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以混合阳离子-嵌段共聚物表面活性剂为模板合成介孔MCM-48 总被引:2,自引:1,他引:1
利用阳离子和嵌段共聚物混合表面活性剂为模板,在水热条件、碱性介质中成功地合成出MCM-48介孔分子筛。在1TEOS(正硅酸乙酯)∶0.125CTAB(十六烷基三甲基溴化铵)∶nP123(聚氧乙烯-聚氧丙烯-聚氧乙烯三嵌段共聚物)∶0.50NaOH(氢氧化钠)∶61H2O(物质的量的比)体系中,n值在较大范围内(0.000 625~0.018 75)可调。通过粉末X射线衍射(XRD)、N2物理吸附、扫描电镜(SEM)对合成样品进行表征。结果表明:聚氧乙烯-聚氧丙烯-聚氧乙烯三嵌段共聚物(P123)的加入可以更大程度地降低合成MCM-48所需阳离子表面活性剂的用量;合成的MCM-48具有高比表面积、高度有序的孔道结构、较集中的孔径分布和较高的热和水热稳定性。 相似文献
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分别以十六烷基三甲基溴化铵(CTAB)和聚乙氧基-聚丙氧基-聚乙氧基三嵌段共聚物(P123)为模板剂、正硅酸乙酯(TEOS)为硅源,采用水热法合成了有序介孔分子筛MCM-41和SBA-15。选择Eu(DBM)3phen为客体,有序介孔氧化硅MCM-41和SBA-15为载体,分别在氯仿中进行分子组装,制备出具有较强发光性能的介孔复合材料Eu(DBM)3phen/APTES-MCM-41(EAM)和Eu(DBM)3phen/APTES-SBA-15(EAS)。采用XRD、TEM、N2吸附-脱附和荧光光谱等对产物的结构与性能进行了分析。结果表明,Eu(DBM)3phen组装进有序介孔氧化硅的孔道中后,发光纯度提高。而且孔径越小,发光纯度越高。选用较大孔径的SBA-15为载体,在不显著影响发光纯度的同时,可以获得较高的发光强度。 相似文献
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氨水介质中含Ti的MCM-41介孔分子筛的合成 总被引:1,自引:0,他引:1
在氨水介质中采用TiCl3和正硅酸乙酯合成了含Ti量不同的MCM-41介孔分子筛. 该方法可避免使用昂贵的辅助模板剂,也不需要加入醇来调节水解速度,因而合成过程相对简单、易于控制. 采用XRD和N2吸附-脱附等技术对介孔分子筛的结构进行了表征. 结果表明,合成的MCM-41介孔分子筛的六方介孔有序性好,结晶度高. UV-Vis光谱表明,Ti-MCM-41在200~300 nm间出现了四个清晰可辨的吸收峰,说明Ti原子以多种状态存在于介孔分子筛骨架中. 相似文献
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以十六烷基三甲基溴化铵和正硅酸乙酯为原料,合成纯硅MCM-41介孔分子筛。再利用九水硝酸铝为改性剂来嫁接改性纯硅MCM-41介孔分子筛,NH3-TPD结果表明,嫁接后的AlMCM-41产生了中强酸。用改性后不同n(Si)/n(Al)的AlMCM-41催化合成双酚F,在n(苯酚)/n(甲醛)=30、反应时间5 h、反应温度90℃、m(甲醛)/m(AlMCM-41)=7的反应条件下,在一定范围内,双酚F的产率随Al含量增加而增加,但在n(Si)/n(Al)50时,双酚F的产率反而下降,当n(Si)/n(Al)=50时,双酚F的产率最高,为42.28%。 相似文献
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以离子液体为模板剂合成MCM-41的研究——不同扩孔剂对介孔分子筛MCM-41孔径结构的影响 总被引:4,自引:2,他引:2
以离子液体为模板剂, 正硅酸乙酯为硅源, 研究了扩孔剂三甲苯, 癸烷, 以及三甲苯与癸烷1∶1的混合物对介孔分子筛MCM-41结构的影响, 采用XRD以及氮吸附-脱附分析技术对合成的介孔分子筛MCM-41进行了表征.结果表明: 三种扩孔剂中以三甲苯与癸烷1∶1的混合物效果最优, MCM-41的孔径可达到4.5 nm, 并且可以提高介孔分子筛的比表面积与结晶度.扩孔剂的最佳添加量为: 扩孔剂与模板剂之比等于1.0;最佳晶化温度120 ℃. 相似文献
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CMC和CTAB双模板法合成具有稳定结构的MCM-41中孔分子筛 总被引:1,自引:1,他引:0
以羧甲基纤维素和十六烷基三甲基溴化铵为双模板,制备出了具有更高稳定性并且具有高度有序二维六方结构的MCM-41介孔分子筛.透射电镜和X射线衍射结果表明,以双模板制备的MCM-41介孔分子筛具有高度有序的二维六方(p6mm)孔道结构.此外,以双模板制备的MCM-41介孔分子筛焙烧前后的X射线衍射结果表明,在焙烧过程中其晶胞收缩比例为3.1%.与以纯表面活性剂为模版制备的MCM-41介孔分子筛(晶胞收缩比例为9.7%)相比,双模板制备的MCM-41介孔分子筛具有更高的稳定性能. MCM-41介孔分子筛稳定性能的提高可能是由于在硅物种、表面活性剂以及羧甲基纤维素在自组装过程中,羧甲基纤维素表面丰富的羟基与硅物种Si-(OH)x的相互作用促进了Si-(OH)x的缩聚. 相似文献
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合成了外围具有柔性链状基团的2(3),9(10),16(17),23(24)-四-(N,N-二乙胺基乙氧基)Ni-酞菁配合物(2).以正硅酸乙酯为硅源,十六烷基三甲基溴化铵为模板剂,水热法将该Ni-酞菁配合物(2)装载到MCM-41中.利用UV-Vis-NIR,FT-IR,XRD,TEM,FESEM及N2吸附-脱附等温线对制备的样品进行了表征.研究表明制备的样品中Ni-酞菁配合物(2)主要以单体和二聚体的形式存在于MCM-41中.通过不同制备酞菁浓度的装载研究表明,较高制备酞菁浓度有利于制备结晶度及孔道有序性较高的介孔分子筛样品. 相似文献
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XiuMeiTAI HongXiaWANG XiuQiSHI 《中国化学快报》2005,16(6):843-845
