Preparation of Irondiphosphonic Acid, and Organic Amines

The reaction of aqueous suspension of finely dispersed iron with one equivalent of (1-hydro xyethylidene)diphosphonic acid ([H.sub.4]L) results in poorly soluble iron(II) (1-hydro xyethylidene)diphosphate Fe[H.sub.2]L * [H.sub.2]O. The reaction with two equivalents of the acid gives a water-soluble compound Fe[([H.sub.3]L).sub.2], which undergoes disproportionation up to Fe[H.sub.2]L * [H.sub.2]O and [H.sub.4]L. The reaction of a Fe[H.sub.2]L * [H.sub.2]O aqueous suspension with an organic amine results in the dissolution of the complex. Heating the Fe[H.sub.2]L * [H.sub.2]O aqueous suspension in a pressure reactor at 150[degrees]C in the presence of KF catalytic amounts causes the formation of a new crystal phase and X-ray-amorphous admixtures. Keywords: (1-hydroxyethylidene)diphosphonic acid, carbonyl iron, reduced iron, 2-aminoethanol, 2-amino-2(hydroxymethylpropane)-1,3-diol DOI: 10.1134/S1070363218030180