JPS6234737B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention is a method for converting a mixed gas of carbon monoxide and hydrogen (hereinafter referred to as synthesis gas) into a compound having two carbon atoms such as ethanol, acetaldehyde, and acetic acid in the presence of a catalyst.
The present invention relates to a method for directly producing an oxygen-containing compound (hereinafter referred to as a C ₂ oxygen-containing compound). (Conventional technology) Ethanol, acetaldehyde, acetic acid, etc.
C ₂ oxygen-containing compounds are useful industrial products, and it is desired to establish a method for efficiently producing them from coal-based synthesis gas. It is known that rhodium-based composite catalysts exhibit relatively good performance in these productions. For example, a method for producing C2 oxygen _- containing compounds using a rhodium catalyst is published in JP-A-51-80806, a method for producing ethanol using a rhodium-iron catalyst is published in JP-A-51-80807, and a method for producing C2 oxygen-containing compounds using a rhodium-manganese catalyst is published in JP-A No. _2The method for producing oxygen-containing compounds was published in Japanese Patent Application Laid-Open No. 52-14706.
A method for producing acetic acid using a rhodium-ruthenium catalyst is published in U.S. Patent No. 4101450, a method for producing _C2 oxygen-containing compounds using a rhodium-halogen-magnesium catalyst is published in JP-A-54-138054, and rhodium-oxidized A method for producing ethanol using a zirconium-silica catalyst is disclosed in JP-A-56-147730. On the other hand, many studies have been conducted on methods using rhodium-free catalysts for directly producing oxygen-containing compounds from synthesis gas. For example, using an iron-based catalyst, a pressure of 8 to 25 atmospheres, 190 to 225
The dino method produces alcohols by reacting synthesis gas at a high space velocity at a temperature of 10 to 30 atmospheres, a temperature of 180 to 210 degrees Celsius, and 100 to 500 hours using an iron catalyst with a large amount of alkali metal added. The oxyl process, which is used at a gas hourly space velocity of ^-1 and is combined with the oxo process to produce alcohols, has been known for a long time. Recently, a methanol synthesis method using a zinc oxide-copper oxide catalyst has also been implemented industrially. (Problems to be Solved by the Invention) However, rhodium contained in the rhodium-based composite catalyst is an essential active element for the production of C ₂ oxygen-containing compounds. However, rhodium is produced in small amounts and is expensive, which is a major drawback of these manufacturing methods. Therefore, there is a strong need for a method for producing C ₂ oxygen-containing compounds without using rhodium, especially for the development of a catalyst. In addition, the products obtained by the dinol method or oxyl method using a rhodium-free catalyst as described above are mixtures of alcohols having a wide range of chain lengths ranging from 1 to 18 carbon atoms, and are poor in selectivity.
Furthermore, in the methanol synthesis method, the product is limited to methanol, and high-value ethanol is not produced. Furthermore, in the method described above, the production of organic acids such as acetic acid has not been observed. (Means for Solving the Problems) In order to solve the problems found in the conventional methods as described above, the present inventors developed a non-rhodium-based catalyst for selectively synthesizing _C2 oxygen-containing compounds from synthesis gas. As a result of extensive research, we have completed the present invention. That is, the present invention provides a method for directly producing an oxygen-containing compound having 2 carbon atoms by a reaction between carbon monoxide and hydrogen, and in which iridium and at least one member selected from cobalt and nickel are used as catalytic active components.
characterized by using a catalyst containing a species element.
By using a method for producing a _C2 oxygen-containing compound and a three-component catalyst in which lithium is added to an iridium-cobalt two-component catalyst,
This is a method for producing C ₂ oxygen-containing compounds from synthesis gas with good selectivity. The fact that the selectivity for C ₂ oxygenates is significantly enhanced in the binary or ternary catalysts described above is indeed unexpected. In general, iridium is known as a low-activity methanol synthesis catalyst, cobalt as a non-selective hydrocarbon synthesis catalyst, and nickel as a methane synthesis catalyst, while lithium has no catalytic ability for synthesis gas reactions. This is because it was thought that it did not indicate The present invention will be explained in detail below. As mentioned above, the catalyst of the present invention is a two-component catalyst combining iridium and cobalt or nickel;
Alternatively, the iridium-cobalt two-component catalyst is further combined with lithium to form a three-component catalyst. Although the true catalytic active species under the reaction conditions are not necessarily clear, the core of the activity is essentially the metal species that coexist with each other.
Therefore, in principle, there are no restrictions on the form of the catalyst itself or the form of each component in the catalyst. However, iridium and cobalt or nickel are substantially physically mixed or chemically combined with each other as metals or low-valent compounds. Although the catalyst used in the present invention may be used without a carrier, it is preferably supported on a porous material in order to increase the active surface area. As the carrier, oxides of metals in Group 1 of the periodic table are used, and silica is preferred. These carriers can be used in any form such as powder or pellet. The catalyst of the present invention is preferably produced by impregnating a carrier with a solution of an iridium compound and a cobalt compound or a nickel compound, optionally a lithium compound, and then drying. At that time, these metal compounds can be supported simultaneously or sequentially. As the metal compound,
