离子胶束诱导微波合成SAPO-11分子筛微球

以十六烷基三甲基氯化铵(CTAC)与正丁醇(n-butanol)形成的胶束为外模板, 采用微波法制备了SAPO-11分子筛微球.考察了CTAC浓度、晶化时间以及HF用量对SAPO-11分子筛形成的影响, 并利用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、热分析(TG-DTA)、电子衍射能谱(EDS)和N2物理吸附等技术对所得产物进行了系统表征. 结果表明: 当c(CTAC)+c(n-butanol)=0.180 mol·L-1时可得到结晶度较高的SAPO-11分子筛微球; 延长反应时间, 所得产物结晶度逐渐提高; 适量的HF, 有助于分子筛中Si物种的取代以及分子筛微球的形成. 通过对比实验, 提出了离子胶束诱导微波合成SAPO-11分子筛微球的反应机理.

Synthesis of SAPO-11 Molecular Sieve Microspheres Using a Microwave Technique and Mediated by Ionic Micelles

Micelles formed by cetyltrimethylammoniumchlorine (CTAC) and n-butanol were used as shape-directing templates to synthesize SAPO-11 molecular sieve microspheres by a microwave technique. Effects of CTAC concentration, time of crystallization, and dosage of HF were investigated. Properties of the products were characterized systematically by X-ray powder diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), thermal analysis (TG-DTA), electron diffraction spectroscopy (EDS) and N2 physisorption. When c(CTAC)+c(n-butanol)=0.180 mol·L-1, SAPO-11 molecular sieve microspheres with the preferred crystallinity were obtained. The crystallinity of the synthesized SAPO-11 molecular sieve microspheres was improved by prolonging the reaction time. The substitution of Si species and the crystallization of SAPO-11 molecular sieve microspheres were also improved by appropriate usage of HF. Using control experiments, the reaction mechanism for the crystallization of SAPO-11 molecular sieve microspheres as mediated by ionic micelles and using the microwave technique is proposed.