JPH059133A - Production of ethane and ethylene from methane - Google Patents

Abstract

PURPOSE:To produce ethane and ethylene by partially oxidizing methane or a natural gas containing methane with oxygen or an oxygen-containing gas. CONSTITUTION:Methane or a natural gas containing methane is partially oxidized with oxygen or a gas containing the oxygen in the presence of a catalyst containing an alkali metal, the group IIa metal and the group Va metal at 600-1000 deg.C to produce ethane and ethylene. The catalyst used has an excellent catalytic activity and an excellent selectivity for the production of 2C hydrocarbons.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing ethane and ethylene by reacting methane or a natural gas containing methane in the presence of oxygen or an oxygen-containing gas.

[0002]

2. Description of the Related Art Methane is an abundant resource that exists abundantly in the world as a main component of natural gas, but due to its low reactivity, most of it is consumed as a fuel and used as a raw material for the chemical industry. The law is limited. However,
In 1982, Keller and Virgin produced ethane and ethylene by partial oxidation of methane in the presence of oxygen using various metal oxides as catalysts. The production of ethane and ethylene was published in the United States, Journal of Catalysis, Vol. Volume 73, 9-
Reported on page 19. Since then, many catalysts useful for this reaction called oxidative coupling reaction of methane have been reported. If you classify these, many of them are
Alkali metals and alkaline earths, rare earth metals such as lanthanides, or catalysts combining these are used. However, in most of the cases described above, the conversion rate of methane and the selectivity of C ₂ hydrocarbons in the product are still low, and the performance as a practical catalyst is not so high. Therefore,
It is desired to develop a catalyst having higher activity and higher selectivity. On the other hand, Group Va metals such as vanadium are used in, for example, SO ₂ oxidation as a catalytic sulfuric acid production process, maleic anhydride production from benzene, or phthalic anhydride production from O-xylene or naphthalene. In addition, it has oxidative activity. However, if this is used alone for the oxidation of aliphatic hydrocarbons, the reaction will proceed to CO and CO ₂ because the oxidizing power is too strong. That is, the partial oxidation reaction such as the production of ethane and ethylene from methane has a drawback of poor selectivity. Therefore, there are few reports that a catalyst containing a Group Va metal such as vanadium as a main component has high selectivity in the oxidative coupling reaction. In addition, JP-A-63-636
Japanese Patent Laid-Open No. 25 discloses that ethane and ethylene are produced using a catalyst having a composition containing a Group Va metal, but this technique has a drawback that a high selectivity cannot be obtained. is there.

[0003]

However, the prior art has the above-mentioned drawbacks, and the catalyst having a high selectivity has not yet been elucidated. It is an object of the present invention to solve such conventional problems and provide a method for efficiently producing ethane and ethylene with a catalyst having a high selectivity.

[0004]

As a result of various studies on the catalyst for oxidative coupling of methane, the present inventors have found that
Hydrocarbons having 2 or more carbon atoms such as ethane and ethylene can be produced with high selectivity by mixing an alkali metal and a Group IIa metal with a Group Va metal compound that has been conventionally used as a catalyst for a complete oxidation reaction. Based on this finding, the present invention has been completed. The present invention is
In the process for producing ethane and ethylene, in order to improve the conversion rate of methane and the selectivity of ethane and ethylene, in the presence of a catalyst composed of a system in which an alkali metal, a group IIa metal and a group Va metal of the periodic table are combined. At 600 to 1000 ° C., methane or natural gas containing methane is partially oxidized with oxygen or oxygen-containing gas. In order to further improve the conversion rate of methane and the selectivity of ethane and ethylene,
The addition amount of the Group IIa metal is 0.3 to 5.0 in atomic ratio to the alkali metal, and the addition amount of the Group Va metal is 0.05 to 2.0 in atomic ratio to the alkali metal. IIa
The atomic ratio to the group metal is 2.0 or less.

