Patented June 15, 1937 2,083,691 UNITED STATES PATENT OFFICE 2,083,691 METHOD OF PRODUCING A KAMA, PERG). Ot - George Lewis Cunningham, Niagara Falls, N. Y. assignor to The Mathieson Alkali Works, no, New York, N. Y., a corporation of Virginia No Drawing. Application 29, 1988 serial No. 105,103 6 Claims. (C123-184) This invention relates to the production of than about 2:1 and the proportion of benzene anhydrous sodium peroxide, Na2O. The inven being sufficient to maintain the hydrazo and azo tion provides a process for manufacturing an compounds in solution. The alcohols and alco hydrous sodium peroxide producing a product of. holates of the alcohols having not more than 4 5 high purity with good economy, with respect both carbon atoms are useful in the process of the to material costs and operating costs. - invention. The oxidation reaction may be typi The generally practiced processes for the pro fled as follows: duction of sodium peroxide all involve the use of metallic sodium and the use of rather high 10 temperatures, and consequently involve high 0. The process is made cyclic by regenerating the costs in both of these respects. The process of hydrazo benzene by reducing the azo benzene re temperaturesthis invention, unnecessary however, makes and, theinstead use ofof high re sulting from the oxidation with a sodium amal quiring metallic sodium, is applicable to the sodi gam, this reaction also producing the sodium . 5 um amalgam produced in conventional mercury alcoholate consumed in the oxidation. This re 5 cathode electrolytic cells. duction reaction may be typified as follows: Manchot & Herzog have hitherto described the production of sodium peroxide by reaction be tween oxygen and a methyl alcohol solution of 20 hydrazo benzene and sodium methylate (Anna For the complete cylic process, the reaction ma 20 len, 1901, 316, 331). The sodium peroxide thus thus be typified as follows: produced, however, is recovered, not as anhydrous Sodium peroxide, but as a hydrate of sodium hy 2Na(amalgam) --O2->Na2O2 drogen peroxide, NaOOH, as sodium hydrogen This invention includes two embodiments of the esperoxide monohydrate, NaOOH.H2O, for exam cyclic process, one a two-stage process in which 25 ple. This is due to the fact that sodium peroxide the oxidation of the hydrazo compound and the reacts with methyl alcohol about as follows: reduction of the azo compound are effected as Separate operations, the anhydrous sodium pe Nago--CH3OH-CH3ONa--NaOOH. roxide being separated between the oxidation and so I have discovered that this reaction between the reduction, and another combining the oxida 30 sodium peroxide and methyl alcohol, for example, tion and reduction in a single stage. to produce sodium methylate and sodium hydro According to the first of these embodiments of gen peroxide can be suppressed by effecting the the cyclic process, the oxidation of the hydrazo oxidation of the hydrazo compound in an anhy compound is effected as just described, the pre as drous benzene solution of the alcoholate and by cipitated anhydrous sodium peroxide is then sep 35 so limiting the concentration of alcohol present arated from the benzene-alcohol mixture, and as Such and as alcoholate that the molar ratio the azo compound in solution in the anhydrous of alcohol to the hydrazo benzene does not ex mixture of benzene and alcohol is then reduced ceed about 2:1 and that the molar ratio of ben with a sodium amalgam to regenerate the hy 40 Zene to alcohol is not less than about 10:1. I am drazo compound which is returned to the oxida 40 thus able to adapt this known Oxidation of hy tion. t drazo benzene to the direct production of anhy According to the second of these embodiments drous sodium peroxide. of the cyclic process, the hydrazo compound is According to this invention, an appropriate oxidized in the presence of the sodium alcoholiate 45 hydrazo compound is Oxidized, by blowing with to form the corresponding azo compound and to 45 oxygen or air or other appropriate oxygen-con form the anhydrous sodium peroxide and in the taining gas for example, in the presence of Sodi presence of Sodium amalgam to regenerate the un methylate, for example, in an anhydrous mix hydrazo compound by reducing the azo com ture of benzene and methyl alcohol to form the pound resulting from the oxidation, and to pro 50 corresponding azo compound and to precipitate duce additional sodium alcoholate, in an anhy 5) anhydrous sodium peroxide, the molar ratio of drous mixture of benzene and alcohol, the molar benzene to alcohol being not less than about 10:1 ratio of benzene to alcohol being not less than or better not less than about 20:1, the molar about 10:1, the molar ratio of alcohol including ratio of alcohol including alcohol present as al alcohol present as alcoholate to the hydrazo com 55 coholate to the