CS199528B2 - Method for the oxydehydrogenation of alkylaromatic compounds - Google Patents

Abstract

This invention relates to an improved process for the dehydrogenation of alkyl-substituted aromatic compounds to the corresponding, alkenyl-substituted aromatics in the presence of oxygen and in the presence of an improved metal phosphate catalyst composition.

Description

The present invention relates to an improved process for the dehydrogenation of alkyl-substituted aromatic compounds to the corresponding alkenyl-substituted aromatic compounds in the presence of oxygen and in the presence of a metal phosphate catalyst composition.

The lack of current dehydrogen-. In a process such as the conversion of ethylbenzene to styrene, the degree of conversion is low, while the lack of oxydehydrogenation with a higher degree of conversion is poor selectivity. In this reaction it is. selectivity is particularly important since the starting materials for the production of styrene represent 80% of its production cost. Therefore, catalyst compositions that are more efficient and that minimize side reactions and improve the degree of conversion are still sought.

Numerous catalysts and catalyst compositions have been developed using various phosphates and pyrophosphates to convert alkylaromatic compounds to derivatives with unsaturated side chains. For example, U.S. Pat. No. 3,923,916 protects nickel pyrophosphate as a more effective catalyst for the oxydehydrogenation of alkylaromatic compounds. No. 9,933,932 and U.S. Pat

957 '897 protects the use of lanthanum, rare earth and alkaline earth metal phosphates as oxyide hydrogenation catalysts for alkylaromatic compounds. However, catalyst compositions containing arsenic, antimony, bismuth or cadmium phosphates having excellent dehydrogenation activity according to the invention have not been described and protected hitherto. Although US 3,773,633 uses cobalt, bismuth, phosphorus and oxygen based systems as catalyst compositions for the oxydehydrogenation of paraffinic hydrocarbons to monoolefins or diolefins, the use of this type of catalyst to convert alkylaromatic compounds to derivatives with unsaturated side chains not yet known.

Thus, the present invention relates to a process for oxydehydrogenation of alkyl-substituted aromatic compounds to the corresponding -alkenyl-substituted aromatic compounds and to novel catalyst compositions for the process. In particular, the invention relates to a process for the oxydehydrogenation of alkylaromatic compounds to the corresponding unsaturated side-chain derivatives, wherein the aromatic compounds contain at least one alkyl group having 2 to 6 carbon atoms and wherein the alkyl groups are bonded only to arp199 5 28 math core. The aromatic compounds may be mononuclear compounds of a fused ring di-nuclear aromatic compound or the corresponding heterocyclic aromatic compounds containing nitrogen atoms.

In the process of the invention, a gaseous mixture of molecular oxygen, e.g. air, and alkyl-substituted aromatic compounds, optionally in the presence of a diluent such as steam, carbon dioxide, nitrogen or inert hydrocarbon, is passed through the catalyst composition at 300 to 650 ° C. consists of a combination of elements corresponding to formula I

AaMbM ^ M ^ BePyOx, (I) where is

And alkali metal or thallium,

M one or more elements selected from the group consisting of nickel, cobalt, copper, manganese, magnesium, zinc, calcium, niobium, tantalum, strontium or barium,

M ¹ one or more of iron, chromium, uranium, thorium, vanadium, titanium, lanthanum or other rare earth metal,

M ^for one or more elements selected from the group consisting of tin, boron, lead, germanium, aluminum, tungsten or molybdenum,

Bismuth, tellurium, arsenic, antimony, cadmium or a mixture thereof,

P phosphorus aa zero up to 20, b zero up to 20, c zero up to 20, d zero up to 4, e number 0,1 to 20, у number 8 to 16, xnumber of carbon atoms needed to saturate bonds of other and wherein the sum of b + c + e is greater than 1.

Catalyst compositions according to the invention are preferred in which a is zero to 2, b is 4 to 12, c is 0.2 to 4, d is 0 to 2, e is 0.5 to 5, and 6 is 10 to 14 .