The present invention will be described in detail below. In the present invention, lithium, sodium, potassium or the like is used as the alkali metal constituting the catalyst, and magnesium, calcium, strontium, barium or the like is used as the Group IIa (Group 2a) metal constituting the catalyst,
Further, vanadium, niobium, tantalum, vanadium or the like is used as the Group Va metal constituting the catalyst. When the alkali metal is 1, the mixing ratio of these metals is IIa.
The atomic ratio of the group metal is 0.3 to 5.0, preferably 0.5 to
2.0, most preferably 0.6-1.2
The a-group metal has an atomic ratio of 0.05 to 2.0, preferably 0.
It is used in the range of 1 to 1.0, most preferably 0.15 to 0.5. Further, when the group IIa metal is 1, the group Va metal is used in an atomic ratio of 2.0 or less, preferably 1.0 or less, and most preferably 0.5 or less. If the atomic ratio of the Group IIa metal when the alkali metal is 1 is less than 0.3, the reaction activity becomes low, and if the atomic ratio of the Group IIa metal is more than 5.0, the selectivity is increased. And the decline of activity becomes faster. On the other hand, when the alkali metal is 1, the Va
When the atomic ratio of the group metal is less than 0.05, the reaction activity becomes low, and when the atomic ratio of the group Va metal is more than 2.0, the selectivity is lowered. Further, if the atomic ratio of the Group Va metal is 2.0 or more when the Group IIa metal is 1, the selectivity is lowered. Therefore, the atomic ratio of the Group IIa metal to the alkali metal is in the range of 0.3 to 5.0, the atomic ratio of the Group Va metal is in the range of 0.05 to 2.0, and the atomic ratio to the Group IIa metal is The atomic ratio of the Group Va metal must be 2.0 or less.

The catalyst used in the present invention is obtained as follows. That is, a metal compound is weighed and accommodated in an alumina crucible so as to have a predetermined atomic ratio, and water is added to this and sufficiently kneaded. Then, after evaporating to dryness at 100 ° C., baking is performed at 600 to 1100 ° C. to prepare. As the metal compound, oxides, carbonates, nitrates and the like are usually used, but they are not particularly limited, and various compounds can be used. The catalyst thus obtained can be crushed and used as a powder of 100 mesh or more, but if necessary, it is further crushed after molding with a compression molding machine, preferably 16-
It can also be used as a 32 mesh granular material. Also, these catalysts can be used on a carrier such as quartz sand, alumina, magnesia or the like.

In carrying out the oxidative coupling reaction of methane using the above catalyst, methane and oxygen are converted into CH ₄ /
O ₂ (molar ratio) = 1 to 100, preferably 2 to 30 are used as a mixture. At this time, of course, an inert gas such as helium, argon or nitrogen may coexist as a diluent. These mixed gases are supplied to a reaction tube filled with a catalyst, and the reaction is usually performed at 600 to 1000 ° C, preferably 700 to 850 ° C. The reaction is usually carried out under atmospheric pressure, but if necessary, it may be carried out under reduced pressure or increased pressure. Methane separated from natural gas is usually used in the reaction, but methane produced from coal or other substances may be used. Furthermore, natural gas itself containing methane can also be used as a raw material. Oxygen that has been cryogenicly separated from air or that has been concentrated by a gas separation membrane can be used. Furthermore, it is possible to use oxygen in the air as it is. When the present invention is carried out, the catalyst may be used in any of a fixed bed, a moving bed and a fluidized bed.

