Ammonia → Ammonia

Participants

Reaction Steps

An ammonium aspartate solution is prepared in a reactor with a capacity of 2 liters by suspending 133.1 g (1 mol) of aspartic acid in 500 g of water with stirring and adding 68 g (1 mol) of 25% strength aqueous ammonia solution. The resulting clear solution corresponds to the composition of an ammonium aspartate solution as produced by enzymatic addition of ammonia onto fumaric acid after removal (stripping) of excess ammonia. 98 g of concentrated sulfuric acid are added to the solution over the course of 30 minutes, during which the aspartic acid precipitates. The complete suspension is evaporated to dryness under water pump vacuum while stirring at 130° C., and the thick melt remaining as residue is polycondensed for 4 hours under water pump vacuum at 180° C. to form a foam. The solidified foam is broken up at intervals to produce powder particles 0.1-5 mm in size. After cooling, the polycondensate is taken up in 2 liters of water. The residue is filtered off and washed with water and dried at 70° C. The yield of polyaspartimide is 96.6 g (99.6% of theory). The K value of the sodium polyaspartate is 35.9.

Provenance & Evidence