模板剂在沸石合成过程中的作用机理研究

通过分子模拟途径,对有机模板剂的分子与沸石骨架间非成键互作用的能学分析,论证不同工的双季铵盐「（ＣＨ３）３＋／Ｎ（ＣＨ２）ｎＮ＋／ｎ（ＣＨ３）３」２Ｂｒ在四种沸石（ＺＳＭ－５０、ＺＳＭ－１２、ＮＵ－８７和ＺＳＭ－２３）合成中所超的模板作用。主为这种模板作用可用非成键互作用能定量表达;在一定程度上解释了Ｍ等人固定胶凝条件、实验考察以双季铵盐系列作为模板剂的合成结果。     

导向剂法合成U沸石的光谱研究

采用导向剂法合成了β沸石。ＸＲＤ光谱测定表明,导向剂的成活以及β沸石的形成被局限于相对较窄的相区范围内。β沸石的２９Ｓｉ和２７Ａｌ－ＮＭＲ 光谱表征进一步说明β沸石骨架硅铝四面体的排列较为规整,其中Ｎａ＋ 离子起着平衡沸石骨架负电荷的作用。     

导向剂法合成β沸石的光谱研究

采用导向剂法合成了β沸石。ＸＲＤ光谱测定表明,导向剂的成活以及β沸石的形成被局限于相对较窄的相区范围内。β沸石的＾２９Ｓｉ和＾２７Ａｌ－ＮＭＲ光谱表征进一步说明β沸石骨架硅铝四面体的排列较为规整,其中Ｎａ＾＋离子起着平衡沸石骨架负电荷的作用。     

模板剂四乙基氢氧化铵的用量对合成的β沸石结构及脱胺的影响

研究四乙基氢氧化铵（TEA-OH）模板剂用量对合成的β沸石的结构及脱胺行为的影响。合成β沸石的模板剂的较佳用量(TEA+/Al)为2.10～1.68,合成的β沸石的相对结晶度均大于84%;β沸石中的铝含量(Al/Al+Si)及骨架铝含量(TdAl/TdAl+OhAl)随晶化混合液的TEA+/Al而变,存在最佳TEA+/Al点为1.9,此时合成的β沸石非骨架铝量最少,结构硅铝比最高;含TEA的β沸石脱胺过程为Hofmann降解反应,TGA测定的失重量、DSC测定的吸热量与β沸石中TEA含量密切相关.     

丝光沸石的Monte Carla研究：Ⅱ.脱铝丝光沸石的骨架硅,铝分布

以马尔可夫链近似模拟线光沸石脱铝过程，用ＭｏｎｔｅＣａｒｌｏ方法计算脱铝丝光沸石中骨架Ｓｉ－Ａｌ近邻分布｛Ｓｉ（ｎ－Ａｌ）；ｎ＝０－４｝和Ａｌ－Ａｌ次部分布｛Ａｌ（ｍ－Ａｌ）；ｍ＝０－３｝随铝浓度的演化。为使Ｓｉ－Ａｌ近邻分布与对脱铝丝光沸石样品的＾２＾９ＳｉＭＡＳＮＭＲ观测相符，而得到丝光沸石弱酸铝易于解脱的结论，这个结构与八面沸石弱酸铝易于解脱相反。根据计算丝光沸石脱铝的开始阶段，强酸中心...     

有机锡化合物的光电子能谱（XPS）和质谱（MS）研究Ⅱ

本文报道了７种新合成的（Ｚ）－１－（２－（三芳基锡）乙烯基）－１－环庚醇有机锡化合物的ＸＰＳ和ＭＳ结果，通过ＸＰＳ讨论了化合物中不同取代基的存在，对锡内层电子的影响及取在对Ｏｈ结合能化学位移的作用，结果表明，卤素在这里起着得要的作用，通过ＭＳ和ＸＰＳ讨论了不同取代基对Ｏ→Ｓｎ键的影响。     

