【作者】 王洪林；

【导师】 王祥生；

【作者基本信息】 大连理工大学 ， 工业催化， 2000， 博士

【摘要】 钛硅沸石是八十年代发现的一类新型沸石分子筛催化材料。钛硅沸石能活化双氧水进行一系列的选择性氧化反应。反应条件温和而且选择性高不产生污染性废物。这类催化材料出现后一直受到人们很大的重视并用它开发了一系列环境友好的选择性氧化新工艺过程。 但是，经典的钛硅沸石合成方法成本昂贵，合成条件苛刻，限制了它的进一步发展和广泛应用。经典法得到的钛硅沸石TS-1晶粒小，回收困难。为了克服经典的钛硅沸石的这些问题，也为了提高和改进钛硅沸石类催化材料的催化性能和应用性能，很多研究者从钛硅沸石合成方法、钛硅沸石的活性结构等不同角度进行研究，开发了很多新的制备方法和新的钛硅氧化物催化材料。用四丙基溴化铵代替四丙基氢氧化铵为模板剂可以在很大程度上降低钛硅沸石的合成成本。在钛硅沸石的水热合成体系中加入新物种，改变水热晶化过程以获得新结构的的催化材料，是一个新的研究方向。另外，用溶胶凝胶法获得钛离子在硅氧体中高度分散的混合氧化物催化材料，也是一个新的研究热点。本论文从上述两个研究方向着手，研究了几种新的钛硅催化材料的合成制备方法，得到了一些具有新的催化结构的催化剂。在获得一些有优良应用效果的催化材料的同时，从新的角度开拓了对钛硅氧化物类催化材料的认识。 本论文的主要研究内容如下：一、原位栽植法合成TS/TiO₂复合催化材料 以四氯化钛或钛酯经水解制备有特定结构的无定形二氧化钛。将这种在水热条件下能发生较大结构和表面变化的活性二氧化钛加入到以四丙基溴化铵为模板剂的水热合成TS-1沸石的胶液中，二氧化钛基质和沸石成晶的前体硅氧化物胶体组分在水热条件下发生较大的相互作用，形成了一种在二氧化钛中含有纳米沸石相的具有新的活性催化结构的TS/TiO₂复合催化材料。 TS／TiO₂的XRD衍射谱在2θ角8到10度间的双峰和23到25度间的三重峰表明其中存在MFI沸石结构。但这些MFI沸石的特征衍射峰都很弱小。以高结晶度的TS-1和TiO₂的混合物为参比，以 2θ角23到25度 摘 要间的三重峰面积计算XRD结晶度。与 TSA和 TIO。混合物有相同二氧化钛含量的 TS／TO。的 XKD结晶度只有 30wt0％。样品焙烧后在 2 0角 26度处出现一强衍射峰，该峰为无定形二氧化钛焙烧后转变为锐钛矿型二氧化钛而产生的。焙烧后的TS／TIO。样品的IR光谱在960cm”’处有明显的特征吸收，在谱图的 400到 600 cm”’处出现了二氧化钛的吸收带与 MFI沸石特征的550 cm’‘的吸收峰及硅氧体共有的450 cm”’处的吸收峰的叠加使两个吸收峰间的分化程度降低。但 550 cm”‘的吸收峰强度与 450 cm”’处的吸收峰强度比I。。M。。不小于0．7，这说明TS／TIO。的沸石相IR结晶度很高。原粉样品的 CI3 CPMAS NMR谱也说明有包含在 MFI沸石孔道中的四丙基铰模板剂分子。样品的高分辨率透射电镜（TEM）表明 TS／TO。存在看纳米尺寸的颗粒。TS／TIO。的XRD结晶度低而IR结晶度高也意味着样品含有纳米沸石晶相。 TS／TIO。的f刀V光谱吸收峰在250nxn处出现，这与常规钛硅沸石在210～220urn处出峰的骨架钛吸收有较大的不同。从紫外谱峰的位置得知TS／TIO。的钛物种为一种高分散的非骨架钛。TS／TIO。的UV丑aman谱没有TS4骨架钛特征的 1120cm”’处的强共振信号，也说明该催化材料的活性催化结构不同于常规钛硅沸石。 将TS厅。应用于烯烃环氧化反应中。在以双氧水为氧化剂环氧化丙烯的反应中，TS／TIO，的活性略比标准的TS上高。适当的反应条件下双氧水转化率大于95％，环氧丙烷的选择性大于95％。而将无定形二氧化钛基质用于丙烯环氧化反应，不生成烯烃环氧化产物却分解双氧水；将在540℃焙烧后转化为锐钛矿相的二氧化钛基质用于丙烯环氧化反应，主成烯烃环氧化产物很少，但双氧水也很少分解。因此我们认为，含锐钛矿相的二氧化钛基质不是活性催化组分但也不分解双氧水；在TS／TIO，中起催化作用的是纳米沸石相中缺陷结构上的非骨架钛物种。将TS几。用于苯乙烯氧化反应时对深度氧化产物苯甲醛的选择性好，这与选择生成苯乙醛的TS．1有较大的不同。 将TS／TIO，用于环己酮氨氧化反应和苯酚羟基化反应中发现，催化活性都远低于标准的TS－1。说明TS／TIO，的新的活性结构对这两种反应催化效果差。 11 摘 要二、原位栽植法合成TS侣。复合催化材料 将无定形二氧化硅用钛酯进行表面处理后，将这种含表面活性钛物种的二氧化硅基质加入到四丙基漠化铰为模板剂的水热合成TS－1 沸石的胶液中。经永热晶化后得到TS沼。复合催化材料。TS沼。的XRD结晶度很高，”有典型的大晶粒MFI沸石的特征。其红外光谱表征有960 cm－’的特征吸收峰，y－U’V谱显示TS侣。包含骨架钛和非骨架钛物种。扫描电镜下发现TS更多还原

