Use of fluorographite as a substance which releases energy and relative substance

Abstract

 The use of fluorographite (CF)_n as a substance which releases energy following a chemical transformation and a relative substance, able to release energy, comprising fluorographite is hereto described and laid claim to.

Description

[0001] The invention hereto attached concerns the use of fluorographite as a substance able to release or develop energy as a result of an exothermic phenomenon of chemical or chemical-physical transformation which occurs in an extremely short time.

[0002] It should be specified immediately that hereto fluorographite is taken to mean a chemical compound obtained by means of the fluoridation of graphite, a mineral which is one of the allotropic states of carbon, with elementary flourine, a powerful oxidising agent which in its pure state is a halogen gas of a pale yellow colour.

[0003] The term fluoridation indicates, in addition, the hydrophilising surface treatment with flourine gas performed on a material; in the case in question of the fluoridation of graphite the fluorographite suitable for use as per the present discovery is obtained.

[0004] As is known fluorographite is a substance which is currently used as a solid lubricant in the mechanical and aerospatial industries and in other areas of application, for example to produce the wax applied to the bottom of skis.

[0005] It is known, in addition, that various substances with a high available energy content, in certain conditions, by administering external sources of energy (in the form of heat, light, mechanical energy produced by percussion or by waves of pressure), may give rise to a rapid chemical reaction of the components, followed by the release of an extremely large quantity of energy, mainly thermal, and generally accompanied by gas evolution.

[0006] Such substances are notoriously called explosives and the transformation as above takes the name of explosive reaction.

[0007] Explosives are substances with a high available energy content which, by means of the phenomenon of the explosion, release energy and become stable substances with a decidedly lower energy content.

[0008] Without going into too much detail and remaining in a more general sphere, explosives can be classified according to various criteria.

[0009] According to a first criterion, explosives can be divided into simple or homogenous explosives, if composed of a single chemical substance, and compound or heterogeneous explosives, if composed of several chemical substances.

[0010] Among the simple explosives for example are pentrite, nitro-glycerine, trinitrotoluene (also known by its acronym TNT), picric acid, nitriglicol, while compound explosives include dynamite, gunpowder and ballistite, to mention some of the best known.

[0011] According to a second criterion, explosives are then classifiable into solid, liquid (such as nitro-glycerine) and gaseous explosives.

[0012] Another classification criterion distinguishes between explosives which, upon decomposition, provoke a reaction of complete oxidisation, so-called safe explosives, again such as nitro-glycerine, or incomplete.

[0013] The most important classification of explosives is however in relation to their reactivity under the effect of external energy impulse and to the type of reaction with which they decompose.

[0014] On the basis of such criteria it is possible to identify:

a. slow explosives (or propellants, less correctly powders) which decompose by means of deflagration (first degree explosion) at an explosive speed to the order of several hundred metres per second (m/s) up to 1 Km/s exerting a progressive, gradual decomposition; such explosives are used for example to launch projectiles, rockets and missiles;

b. disruptive explosives (or other explosives, or blast explosives) which decompose by means of violent detonation; such explosives produce effects of breakage and destruction and are used, for example, to charge projectiles or mines or for making hollow charges or explosive cartridges;

c. detonating (or fulminating) explosives: these decompose by means of detonation (second degree explosion) provoked by impact or a primer which propagates at a speed of between 1000 -10000 m/s at explosion temperatures of between 2500-6000°C.

[0015] Deflagrating explosives act relatively slowly therefore while detonating explosives are faster, so that the former are used when a thrust effect is desired rather than a clear shattering of the body to be destroyed, the latter when one wishes the explosive mass to have a violent and demolishing effect.

[0016] The main properties characterising explosives and influencing their application regard thermal stability, sensitivity to external conditions such as impact, friction, triggering and heat, density, hygroscopicity, the power and heat of the explosion, the volume of the explosion gases.

[0017] Achieving suitable values for each of these properties is a need which is strongly felt in the construction of explosive substances which leads to a continual evolution of new materials aimed at improving such properties.

[0018] In particular, the thermal stability, among the most relevant parameters for the purposes of the present invention, must be carefully considered since associated with particularly delicate aspects such as the handling and storage of the explosives.

