无机原料体系合成TS-1影响因素的研究

以廉价的硅溶胶和三氯化钛分别作为硅源和钛源,四丙基溴化铵(TPABr)为模板剂,二乙胺、正丁胺、氨水等作为碱源,在无机体系中合成了TS-1分子筛。采用XRD,IR,UV-vis,SEM,元素分析和N2吸附/脱附等对合成的分子筛进行了表征。详细考察了碱源、硅钛比N2保护、晶种、模板剂用量、硅源及晶化时间等因素对分子筛合成的影响。结果表明,以无机原料合成的TS-1与用传统有机原料合成的TS-1具有同样的特征。碱度的控制是合成的关键,配胶时需N2保护,加入晶种对合成有明显的导向作用,模板剂最低用量有一临界值,硅溶胶作硅源合成的TS-1晶粒比较大。     

无机钛硅原料合成TS-1催化氯丙烯环氧化反应

采用无机钛硅原料体系合成出了TS-1分子筛,并对TS-1分子筛催化氯丙烯环氧化反应进行了研究.在以甲醇为溶剂的体系中考察了反应时间、反应温度、催化剂用量、氯丙烯与双氧水的摩尔比对反应的影响,得到了无机钛硅原料体系合成的TS-1催化氯丙烯环氧化反应的最优条件:反应时间为60 min,反应温度为45℃,催化剂用量为22.5 g L-1,氯丙烯与双氧水的摩尔比n(AC):n(H2O2)=1.8,并对无机钛硅原料体系合成的TS-1进行了修饰改性,评价了其催化性能.     

TS-1分子筛的无机法合成及其催化苯酚羟基化性能

以无机固体硅胶和硫酸钛为原料,利用无机盐在多孔载体表面自发分散的基本原理,通过热处理先形成具有类似于钛硅分子筛Si-O-Ti键的无机SiO2-TiO2前驱体,然后以四丙基氢氧化铵为模板剂,通过水热晶化成功合成了TS-1分子筛.X射线衍射、傅里叶变换红外光谱和紫外-可见光谱表征表明,SiO2-TiO2前驱体中钛主要呈高分散状态,其中高分散的钛在水热晶化过程中基本进入了TS-1分子筛骨架,而以锐钛矿相存在的钛则基本不变.当SiO2-TiO2前驱体处理温度为450℃,SiO2/TiO2摩尔比为40,晶化温度为160～170℃,晶化时间为48～72h时,合成的TS-1分子筛对苯酚羟基化反应的催化活性最好,与经典有机法合成的TS-1分子筛的催化活性相当.     

钛硅分子筛TS-1的合成、表征及催化性能

钛硅分子筛TS-1自Taramasso等［1］首次报道合成以来,由于其优异的选择氧化催化 性能及其催化的反应具有对环境污染轻,反应条件温和等优点而备受关注. 钛硅分子筛的制 备及应用研究是分子筛催化领域中的热点之一. 在经典的合成体系中,四丙基氢氧化铵(TPAO H)常被用作模板剂［2］,这是钛硅分子筛价格较为昂贵的主要原因之一. 国内外学者 都致力于廉价合成体系的开发,Müller等［3］报道了以四丙基溴化铵(TPABr)作模板 剂合成钛硅分子筛. 对于钛源和硅源,人们往往都采用水解趋势较为缓和的钛酯和硅酯,以达 到钛源和硅源的匹配;在合成过程中,要预先将钛酯加入到乙酰丙酮或异丙醇溶剂中进行稀释 ,并对胶液进行蒸醇处理［2,3］. 这使得钛硅分子筛的合成过程更加复杂,并提高了 其合成费用. 本文以钛酸四丁酯(TBOT)和四氯化钛混合原料作钛源,成功地合成出对丙烯环 氧化具有优异催化性能的钛硅分子筛TS-1,避免了上述的复杂步骤,并降低了钛硅分子筛的成本.     

钛硅分子筛TS-1合成晶化气氛的影响

考察了不同晶化气氛(N2、H2、A ir、O2)对合成钛硅分子筛TS-1的影响,用XRD、IR和N2吸附/脱附对所合成的钛硅分子筛进行结构表征,发现在H2气氛下合成的TS-1结晶度最高,锐钛矿的含量最少;O2气氛下合成的TS-1中锐钛矿含量最高.以氯丙烯氧化为模型反应,考察了不同晶化气氛下合成的钛硅分子筛的催化活性和双氧水的利用效率.结果表明,在H2气氛下所合成的钛硅分子筛的双氧水的利用效率最高.     

