α-MoO_(3)的结构形貌与其催化合成季戊四醇正辛酸酯的构效关系研究

The Structural Morphology of α-MoO_(3) and its Structure-activity Relationship for Catalytic Production of Pentaerythritol n-Octanoate Ester

通过溶胶-凝胶法制备一种用于季戊四醇(PER)和正辛酸(OTA)酯化合成季戊四醇正辛酸酯(POE)的α-MoO_(3)催化剂.采用XRD、SEM、XPS和FITR分析手段对α-MoO_(3)粉体进行了表征.结果表明,焙烧温度对α-MoO_(3)的晶相结构、表观形貌及催化性能的影响显著.当焙烧温度达到450℃时,催化剂为正交晶面结构(021)和(110)同时择优取向的α-MoO_(3),样品表面光洁平整、大小均匀、分散性好,同时表现出较高的催化活性.在适宜的反应条件下(T=200℃, t=4 h,酸醇摩尔比n(OTA)∶n(PER)=4.0∶1,催化剂用量n(α-MoO_(3)-450)∶n(PER)=0.005),PER转化率可达98.8%, POE的选择性可达100%.

Molybdenum trioxide(MoO_(3))catalyst,which was used for esterification of pentaerythritol(PER)and n-octanoate acid(OTA)to pentaerythritol n-octanoate ester(POE),was prepared by sol-gel method.The α-MoO_(3) catalyst was produced using the sol-gel technique and temperature control.The structure and morphology of the samples were characterized by XRD,SEM,XPS and FITR.The results showed that calcination temperature had significant influence on crystalline structure,apparent morphology and catalytic properties ofα-MoO_(3).When the calcination temperature is 450°C,α-MoO_(3) with preferred orientation of(021)and(110)crystal planes.Theα-MoO_(3) powder has smooth surface,uniform size and good dispersion and exhibits high catalytic activity.When esterification reaction was carried out at 200℃,the molar ratio of n-octanoate to pentaerythritol(n(OTA)/n(PER))of 4,reaction time of 4 h,and n(α-MoO_(3)-450)/n(PER)of 0.005,the conversion of PER can be 98.8%,and the selectivity of pentaerythritol n-octanoate ester is 100%.