| 摘要 |
Alkali metal methoxides are prepared from aqueous alkali metal hydroxide, which may have been admixed with methanol, and methanol in a reaction column having at least 5, preferably from 15 to 30, theoretical plates between the feed point for the aqueous alkali metal hydroxide and the feed point for the methanol. The gaseous methanol/water mixture formed in the reaction is fractionated in a rectification column. In one variant of the invention, the trays chosen for the reaction column configured as a bubble cap tray, valve tray or sieve tray column are trays in which not more than 5%, preferably <=1%, of the liquid rains through the respective trays. In another variant of the process of the present invention, the double-wall reaction column has a temperature in the double wall which is from 3 to 10° C. above the internal temperature in the column and is provided with random or ordered packing, where the average ratio of liquid flow to vapor flow is not exceeded by more than 15%, preferably not by more than 3%, in all subregions of the column cross section which correspond to more than 2% of the total column cross section. |
