2,698,228 United States Patent Office Patented Dec. 28, 1954 1. 2 (a) Nitroxyalkyl nitramines having the general struc 2,698,228 tural formula: FLASHLESS R2 John F. Kincaid, Jefferson Township, Alegheny County, 5 NOO-R-N-NO2 where R1 is an alkylene group and R2 is a nitroxyalkyl and Russell C. McGill, Baldwin Township, Aliegheny group or an alkyl group; asCounty, represented Pa., assignors by the Secretary to the United of the States Navy of America (b) Polynitrate esters of polymethylolicycloalkanones of the general formula: No Drawing. Application December 30, 1944, 0 Seria No. 570,808 C(CH2ONO2) 5 Claims. (CE. 52-13) C(CH2ONO2); The present invention relates to and more 5 where n is a small whole number; and particularly to new and improved essentially flashless (c) Polynitrate esters of polymethylolicycloalkanols of propellants suitable for large and cannon. the general formula: It has long been recognized that during military and naval operations carried out at night, an essentially flash C (CHONO) less propellant should be used in order to obviate brilliant 20 (CEI), CHONO2 muzzle flash that might reveal the friendly position or momentarily blind command and fire control personnel b(CHONo. in the vicinity of the weapon. Within recent years, British where n is a small whole number. experimenters have made great strides in solving this As illustrative examples of the foregoing types of non problem by incorporating a substantial proportion (about 25 volatile nitric esters, the following specific com 55%) of nitroguanidine in a double base or “Cordite” pounds may be mentioned purely by way of illustra type of powder. The resulting composition (referred to tion; bis(2-nitroxyethyl) nitramine (hereinafter called generally as "Cordite-N') is essentially flashless when "DNA”), tetramethylolicyclopentanone tetranitrate fired in large caliber cannon and has a force approxi (hereinafter called "Fivonite”), tetramethylolicyclopen mately equivalent to that of Pyro powder. 30 tanol pentanitrate (hereinafter called "Fivolite"), tetra Nevertheless, like other double base powders of the methylolicyclohexanone tetranitrate (hereinafter called prior art, Cordite-N, while far superior from the view "Sixonite'), and tetramethylolicyclohexanol pentanitrate point of flash, suffers from the disadvantage that it con (hereinafter called "Sixolite"). tains a volatile high potential plasticizer, namely nitro glycerine. Under conditions of high temperature storage, I. PREPARATION OF THE NON-VOLATILE this volatile component tends to vaporize with the result PLASTCZERS that the ballistic properties of the powder may undergo The preparation of DINA, as described and claimed in a significant change during storage. In addition, under the copending applications of Wright and Chute, Serial the conditions prevailing in air conditioned and ventilated Nos. 570,813, now Patent No. 2,461,582 and 570,814, powder magazines on modern naval vessels, the nitro 40 now Patent No. 2,462,052, and Blomquist and Fiedorek, glycerine in double base powders exhibits a demonstrable Serial No. 570,804, now Patent No. 2,678,946, all filed of tendency to distill, thereby creating a potential hazard even date herewith, may be accomplished by the dehy due to the possible condensation of a highly sensitive ex dration of the bis(nitroxyalkyl)amine nitrate obtained by plosive at various points in the magazine and ventilating nitrolysis of the appropriate dialkanolamine; for example: system. For these reasons, Cordite-N, while far superior HNO3 to Pyro in respect to flash, does not represent the ideal (a) (HOCH2CH2)2NH -) solution to the flash problem. (b) The principal object of the present invention is to pro (NOOCH2CH2)2NEI.HNO3 mulu-3 vide a new and improved essentially flashless gun powder. (chloride Another object is the provision of a gun or cannon catalyst) powder having the desirable flashless characteristics of 50 Cordite-N without the disadvantages associated with a (NOOCH2CH2)2N-NO -- EO double base powder that contains a volatile high explosive Certain homologues of DINA of the type: pier for the component of the pro pellant. (Noort–H)n-No. A further object is to provide a commercially feasible 55 R. R. method of preparing an essentially flashless non-hygro scopic propellant that does not materially alter in ballistic where one R is an alkyl group and the other hydrogen properties when stored at high temperatures. may be prepared in a similar manner from higher homo Other objects and advantages will be apparent as the logues of diethanolamine, as described and claimed in invention is hereinafter more particularly described. 