【Abstract】 TS-1 zeolite with Ti(IV) in the framework of silicalite-1 is a new kind of zeolite catalyst developed in 1980s. It was found that TS-l has unique catalytic properties. It can activate aqueous hydrogen peroxide to oxide many organic compounds selectively. These oxidation reactions carried out at ambient conditions (near room temperature) with little byproducts. The titanium silicalite catalysts have attracted much attention and many environment-friendly selective-oxidation processes have been developed based on TS-1-H2O2 oxidation system.However the synthesis of standard TS-l requires large amount of expensive reagents and severe operation conditions. The standard TS-l is difficult to handle due to its small crystal size. To overcome these problems and to improve the catalytic property of this kind of the catalysts, researches have been made to search for the new synthesis routes of titanium silicalite and to develop the titanosilicate catalysts with new active catalytic structure. Add a new material to hydrothermal synthetic gel of titanium silicalite to prepare a complex catalyst in situ is a new research area. Prepare the TiO2-SiO2 mixed oxide with highly dispersed titanium species through sol-gel process is also a hot research area.The dissertation studies the above new research area and provided some new catalysts with novel catalytic properties. (1) Prepare TS/TiO2complex catalyst through in situ plantingSome amorphous Ti02 was prepared through hydrolyzation of TiCl4 or TBOT. The amorphous TiO2 was added to the synthetic gel composed of tetrapropylammonium bormide (TPABr), silica sol. a titanium source and a base solution. In hydrothermal crystallization condition, the titaniumsilicalite was growing on the amorphous TiO2. The complex catalysts TS/Ti02 in witch the titania and silicalite have strong interaction have new active catalytic structure.The X-ray diffraction (XRD) patterns of the TS/TiO2 catalysts exhibit lowcrystallinity. The triple peaks at 2 6 23 to 25 degrees indicate the catalysts contain MFI structure. However the triple peaks are small and the crystallinity calculated by the triple peaks is only about 30 to 40%. The XRD patterns of the calcined samples exhibit a new peak at 2 6 26 degrees which means the amorphous titania transform to anatase after calcined at 540 . The IR spectra of the samples show a strong adsorption band at 960 cm-1. The IR crystallinity calculated by 1550/I4SO is high- The C13-CP-MAS NMR of the as-synthesized sample show the typical signal of occluded TPA molecule in the micro pore of MFI zeolite. The high-resolution TEM photographs of the catalyst samples show the nanostructured titanosilicate contained in the titania substrate.The RF-UV spectra of TS/TiO2 exhibit an adsorption peak at 250nm which is different from the framework titanium adsorption of the common titanium silicalite which peaks at 210-220nm. TS/TiO2 contains a new kind of active titanium species. The .UV-Raman spectra of TS/TiO2 do not exhibit the resonance signal-of framework titanium at 1120cm-1 that also means the catalyst contains new catalytic structure.The TS/TiO2 catalyst is applied to catalyze the epoxidation of propylene witfe atpieous hydrogen peroxide. The initiated catalytic activity of the catalyst is higher than the standard TS-1 catalyst. The conversion of the hydrogen peroxide is higher than 95% and the selectivity of the propane oxide is higher than 95% at some conditions. The amorphous titania exhibits high activity in decomposition of H2O2 while the calcined titania (anatase) dose not decompose H2O2 but also has little catalytic activity for epoxidation reactions. The active catalytic center in TS/TiO2 is the highly dispersed non-framework titanium on the nanostructured MFI zeolite. TS/TiO2 was also applied to oxide ethylenebenzene .vwth H2O2 TS/TiO2 catalyst shows different product selectivity compared with The TS-1 catalyst.However thd catalytic activity of the TS/TiO2 in the ammoxidation of cyclohexandne and hydroxylation of phenol is very low compare更多还原