EPaRenees: Ray 29, 1945 2,377,193 UNITED STATES PATENT office 2,377,193 PROCESS FOR THE PRODUCTION OF BY DROXYAMMONUM, CLOB OE Philip F. Tryon, Terre Baute, nd, assignor to Commercial Solvents Corporation, Terre Haute, Ind., a corporation of Maryland No Drawing. Application October 9, 1943, Serial No. 505,664 10 Claims. (c. 23-87) My invention relates to a process for the pro and used as the source, of solvent for another duction of hydroxylammonium chloride. More reaction solution. The crystals obtained from particularly, it relates to a process for the pro this process are preferably dried for approxi duction of hydroxylammonium chloride by there- . mately two hours at 70-80 C. action of hydroxylammonium sulfate with hydro The reaction is effected with satisfactory re chloric acid. sults without the presence of a lower alcohol sol Prior methods of preparing hydroxylammoni went. However, slightly better yields are obtained um chloride have generally been unsatisfactory and the separation of the reaction product is in view of the relatively long and involved pro more easily accomplished when utilizing a lower cedures utilized, and the comparatively low yields O alcohol solvent, such as methanol. Also, it is obtained thereby, Typical of the former methods sometimes advantageous to heat the reaction employed in the synthesis of hydroxylammonium mixture to an elevated temperature of approx chloride, is the procedure involving the use of so imately 70° C. In such instances, however, little dium nitrite, sodium bisulfite and sulfur dioxide if any advantage is obtained by keeping the lower . to produce sodium hydroxylamine disulfonate, 15 alcohol reaction mixture at an elevated tempera which is in turn treated with acetone to form ac ture for an extended length of time. etoxime. On hydrolysis of the latter with hydro There are several factors to be considered in chloric acid, hydroxylammonium chloride is pro selecting the lower alcohol Solvent. Methanol, duced, ethanol, propanol, butanol, etc., are all satisfac I have now discovered that hydroxylammonium 20 tory is solvents, but methanol, being more readily chloride can be prepared in yields of 85 per cent available, was used for the most part throughout and above merely by treating hydroxylammonium the experiments. Furthermore, it was found that sulfate with hydrochloric acid in aqueous, or . the reaction product was more easily separated aqueous alcoholic solutions. To obtain hydroxyl from a methanol reaction Solution than from the ammonium chloride from hydroxylammonium 25 other alcohol solutions. The amount of alcohol sulfate under such conditions, is entirely contrary used in the reaction mixture and in the wash re to that which one skilled in the art would nor spectively should be of the order of one, to one and mally expect, since it is known that the solubility one-half equivalents for each equivalent of hy of hydroxylammonium chloride in water is great droxylammonium sulfate. When the number of er than that of hydroxylammonium sulfate. For 30 equivalents of alcohol is increased, there is a de example, at 25° C. hydroxylammonium chloride crease in the yield of hydroxylammonium chlo is soluble in water to the extent of 95 grams per ride, probably due to the fact that greater amounts 100 grams of water, while hydroxylammonium of hydroxylammonium chloride are dissolved in Sulfate is soluble in water to the extent of only 64 the increased amount of alcohol and not com grams per 100 grams of water. Notwithstanding 35 pletely recovered therefrom. this fact, however, an aqueous reaction mixture The ratio of equivalents of hydrochloric acid to containing one equivalent each of hydroxylamine, the hydroxylammonium sulfate has a decided Sulfuric acid, and hydrochloric acid has been effect upon the yield of hydroxylammonium chlo found to yield 60 per cent of the hydroxylamine ride. In instances where one equivalent, or as crystalline hydroxylammonium chloride and 40 slight y less of hydrochloric acid is utilized, the only 3 per cent of the hydroxylamine as the sul product obtained is not entirely hydroxylammo fate. nium chloride, but some of the sulfate is also pre The reaction is usually effected at atmospheric cipitated, along with the chloride. In order to pressure, and preferably in the presence of a suit secure satisfactory yields there should be in the able solvent, such