利用含胺基之短孔道介孔 SBA-15 催化二氧化碳與環氧化物之環加成反應

Cycloaddition of CO2 to Epoxide Catalyzed by Short-channel Amino-functionalized SBA-15

黃品瑄(Ping-Hsuan Huang)

指導教授 ： 鄭淑芬

國立臺灣大學/理學院/化學研究所/碩士(2018年)

https://doi.org/10.6342/NTU201802794

摘要

二氧化碳為目前最主要的溫室氣體來源，主要是由燃燒石油及煤炭所產生，隨著溫室效應而造成氣候變遷日趨嚴重，Carbon dioxide capture and storage (CCS) 的相關研究備受矚目，而近年來科學家們更將研究聚焦於如何將二氧化碳轉換成具有工業及經濟價值的化合物。本研究以一鍋合成法製備含不同胺基官能基之短隧道 SBA-15 分子篩，探討的胺基官能基包括 guanidine (gua)、diamine (dia) 與 propylamine (NH2)，所得觸媒材料利用 XRD、N2 sorption isotherm、SEM、EDS、EA、ICP-MS、TGA、Solid state NMR 及 FT-IR 等技術鑑定，得知材料之結構、形貌、元素比例，並證實胺基官能基成功鑲嵌於二氧化矽骨架中。之後將所合成出之觸媒應用於二氧化碳與環氧化物之環加成反應，所得到產物環狀碳酸鹽則利用 GC-FID 偵測產率。先從催化反應之變因尋找最佳化反應條件，變因包括觸媒添加量、反應溫度、反應物比例及反應時間。發現以 10%gua-Zr-SBA-15-at 作為觸媒，加入 CO2/epoxide 比為 3.2 之二氧化碳於 140°C 下反應 18 h 可得到 71% 之產率；而以棒狀長隧道 10%gua-r-SBA-15-at 作為觸媒在相同條件下反應則得到 48% 的產率，顯示短隧道有利反應物在 SBA-15 內擴散並接觸催化活性中心。此外，也利用此最佳化條件比較含不同胺基官能基之短隧道 SBA-15 (10%NH2-Zr-SBA-15-at 與 10%dia-Zr-SBA-15-at) 作為觸媒在相同條件下反應，分別得到 31% 及 11% 的產率，顯示不同胺基官能基的鹼性強度會影響催化活性。然而，將未進行鹼處理的上述兩種胺基官能基 SBA-15 作為觸媒進行反應，則可以得到 分別為 49% 及 52% 之較高產率，由以上實驗結果可證實材料中胺基官能基的鹼性以及未經鹼處理存在之氯離子為觸媒活性的關鍵。

關鍵字

二氧化碳 ； SBA-15 ； 環加成反應 ； 碳酸鹽 ； 環氧化物

並列摘要

Carbon dioxide is one of the primary greenhouse gases which cause climate change in the past few years. Up to now, various strategies for reducing CO2 have been developed, such as carbon capture and storage. However, chemical fixation of CO2 to generate useful chemicals is a superior option. In this work, short-channel SBA-15 materials were functionalized with various amino groups, including propylamine (NH2), diamine (dia), and guanidine (gua) though one-pot method. The resultant materials were characterized by XRD, N2 sorption isotherm, TGA, SEM, EDS, FT-IR, and Solid NMR. The reaction condition of catalytic cycloaddition of CO2 to 1,2-butylene oxide was optimized by changing the reaction temperature, catalyst loading, and the CO2/epoxide ratio. The optimal yield of cyclic carbonates (1,2-butylene carbonate) determined by GC-FID was ca. 71% over 10% guanidine-functionalized SBA-15 (10%gua-Zr-SBA-15-at) at 140 °C for 18 h with CO2/epoxide ratio of 3.2. In the same condition, 48% yield of cyclic carbonate was obtained over rod 10%gua-r-SBA-15-at, implying the short channels would facilitate the diffusion of reactants into the pores of SBA-15 and access the catalytic active sites. On the other hand, the yields were only ca. 31% and 11% over 10%NH2-Zr-SBA-15-at and 10%dia-Zr-SBA-15-at, respectively, under the same reaction condition, inferring the basicity of amino-group would affect the catalytic activity. However, the yields increased to ca. 49% and 52%, respectively, over the latter amino-functional catalysts without alkaline treatment (deprotonation step). These results imply that the catalytic activity in CO2 cycloaddition to epoxide is not only related to the basicity of amino-group but also the presence of chloride counter anions on the catalyst.

並列關鍵字

CO2 ； fixation ； SBA-15 ； cycloaddition ； carbonate

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