[0008]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited thereto. The results of Examples 1 to 6 and Comparative Examples 1 and 2 are shown in Tables 1 and 2. Example 1 (1) Preparation of catalyst In an alumina crucible, sodium carbonate as an alkali metal, magnesium oxide as a Group IIa metal and tantalum pentoxide as a Group Va metal were added Na: Mg: Ta = 1: 1.
It was weighed and stored so as to have an atomic ratio of 1: 0.3, water was added to this, and the mixture was sufficiently kneaded, evaporated to dryness at 100 ° C., and then baked at 900 ° C. (2) Reaction test 1 g of the above catalyst was filled in an alumina reaction tube, and a mixed gas of CH ₄ : O ₂ = 90: 10 was flowed at a flow rate of 100 ml / min at 750 and 800 ° C. under atmospheric pressure to cause reaction. It was The reaction product obtained by the above operation was introduced into a gas chromatograph for analysis using a sampling loop attached to the outlet of the reaction tube. The analysis results are shown in Table 1. In Table 1, the methane conversion rate and the oxygen conversion rate represent the ratios of reacted methane and oxygen, and the C ₂ ⁺ selectivity represents the composition ratio of hydrocarbons having 2 or more carbon atoms in the reaction product.

Example 2 A catalyst was prepared and reacted in the same manner as in Example 1 except that niobium pentoxide was used as the Group Va metal. The results are shown in Table 1.
Shown in. Example 3 A catalyst was prepared and reacted in the same manner as in Example 1 except that vanadium pentoxide was used as the Group Va metal. The results are shown in Table 1. Example 4 A catalyst was prepared and reacted in the same manner as in Example 1 except that calcium oxide was used as the Group IIa metal. The results are shown in Table 1. Example 5 A catalyst was prepared and reacted in the same manner as in Example 3 except that calcium oxide was used as the Group IIa metal. The results are shown in Table 1. Example 6 A catalyst was prepared and reacted in the same manner as in Example 2 except that barium oxide was used as the Group IIa metal. The results are shown in Table 1.
Shown in.

[0010]

[Table 1]

Comparative Example 1 A catalyst was prepared and reacted in the same manner as in Example 1 except that the Group Va metal was not added. The results are shown in Table 2. Comparative Example 2 A catalyst was prepared and reacted in the same manner as in Example 4 except that the Group Va metal was not added. The results are shown in Table 2.

[0012]

[Table 2]

[0013]

According to the present invention, the alkali metal and the IIa
Oxidative coupling reaction of methane because methane or a natural gas containing methane is partially oxidized with oxygen or an oxygen-containing gas at 600 to 1000 ° C. in the presence of a catalyst composed of a group metal group and a group Va metal combined system. At
The conversion of methane and the selectivity of C ₂ ⁺ compounds can be significantly increased. In addition, for alkali metals, IIa
The addition amount of the group metal is in the range of 0.3 to 5.0 in atomic ratio, the addition amount of the group Va metal is in the range of 0.05 to 2.0 in atomic ratio, By setting the addition amount of the Group Va metal to be 2.0 or less in atomic ratio, the selectivity and the conversion rate can be further increased.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kiyoshi Otsuka             16-605 1-3-3 Etchujima, Koto-ku, Tokyo

Claims (7)

[Claims] 1. In the presence of a catalyst comprising a system comprising a combination of an alkali metal, a group IIa metal of the periodic table and a group Va metal,
A process for producing ethane and ethylene from methane, which comprises partially oxidizing methane or a natural gas containing methane with oxygen or an oxygen-containing gas at 00 to 1000 ° C. 2. The method for producing ethane and ethylene from methane according to claim 1, wherein the Group IIa metal is magnesium. 3. The method for producing ethane and ethylene from methane according to claim 1, wherein the Group IIa metal is calcium. 4. The method for producing ethane and ethylene from methane according to claim 1, wherein the Group Va metal is niobium. 5. The method for producing ethane and ethylene from methane according to claim 1, wherein the Group Va metal is tantalum. 6. The method for producing ethane and ethylene from methane according to claim 1, wherein the Group Va metal is vanadium. 7. The amount of the Group IIa metal added to the catalyst is 0.3 to 5.0 in atomic ratio with respect to the alkali metal,
And the addition amount of the Group Va metal is 0.05 to 2.0 in atomic ratio to the alkali metal, and the addition amount of the Group Va metal is 2.0 or less in atomic ratio to the Group IIa metal. 2. The method for producing ethane and ethylene from methane according to claim 1.