原位法制备磷钨酸／SBA-15催化剂及其催化性能

Preparation of 12-Tungstophosphoric Acid/SBA-15 Catalyst by In-situ Method and Its Catalytic Performance

用原位合成法制备了不同固载量的磷钨酸催化剂HPW/SBA-15,通过FTIR、TEM、XRD、31PNMR及N2-吸附脱附等方法对催化剂进行表征。结果表明,在低固载量时,原位法制备的催化剂保持了SBA-15材料的长程有序结构,并且随着固载量的提高,孔径、比表面积等均有所下降;固载量达到33.3%时,SBA-15材料的长程有序结构遭到一定的破坏;在载体孔壁中高度分散的磷钨酸仍然保持了Keggin特征结构,且与SBA-15材料的表面羟基存在一定的化学相互作用。对苹果酯合成的催化性能研究表明,乙酰乙酸乙酯的转化率可以达到87%以上,催化剂使用6次后,催化活性仍保持在85%。

The catalysts of 12-tungstophosphoric acid/SBA- 15 with different loading capacity were prepared by in-situ method. The structure and properties of the catalysts were characterized by means of FTIR spectroscopy, TEM, X-ray diffraction,31 PNMR and N2 adsorption-desorption. The results show that, when the loading capacity was within the lower range, the catalysts retained the long range order structure of the SBA - 15 material. With the increase of loading capacity, the aperture and specific surface area decreased with the increase of loading capacity, However, the structure of SBA - 15 was destroyed in some degree when the loading capacity was up to 33.3%. The 12-tungstophoaphoric acid highly dispersed in the hole of SBA - 15 still kept the Keggin structure, and had certain chemical interaction with the surface hydroxy of SBA - 15. The catalytic properties in the synthesis of fructone show that HPW/SBA- 15 catalyst has high catalytic activity and selectivity, and shows excellent reusability.