合成条件及添加三乙醇胺对水热法合成TS-1分子筛及其性能的影响

以正硅酸乙酯(TEOS)、钛酸丁酯(TBOT)、四丙基氢氧化铵(TPAOH)分别作硅源、钛源及模板剂水热合成了TS-1分子筛.考察了TEOS水解时的水硅比、TEOS水解温度、TPAOH用量及添加三乙醇胺(TEA)对TS-1分子筛合成及其性能的影响.采用XRD、SEM、N2吸附等手段对试样进行表征,同时以环己酮氨肟化反应考察试样的催化活性.结果表明,TEOS水解过程中,n(H2O)/n(S iO2)在20~40的范围内对TS-1的合成及性能影响不大.水解温度较高(60℃)时,加入少量TPAOH(n(TPAOH)/n(S iO2)=0.125)即可得到性能较好的TS-1,而在水解过程中添加适量TEA则能进一步改善TS-1分子筛的性能.在水解温度为60℃、n(S iO2)∶n(TPAOH)∶n(TEA)∶n(H2O)为1∶0.125∶0.065∶20时合成出的TS-1用于环己酮氨肟化反应,环己酮转化率达到90.7%,环己酮肟选择性达到92.4%,催化活性与高TPAOH用量合成的TS-1接近,而TPAOH的用量大大降低.     

钛硅分子筛TS-1合成及应用的研究进展

综述了钛硅分子筛TS－1合成，表征以及催化性能方面的研究进展，着重讨论了合成过程中影响钛进入分析筛骨架的因素，详细介绍了XRD，FT－IR，UV－Vis,XPS,^29SiMAS,NMR等表征技术对TS－1分子筛的分析结果。TS－1双氧水体系的应用研究进展。     

链状结构TS-1分子筛的合成

采用3种合成方法制备链状结构的钛硅分子筛(TS-1),并用X线衍射仪(XRD)、扫描电子显微镜(SEM)、红外光谱仪(FT-IR)和紫外可见分光光度计(UV-VIS)等手段对试样进行表征。研究结果表明:在常规水热合成条件下,TS-1晶体具有沿着[010]面层状堆积生长形成链状结构的趋势。合成温度越高,越容易获得与微波合成相似的较好的链状结构,进入骨架的Ti诱导了分子筛晶粒之间表面羟基的缩合反应,从而导致晶体层状堆积生长,与加热方法无关。     

混合硅源制备钛硅分子筛TS-1及其对噻吩的脱除研究

以工业级硅溶胶与正硅酸乙酯(TEOS)的混合物为硅源,通过一次原位水热晶化成功制备出钛硅分子筛TS-1,并研究了TS-1/H2O2体系对噻吩的脱除效果与再生情况.结果表明,当TEOS占硅源总量的25%时,所得TS-1分子筛样品的晶化率达到100%,晶体粒径约为4～6 μm.该样品与H2O2组成的催化体系在基相浓度为0.03 mol·L-1、催化剂浓度为5 g·L-1、H2O2与基相摩尔比为4∶1的条件下,60℃恒温反应6 h,对噻吩的脱除率达到93.3%,明显优于由单一硅源制备的TS-1样品.经过两次简单加热再生后,该样品对噻吩的6 h脱除率仍可达到75%.     

静态水热法合成B-MWW 分子筛

本文分别以哌啶(PI)和六亚甲基亚胺(HMI)为模板剂用静态水热法合成出B．MWW分子筛。考察了凝胶硅硼比、碱度、碱金属离子、添加晶种、老化时间和晶化时间对晶化产物的影响。发现凝胶SiO2／B2O3比为1．5-6和pH值范围在9．0-10．3下能得到结晶度良好的B-MWW分子筛;碱金属离子存在与否并不影响B-MWW的合成,添加晶种能够提高分子筛的晶化速度,延长老化时间可提高产品纯度。     

钛硅分子筛TS-1的合成改性及其催化功能

钛硅分子筛TS-1由于其优异的催化氧化性能而受到极大关注,TS-1的制备及基础研究是催化领域的一个热点。本文重点综述了近年来钛硅分子筛催化材料的合成、改性及其催化应用的研究进展,包括钛硅分子筛(TS-1)的水热合成方法和同晶取代合成法、改性、成型与负载以及钛硅分子筛催化氧化功能和酸催化功能的研究。     

