含有機催化劑之中孔洞材料的開發及應用
Abstract
進入21世紀，科技發展使人們可以掌握物質更小的尺寸，到了奈米的時代，在諸多奈米材料中，多孔性材料是目前科學研究及工業技術發展上重要的課題之一。1992年由Mobil Oil公司開發出一系列具有高表面積、高熱穩定性、孔洞大小規則一致及易於調整孔洞大小等優點的M41S系列後，吸引了許多科學家的興趣與重視，奈米材料的專題研究更如雨後春筍般的大量出現。
本實驗站在發展已臻於成熟的奈米材料上，結合有機催化劑，成功發展出連結有機、無機、奈米科技及材料科學的新催化劑，此催化劑不同於以往需利用共價鍵形式將有機物與無機材料產生鍵結，而僅是將有機催化劑關在中孔洞材料內，在發生反應的時候，因為催化劑的自由度更大，因此更接近勻相催化。並利用此催化劑以對-硝基苯甲醛和環己酮作為反應物，催化不對稱醇醛縮和反應。藉由改變溶劑、中孔洞材料及反應條件等，探討對產物鏡像選擇性的影響。最後篩選出利用飽和食鹽水作為反應之最佳溶劑，可達到大於95%的產率以及優越的非鏡像選擇性anti/syn = 95/5 和主產物鏡像超越值91 % ee。亦可利用其非勻相特性，達到催化劑回收重複使用的效果。
We have successfully synthesized organocatalyst of L-proline derivative functionalized mesoporous silica materials using post-synthesis method with high overall chemical yield. The features of the organic-inorganic hybrid material were characterized with low angle X-ray diffraction, N2 surface sorption analysis, elemental analysis, TEM, SEM and solid state 13C CP-and 29Si DP-MAS NMR. We used it as a heterogeneous chiral organocatalyst in asymmetric aldol reaction. Diastereo- and enantio-selectivity obtained in aldol reaction with L-proline derivative functionalized heterogeneous catalyst is comparable to those with the homogeneous counterpart. We also synthesized camphor derived organocatalyst. The new organocatalyst was successfully used as a catalyst for asymmetric aldol reaction to achieve high yield (94%) and stereoselectivity (anti/syn = 93/7, 84% ee). Finally, we studied the cage or gate-like system and the result indicated that this was a better performance when the catalysts in a nanopore. The development of novel chiral organocatalysts and the incorporation on the mesoporous materials are in progress and further applications will be reported.
We have successfully synthesized organocatalyst of L-proline derivative functionalized mesoporous silica materials using post-synthesis method with high overall chemical yield. The features of the organic-inorganic hybrid material were characterized with low angle X-ray diffraction, N2 surface sorption analysis, elemental analysis, TEM, SEM and solid state 13C CP-and 29Si DP-MAS NMR. We used it as a heterogeneous chiral organocatalyst in asymmetric aldol reaction. Diastereo- and enantio-selectivity obtained in aldol reaction with L-proline derivative functionalized heterogeneous catalyst is comparable to those with the homogeneous counterpart. We also synthesized camphor derived organocatalyst. The new organocatalyst was successfully used as a catalyst for asymmetric aldol reaction to achieve high yield (94%) and stereoselectivity (anti/syn = 93/7, 84% ee). Finally, we studied the cage or gate-like system and the result indicated that this was a better performance when the catalysts in a nanopore. The development of novel chiral organocatalysts and the incorporation on the mesoporous materials are in progress and further applications will be reported.
Description
Keywords
有機催化劑, 中孔洞材料