60 Blomquist and Fiedorek application, Ser. No. 570,805, In accordance with the present invention, it has been now Patent No. 2,481,283, also filed of even date here found that the foregoing objects may be accomplished by with. Certain analogues of DINA of the type: substituting certain relatively non-volatile explosive nitric esters for the nitroglycerine heretofore employed as a where R is an alkyl group, obtained in a similar manner nitrocellulose plasticizer in a Cordite-N type of cannon from the appropriate secondary alkanolalkylamine, are powder. More particularly, the improved propellant of described and claimed in another copending application of the present invention consists of a modified double base Blomquist and Fiedorek, Ser. No. 570,804, also filed of type of powder comprising: even date herewith. (1) Nitrocellulose, 70 The plasticizers of the class represented by Fivonite, (2). An essentially non-volatile thermally stable explo Fivolite, Sixonite and Sixclite are prepared as described in E. nitric ester capable of plasticizing the nitrocellulose, the literature (Ger. Pat. 509,118; Br. Pat. 345,859; U. S. a . 1962,065; compare Davis, The Chemistry of Powder and (3) A sufficient proportion of nitroguanidine to render , John Wiley and Sons, 1943, vol. II, page 285). the finished propellant essentially flashless when fired in a large caliber gun or cannon. 75 II. PREPARATION OF THE PROSPELLANT The nitrocellulose plasticizers employed in accordance In preparing the improved propellant of the present in with the present invention may for example consist of vention, any suitable procedure heretofore used for the the essentially non-volatile members of the following illus preparation of double base powders such as Cordite-N trative classes of compounds that are capable of plas may be used, with the exception that one or more of the ticizing nitrocellulose, namely: 80 above identified relatively non-volatile nitrocellulose plas 2,698,228 3 4 ticizers are substituted for the nitroglycerine employed in to the proper length, tied in bundles and dried in an elec the prior art propellants. Thus the powders of the present tric oven for one day at 30° C. and fourteen days at 45 C. invention may be made in conventional "solvent-extru Other experimental compositions have been prepared sion' equipment without material alteration of the proce successfully using pyrocotton and various mixtures of dural steps heretofore employed in the production of guncotton and pyrocotton. Different solvent proportions double base powders containing a substantial proportion (between 50%-50% and 80%-20% -alcohol) of nitroguanidine. have also been found satisfactory. Experiments have The amount of non-volatile plasticizer required for the also been made with shorter mixing cycle and different present propellants will depend in part on the nature of water jacket temperatures. For most preparations a spa the particular plasticizer and other components selected O ghetti process has also been found advantageous to re and in part upon the characteristics desired in the finished move clumps of uncolloided nitrocellulose and poorly powder. In general, however, satisfactory powders may mixed material as well as contributing to the mechanical be made using approximately the following proportions work done on the colloid. of ingredients: Per cent 5 EXAMPLE II-PREPARATION OF PROPELLANT CONTAINING Nitrocellulose ------15 to 35 FIVONITE AS AN NG SUBSTITUTE Non-volatile explosive plasticizer------15 to 35 The following description will serve as an example of Nitroguanidine ------70 to 30 the use of Fivonite as a nitroglycerine substitute. The composition was chosen again so that the finished powder In order more clearly to disclose the nature of the pres 20 would have approximately the same thermochemistry and ent invention, several specific examples will be described flash properties as British Cordite-N. in detail below. It should be clearly understood, however, The composition of a typical propellant made with that the examples are purely illustrative of the fundamen Fivonite was as follows: tal principles involved and are in no sense intended either Per cent to delineate the breadth or scope of the invention or to 25 Nitrocellulose (13.4% N)------23.0 limit or restrict the ambit of the appended claims. Nitroguanidine ------55.0 EXAMPLE. I.-PREPARATION OF A PROPELLANT CONTAINING Fivonite ------19.0 DINA AS AN NG SUBSTITUTE Centralite #1------3.0 As an example of the use of DINA as a nitroglycerine The Fivonite may be prepared in ordinary laboratory substitute in nitroguanidine propellants, there is described 30 equipment by the procedure described in the literature. below a powder having approximately the same thermo The other ingredients were the same lots that were used chemistry and flash properties as British Cordite-N. in Example I. In the preparation of this powder regular commercial The compounding procedure for this sample was also gun-cotton (13.4% N) was used. The nitrocellulose was the same as that used for the DINA composition de dehydrated by the usual commercial process of forcing 35 scribed in Example I. alcohol through a water wet block of nitrocellulose and pressing to a known alcohol content. The nitrocellulose EXAMPLE III.-PREPARATION OF A PROPELLANT CONTAIN was dehydrated to contain less than the quantity of alcohol ING SLXONITE AS AN NG SUBSTITUTE necessary for the proper solvent ratio, and the additional alcohol added to the mixer with the other solvent. 