Patented Sept. 7, 1937 2,092,322 UNITED STATES PATENT of FICE 2,092,322 PROCESS FOR THE PRODUCTION OF OR GANC PEROXDES Franz Rudolf Moser, Amsterdam, Netherlands, assignor to Shell Development Company, San Francisco, Calif., a corporation of Delaware No Drawing. Application March 18, 1935, Serial No. 11,667. In the Netherlands September 14, 1934 12 Claims. (C. 260-16) This invention relates to processes of manu the latter "wetted' whereby its explosiveness is facturing organic peroxides and deals, particu greatly reduced. larly, with a novel, simplified method for eco My invention may be practiced with any suit nomically producing peroxides from ketones, able organic compound which forms peroxides 5 aldehydes, and the like. It is also concerned with by reaction with hydrogen peroxide. Suitable the production of new compositions of matter organic compounds which may be used as start comprising organic peroxides suitably 'wetted' ing material are, for example: aliphatic ketones, to reduce their explosiveness and make them of which acetone, methyl ethyl ketone, diethyl capable of safe handling, transportation and ketone, methyl isopropyl ketone, methyl second storage. ary butyl ketone, methyl tertiary butyl ketone 10 O The preparation of organic peroxides by the are typical: aromatic ketones such as aceto reaction of hydrogen peroxide upon ketones, phenone, benzo-phenone, benzyl-ethyl ketone, aldehydes, dialkyl sulfates, acid anhydrides, acid benzylnaphthyl ketone, and homologues and chlorides and the like is well known. Particu analogues thereof; aliphatic aldehydes, such as 5 larly with ketones and aldehydes, the reaction has formaldehyde, acetaldehyde, propionaldehyde, 15 been carried out in the presence of strong acids, isobutylaldehyde, methyl ethyl acetaldehyde, such as hydrochloric and sulfuric acids, while trimethyl acetaldehyde, and the like; aromatic maintaining a low temperature. So-called di aldehydes, as benzaldehyde, toluic aldehydes, meric acetone peroxide has also been prepared cuminol, naphthaldehyde, etc.; and aldehyde 20 by reacting Caro's acid (H2SOs) with a solution of ketone, including both aliphatic and aromatic 20 acetone in ether. All these prior procedures, in compounds as pyroracemic aldehyde, isopropyl Wolving as they do the separate preparation and glyoxal, formyl acetone, laevulinic aldehyde, addition of hydrogen peroxide or the relatively benzoyl-propia-aldehyde, and the like. Poly rare Caro's acid, are cumbersome and expensive. ketonic and polyaldehydic compounds corre 25 It has now been found, and it is on this dis sponding to the above may also be used, for ex 2. covery that the present invention is based, that ample, diacetyl, acetyl propionyl, acetyl acetone, for the manufacture of organic peroxides, it is acetonyl acetyl acetone, glyoxal, succinic dialde not necessary to resort to a separate operation of hyde, mesoxalic dialdehyde, benzoyl-acetyl, isolating hydrogen peroxide or of preparing phenyl - methyl-triketone. Furthermore, such 30 Caro's acid, but that it is entirely feasible and compounds may contain substituents as halogen 30 less expensive, to use a solution of persulfuric (as in chloral, monochloracetone and the like) acid or of a persulfate, the latterpreferably acidi nitro, i. e. NO2, groups (as m-nitro benzaldehyde, fied, as Starting material. s etc.) and the like. The process of my invention comprises sub Such starting materials may be in the form of 35 jecting a solution of persulfuric acid or a, prefer the chemical individuals, or mixtures thereof, or 35 ably acidified, solution of a persulfate to a hydro may be admixed with hydrocarbons or other ma-. lytic treatment, such, for example, as bringing terials which may be considered inert in the the solution to an elevated temperature for a process. Thus the crude mixtures obtained in short time. By this hydrolysis free hydrogen the preparation of such compounds, as, for ex 40 peroxide, and possible HaSO5 are formed in the ample, the aldehyde and/or ketone containing solution. Without removing these hydrolysis mixtures resulting from the vapor phase oxida products the at least partially hydrolyzed per tion of petroleum fractions, and the like, may be used. sulfate radical containing solution is reacted with The hydrolysis of the persulfuric acid solution 45 the organic compound from which it is desired to may be carried out in any convenient manner. manufacture the peroxide. This reaction is pref In place of persulfuric acid any soluble persul erably carried out at a low temperature after fate, such as sodium, potassium, calcium and the which the peroxide formed is separated from the like persulfates, may be used, in which case a reaction mixture and the latter may again be relatively strong acid is preferably added to the 50 used for the further preparation of