US2481283A - Preparation of nitratoalkyl nitramines - Google Patents

Description

Patented Sept. 6, 1949 UNITED STATES PATENT OFFICE PREPARATION OF NITRATOALKYL NITRAMIN ES Alfred T. Blomquist and Fred T. Fiedorek, Ithaca, N. Y., assignors to the United States of America as represented by the Secretary of the Navy No Drawing. Application December 30, 1944, Serial No. 570,805

1 Claim. 1

I (Cyclonite) II (Homocyclom'te) NOrNH-CHgCHg-NH-NO: NOz-N(CH:CH:ONO3):

III (Halelte) IV (DINA) It will be noted that one of the compounds in this group (i. e., DINA) contains two nitroxyalkyl groups in addition to a nitramine group. Possibly because of the presence of these nitroxyalkyl groups, DINA differs from the other three nitramines in that it is capable of plasticizing nitrocellulose. Since DlNA is a solid compound of very low volatility, it is therefore of interest as a replacement for the objectionably volatile nitroglycerine heretofore used in propellant powders of the double-base type. However, DINA exhibits a tendency to crystallize in the colloided nitrocellulose matrix and for this and other reasons it is not entirely without its objectionable characteristics for such applications.

One of the objects of the present invention is to provide a new series of nitramines that may be regarded as derivatives of Haleite.

A more particular object is the provision of a new series of nitramines containing one or more nitroxyalkyl groups in addition to an ethylenedinitramine unit.

Another object is to provide a series of compounds containing a plurality of ethylenedinitramine units.

A further object is to provide feasible methods of manufacturing the amines of the character defined above.

Other objects and advantages will be apparent as the invention is hereinafter more particularly described.

The nitramines with which the present invention is primarily concerned may be regarded as mono or disubstituted derivatives of ethylenedinitramine, having the general structural formula:

where R is either an alkyl, or a nitroxyalkyl or a nitraminoalkyl group, and R. is either a nitroxyalkyl or a nitraminoalkyl group.

As typical examples of this class of compoun the following types may be mentioned: N-alkyl- N (nitroxyethyl) ethylenedinitramines (V) N N -dialkyltriethylenetetranitramines (VI) and N-ALKYL-N'- (2-NITROXYETHYL) ETHYLENE- DINITRAmE (V) NO: NO,-

NO; NO:

The lower melting compound appears to have the structure VIII:

The first type of compound (VI) is unafiected by nitric acid, as would be expected from its formula.

The second type of compound (VIII) when treated with nitric acid cleaves to give two types of products: (a) N-(Z-nitroxyethyl) alkylnitramines, described and claimed in our copending application, Serial No. 570,806, filed of even date herewith; and (b) N-alkyl-N'(-2-nitroxyethyl) -ethylenedinitramines (V), thereby proving the formula for the compound of the type (VIII) and at the same'time providing an alternate route for the synthesis of compounds of type V.

N,N-B1s(2-Nrrnoxxsrnx1.) ETHYLENE- nrmrauvrmr: (VII) Another example of the novel series of nitramines in accordance with the present invention is bis(2 nitroxyethyl) ethylenedinitramine (VII) This type of compound may be conveniently prepared from diethanolethylenediamine (IX), according to the procedure indicated by the following equations:

CHg-NH-CgH4OH HNO: cnrNne-wznloNol The foregoing typical examples of the class of nitramines represented by the formula:

will be sufficient to enable those skilled in the art to prepare their higher homologues and analogues, using procedures similar to those briefly mentioned above.

All representative members of the class that contain one or more nitroxyalkyl groups are characterized by the ability to plasticize nitrocellulose and because of their very low volatility, provide a group of essentially non-volatile high-potential plasticizers for nitrocellulose adaptable for use in the manufacture of double-base type of powders.

In order more clearly to disclose the nature of the present invention, several specific examples will hereinafter be described in considerable detail. It is to be clearly understood, however, that this is done solely by way of example and not for the purpose of delineating the scope of the present invention, or of restricting the ambit of the present claim.

EXAMPLE I Preparation of N-methyl-N -(Z-nitrozryethyl)- ethylenedinitramzne (V) and NEW-dimethyltriethylenetetranitramine (VI) (V) R is methyl: R is 2-nitroxyethyl. (VI) R and R are CH2CH2-N(NO2)CH-a.