The invention also encompasses catalyst compositions comprising a combination of elements corresponding to Formula I

АаМьМс'М ^ ВеРуОх, (I) where A, Μ, Μ ¹ , M ¹¹ , В, P are as defined above, and where a is zero to 5, b is 4 to 20, c is 0.1 to 10 , d zero to 4, e number 0,1 to 12, у number 8 to 16, x the number of carbon atoms required to saturate the bonds of the other elements present,. wherein the sum of 2b + -3 (c + e) is greater than 9 and less than 3y.

In a preferred catalyst composition, a is zero to 1, b is 4 to 12,.

c number 0.1 to 4, d zero to number 2, e number 0.1 to 4, wherein the sum of 2b + 3 (c + e) is greater than 9 and less than 3y.

The catalyst compositions of the invention are unexpectedly good oxydehydrogenation catalysts. For example, with dehydrogenation of ethylbenzene to styrene, the conversion to styrene in a single pass in the art is 70% and selectivity up to 90%.

The catalyst compositions can be used alone or on a carrier in the process of the invention. Suitable carriers include silica, Alundum, titanium dioxide and mullite, and especially phosphate type carriers such as zirconium phosphate, antimony, aluminum and especially boron phosphate. Generally, the support may be used in an amount of less than 95% by weight based on the weight of the finished catalyst composition, and the catalyst composition may be applied to the support by coating, impregnation and co-precipitation.

The catalysts of the invention can be prepared by coprecipitation or other methods known in the art. They are generally prepared by mixing aqueous solutions of metal nitrates with aqueous solutions of ammonium dihydrogen phosphate and drying the precipitate.

The catalyst composition can be calcined to achieve the desired physical properties, such as abrasion resistance, optimum surface area and particle size. In general, it is preferred that the calcined catalyst composition be further heat treated in the presence of oxygen at a temperature above 250 ° C, but at a temperature that would not be unfavorable to the catalyst composition.

Alkyllaromaitic compounds useful in the process of this invention include monosubstituted aromatic compounds such as ethylbenzene, isopropylbenzene, secondary butylbenzene; disubstituted aromatic compounds such as ethyltoluene, diethylbenzene, tert-butylethylbenzene; trisubstituted aromatic compounds such as ethylxylenes; condensed ring aromatic compounds such as ethylnaphthalene, methylethylnaphthalene, diethylnaphthalene; and nitrogen-containing heterocyclic aromatic compounds such as ethylpyridine, methylethylpyridine, ethylquinoline, ethylisoquinoline and the like. Particularly preferred reactive compounds in the process of the invention are ethylbenzene, which is readily transported.

The compound is styrene, diethylbenzene, which is converted into a mixture. ethylstyrene and divinylbenzene; ethylpyridine and methylethylpyridine being converted into vinylpyridine and methylvinylpyridine.

The reaction may be carried out in a solid layer or in a fluidized bed at a temperature of less than 300 ^° C, but the optimum temperature for dehydrogenation of the alkyl side chains is 400 to 600 ° C, but at temperatures above 650 ° C improvement.

The process according to the invention is generally carried out at normal atmospheric pressure, although it is also possible to work at a slightly lower pressure up to a pressure above 300 bar.

The apparent contact time in the process of the invention is 0.1 to 50 seconds and a contact time of 1 to 15 seconds is preferred for good selectivity and yield.

The molar ratio of oxygen to alkylaromatic compounds introduced into the reactor may be 0.5 to 4 moles of oxygen per mole of alkylaromatic compound, but a preferred amount is 0.5 to 1.5 moles of oxygen per mole of aromatic compound. Oxygen can be used in the form of pure oxygen, but the use of air is preferred for this purpose.

Diluents such as steam, carbon dioxide, nitrogen, inert hydrocarbons or other inert gases may also be used, and an amount of 0 to 20 parts by volume per part by volume of the alkylaromatic compound is suitable.

