Patented Jan. 9, 1934 1,942,886

UNITED STATES PATENT OFFICE

1942,886 METHOD OF PRODUCING NTRATES AND RECOVERY OF NATBRIC OXDE Bruno Uebler, Berlin, Germany No Drawing. Application June 17, 1929, Serial No. 371,07, and in Germany September 17, 192 2 Claims. (CI. 23-161) My invention refers to the production of ni ride, freed from chlorine in one or the other man trates and has for its particular object to pro ner, so that nitric oxide and chlorine are re duce nitrates from chlorides and nitric acid or COWered Separately, I may proceed in Such man nitrous gases without losing any nitrogen. ner that chlorine is combined, while nitric oxide In the production of nitrates on a large Scale eScapes. 60. the starting material must be readily available I obtain this by conducting nitrosyl chloride and therefore nitrous gases or nitric acid on the at ordinary temperature over scrap iron. Ac one hand and metal chlorides, more especially COrding to the equation potassium chloride, on the other hand are used o for this purpose. All the processes hitherto de 65 : vised, however, do not pay sufficient attention to there is formed besides nitric oxide, which is the losses of nitrogen arising in the reactions. re-used in conversion of metal chlorides into In order to exclude any such losses, the reaction metal nitrates an addition compound of NOCl and ferric chloride. This compound is then de 5 KCl-HNO3=KNO3--HCl (I) composed by heating, and A of the nitrosyl chlo 70 must take place quantitatively in Such manner ride originally used are thereby split off. that all the chlorine escapes in the form of hy I may, however, also proceed in Such manner drochloric acid or that according to the reaction that I conduct the raw nitrosyl chloride also con taining free chlorine at an elevated temperature 20 HNO3--3HCl=2H2O.--NO--3Cl (II) Over metallic iron, the chlorine whether ele 75 all the chlorine escapes as such, Without any mentary Or linked in nitrosyl chloride is then com nitric Oxide being lost. bined With iron, while the nitric oxide escapes In reality, however, the reaction II as a rule aS Such. I may, however, also decompose the occurs differently, viz, nitroSyl chloride after it has been purified in some 25 Suitable manner, by passing it at an elevated 80, HNO3-3HCl=2H2O.--NOCl--2C1 (IIa), temperature over iron, so that merely chlorine is nitrosyl chloride being formed. The difficulty of retained while the nitric oxide in more or less separating Cl from NO rendered all prior proc pure form is returned, directly or indirectly, into esses uncommercial. the liquor from which the original mixture of Cl 30 In my copending application for Letters Pat and NOCl was obtained. 85 ent of the United States, Serial No. 487,023 now If according to one of the modifications above Patent No. 1,899,123, I have described a method described the main quantity of chlorine is re by which this separation can be effected in the moved from the gas mixture and if the nitric following manner: If the gas mixture is cooled oxide resulting in the decomposition of the nitro 35 down to a low temperature, NOCl is liquefied and Syl chloride is returned into the reaction liquor 90 can be separated as a liquid from the chlorine. resulting in the interaction between nitric acid I may, however, also heat the gas mixture first and the chlorides, the chlorine can be removed to a higher temperature and thereafter cool it Without any losses of nitrogen and nitrates can down quickly to a low temperature under Sup noW be produced by acting with nitric acid on 40 ply of air. I then obtain a mixture of NO2 chlorides without any nitrogen being lost. 95 and C1, which can be separated by liquefaction Eacample in the cold and fractional distillation, the chlo rine escaping first. The gas mixture obtained in acting with nitric According to the present invention I also con acid on potassium chloride contained 9% nitrosy 45 vert metal chlorides to metal nitrates by heating chloride, 13.5% chlorine and 77.5% nitrogen. 10 100 the chlorides with nitric acid or nitrous gases, cbms of this gas mixture were conducted at 20° but I make use of another mode of separating C. Over 4 kilograms scrap iron. There resulted nitrosyl chloride and chlorine which is based 10.9 kilograms of a mixture containing 17% me On the addition of NOCl to FeCl3, whereby the tallic iron and 83%. FeCl3NOCl, the inert residual 50 compound FeCl3NOC is formed, while the chlo gases eScaping free from nitrogen oxides. rine escapes as such. On heating the com Warious changes may be made in the details pound, nitroSyl chloride is Split off again in a disclosed in the foregoing specification without substantially pure form and without any mate departing from the invention or sacrificing the rial loSSes. advantages thereof. In order now to decompose the nitrosyl chlo In the claims affixed to this specification no 110 2 1,942,886 selection of any particular modification of the ferric chloride and nitrosyl chloride, the nitric invention is intended to the exclusion of other oxide being re-used in cycle. modifications thereof and the right to Subsequent 2. In the process of producing nitrates from ly make claim to any modification not covered chlorides and nitric acid or nitrous gases the step by these claims is expressly reserved. of regenerating nitric oxide from the nitrosyl 80 I claim:- chloride evolved together with chlorine compris 1. In the process of producing nitrates from ing passing this mixture over ferric chloride to chlorides and nitric acid or nitrous gases, the form an addition compound of ferric chloride and step of regenerating nitric oxide from the nitro nitroSyl chloride, heating said addition com 10 Syl chloride evolved together with chlorine Con pound to recover the nitrosyl chloride in a sub 85 prising passing this mixture over ferric chloride stantially pure form, passing said nitrosyl chlo to form an addition compound of ferric chloride ride over metallic iron at an elevated tempera and nitrosyl chloride, heating said addition com ture to eliminate substantially all the chlorine pound to recover the nitrosyl chloride in a Sub in the form of ferric chloride, the nitric oxide 5 stantially pure form, passing said pure nitrosyl remaining over being re-used in cycle. 90 chloride at Ordinary temperature over iron to form nitric oxide and an addition compound of BRUNO UEBLER,

20 95

00

3. 105

3 5 10

115

45. 120

50 125

55.

80 35

40

145

150