| 摘要: | 醇類在許多化學反應中是極為重要的化學材料，可廣泛用於工業中，而銅系觸媒近年來也因為高選擇性及高轉化率獲得很大的關注。本研究旨在開發一個己二酸二甲酯氫解成己二醇及己二酸二甲酯氫解成 1,6-己二醇的酯氫解的異相觸媒，研究的方法是先根據文獻資料篩選一些具潛力的觸媒及促進劑，實際進行觸媒的合成，並測試各合成觸媒的活性，探討促進劑的效應，所合成的觸媒並以 XRD, TEM, HRTEM,ASAP 等儀器鑑定，以瞭解所合成觸媒的性質及影響觸媒活性的原因。Cu-Mn-Al 觸媒含有高成分
的銅，具有特殊的微觀結構，氧化物觸媒於 190-230℃的溫度下用稀釋的氫氣活化，氧化銅將完全還原成銅，並均勻分散在 MnO2/Al2O3 中，可合成奈米級的銅觸媒顆粒，用於很多氫化及氫解反應，具高活性、高選擇性及高的壽命。在多種可能的材料中，選擇錳是因為它產生的副產物少、無毒、弱路易士酸以及錳和己二酸二甲酯的氫解反應速率高。在本研究中，使用了共沉澱法，測試不同的製備方法，發現鈉離子的殘留會嚴重影響反應的轉化率及選擇率，其中 Na2CO3 加入 Cu-Mn-Al 混合溶液進行共沉澱的製備方法，能在水洗的步驟中，最輕易的將鈉離子的含量降低，且水洗的方式必須將沉澱後的濾餅加水，利用磁石攪拌器來攪拌均勻，才能充分的降低鈉離子含量。最佳的觸媒合成方法為 pH 值控制在 9，在 343 K 的溫度下，與 Na2CO3 溶液共沉澱而獲得，於 750K 的溫度下進行燒，此反應在高壓的批式反應器中進行，壓力為 90 kg/cm2，溫度為 220 0C，實驗的最佳條件 Cu/Mn/Al 的重量比為 64.3/15/20.7、pH 值為九且鍛燒溫度為 7500C，在此條件下，得到最佳的轉化率為 94.5%且選擇率也高達 92.9%。;This study was to develop a heterogeneous Cu-based catalyst for the hydrogenation of dimethyl adipate (DMA) to hexanediol (HDO). In the past decades, copper-based catalyst has attracted much attention due to its high activity and selectivity in the gas-phase hydrogenation
of esters. In this research, first select some potential catalysts and accelerators based on
literature information, and actually carry out the synthesis of the catalyst. Test the activity of
each synthetic catalyst, and discuss the effect of the accelerator. The catalysts were prepared by
co-precipitation method under different conditions. XRD, TEM, HRTEM, ASAP analysis were
used to characterize the catalyst. Of a wide variety of possible material, manganese is chosen
because it is less by-product produced, toxic-free, weak Lewis acid and high reaction rate of
hydrogenolysis of dimethyl adipate. The Cu-Mn-Al catalyst contains high-content copper and
has a special microstructure. The oxide catalyst is activated with diluted hydrogen gas at a
temperature of 190-230 °C. The copper oxide will be completely reduced to copper and evenly
dispersed in MnO2/Al2O3, which can synthesize nano-level copper catalyst particles and can be
used in many hydrogenation and hydrogenolysis methods. It has with high activity, high
selectivity .The reactions were carried out in a high pressure batch reactor under 90 kg/cm2
and
220 0C. The following preparation parameters were studied: Cu/Mn/Al weight ratios, pH value,
aging time, and calcination temperature. It was found that the catalyst prepared with Cu/Mn/Al
weight ratios 64.3/10/25.7, pH value of 9, and calcination temperature of 750 oC had the highest
conversion rate of 91.3% and the highest hexanediols selectivity of 89.8% among all catalysts. |
