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 solution of mixed amide derivatives of the following structures: wherein m is an integral from 0 to 10; n is an integral from 6 to 20; X is OR or NR 1 R 2, wherein OR is OH, C 1 -C 8 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 solution of the mixed amide derivatives by distilling or by extracting with an extractant solvent; adding an acid and an extractant solvent to the aqueous solution from step to perform acidification and extraction to yield an aqueous solution of the acid salt of the long chain amino acid and an extractant phase including the long chain dibasic acid, the alkanoic acid, and impurities; separating the mixture from step into an aqueous phase containing the acid salt of the long chain amino acid and the extractant phase containing the long chain dibasic acid, the alkanoic acid, and the impurities; neutralizing the aqueous phase from step with a basic agent to obtain a crystalline suspension of the long chain amino acid; recovering the long chain amino acid from the crystalline suspension from step by solid-liquid separation to yield an aqueous mother liquor; and in the extractant phase from step, separating the long chain dibasic acid, the alkanoic acid, and the impurities. wherein m is an integral from 0 to 10; n is an integral from 6 to 20; X is OR or NR 1 R 2, wherein OR is OH, C 1 -C 8 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 solution of the mixed amide derivatives by distilling or by extracting with an extractant solvent; adding an acid and an extractant solvent to the aqueous solution from step to perform acidification and extraction to yield an aqueous solution of the acid salt of the long chain amino acid and an extractant phase including the long chain dibasic acid, the alkanoic acid, and impurities; separating the mixture from step into an aqueous phase containing the acid salt of the long chain amino acid and the extractant phase containing the long chain dibasic acid, the alkanoic acid, and the impurities; neutralizing the aqueous phase from step with a basic agent to obtain a crystalline suspension of the long chain amino acid; recovering the long chain amino acid from the crystalline suspension from step by solid-liquid separation to yield an aqueous mother liquor; and in the extractant phase from step, separating the long chain dibasic acid, the alkanoic acid, and the impurities. recovering the alkylamine from an aqueous solution of the alkali hydroxide hydrolysis solution of the mixed amide derivatives by distilling or by extracting with an extractant solvent; adding an acid and an extractant solvent to the aqueous solution from step to perform acidification and extraction to yield an aqueous solution of the acid salt of the long chain amino acid and an extractant phase including the long chain dibasic acid, the alkanoic acid, and impurities; separating the mixture from step into an aqueous phase containing the acid salt of the long chain amino acid and the extractant phase containing the long chain dibasic acid, the alkanoic acid, and the impurities; neutralizing the aqueous phase from step with a basic agent to obtain a crystalline suspension of the long chain amino acid; recovering the long chain amino acid from the crystalline suspension from step by solid-liquid separation to yield an aqueous mother liquor; and in the extractant phase from step, separating the long chain dibasic acid, the alkanoic acid, and the impurities.