To produce a new malonic acid compound capable of readily being produced at a low cost without the problem of waste material, and useful as a production raw material for a fluorine-containing carboxylic acid by introducing a specific fluoroalkyl to a specified position of malonic acid (ester).
This new malonic acid compound is the one of formula I [Rf is a 1-8C perfluoroalkyl; R and R' are each H or a 1-10C (un)saturated hydrocarbon], e.g. 3,3,4,4,4-pentafluorobutylmalonic acid or di(methyl or ethyl) 3,3,4,4,4- pentafluorobutylmalonate. The compound of formula I is obtained by reacting a compound of formula II with an alkali metal(halide) or an alkali metal alcoholate in a polar solvent to provide an alkali metal salt, and further reacting the obtained salt with a compound of formula III.
KATO KOJI
ARAI SHOJI