钛硅分子筛催化1-丁烯环氧化研究

自1983年Taramasso等报导TS-1的合成以来，钛硅分子筛的合成及应用一直是分子筛催化领域的热点。经典TS-1合成方法采用四丙基氢氧化铵（TPAOH）为模板剂，合成成本较高、条件苛刻，限制了其应用。用四丙基溴化铵（TPABr）为模板剂代替TPAOH，能够成功地合成TS-1。不同孔道结构的钛硅分子筛，如Ti-β、Ti-MCM-41、Ti-HMS等弥补了TS-1较小孔径的缺点，进一步扩大了钛硅分子筛的应用。本文以不同合成方法得到的TS-1及中孔Ti—HMS为催化剂，双氧水为氧化剂，1-丁烯环氧化合成1，2-环氧丁烷，研究了不同钛硅分子筛对1-丁烯环氧化反应的催化性能。     

干胶转化法合成条件及磷酸处理对TS-1分子筛性能的影响

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,用干胶转化法合成TS-1分子筛.考察了TEOS水解时的水硅比、水解温度、除醇条件、晶化时间及磷酸处理对TS-1分子筛性能的影响.采用XRD、SEM、IR、ICP及N2吸附等手段对样品进行表征,同时以环己酮氨肟化反应考察样品的催化活性.结果表明,使用少量的TPAOH(n(TPAOH)/n(SiO2)=0.15)即可得到性能较好的TS-1,而用磷酸对所得TS-1分子筛处理则能进一步改善TS-1分子筛的性能.当n(SiO2):n(TPAOH):n(H2O)=1:0.15:16时在20℃下水解TEOS,钛硅溶液能自行胶凝,将所得凝胶在75℃下除醇至失重率达65%左右,晶化6d得到TS-1分子筛,产品经磷酸改性后,环己酮转化率达到99.5%,环己酮肟选择性达到98.7%,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.     

Ti-HMS分子筛的合成与表征

 以十二胺(DDA)为模板剂,采用室温晶化合成了钛硅中孔分子筛Ti-HMS,并用XRD,IR,UV-Vis和N2吸附对分子筛样品进行了表征,考察了配料硅/钛比、模板剂用量及晶化时间对合成分子筛的影响. 结果表明,Ti-HMS分子筛具有较大的比表面,孔径约为3 nm. 随着配料硅/钛比的降低,Ti-HMS分子筛的比表面积减小,进入骨架的钛量增多,且非骨架钛也增多. n(DDA)/n(SiO2)≤0.22时,随着模板剂用量的减少,Ti-HMS分子筛的结晶度下降,骨架钛含量减少,非骨架钛含量增加. 晶化时间在9~18 h最佳.     

无机SiO2-TiO2前驱体体系合成高性能TS-1分子筛

 在热处理条件下,使Ti(SO4)2在多孔硅胶表面自发分散形成具有类似于钛硅分子筛催化活性中心结构单元的Si-O-Ti键的SiO2 -TiO2前驱体,将该前驱体在模板剂四丙基氢氧化铵的作用下水热晶化得到了钛硅分子筛TS-1. X射线衍射、红外光谱和扫描电镜表征表明, TS-1分子筛晶化完全,钛原子已进入TS-1分子筛骨架. 苯酚羟基化反应测试结果表明,前驱体的热处理温度对合成的TS-1分子筛的催化性能影响很大,处理温度以450 ℃为宜.     

