1 3,269,879 United States Patent 0 ICE Patented August 30, I966 1 2 ammonium nitrate, and substituted in said lattice inor 3,269,879 AMMONIUM SALT LATTICE WITH ISOMOR ganic salts isomorphously co-crystallizable therewith. PHOUSLY SUBSTITUTED INORGANIC SALTS These inorganic salts are sometimes hereinafter referred Manfred Stammler, Carmichael, and Wilfred G. Schmidt, to as substituent salts. Sacramento, Calif., assignors to Aerojet-General Corpo 5 The inorganic salts capable of undergoing cocrystalliza ration, Azusa, Calif., a corporation of Ohio tion with ammonium perchlorate to form isomorphous No Drawing. Filed Apr. 13, 1964, Ser. No. 359,511 compositions include those having the formula: 16 Claims. (Cl. 149—2) (1) Maxi: This invention relates to novel isomorphous ammonium w'herein M is an alkali or alkaline earth metal cation, perchlorate and ammonium nitrate compositions prepared or the ammonium (NH4) group, and has a valence nu by cocrystallization, having greater sensitivity to impact merically equal to “12"; and X is an anion selected from and lower decomposition temperature, and being especial the group consisting of chromate, iodate, periodate and ly useful in explosive compositions, and to the method of permanganate, and has a valence numerically equal to producing the same. 15 “a.” Subscripts “a” and “b” are small whole numbers An explosive in the broadest sense, is a material which, of from 1 to about 3. Compounds within the scope of under the in?uence of shock, decomposes rapidly and Formula I include sodium chromate, lithium iodate, potas spontaneously with evolution of large amounts of heat sium periodate, calcium permanganate, strontium chro and gas. The hot gases create extremely high pressure mate, magnesium iodate, barium chromate, ammonium if the explosive is set off in a con?ned space. Today, 20 chromate, ammonium periodate and ammonium perman explosives are used to perform many engineering feats ‘ganate. which would be physically or economically impossible Another class of compounds which can be effectively without their use. Many diiferent types of explosives cocrystallized with ammonium perchlorate are those hav ‘have been employed for these purposes. Explosives vary ing the formula: widely in their sensitivity and power. Ordinarily explo 25 sives are classi?ed in one of the following three catagories; (II) M'cX'd initiating explosives such as mercury fulminate and lead wherein M' is a thallium, silver or copper cation; the azide; high explosives such as cyclo-trimethylenetrinitra valence of M’ is equal numerically to “d”; X’ is an anion mine (RDX); and low explosives such as black powders. selected from the group consisting of perchlorate, chro The initiating explosives are quite sensitive materials mate, iodate, periodate and permanganate; and has a which can be made to explode by the application of ?re valence equal to “c.” Subscripts “c” and “d” are small or by means of a slight blow. Initiating explosives are integers, usually equal to 1, 2 or 3. Compounds of the generally used in primers and detonators. High explo type de?ned by Formula II include thallium perchlorate, sive materials are those capable of exploding with great silver iodate, copper periodate, silver chromate, thallium , violence when set oil by an explosive shock such as that 35 iodate, copper permanganate and silver perchlorate. which would be obtained by detonating a small amount The ammonium nitrate is cocrystallized with com of initiating explosive in contact with the high explosive. pounds of the formula: The low explosives diifer in their mode of decomposition from the other two types, in that they only burn, and thus (III) M"eX"; their action is less shattering. 40 wherein M" is a cation selected from the group consist The bulk of the explosives employed industrially in ing of silver, thallium, copper, or an alkali metal such the United States in mining and construction work is of as potassium, lithium or sodium. The valence of M" the high explosive type. However, many of the high ex numerically equals the value of “f.” In this formula, plosives commonly used, such as RDX, are relatively ex X" is an anion having a valence equal to “e” and is se pensive. ’Dherefore, lower cost ingredients for high ex lected from the group consisting of nitrate, permanganate plosive compositions are needed. Ammonium perchlo 45 and Z”O3 where Z" is halogen, preferably chlorine, rate and ammonium nitrate are well-known as oxidizer bromine or iodine; and “e” and “f” are integers of from materials for use in solid rocket propellants. However, 