JP2899634B2 - Method for producing ethylene - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing ethylene by reacting ethane with oxygen.

[0002]

2. Description of the Related Art Ethylene is a basic chemical raw material which is a raw material for about 40% of organic chemical products. In order to use ethane, which is a saturated hydrocarbon, as a chemical raw material, it must first be converted to ethylene. In this case, if ethylene can be directly produced by reacting ethane with oxygen, it is convenient and desirable. However, in the reaction between ethane and oxygen, the combustion reaction usually takes precedence and CO ₂ (carbon dioxide)
And CO (carbon monoxide) are formed.

[0003] Heretofore, complex oxides containing V have been reported as catalysts for directly producing ethylene from ethane (Koyasu, PETROTECH, 1994). However, in this method, the ethane concentration in the reaction gas is set to 10% or more,
If the ethane conversion is 1% or more, the selectivity of ethylene becomes 60% or less, which is not suitable for practical use.

[0004]

Therefore, according to the present invention, the ethane concentration in the reaction gas is set to 10% or more (for example, 40%).
Another object of the present invention is to provide a new ethylene production technique in which the selectivity of ethylene exceeds 60% even when the ethane conversion is 1% or more.

[0005]

Means for Solving the Problems The present inventor has conducted research to solve the above-mentioned problems, and as a result, has found that Fe, Mn,
A catalyst in which at least one of Cu and Co (hereinafter, these metals may be collectively referred to as M) is supported on silica (SiO ₂ ) in a small amount, shows high activity in the dehydrogenation of ethane, It has also been found that high activity is maintained for a long time.

The present invention has been completed based on such new findings, and provides the following catalyst for ethylene production and a method for producing ethylene; SiO ₂ and at least one oxide of Fe, Mn, Cu and Co are used as active components, and Fe, Mn, Cu and
And at least one of Co and Si in the range of 1: 1000 to 100
A catalyst for producing ethylene by oxidation of ethane, characterized in that the catalyst is contained at a ratio of 00 (atomic ratio) .

[0007]

[0008] 2. SiO ₂ and Fe, Mn, Cu and C
o at least one oxide as an active ingredient , Fe, M
The ratio of at least one of n, Cu and Co to Si is
A process for producing ethylene, comprising reacting ethane with oxygen in the presence of a catalyst having a ratio of 1: 1000 to 10,000 (atomic ratio) .

[0009]

The reaction for producing ethylene in the present invention is represented by the following formula.

C ₂ H ₆ +1/2 O ₂ → C ₂ H ₄ + H ₂ O

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

I. Catalyst Preparation Method The SiO ₂ -MO _x (x is 1 to 1.5 depending on the valency of the metal) catalyst used in the present invention is obtained by adding a metal M
It can be prepared by impregnating an aqueous solution of at least one of Fe, Mn, Cu and Co with nitrate and oxalate, drying and firing. Alternatively, it can be prepared by dissolving ethyl silicate and an ethoxylated metal (for example, ethoxy iron) in ethanol, adding a small amount of nitric acid, heating, gelling, drying, and firing. Or water glass and metal M
It can also be prepared by mixing an aqueous solution such as nitrate and oxalate, drying and baking. The atomic ratio in the catalyst according to the invention is M (Fe, Mn,
At least one of Cu and Co): Si = 1: 100
0 to about 10,000, more preferably M: Si =
1: About 2,000 to 10,000.

II. Reaction Operation In the present invention, ethylene can be produced by bringing ethane and oxygen into contact with the catalyst in the gas phase.
The reaction system is not particularly limited, and may be, for example, a fixed bed circulation system in which raw material gases (ethane and oxygen) are introduced into a reactor filled with a catalyst to produce ethylene.

The reaction conditions are not particularly limited, but generally the reaction temperature is about 200 ° C. to 800 ° C., more preferably about 350 ° C. to 700 ° C., particularly preferably about 400 ° C. to 600 ° C., and the reaction pressure is The pressure should be near normal pressure. In addition, the flow rate of the raw material gas in the case of producing ethylene by the fixed bed flow method is not particularly limited, but the space velocity (SV) considering the packing density of the catalyst in the reactor is 1000 to 100,000 ml / g · ca.
It is preferably about t / hr, more preferably about 5,000 to 50,000 ml / g · cat / hr. It should be noted that in general, if the space velocity is too high, the conversion of ethane tends to decrease.

The proportions of ethane and oxygen used as raw materials are not particularly limited, but ethane: oxygen = about 50 to 95:50 to 5 and more preferably 70 to 85: It is preferably about 30 to 15, particularly preferably about 80 to 20.

The reaction is preferably carried out in the presence of an inert gas such as nitrogen, He, Ar and the like. When an inert gas is used, the risk of explosion can be avoided, and by controlling the reaction temperature uniformly, it is possible to suppress side reactions that lower ethylene selectivity and prevent rapid deterioration of catalyst activity. The effect is achieved. Nitrogen is preferable as the inert gas from the viewpoint of cost. When using an inert gas, it is preferable to add about the same volume as the total volume of ethane and oxygen.