The following examples illustrate the advantages and 'improvements' achieved in the oxydehydrogenation process using the catalysts of the invention compared to those known in the art.

Specific embodiments Examples 1 to 26 relate to catalysts of the invention and Comparative Examples A to E relate to catalysts known in the art.

Preparation of catalysts

Comparative example A Ni ₂ P ₂ O _?

Nickel nitrate hexahydrate (168.5 grams) is dissolved in 500 ml of water and the acidity is adjusted to pH 6.4 with ammonia. Ammonium dihydrogen phosphate (77.7 g) was dissolved in 250 ml of water and adjusted to pH 6.8 with ammonia. The solutions were mixed and stirred at room temperature for 15 minutes, then the pH was adjusted to 6.0 with ammonia and filtered. The light green precipitate was filtered off, dried at 110 ° C and heat-treated for three hours at 290 ° C, for three hours at 427 ^° C and for two hours at 550 ° C, thereby to give a red-yellow solid having a surface area of 14 m 2 / g. ·>

Comparative example

Mg2P2O7

Magnesium nitrate hexahydrate (309.2 grams) was dissolved in 60 mL of water with heating. Ammonium dihydrogen phosphate (138.2 grams) was dissolved in 100 mL of water with heating. The solution was mixed and stirred with heating until a white thick paste was formed. · The paste was dried at 110 ° · C · heat-treated for three hours at 290 ^C. DEG C. for a period of three hours at · 427 · ^'I C and for 16 hours at 550 ® -teplotě C in air to give a white solid with a surface area of 21.8 m ² / g.

Comparative Example

1.34 ^ 207) 3

Dissolve lanthanum nitrate hexahydrate (Trona code 548) (130 g) in 31.5 ml nitric acid and dilute to 250 ml with water. Ammonium dihydrogen phosphate (57.1 grams) is dissolved in 250 ml of water and acidified to pH ~ 1 · 25 ml of nitric acid. The solutions are mixed with stirring to produce opalescence. Stir for 22. hours with heating to form a milky white precipitate. Heat to boil to thicken the gel. The gel is filtered off, dried at 110 DEG C., heat treated at 290 DEG C. for three hours, at 427 ^DEG C. for three hours, and at 550 DEG C. for 16 hours to air to give a white solid with a surface area of 17 m 2 / g.

Comparative Example D of

CoyFea ^P i2 ^C 4i. 5

· Ferric nitrate nonahydrate (121.2 grams) and cobalt nitrate hexahydrate (203.8 g) · are dissolved in 10 ml of water with heating, and ammonium dihydrogen phosphate (138.0 g) is dissolved in 100 ml of water with heating. They are mixed and stirred under heating until a thick paste is formed The paste is dried at 110 ° C, then heat-treated at 290 ° C for three hours, at 427 ° C C for three hours, and at 550 ^C for three hours in air to give a blue solid with a surface area of 0.8 m 2 / g.

Comparative Example

Co2P20y

Cobalt nitrate hexahydrate [349.1 g] was dissolved in 20 mL of water with heating. Dissolve ammonium dihydrogen phosphate (138.0 g) in 100 ml of water with heating. Roz199528

the streams are mixed and mixed with heating until a thick purple paste is formed. The paste is dried at 110 ° C and heat treated at 290 ° C for three hours, 427 ° C for three hours and at 550 ^° C for 16 hours to give a blue solid with a surface area of 12 ° C. , 2 m ² / g.

Example 1

_{Bi 12} O ₄₂ P

Bismuth nitrate pentahydrate (194 g), 5 ml nitric acid (concentrated) and 45 ml water are heated to 75 ° C with stirring, and ammonium dihydrogen phosphate (69.0 g) is added to 50 ml water and heated to 75 ° C. The two solutions are mixed, then mixed and heated until a white paste is formed.The paste is dried at 110 ° C, heat treated at 290 ^° C for five hours, at 427 ^° C for three hours. hours and at 550 Celsius for three hours in air The precipitate formed has a surface area of 0.3 m ² / g.

