AlP_xO催化剂的制备、表征及其在邻苯二酚O-单醚化反应中的催化性能

Preparation and Characterization of AlP-xO Catalysts and Their Catalytic Properties for the Vapour-phase O-Methylation of Catechol

采用沉淀法制备了AlPxO(x=0,0.33,0.5,1.0,1.5,2.0)催化剂,通过XRD,FTIR,固体核磁共振,BET,NH3-TPD和CO2-TPD等手段对催化剂进行了表征,发现n(P)/n(Al)对催化剂结构及表面酸碱性质有很大影响.考察了AlPxO催化剂上以邻苯二酚和甲醇为原料,采用气相法一步合成愈创木酚的反应性能,并研究了催化剂表面酸碱性质对反应活性和选择性的影响.结果表明,催化剂表面同时存在一定量的弱酸和弱碱中心有利于提高愈创木酚的收率.

AlPxO（x=0, 0.33, 0. 5, 1.0, 1.5, 2.0） catalysts were prepared via precipitation method and characterized by means of XRD, FTIR, solid-state MAS NMR, N2 adsorption, NH3-TPD and CO2-TPD techniques. The morphology of the catalysts changes from amorphism to crystalline with the increase of n（P）/n（Al）. Both the acidic and basic amouhts on the catalysts surface increase first with the increase of P contents [n（P）/n（Al）≤0. 5], and then decrease dramatically with further increasing P contents. Meanwhile, vapor-phase O-methylation of catechol with methanol was investigated over various AlPxO catalysts. Among them, AlP1.0O sample exhibits a good catalytic activity and selectivity to guaiacol, which resulted in the highest yield of guaiacol. This may mainly be attributed to the presence of suitable amounts of weak acid and base sites on the surface of the catalyst.