不同模板剂合成SAPO-34分子筛的表征与热分解过程研究

采用XRD、SEM、FT IR、TG DTA等表征手段 ,对分别以正磷酸、拟薄水铝石和硅溶胶为磷源、铝源和硅源 ,用五种模板剂合成的SAPO 34分子筛进行了表征 .不同模板剂合成的SAPO 34分子筛在晶粒粒度分布上有相当大的差异 .通过TEAOH Et3 N或者TEAOH Morpholine复合模板剂法可以有效地调节晶粒粒度 .不同模板剂合成的SAPO 34分子筛的红外骨架振动相似 ;而模板剂分子与分子筛骨架的作用方式有区别 .模板剂种类对SAPO 34分子筛骨架热稳定性没有影响 ,但对其热分解的行为有影响     

抑制β沸石骨架脱铝的焙烧研究

研究了因焙烧过程升温速率对β沸石模板剂的热分解过程的影响 ,不同升温速率下Naβ沸石焙烧的尾气组成 ;还测定了Naβ沸石的TG -DTG谱 ,40 0℃下Naβ沸石的FTIR谱图 ,以及在不同温度下焙烧 4h后的XRD谱图及2 9Si、2 7Al的NMR结果 .根据这些结果 ,提出了分段焙烧脱胺方法 ,使有机胺在 2 6 0～ 42 0℃间的两个恒温段充分发生Hofmann降解反应 ,从而使分解产生的乙烯和水蒸气能够随空气流自然排出焙烧体系 ,可使焙烧过程中产生的热能得到分阶段逐步地释放 ,同时可避免高温下沸石骨架水热脱铝的负作用 ,得到骨架脱铝少、结晶度高的脱胺 β沸石 .     

菱钾沸石中铝在不等价四面体位上分布的^29SiMASNMR谱研究

根据菱钾沸石＾２９ＳｉＭＡＳＮＭＲ实验讨论了骨架Ｓｉ／Ａｌ比（Ｒ）和Ａｌ在两种不等价四面体位分配比率（ｒ）二者之间必须满足的关系，对于合成原粉，Ａｌ择优占据ＴＢ位；用（ＮＨ４）２ＳｉＦ６同晶取代脱铝，ＴＢ位上的Ａｌ择优解脱。     

MASNMR研究钯添加剂对SAPO－5分子筛的影响

通过在ＳＡＰＯ－５分子筛的前身体中加入不同含量不同形式的钯盐方式，直接合成出了分子筛上担载贵金属的双功能催化剂，Ｘ光衍射（ＸＲＤ）结果表明把的加入并不影响ＳＡＰＯ－５分子筛的生成，但降低了分子筛结晶度。当把以碱性介质加入反应物时，使产物中有少量ＳＡＰＯ－３４伴生，由ＭＡＳＮＭＲ实验结果可见，反应物中把的加入抑制了硅进入分子筛骨架，使骨架铝配位环境更加对称，并使三乙胺模板分解，改变了其在分子筛中的存在状态。从而导致分子筛结晶度的降低．     

Fe-ZSM-5杂原子分子筛的合成与表征

采用静态水热法分别以正丁胺、四丙基溴化铵为模板剂合成ZSM-5分子筛及Fe-ZSM-5杂原子分子筛；利用XRD与FT-IR对其结构进行表征；考察了Mo改性后分子筛催化剂上甲烷脱氢芳构化的反应性能。结果表明，Fe部分进入了分子筛的骨架，导致分子筛的结晶度及表面酸强度的下降，使Mo／Fe-ZSM-5催化剂的反应性能较Mo／HZSM-5显著下降。     

Facile synthesis of mesoporous ZSM-5 aided by sonication and its application for VOCs capture

