金屬/非金屬改質石墨型氮化碳應用於甘油與二氧化碳之羧化反應

隨著科技發展越來越發達，對能源的需求也逐漸提升，而人們也在各個方面依賴著能源，這也使能源問題逐漸被重視，目前生質柴油是備受重視的再利用能源，但副產物甘油也隨之而生，甘油價格也隨產量上升而降低，因此過剩的甘油也變相造成環境的負擔，而文明發展也產生出許多溫室氣體，例如二氧化碳，進而造成全球暖化的問題，甘油及二氧化碳兩者都對地球有負面影響，因此本實驗利用觸媒將兩者汙染物進行催化反應。本研究利用熱聚合法製備出低成本及高穩定性的石墨型氮化碳材料(g-C3N4)，再摻雜不同非金屬( P, S )與金屬離子( La )，進而改變材料形貌，使PSCN成功形成較不規則的顆粒形狀，有別於一般石墨型氮化碳的層狀結構，並應用於甘油與二氧化碳的羧化反應，藉由改變實驗條件找出最佳反應條件後，加入5 mL乙腈作為脫水劑，與先前條件相比可以有效地提升轉化率，CN、PSCN及10LaPSCN的轉化率分別成功從29.1%、52.9%及45.2%提升至61.6%、84.7及66.5%，並將材料進行重複性實驗，得知進行三次重複性的PSCN雖然因為重量損失及反應後的影響轉化率有些微下降，但依然維持良好的轉化率，而PSCN擁有最高轉化率則是歸功於在適當環境下得以突破此反應的限制，且因其表面粗糙度較高使反應物與材料有更高的接觸機會，因此有最好的催化效果，本研究製備之石墨型氮化碳可有效用於甘油與二氧化碳的反應中，以解決生產生質柴油所間接造成之環境汙染。

關鍵字

甘油；二氧化碳；乙腈；甘油碳酸酯；羧化反應

並列摘要

With the development of science and technology more and more developed, the demand for energy is also gradually rising. People are also dependent on energy in all aspects, which has made the energy issue more important. At present, biodiesel is a highly valued energy for reuse, but the by-product glycerol is also produced. The price of glycerol also decrease with the increase in production. Therefore, the excess glycerol also cause burden on the environment. And the development of civilization also produce many greenhouse gases, such as carbon dioxide, which is cause the problem of global warming. Both glycerol and carbon dioxide have a negative impact on the earth. Therefore, this work use catalysts to catalyze the two pollutants. In this study, a low-cost and high-stability graphitic carbon nitride material ( g-C3N4 ) was prepared by thermal polymerization method. Doped with different non-metals ( P, S ) and metal ions ( La ), and change the morphology of the material. Make PSCN successfully form a relatively irregular particle, which is different from the layer structure of general graphitic carbon nitride, and used in the carboxylation reaction of glycerol and carbon dioxide. After finding the best reaction conditions by changing the experiment conditions, and adding 5 mL of acetonitrile as a dehydrating agent can effectively increase the conversion compared with the previous conditions. The conversion of CN, PSCN and 10LaPSCN have been successfully increased from 29.1%, 52.9% and 45.2% to 61.6%, 84.7 and 66.5% respectively. The material was subjected to cycle experiments, and it was learned that although the conversion of PSCN was slightly decreased due to the weight loss and the effect of the reaction after three cycle tests, it still maintained a excellent conversion. PSCN has the highest conversion due to its ability to break the limits of this reaction under the right environment. And because of its higher surface roughness, the reactant has a higher chance of contact with the material, so it has the best catalytic effect. The graphitic carbon nitride prepared in this study can be effectively used in the reaction of glycerol and carbon dioxide to solve the indirect environmental pollution caused by the production of biodiesel.