1 to about 3. The inorganic salts capable of being co these materials are relatively insensitive to impact, thus crystallized with ammonium nitrate and de?ned by For limiting their use in high explosive compositions. It has mula III, include silver nitrate, thallous nitrate, potassium now been found, however, that the sensitivity to impact 50 permanganate, potassium chlorate, potassium br'omate and of ammonium perchlorate and ammonium nitrate can be potassium iodate. increased to a level approximately corresponding to that In Table I there appears illustrative isomorphous com possessed by RDX. This has now been accomplished by positions within the scope of our invention. cocrystallizing ammonium perchlorate and ammonium TAB LE I nitrate with certain other inorganic salts. These cocrystal 55 lized salts are isomorphous in nature and possess greater Lattice substituent Salt sensitivity to impact. It is therefore an object of this invention to provide ammonium perchlorate and ammonium nitrate composi Amiéionium Perehlorate_ . Sodium Chromate. 0 Potassium Chromate. tions possessing substantially enhanced impact sensitivity. . Calcium Iodate. Still another object of this invention is to increase the low Potassium Periodate. _ Copper Permauganate. temperature decomposition rate of ammonium nitrate Thallium Perchlorate. and ammonium perchlorate. More speci?cally, it is an Silver Chromate. Potassium Iodate. object of this invention to provide novel impact sensitive Magnesium Periodate. compositions containing a lattice of ammonium perchlo Potassium Permanganate. Silver Nitrate. rate or ammonium nitrate and containing isomorphously Thallous Nitrate. substituted therein certain inorganic salts. These and Potassium Permanganate. Potassium Chlorate. other objects of this invention will become apparent from Potassium Bromate. the detailed description which follows. Potassium Iodate. . There has been found according to this invention novel impact sensitive compositions comprising a lattice selected The substituent inorganic salts are normally .present in from the group consisting of ammonium perchlorate and the isomorphous cocrystallized compositions in the 1 3,269,879 3 A. amount of from about 0.1 percent to about 10 percent Was obtained, the precipitate was ?ltered, dried, and by weight and more preferably ‘from about 0.5 percent screened, to obtain an isomorphous cocrystallized prod .to about 2 percent by weight, ‘based on the total weight uct. The product obtained by the above-described meth— of the cocrystallized product. The ?nal isomorphous od was analyzed for concentration of the inorganic salt cocrystallized product is in a single phase and has an chemically. The results are as follows: average particle size of from about 20 microns to about 700 microns. NH4C-lO4-CaOrO4—2.03 percent by weight CaCrO4 Normally, the cocrystallization is carried out by ?rst tfound. dissolving the ammonium perchlorate or ammonium ni EXAMPLE HI trate and the inorganic salt to be cocrystallized therewith 10 Cocrystallized ammonium perchlorate and in water, and thoroughly mixing the solution. At least potassium iodate some of the water is then removed by heating and/or A 490 gram sample of ammonium perchlorate was dis the application of reduced pressure until cocrystalliza solved in about 3 liters of water. The solution was poured tion occurs. Preferably, this ‘concentration procedure into a 3-neck ?ask provided with a stirrer, thermometer is carried out at a temperature of ‘from about 20° C. to 15 and a dropping funnel. A solution of 10 grams of potas about 100° C., and at a pressure of from about 0.01 to sium iodate in 500 ml. of water Was then slowly added about 1 atmospheres. to the aqueous ammonium perchlorate solution. "The The weight ratio of total salts to water in the aqueous vigorously stirred mixture was then concentrated at 50° solution prior to concentration may be varied over a C. under reduced pressure. When a thick slurry was wide range and is not critical. Generally there should 20 obtained, the precipitate was ?ltered, dried and screened, be initially present su?icient water to dissolve all of the to obtain an isomorphous cocrystallized product. The salts. It can be seen that the minimum amount of water product obtained by the above-described method was required for a given weight of salts will depend on the analyzed and ‘found to contain about two percent potas solubility of the salts and the mixing temperature being sium iodate. employed, and thus is readily ascertained by those skilled 25 EXAMPLE IV in the art. Ordinarily, the amount