NO781508L - PROCEDURE AND CATALYST FOR DEHYDROGENATION OF ALKYLAROMATIC COMPOUNDS - Google Patents

Description

Process and catalyst for the dehydrogenation of alkylaromatic compounds

The currently commercially used methods for dehydrogenation, e.g. by converting ethylbenzene to styrene,

are affected by the disadvantage that they give low conversions, while oxy-dehydrogenation processes that give higher conversions are affected by the disadvantage that they give poor selectivities. The selectivity is of particular importance in this particular turnover as the starting materials for the production of styrene make up over 80% of the production costs for styrene. There is therefore continuous research into catalytic materials that are more effective in that they reduce side reactions to a minimum and improve the conversion yields.

A number of catalysts and catalyst systems have been described where different phosphates and pyrophosphates are used for the conversion of alkylaromatic compounds into derivatives with side-chain unsaturation. Thus, in US Patent No. 3923916, nickel pyrophosphate is claimed as a superior catalyst for the oxydehydrogenation of alkylaromatic compounds. US patent documents no. 3933932 and no. 3957897 describe the use of lanthanum, rare earth species and alkaline earth phosphates as oxydehydrogenation catalysts for alkylaromatic compounds. Catalyst mixtures containing arsenic, antimony, bismuth or cadmium. phosphates and the like have been shown to have an outstanding activity in the dehydrogenation reaction in the present method, however, so far this has not been described. Although according to US patent no. 3873633 a cobalt-bismuth-phosphorus-oxygen mixture can be used as a catalyst for the oxydehydrogenation of paraffinic hydrocarbons to monoolefins or diolefins, the use of this type of catalyst for the conversion of alkylaromatic compounds to derivatives with chain 1 has not yet been known.

The invention relates to a method by oxydehydrogenation of alkyl-substituted aromatic compounds to the corresponding alkenyl-substituted aromatic compounds, and catalyst materials for carrying out the method. The invention relates more specifically to the oxydehydrogenation of alkylaromatic compounds for the production of the corresponding derivatives with side chain unsaturation, where the alkylaromatic compound contains at least one alkyl group with 2-6 carbon atoms, and where the alkyl group is attached to only one aromatic ring. The aromatic compound can be a mononuclear aromatic compound or a dinuclear aromatic compound with a condensed ring or a corresponding nitrogen-containing heterocyclic aromatic compound.

The present method is characterized by the fact that a gas mixture of molecular oxygen, such as air, and the alkylaromatic compound in the presence or absence of a dilution agent, such as ^amP'carbondioxyd, nitrogen or an inert hydrocarbon, is passed over a catalyst at a temperature of 300-650°C, using a catalyst with a composition that can be represented by the empirical formula:

in which A denotes an alkali metal and/or thallium, M denotes one or more of the elements nickel, cobalt, copper, manganese, magnesium, zinc, calcium, niobium, tantalum, strontium or barium, ' M"*" denotes one or more of the elements iron, chromium, uranium, thorium, vanadium, titanium, lanthanum or the other rare earths, M denotes one or more of the elements tin, boron, lead, germanium, aluminium, tungsten or molybdenum, B denotes bismuth, tellurium, arsenic, antimony, cadmium or mixtures thereof, P denotes phosphorus, and a-y have the following values: ;a = 0 to 20,;b = 0 to 20,;c = 0 to 20,;d = 0 to 4,;e = 0.1 to 20 and;y = 8 to 16,;x denotes the number of oxygen atoms necessary to ;satisfy the yalene requirements of the other elements present, and the sum of b + c +e is greater than 1. It is preferred for the embodiment of the present invention method of using catalyst materials where ;a = 0 to 2,;b = 4 to 12,;c =0.2 to 4,;d = 0 to 2, e = 0.5 to 5 and ;y = 10 to -14 .;Invent nelsen also relates to a catalyst material which is characterized by the fact that it can be represented by the empirical formula: A M, M1 M11 ,B PO, ;abcdeyx;in which A, M, M"*", M^~^~, B and P have the same meanings as stated above, and where a-y have the following values,

a = 0 to 5,

b = 4 to 20,

c = 0.1 to 10,.

d = 0 to 4,

e = 0.1 to 12 and y = 8 to 16,

x denotes the number of oxygen atoms necessary to satisfy the valence requirements of the other elements present, and the sum of 2b + 3 (c + e) is greater than 9 and less than 3y.

