The synthesis of amphoteric F-alkylated bitailed surfactantsderivedfrom new β-aminoacid intermediates is described. N-alkyl N-benzyl amines or N-alkyl N-methyl amines are added to acrylic acid. The β-amino acids obtained are quaternized by 2-F-alkyl ethyl acetates or thioacetate bromides to produce the F-alkylated double-chain carboxybetaı̈nes.