钛硅分子筛的合成与表征

钛硅分子筛在有机物催化氧化及重金属离子吸附等领域发挥着重要作用。分别从影响因素、合成机理以及催化性能等方面对比了水热合成法、同晶取代法和微波辐射法合成钛硅分子筛的差异,列举了在表征钛硅分子筛中钛原子赋存状态、组成和结构等方面所采用的分析手段,并对钛硅分子筛的基础研究与工业应用进行了评述和展望。     

TS-1钛硅分子筛的制备研究新进展

钛硅分子筛催化剂作为典型的环境友好催化剂体系被广泛应用于低浓度双氧水氧化的绿色有机合成工艺中.详细阐述了钛硅分子筛催化剂的2种制备方法经典的水热合成法及新型的气-固相同晶取代法,并重点指出这2种方法的优劣性.评述了钛硅分子筛催化剂工业化制备中急需解决的问题,指出气-固相同晶取代法二次合成钛硅分子筛由于其制备工序简便,因而具有更加显著的成本优势和广阔的工业应用前景.     

TS-1分子筛在环己酮氨肟化反应中的应用

叙述了TS-1分子筛在环己酮氨肟化反应中的应用研究进展．阐述了国内外对环己酮氨肟化催化剂的研究概况及在工业化应用中所存在的问题,指出了TS-1分子筛在环己酮氨肟化反应中的应用研究主要集中在催化剂合成技术、分离和回收以及降低生产成本等方面。     

ZSM-35分子筛合成及影响因素研究

在氢氧化钠和氢氧化钾溶液中,以环己胺和硅溶胶为原料,通过K+与Na+对丝光沸石生成的抑制,成功合成了纯度很高的ZSM-35分子筛相,并利用X-光衍射分析仪对不同条件下形成的样品XRD光谱图,对影响ZSM-35分子筛生成的外界因素进行了分析,结果显示:ZSM-35分子筛形成的最佳碱度是3.3~3.5,n(SiO2)∶n(Al2O3)=20,晶化时间为40h时,ZSM-35分子筛的特征衍射峰强度很高,可以合成高纯度度晶化的ZSM-35分子筛样品,为ZSM-35分子筛的开发利用提供新的思路。     

Synthesis of Hierarchical TS-1 Zeolite from Silanized Seeds

Hierarchical TS-1 zeolites with a bimodal pore architecture, consisting of the typical MFI micropores and an additional mesoporosity, have been synthesized by grafting an organosilane compound to the zeolitic seeds previously prepared from two different raw materials: a liquid gel and an amorphous SiO₂–TiO₂ xerogel. These hierarchical TS-1 zeolites show an excellent catalytic behavior in olefin epoxidation reactions employing organic hydroperoxides as oxidants due to the presence of the secondary mesoporosity, which makes possible the access and interaction of bulky molecules with the Ti active sites.     

Hydrothermal conversion of ETS-10 to TS-1

Titanium silicalite-1 (TS-1) was hydrothermally using ETS-10 as a dual source of silicon and titanium after acid and calcination treatment. The conversion process was monitored by XRD, SEM, UV–Vis and FT-IR spectra. Catalytic performance of the prepared TS-1 catalyst was tested by 1-hexene epoxidation using H₂O₂ as oxidant, which established that the TS-1 converted from ETS-10 has essentially identical physicochemical properties to those of conventional TS-1 prepared using pure alkoxide precursors.     

NMR Study on the Acidity of TS-1 Zeolite

The acidic properties of TS-1 and Silicalite-1 zeolites have been investigated by the solid-state MAS NMR technique capable of in situ sample pretreatment. As shown by a combination of the ³¹P MAS NMR and ¹H MAS NMR techniques with trimethylphosphine, not only Brønsted acid sites but also Lewis acid sites exist in the TS-1 zeolites. Moreover, TS-1 zeolite is more acidic compared with Silicalite-1. The ¹H, ²⁹Si MAS NMR spectra and the resonance related to Brønsted acid species in the ³¹P MAS NMR spectra demonstrate clearly that the presence of titanium in the framework results in the formation of a new hydroxy group, titanols, which is more acidic than silanols of Silicalite-1. The ³¹P MAS NMR measurements also illustrate convincingly the existence of at least two different Lewis acid species on the TS-1 zeolites. The conversion of propylene oxide into methoxypropanol catalyzed by TS-1 or Silicalite-1 zeolite in methanol solution as a test reaction has also been described. With the increase of titanium in zeolite, TS-1 appears to have a higher activity during the reaction of propylene oxide to methoxypropanol.     

