摘要
以白碳黑为硅源 ,偏铝酸钠为铝源 ,六亚甲基亚胺 (HMI)为结构导向剂 ,采用动态水热法合成了MCM 2 2 ,UTM 1和kenyaite ,并考察了硅铝比对产物晶相的影响 .结果表明 ,配料硅铝比是影响产物晶相的重要因素 .n(SiO2 ) /n(Al2 O3) =30～5 0时 ,晶化产物为MCM 2 2 ;n(SiO2 ) /n(Al2 O3) =71～ 1 90时 ,晶化产物为MCM 2 2与kenyaite的混合物 ,且随着硅铝比的增大 ,MCM 2 2的含量逐渐减少而kenyaite的含量逐渐增加 ;n(SiO2 ) /n(Al2 O3) =2 2 8～ 6 0 9时 ,晶化产物为八元环结构的UTM 1 ;不含铝源时 ,晶化产物为kenyaite .就合成MCM 2 2和UTM 1而言 ,凝胶中的铝是必不可少的 .上述几种晶化产物均呈片状 。
The unique porous network of MCM 22 suggests its potential use in a variety of catalytic processes. However, it is difficult to synthesize MCM 22 with high silica because the increase of SiO 2/Al 2O 3 ratio in the gel often leads to contaminated zeolites. The synthesis of MCM 22, UTM 1 and kenyaite by rotating hydrothermal crystallization method, using fumed silica, sodium aluminate and hexamethyleneimide (HMI) as raw materials, was investigated. It was found that SiO 2/Al 2O 3 ratio in the gel was an important factor affecting the product composition. When n (SiO 2) / n (Al 2O 3) =30～50, the product was MCM 22, and when n (SiO 2) / n (Al 2O 3) =71～190, the product was a mixture of MCM 22 and kenyaite. The fraction of MCM 22 decreased while that of kenyaite increased with the decrease in alumina content. When n (SiO 2) / n (Al 2O 3) =228～609, 8 membered ring UTM 1 was obtained. Pure layered silicate kenyaite was obtained in the absence of alumina in the gel. The presence of alumina in the gel system was critical for the formation of MCM 22 and UTM 1, but it was not the case for kenyaite. In the synthesis of UTM 1, a shorter induction time was observed. MCM 22, UTM 1 and kenyaite could be distinguished from each other by SEM though they all had platelet morphology.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2004年第7期542-546,共5页
