2,874,164 United States Patent 0 Patented Feb. 17, 1959

1 2 Another object of the present invention is to provide such processes in which the amount of a speci?c diluent 2,874,164 to e?iciently suppress combustion can be readily deter PREVENTION OF COMBUSTION 1N mine for a given system containing ?lms of known ozo OXYGEN-OZONE MIXTURES nides or ozonide decomposition products having ascer tainable ignition temperatures. Victor A. Hann, St. Davids, Pa., assignor to The Welsbach Other and further objects of the present invention will Corporation, Philadelphia, Pa., a corporation of Dela appear from the following description of illustrative em ware bodiments of the same. No Drawing. Application August 21, 1956 10 The processes of the present invention are capable of Serial No. 605,423 various procedural embodiments without departing from the present inventive concept and reference should there 8 Claims. (Cl. 260—339) fore be had to the appended claims to determine the scope of this invention. _ This invention relates to processes for the prevention 15 As noted above, the ?lms containing ozonides or ozo of combustion in oxygen-ozone mixtures and more par nide decomposition products in the presence of an oxy ticularly to the prevention of combustion in systems con gen'ozone atmosphere act like a combustible mixture taminated by ozonides or their decomposition products although there is apparently insu?icient organic matter formed during the oxidation of unsaturated organic ma in the gas phase to constitute a combustible mixture. terials by oxygen-ozone mixtures and is a continuation 20 These ?lms contain ascertainable proportions of ozonides in-part of my co-pending application Serial No. 508,807, or ozonide decomposition products. The ozonide por‘ ?led May 16, 1955, now abandoned, under the title “Pre tion of the ?lm may be any ozonide produced by the vention of Combustion in Oxygen-Ozone Mixtures.” action of ozone upon an unsaturated organic compound‘. It is well known in the art that the ef?ciency of an I have found that the proportion of ozonide necessary ozonator is increased almost a hundred percent when to produce hazardous conditions is not ?xed but varies oxygen is used in the production of ozone as opposed to with the speci?c ozonide and the percentage of oxygen the production of ozone using air. This increased e?‘i in the gas phase over the .?lm. These ?lms develop in ciency is obtained without increase of the electrical en~ ozone reactions and recycling systems either by the ?lms ergy supplied to the ozonator. It is also well known forming on surfaces in the reactor itself or from spray‘ that mixtures containing more than 20% oxygen plus 30 or carry-over in the gas stream. certain inert diluents (N2, CO2) when fed to an ozonator The hazardous nature of these ?lms was not known will increase the et?ciency of production. The use of prior to my discovery thereof and the suppression of oxygen to generate oxygen-ozone mixtures is unexpect combustion in such ?lms by limited dilution of the oxygen in the oxygen-ozone mixture by certain gaseous diluents edly. potentially hazardous when the oxygen-ozone mix 35 tures are subsequently used to oxidize unsaturated or is most unexpected. ganic materials. In the oxidation of unsaturated or The present invention does not propose such dilution ganic materials which contain ethylenic carbon-carbon as to bring the oxygen-ozone mixture below the. point. double bonds with oxygen-ozone mixture ?lms contain Where there is no longer enough oxygen to support com bustion but, depending upon the ozonide involved and ing ozonides of ozonide decomposition products which 40 are products resulting from the reaction of ozone with the system in which it is found, the present invention said double bonds are formed in the system and I have proposes dilution of the oxygen to approximately air found that these ?lms and the oxygen-ozone atmosphere proportions, say approximately 20 to 50% oxygen, at surrounding them act very much like a combustible mix least for certain ozonides, to eliminate combustion.v In ture although there appears to be far too little organic a dilution of this degree sufficient oxygen is present to vapor to form a combustible mixture. An extremely support normal combustion but combustion is not sup rapid combustion takes place when these ozonides or ported in the ozonide ?lms here under consideration. ozonide decomposition products in an oxygen-ozone at The phenomenon with which the present invention is mosphere are triggered by a spark or other suitable means concerned acts as if a combustible mixture were present and in an enclosed system can easily