JP3484729B2 - Method for producing ethylene - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing ethylene by oxidative dehydrogenation of ethane.

[0002]

2. Description of the Related Art Ethylene is industrially important as a basic raw material for various petrochemical products and polymer products. The low-temperature oxidative dehydrogenation of ethane to ethylene is described in "The Oxidative
Dehydrogenation of Ethane over Catalysts Contain
ing Mixed Oxides of Molybdenum and Vanadium ''
(Journal of Catalysis, 52, 116-132 (1978))
It is well known since the publication of. This paper describes molybdenum and vanadium as well as other transition metal elements (Ti, Cr, Mn, Fe, Co, Ni, N
A mixed oxide catalyst containing b, Ta and Ce) is disclosed. The catalyst is active for oxidative dehydrogenation of ethane to ethylene at temperatures as low as 200 ° C.

US Pat. No. 4,250,346, German Patent No. 26441
No. 07 and JP-A-52-42806 disclose the oxidative dehydrogenation of ethane to ethylene at temperatures below 450 ° C., where the catalyst is of the formula:

[0004]

[Table 3] Mo _a X _b Y _c (in the formula: X = Cr, Mn, Nb, Ta, Ti, V, and / or W, Y = Bi, Ce, Co, Cu, Fe, K, Mg, Ni , P, Pb, Sb, Si, Sn, Tl and /
Or U, a = 1, b = 0-2, c = 0-2). In the above formula, the numerical values of a, b, and c are the elements Mo present in the catalyst composition,
Represents the relative molar ratio of X and Y. The elements Mo, X and Y are present with oxygen in the catalyst composition.

The patent specifications and the like disclose various compositions. However, sufficient results have not been obtained for both the conversion rate of ethane and the yield of ethylene. For example, in Examples 57 and 58 of JP-A-52-42806, which is one of the examples showing the highest ethylene yield among these,
Ethane conversion of 53 at 400 ° C using Mo ₁₆ V ₈ Nb ₂ U ₁ catalyst
%, Ethylene yield 34%, ethane conversion 58%, ethylene yield 34% at 400 ° C. using Mo ₁₆ V ₄ W _1.6 Mn ₄ catalyst
Is shown.

US Pat. No. 4,524,236 and JP-A-61-1584
No. 9 discloses the oxidative dehydrogenation of ethane to ethylene at temperatures below 450 ° C., where the catalyst is of the formula:

[0007]

[Table 4] Mo _a V _b Nb _c Sb _d X _e (where: X = Li, Sc, Na, Be, Mg, Ca, Sr, Ba, Ti, Zr, Hf, Y, Ta,
At least one of Cr, Fe, Co, Ni, Ce, La, Zn, Cd, Hg, Al, Tl, Pb, As, Bi, Te, U, W. a = 0.5-0.9, b = 0.1-0.4, c = 0.001-0.2, d = 0.001-0.1, e = 0.001-1.0) Calcination consisting of elements Mo, V, Nb, Sb and X It is a composition. In the above formula, the numerical values of a, b, c, d, and e are the elements Mo, V, and
It represents the relative molar ratio of Nb, Sb and X. Elements Mo, V,
Nb, Sb and X are present with oxygen in the catalyst composition.

The above patent specifications disclose a variety of compositions. However, sufficient results have not been obtained for both the conversion rate of ethane and the yield of ethylene. For example, one of the examples showing the highest ethylene yield is US Pat.
No. 236, Example 6, which is Mo ₁ V _0.43 Nb.
_It shows ethane conversion of 71% and ethylene yield of 51.1% at 400 ° C. using _0.11 Sb _0.07 Bi _0.03 catalyst.

Japanese Kokai 64-85945 discloses the production of acetic acid from ethane, ethylene and oxygen, in which the catalyst is:

[0010]

[Table 5] (A) Mo _x V _y Z _z (in the formula: Z = none, or Nb, Sb, Li, Sc, Na, Be, Mg, Ca, S
r, Ba, Ti, Zr, Hf, Y, Ta, Cr, Fe, Co, Ni, Ce, La, Zn, Cd, Hg, Al, T
One or more of l, Pb, As, Bi, Te, U and W. x = 0.5-0.9, y = 0.1-0.4, z = 0.01-1) (The numerical values of x, y, and z represent the relative molar ratios of the elements Mo, V, and Z present in the catalyst composition, respectively. Element M
o, V and Z are present with oxygen in the catalyst composition. )
And (B) at least one catalyst selected from the group consisting of ethylene hydration catalysts and ethylene oxidation catalysts.

