A process for the separation of long chain amino acid, long chain dibasic acid, alkylamine, and alkanoic acid of the following structures: from at least two of them in an alkali hydroxide hydrolysis mixture of 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 NR 1 R 2, wherein OR is OH, Ci-Cs monohydric alcohol, or Ci-Cs polyhydric alcohol, and R 1 and R 2 are each independently hydrogen or Ci-Cs alkyl group; the process comprising: recovering the alkylamine from an aqueous solution of the alkali hydroxide hydrolysis mixture of the mixed amide derivatives by distilling or by extracting with an extractant solvent; cooling the aqueous solution of step to precipitate a mixture of alkali salts of the long chain amino acid and long chain dibasic acid; separating the mixture of the alkali salts of long chain amino acid and long chain dibasic acid by means of solid-liquid separation to provide a mother liquor; separating each of the long chain amino acid and long chain dibasic acid from the mixture of the alkali salts of the long chain amino acid and long chain dibasic acid, by acidification-extraction of the long chain dibasic acid with an extractant solvent, or by selective dissolution of the alkali salt of the long chain amino acid in an aqueous solvent, or by selective dissolution of the long chain dibasic acid in an aqueous solution of ammonium hydroxide, ammonium bicarbonate, or ammonium carbonate or their mixture; and adding an acid to the mother liquor of step to obtain the alkanoic acid. n is an integer from 6 to 20; X is OR or NR 1 R 2, wherein OR is OH, Ci-Cs monohydric alcohol, or Ci-Cs polyhydric alcohol, and R 1 and R 2 are each independently hydrogen or Ci-Cs alkyl group; the process comprising: recovering the alkylamine from an aqueous solution of the alkali hydroxide hydrolysis mixture of the mixed amide derivatives by distilling or by extracting with an extractant solvent; cooling the aqueous solution of step to precipitate a mixture of alkali salts of the long chain amino acid and long chain dibasic acid; separating the mixture of the alkali salts of long chain amino acid and long chain dibasic acid by means of solid-liquid separation to provide a mother liquor; separating each of the long chain amino acid and long chain dibasic acid from the mixture of the alkali salts of the long chain amino acid and long chain dibasic acid, by acidification-extraction of the long chain dibasic acid with an extractant solvent, or by selective dissolution of the alkali salt of the long chain amino acid in an aqueous solvent, or by selective dissolution of the long chain dibasic acid in an aqueous solution of ammonium hydroxide, ammonium bicarbonate, or ammonium carbonate or their mixture; and adding an acid to the mother liquor of step to obtain the alkanoic acid. recovering the alkylamine from an aqueous solution of the alkali hydroxide hydrolysis mixture of the mixed amide derivatives by distilling or by extracting with an extractant solvent; cooling the aqueous solution of step to precipitate a mixture of alkali salts of the long chain amino acid and long chain dibasic acid; separating the mixture of the alkali salts of long chain amino acid and long chain dibasic acid by means of solid-liquid separation to provide a mother liquor; separating each of the long chain amino acid and long chain dibasic acid from the mixture of the alkali salts of the long chain amino acid and long chain dibasic acid, by acidification-extraction of the long chain dibasic acid with an extractant solvent, or by selective dissolution of the alkali salt of the long chain amino acid in an aqueous solvent, or by selective dissolution of the long chain dibasic acid in an aqueous solution of ammonium hydroxide, ammonium bicarbonate, or ammonium carbonate or their mixture; and adding an acid to the mother liquor of step to obtain the alkanoic acid.