produce a violent but there is too little organic material in the gas phase explosion. I do not know with certainty why these ?lms to constitute a combustible mixture. This is demon in an oxygen-ozone atmosphere react in this way and strated by experimental observations in which a ?lm of so will not burden the description-of theprcsent invention oleic acid on a cool surface in pure oxygen will not sup with reasons for this observed phenomenon because of port combustion. No combustible mixture is here pres the possibility that such reasons may be erroneous. ent since the gas phase is substantially pure oxygen. A I have found most unexpectedly that combustion of ?lm of oleic acid ozonide, on the other hand, on a cool these ?lms in an oxygen-ozone atmosphere can be in surface in pure oxygen will readily support combustion. hibited by the presence in the oxygen-ozone atmosphere A combustible mixture is again not present since only of certain gaseous diluents. The amount .of diluent em substantially pure oxygen is present in the gas phase. It ployed will vary with the diluent itself, with the ozonide is further observed that a ?lm of oleic acid ozonide on or ozonide decomposition product in the ?lm, and will 60 a cool surface in air willgnot support combustion. No depend upon the ignition temperature of the ozonide or combustible mixture is present. It has'been pointed out above that the amount of dil ozonide decomposition product in the system and upon uent required to suppress combustion will depend in part the geometry of the system. The amount and speci?c upon the geometry of the particular system involved. diluent may be selected in accordance with the ozonide Factors such as temperature, ozone concentratiomdililent or ozonide decomposition product present and examples involved, speci?c ozonide involved, type of ignition source, of suitable diluents will be described below. and geometry of the system affect the concentration 'of It is accordingly an object of the present invention diluent required to prevent ignition of the oxygen-ozone to provide novel processes for the prevention of combus ?lm system. It is manifestly impractical tov give' ex tion in oxygen-ozone mixtures including ?lms of ozonides amples of all ozonides under all possible" conditions. or ozonide decomposition products in which the oxygen However representative examples aregiven below to de ozone mixture is diluted with certain gaseous diluents. scribe the present invention. " ‘ ' 2,874,164 3 4 The temperatures which are given in the examples be and helium may ‘be employed as the gaseous diluent. It low are the “ignition temperatures” determined by the is also to be understood that known types of ozonators, particular ozonide and system in which it occurs as well known types of oxygen purifying systems and apparatus, as by the other factors discussed above. This “ignition and known systems for cleaning up the spent oxygen temperature” is not a characteristic property of the ozo diluent gas mixtures may be employed all within the nide or ozonide decomposition product in the ?lm and de scope of the present concept. pends upon the properties of the particular environment As an example of the present invention using helium, in question. an explosion was caused by triggering ignition with a In a characteristic example of the processes of the pres spark of the ?lms and vapors of the ozonide of tall oil ent invention, explosion was caused by triggering ignition 10 fatty acids in an atmosphere of approximately 2% ozone with a spark of ?lms of oleic acid ozonide in an atmos and 98% oxygen. When the oxygen concentration was phere of approximately 3% ozone, 42% oxygen and reduced to approximately 79% by diluting with helium, 55% CO2 when the temperature of the ozonide was raised no explosion could be triggered by means of a spark un to approximately 180° C. When the oxygen concentra der exactly the same conditions. tion was diluted to 37% and the CO2 concentration was 15 In another example of the processes of the present in raised to 60% no explosion could be triggered by means vention, explosion was caused by triggering ignition with of a spark under exactly the same conditions. a spark of the ?lms and vapors oleic acid ozonide in an In another characteristic example of the processes of atmosphere of approximately 2% ozone and 98% oxy the present invention, explosion was caused ‘by triggering gen. When the oxygen concentration was reduced to ap ignition with a spark of ?lms of oleic acid ozonide in an 20 proximately 25% by diluting with argon, no explosion atmosphere of 100% oxygen when the ozonide Was ap could be triggered by means