Process for the separation of long chain amino acids and dibasic acids

A process for the separation from an aqueous stream of long chain amino acid, dibasic acid, short chain alkylamine, and alkanoic acid of the following structures:

• from at least two of them in an alkali hydroxide hydrolysis mixture of the mixed amide derivatives of the following structures:
• wherein m is an integer from 0 to 10;
• n is an integer from 6 to 20;
• X is OR or NR1R2, wherein OR is OH, C1-C8 monohydric alcohol, or C1-C8 polyhydric alcohol, and R1 and R2 are each independently hydrogen or C1-C8 alkyl group;
• comprising:
• (1) cooling the alkali hydroxide hydrolysis solution of mixed amides to precipitate a mixture of alkali salts of long chain amino acid and dibasic acid;
• (2) separating the mixture of alkali salts of long chain amino acid and dibasic acid by means of solid-liquid separation to provide a mother liquor comprising alkali salt of alkanoic acid;
• and
• (3) separating long chain amino acid and dibasic acid from their mixture or a mixture of their alkali salts by acidification-extraction of long chain dibasic acid with an extractant solvent and an acid, or by selective dissolution of the alkali salt of long chain amino acid in an aqueous solvent, or by selective dissolution of long chain dibasic acid in an aqueous solution of ammonium hydroxide, or ammonium bicarbonate, or ammonium carbonate or their mixture.