Patent ID: 7390929

Claim:
A method for the continuous synthesis of a monoalkylhydrazine of formula NH 2 —NH—R (I) in which R is selected from the group consisting of C 2 -C 6 alkenyl radical, C 2 -C 6 alkynyl radical, C 1 -C 5 linear alkyl radical containing at least one imine function (—C═N—), and linear or branched C 1 -C 6 alkyl radical carrying at least one functional group selected from the group consisting of OH, C 1 -C 6 alkoxy, C═NH, C≡N, phenoxy, COOH, COO—(C 1 -C 6 alkyl), phenyl or NR 3 R 4 , with R 3 and R 4 each representing independently a C 1 -C 6 alkyl radical or forming a C 2 -C 6 ring, wherein the method comprises the following successive steps: (a) synthesizing the monoalkylhydrazine of formula I in a suitable reactor while causing to react in an alkaline medium and at a temperature in the range between 25 and 45° C. a monochloramine with an anhydrous amine of formula NH 2 —R (II) R having the same significance as for formula I; then (b) demixing the solution obtained following step (a) in an organic phase and an aqueous phase by the addition of anhydrous sodium hydroxide under cooling so that the temperature of the demixing medium does not exceed the boiling points of the compounds; and (c) isolating from the organic phase thus obtained the monoalkylhydrazine of formula I.