For a preferred catalyst material according to the invention is

a = 0 to 1, b = 4 to 12,

c = 0.1 to 4,

d = 0 to 2,

e = 0.1 to 4 and

the sum of 2b + 3 (c + e) is greater than 9 and less than 3y.

The catalysts according to the invention are surprisingly good dehydrogenation catalysts. Thus, by dehydrogenation of ethylbenzene to styrene, conversions to styrene per throughput of 70% and selectivities of up to 90%.

The catalysts which can be used in carrying out the present method can be used alone or on a carrier material. Suitable carrier materials include silicon dioxide, alundum, titanium dioxide or mullite, and especially carrier materials of the phosphate type, such as zirconium phosphate, antimony phosphate, aluminum phosphate or especially boron phosphate. The carrier material can generally be used in an amount of less than 95% by weight of the final catalyst's composition, and the catalyst can be incorporated into the carrier material by coating, impregnation or co-precipitation.

The catalysts can be prepared by co-precipitation or by other known methods. They are usually prepared by mixing an aqueous solution of the metal nitrates with an aqueous solution of ammonium dihydrogen phosphate, then drying the precipitate.

The catalysts can be calcined to obtain desired physical properties, such as friction resistance, optimal surface area and optimal particle size. It is generally preferred that the calcined catalyst is further heat-treated in the presence of oxygen at a temperature above 250°C, but below a temperature which is harmful to the catalyst.

Among dialkyl aromatic compounds which can be used as starting material for carrying out the present method, mention may be made of the monosubstituted aromatic compounds, such as e.g. ethylenebenzene, isopropylbenzene or sec.butylbenzene, disubstituted aromatic compounds, such as ethyltoluene, diethylbenzene or t-butylethylbenzene, trisubstituted aromatic compounds, such as the ethylxylenes, condensed ring aromatic compounds, such as ethylnaphthalene, methylethylnaphthalene or diethylnaphthalene,

or nitrogenous heterocyclic aromatic compounds, such as ethylpyridine, methylethylpyridine, ethylquinoline or ethylisoquinoline, etc.

Particularly preferred reactants for this reaction are ethylbenzene, which is easily converted to styrene, diethylbenzene, which is converted into mixtures of ethylstyrene and divinylbenzene, and ethylpyridine and methylethylpyridine, which are converted into, respectively, vinylpyridine and methylvinylpyridine.

The reaction can be carried out in a fixed bed or a fluidized bed reactor at temperatures as low as 300°C, although optimum temperatures for the dehydrogenation of the alkyl side chains are 400-600°C, and there is no appreciable advantage in using working temperatures such as lies significantly above 650°C.

The pressure at which the present method is usually carried out is approximately atmospheric pressure, although pressures from slightly below atmospheric pressure and up to more than 3 atmospheres can be used.

The apparent contact time used in the execution

of the present method, can be 0.1-50 seconds, and to achieve good selectivity and good yields, a contact time of 1-15 seconds is preferred.

The molar ratio between oxygen and alkylaromatic compound

which is supplied to the reactor, can vary from 0.5 to 4 mol of oxygen per mol alkylaromatic compound, but a preferred range is 0.5-1.5 mol oxygen per moles of aromatic compound. The oxygen used can be in the form of pure oxygen, although for the sake of simplicity it is preferred to use air.

Diluents, such as steam (water vapour), carbon dioxide, nitrogen, inert hydrocarbons or other inert gases, can also be used, and a diluent quantity of 0-20 parts by volume per volume part alkylaromatic compound is suitable.

In the examples below, the simplicity and the improvement obtained by the oxydehydrogenation process using catalysts according to the invention are described, compared to such a process using known catalysts.

Examples 1-2 6' are representative of the present invention, while comparative examples A-E are representative of known processes.

Catalyst production

Comparative example A

<Ni>2<P>2°7

168.5 g of nickel nitrate hexahydrate was dissolved in 500 em 3 of water,

and the acidity was adjusted to a pH of 6.4 with ammonia. 77.7 g of ammonium dihydrogen phosphate was dissolved in 250 cm 3 of water and the pH adjusted to 6.8 with ammonia. The solutions were mixed and stirred at room temperature: for 15 minutes after the pH had been adjusted to 6 with ammonia, after which the mixture was filtered. The light green precipitate obtained was filtered, dried at 110°C and heat treated for 3 hours at 290°C, for 3 hours at 427°C and for 2 hours at 550°C to obtain a light brown solid material

with a surface area of 14 m 2/g.

