July 14, 1964 ' G. N. TYSON, JR 3,140,582 ROCKET PROPULSION METHOD USING BORON AND NITROGEN COMPOUNDS Filed April 14, 1959 Ger'g .Tyson Jr. INVENTOR. I", u .12) ATTORNEYS 3,l4,582 Patented July 14,, 1964 2 The nitrogen containing compound and the boron con 3,140,582 taining compound are reacted in such proportions that all ROCKET PROPULSION METHOD USING BORON of the nitrogen and all of the boron react to produce AND NOGEN COMPOUNDS boron nitride, the carbon is released as elemental carbon George N. Tyson, Jr., Claremont, Calif., assignor to Olin Mathieson Chemical Corporation, a corporation of and large volumes of hydrogen gas are produced. Virginia Nitrogen containing compounds which can be employed Filed Apr. 14, 1959, Ser. No. 806,396 as reactants include the saturated hydronitrogens such 20 Claims. (Cl. 60-354) as ammonia, hydrazine, triazane, tetrazane; the unsaturated hydronitrogens such as diimide, triazene, tetrazene, iso This invention relates to a method for producing large 10 tetrazene, ammonium azide, hydrazine azide, and hydra volumes of hot gases in a short period of time, which zoic acid; alkyl hydrazines such as methyl hydrazine, un large volumes of hot gases are useful for many purposes symmetrical dimethyl hydrazine, ethyl hydrazine, unsym including imparting thrust to jet propelled devices such metrical diethyl hydrazine; alkylamines including mixed al as rockets. kylamines such as methylamine, dimethylamine, trimeth Jet propelled devices are essentially of two types: those 15 ylamine, ethylamine, diethylamine, triethylarnine, methyl which depend upon an external source for a portion of ethyl amine, n-propylamine, isopropylamine, di-n-propyl the propellant, and those in which the propellant is en amine, tri-n-propylamine, methyl propyl amine, ethyl prop tirely contained within the device. Such latter devices are ylamine, and the like; alkylene diamines such as ethylene conventionally called pure rockets. This invention will diamine and trimethylene diamine; hydrocyanic acid, alkyl be further described in relation to pure rockets and their 20 nitriles such as acetonitrile and propionitrile, and alkenyl operation. nitriles such as acrylonitrile; alkyl azides such as methyl One of the most important characteristics of a rocket azide, ethyl azide and propyl azide; cyanogens such as propellant system is its performance index or speci?c im cyanogen, isocyanogen and isocyanogen tetrazide; carbon pulse. This is the amount of thrust in pounds that can subnitride; cyanamide, ammonium cyanamide, and alkyl be obtained per pound of propellant consumed per sec 25 cynamides such as methyl cyanamide and ethyl cyan ond. Since the aim is to get as much thrust as possible amide, and dicyandiamide. Mixtures of the above nitro per pound of propellant burned, a high value for the gen containing compounds can also be employed as can speci?c impulse is desirable. their solutions in ammonia or hydrazine. isocyanogen Rocket propellants can be in the form of solids or in tetrazide, CZNM, melting point 89° C., can be prepared, for the form of liquids. Propellants consisting of a single 30 example, by the reaction of isocyanogen tetrabromide in liquid are termed monopropellants and include hydrogen acetone or absolute ethanol with sodium azide, activated peroxide and nitromethane. Propellants involving two by rubbing with a trace of N2H4-H2O and precipitated liquids are termed bipropellants and normally consist of from a little water with acetone, in water at 0° C. with a fuel, such as a hydrocarbon, ethyl alcohol-water or stirring, according to the method described in application ammonia and an oxidizer such as hydrogen peroxide or 35 Serial No. 806,210, of Christoph I. Grundmann et al. ?led liquid oxygen. Other oxidizer fuel combinations include of even date herewith, now US. Patent No. 2,990,412. nitric acid with aniline or furfuryl alcohol. These latter Boron containing compounds which can be employed combinations are termed hypergolic bipropellants since as reactants include boron hydrides such as diborane, tetra they react spontaneously upon admixture. borane, pentaborane-9 (B5H9), dihydropentaborane Hydrazine has also been used as a fuel component in (B5H11), decaborane; alkyl boranes such as trimethyl bipropellant systems in combination with oxidizers such borane, triethylborane and diethyl methyl borane; the as liquid oxygen, hydrogen peroxide, white or red fuming reaction products of diborane with ethylene disclosed in nitric acid, or liquid fluorine. It is spontaneously in?am application Serial No. 540,140, ?led October 12, 1955, mable with nitric acid and with ?uorine. The spec?c of Weilmunester et al.; the reaction products of diborane impulse of hydrazine when burned with liquid oxygen with acetylene disclosed in application Serial No. 514,122, varies from 257 to 264 pound-seconds per pound at 300 45 ?led June 8, 1955 of Stange et