JPH0370692B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing olefins from hydrogen and carbon monoxide. Olefins, especially lower olefins, are important substances as petrochemical raw materials. Currently, lower olefins are mainly produced by naphtha cracking, and some are produced as by-products during the production of catalytic cracking gasoline. In other words, the current situation is that almost all raw materials for olefin production rely on petroleum. On the other hand, Japan is poor in petroleum resources, and relies on imports for more than 99% of its oil resources from overseas.Therefore, there is a problem in terms of stable supply of basic raw materials for the petrochemical industry, and the necessity of countermeasures is being discussed. . The present invention enables the production of olefin using coal and natural gas existing in Japan as raw materials, and is intended to meet the above-mentioned problems. (Prior Art) The production of carbon hydrogens by contacting a mixed gas of hydrogen and carbon monoxide with a catalyst at elevated temperature and pressure is known as the so-called fissure method.
This method is known as a hydrocarbon synthesis method using the Tropschule (FT) method. Catalytic hydrogenation of carbon monoxide produces a mixture of paraffins and olefins containing from 1 to 40 carbon atoms, depending on the catalyst used and the reaction conditions applied;
In some cases, oxygen-containing compounds such as alcohols, aldehydes, ketones, esters or fatty acids are also formed. Small amounts of aromatic hydrocarbons are also produced under certain synthetic conditions. A remarkable activity with respect to the hydrogenation of carbon monoxide is shown by the elements of group 8 of the periodic table, especially iron, cobalt, nickel and ruthenium. Even with these elements, the distribution of products and their compositions significantly vary depending on their hydrogenation activity and the degree of secondary reactions due to re-adsorption of α-olefin as a primary product onto the catalyst surface. Make a difference. Nickel-, cobalt-, and ruthenium-based catalysts give mixtures of predominantly unbranched saturated hydrocarbons, while iron-containing catalysts give unsaturated aliphatic compounds, as well as oxygen-containing compounds, especially aliphatic primary alcohols. It is already known that hydrocarbons can be produced. In addition, by conducting the reaction at atmospheric pressure or elevated pressure at a reaction temperature of about 200 to 300°C, we can produce carbon atoms with a carbon number of 20 or more and a hydrocarbon content of 60% by weight.
It is also known that mixtures containing the above can be prepared. (Problems to be solved by the invention) However, when an iron-based catalyst is used, a mixed product rich in unsaturated hydrocarbon components is obtained, but the amount of carbon dioxide and oxygen-containing compounds produced as by-products is large, making it difficult to produce hydrocarbons. Bad sex. On the other hand, ruthenium-based catalysts have several times higher FT reaction activity per metal than iron-based catalysts, but because their hydrogenation activity is also high, there are many saturated hydrocarbon components in the product, and the reaction pressure and temperature are The chain growth probability α value of the Schurtz-Flory law, which is highly dependent and often used as an index in discussing FT reactions, tends to decrease significantly as the reaction temperature increases. For these reasons, it is said to be extremely difficult to selectively obtain a reaction product containing a large amount of _C2 - _C4 lower olefins or _C5 or higher olefin hydrocarbons using a ruthenium-based catalyst. There is. Further, since the iron-based catalyst used in the known method has a low FT reaction activity per metal, the iron content per catalyst is high, and the reaction is carried out at a high reaction temperature. Carbon monoxide forms carbon according to Boudouard equilibrium at high reaction temperatures. This carbon deposition causes deactivation of the catalyst surface and destruction of the catalyst structure, significantly shortening the catalyst life. Furthermore, since the iron content is high, sintering phenomenon occurs significantly, and the practical life of the catalyst is not always satisfactory. The selectivity for olefin formation decreases as the operating time of the catalyst increases, and under the conditions of high carbon monoxide partial pressure and high reaction temperature that favor olefin formation, the catalyst lifetime is limited to several hundred hours. . Furthermore, commonly used carbon monoxide hydrogenation catalysts are sensitive to all kinds of poisonous effects, and the most potent poisonous substances are sulfur compounds, which are said to form inactive metal sulfides on the catalyst surface. For this reason, it is necessary to purify the raw materials carbon monoxide and hydrogen, and there is an urgent need to develop a sulfur-resistant catalyst that takes into account the economic efficiency of the reaction. Furthermore, when producing olefins by hydrogenating carbon monoxide, the reaction activity of the catalyst is significantly influenced by the hydrogen partial pressure, and the higher the hydrogen partial pressure, the higher the conversion rate achieved. However, at the same time, as the hydrogen partial pressure increases, the hydrogenation of the primarily formed olefin also increases, and the olefin selectivity in the product decreases. In addition, H ₂ O + COH ₂ + CO ₂