Examples of the patent specification are catalyst (A) compositions
As MoVNbSbCa or MoVNb mixed oxide only
There is. Also disclosed is the oxidation reaction of ethane alone,
The conversion of ethane is low and the selectivity of ethylene produced is sufficient.
Not expensive for minutes. For example, in Example 7, ethane
87%, oxygen 6.5%, nitrogen 6.5% as source gas
_0.7V_0.25Nb_0.02Sb_0.01Ca_0.01O_xAnd powder molecular
Reacted on a combination catalyst with BLU-Z-105 (UCC)
The conversion rate of ethane was 3 mol%,
The selectivity was 56 mol%.

[0012]

In these documents relating to the technology for obtaining ethylene by the oxidative dehydrogenation reaction of ethane, a composite oxide catalyst containing Mo or Mo and V is effective for the oxidative dehydrogenation reaction. Although it has been shown to be possible, it has not yet been disclosed to show catalytic performance that can withstand practical use. That is, the maximum yield of ethylene from ethane is substantially at most 50 mol%.

[0013]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve such problems, and as a result, the catalyst composition contains molybdenum, vanadium, tellurium and oxygen as essential components, and their powder X-ray diffraction In the production of ethylene by the oxidative dehydrogenation of ethane, the catalyst having a characteristic pattern does not cause the presence of halides in the reaction system, and at a relatively low temperature of about 300 to 450 ° C. The inventors have found that the target ethylene can be produced with high activity and high selectivity, and have reached the present invention.

That is, the gist of the present invention is a method for producing ethylene by contacting ethane with a molecular oxygen-containing gas at an elevated temperature, wherein the catalyst composition comprises molybdenum, vanadium, tellurium and It contains oxygen as an essential component, and its powder X-ray diffraction is mainly shown in Table-1.
The method for producing ethylene is characterized by including a complex metal oxide having a characteristic pattern shown in FIG.

[0015]

[Table 6] Table-1 ──────────────────────── Diffraction angle 2θ (± 0.4 °) Relative peak intensity ──── ──────────────────── 22.1 ° (100) 28.2 ° (400-3) 36.2 ° (80-3) 45.1 ° ( 40 to 3) 50.0 ° (50 to 3) ──────────────────────── (Cu-Kα ray is used as the X-ray source. The numbers in the figure show the relative peak strength when the peak strength of 22.1 ° is 100.) The present invention will be described in detail below.

The essence of the present invention uses a complex oxide solid catalyst containing molybdenum (Mo), vanadium (V), tellurium (Te) and oxygen (O) as essential components and having the above-mentioned specific X-ray diffraction pattern. To do. As a specific example of the catalyst, for example, a composite metal oxide constituting the catalyst is M
O, V, Te, X and oxygen as essential components (X is niobium, tantalum, tungsten, titanium, aluminum, zirconium, chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, antimony, bismuth. , One or more elements selected from the group consisting of boron, indium, cerium, lithium, sodium, potassium, rubidium and cesium), and the presence ratio of each of the above essential components to the total of the above essential components excluding oxygen,

[0017]

Table 7 0.25 <r _Mo <0.98 0.003 <r _V <0.5 0.003 <r _Te <0.5 0.003 <r _X <0.5 (where r _Mo , r _V , r _Te and r _X each represent a mole fraction of Mo, V, Te and X with respect to the total number of moles of the above essential components excluding oxygen). Of the above-mentioned elements, the component X is preferably an element of Group VB or VIB of the Periodic Table and Bi, and niobium is particularly preferable.