Example 2 _8% Bi P ₁₂ O ₄₂ to 75% BPO ₄

Bismuth nitrate pentahydrate (19.4 g) was dissolved in 1 ml nitric acid (concentrated) and 9 ml water while heating. Ammonium dihydrogen phosphate (6.9 g) was dissolved in 25 mL of water. The solutions were mixed and 40.4 boron phosphate was added. Boric phosphate (-200 mesh) is prepared by mixing 121 g of 85% phosphoric acid with 62 g of orthoboric acid of formula H ₃ BO ₃ , heating at 40 ° C for five hours, drying the resulting paste at 110 ° C and calcining at 110 ° C. air at 300 ^° C for eight hours. After addition of boron phosphate, the paste is dried at 110 ° C and heat treated as described in the example

1. The white solid has a surface area of 17 m ² / g.

Example 3 CutsBiPsOi ^% - 95% BPO ₄

The boron phosphate powder is prepared from 45 g of orthoboric acid and 50 ml of 85% phosphoric acid by refluxing orthoboric acid in Eastman sec-butanol (350 ml), distilling off 170 ml of an azeotropic alcohol / water mixture, and adding phosphoric acid. After further distillation to remove water, the resulting gel is dried and calcined at 260 ° C. Copper nitrate hexahydrate (1.60 g) and bismuth nitrate pentahydrate (1.75 g) were dissolved in 2.5 ml of nitric acid and 22.3 ml of water and 25 g of powdered boron phosphate was added. The paste is dried at 110 ^° C and heat treated as described in Example 1. The resulting light blue solid has a surface area of 63 m ² / g.

Example 4

ΕθιοΒίο, 7Ρ12θ46

Ammonium dihydrogen phosphate (138 g) was dissolved in 100 mL of water with heating. Add ferric nitrate nonahydrate (404 grams) and bismuth nitrate pentahydrate (35.1 g) respectively to 10 ml of water and heat. The resulting nitrate solution was added to the phosphate solution. The resulting suspension was heated with stirring to remove water, then dried and calcined as described in Example 1. A light red-yellow solid was obtained with a surface area of 3.8 m ² / g.

Example 5

СО ₁₀ В10.7Р1 ₂ О ₄ 1

Ammonium dihydrogen phosphate (138 g), cobalt nitrate hexahydrate (291.1 g) and bismuth nitrate pentahydrate (35.1 g) are dissolved and mixed as described in Example 4. Thereafter, heat treatment is performed as described in Example 1. A blue is obtained. solid with a surface area of 5.4 m ² / g.

Example 6

Co ₇ Fe ₃ Bi _{0 7} Fri ₂ O ₄₃

Prepare a nitrate solution from cobalt nitrate hexahydrate (203.8 g), ferric nitrate nonahydrate (121.2 g) and bismuth nitrate pentahydrate (35.1 g) and 10 ml of water and add to the ammonium dihydrogen phosphate solution (138.0 g) as described in Example 4. Heat treatment was carried out as described in Example 1. A blue solid having a surface area of 7.7 m ² / g was obtained.

Example 7% Co ₇ Fe ₃ Bi ₁ P ₁₂ 0 ₄ 3 - 50% BPO ₄

Prepare a nitrate solution from cobalt nitrate hexahydrate (85 g), ferric nitrate nonahydrate (50.5 g), and bismuth nitrate pentahydrate (20.2 g) and 5 ml of water. The nitrate solution is added to a solution of ammonium dihydrogen phosphate (57.5 g) in 100 ml of water to which 53 g of boron phosphate prepared as described in Example 2 are added. After stirring and heating, the suspension is dried and calcined as described in Example

I. The resulting blue solid has a surface

II, 9 m ² / g.