peroxide. solution before hydrolysis. Short periods of heat 50 Although any conventional method may be used ing at about 100° C. are usually sufficient to effect for recovering the peroxide from the reacted mix the desired hydrolysis. If desired, the hydrolysis ture, I prefer to make the separation by extrac may be carried Out in the presence of the usual tion with a suitable solvent which may then be stabilizers for hydrogen peroxide such as urea, 55 incompletely removed from the peroxide leaving and its derivatives, acetanilide, organic amido 55 2 2,092,822 derivatives and the like. The hydrolysis treat hazard highly volatile fractions are preferably ment is a very important feature of Xiny process avoided and those boiling above about 100° C. are as without it persulfuric acid solutions react only given preference. To effect this stabilization of extremely slowly, if at all, with many of the the peroxide only about 10 to 50% of wetting organic compounds which readily form peroxides agent, based on the weight of the final product, therewith, by my method. After the hydrolysis it need be used. The wetting agent may be added may be desirable to add more acid to the mixture, to the peroxide after its separation from the re as it is highly advantageous. to maintain a con action mixture, or, as has already been men dition of strong acidity during the subsequent tioned, may be used as the extracting medium for reaction with the organic compound to be oxi the peroxide and then incompletely separated 10 dized, as peroxide formation is considerably ac therefron by vacuum distillation. In either case celerated by the presence of free acidi. a thorough intimate dispersion of the wetting For the purpose of affording a clear under agent throughout 'the peroxide mass is highly standing of my invention it will be described with desirable. more particular reference to the manufacture of The following example illustrates in greater 5 15 acetone peroxide. It will be understood, however, detail one method of preparing acetone peroxide that I am not to be limited thereto as this is only by my invention: one example of the possible applications of a A perSulfuric acid solution containing about process which may be used to prepare a wide 13% H2S2O8 which had been prepared by elec variety of other organic peroxides. trolysis of a 50% solution of sulfuric acid, was 20 20 The reaction of acetone with a hydrolized per exposed for one minute at 100° C. to a hydrolytic sulfuric acid or persulfate solution, prepared as treatment. It was then cooled to about -20° C. described above, is preferably carried out, as is and its active oxygen content determined by an also the case with the other starting materials alysis. The theoretical quantity of acetone corre 25 given in the list of examples, below about Zero Sponding to the active oxygen so determined was 25 degrees centigrade. The reagents may be con then added a little at a time while the mixture tacted in any suitable manner, thus either batch, was stirred vigorously. On completion of the ace intermittent or continuous methods of operation tone addition, the mixture was allowed to react may be used. One batch method of operation for an additional 15 minutes. The acetone perox 30 comprises adding the theoretical quantity of ace ide formed was then extracted with benzene. The 30 tone in small doses to the strongly cooled per benzene was removed by evaporation on a water sulfuric acid hydrolysis product while continu bath after which gas oil equivalent to about 40% ally stirring the mixture. In general, only a of the Weight of the acetone peroxide was added short time is required for the reaction when the yielding a product which could be handled and 35 presence of free acid in the reaction mixture is stored with greatly reduced risk of explosion. assured as by the previously described method of In addition to the use of these products as perSulfuric acid treatment. primers for Diesel engine fuels and as bleaching The recovery of the organic peroxide may be agents for flour, which have already been men carried out in any suitable conventional manner. tioned, they may also be employed as ignition aids 40 Where a water insoluble solid peroxide such as for other types of motor fuels, such as gasolines, 40 acetone peroxide is being produced, it may be etc., and for other types of bleaching as in the separated by filtration of the reaction mixture. bleaching of textiles, paper pulp, and the like. Alternatively extraction methods may be used, They are further useful as intermediates in the suitable solvents being ether, gasoline, benzene, preparation of pharmaceuticals and other syn 45 gas oil, and the like. The solvent employed thetic organic products, as well as oxidizing agents 45 should, preferably, be inert with respect to the for promoting the drying