These catalysts are prepared, for example, as follows. That is, first, an aqueous solution containing ammonium metavanadate and an aqueous solution of telluric acid are sequentially added to a predetermined amount of an aqueous solution of ammonium paramolybdate at an amount ratio such that the atomic ratio of each metal element becomes a predetermined ratio. Then
Further, an aqueous solution of the component X is added in a quantity ratio such that the atomic ratio of the metal elements becomes a predetermined ratio, and the mixture is evaporated to dryness. The dry solid is heated at 350 ° C to 65 ° C under the condition that the oxygen concentration is substantially lower than that of air.
The catalyst is calcined at a high temperature of 0 ° C., especially about 450 ° C. to 600 ° C. The mixed metal oxide catalyst prepared in this manner mainly exhibits the powder X-ray diffraction pattern shown in Table 1 above, but the oxygen concentration in the feed gas during calcination is particularly important, and it is substantially the same as air. It is preferable to perform the firing at a lower oxygen concentration, and it is particularly preferable to perform the firing in an atmosphere of an inert gas such as nitrogen, argon, or helium, or in the flow of these, or in vacuum.

It should be noted that instead of the ammonium paramolybdate shown above, MoO ₃ , MoO ₂ , MoCl ₅ ,
Phosphomolybdic acid, silicomolybdic acid, Mo (OR) ₅
(R is an alkyl group having 1 to 10 carbon atoms) or molybdenyl acetylacetonate can be used. Instead of ammonium metavanadate, for example, V ₂ O ₅ , V ₂ O ₃ , vanadyl can be used. Acetylacetonate,
NH ₄ VO ₃ , VO (OR) ₃ (R represents 1 to 10 carbon atoms
Alkyl group), VCl ₄ or VOCl ₃ can be used, and TeO ₂ or the like can be used instead of telluric acid. Further, as the raw material for X, its oxide, halide, carboxylate, alkoxide, acetylacetonate, ammonium halide salt, ammonium carboxylate or the like can be used. Further, a heterocoordinated complex of molybdenum and vanadium, such as molybdovanadric acid, may be used.

As for the content of each metal element in the catalyst of the present invention, r _Mo is usually 0.25 to 0.98, preferably 0.5 to 0.7, and r _V is usually 0.003 to.
0.5, preferably 0.06 to 0.3, r _Te is usually 0.003 to 0.5, preferably 0.05 to 0.2, and as X, for example, when X is niobium, r _Nb is usually 0.003 to 0.5, preferably 0.02 to 0.15.

These catalysts can be used alone, but can also be used together with a well-known carrier such as silica, alumina, aluminosilicate, titania, zirconia and the like. The catalyst is formed into a proper particle size and shape according to the reaction scale, method, etc., and then sized. The method of the present invention produces ethylene by subjecting ethane to a gas phase catalytic oxidation reaction using the above-mentioned catalyst.

The reactor system is not particularly limited, but a reaction system such as a fixed bed, a fluidized bed or a moving bed can be preferably used. The raw material ethane is not particularly limited in purity, and for example, methane, water, carbon monoxide, carbon dioxide, propane, butane, etc. may be mixed as impurities. Further, the oxidation reaction in the present invention is performed by oxygen existing in the feed gas. When oxygen is present in the feed gas, the oxygen may be pure oxygen gas, but it is generally economical to use an oxygen-containing gas such as air because purity is not particularly required.

When air is used, the ratio of air to be fed to the reaction is usually in a wide range of 1 to 50 mole times relative to ethane, and suitable results are obtained, and particularly in the case of 3 to 23 mole times. It shows extremely high ethylene selectivity. The reaction is usually carried out under atmospheric pressure, but it may be carried out under low pressure or under reduced pressure.

The method of the present invention is carried out, for example, at 200 to 550 ° C.
Can be carried out at a reaction temperature of 3, with 3 being particularly preferred.
It is about 50 to 450 ° C. Further, the gas space in the gas phase reaction rate SV [hr ^-1] is, 100～5000Hr ^-1
Suitable results are obtained in a wide range of, preferably in the range of 200 to 2000 hr ⁻¹ . As a diluent gas for adjusting the space velocity and the oxygen partial pressure, nitrogen, argon, an inert gas such as helium or carbon dioxide,
A diluent gas such as water vapor can be used.

When the ethane oxidation reaction is carried out by the method of the present invention, carbon monoxide, carbon dioxide, acetic acid and the like are produced as by-products in addition to ethylene, but the amount produced is extremely small.

[0026]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded. The ethane conversion rate (%), ethylene selectivity (%), and ethylene yield (%) in the following examples are shown by the following equations, respectively.