[0019] It should be remembered in fact, that, by thermal stability of an explosive one means the tendency of the said explosive to resist chemical auto-decomposition.

[0020] The thermal stability of an explosive is not to be confused with its sensitivity to heat, another crucial parameter in the assessment of an explosive, defined as the tendency of the said explosive to explode under the effect of an external thermal or energetic impulse.

[0021] The decomposition of an explosive is accelerated by the increase in temperature, humidity or light which sometimes create risks for people both during handling and storage as well as use of the explosive.

[0022] The thermal stability of an explosive is, in addition, that much greater the more carefully the raw materials composing it are selected, so that it is clear that achieving high figures for such parameter is crucial and not the result of a trivial calculation.

[0023] The invention is also directed at another parameter to be evaluated with extreme care, the work or potential required to produce the explosion.

[0024] Depending on the type of application, it is opportune to increase the value of this parameter, despite generally being modest by virtue of the non-excessive quantity of heat developed in the exothermic explosive transformation.

[0025] However, the work is developed in the course of the extremely brief duration of the explosion and it is for this reason that the effects are destructive.

[0026] The explosive potential of a substance depends on the binding energy between the various elements or chemical compounds mixed in it.

[0027] The bond energy, expressed in Kcal/mole, is the energy required to break a chemical bond or the energy released by the formation of a chemical bond.

[0028] The purpose of the invention is to describe the conditions of use of fluorographite as a component for formulating explosive compounds.

[0029] Specifically, the use of fluorocarbon or fluorographite as components of explosives in the conditions described and in the presence of the co-agents described, is given by way of a non-limiting example.

[0030] Fluorographite used in the conditions and in the presence of the co-agents as described below has surprisingly been found capable of releasing large quantities of energy with a high speed of propagation, such as to render it utilisable as a component of explosives.

[0031] On the contrary, in the absence of co-agents and conditions suitable for triggering the reaction of explosive decomposition, fluorographite shows itself to be thermally stable and behaves in a significantly different way to other explosives characterised by self-propagating decomposition and by the evolution of high pressure under the effect of heat or the transmission of energy by means of impact.

[0032] In fact, fluorographite in its pure state or suspended in an inert organic liquid medium, is used as a solid lubricant, or as a component of grease; it shows itself to be capable of inducing resistance to conditions of severe friction and wear and to protect metal or polymer surfaces from the effect of bodies rolling or sliding over the same.

[0033] lt is also the purpose of this invention to describe the possible use of fluorographite and/or fluorocarbon as a component for making explosives with comparable characteristics to known explosives.

[0034] The aforesaid objectives are achieved by the use of fluorographite (CF)_n as a substance releasing energy following a chemical transformation according to claim 1 attached, which is referred to here.

[0035] Advantageously the invention describes the use of fluorographite as a substance able to develop a large quantity of energy by means of a chemical transformation which occurs rapidly following the triggering of an explosive reaction by means of the presence of suitable reagents able to trigger the explosive reaction.

[0036] On the other hand said fluorographite has greater thermal stability than known conventional explosives.

[0037] According to the findings of the inventor, fluorographite does not show any signs of chemical decomposition up to 290°C, the temperature at which the first alterations in its molecular structure may be observed.

[0038] In explosive substances rather, such value does not exceed 215÷220°C; in any case, furthermore, fluorographite is thermally stable up to 350-500°C.

[0039] The average energy of the bond between fluorine (F) and graphite (C) is approximately 55-57 Kcal/mole and therefore considerably lower than the 110-112 Kcal/mole of organic compounds,, among which those widely used in the composition of explosive substances.

[0040] As illustration of such we may cite that from laboratory experiments using a Parr calorimetric bomb it was seen that just 120 -140 mg of fluorographite (CF)_n (with 0.7≤5F/C≤1.2) mixed with 100 mg of an oxidant agent, such as sodium peroxide (Na₂O₂), and triggered by heating with an electric coil determined an explosive power such that the lid of the Parr bomb was thrown off and hurled against the ceiling while the explosion of the bomb provoked the destruction of the ceramic surface of the counter which it was sitting on.