Example 8

СО ^ Рво.йВЬаРО ^ l

Prepare a nitrate solution from cobalt nitrate hexahydrate (276.5 g), ferric nitrate nonahydrate (20.2 g) and bismuth nitrate pentahydrate (48.5 g). The nitrate solution is added to a solution of ammonium dihydrogen phosphate (138 g) in 100 ml of water, dried and heat-treated as described in Example 1. A solid blue mass having a surface area of 12.6 m ² / g is formed.

Example 9

Mg ₉ FeBiPi ₂ O ₄₂

Prepare a nitrate solution from magnesium nitrate hexyhydrate (115.4 g), ferric nitrate nonahydrate (20.2 g) and bismuth nitrate pentahydrate (24.3 g). The mixture was added to a solution of ammonium dihydrogen phosphate (69 g) in 50 ml of water, dried and heat treated as described in Example 1. A cream colored solid was obtained with a surface area of 12.0 m ² / g.

Example 10

Co ₉ CrBlP ₁₂ O42

Prepare a nitrate solution from cobalt nitrate hexahydrate (131 g), chromium nitrate nonahydrate (20 g), bismuth nitrate pentahydrate (24.3 g) and 5 ml of water. The nitrate solution is added to a solution of ammonium dihydrogen phosphate (69 g ·) in 50 ml of water, dried and heat treated as described in Example 1. A blue solid with a surface area of 14.3 m ² / g is formed.

Example 1 a d 11

CoyLai 5BI2P12О42

Prepare a nitrate solution from cobalt nitrate hexahydrate (101.9 g), lanthanum nitrate hexahydrate (32.8 g), bismuth nitrate pentahydrate (48.5 g) and 7 ml of concentrated nitric acid. The solution was added to a solution of ammonium dihydrogen phosphate (69 g) in 50 mL of water, dried and heated as described in Example 1, except that the heat treatment at 550 ° C was prolonged for 16 hours. The resulting blue precipitate has a surface area of 19.4 m ² / g.

Example 1 a d 1 2

What to do _with La _0ili Bi ₂ P 12О42

Prepare a nitrate solution from cobalt nitrate hexa hydrate (116.4 g), lanthanum nitrate hexahydrate (10.9 g), bismuth nitrate pentahydrate (48.5 g) and 3 ml of concentrated nitric acid with 10 ml of water. The nitrate solution was added to ammonium dihydrogen phosphate (69 g) dissolved in 50 mL of water, dried and heat treated as described in Example 11. The resulting blue solid had a surface area of 7.7 m ² / g.

Example 1 a d 1 3

Co ₉ Like, oBiiP ₁₂ 0 ₄ 2

Prepare a nitrate solution from cobalt nitrate hexahydrate (131 g), lanthanum nitrate hexahydrate (217 g), and bismuth nitrate pentahydrate (24.3 g) and 10 ml of water. The solution was added to ammonium dihydrogen phosphate (69 g) dissolved in 50 mL of water. The suspension is dried and heat treated as described in Example 1. The resulting blue solid has a surface area of 10.5 m ² / g.

Example 14

K ₀ .oiCo ₉ La ₁ BiPi2042

A nitrate solution is prepared as described in Example 13. 10 ml of potassium acetate solution (0.5 g / 100 ml) is added to the nitrate mixture and the nitrate solution is added to the ammonium dihydrogen phosphate solution of Example 13. The suspension is dried and heat treated as described in Example 11. The resulting blue solid has a surface area of 19.0 m ² / g.

Example 15

CO7Zn ₂ LA ₁ BlP 12О42

Prepare a nitrate solution from cobalt nitrate hexahydrate (101.9 g), zinc nitrate hexahydrate (29.8 g), lanthanum nitrate hexahydrate (21.7 g) and bismuth nitrate pentahydrate (24.3 g) in 5 ml of water . The nitrate solution was added to a solution of ammonium dihydrogen phosphate (69 g) in 50 mL of water. After stirring and heating, the suspension is dried and heat treated as described in Example 11. The resulting solid blue mass has a surface

8.6 m ² / g.