40 The following description will serve as an example of The nitroguanidine was obtained from the Welland the use of Sixonite as a nitroglycerine substitute. The Chemical Works at Niagara Falls, , and was the composition was likewise chosen to have the same thermo conventional grade used in the manufacture of British chemistry and flash properties as British Cordite-N. Cordite-N. The nitroguanidine as received was a dry, The composition of a typical propellant made with finely divided, crystalline powder. 45 Sixonite was as follows: The sample of DNA used was prepared from dieth Per cent anolamine using the procedure described and claimed in Nitrocellulose (13.4% N)------23.0 the copending application of Wright et al., Serial No. Nitroguanidine ------55.0 570,813, now Patent No. 2,461,582, filed of even date Sixonite ------20.0 herewith. The centralite and solvents used were of the Centralite #1------2.0 grade normally employed in manufac The Sixonite may be prepared in ordinary laboratory ture. The Chemical designations of Centralite I (diethyl equipment by the procedure described in the literature. diphenyl urea) and Centralite II (dimethyl diphenyl urea) The other ingredients were the same lots that were used may be found in the handbook, “The Chemistry of Powder in Example I. and Explosives' by Tenney L. Davis, published by John The compounding procedure, amount of solvent, and Wiley and Sons, Inc. (1943), in volume II at page 319. Solvent composition were the same as in Example I. The solvent used was a mixture of 75% acetone and The use of certain non-explosive plasticizers in a 25% alcohol. The mixture was selected because of the Cordite-N type of propellant is described and claimed in solubility characteristics of the solid explosive. the copending application of Holmes and Lawson, Ser. The composition of a typical propellant "made with 60 No. 524,638, filed March 1, 1944, now abandoned. DINA was as follows: Per cent III. PROPERTIES OF THE PROPELLANTS Nitrocellulose (13.4% N)------20.0 The propellants of the present invention, prepared as . Nitroguanidine ------55.0 illustrated in the foregoing examples, are characterized DINA ------19.0 by three particularly outstanding properties, namely (1) Centralite #1------6.0 flashlessness, (2) low volatility, and (3) low hygrosco The weight of solvent used was 20% of the dry weight picity. of the mixture. I. Flashlessness The alcohol-wet nitrocellulose together with the extra alcohol was mixed for five minutes in a counter-rotating 70 Considering firstly the flash characteristics of the pres sigma blade mixer with cold tap water circulating through ent powder, this property is strikingly shown in the tests the jacket. The dry nitroguanidine was added and mixing summarized in Table I. All the propellants employed in continued for another five minutes. At this point in the these tests were used in charges that gave essentially the mixing cycle the acetone solution of DINA was added and same velocities in a 6'/47 worn naval gun (ca. 2725 mixing continued for thirty minutes while water at 45 C. 75 ft./sec.), a large quantity of decoppering agent (lead was circulated through the jacket. Then the ethyl cen foil) being employed with each charge in order to in tralite was added and mixing continued for forty-five crease the probability of flash. The summary in Table I minutes. Finally, with cool water (20 C.) flowing indicates the percent of flash produced by a given test through the jacket, mixing was continued for fifteen min powder when 250 grams of lead foil was used with each utes, making a total mixing time of 100 minutes. 80 charge as a decoppering agent. A similar test was made After mixing, the dough was quite soft and rather using a still larger quantity (450 g./charge) of decopper cheesy in appearance. The dough was blocked at approx ing agent per charge in order to increase the severity of imately 4,600 lbs./in. and then extruded through an the conditions. The flash results obtained in both of 0.276' die at a pressure of approximately 3000 lbs./in. these tests, as determined on the basis of the photographic. using two 50 mesh Screens. The powder was cut green results, are summarized in Table I.

2,698,228 5 6 TABLE I istics in addition to their common class characteristics: that is to say, the DNA powders differ in certain im Flash: Percent of Flash portant respects from the Fivonite powders. Thus, for of Normal Pyro Pow example, the DINA plasticized powder is somewhat der (average) Superior to the Fivonite plasticized powder in respect to Powder drying time and impact strength. For these and other 225 g., Pb 450 g., Pb reasons, the DINA powder may be preferred over the foil Foil Fivonite powder for certain specific applications. Never theless, for other specific applications, the Fivonite powder Percent Percent 10 may prove to be somewhat more satisfactory in other Standard Pyro------100 100 respects. Pyro containing 4.4% K2SO--- - 33 72 Cordite NIPIM1 added K2SO4- 4. 16 It will be evident from the data discussed above that DINA Powder 2.------0. 9 the propeliants of the present invention are character Fivonite Powder 8------...------0 0 ized by a number of highly advantageous properties that 5 render them particularly attractive when compared with Cordite NIP/M had the following composition: nitro- (13.1% some of the best powders of the prior art. N), 18.70%; nitroglycerine, 18.20%; nitroguanidine, 53.80%; centralite-1, It will also be apparent to those skilled in the art 7.4%, cryolite, 0.30%; and K2SO4, 1.50%. 