[0041] The Parr bomb, as is known, is an instrument which enables the quantitative determination of non-metallic elements (halogens, sulphur, phosphorus and others) in organic substances by means of combustion with sodium peroxide and subsequent analysis of the salts (halogenides, sulphates, phosphates and so on) obtained by the oxidative disgregation of the substance analysed.

[0042] Further characteristics and features of the present invention will be evident from the description below, made by way of an indicative and non-limiting example of its preferred embodiments.

[0043] The use of fluorographite(CF)_n as a substance which releases energy following a chemical transformation which occurs in a brief time, more suitably, explosion, is described below

[0044] Fluorographite takes the form of a powder and as described here has been seen to act as a component for explosives.

[0045] Fluorographite has a molecular ratio (F/C) of fluorine (F) inserted as an interlamellar component between the layers of carbon graphite (C), with an F/C value ranging from 0.7-1.2.

[0046] The molecular ratio (F/C), size correlated to the molar fraction, corresponds in this case to the subscript "n" of the symbol CF.

[0047] Preferably and conveniently, the fluorographite is mixed with one or more oxidising substances.

[0048] According to a preferred form of execution, the oxidising substances comprise metal oxides, such as the aforementioned sodium peroxide, while according to others forms of embodiment the oxidising substances may include other metal peroxides.

[0049] For example, the metals belonging to the first group of the periodic table of the elements, the so-called alkaline metals: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs).

[0050] However in other executions, the metals may belong to the second group of the periodic table, the so-called alkaline-earth metals: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), radium (Ra).

[0051] In other cases the oxidising substances include any of the compounds chosen from the group consisting of nitrates, permanganates, dichromates, chlorates and perchlorates, iodates, hypochlorites or other oxidising substances.

[0052] Among the nitrates, purely as an example, one might mention aluminium nitrate, ammonium nitrate, potassium nitrate, lead nitrate and thallium nitrate.

[0053] In addition, fluorographite may be mixed with the substances traditionally used to make explosives, consisting of or containing carbon (C), sulphur (S), hydrogen (H), nitrogen (N) and so on.

[0054] The oxidising co-reagent substances are always present in a quantity exceeding the stoichiometric of carbon graphite.

[0055] The chemical composition of the explosive of the invention is defined by the molecular formula of the fluorographite and by the coefficients of the stoichiometric oxidisation reaction, from which the composition itself of the explosive compound and the percentage of the components used, derives.

[0056] The quantity of fluorographite depends however on the specific application which the explosive is destined for and, therefore, on the power and brisance required and/or which can be developed.

[0057] The brisance, rather, indicates the ability of an explosive to shatter rock and is calculated using the formula


where: f = specific force
d = density (Kg/l)
v = speed of detonation (m/s)

[0058] Below are some examples of explosive compounds using fluorographite according to the invention.

[0059] EXAMPLE N°1

         2CF + Na₂O₂ --> 2CO + 2NaF

where:

• ΔH° = 786 Kcal/Kg
  heat of explosion (T = 20°C, p = cost.)
• ΔT = 3055°C (rise in temperature following the explosion)
• Cp = 7 cal/(mole K) specific heat CO
• Cp = 11 cal/(mole K) specific heat NaF
• Thermal stability (CF)_n up to 500°C
• Thermal stability Na₂O₂: decomposes at 460°C

[0060] EXAMPLE N°2

         2CF + Li₂O₂ --> 2CO + 2LiF

where:

• ΔH° = 926 Kcal/Kg
  heat of explosion (T = 20°C, p = cost.)
• ΔT = 2800°C (rise in temperature following the explosion)
• Cp = 7 cal/(mole K) specific heat CO
• Cp = 10 cal/(mole K) specific heat LiF
• TNTeq = 980 Kcal/Kg

[0061] Remember that TNTeq is a unit of energy commonly used to measure quantities of energy, especially of explosive substances, such that:

[0062] EXAMPLE N°3

         2CF + Na₂O₂ --> 2NaF + CO + C

where:

