/SBA-15复合材料介电参数的影响。研究表明:经过氨基官能团化之后,SBA-15能够均匀地分散在PBO基体中;当复合材料中SBA-15的质量分数小于8%时,PBO/SBA-15复合材料仍然保持着PBO优异的热稳定性;介孔二氧化硅SBA-15能够有效地降低PBO/SBA-15复合材料的复介电常数和介电损耗角正切,减弱PBO/SBA-15复合材料对电磁波的介电存储和损耗能力,使PBO/SBA-15复合材料表现出低介电损耗的性能。     

ZSM-5-SBA-15复合分子筛制备及甲苯甲醇烷基化性能研究

采用后合成法制备了ZSM-5-SBA-15复合分子筛,通过XRD、FT-IR、BET、NH₃-TPD及吡啶红外等手段表征催化剂的性质。结果表明,ZSM-5-SBA-15既具有微孔结构又具有介孔结构。吡啶吸附和NH₃吸脱附实验结果表明,ZSM-5微孔分子筛的引入使SBA-15介孔分子筛的酸性增强,但与ZSM-5相比,ZSM-5-SBA-15复合分子筛的酸性位没有改变,酸强度有一定的减弱。用固定床评价了该复合分子筛甲苯甲醇烷基化反应的催化性能。结果表明,与常规ZSM-5相比,ZSM-5-SBA-15表现出了较高的对位选择性。     

Homoallylic alcohol isomerization in water over an immobilized Ru(II) organometallic catalyst with mesoporous structure

PPh(2)-functionalized SBA-15 was synthesized by co-condensation of tetraethyl orthosilicate and 2-(diphenylphosphino)ethyltriethoxysilane through prehydrolysis. The as-prepared PPh(2)-SBA-15 was used as the support to immobilize the Ru(II) organometallic catalyst through the strong coordination between the Ru(II) and the PPh(2)-ligand (Ru-PPh(2)-SBA-15). During 1-phenyl-3-buten-1-ol isomerization carried out in water as an environmentally friendly medium, the Ru-PPh(2)-SBA-15 catalyst exhibited almost the same activity and selectivity as the corresponding RuCl(2)(PPh(3))(3) homogeneous catalyst and could be used repetitively nearly 7 times. On the basis of various characterizations, the correlation of the catalytic behaviors of the Ru-PPh(2)-SBA-15 to its structural characteristics was discussed briefly. Obviously, the high activity of the Ru-PPh(2)-SBA-15 could be attributed to both the high surface area of the support, which ensured the good dispersion of Ru(II) active sites, and the ordered mesoporous structure, which facilitated the diffusion of organic reactants.     

Immobilization of acetylcholinesterase on functionalized SBA-15 mesoporous molecular sieve for detection of organophosphorus and carbamate pesticide

A novel method for the immobilization of acetylcholinesterase (AChE) on amino modified SBA-15 mesoporous molecular sieves was developed via electrostatic adsorption and glutaraldehyde crosslinking. The immobilized AChE could be exploited as a fast, sensitive and low-cost biocatalyst towards the detection of pesticides residues which could be stored at room temperature for a long time.     

Synthesis of novel fluorene-functionalised nanoporous silica and its luminescence behaviour in acidic media

Fluorene-functionalised nanoporous silica (FL-NH₂-SBA-15) was prepared using the post-synthesis grafting method of SBA-15. The material thus obtained was characterised by means of small- and wide-angle X-ray diffraction, nitrogen adsorption-desorption, Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, and elemental analysis. The results showed that the organised structure is preserved after the post-grafting procedure. Surface area and pore-size decreased by attaching functional groups to the pore surface. In addition, the pore volume was reduced with functionalisation. The amount of fluorene grafted onto the surface of SBA-15 was 0.55 mmol with a yield of approximately 46 %. The emission spectra of FL-NH₂-SBA-15 in acidic media were studied and are discussed in detail. The structural change between FL-NH₂-SBA-15 and the protonated form might be an effective candidate for acid-dependent molecular-sensor models for advanced application in molecular sensors in the future.     

