DE19712820A1 - Burning moderators for gas-generating mixtures - Google Patents

Abstract

The invention relates to multi-metal oxides of general formula (I) Mo12-a-b-c Va M<1>b M<2>c Ox, wherein the variables have the following meaning: M<1> = W and/or Nb, M<2> = Ti, Zr, Hf, Ta, Cr, Mn, Re, Ag, Cu, Si, and/or Ge, a = 0.1-6, b = 0-6, c = 0-6, with the proviso that a + b + c = 0.1-6 and x = a number determined by the valence and abundance of elements in (I) different from oxygen. Said oxides are used as combustion moderators for gas-producing mixtures. They can be used, particularly in air bag systems, as a mixture or two-phased multi-metal oxide mass with multi-metal oxides containing copper.

Description

The invention relates to the use of multimetal oxides as a combustion modera gates for gas-generating mixtures, as well as these mixtures and their ver turn.

Gas-generating mixtures or gas generator propellants develop at Ver burning a large amount of gas, its use in, for example, rocket engines driven or airbag propellants. This usually becomes a fixed one Used fuel, the combustion behavior by suitable additives for the respective use is adapted. With appropriate additives, the Burning speed and the pressure curve during burning are controlled.

A known solid fuel for rocket engines and gas generators is based on Ammonium nitrate in pure or phase-stabilized form. In EP-A1-0 705 809 is such a solid fuel for rocket engines and gas generators wrote that from 35 to 80 mass% ammonium nitrate in pure or with Nickel oxide, potassium or cesium nitrate phase-stabilized form with a average grain size of 5 to 200 µm, 15 to 50% by mass of a binder systems from a binder polymer and a high-energy plasticizer, as well 0.2 to 5 mass% of a combustion moderator made of vanadium / molybdenum oxide as Oxide mixture or mixed oxide.  

Other propellants are based on nitrogen-rich and low-carbon fuels, such as nitroguanidine (NIGU), triaminoguanidine nitrate (TAGN), diguanidium 5,5'-azotetrazolate (GZT) or 3-nitro-1,2,3-triazol-5-one ( NTO). Such a gas-generating mixture is described in DE-C1-44 42 169, where V ₂ O ₅ / MoO ₃ mixed oxides and / or oxide mixtures are used in addition to the fuel as an oxidizer, copper diamine dinitrate and as a catalyst or combustion moderator.

The burning behavior of these gas-generating mixtures is not with all types satisfactory.

The object of the present invention is to provide new burn-up moons derators for gas-generating mixtures, particularly in airbag systems and rocket engines lead to improved combustion behavior.

The object is achieved by using multimetal oxides of the general formula I

Mo _12-abc V _a M ¹ _b M ² _c O _x (I)

in which the variables have the following meaning:

M ¹ = W and / or Nb,
M ² = Ti, Zr, Hf, Ta, Cr, Mn, Re, Ag, Cu, Si and / or Ge,
a = 0.1 to 6, preferably 0.5 to 4.5,
b = 0 to 6, preferably 0.1 to 6 and particularly preferably 0.5 to 4,
c = 0 to 6, often 0.1 to 6 or 0.5 to 4,
with the proviso that a + b + c = 0.1 to 6, preferably 0.5 to 4.5 and
x = a number which is determined by the valency and frequency of the elements in I other than oxygen,
which are characterized in that
their atomic spatial arrangement using Cu-Kα radiation (λ = 1.54178 Å) results in a powder X-ray diffraction spectrum (the intensity A of the diffracted X-ray radiation plotted as a function of twice the diffraction angle (2θ)), which in the 2θ range (given in the unit for plane angles: ° = degrees) from 5 ° to 50 ° contains at least the following characteristic diffraction lines A ³ , A ⁵ , A ⁹ and A ¹⁰ , but preferably at most the following diffraction lines A ¹ to A ¹⁰ :

as combustion moderators for gas-generating mixtures.

The wavelength λ of the X-ray radiation used for diffraction and the diffraction angle θ are linked via the Bragg relationship:

2 sin θ = λ / d,

where d is the network plane distance of the atoma belonging to the respective diffraction line ren room arrangement is.

Favorable multimetal oxides I include those with x = 15 to 50. Preferably, x is 25 to 40 and particularly preferably 30 to 40. Furthermore, among the multimetal oxides I, those with c = 0 are suitable. In the case c = 0 and M ¹ = exclusively W are preferably multimetal oxides I in which vanadium is ≧ 25, or ≧ 50, or ≧ 75, or ≧ 95, or 99% as V ⁴⁺ .

It is typical of the multimetal oxides I used according to the invention that their powder X-ray diffraction spectrum using the CU-Kα radiation in the 2θ range from 5 ° to 50 ° as the characteristic fingerprint has at least the diffraction lines A ³ , A ⁵ , A ⁹ and A ¹⁰ , but preferably contains at most the diffraction lines A ¹ , A ² , A ³ , A ⁴ , A ⁵ , A ⁶ , A ⁷ , A ⁸ , A ⁹ and A ¹⁰ , in particular all diffraction lines A ¹ to A ¹⁰ .

Remarkably, part of the diffraction lines are those that have a relatively large half-width FWHM (the width of the diffraction line (the intensity plotted as a function of 2θ) at half the height of its maximum amplitude, given in the unit for plane angles), what an extraordinary expression of short-range and long-range order in the new ones Multimetal oxides I reflects (see examples). This special design of short-range and long-range order according to this view a. for the special combustion-moderating properties of those used according to the invention Multimetal oxides I responsible.

As a result of the special half-width ratios, the powder X-ray diffraction spectrum of the multimetal oxides I used according to the invention does not contain the diffraction lines A ⁱ in a completely resolved form. However, the presence of the majority of the diffraction lines A ⁱ (after deduction of the linear background) is visually immediately recognizable as a relative maximum in the outline of the powder X-ray diffraction spectrum of the multimetal oxides I, the location of these relative maxima in this document indicating the location of the Diffraction lines A ⁱ defined.

After subtracting the linear background (the connecting line between A (2θ = 5 °) and A (2θ = 65 °)), these diffraction lines A ¹ to A ¹⁰ can also be referred to as follows, with the highest intensity of the diffraction lines A ¹ to A ¹⁰ assign them to relative line intensities (I _A rel = (I / I _o ) × 100%), using the amplitude measured from the baseline to the relative maximum as the intensity measure:

Multimetal oxides with these relative line intensities are preferred puts.

With regard to this specification of the line intensities I _A rel, it should be noted that the relative line intensities, in contrast to the position of the lines, are noticeably influenced in a manner known per se to the person skilled in the art, in contrast to the position of the lines, by means of which individual crystal orientations which result in the case of various powder intake preparations based on the anisotropy of the crystal form and therefore have a lower significance for the identification of the new multimetal oxides.

In this context it should be noted that after this observation a another characteristic of the Cu-Kα powder X-ray diffraction spectrum of the multimetal oxides I used according to the invention to lie therein  appears to contain no high resolution diffraction lines, whose FWHM is <0.25 °.

The powder X-ray tube was recorded in all of the exemplary embodiments spectrum with a Siemens diffractometer D-5000 using Cu-Kα radiation (40 kV, 30 mA, λ = 1.54178 Å). The diffractometer was with an automatic primary and secondary beam diaphragm and with a graphite Secondary monochromator equipped.

Of course, the resolution, and thus an alternative characterization of the powder X-ray diffraction spectrum of the multimetal oxides I used in accordance with the invention, can be obtained by subtracting the linear diffraction under the boundary condition of a minimal mean square deviation from the experimental diffraction spectrum (its outline) by a mathematical one Describes the function and transforms it into a superposition of separately resolved lines A ¹ * to A ¹⁰ *. The maximum of the resolved lines defines their line position.

The mathematical resolution of the powder X-ray as described above Diffraction spectra were carried out with the soft provided by Siemens goods package DIFFRAC-ATV3.2 / PROFILE in the version from 1994, whereby the Unfolding and adaptation based on the Pearson VII design restriction was taken.