• ΔH° = 863 Kcal/Kg
  heat of explosion (T = 20°C, p = cost.)
• Thermal stability (CF)_n up to 500°C
• Melting temperature Na₂O = 1230°C

[0063] EXAMPLE N°4

         2CF + Li₂O₂ --> 2LiF + CO + C

where:

• ΔH° = 815,7 Kcal/Kg
  heat of explosion (T = 20°C, p = cost.)
• Thermal stability (CF)_n up to 500°C
• Melting temperature Li₂O = 1200°C

[0064] EXAMPLE N°5

         CF + NaNO₃O --> NaF + CO + NO₂

where:

• ΔH° = 795 Kcal/Kg
  heat of explosion (T = 20°C, p = cost.)
• Thermal stability (CF)_n ≥ 350-500°C
• Melting temperature NaNO₃ = 307°C

[0065] On the basis of the above exposition, it may be seen how the invention achieves the purposes and creates the benefits previously mentioned.

[0066] In the execution phase modifications to the percentages or quantities of fluorographite indicated in the course of this invention may be made, so long as the molar ratio F/C remains within the range of values of 0.7-1.2.

[0067] It is evident, lastly, that numerous variants to the use in question may be made, without falling outside the sphere of the principles of novelty inherent in the inventive idea expressed here, as it is also clear that in the use of the invention, the materials mentioned may be substituted with other technically equivalent materials as required.

Claims

1. Use of fluorographite (CF)_n as a substance which releases energy following a transformation by chemical oxidisation occurring in a short time.

2. Use of fluorographite according to claim 1, wherein said fluorographite is in a powder form.

3. Use of fluorographite according to claims 1 or 2, wherein said fluorographite has a molar ratio (F/C) between fluorine (F) and graphite (C) of a value ranging from 0.7-1.2.

4. Use of fluorographite according to any of the previous claims, wherein said fluorographite is mixed with one or more oxidising substances.

5. Use of fluorographite according to claim 4, wherein said oxidising substances comprise metal oxides.

6. Use of fluorographite according to claim 4, wherein said oxidising substances comprise metal peroxides.

7. Use of fluorographite according to claims 5 or 6, wherein said metals belong to the first group of the periodic table (alkaline metals).

8. Use of fluorographite according to claims 5 or 6, wherein said metals belong to the second group of the periodic table (alkaline-earth metals).

9. Use of fluorographite according to any of the claims from 4 to 8, wherein said oxidising substances include any of the compounds chosen from the group consisting of nitrates, permanganates, dichromates, iodates, chlorates, perchlorates, hypochlorites, bromates or other oxidising substances.

10. Use of fluorographite according to any of the previous claims, wherein said fluorographite is mixed with substances comprising or consisting of carbon, sulphur, hydrogen, nitrogen.

11. Use of fluorographite according to any of the previous claims, wherein said fluorographite is present in a quantity of at least several milligrams.

12. Use of fluorographite according to any of the previous claims, wherein the quantity of the oxidising components is present at least in stoichiometric quantity in relation to the oxidisation reaction of the fluorographite.

13. Substance able to release energy following chemical transformation in a brief time, wherein said subsistence comprises fluorographite.

14. Substance according to claim 13, wherein said fluorographite has a molar ratio (F/C) between fluorine (F) and graphite (C) of a value ranging between 0.7-. 1.2.

15. Substance according to claim 13 or 14, wherein said fluorographite is mixed with one or more oxidising substances comprising metal oxides and/or metal peroxides.

16. Substance according to claim 15, wherein said metals belong to the first group of the periodic table (alkaline metals) and/or to the second group of the periodic table (alkaline-earth metals).

17. Substance according to claims 15 or 16, wherein said oxidising substances include any of the compounds chosen from the group consisting of nitrates, permanganates, dichromates, iodates, chlorates, perchlorates, hypochlorites bromates or other oxidising substances.

18. Substance according to any of the claims from 13 to 17, wherein said fluorographite is mixed with substances comprising or consisting of carbon, sulphur, hydrogen, nitrogen.

19. Substance according to any of the claims from 15 to 18, wherein the quantity of the oxidising components is present at least in stoichiometric quantity in relation to the oxidisation reaction of the fluorographite.