| 摘要 |
1,205,913. Paraldehyde. MELLE-BEZONS. 11 June, 1969 [2 Aug., 1968], No. 29700/69. Heading C2C. Paraldehyde is produced by continuously passing a stream of liquid acetaldehyde upwards through a bed of a cation exchanger in acid form, e.g. a poly-styrene sulphonic resin in the " hydrogen form," contained in a reactor which is vertical or substantially vertical and has the shape of an inverted cone or frustum, the acid cation exchanger being maintained in a dispersed and fluidized state in and by the liquid acetaldehyde stream. The reaction may be carried out at a temperature in the range 25‹ to 45‹ C. and a pressure of 1 to 3 kg/cm<SP>2</SP>, preferably in the presence of 1 to 5% by weight of water. Paraldehyde is recovered by rectification from the mixture of paraldehyde and high-boiling by-products remaining after unconverted acetaldehyde, lowboiling impurities and water, if present, have been removed through distillation. |