[0027]

[Equation 1] Conversion rate of ethane (%) = (mol number of consumed ethane / mol number of supplied ethane) × 100 Ethylene selectivity (%) = (mol number of produced ethylene / mol number of consumed ethane) × 100 Yield of ethylene (%) = (mol number of produced ethylene / mol number of supplied ethane) × 100

Examples 1 to 8 Ammonium metavanadate 1.7 was prepared by dissolving 8.83 g of ammonium paramolybdate in 25 g of water.
An aqueous solution of 5 g dissolved in 60 g of water and telluric acid 2.6
An aqueous solution of 4 g dissolved in 5 g of water was added. Further, an aqueous solution of 2.66 g of ammonium niobium oxalate dissolved in 12 g of water was added. Silica sol was added to the produced orange slurry and dried to dryness to obtain an orange solid, which was calcined at 600 ° C. for 2 hours in a nitrogen stream to give a composition ratio of Mo.
_{1.0 V 0.30 Nb 0.1 2 Te 0.23} O n / SiO 2 = 90/10
A (wt%) black solid was obtained (n determined by the oxidation states of other elements).

Powder X-ray diffraction measurement of the composite metal oxide thus obtained was carried out (Cu-Kα as X-ray source).
Line), and the diffraction angle 2θ (°) is 22.1 (10
0), 28.2 (59.7), 36.2 (18.1),
Major diffraction peaks were observed at 45.1 (13.9) and 50.0 (9.7). (The number in parentheses indicates the relative peak strength when the peak strength of 22.1 ° is 100.) Next, the composite metal oxide was mixed with a tablet molding machine to give 5
After being molded into mmΦ × 3 mmL, it was pulverized, sieved to 16 to 28 mesh, and used as a catalyst.

0.5 ml of the catalyst was charged into the reactor, and Table 2 was used.
Gas was supplied at the reaction temperature, the space velocity SV, and the molar ratio of ethane and air shown in (1) to carry out the gas phase catalytic reaction. The results are shown in Table-2.

Example 9 Ammonium iron oxalate instead of ammonium niobium oxalate
Was the same as Example 1 except that silica sol was not used.
The raw materials are mixed and dried in a similar manner to obtain an orange solid.
The composition ratio is Mo after firing for 2 hours at 500 ° C under air flow._1.0V
_0.40Fe_0.1Te _0.2O_nTo obtain a black solid (n is
Determined by the oxidation state of other elements). Get in this way
Powder X-ray diffraction measurement of mixed metal oxide
(Use Cu-Kα ray as X-ray source), diffraction angle 2θ
(°) is 22.1 (100), 28.2 (20
0), 36.2 (38.5), 45.1 (11.5),
A major diffraction peak was observed at 50.0 (25.0).
(The number in parentheses is the peak intensity of 22.1 ° is 100
Indicates the relative peak strength). Next, the compound gold
The metal oxide was formed into 5 mmφ × 3 mmL using a tablet molding machine.
After molding, crush and sieve to 16-28 mesh,
Served as Charge 0.5 ml of catalyst into the reactor and
2 reaction temperature, space velocity SV and ethane and air
Gas was supplied at a molar ratio of and the gas phase catalytic reaction was carried out. Conclusion
The results are shown in Table-2.

Example 10 The composition ratio was Mo _1.0 V in the same manner as in Example 9 except that metatungstic acid was used instead of ammonium iron oxalate.
A black solid of _0.40 W _0.1 Te _0.2 O _n was obtained (n determined by the oxidation states of other elements). The powder X-ray diffraction of the composite metal oxide thus obtained was measured (X
Cu-Kα ray is used as a radiation source) and diffraction angles 2θ (°) are 22.1 (100), 28.2 (122), 3
6.2 (38.4), 45.1 (13.0), 50.0
A major diffraction peak was observed at (20.8) (the number in parentheses indicates the relative peak intensity when the peak intensity at 22.1 ° is 100). Next, after molding the composite metal oxide into 5 mmφ × 3 mmL using a tablet molding machine,
It was crushed, sieved to 16-28 mesh, and used as a catalyst. 0.5 ml of the catalyst was filled in the reactor, and gas was supplied at the reaction temperature, the space velocity SV and the molar ratio of ethane and air shown in Table 2 to carry out the gas phase catalytic reaction. The results are shown in Table-2.
Shown in.

