JPH0438732B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing hydrocarbons having two or more carbon atoms, such as ethane and ethylene, using methane as a raw material. [Prior Art] Methane is abundant as a main component of natural gas, but its low reactivity makes it difficult to use as a raw material for chemical industry. Therefore, attempts have been made to develop methods for converting methane into more active substances such as ethane and ethylene by oxidative coupling. A method using a lithium solid solution MgO catalyst (Li/MgO) as a method for producing hydrocarbons with carbon numbers of 2 or more, such as ethane and ethylene, from gases containing methane such as natural gas in the presence of oxygen (Journal of the Catalyst Society 27 , 6, p199, 1985), Mn, Sn,
A method using Pb, Sb, Bi, Tl, or Cd as a catalyst (J.Catalysis 73 , 9-19, 1982) is known. However, these methods have not yet yielded satisfactory results in terms of selectivity of methane to ethane and ethylene. [Problems to be Solved by the Invention] The present invention uses a catalyst that has not been known as a catalyst for oxidative coupling of methane, thereby improving the selectivity of methane to ethane and ethylene. A method for producing ethylene is provided. [Means for Solving the Problems] As a result of various studies on catalysts for oxidative coupling of methane, the present inventor found that by using a catalyst containing a specific metal compound, ethane can be extracted from methane with extremely high selectivity. It was discovered that ethylene could be produced, and based on this knowledge, the present invention was completed. That is, the method for producing hydrocarbons of the present invention involves contacting methane with a catalyst in the presence of oxygen gas to produce hydrocarbons having two or more carbon atoms. , strontium carbonate, and strontium oxide, or one or more of the above-mentioned metal compounds further containing one or more alkali metals. The catalyst used in the present invention can be prepared, for example, as follows. When one or more metal compounds selected from calcium carbonate, calcium oxide, barium carbonate, barium oxide, strontium carbonate, and strontium oxide are powder, water is added to the powder to make it moist. This is pelletized while still wet, and then 300
Bake at ~900°C for 0.5 to 30 hours. If the above compound is solid, it is ground to an appropriate size and then heated in air at 300 to 900°C for 0.5 to 30 hours.
Bake for an hour. Further, the catalyst of the present invention can contain one or more alkali metals in addition to calcium, barium, and strontium. Examples of alkali metals that can be contained include lithium,
Potassium, sodium and rubidium may be mentioned. Inclusion of these metals is advantageous in terms of increasing selectivity to ethane and ethylene and improving yield. The content of alkali metal is preferably 0.1 to 50 mol%. As the alkali metal compound, for example, halogen compounds such as lithium, potassium, sodium, rubidium, carbonates, nitrates, hydroxides, etc. are used. A catalyst containing an alkali metal in addition to calcium, barium and strontium can be prepared, for example, by an impregnation method as follows. By adding the calcium, barium and strontium compounds described above to an aqueous solution or suspension of one or more alkali metal compounds, the calcium, barium and strontium compounds are impregnated with the alkali metal compounds and evaporated. Dry by heating to 100-200℃. Then, it is baked in air at 300-900°C for 0.5-30 hours. The obtained catalyst is used after being pulverized or pelletized by a compression method, if necessary. Further, the catalyst of the present invention can also be used by being supported on a commonly used carrier such as silica gel or alumina by a conventional method. Methane was added to the catalyst thus obtained at a rate of 500
Contact in the presence of oxygen gas at ~1000°C yields hydrocarbons with higher carbon numbers than methane. When the reaction temperature is less than 500°C, the reaction hardly progresses, and when the reaction temperature exceeds 1000°C, the catalyst deteriorates rapidly. The methane used in the method for producing hydrocarbons of the present invention can be not only methane itself but also methane in natural gas. Furthermore, oxygen gas in the air can also be used. In the methane and oxygen reaction system, CH ₄ /O ₂ (molar ratio) = 0.1 ~
100 to perform a catalytic partial oxidation reaction. Further, in addition to methane and oxygen gas, an inert gas such as helium or argon may be present. The reaction is usually carried out by a normal pressure flow method, but if necessary, it can also be carried out under reduced pressure or increased pressure, preferably at 0.1 to 100 kg/cm ² -G. The gas hourly space velocity of methane and oxygen gas in this reaction varies from 30hr -1 to 30hr ^-1 depending on the reaction temperature and desired conversion rate.
It can be determined within the range up to 400000hr ^-1 . Further, in the present invention, the catalyst can be used in any of a fixed bed, fluidized bed, or moving bed mode. By converting methane to ethane or ethylene by the method of the present invention, it can be used as a petrochemical raw material for the production of ethylene oxide, ethylbenzene, ethyl chloride, ethylene dichloride, ethyl alcohol, polyethylene, etc.