(A) Reaction of N-methyZ-ethylene dinitram-ine and ethylene dibromide In a 2-1 flask fitted with stirrer, thermometer, and reflux condenser there were placed 82.0 g. (0.5 mole) of N-methylethylenedinitramine, 560 cc. of alcohol, 500 cc. of water, 28.1 g. (0.5 mole of potassium hydroxide, and 47.0 g. (0.25 mole) of ethylene bromide. The mixture was stirred and refluxed for twenty-four hours. Precipitation of N ,N -dimethyltriethylenetetranitramine began to take place after two hours refluxing.

After completion of the reflux period the mixture was filtered at 70 C., and the crude solid washed with cc. of hot alcohol. The washings were combined with the main filtrate. The yield of crude product from several runs varied from 12.1 g.13.6 g. and melted at 210-213 C. d. (uncorr.) The pure N ,N -dimethyl-triethylenctetranitramine (m. p. 211.5-213 C. d. (uncorr.) was obtained by recrystallizing the crude product from nitromethane.

Analysis: Calcd. for CsHiaNaZ N, 31.64. Found: N, 31.62.

The combined filtrate and washings obtained above werev cooled in the refrigerator overnight and gave a second crop of crystalline material (15.4 g.-l9.5 g.) melting at 83.5-85.5 C. (corn). This low melting impure material was purified by dissolving in the minimum amount of hot acetone, treating with decolorizing charcoal, filtering, and allowing the solution to cool. The crystalline precipitate was separated and recrystallized from aqueous acetone (5 volumes of water to 8 volumes of acetone). There separated on. cooling two solid species, one of which was a small, plate-like, well crystallized solid whereas the other was a light amorphous material. It was possible to separate the two materials mechanically. The mixture in the cold acetone was whirled and the liquid containing. the amorphous material was decanted from the crystalline solid. The process was repeated several times and com-.- plete separation was obtained. The amorphous solid (1.8-2.3 g.) melted at approximately C. This substance was not investigated further.

The low melting crystalline solid (11.2-14.2 g.) melted at 885-90" C. (corn); recrystallization from aqueous acetone did not raise the melting point. The experimental evidenceindicates that this product is isomeric with N ,N -dimethyl-triethylenetetramitramine and probably has the structure: I

crn-r r-on.cnrn cmcm-o-nm-cn.cnA -cn.

NO: l lo: N02

Analysis: Calcd. for CsHraOaNa: N, 31.64. Found; N, 31.58; 31.61.

When the filtrate from the second crop was acidified with 70 per cent nitric acid a. precipitate of impure unreacted N-methyl-ethylenedinitramine separated. From 28-35 g. of unreacted material was recovered.

(B) Structure of high-melting compound formed in alkylatz'on of N-methylethylenedinitramine If the high meltin compound formed in the reaction between N-methylethylenedinitramine and ethylene bromide has the structure:

CHa-IIT-C H1 CHz-N-CH; C HrN-CH; CHzN-C H3 N0, NO: N02 N02 treatment with 98 per cent nitric acid should not affect the compound.

Actually the compound can be recovered unchanged when it is dissolved in 98 per cent nitric acid by quenching with water.

(C) Structure of Low-Melting Compound Formed in Alkylaticn of N-methylethylenedinitramine If the low melting compound formed in the alkylation of N-methylethylenedinitramine with ethylene bromide has the structure:

treatment with 98 per cent nitric acid should cleave the compound to give two products, namely:

Actually two products were isolated when the low melting alkylation product was treated with nitric acid. One of these was shown to be identical with N (2 nitroxyethyl) methylnitramine (MeNENA) and analysis of the other product was in agreement with the formula CsHnOqNs. The experimental details are as follows:

In a 200 cc. flask fitted with stirrer and thermometer there was placed 50 cc. of 98 per cent nitric acid and while the temperature of the liquid was held at C. by means of external cooling, 10 g. of the low melting alkylation product was slowly added. The mixture was stirred for fifteen minutes after addition had been complete and then poured on 150 g. of cracked ice. The crystalline precipitate which formed was filtered, washed with two 50 cc. portions of water, and airdried. The crude solid (Crop I, 6.1 g.) melted at 90-92 C.