Example 11 The composition ratio was Mo _1.0 V _0.40 B in the same manner as in Example 9 except that bismuth oxalate was used in place of ammonium iron oxalate.
A black solid of i _0.1 Te _0.2 O _n was obtained (n is determined by the oxidation state of other elements). When powder X-ray diffraction measurement of the composite metal oxide thus obtained was performed (Cu-Kα ray was used as an X-ray source), the diffraction angle 2θ (°) was 22.1 (100), 28. 2 (177), 36.
2 (54.5), 45.1 (11.4), 50.0 (3
A major diffraction peak was observed at 5.0) (the number in parentheses indicates the relative peak intensity when the peak intensity at 22.1 ° is 100). Next, the composite metal oxide was molded into a size of 5 mmΦ × 3 mmL using a tablet molding machine, pulverized, and sieved to 16 to 28 mesh to serve as a catalyst.
0.5 ml of the catalyst was filled in the reactor, and gas was supplied at the reaction temperature, the space velocity SV and the molar ratio of ethane and air shown in Table 2 to carry out the gas phase catalytic reaction. The results are shown in Table-2.

Example 12 The composition ratio was Mo _1.0 V _0.40 Cr in the same manner as in Example 9 except that chromium nitrate was used instead of ammonium iron oxalate.
_0.1 Te _0.2 O _n a black solid was obtained (n is determined by the oxidation state of the other elements). When powder X-ray diffraction measurement of the thus obtained composite metal oxide was carried out (Cu-Kα ray was used as an X-ray source), a diffraction angle 2θ (°) was obtained.
22.1 (100), 28.2 (134), 36.2
(37.6), 45.1 (14.1), 50.0 (2
A major diffraction peak was observed in 5.9) (the number in parentheses indicates the relative peak intensity when the peak intensity at 22.1 ° is 100). Next, the composite metal oxide was molded into a size of 5 mmΦ × 3 mmL using a tablet molding machine, pulverized, and sieved to 16 to 28 mesh to serve as a catalyst.
0.5 ml of the catalyst was filled in the reactor, and gas was supplied at the reaction temperature, the space velocity SV and the molar ratio of ethane and air shown in Table 2 to carry out the gas phase catalytic reaction. The results are shown in Table-2.

Example 13 The composition ratio was Mo _1.0 V _0.40 M by the same method as in Example 9 except that manganese oxalate was used instead of ammonium iron oxalate.
A black solid of n _0.1 Te _0.2 O _n was obtained (n determined by the oxidation states of other elements). When powder X-ray diffraction measurement of the composite metal oxide thus obtained was performed (Cu-Kα ray was used as an X-ray source), the diffraction angle 2θ (°) was 22.1 (100), 28. 2 (122), 36.
2 (30.3), 45.1 (12.5), 50.0 (1
A major diffraction peak was observed at 8.0) (the number in parentheses indicates the relative peak intensity when the peak intensity at 22.1 ° is 100). Next, the composite metal oxide was molded into a size of 5 mmΦ × 3 mmL using a tablet molding machine, pulverized, and sieved to 16 to 28 mesh to serve as a catalyst.
0.5 ml of the catalyst was filled in the reactor, and gas was supplied at the reaction temperature, the space velocity SV and the molar ratio of ethane and air shown in Table 2 to carry out the gas phase catalytic reaction. The results are shown in Table-2.

Example 14 A composition ratio of Mo _1.0 V was obtained in the same manner as in Example 9 except that zirconium nitrate was used instead of ammonium iron oxalate.
A black solid of _0.40 Zr _0.1 Te _0.2 O _n was obtained (n determined by the oxidation states of other elements). When powder X-ray diffraction measurement of the composite metal oxide thus obtained was performed (Cu-Kα ray was used as an X-ray source), a diffraction angle 2θ
(°) is 22.1 (100), 28.2 (30
0), 36.2 (57.9), 45.1 (26.3),
A major diffraction peak was observed at 50.0 (42.1) (the numbers in parentheses indicate a peak intensity of 22.1 ° of 100).
Indicates the relative peak strength). Next, the composite metal oxide was molded into a size of 5 mmΦ × 3 mmL using a tablet molding machine, pulverized, and sieved to 16 to 28 mesh to serve as a catalyst. Charge 0.5 ml of catalyst into the reactor and
Gas was supplied at the reaction temperature, the space velocity SV, and the molar ratio of ethane and air shown in 2 to carry out the gas phase catalytic reaction. The results are shown in Table-2.