改性ZSM-5-SBA-15及甲苯甲醇烷基化性能研究

通过浸渍法对ZSM-5进行金属M(M为Mg、Ni、Sr)改性,合成法制备了M-ZSM-5-SBA-15复合分子筛,采用XRD、N2吸附-脱附、FT-IR、NH3-TPD和Py-FTIR等技术对样品进行表征,考察了HZSM-5的硅铝比、不同金属对ZSM-5-SBA-15复合分子筛烷基化性能的影响。结果表明,HZSM-5的硅铝比为80时,ZSM-5-SBA-15复合分子筛的烷基化性能较好,Sr的引入钝化了ZSM-5-SBA-15(80)的强B酸中心,降低了B酸与L酸的比值,Sr-ZSM-5-SBA-15(80)的甲苯甲醇烷基化性能明显提高,甲苯转化率为30.15%,对二甲苯选择性为77.41%。     

Extraction of trace amounts of silver on various amino-functionalized nanoporous silicas in real samples

Aminopropyl-functionalized mesoporous silicas, NH₂-MCM-41 and NH₂-SBA-15, as absorbents were utilized for rapid extraction, preconcentration and determination of trace amounts of silver. Flow rates of sample and eluent, pH, eluent solution, type, concentration and the least amount of eluent for desorption of silver ions were optimized; moreover, break through volume and the effect of various cationic interferences on the sorption of silver were evaluated. The extraction efficiency of silver ions was greater than 95% for MCM-41-NH₂ and 85% for SBA-15-NH₂ and the limit of detection (LOD) was less than 4 ng mL^?1 for both functionalized mesoporous silicas. The preconcentration factor was greater than 210 and the relative standard deviation (RSD) was <2%. The adsorption capacity of the mesoporous silicas is higher than 143 mg g^?1 for NH₂-MCM-41 and 137 mg g^?1 for NH₂-SBA-15. Under similar experimental conditions the results for these solid phases were compared with each other. NH₂-SBA-15, in spite of larger pore size diameter and adsorption of silver ions in higher flow rates has lower recovery and a higher RSD compared to MCM-41. This method has been applied to determine silver in photographic emulsions and real samples.     

SBA-15介孔分子筛的乙基化修饰

20世纪90年代初，美孚公司的研究者们用烷基季铵盐阳离子表面活性剂作模板剂，在碱性条件下合成出M41S系列介孔分子筛。近几年，合成出了MCM，HMS，MSU、SBA等硅基分子筛系列。由于介孔材料表面有许多端羟基，可用来固定活性基团，使其在吸附、分离、催化和主客体化学等方面具有广泛的潜在应用价值。对介孔材料孔道进行有机改性的无机-有机复合材料的研究正在兴起，本文采用分步合成法，以乙基三乙氧基硅烷为偶联剂，     

Investigation of СО<Subscript>2</Subscript> adsorption on amine-functionalized silicas and metal-organic polymers

Adsorption properties of amine-functionalized mesoporous silica NH₂-SBA-15, zeolite-like imidazole framework ZIF-8, and amine-functionalized metal-organic polymer NH₂-MIL-53 have been investigated. Non-modified mesoporous adsorbent SBA-15 has a higher sorption capacity for CO₂ than microporous ZIF-8, although microporous sample is characterized by a larger surface area and the values of total pore volume are close. When amine groups are present on the surface of the adsorbents, the chemical adsorption contributes more then the physical one. The adsorption capacity increases with increasing concentration of the functional groups which, in its turn, correlates with adsorbent surface area. Among the studied samples, the best adsorption properties demonstrate amine-functionalized adsorbents, aminefunctionalized mesoporous silica NH₂-SBA-15, and amine-functionalized metal-organic polymer NH₂-MIL-53.