In the present invention, the catalyst for producing ethylene from ethane is an oxide containing Si and at least one of Fe, Mn, Cu and Co as active components. Normal,
M content is large (for example, Fe / Si = 1/1000 or more)
It is known that Fe takes six coordination in the catalyst. However, when such a catalyst is used for the oxidation reaction of ethane, the complete combustion reaction takes precedence, and almost all of the product is CO _2.
Becomes However, from the measurement results of the visible light absorption spectrum and the electron spin resonance spectrum, the Fe
It was found that four-coordinate Fe atoms were present in the O _x -SiO ₂ catalyst. It is thought that the catalyst of the present invention exhibits high dehydrogenation activity due to the presence of the four-coordinate Fe atom. Also, when Mn, Cu and Co are used, it is presumed that they exhibit high dehydrogenation activity for the same reason. In addition, since silica has a stable structure even at a high temperature, it is considered that high catalytic activity can be maintained for a long time.

[0018]

According to the present invention, when ethane is oxidized in the presence of the catalyst according to the present invention, a high ethylene conversion is exhibited under relatively mild conditions and high-speed reaction conditions, and a high catalytic activity is maintained for a long time. According to the present invention, ethylene can be efficiently produced from ethane.

[0019]

【Example】

Example 1 An Fe—Si based oxide catalyst (Fe: Si =
5: 10000). That is, (C ₂ H ₅ O) ₄ Si
50 g in _{Fe (NO 3) 3 · 9H} 2 O 0.0485 grams water 5
cc, and the liquid temperature was maintained at 60 ° C. Furthermore, concentrated HNO
₃ 0.5 cc was added, the liquid temperature was raised to 80 ° C., and the mixture was stirred for 6 hours. After drying the gelled solution at 120 ° C for 5 hours, 700 ° C
For 3 hours to produce a catalyst according to the present invention.

Next, the catalyst prepared as described above, 0.2
Grams were filled in a quartz glass reaction tube having an inner diameter of 8 mm and set in a flow reactor. Source gas (C ₂ H ₆ : O ₂ : N ₂ = 4
0:10:50) is supplied under normal pressure at SV = 30000 ml / g · cat / hr. Table 1 shows the reaction results of ethane. The product was analyzed by online gas chromatography. The numerical value of the catalyst composition indicates the ratio of Fe / Si in the catalyst.

Examples 2 to 4 and Comparative Examples 1 to 2 According to the method of Example 1, attention was paid so that the ratio (atomic%) of Fe / Fe + Si in the catalyst became a predetermined value.
After preparing the Si-based oxide catalyst, it was used in the oxidation reaction of ethane in the same manner as in Example 1.

[0022]

[Table 1]

As is evident from the results shown in Table 1, as the content of Fe in the catalyst increases, the conversion of ethane itself increases, but the selectivity of the target ethylene gradually decreases. . In particular, when the content ratio of Fe is 0.1.
Above 10 atomic%, the selectivity for ethylene drops rapidly and the selectivity for CO and CO ₂ increases rapidly. On the other hand, the content ratio of Fe is 0.01 to 0.1%.
It is clear that in the range, the conversion and the ethylene selectivity are balanced.

Examples 5 to 8 An SiO2 powder (particle diameter: 0.063 to 0.200 mm) was impregnated with a predetermined amount of an aqueous solution of a metal nitrate and dried by an evaporator.
The catalyst of the present invention was prepared by calcining at 700 ° C. for 3 hours. The metal: silica (atomic ratio) in the catalyst was all 5: 10000 (0.05 atomic% as metal), and the reaction conditions were the same as in Example 1. Table 2 shows the activities of the obtained catalysts.

[0025]

[Table 2]

From the results shown in Table 2, in addition to Fe, M
It is clear that excellent catalytic activity is also exhibited when using n, Cu and Co.

Example 9 To examine the durability of the catalyst of the present invention (Fe: Si = 5: 10000) obtained in Example 5, the mixed raw material gas was subjected to an oxidation reaction in the same manner as in Example 1, After the passage of time, the conversion and the ethylene selectivity were measured. Table 3 shows the results.

[0028]

[Table 3]

From the results shown in Table 3, it is clear that the catalyst for producing ethylene according to the present invention is excellent in durability and maintains high activity for a long period of time.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C07C 11/04 C07B 61/00 300 // C07B 61/00 300 B01J 23/74 311Z (72) Inventor Yoshiko Nakahara Soraku-gun, Kyoto 9-2 Kizugawadai, Kizucho Inside the Research Institute of Innovative Technology for the Earth (72) Inventor Naoki Isao 9-2 Kizugawadai, Kizucho, Kizucho, Soraku-gun, Kyoto Prefecture Examiner in the Institute for Global Environmental Technology Research Eiko Ebihara (56) References JP-A-63-96140 (JP, A) JP-A-9-38490 (JP, A) JP-A-3-44336 (JP, A) (58) Fields studied (Int. . ^6, DB name) B01J 21/00 - 37/36

Claims (2)

(57) [Claims] An active ingredient comprising SiO ₂ and at least one oxide of Fe, Mn, Cu and Co , Fe, Mn,
1: 1000 at least one of Cu and Co and Si
A catalyst for producing ethylene by oxidation of ethane, characterized in that the catalyst is contained at a ratio of from 1 to 10,000 (atomic ratio) . 2. An active ingredient comprising SiO ₂ and at least one oxide of Fe, Mn, Cu and Co ;
The ratio of at least one of Cu and Co to Si is 1:
A process for producing ethylene, comprising reacting ethane with oxygen in the presence of a catalyst having a ratio of 1,000 to 10,000 (atomic ratio) .