of water used will be somewhat in excess of the minimum amount, and will Cocrystallized ammonium perchlorate and be from 0.2 to about 20 times the weight of the total potassium periodate salts. While the foregoing discussion is limited to the A 490 gram sample of ammonium perchlorate was dis— use of water as to the solvent, it is to be understood that solved in about 3 liters of water. The solution was poured any substantially inert solvent in which the salts are at into a 3-neck ?ask provided with a stirrer, thermometer least somewhat soluble may be utilized. Illustrative of and a dropping funnel. A solution of 10 grams of potas other suitable solvents are the lower alkanols such as sium perchlorate in 500 of water was then slowly methanol and ethanol, and .the lower alkylene glycols added to the aqueous ammonium periodate solution. The such as ethylene glycol and propylene glycol. vigorously stirred mixture was then concentrated at 50° After concentration the product is recovered in con under reduced pressure. When a thick slurry was ob ventional manner by ?ltration, decantation and the like. tained, the precipitate was ?ltered, dried and screened, The following are illustrative examples demonstrating to obtain an isomorphous cocrystallized product. The the preparation of the isomorphous cocrystallized com~ product obtained by the above-described method was positions of this invention. These examples are provided analyzed for concentration of the inorganic salt chemi solely for the purpose of illustration and are not to be cally, and found to contain about 2 percent by weight regarded as limiting the scope of the invention in any of potassium perioda-te. way. In the examples the parts are by weight unless otherwise indicated. EXAMPLE V EXAMPLE I Cocrystallized ammonium perchlorate and 45 thallium perchlorate cocrystallized ammonium perchlorate and potassium permanganate A 490 gram sample of ammonium perchlorate was dis solved in about 3 liters of water. The solution was poured A 490 ‘grams sample of ammonium perchlorate was into a 3-neck ?ask provided with a stirrer, thermometer dissolved in about 3 liters of water. The solution was 50 and a dropping funnel. A solution of 10 grams of thal poured into a 3-neck ?ask provided with a stirrer, ther lium perchlorate in 500 ml. of water was then slowly mometer and a dropping funnel. A solution of 10 grams added to the aqueous ammonium perchlorate solution. of potassium permanganate in 500 ml. of water was The vigorously stirred mixture was then concentrated at then slowly added to the aqueous ammonium perchlorate 50° C. under reduced pressure. When a thick slurry solution. The vigorously stirred mixture was then con 55 was obtained, the precipitate was ?ltered, dried and centrated at 50° C. under reduced pressure. When a screened, to obtain an isomorphous cocrystallized prod thick slurry was obtained, the precipitate was ?ltered, uct. The product obtained by the above-described meth dried and screened, to obtain an isomorphous cocrystal od was analyzed for concentration of the inorganic salt lized product. The product obtained by the above-de and found to contain about two percent by weight of scribed method was analyzed for concentration of the 60 thallium perchlorate. inorganic salt chemically. The results are as follows: EXAMPLE VI NH4ClO4-KMnO4—1.92 percent by weight 'KMnO4 tound. Cocrystallized ammonium nitrate and EXAMPLE II potassium iodate Cocrystallized ammonium perchlorate and 65 About 500 grams of ammonium nitrate are dissolved calcium chromate in about 5 liters of water. The solution is poured into a ?ask provided with a stirrer, thermometer and a drop A 490 ‘gram sample of ammonium perchlorate was dis ping funnel. A solution of about 10 grams of potassium solved in about 3 liters of water. The solution was poured iodate in 500 ml. of water is then slowly added to the into a 3-neck ?ask provided with a stirrer, thermometer 70 aqueous ammonium nitrate solution. The vigorously and a dropping funnel. A solution of 10 grams of cal stirred mixture is then concentrated at about 40 to 50° cium chromate in 500‘ ml. of water was then slowly C. under reduced pressure. When a thick slurry is ob added to the aqueous ammonium perchlorate solution. tained, the precipitate is ?ltered, dried and screened, to The vigorously stirred mixture was then concentrated obtain an isomorphous cocrystallized product. The prod at 50° C. under reduced pressure. When a thick slurry 75 uct obtained by the above-described method is analyzed 3,269,879 5 6 for concentration of the inorganic salt, and