KOAc/NaY催化合成邻甲基苯甲醚

Synthesis of o-Methoxytoluene over KOAc/NaY Catalyst

以NaY分子筛为载体,采用乙酸钾(KOA c)为活性组分通过真空浸渍与微波辐射的方法制备了KOA c/NaY负载型固体碱催化剂(简称催化剂),考察了催化剂对碳酸二甲酯(DMC)与邻甲基苯酚(OC)合成邻甲基苯甲醚(OM)反应的催化性能,采用X射线衍射、N2吸附-脱附和CO2程序升温脱附法对催化剂进行了表征。实验结果表明,真空浸渍有利于KOA c向NaY分子筛的孔内扩散,形成更多的活性中心;微波辐射有利于KOA c在NaY分子筛表面的分散;NaY分子筛负载KOA c后,在表面形成碱性位,且随KOA c负载量的增加催化剂的碱性增强;KOA c负载量为2.00mm ol/g时,催化剂的活性较好,负载量过大会减小催化剂的比表面积和孔体积。在548K、0.6M Pa、气态空速870h-1、以N2为载气、n(N2)∶n(DMC)∶n(OC)=8.6∶1.0∶1.0的条件下,OC转化率高达85.70%,OM选择性高达99.70%。

Synthesis of o-methoxytoluene by vapor phase reaction of o-cresol with dimethyl carbonate over KOAc/NaY catalyst was investigated. The catalyst was prepared by vacuum impregnation and microwave radiation. Impregnation in vacuum could strengthen diffusion of KOAc to interior pores of NaY molecular sieve and microwave radiation could improve dispersion of KOAc on surface of NaY molecular sieve. Basic sites formed when KOAc was loaded on surface of NaY molecular sieve and basicity of catalyst intensified with increase of KOAc loading amount, but pores would be blocked up when loading amount of KOAc was too high. Appropriate loading amount of KOAc was 2.00 mrnol/g. Under optimal reaction conditions： 548 K, 0.6 MPa, GHSV 870 h^-1 and n（N2） ： n（dimethyl carbonate） ： n（o-cresol） =8.6 ： 1.0 ： 1.0,conversion of o-cresol and selectivity to o-methoxytoluene could reach 85.70% and 99.70% ,respectively.