It is necessary to take into account the decrease in carbon monoxide concentration and increase in hydrogen concentration in the raw material due to side reactions such as. Therefore, it is important that the hydrogenation of carbon monoxide proceeds at a high conversion rate, that the hydrogenation of the primarily produced olefin is suppressed, and that the conversion of carbon monoxide by water vapor is sufficiently inhibited. This is an important issue in increasing the selectivity of olefins. Also, looking at the hydrogenation reaction of carbon monoxide from equilibrium theory, there is a relationship between the free energy change ΔF of hydrocarbon production and the equilibrium constant K as −ΔF=RT1nK, so at a certain temperature, the hydrogenation of carbon monoxide It can be determined whether the chemical reaction is advantageous from an equilibrium point of view. Generally, in the low temperature range, the production of paraffin is more advantageous than the production of olefin. Furthermore, the ethylene/ethane production ratio is smaller than the propylene/propane production ratio, and from an equilibrium point of view it is better to increase the ethylene/ethane production ratio than to increase the propylene/propane production ratio due to the selectivity of the FT reaction product. It can be said that it is more difficult. The selective production of C ₂ to C ₄ lower olefins is disadvantageous in terms of equilibrium theory, but how to overcome this disadvantage kinetically is the key to obtaining lower olefins with good selectivity. . Therefore, there would be great benefits if olefinic hydrocarbons could be produced at high conversion rates and high selectivity by catalytically reacting carbon monoxide with hydrogen. (Means for solving the problem) This time, we demonstrated that a Ru-based catalyst in which an alkali metal and sulfur coexist in manganese oxide exhibits unique behavior in the catalytic reaction (FT reaction) between carbon monoxide and hydrogen. They discovered this and completed the present invention. The main purpose of the present invention is to provide a method for producing olefinic hydrocarbons, especially lower olefins such as _C2 to _C4 , with high selectivity.Another purpose of the present invention is to suppress the production of methane and to produce olefinic hydrocarbons with high selectivity. Another object of the present invention is to provide a method for producing olefin-rich hydrocarbons with a high conversion rate. That is, the gist of the present invention is to provide a method for producing olefins, which comprises producing olefins by bringing a mixed gas containing hydrogen and carbon monoxide into contact with a catalyst made of manganese oxide, an alkali metal, sulfur, and ruthenium. Exists. The catalyst of the present invention has ruthenium supported on manganese oxide and contains alkali metal and sulfur, but may further contain other inorganic metal oxides and activators if necessary.
Alkali metals, sulfur, other inorganic metal oxides, and activators may be mixed with manganese oxide and ruthenium may be supported thereon, or they may be supported on manganese oxide in the same manner as ruthenium. The inorganic metal oxide may be a physical mixture with a catalyst consisting of manganese oxide, an alkali metal, sulfur, or ruthenium. The manganese oxide used for catalyst preparation is subjected to thermal transition by heating in air, or hydrothermal transition, or
Various manganese oxide forms can be obtained by reduction with CO, H ₂ etc., but the manganese oxides used here include MnO ₂ , Mn ₂ O ₃ , Mn ₃ O ₄ , MnO
These oxides can have various crystal structures. For example, MnO ₂ has α, β, γ, δ,
Those with ε-type crystal structure, and Mn ₂ O ₃ have α and γ
type crystal structure is used. In order to enhance the dispersion state of ruthenium as an active metal in the FT reaction and maintain high reactivity, it is advantageous for the surface area of the manganese oxide to be larger. In addition, from the viewpoint of utilizing the redox reaction of manganese oxide, in order to further improve olefin selectivity and catalytic activity, the charge number of manganese should be in a high oxidation state, that is, the charge component of Mn ⁴⁺ or Mn ³⁺ should be more Those containing a large amount (MnO ₂ , Mn ₂ O _3, etc.) are desirable. The method of supporting an alkali metal on manganese oxide used here includes, for example, immersing manganese oxide in a solution of an alkali metal compound and adsorbing it onto the manganese oxide, attaching it by ion exchange, or The manganese oxide and the solution containing the alkali metal compound can be brought into contact with each other to support the manganese oxide, such as by evaporating to dryness or dropping the solution onto the manganese oxide. Further, the alkali metal can be supported before or after the ruthenium is supported, or at the same time as the ruthenium, but preferably the alkali metal is supported before the ruthenium is supported. Examples of alkali metal compounds that can be used in these cases include LiOH, NaOH, KOH, CsOH,
Alkali metal hydroxides such as RbOH or
Alkali metal carbonates such as LiCO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Cs ₂ CO ₃ and Rb ₂ CO ₃ ; inorganic salts such as alkali metal halides and nitrates; and organic salts such as alkali metal acetates. There are various alkali metal compounds such as salts and alcoholates. By adding a predetermined amount of sulfur, which is said to be a powerful catalyst poison, to these manganese oxide-alkali metal systems, we surprisingly succeeded in achieving the results that we had proposed earlier.