as a lower alcohol, at a tem 45 reaction mixture an excess of the hydrochloric perature of 0° C. to 85 C., and preferably from acid and preferably there should be from one and 20 C. to 70° C. The precipitation of the hy one-fourth to two equivalents of hydrochloric droxylammonium chloride is facilitated by cool acid for each equivalent of the hydroxylammo ing the reaction solution, after which the solid nium sulfate. For example, a reaction mixture hydroxylammonium chloride may be removed 50 consisting of one equivalent of hydroxylammo from the reaction solution by any suitable means, nium sulfate, one and one-half equivalents of 38 preferably by filtration. The product obtained per cent hydrochloric acid, and one equivalent of in this manner is relatively pure; however, it is methanol yields about 80 per cent of the theoreti advantageous to wash it with an equivalent pro cal amount of the hydroxylammonium chloride portion of a lower alcohol, which may be saved 55 in a state of approximately 99 per cent purity. , 2 2,877, 193 The degree of purity of the reactants is an TABLE important factor in the reaction. Better yields are obtained from relatively pure hydroxylam Equivalent proportions monium sulfate than from the impure material, even though equivalent quantities are used; is E9, Meois in re. Meor in Percent there is noted a corresponding decrease in yield Run (98%) (38%) action wash yields with each decrease in per cent of purity of the l-A----- 1.0 2.0 1.0 (fresh)----- 1.0 (fresh)-- 75 hydroxylammonium sulfate. The same is true 1-B----- 1.0 2.0 1.0 (wash A) -- 1.0 8E3 - - 8. of the concentration of hydrochloric acid. For 1-C -- l, 0 2.0 1.0 (wash B). - 1.0 (fresh)-- 81 0 example, lower yields were obtained using 33 per 2-A----- , 0 1.5 . .0 Sis - - - - - .0 (fresh).--- 68 cent hydrochloric acid than were secured when 2-B. 1.0 1.5 1.0 (wash A) - 1.0 (fresh). 77 using 38 percent hydrochloric acid. 2-C----- 1.0 1.5 1.0 (wash B)--- 1.0 (fresh). 77 3-A---- 1.0 1.25 1.0 (fresh)..... 1.0 (fresh). 63 My invention may be further illustrated by the 3-B----- 1.0. 1.25 1.0 (washA)2- .0 E3: 7a. following specific examples: 3-C----- 1.0 1.25 1.0 (wash B)- 1.0 (fresh)-- 73 5 4-A.----- 1.0 1.01.0 (fresh)--... 1.0 (resh)--- 58 EXAMPLE 4-B----- ... O 1.0 . .0 &S A)--- 1.0 (fresh). 61 4-C----- 1.0 1.0 1.0 (washB)--- 1.0 (fresh). 65 Hydroxylammonium chloride was prepared by 5-A----- 1.0 0.9 1.0 (fresh) 1.0 (fresh). 48 heating a mixture consisting of 167 parts of 98 5-B----- ... O 0.9 1.0 (wash A). 1.0 E3 -- 55 5-C----- 1.0 0.9 1.0 (wash B). 1.0 (fresh 5t per cent hydroxylammonium sulfate, 384 parts 20 of 38 per cent hydrochloric acid and 75 parts of 6-A---- 1.0 0.8 1.0 (fresh)----. 1.0 (fresh) 45 isopropyl alcohol in a suitable reaction vessel to a 6-B---- 0 0.8 1.0(wash A). 1.0 33 51 temperature of approximately 70° C. When the 6-C----- .0 0.8 1.0 (wash B).--- 1.0 (fresh) 49 reaction appeared to be complete, the mixture 1 Hydroxylamine sulfate. was cooled in ice water to a temperature of ap Hydroxylammonium chloride. proximately 18°C. The crystalline hydroxylam The following table of results obtained when monium chloride thus formed was filtered, washed the reaction mixture was heated to 70° C., cooled With 60 parts of isopropyl alcohol, and dried at to 18° C., and filtered, illustrate the fact that approximately 70° C. for 2 hours. The product the concentration of acid has a definite effect thus obtained corresponded to a yield of 75 per 30 On the yields obtained: cent. ExAMPLE II TABLE II Equivalent proportions One hundred and sixty-seven parts Of 98 per cent hydroxylammonium sulfate and 384 parts 35 of 38 per cent hydrochloric acid was heated in a MeOH HS 1 BC MeOH Percent Suitable vessel to a temperature of 70'. C., with S reaction in wash yield 2 Constant agitation, at which time there was added to the mixture 80 parts of ethanol. The reaction mixture was then cooled as in Example I, and (USING 38% HCl) the crystalline product separated from the reac 40 tion mixture, yielding a material corresponding 1.0 1.5 | 1.0 | 1.0 77 to a yield of 73 per cent. (USING 33% EIC) ExAMPLE I 45 1.0 1.5 1.0 1.0 69 A mixture consisting of 150 parts of water, 32 parts of methanol, and 84 parts of 98 per cent (USING 28%, HCl) hydroxylammonium sulfate, was treated to satu ration at 18° C. with hydrogen chloride. The le ... 5 .0 0. 