The acid filtrate from Crop I was neutralized with sodium bicarbonate. A second crop precipitated and this was filtered, washed with a small amount of water and dried in the air. The crude Crop II (2.3 g.) melted at approximately 35 C. Extraction of this crude material with 150 cc. of ether left a residue of 1.1 g. melting at 85 C.

The alkaline filtrate from Crop H was extracted with three 100-cc. portions of ether and the ether extracts were combined with the ether extract of Crop II. After drying over 30 g. of magnesium sulfate the ether was removed and there was obtained 2.8 g. of N- (2-nitroxyethyl) methylnitramine (MeNENA) melting at 35.5-37 C. (uncorr.). No depression of melting point was observed when it was mixed with an authentic sample melting at 38-40" C.

Crop I and the ether insoluble residue from Crop II were combined and recrystallized from 50 per cent aqueous acetone. The material crystallized as small glistening plates melting at 90.5- 92 C. (corn). Yield, 6.4 g. This material was proved to be difierent from the starting material by taking a mixed melting point.

Analysis: Calcd. for C5H11O-1N5: Found: N, 27.63.

EXAMPLE II Preparation of N,N'-(2-nitroa:yethyl) ethylenedinitramine (VII) (VI) R and R. are 2-nitroxyethyl.

(A) Preparation of N,N'-di-(2-ethanol) ethylenediamine tetranitrate In a 1000 cc. fiask fitted with stirrer and thermometer there was placed 250 cc. of 98 per cent nitric acid. The acid was cooled to 1015 C. by means of external cooling and 49.3 g. (0.35 mole) of N,N'-diethanolethylenediamine was slowly added with stirring. The temperature was maintained at 10-15 C. during this addition. After all of the amine had been added the mixture was warmed to 35 C. and stirred at this temperature for an additional fifteen minutes. The clear solution was poured over 750 g. of cracked ice and the resulting aqueous solution was diluted with 500 cc. of per cent alcohol. The crystalline solid which precipitated was filtered, washed with two 100-cc. portions of alcohol and dried in the air.

The crude product (97.8 g.) melted with decomposition at l57.5 C. (corn) and was purified by crystallization from aqueous alcohol. There was obtained 80.1 g. (75.5 per cent of the theoretical yield) of a white crystalline solid melting with decomposition at 17047? 0. (corn).

(B) Preparation of N,N-bis(2-nitr0a:yethyl) ethylenedinitramine In a 500 cc. flask fitted with a stirrer and thermometer there was placed 18.4 g. (0.05 mole) of N,N'-di(2-ethanol) ethylenediamine tetranitrate, 100 cc. of acetic anhydride, and 1 cc. of concentrated hydrochloric acid. The mixture was heated by a water bath to 50 C. and 1 g. of anhydrous zinc chloride was added to the slurry. An exothermic reaction took place within a minute and it was necessary to apply external cooling in order to maintain a reaction temperature of 50 C. (No reaction occurred when the tetranitrate was heated for fifteen minutes with acetic anhydride or with acetic anhydride and a small amount of hydrochloric acid.) After stirring at 50 C. for half an hour the mixture was poured slowly into 500 cc. of water. In a short while an oil separated which solidified upon cooling. The crude solid was filtered, washed with water, and dried in the air. The impure product (13.7 g.) melted at 58.5-60.5 0. (corn).

The product was purified by precipitating an acetone solution of the crude material with cold water. The product obtained in this way (13. g.) melted at 60-62 0. (corn) Yield, 80 per cent.

Analysis: Calcd; for Found: N. 25.62, 25150".

It will be apparent to those skilled in the art that many variations, modifications and extensions of the foregoing. specific examples may be made without departing from" the spirit and scope of the present invention. All such variations, modifications and extensions are to be understood as included within the ambit of the appended claim.

' A process which comprises treating a compound selected from the group'- consisting of N-=a ll yl-N and- (2-alkanol)ethylenediamme and N,N'-bis(2-alkanol)ethylenediamine; withabout an equivalent amount of nitric acid and about an equivalent amount of a dehydrating fatty acid anhydride in the presence oi a halide-ion-forming catalyst, and then separating the nitroxyalkylnitramine from the resulting reaction mixture.

T. BLOMQUIST.

FRED T. FIEDOREK.

CeHmOmNBi- N, 25.61.

REFERENCES The following references are of record in the file of this 5 UNITED STATES PATENTS Number Nam Date 2,125,221 Cox July 26, 1938 10 OTHER REFERENCES