US3562333A - Fluoro-alkyl-substituted polynitro aromatic amines and nitramines - Google Patents

Abstract

1. THE COMPOUNDS HAVING THE FORMULA:

1-(R1-N(-R2)-),2,4,6-TRI(O2N-),3-R4,5-R3-BENZENE

WHERE R1 IS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN AND A NITRO RADICAL; AND R2, R3 AND R4 ARE EACH SELECTED FROM THE GROUP CONSISTING OF HYDROGEN, A MONOVALENT LOWER ALKYL RADICAL, AND A FLUORO-SUBSTITUTED MONOVALENT LOWER ALKYL RADICAL PROVIDED THAT AT LEAST ONE OF THE SUBSTITUENTS R2, R3 AND R4 IS FLUORO-SUBSTITUTED MONOVALENT LOWER ALKYL RADICAL.

Description

United States Patent Office Patented Feb. 9, 1971 3,562,333 FLUORO-ALKYL-SUBSTITUTED POLYNITRO AROMATIC AMINES AND NITRAMINES Josef .l. Schmidt-Collerus, Denver, (1010., and Don N. Gray, Towson, Md., assignors to the United States of America as represented by the Secretary of the Air Force N Drawing. Filed Jan. 28, 1964, Ser. No. 340,837

Int. Cl. C07c 87/60 U.S. Cl. 260-577 6 Claims This invention relates to fluoro-alkyl-substituted polynitro aromatic amines and nitramines. More specifically, this invention concerns itself with fiuoro-substituted alkyl group derivatives of picramide (I) and tetryl (II) as represented by the following structural formulas:

IIQH2 OzNN CH I l 0 2 (I) N 0 2 (II) in which fluorine is substituted in the N-alkyl group or on the benzene nucleus of the aromatic ring. The preferred compounds of this invention are the trifluoromethyl substituted derivatives of picramide and tetryl.

Picramide, tetryl, ethyl tetryl and butyl tetryl are wellknown for their use in military munitions as primary explosives, boosters, and detonators. These explosives exhibit a much higher explosive potential than TNT or picric acid; but are distinctly more sensitive to shock and heat. Consequently, their military utility is minimized because of the severe conditions encountered by the military during field operations. With this invention, however, it has been found that the undesirable sensitivity characteristics of the above referred to explosives can be abrogated by providing a new class of fiuoro-alkyl-substituted derivatives of picramide and tetryl. These new compounds, although exhibiting a high explosive potential are dis tinctly more resistant to shock and heat. As a result, they are much more useful when employed by the military as primary explosives, detonators, boosters and in other explosive applications. Additionally, the compounds of this invention are useful as dyestuffs in the coloration of cellulosic textile materials and as intermediates in the production of other novel and useful compounds.

Accordingly, the primary object of this invention is to provide a new class of explosives Which are characterized by a high explosive potential coupled with a high degree of thermal and shock resistivity.

Another object of this invention is to provide a new class of fiuoro-substituted alkyl group derivatives of picramide and tetryl.

A further object of this invention is the preparation of novel dyestuffs and dyed textile materials.

The new compounds of this invention have the following structural formula:

wherein R may be hydrogen or a nitro radical and R R and R may each represent hydrogen, a monovalent lower alkyl radical having from 1 to 5 carbon atoms, or a fluoro-substituted monovalent lower alkyl radical having from 1 to 5 carbon atoms provided that at least one of the substituents R R and R is a fiuoro-alkyl group.

Illustrative of the lower alkyl and fiuoro-substituted lower alkyl radicals represented by R R and R are the following: -CF CH CF CH CHF CH2CH2CH2CHF3, 'CH3, C2H5, -C3H8, 01' Othfir monovalent lower alkyl and fluorine-containing lower alkyl radicals either straight chained or branched in structure.

The compounds of this invention represent a new class of explosives; namely, N-fluoro-alkyl and fluoro-alkylsubstituted picramides and nitramines. Typical compounds of the invention are conveniently prepared by nitrating an appropriate substituted trinitroaniline. This starting compound is in turn prepared by effecting a reaction between an equimolar mixture of a fiuoro-substituted trinitrobenzene, such as picryl fluoride; or a chlorosubstituted trinitrobenzotrifluoride, with ammonia or an appropriate substituted amine. The synthesis schemes disclosed by the following examples produce specific compounds but is also representative of the method for synthesizing the whole generic group by the judicious choice of appropriately substituted starting materials.

The following examples illustrate the new compounds of this invention and the basic synthesis scheme by which they are prepared. These examples, however, are by way of illustration only and are not to be considered as limiting the scope of the invention in any way.