60 50 crude hydroxylammonium chloride, obtained in Hydroxylammonium sulfate. this manner, was filtered, washed with 32 parts Hydroxylammonium chloride. of methanol, and dried at 70° C. for two hours. From the foregoing description, it will ba ap The crystalline product obtained in this manner parent to, those skilled in the art that numerous weighed 59.5 grams, corresponding to a yield of equivalents and modifications of the process de 85 percent. scribed herein, exist. For example, instead of ExAMPLE IV utilizing hydroxylammonium sulfate, the acid A mixture consisting of 163 parts of 98 per cent V Sulfate may be employed. In such instances, it hydroxylammonium sulfate, 384 parts of 38 per is preferable to employ at least two moles of cent hydrochloric acid, and 64 parts of methanol 60 hydrochloric acid for each mole of hydroxylam which had been used as the wash methanol in monium acid sulfate present. Other equivalents Example III, was heated to a temperature of 70° and modifications of my process will be readily C., after which the heat was cut off and the re recognized by those skilled in the art. action mixture cooled in ice water to a temper My invention now having been described, what ature of 18°C. The crystalline product obtained I claim is: - in this manner was filtered, washed with meth 1. In a process for the production of hydroxyl anol, and dried at a temperature of 70° C. for ammonium chloride, the step which comprises two hours. The hydroxylammonium chloride, reacting aqueous hydrochloric acid with hy obtained in this manner, corresponded to a yield droxylammonium sulfate. of 81 per cent. 70 2. In a process for the production of hydroxyl The following table illustrates in tabular form. annonium chloride, the step which comprises the results obtained when hydroxylammonium reacting aqueous hydrochloric acid with hy sulfate, 38 percent hydrochloric acid and meth droxylammonium sulfate in the presence of a anol were heated to a temperature of 70° C., Suitable solvent. cooled to 18°C., and filtered. 3. In a process for the production of hydroxyl as?,198 3 ammonium chloride, the step which comprises droxylammonium sulfate in the presence of a reacting aqueous hydrochloric acid with hy lower aliphatic alcohol, and at a temperature be droxylammonium sulfate in the presence of a tween 0° and 85 C. lower aliphatic alcohol. 8. In a process for the production of hydroxyl 4. In a process for the production of hydroxyl ammonium chloride, the step which comprises ammonium chloride, the steps which comprise reacting aqueous hydrochloric acid with hy reacting hydroxylammonium sulfate with aque droxylammonium sulfate in the presence of a ous hydrochloric acid, and cooling the resulting Suitable solvent, and at a temperature between reaction mixture to a temperature at which said 20° and 70° C. hydroxylammonium chloride precipitates, 0 9. In a process for the production of hydroxyl 5. In a process for the production of hydroxyl ammonium chloride, the steps which comprise ammonium chloride, the steps which comprise agitating a mixture of aqueous hydrochloric reacting aqueous hydrochloric acid with hy acid and hydroxylammonium sulfate, cooling the droxylammonium sulfate in the presence of a resulting reaction mixture to a temperature at . lower aliphatic alcohol, and cooling the resulting 5 which hydroxylammonium chloride precipitates, reaction mixture to a temperature at which said and separating said hydroxylammonium chloride hydroxylammonium chloride precipitates. from the reaction mixture. 6. In a process for the production of hydroxyl 10. In a process for the production of hy ammonium chloride, the steps which comprise droxylammonium chloride, the steps which com reacting aqueous hydrochloric acid with hy 20 prise heating a mixture consisting of aqueous droxylammonium sulfate in the presence of hydrochloride acid, hydroxylammonium sulfate, methanol, and cooling the resulting reaction and a lower aliphatic alcohol, cooling the re mixture to a temperature at which said hydroxyl sulting reaction mixture to a temperature at ammonium chloride precipitates. which hydroxylammonium chloride precipitates, 7. In a process for the production of hydroxyl and separating said hydroxylammonium chloride ammonium chloride, the step which comprises from the reaction mixture. , reacting aqueous hydrochloric acid with hy PHILIP F. TRYON.