钛硅催化材料的研究进展 Ⅱ.钛硅分子筛TS-1的制备及其物化性能的研究

钛硅分子筛TS21由于其优异的催化氧化性能而受到极大关注。TS21的制备及基础研究是催化领域的一个热点。本文综述了近10年来钛硅分子筛TS21的制备研究进展, 讨论了在合成制备过程中模板剂、钛源、硅源、碱源、晶化条件等因素对钛硅分子筛TS21的影响, 并对其物化特点进行了评述。     

Synthesis and application of colloidal nanocrystals of the MFI-type zeolites

The colloidal dispersion containing the nanosized zeolites with the MFI topology has been successfully prepared. A pre-aging process of the mother gel at 80°C for 24 h before the crystallization was important for the formation of the nanosized zeolites. We have also found that silicalite-1 nanocrystals av. 62 nm in size were formed by the addition of acidic amino acids into the mother gel. The particle size of the zeolites can be controlled ranging from 62 to 530 nm by changing the amount of water, aging process, crystallization time and temperature and the addition of organic molecules. Furthermore, nanosized titanium silicalite-1 (TS-1) with the size of 50-130 nm has been successfully synthesized by the addition of a Ti source into the synthesis gel of the silicalite-1 nanocrystals. The nanosized TS-1 exhibits a higher catalytic activity in the epoxidation of cyclohexene than the microsized ones. Finally, we demonstrate the preparation of thin films of the silicalite-1 and TS-1 nanocrystals onto a silicon substrate by a dip-coating technique.     

Novel method for synthesis of titanium silicalite-1 (TS-1)

Titanium silicalite-1 (TS-1) was easily synthesized using inorganic silicon and titanium source, tetrapropylammonium bromide (TPABr) or TPAOH as templating molecule, NH3· H2O, HDA or TEAOH etc. as base sources. In this system, TPA cations (come from TPABr or TPAOH) served as tern-plating agents to direct the MFI structure. NH3H2O, TEAOH or HDA etc. provides the alkalinity necessary for crystallization. X-ray diffraction, UV-Vis, ER spectroscopies, SEM, 29 Si MAS NMR showed that the zeolites obtained possessed all the structural characteristics of TS-1, and titanium atoms were introduced into the framework in TS-1. This material was proved to have high crystallinity and high catalytic activity to allyl chloride epoxidation and propylene epoxidation. All the samples synthesized had similar catalytic properties with a standard TS-1 through compared inorganic reactant system with organic synthesis system using propylene epoxidation. The effects of silicon source and TPABr/SiO2 ratio were discussed.     

Study on the Ammoximation of Cyclohexanone to Cyclohexanone Oxime Catalyzed by Titanium Silicalite-1 Formed in Inorganic System

The conventional and modified synthesis of titanium silicalite-1 is in the organic system^[1,2]. We have reported the TS-1 could be prepared with colloidal SiO₂ and TiCl₃ as Si source and Ti source respectively in inorganic system^[3]. The present paper deals with the ammoximation of cyclohexanone to cyclohexanone oxime over TS-1 prepared by the method described above. Tests are carried out for 5 hours at 65℃,with NH₃ and H₂O₂ in the liquid phase, acetone as solvent, reactants adding to reactor all at once over these two kinds of TS-1. The results show that oxime yield over TS-1 produced in inorganic system is as good as or better than that catalyzed by conventional TS-1 at the same conditions. More over, more satisfied yield of oxinone could be achieved if it reacts at some optimal reaction conditions^[4,5]. In addition, the same result has been reached at the epoxidation of propylene catalyzed by these two kinds of TS-1 Following table is the results of reaction catalyzed by these two kinds of TS-1.     

Study on the Acid Treatment of Titanium Silicalite TS-1

Titanium silicalite (TS-1) is one kind of heteroatom molecular sieve synthesized by Taramasso and his coworkers in 1983^[1]. Its specific catalytic oxidation properties have attracted much attention of many scientists^[2]. The synthesis of TS-1 need use expensive TPAOH as the template; this restrains its industrial application. There are many reports on low cost TS-1, such as using TPABr to replace TPAOH, silica sol to replace tetra-ethyl orthosilicate^[3-5]. In our lab, TS-1 was synthesized by using TPABr as the template and silica sol as silicon source,and the amount of TPABr was decreased to 0.05 (TPABr/SiO₂). The as-synthesized TS-1 has some differences compared with TS-1 synthesized according to the standard method, such as large crystal size, trace aluminum, extra-framework titanium, high activity in the epoxidation of propylene with dilute H₂O₂ and low selectivity of propylene oxide (20-30%). The low selectivity of PO is attributed to the acidity of TS-1 resulted from the trace aluminum and silicon hydroxyl. In order to increase the selectivity of PO, it is necessary to add some base to the reaction mixture. Generally, acid treatment can remove aluminum and other elements and impurity to improve catalyst. In this paper, the effect of the acid treatment on the physicochemical properties of TS-1 was studied.     