While the presence of the diffraction lines A ² , A ⁴ and A ⁶ to A ⁸ in the Cu-Kα powder X-ray diffraction spectra of the multimetal oxides I used in accordance with the invention is partly subject to a certain degree of uncertainty on the basis of an exclusively visual examination of their outline and is therefore possibly controversial (cf. ex.), the mathematical resolution generated as described above usually shows diffraction lines A ² *, A ⁴ *, A ⁶ * and A ⁷ * (cf. ex.), whereas they show a diffraction line A ⁸ * not required. The Cu-Kα powder X-ray diffraction spectrum of the multimetal oxides I used according to the invention can generally be characterized as mathematically resolved as follows:

I _F rel [%] is the percentage line intensity related to the most intense of the diffraction lines A ¹ * to A ¹⁰ *, the area under the diffraction line being used as the intensity measure.

Burn-off moderators from the multimetal oxides used according to the invention general formula I lead to improved combustion behavior in Comparison with combustion moderators, which consist of the correspondingly composed Oxide mixtures exist. In addition, combustion moderators from the Multimetal oxides of general formula I used according to the invention improved combustion behavior compared to molybdenum-vanadium Mixed oxides of appropriate composition, one of the invention used multimetal oxides I deviating atomic spatial order and thus have a different powder X-ray diffraction spectrum. Burn moderators show an improved burn-off behavior in particular if this burns out finally from the multimetal oxides according to the invention of the general formula I exist. But also combustion moderators that are only partially, e.g. B. 5 to 99, or 20 to 80% by weight of the multimetal oxide used according to the invention the powder X-ray diagram described and z. B. further crystalline, Molybdenum-vanadium mixed oxides with another powder X-ray diagram contain lead to an improved burning behavior.

The multimetal oxides I used according to the invention are simple obtainable by obtaining their elementary constitution from suitable sources ducks produces an intimate, preferably finely divided, dry mixture, that corresponds to the desired stoichiometry, and this at temperatures in Calcined range from 150 to 500 ° C. The redox character of the calculations atmosphere is preferably not to be oxidized and not to be reduced.  

The required redox character varies on the one hand with the chosen stoichiometry, and on the other hand, for example, the counterions (e.g. NH ₄ ⁺) of the selected sources of the element constituents, e.g. B. at their decomposition during calcining, to the redox character of the calcination atmosphere. However, the person skilled in the art can determine the required redox character of the calcination atmosphere by means of preliminary tests.

To control the redox character of the calcination atmosphere are available to the specialist as inert gases z. B. N ₂ and / or noble gases, as reducing gases z. B. ammonia, hydrogen, low molecular weight aldehydes and / or hydrocarbons and as an oxidative gas oxygen (usually in the form of air).

The element sources are preferably oxides, compounds which can be converted into oxides by heating, at least in the presence of oxygen. In addition to the oxides, halides, nitrates, formates, citrates, oxalates, acetates, carbonates or hydroxides are therefore particularly suitable as starting compounds. Suitable starting compounds for Mo, V, W and Nb are also their oxo compounds (molybdates, vanadates, tungstates and niobates), which generally have NH ₄ ⁺ as a counter ion, which releases NH ₃ with a reductive effect when heated. Of course, the acids derived from these oxo compounds can also be considered as possible starting compounds. In addition, compounds such as ammonium acetate and ammonium nitrate are often added to the element sources, which control the fine particle size of the powder obtained during the calcination and likewise influence the redox character of the calcination atmosphere.

The intimate mixing of the starting compounds in the course of production of multimetal oxides I can take place in dry or in wet form. He follows  it in dry form, the starting compounds are conveniently called finely divided powder used and after mixing and, if necessary, compression subjected to the calcination. The intimate mixing is preferably carried out however in wet form. Usually the starting compounds are used mixed together in the form of an aqueous solution and / or suspension. On finally the aqueous mass is dried and calcined after drying. The drying process is preferably carried out immediately after the fermentation the aqueous mixture is spray dried (the entry temperature is usually 250 to 350 ° C and the outlet temperature is more normal as at 100 to 150 ° C).

In the case of a preferably used multimetal oxide I, the spatial arrangement corresponds to that of the multimetal oxide Mo _8.54 V _2.47 W _0.99 O _33.35 , and it can be obtained by the process indicated in the examples for MI1.

The catalytically active material is preferably of a particle diameter in the range from <0 to 300 µm, preferably 0.1 to 200 µm, especially before attracts 0.5 to 50 microns, ground.

The multi metal oxides I show particularly advantageous properties as a combustion moderator if they are combined with at least one multimetal oxide of the general formula II

M ³ ₁₂ Cu _d H _e O _y (II)

With
M ³ = Mo, W, V, Nb and / or Ta,
d = 4 to 30, preferably 6 to 24, particularly preferably 9 to 17,
e = 0 to 20, preferably 0 to 10 and
y = a number which is determined by the valency and frequency of the elements in II other than oxygen,

used in a mixture. In this way, at least two-phase multimetal oxide compositions of the general formula III are preferably produced

[A] _p [B] _q (III),

in which the variables have the following meaning:

A = (Mo _12.abc V _a M ¹ _b M ² _c O _x ). (12 / (12-abc)) (active phase),
B = M ³ ₁₂ Cu _d H _e O _y (promoter phase),
p, q = non-zero numbers whose ratio p / q is 200: 1 to 1: 100, preferably 20: 1 to 1:10 and particularly preferably 15: 1 to 4: 1,

the portion [A] in the form of three-dimensionally extended regions A of the chemical composition which are delimited from their local environment on account of their chemical composition which is different from their local environment

Mo _12-abc V _a M ¹ _b M ² _c O _x

and the proportion [B], in the form of three-dimensionally extended regions B of the chemical composition which are delimited from their local environment on account of their chemical composition which is different from their local environment

M ³ ₁₂ Cu _d H _e O _y

included, the areas A, B preferably relative to each other as in a mixture of finely divided A and finely divided B are distributed.

The spatial arrangements of areas A preferably correspond to that of Multimetal oxide I.

The simplest way to produce such multimetal oxide materials III before the multimetal oxides I and II separately and then generated from at least one finely divided, separately pre-formed multimetal oxide I and at least one finely divided, separately preformed multimetal oxide II in desired intimate dry mix. The intimate mixture s can be done in dry or wet form. If it is wet, usually aqueous, is then dried. The mixing can be effected by kneaders or mixers.

In addition, he can manufacture the multimetal oxide materials III follow that first one of the multimetal oxides I or II separately prepared then this with suitable sources of the elementary constituents of the other, not preprepared multimetal oxide I or II to one if possible intimate, preferably finely divided dry mix is processed, and this is then calcined at temperatures in the range of 150 to 500 ° C.  

The multimetal oxide materials III can also be prepared by that suitable sources of the elementary constituents of the multimetal oxides I and II ver to an intimate, preferably finely divided dry mixture be worked, and then this at temperatures in the range of 150 is calcined to 500 ° C.

In the case of separate preparation of the multimetal oxides II, these can be prepared in a simple manner known to the person skilled in the art, for Example, be prepared by generating an intimate, preferably finely divided, dry mixture from suitable sources of their elemental constituents and calcining them at temperatures of 150 to 1000 ° C, often 250 to 600 ° C, often 300 to 500 ° C, wherein calcination under inert gas (e.g. N ₂ ), a mixture of inert gas and oxygen (e.g. air), reducing gases such as hydrocarbons (e.g. methane), aldehydes (e.g. acrolein) or ammonia , but also under a mixture of O ₂ and reducing gases (z. B. all of the above), as described for example in DE-A 4 335 973. The calcination atmosphere can also include water vapor. When calcining under reducing conditions it should be noted that the metallic constituents are not reduced to the element. The calcination time generally decreases with increasing calcination temperature.

Regarding the sources of the elementary constituents of the multimetal oxides II applies essentially the same as for the sources of the elementary constitutions ten of the multimetal oxides I. Here too, oxides or such compounds are preferred bindings used by heating, at least in the presence of acid substance that can be converted into oxides. In a preferred manufacturing variant of Multimetal oxide II is the thermal treatment of the intimate mixture of  used starting compounds in an autoclave in the presence of over atmospheric water vapor at temperatures <100 up to 600 ° C.

