摘要 |
For the manufacture of lactulose, an alkaline aqueous solution of lactose and borax is prepared and heated at a temperature above 80 DEG C. The lactulose is separated from the resulting conversion products. Apart from the borox, no alkalising material is added to the solution. The conversion is carried out at pH 8.3. In order to maintain the sodium ions in the production cycle, the borox may be manufactured in an aqueous solution of boric acid and already simultaneously with the lactose, while the sodium ions are transferred from the solution of the conversion products in the solution of the boric acid by electrodialysis. Alternatively the sodium ions may also be removed from the solution of the conversion products as readily as possible by means of a weakly acid ion exchanger and only thereafter by means of a more strongly acid ion exchanger. The weakly acid ion exchanger is regenerated with boric acid so that borax is formed again. |