All soluble compounds can be used, such as nitrates, halides, organic acid salts, ammonium salts, clusters, etc., and their types are not particularly limited. These compounds are dissolved in a suitable solvent. Any solvent can be used as long as it dissolves the above metal compound. In addition to the impregnation method, supporting methods include ion exchange method, precipitation method,
A kneading method etc. can also be used. After drying, the catalyst obtained as described above is subjected to a reduction treatment using a suitable reducing agent such as hydrogen.
In this case, the reduction temperature is suitably in the range of 200 to 600°C. Further, prior to the reduction treatment, a firing treatment may be performed using an oxidizing gas such as air, and the temperature at that time is suitably in the range of 200 to 600°C. In the catalyst of the present invention, there are no strict restrictions on the amount of each catalyst component used, but when preparing a supported catalyst, the iridium content should be 0.01 to 15% by weight, preferably 0.1 to 10% by weight. , the contents of cobalt, nickel, and lithium, which are other catalyst components, are expressed as molar ratios to iridium, respectively:
0.001-100, preferably 0.1-10, 0.01-100, preferably 0.1-10, and 0.01-100, preferably
A range of 0.05 to 20 is used. The reaction in the method for producing a C ₂ oxygen-containing compound of the present invention is usually carried out in the gas phase, for example, by passing synthesis gas through a fixed bed reactor packed with a catalyst. In this case, in addition to carbon monoxide and hydrogen, the synthesis gas contains
For example, other components such as carbon dioxide, nitrogen, argon, helium, water vapor, and methane may be included. In addition, the catalyst component device is not limited to the fixed bed type.
Other configurations, such as a moving bed type or a fluidized bed type, may also be used. In some cases, a liquid phase reaction may also be carried out in which the catalyst is suspended in a suitable solvent and a synthesis gas is passed therethrough. Although reaction conditions can be varied within a wide range,
The molar ratio of carbon monoxide and hydrogen is 30:1 to 1:30,
Preferably 10:1 to 1:10, reaction temperature 100 to 500
℃, preferably 150~350℃, pressure 1~
Appropriately is 300 atm, preferably 10 to 200 atm, and a gas hourly space velocity of 10 to 100,000 h ^-1 , preferably about 100 to 10,000 h ^-1 . (Effects of the Invention) According to the present invention, a C ₂ oxygen-containing compound can be directly produced with good selectivity from synthesis gas without using rhodium. (Examples) Next, the present invention will be described in more detail based on Examples, but it goes without saying that the present invention is not limited to these Examples. The meanings of terms in each table of Examples are as follows. CO reaction rate = (A-B)/A A: Number of moles of carbon monoxide supplied B: Number of moles of recovered carbon monoxide Selectivity = C x D/(A-B) C: Moles of the product Number D: Number of carbon atoms in the product A, B: Same meaning as above. Further, each symbol shown in the following examples means each of the following substances. EtOH: ethanol, AcH: acetaldehyde, AcOH: acetic acid, MeOH: methanol,
PrCH: Propanol, _CH4 : Methane, _C2 ⁺ : Total of hydrocarbons having 2 to 5 carbon atoms, _CO2 : Carbon dioxide, _ΣC2 -O: Total of oxygen-containing compounds having 2 carbon atoms Example 1 Tetrachloride Contains 0.528g _of iridium ( _IrCl4.H2O ) and _0.357g of cobalt chloride ( _CoCl2.6H2O )
Transfer 16.5ml of the aqueous solution to Fuji Davison silica gel (#57, 20-32 mesh, hereinafter referred to as silica).
It was impregnated with 15.0g. After standing for 1 hour, it was dried under reduced pressure using an evaporator at 80°C for 1 hour and at 110°C for 1 hour. Next, reduction was carried out at 500° C. for 3 hours in a hydrogen stream to prepare an iridium-cobalt catalyst supported on silica. The amount of iridium and cobalt supported is
Each amount is 100 μmol per 1 g of silica.
1.11 g of the catalyst thus prepared was charged into a high-pressure flow reactor, and 6 Nl/synthesis gas (carbon monoxide/hydrogen molar ratio = 0.5) at a pressure of 50 atm was charged at 280°C.
The reaction was carried out at a flow rate of h. The results are shown in Table 1 as Example 1. Comparative Examples 1 and 2 Aqueous solution containing 0.704 g of iridium tetrachloride
11.0 ml was impregnated with 10.0 g of silica. Thereafter, a silica-supported iridium catalyst was prepared in the same manner as in Example 1. The amount of iridium supported on this catalyst is 1
The amount is 200 μmol per g of silica. Table 1 shows the results of a reaction with synthesis gas under the same conditions as in Example 1 except for using this catalyst as Comparative Example 1. Cobalt chloride instead of iridium tetrachloride
A silica-supported cobalt catalyst was prepared in the same manner as in Comparative Example 1 except that 0.476 g was used. The amount of cobalt supported in this catalyst is per 1 g of silica.
It is 200 μmol. The reaction was carried out under the same conditions as in Example 1 except that this catalyst was used, and the results are shown in Table 1 as Comparative Example 2. As is clear from the comparison between Example 1 and Comparative Example 1 or Comparative Example 2, the activity of the iridium catalyst is extremely low and no C ₂ oxygen-containing compounds are produced, and the activity of the cobalt catalyst is also low and no C ₂ oxygen-containing compounds are produced. The selectivity of is extremely low at 1.6%. However, using an iridium-cobalt catalyst in which iridium and cobalt coexist improves the CO reaction rate and
It can be seen that the activity and selectivity of C ₂ oxygen-containing compounds containing ethanol as a main component are significantly improved.