Depending on the chosen compositions and calcination conditions the resulting multimetal oxides II different atomic spatial arrangements on. In particular, the multimetal oxides come for the present invention II into consideration, which in DE-A 4 405 514, DE-A 4 440 891 and DE-A 195 28 646 describes as a possible key phase or promoter phase are. That is, cheap multimetal oxides II are u. a. those that have the structure type (the X-ray diffraction patterns) at least one of those in Table 1 below copper molybdate listed (the expression in brackets gives the Source for the associated X-ray diffraction fingerprint again):

Table 1

For the production of multimetal oxide masses III which are particularly suitable as combustion moderators, multimetal oxides II are those of the general formula IV

CuMo _A W _B V _C Nb _D Ta _E O _Y. (H ₂ O) _F (IV)

With
1 / (A + B + C + D + E) = 0.7 to 1.3,
F = 0 to 1,
B + C + D + E = 0 to 1 and
Y = a number which is determined by the valency and frequency of the elements other than oxygen in IV,

whose atomic spatial arrangement corresponds to the structure type, which is defined by the CuMoO ₄ -III compound in Russian Journal of Inorganic Chemistry 36 (7), 1991 on p. 921 in Table 1 and in DE-A 4 405 514 and DE- A 4 440 891 is called tungsten.

Amongst the multimetal oxides IV are those of stoichiometry V

CuMo _A W _B V _C O _Y (V)

With
1 / (A + B + C) = 0.7 to 1.3,
A, B, C = all <0, with the proviso that B + C ≦ 1,
Y = a number which is determined by the valency and frequency of the elements in V other than oxygen,
as well as those of stoichiometry VI

CuMo _A W _B O _Y (VI),

With
1 / (A + B) = 0.7 to 1.3,
B / A = 0.01 to 10, preferably 0.01 to 1, and
Y = a number which is determined by the valency and frequency of the elements other than oxygen in VI,

to emphasize. The manufacture of multimetal oxides IV, V and VI disclose DE-A 44 05 514 and DE-A 44 40 891.

Other particularly suitable multimetal oxides II are those of the general formula VII,

CuMo _A , W _B , V _C , Nb _D , Ta _E , O _Y (VII),

With
1 / (A '+ B' + C '+ D' + E ') = 0.7 to 1.3, preferably 0.85 to 1.15, particularly preferably 0.95 to 1.05 and very particularly preferably 1 ,
(B '+ C' + D '+ E') / A '= 0.01 to 10, preferably 0.05 to 3 and particularly preferably 0.075 to 1.5 and
Y = a number which is determined by the valency and frequency of the elements other than oxygen in VII,

whose structure type is the HT-Cu molybdate type disclosed in DE-A-195 28 646  is.

Among the multimetal oxides VII, those with C '+ D' + E '= O are preferred. A particularly recommended multimetal oxide VII is that of the composition Mo _10.8 W _1.2 Cu ₁₂ O _42-48 .

Mixtures of multimetal oxides are also possible multimetal oxides II IV and VII to name as they are also disclosed in DE-A-195 28 646. This applies in particular to those mixtures which contain the multimetal oxides IV and VII contained in an overgrown form.

Of course, the mixture generated from multimetal oxides I and II can be used its use for the preparation of multimetal oxide mass III catalysts also pressed first, then ground.

The multimetal oxides I are also generally suitable for combination with Multimetal oxide materials as described in DE-A 4 335 973, US-A 4 035 262, DE-A 44 05 058, DE-A 44 05 059, DE-A 44 05 060, DE-A 44 05 514, DE-A 44 40 891 and DE-A 195 28 646 are described.

The multimetal oxides I are particularly suitable as part of the Co-phases of the in DE-A 44 05 058, DE-A 44 05 059, DE-A 44 05 060, DE-A 44 05 514 and DE-A 44 40 891 disclosed multi-phase multimetal oxide masses. The multimetal oxides I are also suitable as a component of the active phase of the multi-phase multimetal oxide materials of DE-A 195 28 646. In these Cases arise multiphase multimetal oxide masses, the phases from multimetal oxides I in a finely divided (<0 to 300 µm) homogeneous distribution.  

In a simple manner, z. B. the active compositions described there in finely divided form mixed with finely divided multimetal oxides I and like that intimate starting mixture for the production of multimetal oxide III catalyst gates shaped.

Alternatively, the multimetal used according to the invention can be produced oxide masses take place in that suitable sources of the elementary constitutions ten of the multimetal oxide I together with suitable sources of the elementary Constituents of the other multimetal oxide masses to create the most intimate preferably fine-particle dry mix are processed, and this on finally calcined at temperatures in the range of 150 to 500 ° C.

The invention also relates to a combustion moderator containing at least 5 preferably at least 20, particularly preferably at least 50% by weight at least one multimetal oxide of the general formula I and / or at least a mixture thereof with at least one multimetal oxide of the general Formula II and / or at least one two-phase multimetal oxide mass general formula III.

In addition, other crystalline molybdenum-vanadium mixed oxides and / or MoO ₃ and / or V ₂ O _{5 can} be present, for example in amounts of 1 to 95 or 20 to 80% by weight.

GAS GENERATING MIXTURES

The combustion moderators according to the invention are preferably used in gas generators Mixtures used in airbag systems or rocket propellants be set.  

Such gas generating mixtures according to the invention comprise a nitrogen rich fuel, which may contain an oxidizer, and 0.02 to 10% by weight, preferably 0.5 to 5 wt .-%, based on the gas-generating mixture, min least a combustion moderator, as described above.

According to one embodiment of the invention, the gas generating mixture is based on a nitrogen-rich and low-carbon fuel, for example is selected from nitroguanidine (NIGU), triaminoguanidine nitrate (TAGN), Digua nidium-5,5'-azotetrazolate (GZT), 3-nitro-1,2,3-triazol-5-one (NTO) and mixtures from that. Diguanidinium-5,5'-azotetrazolate (GZT) is particularly advantageous. used because both the starting substance and the resulting gases far are largely non-toxic and mainly consist of nitrogen. Around the burning properties for use, for example, in airbag systems to adapt, the fuel is combined with at least one oxidizer and a combustion moderator according to the invention used.

Copper diammine dinitrate (Cu (NH ₃ ) ₂ (NO ₃ ) ₂ ), for example, can be used as the oxidizer. By varying the amount of oxidizer, the combustion behavior of the gas-generating mixture can be adjusted over a wide range, so that a high combustion rate can be achieved. A maximum pressure builds up within a few milliseconds while the combustion temperature remains low, so that thermally sensitive bag materials are not destroyed, particularly in airbag systems.

The combustion moderator according to the invention can be more active during combustion Reaction component that can be implemented and reactive has a steering or reaction-accelerating effect. This can be upset Absorption and delivery capacity of the catalyst are recycled, the  thus acts as an effective oxygen carrier. For a balanced ab The combustion moderator according to the invention can react to fire Size diameters listed up to 300 µm, preferably have 1 to 30 µm.

The system of combustion moderator, oxidizer and fuel fulfills this thermo-mechanical stability requirements, for example on airbag propellants sentences are put. In addition, the gas-generating according to the invention Mixture is not hygroscopic, which is permanent functionality and high Ensures lifespan.

The combustion moderator is preferably used in an amount of 0.02 to 10 Wt .-%, preferably 0.5 to 5 wt .-%, based on the gas-generating Mi research, used. The weight ratio between fuel and oxidizer is preferably 10: 1 to 1:10, particularly preferably 1: 1 to 1: 5.

The oxygen balance between fuel and oxidizer is preferably balanced chen, d. H. there is neither excess fuel nor after the combustion excess oxidizer before.

The gas-generating mixture can contain other suitable additives, such as coolants. Fe ₂ O ₃ can be used as the coolant.

The on nitrogen-rich and low-carbon fuels as described above based gas-generating mixtures are thermal mechanically insensitive, largely non-toxic, and that when burned resulting gases are largely non-toxic and largely free of coal mo oxide and nitrogen oxides. Suitable fuels are for example in the DE C1 44 42 169 described.  

According to one embodiment of the invention, ammonium is used as fuel nitrate used in pure or phase-stabilized form. The phase stabilization can be achieved with nickel oxide, potassium or cesium nitrate.