Comparative example B

<Mg>2<P>2<0>7

309.2 g of magnesium nitrate hexahydrate was dissolved in 60 cm 3 of water while heating. 138.2 g of ammonium dihydrogen phosphate were dissolved in 100 cm 3 of water while heating. The solutions were mixed and stirred while heating until a white, thick paste had formed. The paste was dried at 110°C and heat treated at 290°C for 3 hours, at 427°C for 3 hours and at 550°C for 16 hours in air under ice to obtain a white solid material with a surface area of 21.8 . m2/g.

Comparative example C

<La>4(P2°7)3

130 g of lanthanum nitrate hexahydrate ("Trona" code 548) was dissolved

3 '3

in 31.5 cm of nitric acid and diluted to 250 cm with water. 57.1 g of ammonium dihydrogen phosphate was dissolved in 250 cm 3 of water and acidified to a pH of approx. 1 with 2 5 cm<3>nitric acid. When the solutions were mixed with stirring, an opalescent sheen appeared. After stirring for 22 hours under heating, a milky white precipitate was formed. When heated to boiling, the gel thickened. The gel was filtered, dried at 110°C and heat treated for 3 hours at 290°C, for 3 hours at 427°C and for 16 hours at 550°C in air under ice to obtain a white solid material with a surface area a<y >17 m 2/g.

Comparative example D

<C>°7<Fe>3<P>l2°41.5

121.2 g of trivalent iron nitrate nonahydrate and 203.8 g of cobalt nitrate hexahydrate were dissolved in 10 ml of water under heating. 138 g of ammonium dihydrogen phosphate were dissolved in 100 ml of water while heating. The solutions were mixed and stirred while heating until a thick paste was formed. The paste was dried at 110°C

and then heat-treated for 3 hours at 290°C, for 3 hours at 427°C and for 3 hours at 550°C in air, and a blue solid material with a surface area of 0.8 m 2 /g was obtained. .

Comparative example E

<Co>2<P>2°7

349.1 g of cobalt nitrate hexahydrate was dissolved in 20 cm 3 of water below

-heating. 138 g of ammonium dihydrogen phosphate were dissolved in 100 cm<3>

water during heating. The solutions were mixed and stirred while heating until a thick violet paste was formed. The paste was dried at 110°C and heat treated for 3 hours at 290°C, for 3 hours at 427°C and 16 hours at 550°C, obtaining a blue solid material with a surface area of 12.2 m<2 >/g.

Example 1

<Bi>8<P>12°42

194 g bismuth nitrate pentahydrate, 5 cm 3 concentrated nitric acid and 45 cm 3 water bee heated to 75°C with stirring..

69 g of ammonium dihydrogen phosphate were added to 50 cm 3 of water heated to 75°C. The two solutions were mixed and then stirred and heated until a white paste was formed. The pasta was

dried at 110°C, and heat treated for 5 hours at 290°C, for 3 hours at 427°C and for 3 hours at 550°C in air. A white solid was formed with a surface area of 0.3 m 2 /g.

Example 2

25%BigP12042- 75%BP04

19.4 g of bismuth nitrate pentahydrate was dissolved in 1 cm 3 of concentrated nitric acid and 9 cm 3 of water under heating. 6.9 g of ammonium dihydrogen phosphate was dissolved in 25 cm 3 of water. The solutions were combined and 40.4 g of boron phosphate was added. The boron phosphate powder (-200 mesh) was made by mixing 121 g of 85% H3PO4 with 62 g of H^BO^/heating for 5 hours at 40°C, drying the resulting paste at 110°C and calcining■in air for 8 hours at 300°C. After the addition of BP04, the paste was dried at 110°C and heat treated as in Example 1. A white, solid material was formed with a surface area of 17 m<2>/g.

