有机基团改性介孔硅基材料的研究进展

介绍了有机基团改性介孔硅基材料的种类及研究现状。经不同有机基团改性后,材料的活性位点增多,亲疏水性能改变以及水热稳定性增加,使其在吸附、医疗以及建筑领域有着广泛的应用。详细介绍了其在吸附重金属离子,染料分子,气体分子以及阴离子中的应用,同时介绍了经有机基团改性后材料接触角改变在古建筑保护和油水分离方面的应用。并对目前研究中存在的问题进行总结并对该杂化材料的发展趋势进行了展望。     

有机基团改性介孔硅基材料的研究进展

介绍了有机基团改性介孔硅基材料的种类及研究现状。经不同有机基团改性后,材料的活性位点增多,亲疏水性能改变以及水热稳定性增加,使其在吸附、医疗以及建筑领域有着广泛的应用。详细介绍了其在吸附重金属离子,染料分子,气体分子以及阴离子中的应用,同时介绍了经有机基团改性后材料接触角改变在古建筑保护和油水分离方面的应用。并对目前研究中存在的问题进行总结并对该杂化材料的发展趋势进行了展望。     

Asymmetric catalysis by chiral salen complexes immobilized on mesoporous materials having modified pore channel system by dimethylcarbonate

The mesoporous materials having bimodal pore structure were synthesized by treatment of dimethylcarbonate (DMC) in the presence of metal salts as a catalyst. The pore system was characterized by BET, TEM analysis and by comparing the catalytic activity under the same conditions. The chiral (salen) Co-MX₃ immobilized on SBA-15 and MCM-48 which were partially desilylated by DMC showed higher activity for the enantioselective kinetic resolution of terminal epoxides with H₂O and phenols, relative to original SBA-15 and MCM-48 having regular pore channels. The heterogeneous catalysts can offer practical advantages of the facile separation from reactants and products, as well as recovery and reuse.     

介孔材料合成研究进展

介孔材料具有比表面积大、孔径结构均一和可调等优良性能,在催化、吸附、分离、传感器以及光、电、磁等领域具有潜在的应用价值。综述了介孔材料的研究进展,介绍了介孔材料的分类、合成方法、合成机理及其应用。阐述了液晶模板、电荷匹配、棒状自组装、层状折皱模型和协同作用等介孔材料的合成机理,对介孔材料进行了展望。     

Friedel Crafts acylation of aromatic compounds over arenesulfonic containing mesostructured SBA-15 materials

Arenesulfonic modified mesostructured SBA-15 is shown as an active catalyst for acylation of aromatic compounds using acetic anhydride as acylating agent. Arenesulfonic acid-centers anchored on the pore surface of a mesostructured SBA-15 material show a greater activity (normalised on the concentration of sulfonic groups) as compared to other homogeneous and heterogeneous sulfonated catalysts and even in solventless conditions. This high activity is accompanied with a remarkable thermal stability of the acid centers, without leaching of sulfur species during the reaction. Moreover, an increase of the amount of arenesulfonic centres does not modify the activity of the material per acid center. Thus, this work introduces a new application of these sulfonated mesostructured materials, not described in literature up to now.     

Oxygen sorptivity of mesoporous aluminosilicate modified by Co-salen complex

Mesoporous aluminosilicate, FSM-16 (Al-FSM-16(n)), was functionalized by Co-salen modification. The Si/Al ratio, n, was varied from 12.8 to 60.0, and inclusion of Co-salen (N,N^′-bis(salicylidene)ethylenediaminocobalt(II)) was carried out by a novel preparative method comprising Co²⁺ ion exchange in a nonaqueous solution of cobalt(II) acetate and chelation with salen-H₂ (N,N^′-bis(salicylidene)ethylenediamine). Prominent O₂ sorptivity was imparted to this mesoporous material and the amount of O₂ sorbed on Co-salen-Al-FSM-16(60.0) was 0.275 mmol g⁻¹ at 298 K, significantly larger than that on Al-FSM-16(60.0) itself (0.085 mmol g⁻¹). The O₂ sorption on Co-salen-Al-FSM-16(60.0) remarkably proceeded under a pressure around 20 kPa at 298 K, which was similar to powdery, free Co-salen. The maximum O₂/Co-salen ratio for Co-salen included in mesopores was seven times as large as that for neat Co-salen. The pore structure of Al-FSM-16(n) with a high n value was retained through the modification as evidenced by XRD, TEM and N₂ adsorption measurements, but that of Al-FSM-16(12.8) was partly collapsed.     