Nickel oxides are preferably present in amounts of 1 to 7% by weight, potassium or cesium nitrate in amounts of 3 to 15% by weight, based on the amount of ammonium nitrate, contained in the fuel. They serve to stabilize the Crystal phases of ammonium nitrate and suppress larger volume changes against the oxidizer grains.

Suitable gas-generating mixtures based on ammonium nitrate, which he can be used according to the invention are, for example, in EP-A1-0 705 809 described.

Gas-generating mixtures based on ammonium nitrate have in the Usually a low burning rate and a high pressure exponent on. The burning rate can be increased by adding energy-rich substances, such as octogen or hexogen, of metals or of ener greedy binders. The high-energy binders include, for example Isocyanate-bound glycidyl azidopolymer (GAP), nitrate ester-containing polymers, such as polyglycidyl nitrate and polynitratomethylethyloxetane, and nitroamino-sub substituted polymers.

The binder can be on a binder polymer and a high-energy Plasticizers based. The binder polymer can be inert and is preferred an isocyanate-hardened bi- or trifunctionally hydroxy-substituted polyester or polyether prepolymer. It can also be a corresponding glycidyl azide polymer be used. The plasticizer, which is preferably high in energy, is  preferably selected from the group of nitrate esters, nitro, nitroamino or acid softeners. Trimethyl in particular can be used as the nitrate ester olethane trinitrate (TMETN), butanetriol trinitrate (BTTN) or ethylene glycol dinitrate (DEGDN) can be used.

Nitro plasticizers are, for example, mixtures of bisdinitropropyl formal / acetal (BDNPF / A). Nitroamino plasticizers are, for example, mixtures of N-ethyl and N-methylnitratoethylnitroamine (EtNENAMeNENA) or N-butyl-N-Nitrato methylnitroamine (BuNEA) or N, N'-dinitratoethylnitroamine (DINA).

Bisazido-terminated GAP oligomers are examples of azide softeners (GAP-A) or 1,5-diazido-3-nitroaminopentane (DANPD) can be used.

The weight ratio of polymer to plasticizer is preferably in the loading range from 1: 3 to 20: 1. However, the binder polymers can also be in pure form be used. Especially for applications in gas generator propellants, Like airbags, lower-energy formulations are suitable, the higher Binder content included. The binder system can range from 15 to 50 % By weight, based on the total amount of the gas-generating mixtures be set. The proportion of ammonium nitrate or phase stabilized lized ammonium nitrate 10 to 80 wt .-%, the proportion of inventive Burn moderator 0.02 to 10 wt .-%. The content is particularly preferably on ammonium nitrate or phase-stabilized ammonium nitrate 35 to 80 % By weight, in particular 50 to 80% by weight. Can be used as further additives high-energy substances, such as nitramines, for example hexogen (RDX) or Octogen (HMX) preferably in amounts of 1 to 4 wt .-%, based on the total weight of the gas-generating mixture can be used.  

Furthermore, metals such as aluminum, magnesium or boron can be used as a constituent the gas-generating mixture can be used. When using it is the proportion preferably 0.5 to 20 wt .-%, based on the total weight the gas generating mixture.

Stabilizers can also be added to the gas-generating mixture, which can act as nitrogen oxide and acid scavengers. Are preferred here Diphenylamine, 2-nitrodiphenylamine, N-methylnitroaniline, or mixtures thereof used. The amount is preferably 0.4 to 2 wt .-%, based on the total weight of the gas generating mixture.

The combustion moderators according to the invention can, if appropriate, together be used with carbon black or graphite.

The ammonium nitrate can also be an anti-caking agent such as silica gel, tri calcium sulfate, sodium lauryl sulfonate, or other surfactants.

In both embodiments of the invention, the Ab fire moderators with other metal oxides, such as Ag, Ni, Fe or Co or mixtures thereof are used. You can, for example as a mixture with known mixed oxides of the aforementioned metals be used. Suitable multimetal oxide materials, for example copper and containing nickel are given in the patents listed above ben. Combinations with other known mixed oxides are possible.

Furthermore, the gas-generating mixtures according to the invention can contain metal carbides or nitrides, preferably silicon and zirconium carbide in small amounts, for example 0.1 to 1 wt .-%, based on the total weight of the gas  mixture.

The gas-generating mixtures according to the invention can be used in a large number of Applications are used. For example, they are used in gas generator propulsion sets, such as used in airbag systems. You can also rescue systems, fire extinguishing devices and other inflatable devices and Systems are used. They can also be used as missile and pipe weapons drives are used. Further uses are known to the person skilled in the art.

The invention thus also relates to airbag propellants and rocket propellants comprise a gas generating mixture according to the invention.

The invention is illustrated below with examples of the erosion modera gates explained. Examples of the other components of the gas-generating Mixtures can be found in EP-A1-0 705 809 and DE-C1 44 42 169 will.

The examples will be explained additionally with reference to the drawing which comprises Figs. 1 to 16.

Examples 1) Production and identification of used according to the invention Multimetal oxides MI1 to MI9 General

The multimetal oxides I used according to the invention described below contain the elemental constituents Mo and W in the oxidation state +6. The oxidation state of the elemental constituent V, on the other hand, is generally a distribution over its possible oxidation states V ³⁺ , V ⁴⁺ and V ⁵⁺ . The determination of this distribution was possible by titrimetric measurement analysis with potentiometric end point display (combined platinum electrode and potentiograph from Metrohm, 9100 Herisau, Switzerland), working under an inert gas atmosphere. Carrying out the titration at 80 ° C made it easier to identify the end point. In all other cases, the dimensional analysis was as follows:
Each 0.15 g of the oxidic sample material were dissolved in a mixture of 5 ml of concentrated phosphoric acid (mass density ρ at 20 ° C = 1.70 g / cm ³ ) and 10 ml of aqueous sulfuric acid with heating (atmosphere atmosphere), the used aqueous sulfuric acid solution was in turn a mixture of equal volumes of water and concentrated sulfuric acid (ρ ²⁰ = 1.52 g / cm ³ ) (the volume specifications relate to 20 ° C). The solvent was chosen so that it did not change the possible oxidation states of the V, which was checked by means of appropriate V standards.

For the analytical determination of the V ⁵⁺ content, the freshly prepared resulting solution was titrated with a 0.1 molar aqueous ammonium sulfate solution ((NH ₄ ) ₂ Fe (SO ₄ ) ₂ ). For the analytical determination of V ³⁺ and V ⁴⁺ , a freshly prepared solution was titrated with a freshly prepared 0.02 molar aqueous potassium permanganate standard solution (KMnO ₄ ), with two potential jumps occurring (V ³⁺ → V ⁴⁺ and V ⁴⁺ → V ⁵⁺ ). The sum of the V ³⁺ , V ⁴⁺ and V ⁵⁺ contents determined as described had to correspond to the total V content of the sample. This could also be determined by titrimetric measurement analysis with potentiometric end point display as follows.

For this purpose, 0.15 g of the oxidic sample material was dissolved in a mixture of 10 ml of the aforementioned semi-concentrated aqueous sulfuric acid and 10 ml of concentrated nitric acid (ρ ²⁰ = 1.52 g / cm ³ ) with heating (argon atmosphere). The solution obtained was then concentrated to a residual volume of about 3 ml by heating while nitric acid and part of the sulfuric acid used, the entire V content being converted to oxidation state +5. After cooling, the residual volume was diluted to 50 ml and the V ⁵⁺ contained was titrated potentiometrically with a 0.1 molar aqueous (NH ₄ ) ₂ Fe (SO ₄ ) ₂ solution above the equivalence point (end point).