Example 3

- Cu, cBiPc-0,t-c.- 95%BP04

1.5515.5.

b8u5t%-anig oEl Ht a3vbP0odre4 fsvotesid flaléå tprutinlivg lber aav kbell1øe 7p0 fsrcdmeems3 tstaiilzelloet rte rfrop Ha 3Ba45 l0k3 og hi Ho3^lB-5vO0 ^ acnmnav b3 las5ne0 kdci.mng3

and subsequent addition of H 3 PO 4 . After further distillation to remove water, the resulting gel was dried and calcined at 260°C. 1.6 g of copper? :t (II)-nitrate hexahydrate and 1.75 bismuth nitrate-3 3 pentahydrate were dissolved in 2.5 cm of nitric acid and 22.3 cm of water and added to 25 g of BP04 powder. The paste was dried at 110°C and heat treated as in Example 1". The light blue solid material obtained had a surface area of 63 m 2 /g.

Example 4

<Fe>10<Bi>0.7<P>12°46

138 g of ammonium dihydrogen phosphate were dissolved in 100 cm 3 with stirring. 404 g of trivalent iron nitrate nonahydrate and 35.1 g of bismuth nitrate pentahydrate were added in the indicated order to 10 cm<3> of water and heated. The obtained nitrate solution was added to the phosphate solution. A slurry was formed which was heated with stirring to remove water and then dried and calcined as in Example 1. The resulting light brown solid had a surface area of 3.8 m 2 /g.

Example 5

<C>°10<Bi>0.7<P>12°41

138 g of ammonium dihydrogen phosphate, 291.1 g of cobalt nitrate hexahydrate and 35.1 g of bismuth nitrate pentahydrate were dissolved and brought together as in Example 4. After a heat treatment as described in Example 1, a blue solid material with a surface area of 5.4 m was formed 2/g.

Example 6

C°7F<e>3Bi0.7<P>12°43

A nitrate solution was prepared from 203.8 g of cobalt nitrate hexahydrate, 1.21.2 g of trivalent iron nitrate nonahydrate and 35.1 g of bismuth nitrate pentahydrate together with 10 cm of water and added to 138 g of an ammonium dihydrogen phosphate solution as described in Example 4. After a heat treatment as described in Example 1 a blue, solid material with a surface area of 2 was obtained

of 7, 7 m/g.

Example 7

50% Go7Fe3Bi1P12043-50% BP04

A nitrate solution was prepared from 85 g of cobalt nitrate hexahydrate, 50.5 g of trivalent iron nitrate nonahydrate and 20.2 g of bismuth nitrate pentahydrate together with 5 cm 3 of water. It was added to 57.5 g of an ammonium dihydrogen phosphate solution in 100 cm<3> of water to which 53 g of boron phosphate prepared as described in example .2 was added. After stirring and heating, the slurry was dried and calcined as described in example 1. The blue solid material obtained had a surface area of 11.9 m 2 /g.

Example 8

<C>°9.5<Fe>0.5<BiP>l2°42

A nitrate solution was prepared from 276.5 g of cobalt nitrate hexahydrate, 20.2 g of trivalent iron nitrate nonahydrate and 48.5 g of bismuth nitrate pentahydrate. It was added to a solution of 138 g of ammonium dihydrogen phosphate in 100 cm 3 of water, dried and heat-treated as described in Example 1. The blue solid material obtained had a surface area of 12.6 m 2 /g.

Example 9

Mg9FeBiP12<04>2

A nitrate solution was prepared from 115.4 g of magnesium nitrate hexahydrate, 20.2 g of trivalent ferric nitrate nonahydrate and 24.3 g of bismuth nitrate pentahydrate. It was added to a solution of 69 g of ammonium dihydrogen phosphate in 50 cm 3 of water and dried and heat-treated as described in example 1. The cream-coloured solid material obtained had a surface area of 12 m 2 /g.

Example 10

Co9CrBiP12042

A nitrate solution was prepared from 131 g of cobalt nitrate hexahydrate, 20 g of chromium (III) nitrate nonahydrate, 24.3 g of bismuth nitrate pentahydrate and 5 cm 3 of water. It was added to a solution of 69 g of ammonium dihydrogen phosphate in 50 cm 3 of water, dried and heat-treated as described in Example 1. The blue solid material obtained had a surface area of 14.3 m 2 /g.