Ethylene polymerization catalyzed by metallocene supported on mesoporous materials

Summary  In this work, different mesoporous materials were employed for the preparation of supported metallocene catalysts to be evaluated in ethylene polymerization and their performance was related to the chemistry of the materials surface used as support. The supports employed were MCM-41, SBA-15 and mesoporous TiO₂. The performance of the prepared catalysts was compared with the homogeneous catalyst precursor system. Those mesoporous materials, as well as the prepared metallocene catalysts, were analyzed by infrared absorption spectrometry (FTIR). Polymers were also characterized by FTIR, for the determination of the number-average molecular weight, and by differential scanning calorimetry (DSC) to determine thermal characteristics of the produced polyethylene. Among the studied metallocene supported catalysts, the one based on the mesoporous support SBA-15 achieved the highest activities, almost as high as that observed for the homogeneous system.     

New mesoporous carbon materials synthesized by a templating procedure

The new porous carbon materials were obtained by templating procedure using mesoporous silica (SBA-15) as template. The ordered mesoporous silica materials were synthesized by using Pluronic P123 (non-ionic triblock copolymer, EO₂₀PO₇₀O₂₀). SBA-15/cryogel carbon composites were obtained by sol–gel polycondenzation of resorcinol and formaldehyde in the presence of different amount of SBA-15. The polycondenzation was followed by freeze drying and subsequent pyrolysis. One set of SBA-15/sucrose carbon composites was prepared by using sucrose as carbon source. The silica template was eliminated by dissolving in hydrofluoric acid (HF) to recover the carbon material. The obtained carbon replicas were characterized by nitrogen adsorption–desorption measurements, X-ray diffraction and scanning electron microscopy (SEM). It was revealed that the samples have high specific surface (533–771 m² g^?1), developed meso- and micro-porosity and amorphous structure. Porous structure of carbon replicas was found to be a function of the carbon source, properties of SBA-15 and silica/carbon ratio. Room temperature adsorption of nitrogen and adsorption of phenol from aqueous solutions were investigated.     

磺酸型介孔材料催化合成甲基葡萄糖苷

以甲醇和葡萄糖为原料,采用一步合成法合成甲基葡萄糖苷。以磺酸型介孔材料作为催化剂,借助扫描电子显微镜、高分辨率透射电子显微镜、低温氮气吸附/脱附、热重分析等方法研究了材料的结构和性能。实验结果表明,催化剂用量为0.6g,醇糖摩尔比为28∶1,反应温度为115℃,反应时间为2 h为最佳反应条件,此条件下合成产物的收率可达95.67%。同时使用Fourier红外光谱仪对产物进行了表征。     

金属改性的介孔硅材料FSM-16催化苯酚与H_2O_2合成苯二酚

研究了金属改性的介孔硅材料FSM-16在该反应中的催化性能。其中Fe和Cu改性的FSM-16表现出比较好的性能。在Fe-FSM-16的作用下,苯酚的转化率达到27.8%,对苯二酚和邻苯二酚选择性达到96.4%(邻/对=1.8)。FT-IR和XRD表征证明铜离子进入了FSM-16的骨架,并形成了Si—O—Cu键。     

Controlling the textural parameters of mesoporous carbon materials

The mesoporous carbon materials prepared by inorganic templating technique using mesoporous silica, SBA-15 as a template and sucrose as a carbon source, have been systematically investigated as a function of sucrose to mesoporous silica composition, with a special focus on controlling the mesoporous structure, surface morphology and the textural parameters such as specific surface area, specific pore volume and pore size distribution. All the materials have been unambiguously characterized by XRD, N₂ adsorption–desorption isotherms, high-resolution transmission electron microscopy, high-resolution field emission scanning electron microscopy, and Raman spectroscopy. It has been found that the porous structure, morphology and the textural parameters of the mesoporous carbons materials, CMK-3-x where x represent the sucrose to silica weight ratio, can be easily controlled by the simple adjustment of concentration of sucrose molecules. It has also been found that the specific surface area of the mesoporous carbon materials systematically increases with decreasing the sucrose to silica weight ratio. Moreover, the specific pore volume of the materials increases from 0.57 to 1.31 cm³/g with decreasing the sucrose to silica weight ratio from 5 to 1.25 and then decreases to 1.23 cm³/g for CMK-3-0.8. HRTEM and HR-FESEM also show a highly ordered pore structure and better surface morphology for CMK-3-1.25 as compared to other materials prepared in this study. Thus, it can be concluded that the sucrose to silica weight ratio of 1.25 is the best condition to prepare well ordered mesoporous carbon materials with good textural parameters, pore structure and narrow pore size distribution.     

