| 摘要 |
PURPOSE:To improve the selectivity of the objective compound in the synthesis of dimethylamine from ammonia and methanol in vapor phase using a specific zeolite as a catalyst, by contacting said catalyst with a steam-containing atmosphere at a specific temperature prior to the reaction. CONSTITUTION:Dimethylamine useful as a solvent and raw material of pharmaceuticals, etc. is synthesized by the vapor-phase reaction of ammonia with methanol in the presence of a catalyst comprising a zeolite selected from mordenite, clinoptilolite and erionite. In the above reaction, the used or fresh catalyst is made to contact, prior to the reaction, with a steam-containing atmosphere at 350-500 deg.C, especially 380-500 deg.C for 1-400hr, preferably 10-30hr, especially 15-25hr, under the steam pressure of preferably 1-70atm, especially 10-30atm, specifically 10-20atm at 250-700 deg.C. The selectivity of the objective compound can be improved remarkably by this process without causing a large loss in the catalytic activity.
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