SU462593A1 - Method for restoring catalytic activity of strongly basic anion exchange resins - Google Patents

Description

anion exchange resin is shown in the table.

In the examples given in the table, the synthesis of etriol is carried out by condensation of n-butyric aldehyde with formaldehyde (1: 4) on an ion-exchange column (d - 25 mm, h 400 mm) filled with anion exchange resin AB-17-8. A mixture of 33.6% formalin, n-butyric aldehyde (which is taken in an amount of -25% of the calculated value), and NaCl are charged to the mixing flask-mixer. At a tempera- ture of 10–15 ° C, this mixture is passed through an ion exchanger for 10 min, after which the remaining 75% n-butyraldehyde is gradually fed over 10 min. The circulation at 15–20 ° C is continued for another 10 min at a rate of 12 l / h, then the temperature in the column rises to 50–55 ° C and the circulation is continued at this temperature for another 30 min. At the end of the synthesis, the resin is washed with hot (50-55 ° C) distilled water, after which it is treated with a 5% aqueous solution of NaOH at 50 ° C to remove the formic acid. The ion exchanger is washed from the alkali residues on the column, then the aldehyde is condensed again with formaldehyde. After a decrease in catalyst activity, which was observed after 200 hours of work on alternating condensation operations,. and regeneration (total cycle 2 hours), the anion exchange resin is discharged from the column into the mixer and treated with 500 ml of an aqueous alcoholic solution of alkali (water: ethanol: caustic soda - 1: 1: 0.05) at 50 ° C. At the same time, a white powdery product adsorbed on it is washed from the surface of the resin granules and separated together with the regenerating solution by decantation.

After the resin is completely washed and subsequently regenerated with an aqueous solution of caustic soda, the catalytic activity of the anion exchanger is completely restored. After a further 150 hours of operation, the catalytic activity of the anion exchanger is reduced, it is re-treated in a countercurrent column at 50 ° C with an alcoholic water and sodium hydroxide solution of the above composition. Splitting off

From this resin, the product is carried away from the top of the column. The resin is washed with distilled water until the turbidity completely disappears and is treated with an aqueous solution.

NaOH. In this case, the catalytic activity of the anion exchanger is restored to the original.

Similar results are obtained on strong base ion exchange resins Dowex-1,

Dowex-2, AB-17-4, AN-17-10 and others.

Table

 Initial resin exchange capacity 3.2 mEq / g

 Processing resin alcohol NaOH.

Subject invention

A method of restoring the catalytic activity of strongly basic anion-exchange resins by treating with a chemical reagent, characterized in that, in order to increase the completeness of the recovery of activity, after the synthesis of aliphatic alcohols, the strong anion exchangers are treated with an alcohol-aqueous caustic alkali solution at a ratio of alcohol: water: caustic alkali of 0.5 -2: 0.5-2: 0.02: 0.1, at a temperature of 40-55 ° C.