| Abstract: | 2,3,5-三甲基苯?是合成維他命E之前趨物，本論文研究催化2,3,6-三甲基苯酚之氧化反應(TBHP為氧化劑)以合成2,3,5-三甲基苯?的觸媒，觸媒是以銅化合物為活性點附著在不同載體的觸媒，載體種類有：SiO2、MCM-41、MCM-48及溶膠-凝膠法製備的SiO2，探討這些觸媒對催化2,3,6-三甲基苯酚反應之影響。另外我們對這些觸媒做BET、ICP-AES、XRD、FTIR、TPR、TEM和ESCA等特性分析，以了解這些觸媒的特性。並進行了此氧化反應之動力學的探討。 催化2,3,6-三甲基苯酚之反應結果顯示，觸媒對氧化反應的產率與選擇率的順序為：CuCl/MCM-48>CuCl/MCM-41>CuCl/SiO2>CuCl/SiO2(area800)>CuCl/SiO2(area400)>CuCl/SiO2(sol-gel)。以MCM-48為載體的銅觸媒之產率與選擇率為最好。 由TPR實驗結果得知，附著在SiO2、MCM-41及MCM-48載體的CuO是在載體表面，容易由Cu2+直接還原成Cu，因此只有一個波峰，而附著在sol-gel載體上的CuO可能有兩種型式，一種是在載體表面，另一種是被包附在載體裡，因此表面的CuO會先還原形成第一個波峰，溫度升高被包附在載體裡的CuO再被還原形成第二個波峰。由TPR實驗結果與2,3,6-三甲基苯酚催化反應結果比較發現TPR有兩個波峰的觸媒，活性較差，因此其反應性比一個波峰的觸媒差。
This thesis studied several copper-containing catalysts for catalyzing the reaction between 2,3,6-trimethylphenol(TMP) and aqueous TBHP. The major product is 2,3,5-trimethyl-1,4-benzoquinone (TMBQ), which is the precursor for the synthesis of Vitamin E. Several support were used for preparing the catalysts, including SiO2, MCM-41, MCM-48 and sol-gel prepared SiO2. The effect of support on the catalyst performances were investigated. In addition, BET, ICP-AES, XRD, FTIR, TPR, TEM and ESCA were used to characterize the catalysts in order to have better understanding of the catalyst performances. Experimental results show that the catalysts have the following order of catalytic performances：CuCl/MCM-48>CuCl/MCM-41>CuCl/SiO2>CuCl/SiO2(area800)>CuCl/SiO2(area400)>CuCl/SiO2(sol-gel). Among the catalysts studied, CuCl/MCM-48 had the best selectivity and yield. TPR results indicated that CuO supported on SiO2, MCM-41 and MCM-48 was easier to reduce from Cu2+ to Cu, and showed a single reduction peak. CuO supported on sol-gel prepared SiO2 showed two reduction peaks, which corresponding to the reduction from Cu2+ to Cu+, and from Cu+ to Cu. The TPR result and the results of 2,3,6-TMP oxidation suggest that the catalysts had two reduction peaks had worse performances that the catalysts with a single reduction peak. |
