Patented Sept. 8, 1942 2,295,104

UNITED STATES PATENT OFFICE 2,295,104 MANUEFACTURE OF NORMAL LEAD TR NITRORESORCNATE AND DOUBLE SALTS THEREOF Frederick M. Garfield, St. Louis, Mo., assignor to Western Cartridge Company, East Alton, II., a corporation of Delaware No Drawing. Application June 29, 1939, Serial No. 281,818 1. Claims. (C. 260-435) This invention pertains to the manufacture of ing the agitation, a lead acetate solution, pre normal lead trinitroresorcinate and novel double pared by dissolving 1260 g. of normal lead acetate salts thereof. trihydrate (Pb(C2H3O2)23H2O) in 3000 C. c. of The manufacture of normal lead trinitrore Water and filtering, was added to the Suspension SOrcinate (or styphnate) has heretofore been de 5 at a uniform rate over a period of twelve minutes. scribed as involving the interaction of a solution After completing the addition, agitation Was Con of the lead salt of a strong inorganic acid, such tinued at 55° C. for a further period of five as lead nitrate, with a Solution of an alkali or minutes, and the final result was a precipitate alkaline-earth styphnate, in the presence of an consisting of crystalline normal lead trinitrores Organic acid. Prior attempts to obtain a suit O orcinate. After cooling the suspension to about able product more directly, for example with the 25° C., the Supernatant liquid was decanted, and use of free styphnic acid, have been unsuccessful. the crystals were washed by agitation in fresh Thus, it is Stated in U. S. Patent 1,443,328, page Water, this process being repeated several times. l, lines 52-57, "If any soluble lead salt, for in A yield of 1450 grams (93.2% of theoretical) was stance, acetate of lead, is precipitated With tri obtained, the specific gravity of the crystals being nitroresorcine or the Soluble salts of the same, measured as 3.086 at 30° C. and the lead content there Will always be obtained only a mixture of a as 44.4% (theoretical-44.3%). The explosive basic Salt and free trinitroresorcine.' properties of the product were likewise found to Contrary to this statement, I have found that correspond with those of normal lead Styphnate, normal lead trinitroresorcinate Can advan- : tageously be prepared by treating trinitroresorcin the instantaneous flash point, for example, as in Suspension or Solution with a solution of lead measured on a Dennis heated bar melting point acetate or other lead salt of a weak organic acid, apparatus, being 325 C., as compared with 320 when precautions are taken in accordance with 330° C. for various samples of normalled styphnate certain phenomena, which I have discovered. prepared by interaction of sodium styphnate and Furthermore, the reaction may be utilized to pre lead nitrate in the presence of acetic acid. The pare new double salts of normal lead trinitrores crystals were characterized by a high degree of orcinate. uniformity in size throughout the batch, were in accordance with this invention, generally hexagonal in outline, had a length 2-4 times stated, the said normal salt may be obtained by their width, and settled rapidly from suspension treating trinitroresorcin, in solution or suspen 30 to form a paste containing less than 30% water. Sion in a suitable liquid medium, with close to A novel and surprising phenomenon observed the theoretical proportion of a soluble lead Salt during the course of the above procedure, to of a weak organic acid. Preferably, the propor which many of the advantageous features of the tions are such as to provide at least one atom of process may be attributed, is the formation of a lead per molecule of trinitroresorcin, and where 35 clear solution after about one-third to one-half an excess of lead salt is used, it should generally of the lead acetate solution has been added. amount to less than ten to fifteen per cent when That this may consist of a colloidal Solution, poS the normal salt is desired. The use of a larger sibly of a lead acid styphnate, is indicated by the excess of such lead salts has been found to cause fact that when a portion is rapidly cooled to room the formation of novel explosive double salts of 40 temperature, a transparent elastic gel resultS. normal lead trinitroresorcinate, the properties of The intermediate formation of this clear solution which make them suitable for use in various ex is significant in that it enables the attainment plosive compositions. of exceptional uniformity in the Subsequent pre The following examples illustrate the prepara cipitation. A similar condition is realized with tion of normal lead trinitroresorcinate and 45 the use of other soluble lead salts of Weak organic double salts thereof in accordance With this in acids as described in Subsequent examples. Vention. Eacample II Eacample I A procedure identical with that of the first 816 grams of styphnic acid were suspended in 50 example was followed, excepting that a Solution 4500 c. c. of Water in a suitable container by of basic lead acetate, having the composition means of a mechanical agitator. The container Pb(OH)2.Pb(CH3O2)2, was employed, in an was placed in a heating bath and the suspension amount which furnished the same weight of lead was brought to a temperature of about 55 C. as utilized in the previous example. Normal lead While maintaining this temperature and continu- 55 styphnate, having an instantaneous flash point 2 2,295,104 resorcinate. After a digestion period of five min of 320 C., was obtained, the yield amounting to utes after completing the addition, the Sus 95% of the theoretical. pension was cooled to room temperature and Eacample III the crystals were washed with pure water. An A procedure identical with that of Example I 89% yield of normal lead trinitroresorcinate was was followed, excepting that twice the amount obtained, and the product was found on analysis of lead acetate specified therein was added. It to contain 44% lead and to have an instantane was found that the crystals