Fluorination of dichlorodifluoromethane to synthesize tetrafluoromethane over Cr2O3–AlF3 catalyst
Fluorination of dichlorodifluoromethane to synthesize tetrafluoromethane over Cr2O3–AlF3 catalyst
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DOI：
10.1016/j.jiec.2011.05.005
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发表时间：
2011-05
影响因子：
6.1
通讯作者：
Wenzhi Jia;Ling-yun Jin;Yue-juan Wang;Jiqing Lu;M. Luo
中科院分区：
文献类型：
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作者：
Wenzhi Jia;Ling-yun Jin;Yue-juan Wang;Jiqing Lu;M. Luo
以二氯二氟甲烷(CCl2F2)为原料，采用沉积-沉淀法制备了一系列不同Cr2O3量的Cr2O3AlF3催化剂，以合成四氟甲烷(CF4)。当Cr2O3wt.%为61.2wt.%时，催化剂的活性最高，400℃时CF4的产率为94%。X射线衍射和拉曼光谱结果表明，催化剂中存在大量的Cr2O3相和α-AlF3相。氨程序升温脱附(NH3-TPD)和吡啶化学吸附的傅里叶变换红外光谱(FTIR)表明催化剂具有较强的Lewis酸性。Cr2O3AlF3催化剂中的铬物种和Lewis酸分别是CCl2F2氟化和歧化反应的活性中心。这表明Cr2O3-AlF3催化剂对氟化和歧化反应具有双功能催化性能。
A series of Cr2O3–AlF3catalysts with different Cr2O3contents were prepared by a deposition–precipitation method for the fluorination of dichlorodifluoromethane (CCl2F2) to synthesize tetrafluoromethane (CF4). The highest activity was obtained on the Cr2O3–AlF3catalyst containing 61.2wt.% of Cr2O3, with the CF4yield of 94% at 400°C. X-ray diffraction (XRD) and Raman spectroscopy results indicated the presence of bulk Cr2O3and α-AlF3phases in the catalysts. Ammonia temperature programmed desorption (NH3-TPD) and Fourier transformation infrared spectroscopy (FTIR) of pyridine chemisorption revealed strong Lewis acidity of the catalysts. The Cr species and Lewis acid in the Cr2O3–AlF3catalysts were the active sites of fluorination and dismutation reaction of CCl2F2, respectively. This indicated bi-function catalytic performance of Cr2O3–AlF3catalysts for fluorination and dismutation reaction.