The aqueous solution thus obtained was titrated with a freshly prepared 0.02 molar aqueous potassium permanganate standard solution, two potential jumps occurring. The first potential jump indicated the excess of Fe ^{2+ used} , the second potential jump provided the amount of KMnO ₄ required for the oxidation of V ⁴⁺ to V ⁵⁺ , which corresponds to the total V content of the sample.

example 1 MI1: Mo _8.54 V _2.47 W _0.99 O _33.53

33.746 kg ammonium heptamolybdate hydrate (MoO ₃ content: 81.8% by weight, ideal composition: (NH ₄ ) ₆ Mo ₇ O ₂₄ × 4H ₂ O), 6.576 kg ammonium metavanadate (V ₂ O ₅ content: 76.5% by weight) .-%, ideal composition: NH ₄ VO ₃ ), 5.764 kg ammonium paratungstate hydrate (WO ₃ content: 89.0% by weight, ideal composition: (NH ₄ ) ₁₀ W ₁₂ O ₄₁ × 7H ₂ O) and 7.033 kg ammonium acetate (CH ₃ COONH ₄ content: 97.0% by weight, ideal composition: CH ₃ COONH ₄ ) were dissolved in succession in a sequence of 90 ° C. in 250 l of water with stirring. The resulting yellow to orange solution was cooled to 80 ° C and spray dried with an inlet temperature of 300 ° C and an outlet temperature of 110 ° C.

800 g of the spray powder obtained were in a kneader (type LUK2.5 Werner and Pfleiderer, Stuttgart, DE) with a usable volume of 2.5 l kneaded for 1 h with the addition of 250 g of water. Of the 250 g Water 180 g within the first 10 minutes of kneading and 70 g within added to the remaining 50 minutes of kneading. The resulting damp and Plaice-shaped kneaded product was dried at a temperature of 110 ° C. for 15 h and then pressed through a sieve with a mesh size of 5 mm.

100 g of the resulting granules were then weighed right rotary kiln with an isothermally heated quartz ball volume of 1 and calcined at a rotational speed of 12 revolutions per minute.  

The calcination conditions were as follows:

• 1st step: the granules used continuously within 50 min Heat 25 to 275 ° C;
• 2nd step: the granules used continuously within 30 min Heat 275 ° C to 325 ° C;
• 3rd step: keep the granules used at 325 ° C for 4 h;
• 4th step: the granules used continuously within 30 min Heat 325 ° C to 400 ° C;
• 5th step: keep the granules used at 400 ° C for 10 min;
  The external heating of the rotary kiln was then switched off and the latter was cooled by blowing on it with ambient air. The granules used cooled to 25 ° C. in the course of 5 hours.

During the individual calcination steps, the interior of the rotary kiln was flown through parallel to the axis of rotation by gas mixtures which had the following compositions (normal conditions (N) = 1 atm, 25 ° C):

• 1st step, 2nd step and 3rd step:
  3.6 Nl / h air, 1.5 Nl / h NH ₃ and 44.9 Nl / h N ₂ (total gas flow: 50 Nl / h);
• 4th step, 5th step and cooling phase:
  3.6 Nl / h air and 44.9 m Nl / h N ₂ (total gas flow: 48.5 Nl / h).

The resulting powdered multimetal oxide MI1 had a black color and a specific surface area (determined according to DIN 66131 by gas adsorption (N ₂ ) according to Brunauer-Emmet-Teller (BET)) of 15.0 m ² / g. The vanadium contained in the multi-metal oxide MI1 was more than 99% V ⁴⁺ (the determination was carried out as described above). The multimetal oxide MI1 thus had the stoichiometry Mo _8.54 V _2.47 W _0.99 O _33.53 .

That determined in accordance with the explanations in the description and after deduction of the linear background evaluated Cu-Kα powder X-ray diffraction spectrum contained the following diffraction lines in the relevant 2θ range (5 ° to 50 °):

1. Visually resolved

2. Mathematically resolved

The experimentally determined Cu-Kα powder X-ray diffraction spectrum reflecting the atomic spatial arrangement of the multimetal oxide MI1 is shown in FIG. 1 (ordinate: intensity, given as an absolute count rate; abscissa: 2θ range from 5 ° to 65 °).

Furthermore, the Fig. 1 shows the in the analysis to be subtracted linear background (the connecting line between A (2θ = 5 °) and A (2θ = 65 °)), as well as the position of the individual diffraction lines A ^i. The points of contact between the baseline and the X-ray diffraction spectrum naturally divide the latter into the two 2θ ranges 5 ° to 43 ° and 43 ° to 65 °.

FIG. 2 shows an enlargement of the 2θ range 5 ° to 43 ° of the CU-Kα powder X-ray diffraction spectrum of the multimetal oxide MI1. Furthermore, FIG. 2 shows the result (including the background line) of the mathematical adjustment and resolution (PROFILE, Pearson VII profile function, fixed background) carried out for this area as described. The superposition of the mathematically generated diffraction lines A ⁱ * results in the adaptation to the experimental outline.

Fig. 3 shows in a corresponding manner, the enlarged 2θ range of 43 ° to 65 °, and the processing performed for this area development, including linear base line.

The rectangular section to be seen above the actual X-ray diffraction spectrum in FIGS . 2 and 3 each shows the difference line between the experimental outline of the powder X-ray diffraction spectrum and its mathematical adaptation. This difference is a measure of the quality of the adjustment.

Example 2 MI2: Mo _8.54 V _2.47 W _0.99 O _33.53

Granules were produced as for MI1. 400 g of the granules were calcined in a calcination furnace operating on the principle of a propulsion jet reactor. The granules used were at a bed height of 5 cm on a wire mesh, which was flown through from below with a gas mixture. The volume of the furnace was 3 l, the circulation ratio [(circulated gas mixture volume flow): (freshly supplied gas mixture volume flow)] was chosen to be 20. The granules used were first continuously heated from 25 ° C. to 325 ° C. in the oven mentioned within 1 h. The granules used were then kept at 325 ° C. for 4 h. At the beginning of the calcination, the gas mixture flowing through was composed of 120 Nl / h N ₂ , 10 Nl / h air and 3.3 Nl / h NH ₃ . Finally, the granules used were heated from 325 ° C to 400 ° C within 20 min and then held at 400 ° C for 1 h. In this final phase, a gas mixture of 120 Nl / h N ₂ and 10 Nl / h air was passed through. By switching off the heat supply, the mixture was cooled to room temperature.

A powdery multimetal oxide MI2 was obtained which was identical to the multimetal oxide MI1 with regard to the V ^{5 +, 4 + 3 +} analysis and with regard to its Cu-Kα powder X-ray diffraction spectrum.

Example 3 MI3: Mo _8.35 V _2.60 W _1.05 O _33.40

852.78 g ammonium heptamolybdate hydrate (MoO ₃ content: 81.0% by weight, ideal composition: (NH ₄ ) ₆ Mo ₇ O ₂₄ × 4 H ₂ O), 177.14 g ammonium metavanadate (V ₂ O ₅ content : 77.0% by weight, ideal composition: NH ₄ VO ₃ ) and 156.29 g of ammonium paratungstate hydrate (WO ₃ content: 89.0% by weight, ideal composition: (NH ₄ ) ₁₀ W ₁₂ O ₄₁ × 7 H ₂ O) were dissolved one after the other in 5 l water at a temperature of 95 ° C. The yellow to orange solution obtained was cooled to 80 ° C. and spray-dried at an inlet temperature of 300 ° C. and an outlet temperature of 110 ° C. 100 g of the spray-dried powder were then calcined in a horizontal rotating ball oven with an isothermally heated quartz ball volume of 1 l and a rotating speed of 12 revolutions per minute under the conditions defined below. In a first step, the powder used was continuously heated from 25 ° C to 275 ° C within 50 minutes, in a second step immediately following the first step, the powder used was continuously from 275 ° C to 325 within 30 minutes ° C heated, in a third step immediately following the second step, the powder used was held at 325 ° C for 4 hours and in a fourth step immediately following the third step, the powder used was within 3.5 hours of 325 ° C heated to 400 ° C. During the first three steps, a gas mixture consisting of 9.6 Nl / h air, 3 Nl / h NH ₃ and 87.4 Nl / h N ₂ (total gas flow: 100 Nl / h) was flowed through the quartz ball. During the fourth step, a gas mixture consisting of 9.6 Nl / h air and 87.4 Nl / h N ₂ (total gas flow = 97 Nl / h) was flowed through the quartz ball. After the fourth step, the external heating of the rotary kiln was switched off and cooled by blowing air from the outside. The powder used cooled under the gas mixture of 9.6 Nl / h air and 87.4 Nl / h N ₂ flowing through the quartz ball unchanged to 25 ° C within 5 hours.