Example 16

Co ₉ CeBiPi ₃ O45

Cerium ammonium nitrate (27.4 g) was dissolved in 5 µl of concentrated nitric acid and 100 ml of water. Bismuth nitrate pentahydrate (24.3 g) and cobalt nitrate hexahydrate (131 g) were added to the cerium solution and dissolved. The resulting solution was added. to a solution of ammonium dihydrogen phosphate (74.8 g) in 50 mL of water. The resulting suspension is dried and heat treated as described in Example 1. The solid formed has a surface area of 10.3 m ³ / g.

Example 17

Mg ₉ La1BiP 12O42

Prepare a nitrate solution from nitrate hexahydrate. magnesium (115.4 g), from lanthanum nitrate hexahydrate. (21.7 g) and bismuth nitrate pentahydrate (24.3 grams) in 10 ml of water The nitrate solution was added to a solution of ammonium dihydrogen phosphate (69 g) in 50 ml of water After stirring and heating, the suspension was dried and heat treated as described in Example 1. The resulting white solid had a surface area of 27 m 2 / g.

Example 18

Co-Di / BiP from Didymium Oxide, a mixed rare earth (16.5 g) (Trona Corp. Code · 422) is dissolved in 25 ml of concentrated nitric acid and bismuth nitrate pentahydrate (24.3 g) is added. (g) to a 'didymium' solution, which is then added to a solution of ammonium dihydrogen phosphate (69 g) in 50 ml of water, then a solution of cobalt nitrate hexahydrate (131 g) in 10 ml of water is added. Example 1. The resulting blue solid has a surface area of 15.4 m ² / g.

Example 19

Co9FeiTeP 12 ^ 1,2,5

Tellurium dioxide (8.0 g) was dissolved in 10 ml of nitric acid with heating. This solution is added to a nitrate solution consisting of cobalt nitrate hexahydrate (131 g) and ferric nitrate nonahydrate (20.2 g) and 5 ml of water. Nitrate solution. was added to a solution of ammonium dihydrogen phosphate (69 g) in 50 mL. water. The slurry was dried at ^{110: C} and heat treated as described in Example 1, with the 'final' heating at 550 ^C C carried out in a reactor -nerezavějící steel. The resulting blue solid has a surface area of 59.9 m 2 / g.

Example 1 a d 2 0

C0ioSbiPi2On.5

A suspension of antimony trioxide (14.6 g) in ml of glacial acetic acid and 10 ml of water is added - to ammonium dihydrogen phosphate (69.0 g) in 50 ml of water, and a solution of cobalt nitrate hexahydrate (145.5 g) in ml of water is added. After heating and stirring, the suspension is dried and heat treated as described in Example 1.

Example 21

C ₂ 041,5 ° 1oAS1P1

Suspension of 9.9 g of arsenic trioxide in 10 ml of ice. acetic acid and 40 ml of water were added to a solution of ammonium dihydrogen phosphate (69.0 g). in 50 ml of water. The procedure is as described in Example 20.

Example 22

Co10Cd2P i2 ^ x

Cobalt nitrate hexahydrate (145.5 g) and cadmium nitrate tetrahydrate (30.8 g) were dissolved in 10 ml of water. This solution was added to a solution of ammonium dihydrogen phosphate (69 g) in 80 mL of water. The resulting slurry was dried and heat treated as described in Example 1.

Example 2 3

Co ₈ BaFeBiP12O42

Prepare a nitrate solution from cobalt nitrate hexahydrate (116.4 g),. bismuth nitrate pentahydrate (24.3 g), ferric nitrate nonahydrate (20.2 g), and 50 ml of water. Barium hydroxide octahydrate (15.8 g) is acidified with a 10% concentrated acid solution. nitric acid in water to pH 1.5 and then added to the nitrate solution. The resulting suspension was added to a solution of ammonium dihydrogen phosphate (69 g) in 50 mL of water, dried and heat treated as described in Example 1 to give a solid with a surface area of 10.6 m 2 / g.

