二氧化硅负载磷钨酸催化合成蒽醌

采用等体积浸渍法制备了负载型磷钨酸(HPW)催化剂,将其用于催化邻苯甲酰苯甲酸(BBA)脱水合成蒽醌;采用XRD,FTIR,TG-DTG等手段对SiO_2负载的磷钨酸(HPW/SiO_2)催化剂进行表征;考察了载体种类、焙烧温度、HPW负载量对其催化性能的影响。实验结果表明,制备负载型HPW催化剂的适宜条件为:以SiO_2为载体、焙烧温度250℃、焙烧时间3 h、HPW负载量为30%。HPW/SiO_2催化剂催化合成蒽醌的适宜反应条件为:催化剂与BBA的质量比为1.60、反应温度220℃、反应时间2.0 h,在此条件下,蒽醌收率可达99.6%。HPW/SiO_2催化剂的稳定性较差,BET,UV-Vis,Py-IR表征结果显示,积碳结焦使催化剂B酸酸量减小是催化剂失活的原因。

Synthesis of Anthraquinone over HPW/SiO2 Catalyst

A series of the supported phosphotungstic acid（HPW） catalysts were prepared through an isochoric impregnation method and were used in synthesis of anthraquinone（AQ） through dehydration of o-benzoylbenzoic acid（BBA）,with SiO₂,activated carbon,bentonite orγ-Al₂O₃ as supports.The supported catalyst HPW/SiO₂ was characterized by means of TG-DTG,XRD and FTIR.Effects of the support type,calcination temperature and HPW loading on the catalyst activity were investigated and the catalytic performance of HPW/SiO₂ catalyst in the anthraquinone synthesis was evaluated.The results indicated that under the optimal conditions for the catalyst preparation:SiO₂ as support, calcination temperature 250℃,calcination time 3 h and HPW loading 30%（mass fraction）,and the optimal conditions for the synthesis:m（catalyst）:m（BBA） 1.60,reaction temperature 220℃and reaction time 2 h,the AQ yield could reach 99.6%.But the HPW/SiO₂ catalyst stability in the AQ synthesis was not good.It was found by means of BET,UV-Vis and Py-IR that the catalyst deactivation was due to decrease of the Br（o|¨）nsted acid sites,which was caused by coking on the catalyst surface.