2,698,819 United States Patent Office Patented Jan. 4, 1955, 2. ment at the beginning of the paragraph. It will be un 2,698,819 derstood that the compounds, by behavior and upon analysis, demonstrate the presence of the quadrivalent ETHYLENEDIAMENE TETRAACETIC ACID PERI. acid radical (C10H12OgNal, and of three iodine atoms, ODDES AND COMPOSITIONS THEREOF: together with the existence of four monovalent bonds satisfied in total or in part by hydrogen and for the rest Leo W. Ziemak, Pittsburgh, Pa., assignor to Chilean by, an alkali metal substituent, or satisfied by one bivalent: Nitrate Sales. Corporation, New York, N.Y., a corpo alkaline earth element with the remaining two mono ration of New York valencies supplied by hydrogen or an alkali metal sub stituent. In this connection, it is to..be remembered that Norawing. Application June 26, 1951, O ultimate analyses of compositions, for determining a Serial No. 233,711 molecular formula of 700 or higher mass or weight units, 8. Caints. C. 167-7) : have uncertainty as to the number of hydrogens present: and that the foregoing is stated as a type formula, rather. This invention relates to new chemical compounds hav than as meaning that the number of hydrogens present, s -ing properties adapting them to bactericidal uses, and to 5 for example in the hydrogen periodide compound of bactericidal compositions-including the same. ethylenediamine tetra-acetic acid, is sixteen or seven For the sterilization of water it is desirable to have a tee. composition which can be prepared in a dry, stable tablet This general empiric formula for the compound also, or pill form which upon dissolution in water will re includes complexes in which the basic component is one lease iodine, and sterilize the water without giving - a 20 of the compounds of said formula, and the complex sub strong offensive taste thereto by reason of end products, stance is one of molecular association in which there is and make the water available for safe drinking or for bound to a stated compound containing ammonium as a laving wounded areas. Likewise, it is desirable to have substituent, an excess of periodide such as ammonium a dusting powder which is stable and non-hygroscopic, iodide-iodine. and which can be employed directly upon wounds. 25, EXAMPLE I Proposals have been made to prepare iodine-releasing compositions, in which the iodine is not originally free Dipotassium salt of ethylenediamine tetra-acetic acid but separates when the composition is brought into con potassium triodide. tact with water, either in preparing a sterilizing or sterilized 13.8 grams of U. S. P. potassium carbonate was dis-- liquid, or when used as a dusting powder. Many such 30. solved in 20 cc. of water, and to this was slowly added proposals recommend the use of aromatic or other cyclic 14.6 grams of ethylenediamine tetra-acetic acid. The compounds; such as iodized aromatic chloramine, which mixture was heated gently until a homogeneous solution upon releasing iodine has a high odor of chlorinated wa was obtained. A second solution was prepared by dis ter and phenol: or such as morpholine periodide. A Solving 8.3 grams of U.S. P. potassium iodide in 20 cc. difficulty in such preparations is that the composition of water; and 14 grams of U.S. P. iodine. The sec should be stable in moist air, yet capable of reacting quick ond solution was slowly added, with stirring, to the first ly with water to release the iodine: these are contradic and the resulting solution heated to about 75 C. Upon. tory, and some prior materials have exhibited stability in cooling, a dark crystalline mass settled out almost im air but at the expense of timely and effective release of mediately. The reaction mixture was allowed to stand the iodine upon contact with water or serum, and oth 4. for several hours in an ice bath. The crystals were then ers have effective release at the expense of storage stability rapidly washed first with cold dilute aqueous potassium wherewith some compositions are even deliquescent. iodide, then with cold distilled water, and finally with 95 Furthermore, the end products must not themselves be percent ethyl alcohol. The product was then dried over. toxic or caustic even with accidentally acquired high phosphorus pentoxide; yield 23.5 grams. dosages: and by great preference they should form only 45 The product is crystalline and exhibits, great, stability water-soluble compounds with alkaline earths. Such as in the atmosphere. The vapor tension is very low and . naturally present calcium salts. the odor of iodine is not discernible. When ground to It has long been known that greater quantities of iodine a fine powder, it has a dark red-brown color. It has a can be held in solution in an