found to con Referring to Table III, it can be seen that-the cocrystal tain about two percent by weight of potassium iodate. lized material of Run 1 decomposed far more readily The product is found to be substantially more impact than the mechanical mixture of Run 2. Comparison of sensitive than pure ammonium nitrate. Runs 3 through 6 with Runs 7 through 10 shows that EXAMPLE VII the cocrystallized material is also quicker to decompose than is pure ammonium perchlorate. Run 11 demon Cocrystallized ammonium nitrate and silver nitrate strates that a cocrystallized material containing potassium A 500 gram sample of ammonium nitrate is dissolved permanganate will decompose almost completely when in about 4 liters of water. The solution is poured into heated for 20 minutes at 176° C. In contrast thereto, a ?ask provided with a stirrer, thermometer and a the mechanical mixture of Run 12 underwent only an dropping funnel. A solution of about 10 grams of silver 8.0 percent decomposition after prolonged heating (60 nitrate in about 1000 ml. of water is then slowly added minutes) at 208° C. ' to the aqueous ammonium nitrate solution. .The vigor The illustrative examples and data set forth above ously stirred mixture is then concentrated at about 60° C. clearly show that the novel cocrystallized compositions under reduced pressure. When a thick slurry is obtained, of our invention possess greater impact sensitivity and the precipitate is ?ltered, dried and screened, to obtain will decompose more readily than ordinary ammonium an isomorphous cocrystallized product. The product perchlorate and ammonium nitrate. Thus, the composi obtained by the about-described method is analyzed for tions of our invention will ?nd many uses in the ?eld concentration of the inorganic salt, and found to con of high explosives, as will ‘be apparent to those skilled in tain about two percent by weight of silver nitrate. the art. The elfect of the inorganic su'bstituent salt in the co Having fully described our invention, it is intended crystalline product on the impact sensitivity of am that it be limited only by the lawful scope of the appended monium perchlorate is demonstrated by the data appear claims and a reasonable range of equivalents. ing in the following table. The sensitivity numbers We claim: appearing in the table refer to the drop height of a 2 25 1. A novel composition of matter comprising an kilogram weight at which 50 percent of the trials resulted ammonium perchlorate lattice, and isomorphously sub in an explosion. stituted therein an inorganic salt selected from the group consisting of those having the formula: TABLE II Impact sensitivity MaXb Composition: (centimeters) RDX ______33 wherein M is a cation selected from the group consist NH4ClO4 (pure) ______100 ing of alkali metals, alkaline earth metals and the am NH4ClO4+2% KMnO4 (mechanical mixture) _ 100 monium group, X is an anion selected from the group NH4ClO4-2% KMnOl (cocrystallized) (Com consisting of chromate, iodate, periodate and perman position I from Table I) ______75 ‘ ganate, and a and b are small whole numbers of from NH4ClO4-2% K104 (cocrystallized) (Compo 1 to about 3; and those having the formula: sition D from Table I) ______27 NH4ClO4-2% K103 (cocrystallized) (Compo sition H from Table I) ______50 wherein M’ is a cation selected from the group consist As can be seen from the foregoing table, the isomor~ ing of thallium, silver and copper, X’ is an anion selected phously substituted ammonium perchlorate of the present from the group consisting of perchlorate, chromate, invention possesses ‘a substantially increased impact sen~ iodate, periodate and permanganate, and c and d are sitivity when compared to pure ammonium perchlorate, small whole numbers of from 1 to about 3. or to a mechanical mixture of ammonium perchlorate 2. The novel composition of matter comprising an and the inorganic salt. The foregoing data also demon ammonium perchlorate lattice, and isomorphously sub— strate that by the practice of the present invention, it is stituted therein ‘by cocrystallization, potassium perman~ possible to prepare isomorphously substituted ammonium ganate. perchlorate compositions possessing an impact sensitivity 3. The novel composition of matter comprising an of the same order of magnitude as RDX. ammonium perchlorate lattice, and isomorphously sub The rate of decomposition of pure, mechanical mix 50 stituted therein by cocrystallization, calcium chromate. tures, and isomorphously substituted ammonium per 4. The novel composition of matter comprising an chlorate was investigated using a thermogravimetric ammonium perchlorate lattice, and isomorphously sub; balance. All experiments were carried out at atmos stituted therein by cocrystallization, potassium iodate. pheric pressure, and all of the samples used were of 325 5. The novel composition of matter comprising an Tyler mesh. The sensitivity of the method is such that 55 ammonium perchlorate lattice, and isomorphously sub a weight loss as loW as 0.5 weight percent of the sample stituted therein by cocrystallization, potassium periodate. can be measured. 