2 DINA powder consisted of 20 parts pyronitrocellulose, 55 parts nitro that many variations may be made in the detailed pro guanidine, 19.5 parts DINA, 1.5 parts centralite-1, 4 parts dibutyl cedure set forth in the foregoing specific examples. Thus phthalate and 1.5 parts K2SO4 (added). 20 the proportions of ingredients or the preparative condi 3 The “Fivonite Powder consisted of 25 parts pyronitrocellulose, 54. tions described in the examples may be changed within parts nitroguanidine, 17.5 parts Fivonite, 1.5 parts centralite-i, 2 parts wide limits. In some cases it may be desirable to in dibutylphthalate and 1.5 parts K2SO4 (added). corporate additional propellant components, or to add 2. Non-volatility additional steps, or to eliminate certain steps described The non-volatility of the powders of the present in in the example. In other cases it may be desirable to vention compared with the relatively high volatility of employ more than one non-volatile explosive plasticizer, Cordite-N was indicated by placing 4' single perforated or to use a mixture of a non-volatile explosive plasticizer grains of several test powders in open dishes, subjecting and a conventional plasticizer. All such modifications them to an elevated temperature and determining their are to be understood as embraced within the scope of the weight-loss as a function of time. An initial rapid loss 30 appended claims. (corresponding to the residual solvent content of the We claim: powder) was disregarded. The comparative data are 1. An essentially flashless, thermally stable propellant given in Table II. suitable for use as a cannon powder, comprising about TABLE II 15% to about 35% nitrocellulose; from about 15% to 35 about 35% of a non-volatile explosive nitric ester capable Percent Percent Percent of plasticizing said nitrocellulose; and from about 70% Explosive Plasticizer in Explosive Wt.iloss Wt. LOSS to about 30% of nitroguanidine, said explosive plasticizer Test Powder Plasticizer per hr. at per day at comprising bis(2-nitroxyethyl) nitramine. in Powder 100° C. 65° C. 2. An essentially flashless, thermally stable propellant 40 suitable for use as a cannon powder, comprising about Nitroglycerine------18.5 0.25 0.57 20.0% nitrocellulose, about 55.0% nitroguanidine, about DINA.------9.0 0.030 0.020 19.0% bisnitroxyethylnitramine and about 6.0% centralite Fivonite------8.0 0.012 0.09 No. 1. 3. An essentially flashless propellant comprising from Further evidence regarding volatility was obtained in 30 to 70 per cent of nitroguanidine and from 15 to 35 surveillance tests carried out at 78° C. After 3 weeks 45 per cent of nitrocellulose plasticized with bis(2-nitroxy storage, a considerable amount of nitroglycerine had con ethyl) nitramine. densed inside a bottle containing Cordite-N. In contrast, 4. An essentially flashless thermally stable propellant a DINA powder, after six months similar storage ex comprising about 70 to 30 percent nitroguanidine, about hibited only a trace of distilled explosive while a Fivonite 15-35 per cent nitrocellulose, and from about 15 to 35 powder showed no trace of distilled explosive whatsoever. 50 per cent of a nitroxyalkyl nitramine having the general 3. Low hygroscopicity structural formula The hygroscopicity of the present powders compared R with that of so-called "non-hygroscopic' (NH) powder 55 NO2-O-R-N-NO2 and "Pyro' powder was determined by storing test where R1 is an alkylene group and R2 is a radical selected samples in atmospheres of controlled humidity and then from the group consisting of alkyl and nitroxyalkyl. periodically weighing the samples until equilibrium was 5. An essentially flashless propellant comprising ap definitely attained. The data are given in Table III. proximately 55 per cent nitroguanidine, 6 per cent cen TABLE III 60 tralite No. 1 and 20 per cent nitrocellulose plasticized E. itroxyalkyl nitramine having the general structural Percenthygroscopic Moisture, Ola at 30°C, Sample i. 65 NO-R-N-NO2 20% RH 70% RH 90% RH. where R1 is an alkylene group and R2 is a radical selected (1) DINA powder------0.03 0.19 0.3. from the group consisting of alkyl and nitroxyalkyl. (2) Fivonite powder- - 0.01 0.6 0.25 (3) “NH' Powder.-- 0.25 0.65 1,05 References Cited in the file of this patent (4) “Pyro' Powder - 0.50 50 2.50 70 UNITED STATES PATENTS It will be seen from the data in Table III that the Number Name Date powders of the present invention are definitely superior 1,454,414 Skilling ------May 8, 1923 to "NH' and "Pyro' powders in respect to hygroscopicity. 1,582,256 Franklin ------Apr. 27, 1926 Indeed, the present powders open the possibility of ship 75 1,754,417 Davis ------Apr. 15, 1930 ping and storing propellants of this type in relatively 1962,065 Friedrich ------June 5, 1934 cheap wooden boxes. FOREIGN PATENTS 4. Other advantageous properties Number Country Date It should be mentioned that the DINA plasticized 80 543,174 Germany ------Feb. 2, 1932 powders and the Fivonite plasticized powders of the 578,300 Germany ------June 12, 1933 present invention possess certain individual character