hydrazo compound being not more pound not exceeding about 2:1, and the propor 55 2 2,088,691. tion of benzene being sufficient to maintain the ide, magnesium peroxide or similar compounds. hydrazo and azo compounds in solution, the sodi While the invention has been described with um peroxide formed, and thrown out of solution, particular reference to the production of anhy being maintained in Suspension in the benzene drous sodium peroxide, it is also useful for the 5 alcohol mixture, by agitation for example, and production of anhydrous peroxides of potassium separating sodium peroxide from withdrawn por and the other alkali metals. For the production tions of the benzene-alcohol mixture, by filtra of anhydrous alkali metal peroxides, the alkali tion for example. In this embodiment of the invention, the molar ratio of alcohol including metal alcoholate or the alkali metal amalgam 0 may be used generally as the sodium alcoholate alcohol present as alcoholate to the hydrazo com and sodium amalgam more particularly described. O pound is with advantage limited not to exceed While the equations above set forth as typify about 2:1. ing reactions involved in the invention are gener While I have referred specifically to hydrazo ally descriptive of these reactions, it appears that benzene, and the corresponding oxidation product the proportion of alcohol required for complete 5 azobenzene, as the intermediates by which the anhydrous sodium peroxide is produced, hydrazo reaction of the intermediate, more particularly 5 benzene and azobenzene typify the intermediates in the first described embodiment of the cyclic which may be designated hydrazo compounds and process, may be less than that theoretically indi azo compounds known to react to produce perox cated to be required by these equations. It may ides in this manner. For example, the intermedi be, for example, that the total reaction may in ates useful in carrying out this invention include clude reactions such as the following: 20 hydrazo benzene, the hydrazo toluenes, particu larly p-hydrazotoluene, p-ethyl hydrazobenzene, the hydrazo triazols, phenyl hydrazone, anthra hydroquinone, di-hydrophenanthrenechinon, and the amino substituted aromatic hydrazo con In any event, the efficiency of the process does not 25 pounds such as the amino substituted hydrazo appear to be directly dependent upon the use of benzenes, toluenes, Xylenes and naphthalenes, maximum proportions of alcohol within the limits and the corresponding a Zo compounds. previously specified. The following examples Will illustrate the prac I claim: tice of the process of the invention: 1. In the production of anhydrous alkali metal 30 peroxides, the improvement which comprises oxi Eacample I dizing an hydrazo compound in the presence of 182 parts (by weight) of azobenzene are dis an alcoholate of the alkali metal and of an solved in 1700 parts of thiophene free benzene alcohol having less than four carbon atoms in and 64 parts of methyl alcohol are added to this an anhydrous mixture of benzene and the same 35 solution, the solution is then reduced with a alcohol to form the corresponding a 20 compound sodium amalgam containing 0.1% (by weight) and to precipitate the anhydrous peroxide, the sodium at a temperature of 25° C., the reduction molar ratio of benzene to alcohol being not less being continued until 46 parts of sodium has re than about 0:1, the molar ratio of alcohol in acted. The azo benzene solution, originally deep cluding alcohol present as alcoholate to the A0 red, becomes straw yellow as the reduction re hydrazo compound being not more than about action is completed. After separation of the re 2:1, and the proportion of benzene being sufficient sulting hydrazo benzene solution from the dis to maintain the hydrazo and azo compounds in charged amalgam, oxygen is passed into the . solution, hydrazo benzene solution until 32 parts are ab 2. In the production of anhydrous alkali metal 45 sorbed. 78 parts of anhydrous sodium peroxide peroxides, the improvement which comprises oxi is precipitated and separated from the benzene dizing an hydrazo compound in the presence of alcohol mixture by filtration. The remaining an alcoholate of the alkali metal and of an al azobenzene solution, again deep red, is again re cohol having less than four carbon atoms in an duced with sodium amalgam, the process being anhydrous mixture of benzene and the same al 50 repeated as described. cohol to form the corresponding a Zo compound Eacample II and to precipitate the anhydrous peroxide, the molar ratio of benzene to alcohol being not less 5 5 210 parts of p-azotoluene are dissolved in 4000 than about 10:1, the molar ratio of alcohol in parts of thiophene free benzene and 92 parts of cluding alcohol present as alcoholate to the 55 ethyl alcohol are added to this solution.