摘要
甲醇在无氧条件下脱氢,可以制得含水量极低的甲醛。在上述反应中,主要采用以硅胶为载体的负载型氧化物催化剂,其中以周期表ⅠB和ⅡB族金属,如铜、银或锌为主要组分。这些金属的氧化物在高温下易还原、烧结和表面积炭而使催化剂失活。添加P,S,Se或Te等组分作为助催化剂,在一定程度上可以改善催化性能。最近的发展倾向是采用非负载的碱金属盐作为催化剂,如Na<sub>2</sub>CO<sub>3</sub>,Na<sub>2</sub>MoO<sub>4</sub>,或Na<sub>x</sub>Li<sub>1-x</sub>AlO<sub>2</sub>（0≤x≤1）。这类催化剂要求过高的反应温度,如高于650℃,甚至900℃条件下使用。
Novel catalysts of higher selectivity for the dehydrogenalion of me-thanol to formaldehyde were obtained by supporting hardly reducible metal oxide such as zirconia or alumina on silica. The ZrO2/SiO2 and Al2O3/SiO2 catalysts were prepared by impregnation of SiO2 with aqueous solution of zirconium nitrate and aluminium nitrate respectively. The selectivity for the formation of formaldehyde of 2% ZrO2/SiO2 and 0.9% Al2O3/SiO2 was the highest. The catalyst containing 2.0% Zr was characterized by X-ray diffraction, NH3-TPD and XPS. The nature of the active sites for methanol conversion on supported oxide catalyst and the reaction mechanism were also discussed.
基金
福建省自然科学基金
关键词
甲醇
脱氢
甲醛
氧化锆催化剂
Supported catalyst,ZrO2/SiO2,meth.anol,dchydiogenation,formaldehyde