[Table] Examples 2 to 5 In Example 1, four types of iridium-cobalt catalysts supported on silica were prepared so that the total amount of iridium and cobalt supported was 200 μmol per 1 g of silica.
Example 1
The results of reacting synthesis gas in the same manner as above are shown in Table 2 as Examples 2, 3, 4, and 5. As is clear from the results of Example 2, when the proportion of iridium is high, the selectivity of C ₂ oxygen-containing compounds is further improved, reaching 35%.

[Table] Example 6 10.0 g of a silica-supported iridium-cobalt catalyst prepared in the same manner as in Example 3 was impregnated with 11.0 ml of an aqueous solution containing 0.042 g of lithium chloride (LiCl). Hereinafter, as Example 6, the results were obtained by preparing a silica-supported iridium-cobalt-lithium catalyst by the same operation as in Example 1, and reacting synthesis gas under the same conditions as in Example 1, except that this catalyst was used. It is shown in Table 3. In the catalyst used here,
The supported amount of iridium, cobalt, and lithium is 1g.
150, 50, and 100 μmol of silica, respectively. From the results in Table 3, it is clear that the production activity of C ₂ oxygen-containing compounds is improved by adding lithium to the catalyst.

[Table] Example 7 16.5 ml of an aqueous solution containing 0.924 g of iridium tetrachloride and 0.089 g of nickel chloride (NiCl ₂ 6H ₂ O)
was impregnated into 15.0 g of silica. After leaving it for 1 hour,
1 hour at 80℃ under reduced pressure using an evaporator.
It was dried at 110°C for 1 hour. Then 500 in hydrogen stream
A silica-supported iridium-nickel catalyst was prepared by reduction at ℃ for 3 hours. The amounts of iridium and nickel supported in the catalyst are 175 and 25 μmol, respectively, per 1 g of silica. 1.11 g of the catalyst prepared in this way was charged into a high-pressure flow reactor,
Synthesis gas (carbon monoxide/hydrogen molar ratio = 0.5) at a pressure of 50 atm was flowed at 300° C. at a flow rate of 6 Nl/h to cause a reaction. The results are shown in Table 4 as Example 7. Examples 8 to 10 Three types of iridium-nickel catalysts supported on silica were prepared in the same manner as in Example 7 so that the total amount of iridium and nickel supported was 200 μmol per 1 g of silica, and the experiments were carried out using these. Example 8 shows the results of reacting synthesis gas in the same manner as Example 7.
9 and 10 in Table 4. Comparative Examples 3 and 4 Aqueous solution containing 0.74 g of iridium tetrachloride 11.0
ml was impregnated into 10.0 g of silica. Below, Example 7
A silica-supported iridium catalyst was prepared in the same manner as in Example 7, and the results were shown in Table 4 as Comparative Example 3.
The amount of iridium supported is 200μ per 1g of silica.
It is mol. 0.475g instead of iridium tetrachloride
A silica-supported nickel catalyst was prepared by carrying out the same operation as in Comparative Example 3 except that nickel chloride was used.
The results of the reaction under similar conditions are shown in Table 4 as Comparative Example 4. The amount of nickel supported on this catalyst is 1g
of silica is 200μmol. As is clear from the results in Table 4, in the iridium-nickel catalyst in which iridium and nickel coexist, the activity and selectivity of _C2 oxygen-containing compounds are significantly enhanced.

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Claims (1)

[Claims] 1. By the reaction of carbon monoxide and hydrogen, the number of carbon atoms is 2.
A method for producing a C ₂ oxygen-containing compound, which comprises using a catalyst containing iridium and cobalt, nickel, or both elements as catalyst active components in the direct production of the oxygen-containing compound. 2. The method for producing a _C2 oxygen-containing compound according to claim 1, wherein the catalyst carrier is silica. 3 Due to the reaction between carbon monoxide and hydrogen, the number of carbon atoms is reduced to 2.
A method for producing a C ₂ oxygen-containing compound, which comprises using a catalyst containing iridium, cobalt, and lithium as catalyst active components in the direct production of the oxygen-containing compound. 4. The method for producing a _C2 oxygen-containing compound according to claim 3, wherein the catalyst carrier is silica.