摘要
以不同孔径的高比表面积介孔SiO_2为载体,通过浸渍法制备VPO/SiO_2-x(x=6、8、10、12,平均孔径)催化剂。采用BET、XRD、XPS和NH_3-TPD对催化剂进行表征,并考察了其对甲醛-乙酸多相催化制丙烯酸的催化性能。结果表明,不同孔径VPO/SiO_2催化剂均具有较高的比表面积(>180m^2/g)和发达的介孔结构,其平均孔径分别为6.5nm、8.7nm、10.6nm和13.0nm;VPO/SiO_2上丙烯酸的催化选择性由于受催化剂孔径的影响依次为VPO/SiO_2-10>VPO/SiO_2-12>VPO/SiO_2-8>VPO/SiO_2-6。反应温度为350℃时,孔径为10.6nm的VPO/SiO_2上丙烯酸的选择性和收率分别达到76.8%和47.1%,甲醛转化率为61.2%。
The VPO/SiO_2-x(=6,8,10,12,average pore size)catalysts are prepared by impregnation methods using high specific surface area SiO_2 with different pore size as supports.The catalysts are characterized by BET, XRD, XPS and NH_3-TPD, and also investigated by heterogeneous catalysis of aldol condensation of acetic acid with formaldehyde to produce acrylic acid.The results show that all catalysts have higher specific surface area(>180 m^2/g)and well-developed mesoporous structure,but with average pore size of 6.5 nm,8.7 nm,10.6 nm and 13.0 nm,respectively.The acrylic acid selectivity over the prepared VPO/SiO_2-x catalysts follow the order of VPO/SiO_2-10 > VPO/SiO_2-12 > VPO/SiO_2-8 > VPO/SiO_2-6. The catalytic conversion of formaldehyde over VPO/SiO_2-10(average pore size is 10.6 nm)reaches 61.2% when the reaction temperature is 350 ℃,with acrylic acid selectivity and yield of 76.8% and 47.1% respectively.
出处
《石油与天然气化工》
CAS
北大核心
2018年第1期41-45,59,共6页
Chemical engineering of oil & gas
关键词
V-P氧化物
丙烯酸
甲醛
乙酸
羟醛缩合
V-P oxides
acrylic acid
formaldehyde
acetic acid
aldol condensation