Application of ultrasound power to the mother liquor is popular pretreatment for zeolite synthesis which offers a simple way of accelerating crystallization process and finetuning the properties of nanocrystalline zeolites. In this work, sonication-aided synthesis of mesoporous ZSM-5 at low temperature and ambient pressure was systematically studied, in an attempt to reach efficient and benign synthesis of zeolites with hierarchical pore structure, which has wide applications as catalysts and sorbents. The effects of sonication duration, power density, sonication temperature and seeding on the crystallization of ZSM-5 were investigated. The obtained samples were characterized by XRD, SEM, BET and VOCs capture. High quality mesoporous ZSM-5 can be obtained by a facile 5 d synthesis at 363 K, much faster than conventional hydrothermal synthesis. The reduced synthesis time was mainly attributed to the enhanced crystallization kinetics caused by the fragmentation of seeds and nuclei, while sonication radiation had little impact on the nucleation process. Compared with control sample, mesoporous ZSM-5 prepared by sonochemical method had higher surface area and mesoporosity which demonstrated improved adsorption performance for the capture of isopropanol.     

Comparative study on diameter distribution of single-walled carbon nanotubes using growth templates with different pore sizes: Zeolite-L,ZSM-5, and MCM-41

We report a comparative study on diameter distribution of single-walled carbon nanotubes (SWNTs) grown using nanoporous templates having different pore sizes, namely, zeolite-L, ZSM-5, and MCM-41. The change in the tube diameter based on catalytic film thickness and growth temperature was systematically investigated. We prepared very thin Fe catalyst films with nominal thicknesses of 0.5, 0.7, 1, and 2 Å, and the growth temperature was varied from 850 to 925 °C. We found that the SWNT mean diameter and size distribution width decreased with decreasing catalyst film thickness, growth temperature, and pore sizes of the templates. In addition, all SWNTs grown from the nanoporous templates have narrower diameter distribution compared to the SWNTs grown from SiO₂ planar surface. The obtained results are straightforward and suggest that the template growth has potential for SWNT growth with very narrow diameter distribution.     

Key factor affecting the structural and textural properties of ZSM-5/MCM-41 composite

ZSM-5/MCM-41 micro/mesoporous composite materials were synthesized by the hydrothermal technique with alkali-treated ZSM-5 zeolite as source of silica and aluminum and characterized by various physico-chemical techniques such as X-ray diffraction (XRD), nitrogen sorption at 77 K, transmission electronic microscopy (TEM), FTIR spectroscopy and NH₃ temperature programmed desorption (TPD) techniques. The effect of concentration of CTAB in the synthesis of these solids has been investigated, the mesopore volume, surface area and surface acidity decrease with increasing the concentration of CTAB. Increasing the CTAB concentration causes the recrystallization of zeolite ZSM-5 and it disadvantage the formation of mesoporous materials MCM-41. The catalytic activity of ZSM-5/MCM-41 materials has been evaluated in the Friedel–Crafts acylation of anisole with benzoyl chloride as alkylating agent. The results revealed the reaction to be influenced by surface area, pore volume and surface acidity.     

Methane non-oxidative aromatization on Mo/ZSM-5: Effect of adding triethoxyphenylsilanes into the synthesis system of ZSM-5

A series of ZSM-5 zeolites were synthesized by adding triethoxyphenylsilane (PTEOS) into the initial sol of the synthesis system. The samples were studied by XRD, SEM, N₂ adsorption-desorption and acid assessment of d₃-acetonitrile adsorption. Characterization results showed that the crystal size of the ZSM-5 zeolites could be adjusted in a certain range by introducing different contents of PTEOS. Besides, the resultant materials possess hierarchical porosity in addition to those micropores generated by the MFI channels. Moreover, supported Mo/ZSM-5 catalysts were prepared, and their catalytic performances were investigated in the methane non-oxidative aromatization. It was found that the Mo/ZSM-5 catalyst, bearing suitable crystal size and mesoporous characteristic showed relatively high shape-selectivity to benzene and high stability for the reaction of methane aromatization.     

