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利用直接焙烧法在400℃焙烧(NH4)6MoO7O24.4H2O制备了碳酸二甲酯(DMC)与乙酸苯酯(PA)酯交换合成碳酸二苯酯(DPC)反应的正交晶系MoO3催化剂,通过比表面积(BET)、X射线衍射(XRD)、X射线光电子能谱(XPS)、傅立叶变换红外光谱(FT-IR)、扫描电镜(SEM)等技术,对MoO3催化剂在失活前后的结构和形貌进行了分析,探讨了MoO3催化剂的失活行为.结果表明,正交晶系MoO3的(021)、(110)晶面有利于酯交换反应,多次使用后,催化剂表面有无定形碳的物理沉积,催化剂比表面积降低,催化剂颗粒长径比发生了改变,催化剂(021)、(110)晶面衍射峰强度减弱,进而导致了MoO3催化剂的失活.
The orthorhombic MoO3 catalyst for transesterification of diphenyl carbonate (DPC) with dimethyl carbonate (DMC) and phenyl acetate (PA) was prepared by direct calcination of (NH4) 6MoO7O24.4H2O at 400 ℃. BET surface area (BET), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) (021) and (110) planes of the orthorhombic MoO3 are favorable for the transesterification reaction. After repeated use, the catalyst surface has amorphous carbon , The specific surface area of the catalyst decreases, and the aspect ratio of the catalyst particles changes. The diffraction peak intensities of the (021) and (110) planes decrease, which leads to the deactivation of the MoO3 catalyst.