交聯高分子擔負釩金屬錯合物之合成及催化應用

Abstract

將催化劑固定在固態載體上，使之具有回收再利用的特性，並達成綠色化學目標，是此研究之課題。相較一般無機固態載體，交聯高分子提供了與反應物之間的親和力，提升催化的效率。在本篇論文中利用原子轉移聚合(atom transfer radical polymerization，ATRP)的方法合成不同長度的聚丙烯酸甲酯(PMAn)，分別與兩種不同交聯劑CL1及CL2進行交聯反應，使其結構變的更穩定之材料，進一步在溫和的鹼性水溶液下將高分子的酯基部份水解為羧酸根。爾後在中性水溶液下與釩金屬形成所有溶劑不溶性的高分子錯合物，並以紅外線吸收、固態紫外線-可見光吸收光譜及誘發耦合電漿質譜鑑定。 以PMA28CL1-COO-VO作為催化劑，叔丁基過氧化氫(tert-butyl hydroperoxide，TBHP)為氧化劑，於60 ℃、15小時內可將環辛烯完全轉換成環氧化的產物；若使用過硫酸氫鉀(KHSO5)，則在室溫下亦可得到相同結果。在類似的反應條件下進行一系列烯類的氧化，反應結果則是依氧化劑的使用量多寡，可以得到二醇類或是氧化裂解的產物。此類型催化劑進行催化反應後，存留於水層中而且仍保有活性，回收再利用5次以上仍維持90 ％的活性。

The main focus of this study is to immobilize the catalysts on the solid supports and make them recyclable. Compared with the general inorganic supports, the cross-linked polymer supports promoted the activities of the catalysts by providing the affinity with the reactants. Here, we synthesized poly(methyl acrylate) with different chain lengthes via atom transfer radical polymerization (ATRP), and turned it into more stable material by reaction with two kind of cross-linker CL1 and CL2 respectively, and then hydrolyzed the ester group into the carboxylate functional group under basic aqueous solution, followed by reaction of VOSO4 under neutral aqueous solution to afford the insoluble polymer complexes, which were characterized by IR、solid UV、and ICP-MASS。 This complex could be used to catalyze cyclooctene into cyclooctene oxide completely with TBHP (tert-butyl hydroperoxide) under 60 ℃ in 15hr, and the same experiment result could be reached by replacing TBHP with KHSO5 at the room temperature. Besides, a series of oxidation of olefins were performed under similar reaction condition, and the final products gave either the diols or the acids from the oxidative cleavage depending on the amounts of the oxidants used in the reaction. This type of catalyst would remain in the water layer and still mantained 90 ％ activity after 5 times recycled.