The resulting powdered multimetal oxide MI3 had a black color and a specific surface area (DIN 66131) of 0.5 m ² / g. The vanadium contained in the multi-metal oxide MI3 was more than 99% V ⁴⁺ . The MI3 multimetal oxide thus had the stoichiometry Mo _8.35 V _2.60 W _1.05 O _33.40 .

The associated Cu-Kα powder X-ray diffraction spectrum is shown in FIGS. 4 to 6. It shows the atomic spatial arrangement common to MI1. His evaluation, as carried out for MI1, showed the following diffraction lines in the relevant 2θ range.

1. Visually resolved

2. Mathematically resolved

Example 4 MI4: Mo _8.35 V _2.60 W _1.05 O _33.40

As for MI3, a spray dried powder was created. 60 g of the spray-dried powder were then calcined in a horizontal rotary ball oven with an isothermally heated quartz ball volume of 1 l and a speed of 12 revolutions per minute under the conditions defined below. In a first step, the powder used was heated from 25 ° C. to 275 ° C. within 50 minutes, in a second step immediately following the first step, the powder used became continuously from 275 ° C. to 325 ° C. within 30 minutes heated, in a third step immediately following the second step, the powder used was held at 325 ° C. for 3 hours and in a fourth step immediately following the third step, the powder used rose from 325 ° C. within 90 minutes 400 ° C heated and then held at 400 ° C after 10 minutes. During the first 3 steps, a gas mixture consisting of 4.8 Nl / h air, 1.5 Nl / h NH ₃ and 43.7 Nl / h N ₂ (total gas flow: 50 Nl / h) was flowed through the quartz ball. During the fourth and fifth steps, a gas mixture consisting of 4.8 Nl / h air and 43.7 Nl / h N ₂ (total gas flow: 48.5 Nl / h) was flowed through the quartz ball. After completion of the fifth step, the external heating of the rotary ball oven was switched off and cooled by blowing air from the outside. The powder used cooled under the gas mixture of 4.8 Nl / h air and 43.7 Nl / h N ₂ flowing through the quartz ball unchanged to 25 ° C within 5 hours.

A powdery multimetal oxide MI4 was obtained which was the same as the multimetal oxide MI3 with regard to the V ⁵⁺ , V ⁴⁺ , V ³⁺ analysis and with regard to its CU-Kα powder X-ray diffraction spectrum. The quantitative evaluation of the X-ray diffraction spectrum carried out as described (shown in FIGS . 7 to 9) gave in the relevant 2θ range:

1. Visually resolved

2. Mathematically resolved

Example 5 MI5: Mo _8.54 V _2.47 W _0.99 O _33.01

800 g of the spray powder produced for the production of MI1 were mixed in one Kneader (type LUK 2.5 from Werner and Pfleiderer, Stuttgart, DE) with one  Usable volume of 2.5 l with the addition of 80 g acetic acid (100%) and 200 kneaded g of water for 1 h. This was kneading during the first 10 minutes added the 80 g acetic acid and 80 g water. The remaining 120 g of water kneading was added during the remaining 50 minutes. The resulting moist and clod-shaped kneaded product was 15 h at a temperature of Dried 110 ° C and then through a sieve with a mesh size of 5 mm pressed. 100 g of the resulting granules were then in one horizontal rotary kiln calcined as described for MI1.

The resulting powdery multimetal oxide MIS had a black color and a specific surface area (DIN66131) of 16.0 m ² / g. The vanadium contained in the multimetal oxide MIS was 42% V ³⁺ and 58% V ⁴⁺ . In contrast to the multi-metal oxide MI1, the multimetal oxide MIS therefore had the stoichiometry Mo _8.54 V _2.47 W _0.99 O _33.01 . The CU-Kα powder X-ray diffraction spectrum determined and evaluated as for the multimetal oxide MI1 nevertheless reflected the same atomic spatial arrangement for the multimetal oxide MIS as for the multimetal oxide MI1 (cf. FIGS. 10 to 12). The determined diffraction lines in the relevant 2θ range are:

1. Visually resolved

2. Mathematically resolved

Example 6 MI6: Mo _9.6 V _2.4 O _34.37

At 80 ° C, 239.74 g of oxalic acid dihydrate (ideal composition: H ₂ C ₂ O ₄ × 2 H ₂ O, H ₂ C ₂ O ₄ content: 71.4% by weight) were placed in 4 l in a first vessel Water dissolved. Subsequently, while maintaining the 80 ° C. in the resulting aqueous solution, 90.22 g of ammonium polyvanadate (V ₂ O ₅ content: 88.2% by weight, ideal composition: (NH ₄ ) ₂ V ₆ O ₁₆ were dissolved while stirring a deep blue aqueous solution A. The ammonium polyvanadate was added in small portions over the course of 15 minutes to prevent the reaction mixture from foaming over. 619.60 g of ammonium heptamolybdate hydrate (MoO ₃ content: 81.3% by weight) were placed in a second vessel. %, Ideal composition: (NH ₄ ) ₆ Mo ₇ O ₂₄ × 4H ₂ O) dissolved in 4 l of hot water at 80 ° C. with stirring (solution B), and solution B was then continuously introduced into the solution at 80 ° C. over the course of 15 minutes Solution A stirred in. The resulting deep blue aqueous solution was stirred for a further 15 h at 80 ° C. and then spray-dried (inlet temperature: 310 ° C., outlet temperature: 110 ° C.).

100 g of the spray dried powder was made in a horizontal rotation Ball oven with an isothermally heated quartz ball volume of 1 l and one Rotation speed of 12 revolutions per minute under the following Calcined conditions. In a first step, the powder used heated continuously from 25 ° C to 275 ° C within 50 minutes, in a second step immediately following the first step was the powder used continuously within 35 minutes 275 ° C heated to 325 ° C and in an immediately following third step held at 325 ° C for 4 h. Immediately afterwards that was powder used in a fourth step within 35 minutes of 325 ° C. heated to 400 ° C and in a immediately following fifth Step kept at 400 ° C for 10 minutes. Then the outer The heating of the rotary ball oven is switched off and the quartz ball is turned on blow cooled with air. The powder used cooled inside from 5 h to room temperature (25 ° C). Throughout the Calcina duration (including the cooling phase), the quartz ball was Air flow of 50 Nl / h.

The resulting powdered multimetal oxide MI6 had a black color and a specific surface area (DIN 66131) of 6.6 m ² / g. The vanadium contained in the multi-metal oxide MI6 was 36% V ⁴⁺ and 64% V ⁵ +. The multimetal oxide MI6 thus had the stoichiometry Mo _9.6 V _2.4 O _34.37 .

The visual appearance of the associated CU-Kα powder X-ray diffraction spectrum corresponded to that of MI1 (see FIG. 13) and indicated the atomic spatial arrangement common to MI1. His evaluation, as carried out for MI1, gave the following diffraction lines in the relevant 2θ range:

1. Visually resolved

2. Mathematically resolved

Example 7 MI7: Mo _9.6 V _2.4 O _34.13

100 g of the spray-dried powder prepared for MI6 were mixed in one horizontal rotary ball furnace with an isothermally heated quartz ball volume of 1 l and a speed of 12 revolutions per minute under the  following conditions calcined. In a first step it was powder used heated from 25 ° C to 275 ° C within 50 min, in a second step immediately following the first step was the powder used continuously within 25 minutes 275 ° C heated to 300 ° C and in an immediately following third step was the powder used for 4 h at 300 ° C. held. Then the external heating of the rotary kiln switched off and the rotating ball cooled by blowing with air. Here the powder used cooled to room temperature (25 ° C) within 3 h from. During the entire calcination period (including the cooling phase) the quartz ball was flowed through by a 50 Nl / h air flow.

The resulting powdered multimetal oxide MI7 had a black color and a specific surface area (DIN66131) of 5.7 m ² / g. The vanadium contained in the multi-metal oxide MI6 was 56% V ⁴⁺ and 44% V ⁵ +. The multimetal oxide MI7 thus had the stoichiometry Mo _9.6 V _2.4 O _34.13 .