of normal lead styph ous flash point of 330° C. nate. Which Were first formed became converted Eacample VI on further addition of lead acetate solution to lo elongated yellow crystals. . . This product was . . The procedure of the preceding example was found on analysis to contain 52.9% lead, 15.2% repeated, with the use, however, of more than carbon, and 5.3% nitrogen; when treated with twice the amount of lead propionate relative to concentrated sulfuric acid, acetic acid was lib the trinitroresorcin. Normal lead trinitrores erated. The analysis and mode of formation ... " orcinate crystals were precipitated when about indicate that this material is a hitherto unknown one-half the propionate solution had been added, double Salt of normal lead trinitroresorcinate and and conversion of these crystals to elongated lead acetate, which corresponds to the formula, yellow crystals occurred when about three C6H(NO2)3O2Pb (CH3O2)2Pb (theoretical Con fourths of the Solution had been added. The tent 53.4% lead, 15.5% carbon, and 5.4% nitro- ) mixture was digested for an hour at 60° C., the gen). Crystals of this double salt likewise result suspension was then cooled, and the crystals when previously prepared and washed normal were filtered and Washed. . . The lead content of lead trinitroresorcinate Crystals are treated . With , , , the product was found on analysis to be 51.1% lead acetate Solution. The Specific gravity of the 51.5%), and the instantaneous flash point was crystals was found to be 3.1 at 30° C., and the z 310° C. This product is thus a new explosive instantaneous flash point was found to be 315°C. derivative of normal lead trinitroresorcinate, a The material was found capable of being brought crystalline double salt thereof, with lead pro to explosion not only by the application of heat, pionate. It was found to be insoluble in alcohol, but also to a desirable extent: by shock and/or ether, and acetone and somewhat soluble in friction. 30 water. Eacample IV Eacample VII A co-precipitated mixture of normal lead The procedure of Example : V was repeated, tritroresorcinate, and normal lead trinitroresor with the substitution of lead lactate for the cinate-acetate was obtained by the addition in propionate. . . The product consisted of crystal ten minutes of a solution of normal lead acetate line normal lead styphnate having an instanta to a suspension of trinitroresorcin in water neous flash point of 335° C. and found by an at 60°. C., followed by agitation of the reaction alysis to contain 43.9% lead. mixture at that temperature for thirty minutes. When the reaction between trinitroresorcira The amounts were such as to provide 1.5 nois {) and lead acetate or Similar lead Salt is carried of lead per mol of trinitroresorcin. The normal. " Out at 20°-25 C., the first precipitate obtained lead trinitroresorcinate which was first precipi consistS of a gelatinous fibrous material, prob tated was partly converted to crystals of the ably normal lead trinitroresorcinate dihydrate, double salt, so that the final product after Which after a period of about thirty minutes cooling and washing with water consisted of a becomes completely converted into crystals which mixture of the two types of crystals in close - correspond in properties to the form which has to equimolecular proportions. This was con been described in the literature as the monohy firmed by the analysis of the product for its lead drate. As the reaction temperature is raised, the content, which was found to be 48.9% (theoret time required for converting the fibrous precipi ical 49.8%). The instantaneous flash point was tate to crystals of monohydrate becomes shorter, found to be 320° C. 39 SO that When the reaction is carried out at tem The conversion of normal lead styphnate crys peratures above about 60° C., no substantial tals of double salt was found to recuire agitation amounts of this intermediate fibrous precipitate for a length of time dependent oil the amount of are noticeable. lead acetate present, the period being shorter Most favorable results in preparing the nor when the amount was increased. At a tempera nal Salt in a form suitable for use in explosive rture of 55° C., normal lead styphnate crystals compositions appear to be obtainable at reaction appeared to be unchanged when held in contact temperatures between about 40° C. and 70° C., with Solutions containing less than one-tenth Since lower temperatures require a fairly long mol of lead acetate per mol of lead styphnate, i) precipitation period while higher temperatures while double salt crystals formed in 16 minutes may lead to undesirably large crystals. The When the molar ratio of lead styphnate to lead reaction may be carried out at a constant tem acetate was 2:1, and in 11 minutes at a 1:1 perature or at temperatures which are varied ac molar ratio. Cording to Some fixed schedule, as desired. The Eacample V (3.5 Concentrations and the rate as well as order of To a suspension of trinitroresorcin in five addition are likewise subject to controlled varia times its weight of water at 60° C., there was tion by those skilled in the art. It may further added in ten minutes a solution containing Sub more be desirable at times to add a small amount stantially an equimolecular quantity of lead pro of a Substance adapted to control the growth of pionate in three times its weight of water. A 7) the resulting crystals, such as, for example, gum clear Solution was obtained when one-half to arabic. The trinitroresorcin may be the pure three-quarters of the latter solution had been acid, characterized by a light yellow color, or it added, this was then followed by precipitation may consist of the brown-colored acid, contain of 'gel' clusters, which Soon thereafter became ing one or more compounds resulting from the transformed to crystals of normal lead trinitro- 7.5 interaction of resorcin with oxides of nitrogen 2,295,104 3 and subsequent