介孔材料的催化應用與微晶型孔壁的合成

Abstract

本論文分為二個部分，第一部分主要探討異相觸媒在Kharasch reaction上的應用，第二部分在探討如何合成含微晶型孔壁的中孔洞材料，使得中孔洞的觸媒材料有更好的催化活性。 Kharasch reaction亦被稱為Atom transfer radical cyclisation (ATRC)，經常用於合成多環分子，Kharasch reaction的催化劑一般都是同相觸媒，但同相觸媒容易引起分離、產物毒化等問題，本論文嘗試將Kharasch reaction的催化劑－CuCl/Bipyridine 利用物理吸附與介孔洞材料結合形成異相觸媒，並利用此異相觸媒催化反應，實驗結果顯示利用較大孔洞的SBA-15為載體的觸媒可得到較高的反應活性，此外若使用微波爐更可進一步加速反應的進行。 第二部分則是嘗試把介孔二氧化矽SBA-15材料的非晶型骨架反應生成晶型微孔壁。用來合成含晶形微孔壁之介孔二氧化矽材料的骨架的模板試劑為tetrapropylammonia bromide (TPABr)，為合成ZSM-5沸石的模板試劑。方法是先合成出具有良好孔洞結構的介孔SBA-15二氧化矽材料，以未移去模板試劑的SBA-15作為矽源，探討合成SBA-15的反應條件以及不同pH值及不同水熱時間下進行沸石結晶反應對最後產物結構的影響。在尋得最佳化條件後，將引入鋁離子於SBA-15骨架上，並比較含晶型微孔壁對含鋁SBA-15 酸性的影響。

This thesis is composed of two parts: the first part focuses on the application of heterogeneous catalysts in Kharasch reaction; the second part focuses on the synthesis of the ZSM-5 crystalline framework in the structure of SBA-15 in order to improve the catalytic activities. In the first part, CuCl/bipyridine catalysts were immobilized to mesoporous materials including SBA-15, SBA-1 and MCM-41 with or without amino-functional groups by absorption in solvents. The supported catalysts were used for cyclisation of unsaturated tri-halogenated compound. These kinds of cyclisation reactions are also called Kharasch reaction which is often catalyzed by homogeneous catalysts. The Cu (I) catalyst was easily leached when CH2Cl2 was the solvent, while the leaching problem was avoided by using toluene as the solvent. Although pure CuCl/bipyridine is not as efficient in catalyzing Kharasch reaction in toluene as in CH2Cl2, higher reaction rate was obtained in toluene over the supported materials. The activity and recycling of the catalysts were discussed. In addition, the effects of different supports, microwave technology, and the combination of ionic liquid in Kharasch reaction were studied. In the second part, we tried to synthesize ZSM-5/SBA-15 composite materials. Both ZSM-5 and SBA-15 are porous SiO2 material. ZSM-5 has crystalline framework and relative high acidity. It is an effective catalyst in many acid-catalyzed reactions. However, its pore size limits its applications from reactions involving macromolecules. SBA-15 has an ordered mesoporous structure, good thermal stability, but a relatively low acidity because its framework is amorphous. The purpose of this work is to transform the amorphous framework of mesoporous SBA-15 to the crystalline microporous wall. Tetrapropylammonia bromide (TPABr) was used as the template to synthesize crystalline framework and as-synthesized SBA-15 (without calcination) is the silicon source. The reaction conditions including pH value and the reaction time of crystallization for the synthesis of SBA-15 were varied to find the optimal reaction condition. In addition Al3+ ions were introduced to the framework of SBA-15 to examine the acidity of the Al-SBA-15 materials.