US2355817A - Explosive compositions - Google Patents

Description

Patented Aug. 15, 1944 .EXPLOSIVE COMPOSITIONS Donald G. Morrow, Wilmington, Del, assignor to Hercules Powder Company, Wilmington, -Del., a corporation of Delaware No Drawing. Application December 3, 1940, Serial No. 368,317

10 Claims.

This invention relates to improved high explosive compositions containing nitrogen tetroxide and more particularly to explosives containing nitrogen tetroxide and a nitroparafiin.

Explosive compositions containing liquid nitrogen tetroxide have been known for many years. Early forms of these compositions comprised mixtures of liquid nitrogen tetroxide with petroleum ether, kerosene, gasoline, carbon bisulfide, etc. Subsequently other liquids such as benzol, ether and nitrobenzene were proposed for use with nitrogen tetroxide.

These compositions are, however, subject to the disadvantage that they are difficult to handle. since the presence of high proportions of the low boiling point (21 C.) liquid nitrogen tetroxide, which are required for complete oxidation, give the explosive mixtures a higlnvapor pressure.

There is the further disadvantage that the nitrogen tetroxide reacts slowly with most materials during storage so that it is necessary to mix the ingredients shortly before they are-used.

This invention has as an object the production of improved high explosives containing liquid nitrogen tetroxide.

It is a further object of the invention to produce an explosive of this type which may be more readily handled than heretofore.

A still further object is the production of nitrogen tetroxide explosives which are relatively stable during storage.

Another object of the invention is the production of nitrogen tetroxide explosives having as an active ingredient thereof a nitroparafiin.

A still further object of the invention is the production of nitrogen tetroxide explosives characterized by great strength and high detonation rates.

A further object of the invention is the production' of nitrogen tetroxide explosives which, though readily detonated by commercial blasting caps, are only slightly sensitive to impact.

Other objects will appear hereinatfer.

The objects of my invention are in general accomplished by providing explosive compositions comprising mixtures of liquid nitrogen tetroxide with nitroparafiins. I preferably use nitroparaffins having the least negative oxygen balances such as nitromethane, s-dinitroethane and 1,3- dinitropropane. However, any of the lower nitroparaffins will give excellent explosive compositions.

In carrying out my invention, I mix a liquid nitroparafiln with liquid nitrogen tetroxide to form a solution. This may be done in any suitable mixing equipment but is preferably carried out in equipment which is provided with a cooling coil or jacket. vIc cold water or cold brine provided by a refrigerating unit may be used as the cooling medium to circulate through the cooling coil or jacket. This also helps to dissipate the heat of solution which is suflicient to raise the temperature of the solution about 10 to 15 C.

The explosive mixture so obtained can be packed in tin, plastic or glass containers. I have found that no difiiculty is encountered with cor- The gases coming from theoxidation chamber contain nitric oxide, water vapor, nitrogen and oxygen. By a preliminary cooling, most of the water can be condensed and removed. Meanwhile the nitric oxide is oxidized to N02. By using a suitable refrigerating unit, the N02 can be condensed from the gaseous mixtur in the form of liquid N204. in other well known ways.

For the purposes of the present invention, the presence of small amounts of HNO: and N203 are not objectionable, although it is preferable to maintain the nitrogen tetroxide at a high degree of purity. It is well known; of course, that liquid nitrogen tetroxide consists of an'equilibrium mixture of N02 and-N204, the proportions varying somewhat with the temperature and degree of dilution.

For the purposes of the present invention, I have found the lower nitroparaffins to be effective. Thus, for example, nitromethane, nitroethane, 1- or 2-nitropropane, primary or tertiary nitroisobutane, symmetrical dinitroethane, 1,3-dinitropropane, etc., either alone or admixed together may be used. I prefer, however, to use nitroparaflins with a relatively small negative oxygen balance such as nitromethane whose oxygen balance is 39.3 per cent.

While generally speaking, the maximum strength is developed by explosives which contain just sufilcient oxygen to convert the carbon to carbon dioxide and the hydrogen to water, excellent explosive mixtures can be obtained with positive and negative oxygen balances.

mixtures of nitromethane and nitrogen tetroxide, varying from per cent nitromethane The N204 can also be produced Thus De Lni and 10 per cent nitrogen tetroxide to about 35 per cent nitromethane and 65 per cent nitrogen tetroxide form powerfulexplosives.

