| 摘要 |
Isophorone is prepared by distilling acetone and a solution of an alkali in a pressure distillation column under a pressure such that the reaction is maintained at 150 DEG C. to 250 DEG C., the acetone being fed into the column at a point below the point of feed of the alkali solution to define a reaction space in the column between said points so that the acetone and alkali react in counterflow to cause condensation of the acetone and so that separation of the acetone and the solvent of the alkali solution occurs above said reaction space and purification of the less volatile condensation products occurs below said reaction space. The solvent for the alkali is water, an aliphatic alcohol or mixtures thereof and the quantities of acetone, alkali and solvent may be matched such that a homogeneous phase is obtained within the reaction space. Isophorone may be isolated from the system by withdrawal and distillation of the organic phase collected in the sump of the distillation column. In the example acetone is fed via pipe 4 into a distillation column 1 having a temperature gradient from 200 DEG C. at the top of the column to 231 DEG C. <PICT:1003570/C2/1> in the sump, maintained by heating the sump 2 with heater 6, which may be used in conjunction with the steam generator 3, and the appropriate column pressure. The aqueous alkali enters through pipe 9 and reacts with the acetone in the space b, the unreacted acetone returning to the column in part via pipe 7 to inlet 4 and in part via the direct return pipe 11 whilst the isophorane is partially purified in space c before collection in the sump. The sump liquid separates into an organic layer, which is removed by pump 10 to be subsequently distilled to yield pure isophorane, and an aqueous phase, which is recycled to inlet 9. |
