氧化钴催化剂的制备及其在乙苯氧化中的应用

Synthesis and Application in Ethylbenzene Oxidation of Cobalt Oxide Catalyst

以乙酸钴为原料,采用高温煅烧法制备氧化钴催化剂,并通过热重(TGA)、X射线多晶粉末衍射分析(XRD)、X射线光电子能谱(XPS)、BET比表面积测试(BET)和高分辨透射电子显微镜(HRTEM)等对样品进行表征分析,确认该样品是CoO和Co3O4两种物质的混合物,具有中孔、大孔为主的多孔结构。然后,以乙苯为原料,在空气中进行催化氧化反应,重点考查了所制备的氧化钴催化剂的性能,产物则是通过气相色谱仪(GC)检测分析。在该体系下,研究了反应温度、反应时间、催化剂等单因素,并分析得到了反应的最佳工艺条件。结果表明:在反应温度为130℃,反应时间为24 h,催化剂用量为3wt%时,乙苯的转化率可以达到38.81%,苯乙酮选择性可以达到88.56%。相对于传统的醋酸钴,所制备的氧化钴催化剂展现出了高效、不易被氧化、能循环使用等诸多优势,具有较好的应用前景。

Cobalt oxide catalyst was prepared from cobalt acetate by high temperature calcination with cobalt acetate as raw material.The sample was characterized and analyzed by thermogravimetry(TGA),X-ray diffraction(XRD),Xray photoelectron spectroscopy(XPS),N2adsorption desorption experiment(BET)and high resolution transmission electron microscope(HRTEM).The results show that the calcined catalyst is composed of CoO and Co3O4,and it possesses porous structure dominated by mesopores and macropores.Then,with the sample as catalyst and ethylbenzene as raw material,the catalytic oxidation reaction was carried out in air,and the product was detected and analyzed by gas chromatograph(GC).In this system,the reaction temperature,reaction time and catalyst dosage were studied,and the optimum reaction conditions were obtained.The results show that when the reaction temperature is 130℃,the reaction time is 24 h,the molar amount of catalyst is 3%,the conversion of ethylbenzene can reach 38.81%,and the selectivity of acetophenone can reach 88.56%.Compared with the traditional cobalt acetate,the cobalt oxide catalyst prepared in this experiment shows many advantages,such as high efficiency,non-oxidization,recyclability and so on.