Prepn. of 2-phenoxymethyl benzoic acid derivs. of formula (I) comprises (a) converting a phenol of formula (II) to the phenolate in the presence of a basic diluent; (b) mixing the mixt. with a lactone of formula (III); (c) distilling off the diluent; (d) reacting the mixt. at 50-250 degrees C in the melt; and (e) dissolving the liq. melt with water and acidifying. X, Y = halogen, 1-4C alkyl, 1-4C alkoxy or CF3; m = 0-4; n = 0-3.