钛硅酸盐分子筛TS－1的合成及表征

钛硅酸盐分子筛ＴＳ－１的合成及表征马淑杰，李连生，刘国宗，林文勇（吉林大学化学系，长春１３００２３）苏克，李莹（长春地质学院测试中心，长春１３００２１）关键词ＴＳ－１沸石，合成，苯酚，催化氧化＊～ｓ－ＺＳＭ－５沸石是Ｓ！Ｉ。。１ｕｅ－１沸石的衍生物，...     

以天然矿物为全部硅铝源低成本绿色合成ZSM-5分子筛的研究

ZSM-5分子筛被广泛地应用于催化、吸附分离、离子交换和绿色化工等领域,但目前其合成主要是以无机化学品为硅铝源,从源头来看是非绿色化的过程.我们以热活化的硅藻土和亚熔盐活化的累托土为全部硅铝源,通过调变两种矿物的加入比例调变合成体系的硅铝比,在水热合成体系中制备ZSM-5分子筛.系统地考察模板剂用量、碱度、投料硅铝比、晶化时间等合成条件对产物结构和性质的影响,并对在最优条件下合成的ZSM-5分子筛的物化性质进行了详细地表征,结果表明：以天然矿物为全部硅铝源可以合成出具有较高结晶度、晶粒尺寸约为4 μm的六面体挛晶形貌的ZSM-5分子筛,该分子筛比商业ZSM-5分子筛具有更高的水热稳定性和更优的加氢异构性能.     

A new way to Prepare ts-2 with Silica sol as Silicon Source

The addition of suitable amounts of aqueous ammonia into precursor gel with silica sol as silicon source, TS-2 with small particle size and high titanium content has been successfully synthesized. It displays the same excellent performance in hydroxylation of phenol as the sample prepared with TEOS as silicon source.     

干胶法制备钛硅沸石及其催化性能

以四丙基溴化铵为模板剂,以乙二胺(EDA)为碱源,采用干胶法制备了TS-1,并在此基础上引入介孔/大孔模板剂蔗糖而制备出多级孔道TS-1.采用X射线衍射、紫外-可见光谱及N2物理吸附-脱附等手段对所得样品进行了表征,并考察了它们催化噻吩(Th)及苯并噻吩(BT)氧化反应的性能.结果表明,随着釜底部n(EDA)/n(H2O)比的降低,TS-1结晶度、骨架Ti含量及其在Th氧化反应中的催化活性均升高.而当以乙胺和正丁胺为碱源时,TS-1难以晶化.所制备的多级孔道TS-1样品具有介孔/大孔孔道,在Th氧化反应中的催化活性高于TS-1;对于BT的氧化,当n(sucrose)/n(SiO2)为0.35时,制备的多级孔道TS-1样品的催化活性最高,BT脱除率可达100%,而TS-1则无催化活性.     

Synthesis, structure, and reactivity of a new Ti-containing microporous/mesoporous material

A new class of porous, mixed phase titanosilicate materials containing a microporous TS-1 phase and a mesoporous Ti-MCM-48 phase has been successfully synthesized. A novel, one-pot synthesis method was used in which the organic templates for the mesoporous and microporous phases were added sequentially to the same reaction mixture, followed by crystallization at 150 degrees C. The gemini surfactant 18-12-18 was used to form the Ti-MCM-48 mesophase; subsequent addition of tetrapropylammonium cation (TPA+) led to the formation of TS-1. The relative amounts of the two phases within the final products were controlled by optimizing the crystallization time. Crystallization times between 12 and 50 h gave materials containing both phases, with an increasing amount of microphase formed at longer crystallization times. These materials, called "Ti-MMM-2" (microporous/mesoporous materials) were characterized using powder XRD, N2 physisorption, TEM, FTIR, DR-UV/Vis spectroscopy, and 29Si MAS NMR. In the epoxidation of cyclohexene with tert-butyl hydroperoxide (TBHP), Ti-MMM-2 samples exhibited higher catalytic activity (approximately 61%) than either TS-1 (16%) or Ti-MCM-48 (42%), with a very high selectivity (97%) for formation of cyclohexene oxide.