EXAMPLE 1 To a solution of 52.5 g. (0.17 mole) of 3-chloro-2,4,6- trinitrobenzotrifluoride in 250 ml. of benzene in a 1-liter separatory funnel was added a solution of 50 ml. of 40% monomethylamine in 150 ml. of distilled water. This mixture was shaken and kept cool by holding the funnel under the water tap. After ten minutes shaking, the solution was dark red. At this point a solution of 20 g. of sodium carbonate in 200 ml. of water was added and again the mixture shaken. The benzene layer was removed, and evaporated on a steam bath, leaving a bright-yellow solid residue. Recrystallization from ethanol gave an 82% yield of 3 trifiuoromethyl-2,4,6-trinitro-N-methylaniline; M.P. 137-138 C.

EXAMPLE 2 Five grams of 3-chloro-2,4,6-trinitrobenzotrifiuoride was dissolved in 30 ml. of dry methyl alcohol and the solution cooled in an ice bath. Gaseous ammonia was then bubbled through the solution until a permanent red color was present. The solution was then filtered through a hard filter and the alcohol solution was concentrated to onethird its volume under reduced pressure to give a dark red precipitate. This was filtered and the filter cake washed with a benzene-n-hexane (50:50) solution. This gave 3- trifluoromethyl picramide which decomposed at 195 C. and changed from the red to the yellow isomorphic form.

EXAMPLE 3 The nitration of 3 trifluoromethyl-2,4,6-trinitro-N- methylaniline from Example 1 was accomplished :by dissolving 12.5 g. (0.04 mole) of the amine in ml. of concentrated sulfuric acid, cooling externally with an ice bath, then slowly adding 15 ml. of concentrated nitric acid with stirring. After the reaction solution had been allowed to stand for several hours at room temperature it waspoured over about 500 g. of shaved ice and the precipitated white solid was collected on a filter and air dried. Recrystallized from 95% ethanol yielded 12 g. (84.5% yield) of 3-trifluoromethyl-2,4,6-trinitrophenylmethylnitramine as a white solid.

EXAMPLE 4 To a solution of 49.4 g. (0.2 mole) picryl fluoride in 400 ml. of 95% ethanol was added 33.5 g. (0.25 mole) of trifluoroethylamine hydrochloride. This suspension was heated to dissolve the solids, then cooled externally with an ice bath. At this point, 50 g. (0.5 mole) of solid sodium carbonate was added slowly with moderate stirring. Evidence of the reaction was noted by a slight temperature rise, evolution of CO and the presence of the characteristic amine odor. The deep-orange solution was then heated on the steam bath for about one hour, poured onto ice and acidified with 3 N hydrochloric acid to congo red. The light-yellow solid was collected on a filter, washed with cold water and air-dried. Recrystallized from 95% ethanol yielded 38.8 g. (62.5% yield) of N-beta,beta,betatrifluoroethyl 2,4,6 trinitroaniline as a yellow solid; M.P.=6770 C. Further recrystallization from 95% ethanol yielded 28.7 g. of pale-yellow crystals; M.P.= 73.574.0 C.

Analysis.-Calculated for C H N O F (percent): C, 30.98; H, 1.62; N, 18.06; F, 18.4. The actual values found were (percent): C, 31.24; H, 1.74; N, 18.21; F, 18.3.

EXAMPLE 5 The nitration of N-beta,beta,beta-trifluoroethyl-2,4,6- trinitroaniline of Example 4 was accomplished by dissolving 12.5 g. (0.035 mole) of the amine in 250 ml. of concentrated sulfuric acid, cooling externally with an ice bath, then slowly adding 14 ml. of concentrated (90%) nitric acid with stirring, keeping the temperature below C. during the addition. After the reaction solution had been allowed to stand for several hours at room temperature, it was poured over about 1 kg. of shaved ice. The precipitated white solid was collected on a filter and air-dried. Recrystallized from 95% ethanol yielded 12.1 g. (98% yield) of 2,4,6-trinitrophenyl-beta,beta,beta-trifluoroethylnitramine as a white solid; M.P. 116118 C.

Analysis.Calculated for C H N O F (percent): C, 27.05; H, 1.14; N, 19.72; F, 16.1. Molecular weight (Rast Camphor), 301.18. The actual values found were (percent): C, 27.46; H, 1.29; N, 19.92; F, 16.3. Molecular weight, 295.

Tetryl, when dissolved in sulfuric acid, is connected to methyl picramide (2,4,6-trinitro-monomethyl-aniline) and nitric acid. This fact is utilized to determine the presence of the nitramine linkage (NNO in organic materials. The nitric acid produced in the reaction oxidizes diphenylamine (colorless) to a quinoidimonium sulfate of N,N'-diphenylbenzidene (blue). It was found that both tetryl and ethyl tetryl (2,4,6-trinitrophenylethylnitramine) react at once at room temperature; however, trifluoroethyl tetryl gives a color reaction slowly at steam bath temperatures. This decreased lability of the N-nitro linkage is attributed to the inductive effect of the fluorine substitution on the ethyl group.