Example 11

<C>o7<La>1/5<Bi>2<P>12<0>42

A nitrate solution was made from 101.9 g of cobalt nitrate hexahydrate, 32.8 g of lanthanum nitrate hexahydrate, 48.5 g of bismuth nitrate pentahydrate and 7 cm 3 of concentrated nitric acid. It was added to a solution of 69 g of ammonium dihydrogen phosphate in 50 cm 3 of water, dried and heat-treated as described in example 1, with the difference that the treatment at 550 C was extended to 16 hours. The blue solid material obtained had a surface area of 19.4 m 2 /g.

Example 12

<C>o8L<a>05<Bi>2<P>l2<O>42

A nitrate solution was prepared from 116.4 g of cobalt nitrate hexahydrate, 10.9 g of lanthanum nitrate hexahydrate, 48.5 g of bismuth nitrate-3 3 pentahydrate and 3 cm of concentrated nitric acid with 10 cm of water. It was added to 69 g of ammonium dihydrogen phosphate dissolved in 50 cm<3> of water, and then dried and heat treated as in example .11. The blue solid material obtained had a surface area of 7.7 m 2 /g.

Example 13

Co9L<a>l,0<Bi>l<P>12°42

A nitrate solution was prepared from 131 g of cobalt nitrate hexahydrate, 21.7 g of lanthanum nitrate hexahydrate and 24.3 g of bismuth nitrate pentahydrate with 10 cm 3 of water. It was added to 69 g of ammonium dihydrogen phosphate dissolved in 50 cm 3 of water. The slurry was dried. and heat-treated as described in example 1. The blue solid material obtained had a surface area of 10.5 m 2 /g.

Example 14

<K>0.01C°9L<a>i<BiP>12°42

A nitrate solution was prepared as described in Example 13. A 10 cm 3 solution of potassium acetate (0.5 g/100 cm 3 ) was added to the mixed nitrates, and the nitrate solution was added to an ammonium dihydrogen phosphate solution as described in Example 13. The slurry was dried and heat-treated as described in Example 11. The blue solid material obtained had a surface area of 19.0 m<2>/g.

Example 15

Co7Zn2La1BiP12<0>42

A nitrate solution was prepared from 101.9 g cobalt nitrate hexahydrate, 29.8 g zinc nitrate hexahydrate, 21.7 g lanthanum nitrate hexahydrate and 24.3 g bismuth nitrate pentahydrate in 5 cm 3 of water. It was added to a solution of 69 g of ammonium dihydrogen phosphate in 50 cm 3 of water. After stirring and heating, the slurry was dried and heat-treated as described in example 11. The obtained blue,

solid material had a surface area of 8.6 m 2 /g.

Example 16

Co9CeBiP13045

27.4 g of cerium ammonium nitrate was dissolved in 5 cm 3 of concentrated nitric acid and 100 cm<3> of water. 24.3 g of bismuth nitrate pentahydrate and .. 131 g of cobalt nitrate hexahydrate were added to the cerium solution and dissolved. The solution obtained was added to a solution of 7 4.8 g of ammonium dihydrogen phosphate in 50 cm 3 of water. The slurry obtained was dried and heat treated as described in example 1. The solid material obtained had a surface-2

area of 10.3 m /g.

Example' 17

Mg9LaiBiP12042

A nitrate solution was prepared from 115.4 g of magnesium nitrate hexahydrate, 21.7 g of lanthanum nitrate hexahydrate and 24.3 g of bismuth nitrate pentahydrate in 10 cm 3 of water. It was added to a solution of 69 g of ammonium dihydrogen phosphate in 50 cm 3 of water. After stirring and heating, the slurry was dried and heat treated as described in example 1. White, solid material was obtained

had a surface area of 27 m<2>/g.

Example 18

Co"Di"BiP O

16.5 g "Didymium" oxide, i.e. mixed earths from Trona Corp. Code 4 22, was dissolved in 25 cm 3 of concentrated nitric acid.

. ' became/

24.J9 bismuth nitrate pentahydrate added to the "didymium" solution which was then added to a solution of 69 g of ammonium dihydrogen phosphate in 50 cm 3 of water. A solution of 131 g of cobalt nitrate hexahydrate in 10 cm 3 of water was then added. The slurry was dried and heat treated as described in example 1. The blue solid material obtained had a surface area of 15.4 m<2>/g.