Example 15 The composition ratio was Mo _1.0 V _0.40 K in the same manner as in Example 9 except that potassium nitrate was used instead of ammonium iron oxalate.
_0.1 Te _0.2 O _n a black solid was obtained (n is determined by the oxidation state of the other elements). When powder X-ray diffraction measurement of the thus obtained composite metal oxide was carried out (Cu-Kα ray was used as an X-ray source), a diffraction angle 2θ (°) was obtained.
22.1 (100), 28.2 (101), 36.2
(27.8), 45.1 (16.7), 50.0 (2
A major diffraction peak was observed in 2.2) (the number in parentheses indicates the relative peak intensity when the peak intensity of 22.1 ° is 100). Next, the composite metal oxide was molded into a size of 5 mmΦ × 3 mmL using a tablet molding machine, pulverized, and sieved to 16 to 28 mesh to serve as a catalyst.
0.5 ml of the catalyst was filled in the reactor, and gas was supplied at the reaction temperature, the space velocity SV and the molar ratio of ethane and air shown in Table 2 to carry out the gas phase catalytic reaction. The results are shown in Table-2.

[0038]

[Table 8] Table-2 ──────────────────────────────────── Example ethane / air SV temperature Ethane conversion ethylene yield ethylene selectivity (molar ratio) (hr ^-1 ) (° C) (%) (%) (%) ───────────────────── ──────────────── 1 1/5 870 430 930 90.5 73.4 81.2 2 1/5 1750 460 89.5 71.6 80.0 3 1/5 520 410 90.0 73.2 81.4 4 1/5 170 370 89.0 71.0 79.8 5 1/3 580 400 77.8 68.2 87.6 6 1/15 460 400 88.9 71.0 79.9 7 1/15 460 360 56.7 51.9 91.5 8 1/23 680 410 410 86.8 70.2 80 8 9 1/5 520 430 28.4 13.1 46.3 10 1/5 520 390 71.3 42.2 59.2 11 1/5 520 470 58.9 29.8 50.5 12 1/5 520 430 54.1 25.7 47.5 13 1/5 520 430 16.4 5.6 34.3 14 1/5 520 430 27.2 10.6 38.9 15 1/5 520 430 40.4 10.6 26.3 ────────────────────────────────────

[0039]

According to the present invention, ethylene can be produced in a high yield and a high selectivity by low temperature oxidative dehydrogenation of ethane.

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C07C 5/48 C07C 5/333 C07C 11/04

Claims (2)

(57) [Claims] 1. A method of producing ethylene by contacting ethane with a molecular oxygen-containing gas at a elevated temperature with a catalyst composition, the catalyst composition comprising molybdenum, vanadium, tellurium and oxygen as essential components. A method for producing ethylene, characterized in that its powder X-ray diffraction mainly contains a composite metal oxide having a characteristic pattern shown in Table 1. [Table 1] Table-1 ──────────────────────── Diffraction angle 2θ (± 0.4 °) Relative peak intensity ──── ──────────────────── 22.1 ° (100) 28.2 ° (400-3) 36.2 ° (80-3) 45.1 ° ( 40 to 3) 50.0 ° (50 to 3) ──────────────────────── (Cu-Kα ray is used as the X-ray source. The numbers in the figure show the relative peak strength when the peak strength of 22.1 ° is 100.) 2. The catalyst composition contains Mo, V, Te, X and oxygen as essential components (where X is niobium, tantalum,
Tungsten, titanium, aluminum, zirconium,
One or more elements selected from the group consisting of chromium, manganese, iron, ruthenium, cobalt, rhodium, nickel, palladium, platinum, antimony, bismuth, boron, indium, cerium, lithium, sodium, potassium, rubidium and cesium. Represent ), The ratio of the presence of each of the above essential components to the total of the above essential components excluding oxygen is as follows: 0.25 <r _Mo <0.98 0.003 <r _V <0.5 0.003 <r _Te <0.5 0.003 <r _X <0.5 (where r _Mo , r _V , r _Te and r _X are the moles of Mo, V, Te and X relative to the total moles of the above essential components excluding oxygen, respectively) The method for producing ethylene according to claim 1, further comprising a mixed metal oxide having a ratio of 4).