It becomes possible to obtain even more final products from these. [Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way. Example 1 A wet pellet of barium carbonate was calcined at 500°C for 1 hour and at 800°C for 2 hours to obtain a catalyst. Grind this into 20 mesh and use this catalyst 2
g was placed in a quartz glass reaction tube and heated to 800 g in an electric furnace.
While heating to
The reaction was carried out by flowing at a rate of 50 ml/min and a total pressure of 1 atm. The obtained product was analyzed by gas chromatography. The results are shown in Table 1. Example 2 The methane, air, and helium mixed gases in Example 1 were mixed at 12.9 ml/min, 1.70 ml/min, and 50 ml/min, respectively.
ml/min, and the reaction was carried out with the total pressure at 1 atm. The results are shown in Table 1. Example 3 The methane, air, and helium mixed gases in Example 1 were mixed at 12.9 ml/min, 1.70 ml/min, and 50 ml/min, respectively.
ml/min, the total pressure was 1 atm, and the reaction temperature was
The temperature was changed to 750°C and the reaction was carried out. The results are shown in Table 1. Example 4 A reaction was carried out by replacing barium carbonate in Example 2 with strontium carbonate. The results are shown in Table 1. Example 5 The barium carbonate in Example 3 was replaced with strontium carbonate, and a reaction was carried out. The results are shown in Table 1. Example 6 A reaction was carried out by changing the barium carbonate in Example 3 to strontium carbonate and changing the reaction temperature to 700°C. The results are shown in Table 1. Example 7 Commercially available barium oxide was crushed into 20 mesh pieces and calcined at 500°C for 1 hour and at 800°C for 2 hours to prepare a catalyst. 2g of this catalyst was placed in a quartz reaction tube, and while heated to 800℃ in an electric furnace, methane and
1.5ml each of air and helium mixed gas
min, 3.75 ml/min, 50 ml/min, and a total pressure of 1 atm for reaction. The results are shown in Table 1. Example 8 The reaction temperature in Example 7 was changed to 750°C and the reaction was carried out. The results are shown in Table 1. Example 9 A reaction was carried out by replacing barium oxide in Example 7 with strontium oxide. Note that strontium oxide was prepared by baking Sr(OH) _{2.8H 2} O at 400° C. for 4 hours. The results are shown in Table 1. Example 10 A reaction was carried out by replacing barium oxide in Example 7 with calcium oxide. The results are shown in Table 1. Example 11 In place of barium carbonate in Example 1, a reaction was carried out using a catalyst prepared by impregnating barium carbonate with 2 mol % of lithium nitrate. The results are shown in Table 1. Example 12 Instead of lithium nitrate in Example 11, a reaction was carried out using a catalyst in which 2 mol % of potassium nitrate was supported on barium carbonate by an impregnation method. The results are shown in Table 1. Example 13 A reaction was carried out by changing the reaction temperature in Example 12 from 800°C to 750°C. The results are shown in Table 1. Example 14 Instead of potassium nitrate in Example 13, a reaction was carried out using a catalyst in which 2 mol % of sodium nitrate was supported on barium carbonate by an impregnation method. The results are shown in Table 1. Example 15 Instead of potassium nitrate in Example 13, a reaction was carried out using a catalyst in which 2 mol % of rubidium nitrate was supported on barium carbonate by an impregnation method. The results are shown in Table 1. Example 16 In place of the barium carbonate in Example 1, a reaction was carried out using strontium carbonate on which 2 mol % of potassium nitrate was supported by an impregnation method as a catalyst. The results are shown in Table 1. Example 17 In place of 2 mol % of potassium nitrate in Example 16, a reaction was carried out using a catalyst in which 10 mol % of rubidium nitrate was supported on barium carbonate by an impregnation method. The results are shown in Table 1. Comparative Example 1 A wet pellet of commercially available zinc oxide was calcined at 500°C for 1 hour and at 750°C for 2 hours to prepare a catalyst. 2g of this catalyst was placed in a quartz glass reaction tube, and while heated to 750℃ in an electric furnace, methane was
Air and helium at 1.5ml/min and 3.75ml/min, respectively.
min, 50 ml/min, total pressure was 1 atm, and the reaction was carried out. The results are shown in Table 1. Comparative Example 2 In Comparative Example 1, the reaction was carried out using zirconia oxide as a catalyst instead of zinc oxide. The results are shown in Table 1. Comparative Example 3 A reaction was carried out by replacing zinc oxide in Comparative Example 1 with silicon oxide. The results are shown in Table 1.

〔Effect of the invention〕

The production method of the present invention has a very high selectivity of methane to ethane and ethylene, and has extremely high industrial value.

Claims (1)

[Claims] 1. When producing hydrocarbons with a carbon number of 2 or more by contacting methane with a catalyst in the presence of oxygen gas,
Consisting of one or more metal compounds selected from calcium carbonate, calcium oxide, barium carbonate, barium oxide, strontium carbonate, and strontium oxide as a catalyst, or one or more of the above metal compounds further containing one or more alkali metals. A method for producing hydrocarbons, characterized by using a catalyst.