Example 19

Co Fe TeP O

U 9 1 12 42.5

8 g of teilurium dibxyd were dissolved in 10 cm 3 of nitric acid under heating. The solution was added to a nitrate solution consisting of 131 g of cobalt nitrate hexahydrate and 20.2 g of trivalent iron nitrate nonahydrate and 5 cm 3 of water. The nitrate solution was added to a solution of 69 g of ammonium dihydrogen phosphate in 50 cm<3> of water. The slurry was dried at 110°C and heat treated as described in example 1, the final step at 550°C being carried out in the stainless steel reactor. The blue solid material obtained had a surface area of 59.9 m 2 /g.

Example 20

<C>°10<Sb>l<P>12°41.5 3 3 A slurry of 14.6 g of Sb 2 O 3 in 10 cm of glacial acetic acid and 10 cm of water was added to a solution of 69 g of ammonium dihydrogen phosphate in 50 cm 3 of water. A solution of 145.5 coboite nitrate hexahydrate in 10 cm 3 of water was added. After heating and stirring, the slurry was dried and heat treated as described in example 1.

Example 21

<C0>10<AS>1<P>12<0>41.5

3 3

A slurry of 9.9 g of As 2 O 2 in 10 cm of glacial acetic acid and 40 cm of water was added to a solution of 69 g of ammonium dihydrogen phosphate in 50 cm 3 of water. The remainder of the preparation was the same as described in Example 20.

Example 22

Co, nca~ p1o0

10 2 12 x

145.5 cobalt nitrate hexahydrate and 30.8 cadmium nitrate tetrahydrate were dissolved in 10 cm 3 of water. This solution was added to a solution of 69 g of ammonium dihydrogen phosphate in 80 cm 3 of water. The slurry obtained was dried and heat treated as described in example 1.

Example 23

COgBaFeBiP12<0>4<2>

A nitrate solution was prepared from 116.4 g cobalt nitrate hexahydrate, 24.3 g bismuth nitrate pentahydrate, 20.2 g trivalent iron-3

nitrate nonahydrate and 50 cm water. 15.8 g of barium hydroxydoctahydrate bee acidified with a 10% solution of concentrated nitric acid in water until a pH' of. 1.5 and then added to the nitrate. The slurry obtained was added to a solution of 69 g ... 3 ammonium dihydrogen phosphate in 50 cm of water. The slurry was dried

and heat-treated as described in example 1 to obtain a solid material with a surface area of 10.6 m 2 /g.

Oak sample 24

Co9CeBiP12045

The same catalyst as described in Example 16 was regenerated by passing air over the catalyst at the reaction temperature.

Example 2 5

MggLaBiP12<0>42

The same catalyst described in Example 17,

was regenerated by passing air over the catalyst at the reaction temperature.

Example 26

K0,lCO9CriBilP12°4<2>

The catalyst was prepared in the same way as the catalyst according to example 10, but with the difference that 0.49 g of potassium acetate was added to the nitrate solution. The surface area was 15.2 m 2 /g.

The number of oxygen atoms in the catalysts according to examples 1-26 was estimated. However, the number of oxygen atoms can in reality vary from approx. 30 to 60, depending on the reaction conditions.

The above catalyst materials were used for the oxy-hydrogenation of ethylbenzene to styrene, diethylbenzene to divinylbenzene and methylethylpyridine to methylvinylpyridine in a fixed bed reactor comprising a stainless steel tube with an outer diameter of 1.27 cm and a catalyst volume capacity of 15

3

cm

A reactant mixture of air, aromatic compound and nitrogen was pre-mixed and introduced into the reactor in a molar ratio of 5:1:2. The reactor was kept at a temperature of 530-532°C and at atmospheric pressure. The fluid volume rate per

hour for the introduction of the aromatic compound over the catalyst was 0.23 h and the contact time 3.3 seconds. The catalyst particle size used was 20-35 mesh. The conversion to the desired alkenylaromatic compound per review and the selectivity for the sales as reproduced in tables l-1 3 was .