Not only can the catalytic properties of _the Ru/γ-MnO ₂ catalyst be further improved, but also it has a long catalyst life and a high It has been found that catalysts with catalytic activity as well as high olefin selectivity can be provided. For example, the catalyst of the present invention has a lifetime about 1.5 to 2.0 times longer than Ru/Mn-based catalysts that do not contain alkali metals and sulfur;
% higher olefin yields. Sulfur can be doped onto the catalyst by various conventionally known methods. For example, it is possible to introduce sulfur directly into the catalyst material in the form of sulfur compounds or to treat the finished catalyst with gaseous sulfur compounds, such as sulfur hydrogen, carbon disulfide or carbonyl sulfide. Any sulfur compound may be used, such as thiocyanates, sulfates, hydrogen sulfates, pyrosulfates, sulfites, hydrogen sulfites, thiosulfates, sulfides, polysulfates, etc. of various metals or ammonium cations. These include sulfides, sulfur-containing hydrocarbons, and sulfuric esters. The alkali metal and sulfur components may be added during or after the preparation of the manganese oxide, or before or after supporting Ru as _an active metal. , CS ₂ , etc., the addition treatment can be performed after catalytic reduction. Either alkali metal and sulfur may be added first, and compounds containing both alkali metal and sulfur components, such as alkali metal sulfides, various sulfur-containing oxyacids, etc. For example, K ₂ SO ₄ , K ₂ S ₂ O ₇ ,
_{K2S , K2S5 , K2SO3} , _{KHSO3 , K2S2O3 ,}
KSCN, KHSO ₄ , etc.) in a suitable solvent,
Alkali metals and sulfur can also be added at the same time. Alternatively, it is also possible to mix a predetermined amount of alkali metal and sulfur during the synthesis of manganese oxide. For example, mixing alkali metals during the electrolytic oxidation synthesis of α-type MnO ₂ or leaving an appropriate amount of alkali metals or sulfate radicals remaining during water washing during the synthesis of γ-type MnO ₂ by air oxidation of manganese carbonate. good. A preferred catalyst of the present invention is one in which ruthenium is supported on a manganese oxide containing a small amount of alkali metal and sulfur. The preferred amount of alkali metal is about 0.01 to 5 wt%, preferably 0.05 to 3 wt%, based on the total weight of the catalyst. If the amount of alkali metal is too large, the catalytic activity will be low, and if it is too small, secondary reactions such as hydrogenation will reduce the selectivity of olefin production. The amount of sulfur added is approximately 0.001 based on the total weight of the catalyst.
~3wt%, and preferably 0.07-1.5wt%. Favorable olefin selectivity cannot be obtained if either the alkali metal or the sulfur component is insufficient in the catalyst having the above composition, and no significant improvement in catalytic activity can be obtained if the amount of either component is too large. Particular attention should be paid to FT of Ruthenium supported on these materials
It is also possible to include other inorganic metal oxides (acting as carrier materials, supports, etc.) in the catalyst that do not substantially inhibit the hydrocarbon synthesis properties. For example, TiO ₂ , SiO ₂ , Al ₂ O ₃ ,
Inorganic metal oxides such as Cr ₂ O ₃ , V ₂ O ₅ , WO ₃ , MoO ₃ , zeolite, etc. can be homogeneously mixed with manganese oxide, mixed with manganese oxide containing alkali metals and sulfur, or mixed with alkali metals and manganese oxides containing sulfur. It can be mixed with sulfur-containing manganese oxide supported on ruthenium, or supported on another carrier. Also applicable is a method in which predetermined amounts of manganese oxide, alkali metal, sulfur, and ruthenium are supported on these inorganic metal oxides. The preferred amount of the above inorganic metal oxide is based on the total weight of the catalyst.