The visual appearance of the associated Cu-Kα powder X-ray diffraction spectrum corresponded to that of MI1 (cf. FIG. 14) and thus indicated the atomic spatial arrangement common to MI1. His evaluation, as carried out for MI1, gave the following diffraction lines in the relevant 2θ range:

1. Visually resolved

2. Mathematically resolved

Example 8 MI8: Mo _9.0 V _3.0 O _33.72

At 80 ° C., 306.86 g of oxalic acid dihydrate (ideal composition: H ₂ C ₂ O ₄ × 2 H ₂ O, H ₂ C ₂ O ₄ content: 71.4% by weight) were dissolved in 4 water in a first vessel . Subsequently, while maintaining the 80 ° C. in the clear aqueous solution, 115.48 g of ammonium polyvanadate (V ₂ O ₅ content: 88.2% by weight, ideal composition: (NH ₄ ) ₂ V ₆ O ₁₆ ) were dissolved with stirring, a deep blue aqueous solution was formed (solution A). The ammonium polyvanadate was added in small portions over the course of 15 minutes in order to avoid over-foaming of the reaction mixture. In a second vessel, 594.82 g of ammonium heptamolybdate hydrate (MoO ₃ content: 81.3% by weight, ideal composition: (NH ₄ ) ₆ Mo ₇ O ₂₄ × 4 H ₂ O) were immersed in 4 l of 80 ° C. hot water Stir dissolved (solution B). Subsequently, the solution B was continuously stirred into the solution A at 80 ° C. within 15 minutes. The resulting deep blue aqueous solution was stirred for a further 15 h at 80 ° C. and then spray-dried (inlet temperature: 310 ° C., outlet temperature: 110 ° C.).

100 g of the spray dried powder were placed in a horizontal rotating ball furnace with an isothermally heated quartz ball volume of 1 l and a rotary speed of 12 revolutions per minute as described for MI7 in Airflow calcined.

The resulting powdered multimetal oxide MI8 had a black color and a specific surface area (DIN 66131) of 5.3 m ² / g. The vanadium contained in the multimetal oxide MI8 was 52% V ⁴⁺ and 48% V ⁵⁺ . The MI8 multimetal oxide thus had the Mo _9.0 V _3.0 O _33.72 stoichiometry. The visual appearance of the associated CU-Kα powder X-ray diffraction spectrum corresponded to that of MI1 (cf. FIG. 15) and accordingly showed an atomic spatial arrangement common to MI1. His evaluation, as carried out for MI1, gave the following diffraction lines in the relevant 2θ range:

1. Visually resolved

2. Mathematically resolved

Example 9 MI9: Mo _9.0 V _3.0 O _34.04

100 g of the spray-dried powder produced for MI8 were calcined in an air flow in a horizontal rotary ball oven with an isothermally heated quartz ball volume of 1 l and a rotation speed of 12 revolutions per minute as described for MI6. The resulting multimetal oxide MI9 had a black color and a specific surface area (DIN 66131) of 5.7 m ² / g.

The vanadium contained in the multimetal oxide MI9 was 31% V ⁴⁺ and 69% V ⁵⁺ . The M19 multimetal oxide thus had the stoichiometry Mo _9.0 V _3.0 O _34.04 . The visual appearance of the associated CU-Kα powder X-ray diffraction spectrum ( FIG. 16) corresponded to that of MI1 and showed the atomic spatial arrangement common to MI1. His evaluation, as carried out for MI1, gave the following diffraction lines in the relevant 2θ range:

1. Visually resolved

2. Mathematically resolved

2) Production of multimetal oxides II Example MII1 MII1: Starting mass 1 (Cu ₁₂ Mo ₁₂ O ₄₈ ) from MS of DE-A 44 40 891 was reworked

55.3 g of Cu (II) oxide (CuO, Merck, Darmstadt, purest, at least 96%, powdery) and 100.0 g of Mo (VI) oxide (MoO ₃ , Merck , Darmstadt, pa, at least 99.5% 'powder) dispersed. The total amount of the aqueous dispersion was heated in an autoclave (material: Hastelloy C4; internal volume: 2.5 l) to 350 ° C. with stirring (1000 revolutions per minute) and kept at this temperature and the associated excess pressure for 24 hours with stirring. The car was then cooled to room temperature, the aqueous dispersion contained therein removed, the dispersed solid filtered off and then dried in a drying cabinet at 80.degree. The resulting dry powder showed crystalline particles with a number average grain size diameter of about 8 µm in the scanning electron microscopic examination (SEM). Chemical analysis of the crystalline particles showed a Cu / Mo ratio of approx. 1.

Using CU-Kα radiation (Siemens diffractometer D-5000, 40 kV, 30 mA, with automatic divergence, scattering beam and counter tube diaphragm and pellet detector), the crystalline powder CuMoO _y showed the following X-ray diffraction pattern, reproduced in the form of network plane distances d [Å] which are independent of the wavelength of the X-rays used, as well as the associated relative intensities (%) of the various diffraction lines related to the most intense (amplitude) diffraction line:

The inaccuracy in the specification of the network plane spacing d amounts to ± 0.20 Å (the low-intensity lines presumably also include lines due to minor impurities). This X-ray diffraction pattern corresponds to that for CuMoO ₄ -III in Russian Journal of Inorganic Chemistry 36 (7), 1991, p. 927, Table 1.

Example MII2

MII2: Starting mass 1 (Cu ₁₂ Mo ₆ W ₆ O _42-48 ) from M3 of DE-A 195 28 646 was reworked: 223.05 g ammonium heptamolybdate hydrate (MoO ₃ content: 81.3% by weight, ideal composition: ( NH ₄ ) ₆ Mo ₇ O ₂₄ × 4 H ₂ O) and 327.52 g ammonium paratungstate hydrate (WO ₃ content: 89.2% by weight, ideal composition: (NH ₄ ) ₁₀ W ₁₂ O ₄₁ × 7H ₂ O ) were dissolved in 5 l of water at 90 ° C. with stirring (solution A). 492.64 g of copper acetate hydrate (Cu content: 32.5% by weight, ideal composition: Cu (CH ₃ COO) ₂ × H ₂ O) were mixed with 3 l of water and 197.88 g of a 25% by weight aqueous solution Ammonia solution was added and the mixture was stirred at 25 ° C. for 15 min, a light blue suspension being obtained (suspension B). Then the suspension B was stirred into the solution A at 90 ° C. and the resulting suspension was stirred at 80 ° C. for 3 h.

The aqueous suspension medium of the resulting aqueous suspension (Sus after cooling to 25 ° C, pension C) had a pH (glass electrode) of 5.3 on. The suspension C was at an inlet temperature of 310 ° C and spray dried at an outlet temperature of 110 ° C.

The green powder obtained was calcined in air, in one first step within 24 h continuously from 25 ° C to 300 ° C and in a subsequent second step continuously within 3 h heated from 300 to 780 ° C, and in a third step the temperature Was held at 780 ° C for 1 h. The calcination was carried out in a rotary kiln with a usable volume of 1 l, with 60 g each gear spray powder was used and an air flow of 50N 11h was set.

The resulting powder had a brown color and a specific surface area according to DIN66131 of 0.3 m ² / g and the composition Cu ₁₂ Mo ₆ W ₆ O _42-48 . In the SEM examination, the powder showed crystalline particles with a number-average grain size diameter of about 8 µm. Using CU-Kα radiation (Siemens diffractometer D-5000, 40 kV, 30 mA, with automatic and counter tube aperture and Peltier detector), the crystalline powder showed a powder X-ray diagram, which also shows a superposition of the tungsten fingerprint showed the HT-Cu molybdate fingerprint, ie it had a two-phase structure. According to the line intensities, the two structure types were approximately in the frequency ratio 60 (tungsten structure): 40 (HT-Cu-Molyb dat type).

The HT-Cu molybdate structure type can be determined by the following X-ray diffraction diagram, recorded on a crystalline powder of the composition CuMo _0.9 W _0.1 O _3.5-4 using CU-Kα radiation (Siemens diffractometer D500, 48 kV, 30 mA, with automatic divergence, scattering beam and counter tube diaphragm and Peltier detector) and reproduced in the form of network plane distances d [Å] independent of the wavelength of the X-rays used, as well as the associated diffraction line with the highest intensity (amplitude) relative intensities (%) of the different diffraction lines (arranged according to decreasing intensity) characterized:

The inaccuracy of specifying the network level spacing d amounts to d values <2.9 Å essentially to ± 0.3 Å and for d values <2.9 Å in the we considerably to ± 0.2 Å (the low-intensity lines may also include minor contaminants (lines receding).

