Patent ID: 8766000

Claim:
A continuous method for preparing a betaine aqueous solution including a betaine with the following formula (I): wherein: n is equal to 1, 2 or 3; R 1 represents a linear or branched alkyl group, comprising from 1 to 3 carbon atoms; R 2 represents a linear or branched alkyl group, comprising from 1 to 3 carbon atoms; R represents: either a linear or branched hydrocarbonaceous chain, comprising from 3 to 30 carbon atoms; or an -A-NH—CO—R 3 group, R 3 representing a linear or branched hydrocarbonaceous chain, comprising from 3 to 30 carbon atoms; and A representing a linear or branched divalent hydrocarbonaceous group comprising from 1 to 6 carbon atoms, possibly substituted by a hydroxyl group; comprising the reaction of an amine of formula NRR 1 R 2 , R, R 1 and R 2 being as defined above, with an ω-halocarboxylic acid having formula X—(CH 2 ) n —COOH, X representing a halogen atom and n being as defined above, in the presence of water and a base, and wherein said method is carried out in a device made up of at least two consecutive reactors (R1) and (R2), the reactor (R2) being a tubular reactor.