改性ZSM-5分子筛催化合成乙酸戊酯

以ZSM-5为原料,采用浸渍法将其交换成HZSM-5,以HZSM-5为催化剂,对以冰乙酸和正戊醇为原料合成乙酸戊酯的反应条件进行了研究。研究表明,以1.0m ol/L硫酸浸渍后的ZSM-5催化活性最高,当醇酸摩尔比为1.1∶1,催化剂用量为0.4g,反应时间为90m in,反应温度为125—135℃,酯化率可达82.5%。     

Ultrasound-assisted rapid hydrothermal design of efficient nanostructured MFI-Type aluminosilicate catalyst for methanol to propylene reaction

The influence of ultrasound-assisted rapid hydrothermal synthesis of aluminosilicate ZSM-5 catalysts was examined in this work. A series of MFI-type nanostructured materials with sonochemical approach and conventional heating were synthesized and evaluated for conversion of methanol to propylene reaction. The prepared samples were tested by characterization analyses such as XRD, FESEM, BET-BJH, FTIR, TPD-NH₃ and TG/DTG. The obtained results confirmed that ultrasound treatment enhanced the nucleation process and crystal growth for ZSM-5 sample synthesized at moderate temperature of 250 °C. Therefore, it was found the formation of pure MFI zeolite with high crystallinity and improved textural, structural and acidic properties for ZSM-5(UH-250) sample compared with the other zeolites. This observation was attributed to the relationship between the perfect crystallization mechanism and catalytic properties, which led to producing an efficient MFI zeolite toward the optimal catalytic performance. In this manner, the methanol conversion and products selectivity of prepared materials were carried out in MTP reaction at 460 °C and atmospheric pressure. The ZSM-5(UH-250) zeolite with slower deactivation regime exhibited the constant level of methanol conversion (84%) and high propylene selectivity (78%) after 2100 min time on stream. Moreover, the synthesis pathway for MFI zeolite at moderate temperature and also deactivation mechanism of improved sample were proposed.     

表面润湿法合成β沸石体系中晶种作用的研究

系统研究了表面润湿法合成β沸石的体系中,干晶种、润湿态晶种、异晶晶种(Y沸石、ZSM 5沸石)以及碱处理β沸石晶种在此晶化体系中的作用.采用β沸石产品及异晶作晶种时,可使产品的相对结晶度稍有提高,但对沸石微晶核的结构导向作用不明显.经浓碱液处理20min后的β沸石产品(碱处理晶种)作晶种引入晶化体系后,可以显著提高产品的相对结晶度,降低模板剂的用量,缩短晶化诱导期,成为表面润湿法合成β沸石体系的有效晶种形式.     

Synthesis of Pt modified ZSM-5 and beta zeolite catalysts: influence of ultrasonic irradiation and preparation methods on physico-chemical and catalytic properties in pentane isomerization

Influence of preparation methods and ultrasound irradiation on physico-chemical and catalytic properties was investigated by synthesizing Pt-ZSM-5 and Pt-Beta catalysts by in-situ and impregnation methods and applying ultrasound irradiation to synthesis gel mixture of ZSM-5 and Beta zeolites. It was concluded from the X-ray powder diffraction patterns of Pt-ZSM-5 and Pt-Beta zeolite catalysts that introduction of Pt by in-situ method and ultrasound irradiation did not influence the structures of ZSM-5 and Beta zeolites. Morphology of ZSM-5 and Beta zeolites were investigated by scanning electron microscopy. SEM micrographs showed that the Pt-ZSM-5-IS-US catalyst synthesized by in-situ method with ultrasound irradiation resulted in smaller crystals of ZSM-5 than Pt-ZSM-5-IS catalyst prepared without ultrasound irradiation. Furthermore SEM micrographs of Pt-Beta-11-IS-US zeolite synthesized using ultrasound irradiation showed much smaller crystals than Pt-Beta-11-IM indicating that ultrasound irradiation had a significant effect on the morphology of Beta zeolite. Conversion of n-pentane and selectivity to iso-pentane over the Pt-ZSM-5-IS-US zeolite catalysts prepared by ultrasound irradiation during in-situ introduction of platinum was higher than the catalysts prepared without the ultrasound irradiation. Furthermore ultrasound irradiated and in-situ synthesized Pt-Beta-11-IS-US catalyst also showed higher selectivity to iso-pentane than Pt-H-Beta-11-IM prepared by impregnation method.