of a spark under exactly the proximately at room temperature. When the oxygen was same conditions. diluted with approximately 50% carbon dioxide, no ex~ It should now be apparent to one skilled in the art plosion could be triggered by means of a spark under ex that by the present invention I have provided novel proc actly the same conditions; 25 esses for the prevention of combustion in oxygen-ozone In another example of the processes of the present mixtures which in every way satisfy the several objectives invention, explosion was caused ‘by triggering ignition described above. with a- spark of ?lms of oleic acid ozonide in an atmos- , Changes in or modi?cations to the above described il phere of 2% ozone, and 98% oxygen. When the oxy lustrative embodiments of the present invention may now gen was diluted to approximately 42% with carbon di 30 be apparent without departing vfrom the present inven oxide, no explosion could be triggered by means of a tive concept and reference should therefore be had to spark under exactly the same conditions. the appended claims to determine the scope of this inven In the above example and others given here, the ozone tion. - concentration has been purposely held constant to about What is claimed is: ' 1 to 3%. In employing known ozonators for use in the 1. In a process for inhibiting combustion in a system present invention, the ozone concentration is not expected containing gaseous ozone and oxygen and ?lms of prod to exceed the range of 0.5 to 5%. . ucts resulting from the reaction of ozone with an acid se In another representative situation in accordance with lected from the group consisting of oleic acid, linoleic the present invention explosions were triggered by a spark acid, mixtures of oleic acid and linoleic acid and alpha in a system which included a-pinene ozonide in a 1% 40 pinene, the steps of adding a diluent selected from the ozone-oxygen-carbon dioxide atmosphere. Less violent group consisting of carbon dioxide, argon and helium to explosions occurred when the carbon dioxide component the gaseous oxygen so that the oxygen comprises 20-80 of the atmosphere was increased in the range of 50-65% weight percent of the gaseous mixture, then ozonizing said and no explosions could be triggered when the concen oxygen-containing gas to an ozone concentration of ap tration of carbon dioxide was 70% or more of the at» proximately '1-3 weight percent in a conventional ozo mosphere. ‘ nizer discharge, and then ‘bringing the ozone-containing Several methods may be employed for adding the in~ gaseous mixture in contact with said ?lms. ert diluent gas to the oxygen-ozone mixture in accord 2. In a process for inhibiting combustion in a system ance with the present invention. In one procedure, sub containing gaseous ozone and oxygen and ?lms of organic stantially pure oxygen is passed through the ozone gen compounds resulting from the reaction of ozone with an erator, forming a mixture of ozone and oxygen, which acid selected from the group consisting of oleic acid, is then diluted by addition in proper amount of a gas linoleic acid, mixtures of oleic acid and linoleicv acid and selected from the group of carbon dioxide, argon, and alpha-pinene, the steps of adding carbon dioxide to the helium. This gaseous mixture is then passed into a suit~ gaseous oxygen so that ‘the oxygen comprises 30-42 weight percent of the gaseous‘mixture, then ozonizing able reactor and the ozonization reaction occurs strip 55 ping the ozone from the gas mixture. If carbon diox said oxygen-containing gas to an ozone concentration of ide is the diluent the oxygen-diluent mixture is then passed approximately 1-3 weight percent in a conventional to a suitable scrubber or condenser where the diluent is ozonizer discharge, and then bringing the ozone-contain separated from the oxygen and the oxygen is then com i-ng gaseous mixture in contact with said ?lms. 3. In a process for inhibiting combustion in a system ' pressed and puri?ed as may be necessary and recycled to 60 the ozonator. containing gaseous ozone and oxygen and ?lms result In another procedure for supplying the diluent gas to ing from the reaction of ozone'witlr an acid selected from the oxygen-ozone mixture a stream of substantially ‘pure the group consisting of oleic acid, linoleic acid, mixtures oxygen is diluted with‘ enough carbon dioxide to suppress of oleic acid and linoleic acid and alphaipinene, the steps of adding helium to the gaseous oxygen so that the oxy subsequent ignition and this gaseous mixture is then passed 65 through the ozonators to form a small concentration of gen comprises approximately 79 weight percent