al.; the reaction products p.s.i.a. for various fuel-oxygen ratios, the value being of diborane with 3 to 5 carbon atom acetylenes or dienes higher in the presence of excess fuel, and when ?uorine disclosed in application Serial No. 533,944, ?led Septem is used as the oxidizer, the speci?c impulse at 300 p.s.i.a. ber 13, 1955 of Weilmuenster et al.; monoethyltetraborane is about 298 pound-seconds per pound. disclosed in application Serial No. 505,706, ?led May 3, It has been proposed to employ the boron hydrides in 50 1955 of Faust et al.; monoalkyl pentaboranes such as cluding diborane, tetraborane and the pentaboranes as monomethylpentaborane - 9, monoethylpentaborane - 9, fuel components in bipropellant systems wherein liquid mono-n-propylpentabcrane-9 disclosed in application Se oxygen is the oxidizer. Such systems supply high calcu rial No. 497,408, ?led March 28, 1955, now US. Patent lated speci?c impulses of about 290 pound-seconds per No. 3,038,012 of Altwicker et al. and application Serial pound at 300 p.s.i.a. 55 No. 501,742, ?led April 15, 1955 of Chiras et al.; dialkyl Both hydrazine and the boron hydrides are strong re pentaboranes such as diethylpentaborane-9 disclosed in ducing agents, reacting vigorously with a variety of oxi application Serial No. 540,145, ?led October 12, 1955 of dizers. It has now been discovered that, surprisingly, Paustian et al., and now abandoned; the mono- di- and nitrogen containing compounds which are normally con trialkyldecaboranes such as monomethyldecaborane, di sidered to be reducing agents react with boron containing 60 methyldecaboraue, ethyldecaborane, diethyldecaborane, compounds which are also normally considered to be re triethyldecaborane disclosed in application Serial No. ducing agents. Moreover, it has been found that the re 497,407, ?led March 28, 1955, now US. Patent No. actions produce a very high specific impulse, of the order 2,999,117, of Altwicker et al.; reaction products of acet of 300 pound-seconds per pound at 300 p.s.i.a. ylenic hydrocarbons with decaborane and alkyldecabo— Thus large volumes of hot gases are produced accord ranes such as those disclosed in application Serial No. ing to the present invention by reacting a nitrogen con 741,976, ?led June 13, 1958 of Ager, Jr. et al., now taining compound composed only of nitrogen, hydrogen abandoned, and application Serial No. 779,788, ?led De and carbon with a boron containing compound composed cember 11, 1958 of Clark et al., now U.S. Patent No. only of ‘boron, hydrogen and carbon; providing that hydro 3,092,664. Mixtures of the above boron containing com gen is present in at least one of the reactants and providing pounds can also be employed as can solutions of the that carbon is present in at least one of the reactants. solid compounds in the liquid compounds. 3,140,582 9 A The nitrogen containing compounds and the boron con tially opened until reaction is established at which time taining compounds described above react to produce very they are fully opened. After start-up, the flow ratio of ?nely divided solid boron nitride, very ?nely divided car~ nitrogen containing compound to boron containing com bon, and large volumes of hydrogen gas. The following pound is adjusted to be approximately stoichiometric for are representative equationsillustrative of the reactions U1 the reaction of all of the boron in the latter with all of which take place: the nitrogen in the former to form boron nitride, BN. Liquid propellants mostly are reacted in the tempera ture range of 2000° F. to 5500° F. at pressures between 300 and 1500° p.s.i.a. The reaction pressure, as stated previously, can be controlled by the rate of ?ow of the propellants. The nitrogen containing compounds and the boron containing compounds described above react at relatively. high, temperatures of 4500° to 5000.0 F. at these pressures. For rocket engines designed for rela Some of the above nitrogen containing compounds re 15 tively long periods of sustained operating duration, the act spontaneously with the boron containing compounds engine can be cooled, for example by a regenerative cool so that care must be used in their handling. ing system using one of the bipropellant fuel elements or In addition to the extremely high speci?c impulses pro another relatively inert ?uid as the coolant ?owing through duced by the above reactions the use of the above nitrogen a jacket surrounding the reaction chamber. containing compounds and the above boron containing FIGURE 2 of the drawing. shows a modi?cation of compounds as bipropellants for rockets is especially ad FIGURE 1 wherein tank 6 and line 4 are surrounded vantageous since in most instances both of the fuel com by heating coil 12. The modi?cation shown in FIGURE ponents are either normally liquid or can be dissolved 2 permits the use of low melting point solid boranes in a fuel component which is normally liquid.