Example 24 ‘

Co ₉ CeBiP12O45>

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

Example 1 'and d ·' 2 5

Mg ₉ LaBiP i2O42

The same catalyst as in Example 17 was regenerated by passage. air through the catalyst at the reaction temperature.

Example 26

Ko.iCOcjCriBiiP 12Ο42

The catalyst composition was prepared in the same manner as the catalyst com199528 position of Example 10 except that the addition of kallumacetate (0.49 g) to the nitrate solution was 15.2 m ² / g.

The number of oxygen atoms is determined. in the catalyst compositions of Examples 1 to 26. However, the number of oxygen atoms may vary from 30 to 60, depending on the reaction conditions.

The above catalyst compositions are used in a process for the oxydehydrogenation of ethylbenzene to styrene, diethylbenzene to divinylbenzene and methylethylpyridine to methylvinylpyridine in a solid-layer reactor comprising a 12.7 mm external diameter stainless steel tube having a capacity of 15 ml catalyst composition.

The reaction mixture of air, aromatic compound and nitrogen is premixed and fed into the reactor at a molar ratio of 5: 1: 2. The reactor is maintained at 530-532 ° C and at atmospheric pressure. The hourly vapor velocity of the liquid flavorant guided through the catalyst is 0.23 h ^-1 and the contact time is 3.3 seconds. The particle size of the catalyst used is 20 to 35 mesh. The percent conversion per pass to the desired alkenylaromatic compound and the selectivity of the reaction are shown in Tables I to III and are calculated from the following equations:

% conversion = moles of reacted, alkylaromatic compound moles of introduced alkylaromatic compound

100 yields in one pass * = moles “alkenylaromatic compounds obtained moles introduced, alkylaromatic compounds x 100 moles of obtained alkenylaromatic compounds moles of reacted alkylaromatic compounds

100 ALIGN!

TABLE 1

Example Oxydehydrogenation of ethylbenzene to styrene % molar selectivity with respect to for styrene Catalyst % mole conversion of ethylbenzene % mole per pass of styrene yield Catalyst composition A N12P2O7 55  43 79 Catalyst composition B Mg2P2O7 71 61 86 Catalyst composition C La4 (P2O7) 3 55 41 75 Catalyst composition 'D Co7Fe ₃ Pi2O4i ₍ 5 27 Mar: 24 88 Catalyst composition 'E CO2P2O7 47 37 78 1 BÍ8P12O42 14 12.5 85 2 25% Bi8P12O42—75% BPO4 68 59 86 3 5% Cu ₁ .55 ^ il ^ 55 ^ 1 ^ 5t95 '% BPO4 51 42 82 4 FeioBio.7Pi2046 39 18 72 5 CO10BÍ0.7P12O41 55 48 86 6 CO7Fe ₃ Bi ₀ .7P 12θ42,5 59 50 85 7 50% 'C07Fe3BhPi2O43—50% ‘BPO4 62 53 85 8 C09.5Feo ₍ 5BiP'i2O ₄ 2 75 64 87 9 MgfFeiBiP22O42 65 55 84 ‘10 C09CrBí P12O42 74 65 89 11 Co ^ ai ^ 3i ₂ P 12Ο42 75 65 87 12 Co8Lag.5BI ₂ P12O42 69 60 87 13 CO9LaBÍP12.O42 79 71 90 14 Ko.0iCo9La1BiP · 12Ό42 78 70 90 15 Dec Co7Zn2LaiBiPiO) 42 73 66 90 16. Co9CeBíP13045 77 69 90 YJ Mg9LaiBiP22O42 78 70 90 18 CO9 ”D1” BIP12'O42 63 51 82 19 Dec Co ₉ 1 ^ (31TePi 2 O 4) 42.5 60 50 83 20 May COioSb1Pi2041.5 58 46 80 21 LPL OCOG ^ ₂ 041,5 52 43 83 22nd CO10Cd ₂ P12O42 49 42 87

