高活性隐钾锰矿分子筛K-OMS-2的制备及其催化氧化苯甲醇制苯甲醛反应性能的研究

采用醋酸丁酯处理后固相合成的方法制备了一种隐钾锰矿分子筛催化剂K-OMS-2。相对于传统固相法制备的样品,此法所制备催化剂的比表面积略有下降,但孔容和孔径明显增大,其原因可能是在焙烧过程中醋酸丁酯的挥发分解形成了造孔效应。在苯甲醇选择性氧化制苯甲醛反应中,所制备K-OMS-2催化剂的活性相对传统固相法制备的样品有显著提高。经413 K合成、433 K焙烧的催化剂反应转化率达到79.6%,苯甲醛选择性维持在100%。催化剂活性提高的主要原因可能是催化剂较大的孔容、孔径促进了苯甲醇氧化反应中分子的扩散效率,因而提高了总体催化反应速率。

Preparation of Cryptomelane Octahedral K-OMS-2 Catalyst and Its Application in the Oxidation of Benzyl Alcohol

A kind of cryptomelane octahedral molecular sieves K-OMS-2 was synthesized by a modified solid-state reaction method,in which the precursors were pretreated by the butyl acetate before solid-state reaction.Comparing with the conventional solid-state reaction derived sample,the obtained catalyst has larger pore volume and pore diameter,while its surface area shows a slight decrease.For the oxidation of benzyl alcohol,the prepared K-OMS-2 shows much higher catalytic activity than that of the conventional solid-state reaction derived sample.The reason may be attributed that the large pore of the catalyst promotes the diffusion efficiency of reactants and products.