Ciba-geigy Corporation

Thomas Engert

Hans Stephan

Walter Wolf

A process is described for the preparation of hydroxybenzylphosphonates of the formula I ##STR1## which involves A) reacting a phenol of the formula II ##STR2## with an amine of the formula III ##STR3## formaldehyde or paraformaldehyde and a protonic acid H.sub.n A to give a salt of the formula IV ##STR4## B) distilling off the water of reaction which forms, and C) reacting the reaction mixture, or the salt IV isolated therefrom, with a trialkyl phosphite of the formula ##STR5## in which H.sub.n A is an organic or inorganic acid having n protons,

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Gross-Rohrheim, Germany

Thomas Engert