The following two tables disclose the thermal and impact sensitivity of prior known explosives and compares them with the compounds of this invention. The information set forth in Table I may be found in the Encyclopedia of Chemical Technology, edited by R. E. Kirk and D. F. Othmer, vol. 6, pp. 54 and 1551, 'Interscience Encyclopedia, Inc. New York, N.Y. The impact sensitivity data of Table II was ascertained by the Naval Ordinance Laboratory and may be found in Navord Report 5335, Impact Sensitivities, (Oct. 18, 1956), by W. P. Besser and P. G. Rivette.

TABLE I Thermal sensitivity Explosive: Explosion temperature, C. Tetryl 257 RDX 260 PETN 225 Nitroglycerin 222 Picric acid 322 It has been found that the explosion temperature of 2,4,6 trinitrophenyl beta,beta,beta trifiuoroethylnitramine, the reaction product from Example 5, is between 340 C. and 360 C. and, hence, is more stable to heat than those prior known explosives set forth in Table I.

The explosion temperature of ethyl tetry-l is between 260 5 C. and 280 C. The explosion temperature of Table I is defined as that temperature in degrees centigrade required to cause an explosion in 5 seconds.

TABLE II Impact sensitivity Explosive: Impact height, cm. Tetryl 2742 RDX 25 PETN 12-1 3 15 Nitro glycerin 4-6 Picric acid 73-93 TNT l 5 8-l7 1 Ethyl tetryl 1 81 TP ethyl tetryl 2 1 5 6 1 2,4,G-trinitrophenyletllylnitramine.

2 2,4,S-trinitrophenyl-beta,beta,beta-trifiuoroethylnitramine.

From an examination of the information presented in Table II, it can be seen that 2,4,6-trinitrophenyl-beta,beta, beta-trifluoroethylnitramine, the reaction product from Example 5, is less impact sensitive, with the exception of TNT, than the prior known explosives referred to in Table II. The impact height of Table II is defined as that height in centimeters for 50% fire using an ERL machine with a type 12 tool kilograms weight).

An explosive compound is considered to be stable if less than 2 cc. of gas, corrected to normal temperature and pressure, are evolved per gram per 48 hours at 100 C. Stability tests show that 2,4,6-trinitrophenyl-beta,beta,betatrifiuoroethylnitramine evolves less than 2 cc. of gas at 100 C. for 48 hours and, hence, is placed in satisfactory stability Class I. All military explosives, such as ammonium picrate, PETN, RDX, tetryl and TNT, must meet this criterion. The power of 2,4,6-trinitrophenyl-beta,beta, beta-trifluoroethylnitramine is 125% that of TNT as measured by the trauzl lead block test.

From a consideration of the foregoing, it can be seen that the present invention provides a new class of explosive compounds which are especially useful when employed as explosives in military munitions. These compounds exhibit a high explosive potential together with a minimum susceptibility to shock and heat.

The reaction products of Examples 1, 2 and 4 are representative of a new class of compounds; namely, fluoroalkyl and N-fiuoro-alkyl-substituted picramides. This class of compounds, in addition to being useful as explosives, dyes natural and synthetic fibers yellow and their ammonium salts dye those fibers red. Representative of the N-fiuoro-alkyl and fluoro-alkyl-substituted nitramines are the reaction products of Examples 3 and 5.

Obviously many modifications and variations of this invention may be made without departing from the spirit and scope thereof and only such limitations should be imposed as fall within the scope of the appended claims.

What is claimed is:

1. The compounds having the formula:

R II I-Rz O N- N02 where R is selected from the group consisting of hydrogen and a nitro radical; and R R and R are each selected from the group consisting of hydrogen, a monovalent lower alkyl radical, and a fluoro-substituted monovalent lower alkyl radical provided that at least one of the sub- 6 stituents R2, R3 and R4 is fluoro-substituted monovalent References Cited lower alkyl radical UNITED STATES PATENTS 4'11 11 1-2 4,6-t' '1 -N- 1111 '1' 2 3 n Home me yamme 3,418,372 12/1968 Taylor 149 105X 3. 3-tr ifluorqrn e thyl pi cramide miiefa-tnfluoromethyl 2,4,6 tnmtrophenylmethyl-mtra- 5 LELAND A. SEBASTIAN Primary Examiner 5. N-beta b ta,beta-trifluoroethyl-2,4,6 trinitroanilir e. Us CL X R mig.2,4,6-tr1n1tr0phenyl-beta,beta,beta-tnfluoroethylnltra- 149 105; 26O 578

Claims (1)

1. THE COMPOUNDS HAVING THE FORMULA: