以Pd+Pt/SBA-15 觸媒及氫氣在超臨界二氧化碳中還原多溴二苯醚之探討

Hydrodebromination of Polybrominated Diphenyl Ethers by Pd+Pt/SBA-15 with Hydrogen Gas in Supercritical Carbon Dioxide

陳偉銘(Wei-ming Chen)

指導教授 ： 葉華光

中原大學/理學院/化學研究所/碩士(2012年)

https://doi.org/10.6840/cycu201200654

摘要

本研究目的在以超臨界二氧化碳為媒介下，使用不同金屬比例之含鈀與鉑的中孔洞材料為觸媒，在不同的溫度下，探討降解多溴二苯醚的能力。
在觸媒的製備上使用初濕含浸法，製備不同金屬比例之Pd+Pt/SBA-15，以此可回收之觸媒作為在超臨界二氧化碳中進行多溴二苯醚同類物(BDE#3)的脫溴氫化反應。
在初濕含浸法的操作上，依所需金屬之比例取不同克數的Pd(NH3)4(NO3)2 10 wt %溶液與Pt(NH3)4(NO3)2粉末金屬前驅物，緩慢的加入SBA-15擔體中，並施以不斷攪拌，在500 °C下鍛燒兩小時，獲得Pd+Pt/SBA-15，並以TEM觀察觸媒金屬分布的狀況。
在無觸媒的情況下，萃取條件為100 atm、200 °C的超臨界二氧化碳中，氫源為氫氣5 atm，有diphenyl ether生成；於320 °C時，反應物(BDE#3)完全降解成diphenyl ether，且在短時間內(5分鐘)即可達成。
以0.2 g金屬觸媒進行BDE#3的氫化脫溴反應，在100 atm超臨界二氧化碳下，依不同溫度與觸媒找尋最佳之反應條件，並在2 % Pd+1 % Pt/SBA-15之觸媒反應中，成功的將BDE#3完全降解成cyclohexane。不同金屬比例之觸媒反應效果也不同，但溫度提高對反應效果有提升之趨勢。

關鍵字

多溴二苯醚 ； 超臨界二氧化碳 ； Pd+Pt/SBA-15

並列摘要

The goal of this study is to prepare a catalyst, Pd+Pt/SBA-15, by the Incipient Wetness Impregnation(IWI)method to be used as a recyclable catalyst for the purpose of hydrodebromination of a PBDE congeners (BDE#3)in the presence of hydrogen gas in scCO2 with different temperatures.
With the IWI method, different weight of Pd(NH3)4(NO3)2 10 wt % and Pt(NH3)4(NO3)2 precursors were added slowly to a SBA-15 template with continual stirring before being calcined at 500 °C for about 2 hrs to obtain different ratios of Pd and Pt in SBA-15. This product was analyzed by TEM for metal distribution.
Without the presence catalyst and with 5 atm hydrogen gas in supercritical carbon dioxide at 100 atm and 200 °C with 60 minute reaction time, BDE#3 was partially reduced to diphenyl ether, and at 320°C the reactant was completely reduced to diphenyl ether.
From the results of hydrodebromination of BDE#3 by 5 atm hydrogen in supercritical carbon dioxide at 100 atm and the reaction time 60 minute with the presence of catalyst at different temperatures, other products such as diphenyl ether, cyclohexanone, and cyclohexane were observed. With a 2 % Pd+1 % Pt/SBA-15, BDE#3 was completely converted to cyclohexane.

並列關鍵字

Pd+Pt/SBA-15 ； supercritical carbon dioxide ； Polybrominated diphenyl ethers (PBDEs)

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