Using glycerol, glycol and water as solvent, cetyltrimethylammonium bromide (CTAB) as template, tetraethyl orthosilicate (TEOS) as silica source, ethylenediamine (EDA) as base source, mesoporous molecular sieve MCM-41 has been synthesized at room temperature, characterized by X-ray power diffraction and N2 adsorption. Compared with the samples synthesized by glycol and water, the samples synthesized by glycerol have larger pore diameter and high surface areas. Thus glycerol is an efficient solvent for preparing larger pore mesoporous MCM-41. 相似文献
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This work is focused on the elaboration of methodology for adsorption characterization of porous silicas by using benzene adsorption isotherms measured on good quality MCM-41 materials. Three MCM-41 samples were synthesized by using tetraethyl orthosilicate (TEOS) as silica source and surfactants, octyltrimethylammonium (C8), decyltrimethylammonium (C10) and cetyltrimethylammonium (C16) bromides as templates. A characteristic feature of this synthesis was relatively long hydrothermal treatment (5 days) at 373 K, which gave well ordered samples as evidenced by powder XRD analysis. Benzene adsorption isotherms measured on these MCM-41 samples were used to evaluate such standard quantities as the BET specific surface area, total pore volume, external surface area and the volume of ordered mesopores, and to obtain the statistical film thickness (t-curve) as well as the Kelvin-type relation, which describes the dependence between pore width and condensation pressure for benzene on silica at 298 K. The latter relations were incorporated into the Barrett-Joyner-Halenda algorithm to extend its applicability to calculate the pore size distributions from benzene adsorption data. 相似文献
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Shang-Ru Zhai Jun-Lin Zheng Juan Zou Dong Wu Yu-Han Sun 《Journal of Sol-Gel Science and Technology》2004,30(3):149-155
Structurally ordered MCM-48 silicas were facilely synthesized using the mixtures of cetyltrimethylammonium bromide (CTAB) and p-Octyl polyethylene glycol phenyl ether (OP-10) as co-templates with low molar ratio of CTAB to silica (0.139:1) and low concentration of mixed surfactants (ca. 5%) and within a wide range of OP-10/CTAB ratio (0.08–0.25). For comparison purpose, the cubic material was also prepared with only CTAB as the structure-directing agent under the same preparation conditions. The products obtained by different templating method were thoroughly characterized by XRD, N2 sorption, TEM, TG-DSC and 29Si MAS NMR. Measurement results from these techniques indicated that the introduction of nonionic OP-10 had significant effect on the structural properties of MCM-48 and the mixed surfactants' route allowed an efficient synthesis and a more condensed product compared to the only cationic CTAB templating protocol. Finally, our preliminary explanation for that why cubic MCM-48 materials could be obtained in this system and structural properties were sensitive to the OP-10/CTAB ratios was discussed in detail. 相似文献