of paint and varnish reaction mixture which mainly contains sulfuric films, etc. acid which can be used again for the preparation While I have in the foregoing described in some of more organic peroxide. Thus where a petro detail the preferred embodiment of my invention 50 leum fraction is used, for example, it should be and Some variants thereof, it will be understood 50 One which has been subjected to a thorough acid that this is only for the purpose of making the refining. Where the contemplated use of the invention more clear and that the invention is organic peroxide demands a very pure product, not to be regarded as limited to the details of as for example, in the bleaching of flour, and the operation described, nor is it dependent upon the 55 like, volatile solvents such as gasoline or lower Soundness or accuracy of the theories which I 55 boiling hydrocarbon fractions, benzene and the have advanced as to the reasons for the ad like, which may readily be removed by distillation, vantageous results attained. On the other hand, may be used. On the other hand, the use of the invention is to be regarded as limited only higher boiling extractants offers particular ad by the terms of the accompanying claims, in 60 vantage where it is not necessary to apply the which it is my intention to claim all novelty in 60 peroxide in such a high degree of purity. Thus, herent therein as broadly as is possible in view for instance, where the peroxide is to be used for of the prior art. improving the ignition quality of Diesel engine I claim as my invention: fuels, gas oil may very advantageously be used 1. A process of producing an organic peroxide 65 as the extractant. In such case it is unnecessary 85 to recover the peroxide from the Sovent since which comprises reacting a member of the class the extract representing, for example, a 7% per consisting of ketones and aldehydes with a per oxide solution may be directly blended with the sulfate radical containing solution which has been fuel to be treated, Subjected to a hydrolytic treatment. Such high boiling petroleum fractions may also 2. A process of producing an organic peroxide 70 70 be used to reduce the explosiveness of the per which compriseS reacting a member of the class oxide, thus acetone peroxide wetted with gas consisting of ketones and aldehydes with a hy oil, for example, is much more stable than the drolyzed persulfate solution. peroxide in a dry condition. Other hydrocarbons 3. A process of producing an organic peroxide 75 may be similarly used but because of their fire which comprises reacting a member of the class 75 2,092,822 3 consisting of ketones and aldehydes with a hy taining Solution, adding thereto a member of the drolyzed perSulfuric acid Solution. class consisting of ketones and aldehydes and sub

4. A process of producing a ketone peroxide sequently separating an organic peroxide there which comprises reacting a ketone with a hy from. drolyzed perSulfate radical containing solution. 10. A process of producing an organic peroxide 5. A process of producing acetone peroxide which comprises reacting a member of the class which comprises reacting acetone with a persul consisting of ketones and aldehydes with a hy fate radical containing Solution which has been drolyzed persulfate radical containing solution at subjected to at least partial hydrolysis. a temperature below about zero degrees centi 6. A process of producing an aldehyde peroxide grade. 10 O which comprises reacting an aldehyde With an ll. A process of producing an organic peroxide at least partially hydrolyzed persulfate radical which comprises reacting a member of the class containing solution. consisting of ketones and aldehydes with an at 7. A process of producing an organic peroxide least partially hydrolyzed persulfate radical con 5 which comprises hydrolyzing a persulfate radical taining Solution in the presence of a hydrogen 5 containing Solution, adding thereto a member of peroxide stabilizer. the class consisting of ketones and aldehydes and 12. A process of producing an organic peroxide Subsequently Separating an organic peroxide which comprises reacting a member of the class therefron. consisting of ketones and aldehydes With a per 20 8. A process of producing an organic peroxide Sulphate radical-containing Solution which has 20 which comprises reacting, in the presence of acid, been subjected to a hydrolytic treatment and sub a member of the class consisting of ketones and sequently separating an Organic peroxide there aldehydes with a hydrolyzed persulfate radical from by extraction with a Solvent for Said per containing Solution. oxide which is also capable of behaving as a sta 25 9. A process of producing an organic peroxide bilizing agent therefor. 25 which comprises heating a persulfate radical con FRANZ RUDOLF MOSER.