6. The novel composition of matter comprising an ammonium perchlorate lattice, and isomorphously sub TAB LE III stituted therein by cocrystallization, thallium perchlorate. 60 7. The novel composition of matter comprising an ‘ ' Heating Heating Weight No. Composition Temp, Time, ammonium nitrate lattice, and isomorphously substituted ‘’ 0. Min. percent therein by cocrystallization, silver nitrate. 8. The novel composition of matter comprising an NH4ClO4-2% CaCrOw ______ammonium nitrate lattice, ‘and isomorphously substituted NH4ClO4+2% CaCrO4h_____ 65 therein by cocrystallization, thallium nitrate. 9. The novel composition of matter comprising an ammonium nitrate lattice, and isomorphously substituted therein by cocrystallization, potassium permanganate. 10. The novel composition of matter comprising an 70 ammonium nitrate lattice, and isomorphously substituted therein by cocrystallization, potassium chlorate. 11. The novel composition of matter comprising an B Cocrystallized. ammonium nitrate lattice, and isomorphously substituted b Mechanical mixture. therein ‘by cocrystallization, potassium bromate. 0 Pure. 75 12. The novel composition of matter comprising an 3,269,879 7 ammonium nitrate lattice, and isomorphously substituted permanganate, and a and b are small Whole numbers therein by cocrystallization, potassium iodate. of from 1 to about 3; and those having the formula: 13. The method of preparing a novel composition of matter which comprises dissolving ammonium perchlo MIcXId rate in a solvent; adding to the solvent an inorganic salt selected from the group consisting of ‘those having the wherein M’ is a cation selected from the group con formula: sisting of thallium, silver and copper, X’ is an anion MuXb selected from the group consisting of perchlorate, chromate, iodate, periodate and permanganate, and wherein M is a cation selected from the group consisting c and d are small Whole numbers of from 1 to of alkali metals, alkaline earth metals and the ammonium 10 about 3, said inorganic salt serving as the sole sen group, X is an anion selected from the group consisting sitizing material for the ammonium perchlorate and of chromate, iodate, periodate and permanganate, and being present in an amount within the range of a and b are small whole numbers of from 1 to about about 0.1 to about 10% of the combined weight 3; and those having the formula: 15 of the ammonium perchlorate and said inorganic M’cX'd salt; and (b) effecting an explosion of the explosive charge. wherein M’ is a cation selected from the group consisting 15. A composition of matter in accordance with claim of thallium, silver and copper, X’ is an anion selected 1 wherein the inorganic salt is provided in an amount from the group consisting of perchlorate, chromate, within the range of about 0.1 to about 10% of the com iodate, periodate and permanganate, and c and d are 20 bined weight of the ammonium perchlorate and said small whole numbers of from 1 to about 3; removing inorganic salt. at least some of the solvent until cocrystallization occurs; 16. A composition of matter in accordance with claim and then recovering the isomorphous cocrystallized 15 wherein said inorganic salt is provided as the sole product. sensitizing material for the ammonium perchlorate. 14. A novel explosive process comprising: 25 (a) providing an explosive charge comprising an References Cited by the Examiner ammonium perchlorate lattice, and isomorphously substituted therein an inorganic salt selected from UNITED STATES PATENTS the group consisting of those having the formula: 2,589,532 3/1952 Byers ______149—2 X 30 2,602,026 7/1952 Farr ______149—l7 X MnXb 2,993,767 7/1961 Berl et al. ______149—46 X wherein M is a cation selected from the group con 3,030,179 4/1962 McFarlin et al. ____ 149-46 X sisting of alkali metals, alkaline earth metals and the 3,173,756 3/1965 Griffith ______149-46 X ammonium group, X is an anion selected from the group consisting of chromate, iodate, periodate and BENJAMIN R. PADGETT, Acting Primary Examiner.