有机—无机杂化超微孔材料和MFI型金属杂原子分子筛的合成

发布时间：2018-12-21 13:12

【摘要】：超微孔材料因拥有1-2nm介于微孔沸石和介孔分子筛之间的孔道结构,在催化反应中既表现出良好的扩散性,又拥有很好的择型选择性,因此具有很大的潜在研究价值。本文第一部分,研究了有机-无机杂化超微孔材料的制备及其在吸附反应中的应用。以正硅酸乙酯(TEOS)和(3-氯丙基)-三甲氧基硅烷(CPTMS)作为硅源,十六烷基三甲基溴化铵(CTAB)作为模板剂,环糊精作为助模板剂。通过CTAB分子可以进入β-环糊精分子的空腔形成自组装包合物,进而导向合成有机-无机杂化超微孔二氧化硅材料。通过盐酸乙醇溶液回流的方法除去CTAB和环糊精模板剂,进而得到有机-无机杂化超微孔材料。通过XRD、FTIR、SEM-EDS、TEM、BET等方法对制备的超微孔材料进行表征,结果表明CTAB和环糊精双模板剂成功介导了有机-无机杂化超微孔材料的合成。TEM和BET结果表明,合成的超微孔材料孔径在1.2-1.5nm之间。吸附结果表明,合成的超微孔材料在吸附罗丹明B溶液的反应中,吸附量高达340mg/g,吸附平衡时间为10min,材料重复利用三次以上的吸附率仍在95%以上。MFI型金属杂原子分子筛,在丙烯选择性氧化、环己酮氨肟化和苯酚羟基化等反应中广泛应用。本文第二部分,研究了金属杂原子微孔分子筛的合成。以正硅酸乙酯(TEOS)为硅源,钛酸四丁酯(TBOT)、硝酸铁、硝酸镍、硝酸铬为杂原子金属源,以三乙醇胺(TEA)为络合剂,以四丙基氢氧化铵(TPAOH)为结构导向剂,用干凝胶法通过挤压成型成功制备了含钛、铁、镍、铬的M-MFI(M=Ti、Fe、Ni、Cr)型微孔分子筛。同时分别研究了硅油(PDMS)、TPAOH、TEA和含水量对材料尺寸和结晶度的影响。通过XRD、FTIR、UV-vis、SEM、BET等方法对M-MFI分子筛进行表征。UV-vis结果表明金属杂原子成功进入分子筛骨架结构。XRD和FTIR结果表明,成功合成MFI型金属杂原子分子筛,通过对铁硅分子筛的不同TPAOH和TEA含量的研究表明,四丙基氢氧化铵量越大,铁硅分子筛晶粒聚集越紧密,三乙醇胺量越大,分子筛尺寸越大。通过对钛硅分子筛不同含水量的结晶度研究表明,当含水量降到最小10%时,相对结晶度可达到100%,钛硅分子筛径向强度随着PDMS加入而增强,最优比例为PDMS/Si为0.024。实验结果表明,通过干凝胶法,用较少量的结构导向剂TPAOH和少量的水,一步成型合成出含钛、铁、铬、镍的成型杂原子分子筛。避免传统工艺中的过滤和洗涤,降低了催化剂的生产成本,最大限度上减少了废水的产生。
[Abstract]:Because of the pore structure of 1-2nm between microporous zeolite and mesoporous molecular sieve, the ultraporous material has good diffusion and selectivity in catalytic reaction, so it has great potential research value. In the first part, the preparation of organic-inorganic hybrid ultraporous material and its application in adsorption reaction were studied. Ethyl orthosilicate (TEOS) and (3-chloropropyl) -trimethoxysilane (CPTMS) were used as silicon source, cetyltrimethylammonium bromide (CTAB) as template and cyclodextrin as template. The CTAB molecule can enter the cavity of 尾 -cyclodextrin molecule to form a self-assembled inclusion compound, which leads to the synthesis of organic-inorganic hybrid ultraporous silica materials. CTAB and cyclodextrin templates were removed by reflux of hydrochloric acid ethanol solution, and then organic-inorganic hybrid ultraporous materials were obtained. The ultraporous materials were characterized by XRD,FTIR,SEM-EDS,TEM,BET. The results showed that the synthesis of organic-inorganic hybrid ultraporous materials was successfully mediated by CTAB and cyclodextrin, and the results of TEM and BET showed that, The pore size of the synthesized ultraporous material is between 1.2-1.5nm. The adsorption results showed that the adsorption capacity of the synthesized ultraporous material was 340 mg / g, and the adsorption equilibrium time was 10 min in the adsorption reaction of Rhodamine B solution. The adsorption rate of the reused materials is still over 95%. MFI metal hetero-atomic molecular sieves are widely used in propylene selective oxidation cyclohexanone ammoximation and phenol hydroxylation. In the second part of this paper, the synthesis of metal heteroatom microporous molecular sieve was studied. Tetrabutyl titanate (TBOT), iron nitrate, nickel nitrate, chromium nitrate as heteratomic metal source, triethanolamine (TEA) as complexing agent, tetrapropylammonium hydroxide (TPAOH) as structure guiding agent were used as silicon source, tetrabutyl titanate (TBOT), as silicon source, nickel nitrate and chromium nitrate as heteroatomic metal source. M-MFI microporous molecular sieves containing titanium, iron, nickel and chromium were successfully prepared by xerogel method. At the same time, the effects of (PDMS), TPAOH,TEA and water content of silicone oil on the size and crystallinity of the materials were studied. M-MFI molecular sieves were characterized by XRD,FTIR,UV-vis,SEM,BET. The results of UV-vis showed that the metal heteroatoms entered the molecular sieve skeleton structure successfully. The results of XRD and FTIR showed that the MFI molecular sieves were successfully synthesized. The different TPAOH and TEA contents of Fe-Si molecular sieve show that the larger the content of tetrapropyl ammonium hydroxide, the closer the grain aggregation, the larger the triethanolamine content and the larger the molecular sieve size. The crystallinity of titanium-silicon molecular sieve with different moisture content was studied. When the water content was reduced to the minimum of 10, the relative crystallinity could reach 100. The radial strength of titanium-silicon molecular sieve increased with the addition of PDMS, and the optimum ratio was 0.024. The experimental results show that hetero-atomic molecular sieves containing titanium, iron, chromium and nickel are synthesized by one step method with a small amount of TPAOH and a small amount of water by xerogel method. To avoid filtration and washing in traditional process, the production cost of catalyst is reduced, and the production of wastewater is minimized.
【学位授予单位】：曲阜师范大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ424.25;O643.36

【相似文献】