体积排阻色谱法测定介孔材料的孔结构

分别合成了球形的苯基桥键和乙烷桥键两种新型杂化介孔材料.选用已知平均相对分子质量且具有窄相对分子质量分布的葡聚糖为探针溶质,采用动态光散射法测定了粒径,与经验公式计算结果接近.通过体积排阻法对两种材料的孔隙率和孔径分布进行测定并与氮气吸附法结果进行比较,实现介孔材料孔结构快速测定.结果表明,体积排阻色谱法测定苯基桥键和...     

Direct synthesis of highly ordered Co-SBA-15 mesoporous materials by the pH-adjusting approach

Cobalt-substituted SBA-15 (Co-SBA-15) mesoporous materials were directly synthesized under mild conditions (pH > 2.0) by a “pH-adjusting” method using sodium hydroxide. Characterization results, such as powder X-ray diffraction (XRD), N₂ physisorption and high-resolution transmission electron microscopy (HRTEM), showed that the resultant materials exhibit highly ordered hexagonal mesoporous structures, which was strongly correlated to the pH in the synthesis solution. The Co-SBA-15 sample obtained at pH of 3.0 gave the best structure. Solid state magic-angle-spinning nuclear magnetic resonance (MAS NMR) results indicated less condensation under higher pH. In addition, the pH also strongly affected the incorporation of cobalt cations in the silica framework. Diffuse reflectance UV–vis absorption spectra of calcined Co-SBA-15 samples and hydrogen temperature programmed reduction (H₂-TPR) demonstrated that the cobalt ions in the silica framework locate at tetrahedrally coordinated sites. The effect of pH and sodium (NaOH) addition on improving the cobalt ion incorporation and the mesostructure of Co-SBA-15 materials were also discussed.     

软模板法合成有序介孔材料的研究进展

有序介孔材料具有高度有序的孔道结构,较高的比表面积和较多活性位,已经广泛应用于气体吸附、催化剂和功能材料等领域。本文系统评述了软模板法制备有序介孔材料的合成路线及其组装机理,并对课题组采用软模板法组装介孔氧化钛粒子的机理进行了分析。     

酚醛树脂改性氨基模塑料

用酚醛树脂对氨基模塑料进行改性,使成型性得到改善,制品韧性增强。制备了酚醛树脂改性氨基模塑料,并讨论其加工成型特性和韧性的提高。     

无机介孔材料的合成研究新进展

综述了无机介孔材料的制备方法,包括软模板法和硬模板法,并对硬模板法包含的液相浸渍法、化学气相沉积法(CVD)、固相研磨法、超声波辅助法进行了详细阐述,展望了硬模板法合成介孔材料的前景。     

含锆介孔材料的研究进展

介绍了目前国内外对介孔氧化锆和含锆介孔二氧化硅材料的研究状况,包括合成介孔氧化锆的2种主要体系水热体系和非水体系,以及在介孔二氧化硅中引入锆的主要方法直接合成法和溶液浸渍法,这2类材料在化学、光学、电子学、电磁学、材料学、环境学等诸多领域具有巨大的潜在应用价值.     

介孔材料的制备与应用进展

综述了模板法、水热法、溶胶-凝胶法、溶剂热法、超声化学法及反胶束法等制备介孔材料的方法,其中模板法介绍了阳离子表面活性剂、阴离子表面活性剂、非离子表面活性剂、混合表面活性剂以及非表面活性剂等作为模板剂在介孔材料制备中的应用.评述了介孔材料的几种典型形貌,并对介孔材料在催化、吸附分离、传感器电极材料的制备以及酶的固定与分离等领域的应用进行了简要介绍.     

双介孔材料的合成与应用研究进展

双介孔材料是一种同时具有小介孔和大介孔的新型多级孔材料,在吸附和催化方面具有广阔的应用前景,因此也引起许多研究者的关注。本文较全面地总结了双介孔材料的合成方法,探讨了双介孔材料作为吸附剂和催化剂载体的应用研究状况,并对今后的发展方向进行了展望:如何有效地控制两种介孔的孔结构和孔的空间分布、结构和物化性能的表征以及如何改性以扩大其应用领域尚需进一步的研究。