■ calculated-in the following way:

Claims (18)

1. Process for the dehydrogenation of an alkylaromatic compound to the corresponding alkenylaromatic compound, where the alkylaromatic compound contains at least one alkyl group with 2-6 carbon atoms which is bound to a single aromatic ring, and where the aromatic group consists of mononuclear aromatic bonds, dinuclear aromatic compounds with a condensed ring or the corresponding nitrogen-containing heterocyclic-aromatic compounds, characterized in that a gaseous mixture of the alkyl aromatic compound, molecular oxygen and optionally a dilution gas is passed over a catalyst at a temperature of 300-650°C, as the a catalyst with a composition that can be represented by the following empirical formula is used: in which A denotes an alkali metal and/or thallium, M denotes one or more of the elements nickel, cobalt, copper, manganese, magnesium, zinc, calcium, niobium, tantalum, strontium or barium, M" <*> " denotes one or more of the elements iron, chromium, uranium, thorium, vanadium, titanium, lanthanum or the other rare earths, M" <*> "" <*> " denotes one or more of the elements tin , boron, lead, germanium, aluminium, tungsten or molybdenum, B denotes bismuth, tellurium, arsenic, antimony, cadmium or combinations thereof, P denotes phosphorus, and a-y have the following values: a = 0 - 20, b = 0 - 20, c = 0 - 20, d = 0 - 4, e = 0.1 - 20, y 8 - 16, x denotes the number of oxygen atoms that are necessary to satisfy the valence requirement of the others present elements, and the sum of b + c + e is greater than 1. 2. Method according to claim 1, characterized in that a catalyst is used in which a-y have the following values: a = 0 - 2, b = 4 - 12, c = 0 , 2 - 4 , d = 0 - 2, e =0.5 - 5 and y = 10 - 14. 3. Method according to claim 1, characterized in that ethylbenzene is converted to styrene. 4. Method according to claim 1, characterized in that diethylbenzene is converted to divinylbenzene. 5. Method according to claim 1, characterized in that ethyltoluene is converted to vinyltoluene. 6. Process according to claim 1, characterized in that methylethylpyridine is converted to methylvinylpyridine. 7. Method according to claim 1, characterized in that ethylpyridine is converted to vinylpyridine. 8. Method according to claim 1, characterized in that oxygen and alkylaromatic compound are added in a molar ratio of 0.5-4. 9. Method according to claim 8, characterized in that a reaction temperature of 400-600°C is used. 10. Method according to claim 8 or 9, characterized in that an apparent contact time of 1-15 seconds is used. 11. Method according to claims 8-10, characterized in that a catalyst material is used in which M denotes cobalt, M"<1>" lanthanum and B bismuth. 12. Method according to claims 8-10, characterized in that a catalyst material is used in which M denotes cobalt, M <1> iron and B tellurium. 13. Method according to claims 8-10, characterized in that a catalyst material is used in which M denotes magnesium, M" <*> " lanthanum and B bismuth. 14. Catalyst material for carrying out the method according to claim 1, characterized in that it can be represented by the empirical formula: in which A denotes an alkali metal and/or thallium, M denotes one or more of the elements nickel, cobalt, copper, manganese, magnesium, zinc, calcium, niobium, tantalum, strontium or barium, M" <*> " denotes one or more of the elements. iron, chromium, uranium, thorium, vanadium, titanium, lanthanum or the other rare earths, M denotes one or more of the elements tin, boron, lead, germanium, aluminium, tungsten or molybdenum, B denotes one or more of the elements bismuth, tellurium, antimony, arsenic or cadmium, P denotes phosphorus, and where a-y have the following values: a = 0 - 5, b = 4 - 20, c = 0.1 - 10, d = 0 - 4, e = 0.1 - 12, y = 8 - 16 and x denotes the number of oxygen atoms that are necessary to satisfy the valence needs of the other elements present, and the sum of 2b + 3.(c + e) is greater than 9 and less than 3y. 15. Catalyst material according to claim 14, characterized by a = 0 - 1, b = 4 - 12, c = 0.1 - 4, d = 0 - 2, e = 0.1 - 4 and the sum of 2b + 3 (c + e) is greater than 9 and less than 3y. 16. Catalyst material according to claim 14, characterized in that M denotes cobalt, M" <*> " lanthanum and B bismuth. 17. Catalyst material according to claim 14, characterized in that M denotes cobalt, M1 iron and B tellurium. 18. Catalyst material according to claim 14, characterized by M denotes magnesium, M lanthanum and B bismuth.