0.01 to 90 wt%, especially about 5 to 60 wt%. These inorganic metal oxides can increase the surface area of the catalyst,
It is effective for increasing mechanical strength or lowering the price of the catalyst. The catalyst of the present invention contains an alkali metal, sulfur, manganese oxide and ruthenium as essential components. The content of ruthenium is approximately 0.1 to 50 wt%, especially approximately 0.1 to 30 wt% based on the total weight of the catalyst.
% (Ru equivalent value) is preferable. If the amount of ruthenium blended is too small, the catalyst activity will be low, and if it is too large, the selectivity for olefin production will be reduced. The majority of ruthenium in the catalyst is usually an elemental metal, but it may also be in the form of a compound such as an oxide. Further, the catalyst may further contain an activator to increase its activity. Examples of the activator include magnesium, zinc, copper, iron, etc., and the activator may be in the form of an elemental metal or a compound such as a chloride, ammonium salt, nitrate, or oxide in the catalyst.
Examples of activator components used as raw materials during catalyst preparation include magnesium chloride, zinc chloride, copper chloride, iron chloride, and iron nitrate. The amount of activator added is approximately 0.01 to 35wt in terms of a single metal based on the total weight of the catalyst.
%, especially about 0.1 to 20 wt%. The preferred total amount of the activator and other inorganic metal oxides is about 0.01 to 90 wt%. These activators may be added during synthesis of manganese oxide or mixed with manganese oxide, but it is preferable to carry them before, after, or simultaneously with ruthenium after synthesis of manganese oxide. If the content of the activator in the catalyst is too large, the content of ruthenium or manganese oxide will be relatively small, resulting in a decrease in catalyst activity and a decrease in selectivity for olefin production. The ruthenium catalyst used in carrying out the process of the invention can be prepared by techniques known in the art for the production of other catalyst systems such as ruthenium on alumina catalyst (Ru/Al ₂ O ₃ ), etc. Manufactured.
Ruthenium can be supported on a mixture of manganese oxide, an alkali metal, and sulfur by, for example, immersing this mixture in a solution of a ruthenium compound and adsorbing it onto the mixture, or depositing it by ion exchange, or by precipitation of an alkali, etc. The ruthenium compound can be supported by bringing the mixture into contact with a solution containing the ruthenium compound, such as by adding an agent to deposit the ruthenium compound, evaporating the solution to dryness, or dropping the solution onto the mixture. Examples of ruthenium compounds that can be used in these cases are water-soluble compounds such as ruthenium chloride, ruthenium nitrate, ruthenium acetate, hexaammonium ruthenium chloride ([Ru(NH ₃ ) ₆ ]Cl ₃ ), or ruthenium carbonyl clusters. and ruthenium acetylacetonate (Ru(C ₅ H ₇ O ₂ ) ₃ ), which are soluble in organic solvents. The product thus obtained is dried in a customary manner, with or without shaping. Drying can be carried out, for example, by holding at room temperature to 300°C for about 10 to 48 hours. The most preferred drying method is about 90~110℃ in air after drying at room temperature.
℃ for several hours, or immediately heated in air to about 90-110℃ for several hours. Ruthenium used in the method of the invention -
Alkali metal-S compound-manganese oxide based catalysts have different product distributions and effects depending on whether or not the catalyst is calcined in air at an elevated temperature before reduction with hydrogen gas and introduction of synthesis gas. The average particle size of the supported ruthenium varies. The higher the firing temperature is, the larger the average particle size of ruthenium becomes, and the distribution of generated hydrocarbons changes, so that more higher hydrocarbon components are generated. _C2 ～ _C4
When the objective is to obtain a lower olefin, it is preferable to omit this in-air calcination treatment and directly lead to the reduction step using H ₂ gas. In this case, the average ruthenium particle diameter is 2 nm or less. If you want to obtain an olefin with higher boiling point components than lower olefins, for example an olefin with 5 to 40 carbon atoms, the temperature should be about 600℃.
Hereinafter, firing is preferably performed at a temperature of about 300 to 600°C.