3) Production of multimetal oxide compositions MIII1, MIII2 and MIII3 Example MIII1

A mixture of the correspondingly ground multimetal oxide MI1 (Mo ₁₂ V _3.47 W _1.39 O _47.11 ) and the powder was ground to a number-average grain size diameter of 1 to 3 μm using a centrifugal mill from Retsch, DE Multimetal oxide MII1 (Cu ₁₂ Mo ₁₂ O ₄₈ ) used. MII1 was stirred so much into the ground MI1 that the molar ratio of the aforementioned stoichiometric units in the resulting mixed powder was 6.5 (MI1): 1 (MII1). An intimate mixing of the two powders was achieved by mixing in an intensive mixer from Gustav Eirich, Hardheim, DE (type RO2, MPM system). Using a 10 l volume, rotating plate with 64 revolutions per minute and a "Star" whirling tool. which rotated counter to the plate at 900 revolutions per minute, 600 g of mixture were mixed for 15 minutes.

The resulting two-phase active mass was:

[Mo ₁₂ V _3.47 W _1.39 O _47.11 ] _6.5 [Cu ₁₂ Mo12O ₄₈ ] corresponds to Mo ₁₂ V ₃ W _1.2 Cu _1.6 O _47.23

Example MIII2

Like MIII1, but instead of the multimetal oxide MII1, the multimetal oxide became MII2 used.

The resulting active mass was:

[Mo ₁₂ V _3.47 W _1.39 O _47.11 ] _6.5 [Cu ₁₂ Mo ₆ W ₆ O _42-48 ].

Example MIII3

A multimetal oxide was made directly from the metal salt solutions and not from two separate multimetal oxides:
127 g of copper (II) acetate monohydrate were dissolved in solution I in 2,700 g of water. 860 g of ammonium heptamolybdate tetrahydrate, 143 g of ammonium metavanadate and 126 g of ammonium paratungstate heptahydrate were successively dissolved in solution II in 5,500 g of water at 95 ° C. Solution I was then stirred into solution II at once and the aqueous mixture was spray-dried at an exit temperature of 110.degree. Then the spray powder per kg powder was kneaded with 0.15 kg water. The plasticine was calcined in a forced air oven charged with an oxygen / nitrogen mixture. The oxygen content was adjusted so that there was an O ₂ content of 1.5% by volume at the outlet of the circulating air oven. In the course of the calcination, the modeling clay was first heated to 300 ° C. at a rate of 10 K / min and then kept at this temperature for 6 hours. The mixture was then heated to 400 ° C. at a rate of 10 K / min and this temperature was maintained for a further hour. To adjust the ammonia content of the calcining atmosphere, the furnace loading O (g catalyst precursor per l internal volume of the circulating air oven), the input volume flow ES (Nl / h) of the oxygen / nitrogen / mixture and the residence time VZ (sec.) Of the oxygen / nitrogen feed were determined (Ratio of internal volume of the circulating air oven and volume flow of the supplied oxygen / nitrogen mixture) selected as listed below. The convection oven used had an internal volume of 3 l.
O: 250 g / l
VZ: 135 sec. And
ES: 80 Nl / h.

The resulting catalytically active material is based on the following stoichiometry:

Mo ₁₂ V ₃ W _1.2 Cu _1.6 O _x .

Claims (11)

1. Use of multimetal oxides of the general formula I
Mo _12-abc V _a M ¹ _b M ² _c O _x (I)
in which the variables have the following meaning:
M ¹ = W and / or Nb,
M ² = Ti, Zr, Hf, Ta, Cr, Mn, Re, Ag, Cu, Si and / or Ge,
a = 0.1 to 6,
b = 0 to 6,
c = 0 to 6,
with the proviso that a + b + c = 0.1 to 6 and
x = a number which is determined by the valency and frequency of the elements in I other than oxygen,
which are characterized in that their atomic spatial arrangement using CU-Kα radiation (λ = 1.54178 Å) causes a powder X-ray diffraction spectrum (the intensity A of the diffracted X-ray radiation plotted as a function of twice the diffraction angle (2θ)), that in the 2θ range from 5 ° to 50 ° contains at least the following characteristic diffraction lines A ³ , A ⁵ , A ⁹ and A ¹⁰ , but preferably at most the following diffraction lines A ¹ to A ¹⁰ :
as combustion moderators for gas-generating mixtures. 2. Use according to claim 1, wherein at least one multimetal oxide I according to claim 1 as a mixture with at least one multimetal oxide of the general formula II
M ³ ₁₂ Cu _d H _e O _y (II)
With
M ³ = Mo, W, V, Nb and / or Ta,
d = 4 to 30,
e = 0 to 20 and
y = a number which is determined by the valency and frequency of the elements in II other than oxygen,
is used. 3. Use of at least two-phase multimetal oxide compositions of the general formula III
[A] _p [B] _q (III),
in which the variables have the following meaning:
A = (Mo _12-abc V _a M ¹ _b M ² _c O _x ). (12 / (12-abc)) (active phase),
B = M ³ ₁₂ Cu _d H _e O _y (promoter phase),
M ¹ = W and / or Nb,
M ² = Ti, Zr, Hf, Ta, Cr, Si and / or Ge,
a = 0.1 to 6,
b = 0 to 6,
c = 0 to 6,
with the proviso that a + b + c = 0.1 to 6,
x = a number which is determined by the valency and frequency of the elements in A other than oxygen,
M ³ = Mo, W, V, Nb and / or Ta,
d = 4 to 30,
e = 0 to 20,
y = a number which is determined by the valency and frequency of the elements in B other than oxygen,
p, q = non-zero numbers whose ratio p / q is 200: 1 to 1: 100,
that the portion [A] in the form of three-dimensionally extended areas A of the chemical composition which are delimited from their local environment on account of their chemical composition which is different from their local environment
Mo _12-abc V _a M ¹ _b M ² _c O _x
and the portion [B] in the form of three-dimensionally extended regions B of the chemical composition which are delimited from their local environment on account of their chemical composition which is different from their local environment
M ³ ₁₂ Cu _d H _e O _y
included, the areas A, B are distributed relative to each other as in a mixture of fine-particle A and fine-particle B and the atomic space arrangement of the areas A using CU-Kα radiation (λ = 1.54178 Å) a powder - X-ray diffraction spectrum (the intensity of the diffracted X-ray radiation plotted as a function of twice the diffraction angle (2θ)) causes that in the 2θ range from 5 ° to 50 ° min the following characteristic diffraction lines A ³ , A ⁵ , A ⁹ and A ¹⁰ , preferably however contains at most the following diffraction lines A ¹ to A ¹⁰ :
as combustion moderators for gas-generating mixtures. 4. Use according to one of claims 1 to 3, characterized in that that the gas-generating mixture in airbag systems or rocket propulsion sentences is used. 5. Burning moderator containing at least 5% by weight of at least one Multimetal oxide of the general formula I as claimed in claim 1 is defined and / or at least one mixture as claimed 2 is defined and / or at least one two-phase multimetal oxide mass of the general formula III as defined in claim 3 is. 6. A gas generating mixture comprising a nitrogen-rich fuel, which may contain an oxidizer, and 0.02 to 10 wt .-%, based on the gas-generating mixture, at least one combustion moderator, as defined in one of claims 1 to 3 or 5. 7. Gas-generating mixture according to claim 6, characterized in that the nitrogen-rich fuel nitroguanidine, triaminoguanidine nitrate, Diguanidinium 5,5'-azotetrazolate, 3-nitro-1,2,3-triazol-5-one or a Mixture of these is. 8. Gas-generating mixture according to claim 6, characterized in that the nitrogen-rich fuel ammonium nitrate in pure or phase-stable  form. 9. Use of a gas-generating mixture according to one of the claims 6 to 8 in airbag systems or rocket engines. 10. Airbag propellant comprising a gas-generating mixture according to one of the Claims 6 to 8. 11. rocket propellant, comprising a gas-generating mixture according to one of the Claims 6 to 8.