Byway of illustration, I have shown in Table 1 five examples of nitromethane and nitrogen tetroxide mixtures with oxygen balances varying from 28.5 per cent to +26 per cent. It will .be observed that their detonation rates range from 6250 to 6700 meters per second. In strength, these explosives are as strong as or stronger than nitroglycerin. All of the mixtures shown in Table 1 exhibit boiling points considerably higher than the Example F, nitrogen tetrox de-kerosene which is shown for comparison. y suitable choice of composition a mixture with a boiling point of about 80 C. can

be obtained and can be handled without difilculty. This mixture has a rather negative oxygen balance which is not disadvantageous, how- I For comparison.

Examples of mixtures containing nitroethane and nitrobutane are shown in Table 2.

Table 2 Examples Nitrocthane, C lEhNO, 42 l-nitrobutane, C4HINO: 30 Nitrogen tetroxide, N104 58 70 Oxygen balance... percent. 0 Density g./cc. 1. 25 1. 27 Sensitivity 1 Shoots with No. 8 cap.

Explosives of the type described will be found extremely useful in quarry blasting and open-pit metal mining where a powerful explosive with tures to be stored without danger of change and/or deterioration and eliminates the necessity of mixing the explosive just prior to its use. Explosive mixtures containing nitroparamns are further characterized by remarkably great o strength and high detonation rates.

An additional advantage in some cases is that explosivemixtures according to the present invention are only slightl sensitive to impact, though they may be readily detonated by commercial blasting caps. A further advantage is thatmixtures containing nitroparaifins such as nitromethane are much easier and pleasanter to handle. Such mixtures contain a large proportion of nitroparafiin. Thus a balanced mixture of nitromethane and liquid nitrogen tetroxide contains 64 per cent nitromethane and 36 per cent nitrogen tetroxide. A similar mixture with kerosene contains 82 per cent nitrogen tetroxide. The iormer has a boiling point of 48 C.- and the latter, 23 'C. It is thus apparentthat the mixture contalningnitromethane is less volatile and hence pleasanter and easier to handle.

a high rate of detonation is needed. These explosives are also useful for various military purposes.

Explosive mixtures according to the present invention are characterized by remarkable resistance to chemical interaction under ordinary conditions of storage whereas mixtures of nitrogen tetroxide with benzene, nitrobenzene, kerosene, etc., tend to react upon storage.

ance to interaction permits the explosive mix- This resist- It will beunderstood that the details and examples hereinbefore set forth are illustrative only and that the invention as broadly described and claimed is in no way limited thereby.

' What I claim and desire to protect by Letters Patent is: 1 a

1. An explosive composition comprising liquid nitrogen tetroxide and nitromethane.

2. An explosive composition comprising liquid nitrogen tetroxide and nitromethane said composition having an oxygen balance between about -25 and about +25%.

3. An explosive composition comprising a mixture of liquid nitrogen tetroxide and nitroethane.

4. Anlexplosive composition comprising liquid nitrogen tetroxide and nitropropane.

5. An explosive composition comprising liquid nitrogen tetroxide and nitroethane, said composition having an oxygen balance between about 25 and about +25%. p

6. An explosive composition comprising liquid nitrogen tetroxide and nitropropane, said composition having an oxygen balance between about -25 and about +25%. g

7. An explosive composition comprising liquid nitrogen tetroxide and a nitroparaffln having less than five'carbon atoms and less than three nitro groups;

8. An explosive composition comprising liquid nitrogen tetroxide and a nitroparaflln having less than five carbon atoms and less than three nitro groups, said composition having an oxygen balance between about .25 and about +25%.

9. An explosive composition comprisingliquid nitrogen tetroxide and an oxygen deficient liquid nitroparafiin having less than fiv carbon atoms.

10. An explosive composition comprising liquid nitrogen tetroxide and an oxygen deficient liquid nitroparaflin having less than fiv carbon atoms, said composition having an oxygen balance between about -25 and about +25%.

DONALD G. MORROW.

CERTIFICATE OF CORRECTION. Patent No. 2,555,817. August 1 19th,,

- DONALD e. MORROW,

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows Page 2, first column, line 28, Table l, fifth column thereof, for the numeral "60" read -5Q-; line 55, same table, last column thereof, for "55" read "25- and that the said Letters Patent should be read with this correction there'- i-n that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 5rd day of October, A. D. 19%.

Leslie Frazer (Seal) Acting Commissioner of Patents.

OERTIFI GATE OF CORRECTION Patent No. 2,555,817. August 15, 19th.

- DONALD G. MoRRow,

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, first column, line 28, Table'l, fifth column thereof, for the numeral "60" read --50-; line 55, same table, last column thereof, for "55" read --25--;

and that the said Letters Patent should be read with this correction there-'- i-n that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 5rd day of October, A. D. 191m.

Leslie Frazer (Seal) V O Acting Commissioner of Patents.