nitration. However, use of the lows, when, for example, normal lead acetate is latter appears generally less desirable due to a uSed: tendency toward the formation of misshapen crystals or of crystal clusters. In carrying out the manufacture of normal 5 lead trinitroresorcinate, the observance of pre cautions appropriate to the highly explosive nature of the product is desirable. The Sim It is to be understood that the specific details plicity of my improved process is beneficial in hereinbefore described are to be taken as illus this respect as facilitating the employment of re 10 trative and not as limiting the scope of the inven mote control. The reaction vessel employed tion, and that variations which may be realized should be one with a Smooth Surface having no by those skilled in the art are included within tendency to promote the formation of a crust of the language of the appended claims. precipitate thereon. I claim: In contrast to the successful results described 1. In the manufacture of a normal lead salt of above, it was observed that no useful product trinitroreSOrcin, the process comprising inter was obtainable when trinitroresorcin was treated acting trinitroresorcin and at least an equimolal with solutions of lead salts of strong acids, such quantity of lead acetate. as lead nitrate, the trinitroresorcin remaining 2. In the manufacture of a normal lead salt of substantially unchanged after treatment. 20 In general, therefore, excellent yields and trinitroreSOrcin, the process comprising interact quality of crystalline normal lead trinitroresor ing trinitroreSOrcin and a solution of a lead salt cinate may be obtained in accordance with this of a lower aliphatic acid in proportions to pro invention by interacting trinitroresorcin directly Wide One to about two mols of lead per mol of with a solution of a lead salt having properties trinitroresorcin. similar to the salts specifically mentioned herein. 3. In the manufacture of a normal lead salt of These are lead salts of weak acids, Such as the trinitroresorcin, the process comprising interact lower aliphatic and substituted aliphatic acids, ing trinitroresorcin and a solution of substantially which are much weaker acids in aqueous solu One to two molecular equivalents thereof of lead tion than trinitroresorcin, the latter being char 30 acetate at a temperature of 40° C. to 70° C. acterized as a strong acid. These Suitable lead 4. In the manufacture of a normal lead salt salts are further characterized by appreciable of trinitroresorcin, the process comprising inter solubility in the liquid reaction medium. A Solu acting trinitroresorcin and a solution of substan bility of the order of several per cent is sufficient, tially one to two molecular equivalents thereof of as indicated by the fact that excellent results lead acetate at a temperature of about 55° C. were obtained in the procedure of this invention 5. In the manufacture of a normal lead salt of With the utilization of lead formate, Which is trinitroresorcin, the process comprising forming soluble in Water only to the extent of 2.8% at a Suspension of trinitroresorcin, heating the Sus 25° C. and 18% at 100° C. pension to 40-70° C., and adding thereto a solu AS indicated above, the proceSS of this inven 40 tion of a lead Salt of a lower aliphatic acid in tion may likewise be utilized in the preparation an amount to provide one to about two mols of of novel double salts of normal lead trinitro lead per mol of trinitroresorcin. resorcinate with lead salts of Weak Organic acids, 6. In the manufacture of a normal lead salt of such as the lower aliphatic acids. These new trinitroresorcin, the process comprising forming derivatives of normal lead trinitroresOrcinate are a suspension of trinitroresorcin, admixing there well qualified because of their properties for use With a Solution of a lead salt of a lower aliphatic in explosive and defiagrating Compositions, Such acid to form a clear solution, and forming a as blasting cap ignition compositions and alm precipitate by adding a further amount of the munition priming mixtures wherein one or more lead Salt solution. of them may be combined with well known initi 7. In the manufacture of a normal lead salt ating explosives such as mercury fulminate, lead of trinitroresorcin, the process comprising form azide, lead picrate, and diazodinitrophenol, With ing a clear Solution by the admixture of trinitro oxidizing agents such as metallic nitrates, di resorcin and a lead acetate solution at a tem oxides, chromates and permanganates, and/or perature between 40° C. and 70° C., and forming fuels such as sulphides, thiocyanates, and sili- 5 5 a precipitate by adding to said solution a further cides. amount of lead acetate Solution. 8. As a new product, a crystalline double salt By this invention there is thus provided a new Of normal lead trinitroresorcinate and lead and improved process for the manufacture of acetate. normal lead trinitroresorcinate, which proceSS is 9. As a new product, a crystalline double salt characterized by ease and economy of operation, 0. of normal lead trinitroresorcinate and lead simplicity of control, high yield and uniformity propionate. of product, as well as the advantageous feature 10. As a new product, a crystalline double salt of providing a relatively large amount of product of normal lead trinitroresorcinate and a soluble for a given volume of reaction liquid. Further lead Salt of a lower aliphatic acid. more, the process is capable of yielding novel 11. In the manufacture of a normal lead salt explosive derivatives of normal lead trinitro of trinitroresorcin, the process comprising inter resorcinate. acting trinitroresorcin and at least an equimolal The chemical reactions which occur in the quantity of a soluble lead salt of a lower aliphatic preparation of normal lead trinitroresorcinate and acid. a double salt, respectively, may be Written as fol 70 FREDERICK M. GARFIELD.