Epoxidation of Linear Olefins over Stacked TS-1 Zeolite Catalysts

Stacked TS-1 [NSTS-1(MW)] has been prepared by microwave synthesis and applied to the epoxidation of linear olefins with H₂O₂ under mild conditions, and the epoxidation activities were compared with the non-stacked TS-1 and the conventional TS-1, which were also synthesized by microwave and by typical hydrothermal method, respectively. Stacking of TS-1 crystals was accomplished by using microwave which facilitated the dehydration of hydroxyl groups on the external surface of crystallites through the selective absorption of microwave onto Ti species. The stacked crystallites seemed to allow the running pore structure in the b-axis orientation through the crystallites in the stacked morphology. Besides this unique pore structure, the stacked TS-1 showed peculiar features like higher hydrophobicity and enhanced catalytic property than typical TS-1. Moreover, the NSTS-1(MW) showed the highest activity in the epoxidation of linear olefins among three catalysts, and also coincided with the differences in the adsorption of linear aliphatics due to strong interaction with the straight channel in the stacked morphology, which gave larger Henry’s constants, obtained by the tracer chromatographic analysis, as the increase in the carbon chain length.     

钛硅分子筛催化制备N-氧化吡啶工艺研究

以钛硅分子筛为催化剂,以吡啶、双氧水为原料催化氧化合成 N-氧化吡啶。实验考察催化剂用量、吡啶与双氧水配比、反应温度、反应时间等对反应结果的影响。确定了较佳的工艺操作条件,即在TS-1分子筛催化剂作用下,催化剂与吡啶的质量比为1∶10,反应温度为80℃,吡啶与双氧水的摩尔比为1∶2,双氧水分多次滴加,反应时间为6 h。在此操作条件下,吡啶氧化转化率可达92%以上,N-氧化吡啶选择性可达97%。     

预处理条件对水热合成沸石的影响

预处理条件对水热合成沸石影响较大,尤其对于合成时间较短的微波法更为重要。着重讨论预处理中时间、温度、碱度对硅铝的溶解效果的影响。     

氧化铝陶瓷管负载TS-1沸石膜的制备及表征

利用二次晶种生长法在α-Al2O3陶瓷管上制备TS-1沸石膜,详细研究了晶化时间对TS-1沸石膜表面形貌、沸石层厚度、沸石生长速率及气体渗透性能的影响.通过扫描电子显微镜(SEM),X-射线衍射仪(XRD),红外光谱(FT-IR)、紫外光谱(UV-Vis)及N2渗透测试对TS-1沸石膜进行了全面表征.研究结果表明:随着晶化时间的延长,TS-1膜层表面沸石粒子互生性增强,且膜层厚度也随之增加.然而,随着沸石层厚度的增加,其气体传输性能下降.当晶化时间为48 h,沸石生长速率最快,为0.087 μm/h,此时TS-1沸石膜厚度为4μm,表面平整,无明显缺陷.     

粉煤灰水热法合成沸石及其表征

本文考察了4M氢氧化钠水溶液和121℃条件下水热反应时间对粉煤灰合成产物的影响,用粉末X-射线衍射(PXRD)、扫描电镜(SEM)、差式扫描量热(DSC)以及热重(TG)等手段对产物进行了分析表征.Jade 6.0软件分析表明,粉煤灰水热反应合成了羟基方钠石,其晶胞参数为a=b=c=0.906 nm.随着水热时间的延长,合成羟基方钠石的结晶度和含量增加.合成产物呈表面粗糙的球状,粒度随水热时间延长而增大.热分析结果表明合成羟基方钠石中含有结晶水,其分子式为Na8Al6Si6O24 (OH)2·2H2O.粉煤灰400 min水热合成产物中的二水羟基方钠石纯度约为65.32％.