of the ozone therein. The gaseous ‘mixture with ozone is then gaseous mixture, then ‘ozonizing said oxygen-containing passed through a reaction system in which the ozone is gas to an ozone concentration of approximately -l-3 stripped from the oxygen-carbon dioxide mixture. and the weight percent in a conventional ozonizer discharge, and then bringing the ozone-containing gaseous mixture in stripped oxygen-carbon dioxide mixture is then puri?ed, 70 as may be required, and returned to the ozonator as a re contact with said ?lms. cycled gas, ,any' loss of carbon dioxide being adjusted be 4. Ina process for inhibiting combustion ‘in a system fore recycling to the ozonators. containing gaseous ozone. and oxygen and ?lms of or It is tof be understood, of‘course, that in place of the ganic compounds resulting from the reaction of ozone carbon ‘dioxide mentioned in the paragraph ‘above argon 75 with an acid-selected from the group consisting of‘oleic 2,874,164 .5 6 acid, linoleic acid, mixtures of oleic acid and linoleic compounds resulting from the reaction of ozone with an acid and alpha-pinene, the steps of adding argon to the acid selected from the group consisting of oleic acid, gaseous oxygen so that the oxygen comprises approxi linoleic acid, mixtures of oleic acid and linoleic acid and mately 25 weight percent of the gaseous mixture, then alpha-pinene, the steps of adding helium to gaseous ozonizing said oxygen-containing gas to an ozone con ozonized oxygen so that oxygen comprises approximate centration of approximately 1-3 weight percent in a con ly 79 weight percent of the mixture, and then bringing ventional ozonizer discharge, and then bringing the ozone the ozone-containing gaseous mixture in contact with said containing gaseous mixture in contact with said ?lms. ?lms. 5. In a process for inhibiting combustion in a system 8. In a process for inhibiting combustion in a system containing gaseous ozone and oxygen and ?lms of or 10 containing gaseous ozone and oxygen and ?lms of organic ganic compounds resulting from the reaction of ozone compounds resulting from the reaction of ozone with an with an acid selected from the group consisting of oleic acid selected from the group consisting of oleic acid, acid, linoleic acid, mixtures of oleic acid and linoleic linoleic acid, mixtures of oleic acid and linoleic acid and acid and alpha-pinene, the steps of adding a diluent se alpha-pinene, the steps of adding argon to gaseous lected from the group consisting of carbon dioxide, ar 15 ozonized oxygen so that oxygen comprises approximately gon and helium to gaseous ozonized oxygen so that oxy 25 weight percent of the mixture, and then bringing the gen comprises 20-80 weight percent of the mixture, and oizoneacontaining gaseous mixture in contact with said then bringing the ozone-containing gaseous mixture in ? ms. contact with said ?lms. References Cited in the ?le of this patent 6. In a process for inhibiting combustion in a system 20 containing gaseous ozone and oxygen and ?lms of or UNITED STATES PATENTS ganic compounds resulting from the reaction of ozone with 2,083,572 McKee ______June 15, 1937 an acid selected from the group consisting of oleic acid, linoleic acid, mixtures of oleic acid and linoleic acid and FOREIGN PATENTS alpha-pinene, the steps of adding carbon dioxide to gase 25 234,163 Great Britain ______May 12, 1925 ous ozonized oxygen so that oxygen comprises 30-42 weight percent of the mixture and then bringing the OTHER REFERENCES gage-containing gaseous mixture in contact with said Yeaw et al.: Chem. Abstract, vol. 33, page 5158 (1939). 7. 'In a process for inhibiting combustion in a system 30 Taylor: Inorganic and Theoretical Chem., page 615, containing gaseous ozone and oxygen and ?lms of organic W. Heinemann Ltd., London, 9th ed. (1952). UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,874,164 February 17, 1959

Victor A. Hann It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below. Column 1, line 39, for "of ozonide" read - or ozonide --; column 2, lines 3 and 4, for "determine'1 re'ad -- determined —-. Signed and sealed this Qtb day of June 1959.

( SEAL) Attest: KARL H. AXLINE , ROBERT C. WATSON Attesting O?icer Commissioner of Patents UNITED STATES PATENT OFFICE @ERTIFICATE OF CORRECTION Patent No" 2 ,874 ,164 February 1'7 , 1959

Victor A. Harm It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below. Column 1, line 39, for "of ozonide" read me or ozonide M; column 2, lines 3 and 4, for "determine" read w’ determined w. Signed and sealed this 9th day of June 1959.

( SEAL) Attest: KARL Ha AXLINE v ROBERT C. WATSON Attesting O?icer Commissioner of Patents