隨著科技逐漸發展，人們對於能源的需求也日益增加，其中石化燃料的大量使用，造成了能源逐漸缺少，以及環境汙染、氣候變遷等問題。因此，這促使各國積極開發乾淨、可再生的替代燃料，在這之中以生質柴油最受矚目，因為此為一種無毒、可生物分解、可再生的替代能源。
生質柴油一般是透過動、植物油脂經轉酯化反應合成，並在觸媒的催化下以加速反應進行，其中因非均相鹼性觸媒具有可重複使用、易於分離等特點而被研究者廣泛使用。然而，在實際反應中，非均相觸媒會遭遇到溶出問題，使得觸媒重複使用性不佳，因此本實驗將著重在研究溶出行為，希望能找出抑制觸媒溶出的關鍵因素。
本研究以廣泛使用的氧化鈣觸媒做為研究對象，採用固態燒結法製備氧化鈣塊材以供觀察，並使用甲醇、甲醇甘油混合液以模擬在轉酯化反應前、後期的溶出行為。研究中使用SEM/EBSD技術，以得到表面結晶取向分布與溶出形貌的關聯性，相較於以往利用單晶試片觀察表面變化，此研究提供了較為簡便，且能觀察到許多高指數晶面反應行為的實驗方式。
研究結果顯示，表面溶出行為與表面結晶取向有很大的關聯性。在轉酯化反應前期 (甲醇溶液)，接近{001}方向的晶面會產生變化而導致溶出，而接近{111}方向之晶面則因無明顯變化，代表較具有抗溶出特性；轉酯化反應後期 (甲醇甘油溶液)，也可觀察到同樣的溶出趨勢，說明了在整體轉酯化反應中，相較於其餘晶面，接近{111}方向之晶面最為穩定。

Biodiesel is a non-toxic, biodegradable, renewable energy resource which is produced by transesterification of vegetable oils or animal fats with methanol. To facilitate transesterification reaction, different kinds of heterogeneous base catalysts have been developed. However, these catalysts were deactivated after several reaction runs due to severe catalyst leaching. To cope with this issue, we investigated the leaching behavior on calcium oxide catalyst surface for better understanding in leaching phenomenon. In this study, SEM/EBSD technique was used to correlate the surface leaching behavior with surface crystal orientation, and methanol and methanol-glycerol solution were used to simulate the early/final stage of transesterification environment respectively. The results showed that leaching behavior were strongly dependent on the surface crystal orientation. In the transesterification reaction, the near {001} orientations are the most reactive surfaces which can cause catalyst leaching, and in contrary the near {111} orientations are the most stable surfaces and showed a negligible leaching into the solution.

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