TABLE II

Oxydehydrogenation of methylethylpyridine to methylvinylpyridine

Example number Catalyst % mole per conversion , (MeEt pyridine) % mole yield (Me vinylpyridine) % molar selectivity with respect to (Me vinylpyridine ..) 23 Co8BaFeBiPl ₂ O42 35 23 66 24 Co9CeBiPi3O45 32 2l 66 25 Mg ₉ La _B iP ₁₂ O ₄ 40 26 65

TABLE III

Oxydehydrogenation of diethylbenzene *) to divinylbenzene

Example number Catalyst % mole conversion of diethylbenzene % mole yield of ethylvinyl and divinylbenzene % Molar selectivity with respect to ethylvinyl and divinylbenzene 26 K _D - iCopCriB ^ P ^ O ^ 2 78 40 l9 76 *) Eastman T lQ3l, Μ. P mixture ^ 7 '...... ^: - * - '

SUBJECT

Claims (8)

A process for the oxydehydrogenation of alkylaromatic compounds to the corresponding alkenylaromatic compounds, wherein the alkylaromatic compounds contain at least one C 2 -C 6 alkyl group bonded to one aromatic ring and wherein the aromatic group is selected from mononuclear, fused dinucleic aromatic groups and the corresponding heterocyclic groups containing nitrogen atoms, in particular ethylbenzene on styrene, diethylbenzene on divinylbenzene, ethyltoluene on vinyltoluene, methylethylpyridine on methylvinylpyridine and ethylpyridine on vinylpyridine, characterized in that a gaseous mixture of alkylaromatics, molecular oxygen and optionally a dilution gas at up to 300 ° C is passed through C, wherein the catalyst composition is a combination of elements corresponding to formula I AaMbMcW ^ ePA, (I) where is And alkali metal or thallium, M one or more elements selected from the group consisting of nickel, cobalt, copper, manganese, magnesium, zinc, calcium, niobium, tantalum, strontium or barium, M ^l one or more of iron, chromium, uranium, thorium, - vanadium, titanium, lanthanum, or other rare earth metal, M ^for one or more elements selected from the group consisting of tin, boron, lead, germanium, aluminum, tungsten or molybdenum, VYNALEZU B - bismuth, tellurium, - arsenic, antimony, cadmium or - a mixture thereof, P - phosphorus aa zero to 20, b zero - to 20, c zero to 20, d zero to 4, e number 0, 1 to 20, y number 8 to 16, x number of oxygen atoms - needed to saturate and the sum of b + c + e is greater than - l. 2. Method of claim l wherein the gas mixture flows catalyst composition formed by the combination of elements corresponding to formula I wherein A, Μ ^{1 u} M, and B is as defined in claim l, and wherein a is zero to 2, b number 4 to 12, c number 0.2 to 4, d zero to 2, e number 0.5 to 5, y number 10 to 14. 3. The process of claim 1 wherein the molar ratio of oxygen to alkylaromatic compounds is 0.5-4. 4. The process of claim 3 wherein the mixture of reactants is passed through the catalyst composition at a temperature of 400 to 600 ° C. 5. The method of claim 4, wherein the contact time is 1 to 15 seconds. 6. A method according to claim 5, characterized in that the -plynná mixture through a catalyst composition formed by the combination of elements corresponding to formula I where M známe199528 cobalt, lanthanum M ^1, B, Bi, M ^11, A, P, a, b, c , d, e, y, x have the meaning given in point 1. 7. A process according to claim 5, wherein the gas mixture is passed through a catalyst composition comprising a combination of elements corresponding to formula I wherein M is cobalt, Mi iron and B tellurium, A, Μ ^π , P, a, b, c, 1 »d, e, y, x have the meaning given in point 1. 8. A method according to claim 5, characterized in that the "gas mixture results in a catalyst composition consisting of combinations of elements corresponding to formula I where M is Mg, M lanthanum and bismuth, B, A, M, ^U, P, a, b, c, d, e, y, x are as defined in 1.