iodide solution than in wa solubility of 98.8 grams per liter, as measured by the ter alone: apparently by reason of existence of Such com quantity of iodine released when a saturated solution is plexes as Ki-2, so-called potassium periodide KI3. formed. The aqueous solution is very similar to that of However, such complexes are unstable. iodine in aqueous potassium iodide. Upon analyses, the It has now been found that a water-soluble, atmos empiric formula closely corresponds to C10H14OaN2K3I3 pherically-stable compound of high available iodine con or C10H13O8N2K3 is, it being remarked that one hydrogen tent, and of crystalline nature, can be prepared by react atom has a weight or mass of one unit in a molecule of ing an alkylamine polycarboxylic acid, namely ethylene about 788 weight or mass units. The theoretical per diamine tetra-acetic acid with an alkali periodide, alkaline centage of iodine in a compound of the empiric formula earth periodide, or hydrogen periodide, that is, with C10H14OsN2K33 is 48.3%; and, assuming that two iodine the double salt or compound of the alkali or alkaline 60 atoms are active, the theoretical percentage of active earth iodide, or hydrogen iodide, with iodine. iodine is 32.2%. The experimental value for active The preferred compound is obtained by treating the iodine determined by titration was 30% : but upon analy tetra-potassium salt of ethylenediamine tetra-acetic acid sis by the Parr bomb method or by the standard U. S. P. with potassium periodide, and separating the molecular method (iodate), the total iodine was noted as 48.8%. complex by crystallization. 6 The compound exhibits great stability to dry heat. A Potassium, sodium, ammonium (which herein is the sample, which had been dried over phosphorus pentoxide, chemical equivalent of an alkali metal element), cal was placed in a drying oven at 100-110° C. for over 24 cium, magnesium, and even hydrogen periodides, or hours; the weight-loss was only 1.2 to 1.3 per cent. The mixtures thereof, may be utilized; and the general em weight-loss occurred within 16 hours of drying; there was piric formula of the compound may be stated as 70 no additional loss of weight even though the drying period CoH12O3N2 MaR3, in which M is a monovalent em was extended to a total of 25 hours. The weight-loss was piric substituent selected from the group consisting of hy apparently due to loss of moisture, for the total iodine drogen, potassium, sodium, and ammonium; and R is content per mole of the triiodide was slightly higher than a divalent empiric substituent selected from the group that found before the test. After the test, the sample could consisting of calcium, magnesium, dihydrogen, hydrogen 75 not be distinguished, by inspection, frcm one which had potassium, hydrogen-sodium, hydrogen-ammonium, that not been so treated. is, compounds of the form Edita (Ca3, Edita The compound is non-hygroscopic in the 2EEGosphere. CaHK23J, Edita Caksa, Edita (H3K23, Edita A sample, which had been dried at 100 to 10 C. for HK313, Edita (H2K2NH431, and the like are includ 16 hours, was exposed to 65 per cent relative humidity at ed, where Edita is an abbreviation for the ethylene 80 70 F. for over 60 hours. The gain in weight was diamine tetraacetic acid radical in the bracketed state only 1.2 per cent, practically the weight lost on drying. 2,698,819 3 4. EXAMPLE 8 showedA second no samplegainin weightwhich inhad the beensame driedperiod over when silica exposed gel to 65 per cent relative humidity at 70 F. Ethylenediamine tetra-acetic acid potassium triodide 66.4 grams of U. S. P. potassium iodide was dissolved EXAMPLE 2 5 in 200 cc. of water, and to this was added 14.6 grams of ethylenediamine tetra-acetic acid. The mixture was heat The disodium salt of ethylenediamine tetra-acetic acid ed until a homogeneous solution was obtained; and then sodium triiodide was prepared as in Example 1, employ 50.8 grams of powdered U. S. P. iodine was slowly added, ing 10.6 grams of U. S. P. sodium carbonate and 7.5 with stirring. The reaction mixture was heated on a grams of U. S. P. sodium iodide in lieu of the potassium 10 steam bath until all the iodine had dissolved. Upon cool salts; yield 32 grams. The product has essentially iden ing the reaction mixture, a dark crystalline mass began tical behavior and stability with that of Example 1; and to settle out almost immediately. The mixture was al its formula upon analysis is in agreement with lowed to stand for several hours in an ice bath. The crystals were separated by filtration, and washed rapidly 5 first with cold dilute aqueous potassium iodide, then EXAMPLE 3 with cold distilled water, and finally with 95 per cent The corresponding disodium salt of ethylenediamine ethyl alcohol.