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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_2CO_3,Na_2MoO_4,或Na_xLi_(1-x)AlO_2(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。
Methanol dehydrogenation in anaerobic conditions, can produce very low levels of formaldehyde. In the above reaction, a supported oxide catalyst supported on silica gel is mainly used, and metals of Group IB and Group IIB of the periodic table such as copper, silver or zinc are the main components. Oxides of these metals are easily reduced at high temperatures, sintered and surface charred to deactivate the catalyst. Addition of P, S, Se or Te as a cocatalyst can improve the catalytic performance to a certain extent. Recent developments have tended to use unsupported alkali metal salts as catalysts such as Na_2CO_3, Na_2MoO_4, or Na_xLi_ (1-x) AlO_2 (0≤x≤1). Such catalysts require excessively high reaction temperatures, such as above 650 ° C, or even 900 ° C.