| 摘要 |
1,133,510. Autocondensation of acetone. SHAWINIGAN CHEMICALS Ltd. 19 Dec., 1966 [27 Dec., 1965], No. 56656/66. Heading C2C. Condensation products of acetone, e.g. diacetone alcohol, isophorone and mesityl oxide are obtained by mechanically dispersing an acetone immiscible aqueous solution of an alkali metal hydroxide in liquid acetone to form a reaction mixture of a stable fine dispersion of the catalyst in the acetone, and subsequently maintaining the dispersion at appropriate reaction temperatures for the time necessary for the desired autocondensation. Suitably acetone is condensed in the presence of the finely dispersed alkali metal hydroxide catalyst for between 5 minutes and 5 hours, to give as the principal product (a) diacetone alcohol at - 20‹ to 50‹ C., (b) mesityl oxide at 60‹ to 120‹ C. and (c) isophorone at 130‹ to 235‹ C. The catalyst may be an aqueous solution containing 25 to 50% by weight of an alkali metal hydroxide dispersed in acetone so that the mixture contains between 0À001 and 0À5% of alkali metal hydroxide. The catalyst may be dispersed in acetone (a) by passing the liquids together through a constriction which creates a pressure drop of from 20 to 200 lb./in.<SP>-2</SP>, (b) by using an ultrasonic generator or (c) by using a centrifugal pump. |
