Cu/ZnO催化糠醛气相加氢制2-甲基呋喃的研究

通过共沉淀法制备一系列铜锌催化剂,用于固定床上糠醛气相加氢制2-甲基呋喃的研究。采用X射线衍射仪(XRD)、N_2吸附-脱附、扫描电子显微镜(SEM)、H_2-程序升温还原(H_2-TPR)、NH_3-程序升温脱附(NH_3-TPD)表征,分析催化剂中Cu0和ZnO在催化反应中的作用。结果表明,Cu~0是糠醛加氢的活性中心,氧化锌的加入减小了催化剂晶粒粒径、增大了催化剂比表面积、利于催化剂还原和增加催化剂表面弱酸性位。当Cu/Zn物质的量比为1∶2时,Cu_1Zn_2催化剂具有适宜氧化还原活性中心及弱酸位数量,对2-甲基呋喃表现出较高的选择性。Cu_1Zn_2催化剂在常压、反应温度为200℃、氢醛物质的量比为4∶1、糠醛体积空速为0.3 h-1条件下,糠醛转化率100.0%,2-甲基呋喃选择性最高为93.6%。反应稳定运行200 h后,糠醛转化率仍为100.0%,2-甲基呋喃选择性为80.0%,糠醇选择性为11.4%。

Study on the vapor phase hydrogenation of furfural to 2-methylfuran on Cu/ZnO catalyst

A series of Cu/ZnO catalysts were prepared by using co-precipitation method and their performance for the furfural gas phase hydrogenation to 2-methylfuran was investigated in a fixed bed reactor. The catalysts were characterized by X-ray diffraction (XRD), N₂ adsorption desorption, H₂ temperature programmed reduction (H₂-TPR), scanning electron microscope (SEM) and NH₃-temperature programmed desorption (NH₃-TPD) techniques to analyze the roles of Cu⁰ and ZnO. The results showed that Cu⁰ was the active center for the furfural hydrogenation and the addition of ZnO in Cu catalysts can reduce the crystal size, enhance the surface area, improve the reduction and increase the surface acidity of the catalysts. When the molar ratio of Cu/Zn molar ratio is 1:2, Cu₁Zn₂ catalyst showed the highest selectivity to 2-methylfuran due to its suitable numbers of redox active centers and weak acidic sites. Under the atmospheric pressure, reaction temperature of 200℃, 4:1 molar ratio of hydrogen to furfural and furfural volume space velocity of 0.3 h^-1, the conversion of furfural reached almost 100.0% with 93.6% selectivity to 2-methylfuran over Cu₁Zn₂ catalyst.