Preferably, the firing time is about 30 minutes to 24 hours. The calcination may be performed by calcination of only the substrate to be supported before ruthenium is supported, by calcination of the catalyst after ruthenium is supported, or by calcination of the catalyst at the same time as the ruthenium-supported substrate, but the most preferred method is The method is to carry out firing after supporting ruthenium. Calcining only the supporting substrate before supporting ruthenium is also effective because the crystal form of manganese oxide is
This is because changes occur in the number of charges, surface area, etc.
If the calcination is carried out under high temperature conditions exceeding 600°C, the catalyst activity will be reduced and the selectivity for olefin production will be reduced. The ruthenium-supporting substrate used in the practice of the present invention may be in any form, such as powder, granules, or extruded, and has an area of about 1 to 350 ^{m 2} /g, preferably about 10 to 250 m ² /g.
g, most preferably about 50 to 250 m ² /g. There is no limit to the surface area, but in general, a larger surface area is more advantageous. Ruthenium is supported in the catalyst at a concentration of about 0.1-50 wt%, preferably about 0.1-30 wt%, most preferably 0.5-25 wt%. The ruthenium catalyst prepared as described above or by a similar method is heated in a reducing atmosphere such as hydrogen or carbon monoxide to above about 300°C, preferably above about 400°C, before loading with synthesis gas. The heat treatment is preferably carried out at a temperature of about 0.5 to 4 hours. In this case it is preferred to maintain a pressure of about 1 atm atmospheric pressure. When performing reduction treatment with hydrogen, etc., the catalyst surface is treated through a pretreatment process in which water, an oxygen-containing compound such as methanol or ethanol, or hydrogen sulfide, etc. is introduced simultaneously with hydrogen, and this activation and sulfurization treatment is performed. It is also possible to control the distribution of objects. This reduction step or pretreatment step that involves heat treatment does not necessarily need to be carried out as a separate step, since the FT synthesis reaction is carried out in a reducing atmosphere and therefore has the same catalytic reduction effect as the above step. The reaction operating conditions of the method of the invention are typical of FT synthesis. The pressure is between 0 and 100 Kg/cm ² G, preferably between 0 and 30 Kg/cm ² G, most preferably between 0 and 20 Kg/cm ²
It is in the range of G. It may also be carried out under reduced pressure. The temperature is in the range of about 100-500°C, preferably about 200-450°C, most preferably about 250-400°C. The gas mixture has a hydrogen to carbon monoxide molar ratio ( _H2 /CO ratio) of about 0.1 to 10, preferably about 0.5 to 4, most preferably 0.5 to 1, with a slight excess of carbon monoxide. The space velocity (GHSV) of the supply gas is approximately 100hr ^-1 ~ 50000hr ^-1
is within the range of The gas mixture leaving the reaction chamber is fed completely or partially back into the apparatus after removal of the hydrocarbon products produced. The catalyst used in the process of the invention is generally applied in fixed bed form. However, fluidized beds, suspended beds, etc., in which they are used in finely divided form, are also applicable. The catalyst may also be removed from the reaction vessel for continuous or discontinuous regeneration. Regeneration of the catalyst takes place by combustion with air in a special vessel to remove impurities deposited on the catalyst surface and subsequent reduction using known methods. During the reduction step or reaction as pretreatment of the catalyst, most of the ruthenium compound in the catalyst becomes an elemental metal. Furthermore, during the preparation of the catalyst, manganese oxide is thought to change into other crystal forms or other manganese oxides during the reaction. In the catalyst of the present invention, ruthenium and manganese oxide work like a composite catalyst, and the alkali metal and sulfur work like a promoter. (Effects of the Invention) The method of the present invention selectively removes unsaturated hydrocarbons from carbon monoxide and hydrogen by using a catalyst consisting of poorly soluble manganese oxide and ruthenium in which alkali metals and sulfur coexist. to be generated. In particular, gaseous lower olefins are used at reaction pressures of 0 to 5 Kg/cm ² G, and higher unsaturated hydrocarbons are used at elevated temperatures and pressures, using carbon monoxide and hydrogen at about 5 Kg/cm ² G or higher. It can be obtained in good yield by catalytic hydrogenation of carbon monoxide under the following conditions.
In addition, in the method of the present invention, the distribution of the hydrocarbon compounds produced follows the Schurtz-Flory law in the _C3 fraction and above, but in the FT synthesis reaction using ordinary ruthenium catalysts, by-products are unavoidable, and the amount of methane produced is small. Extremely small amounts of unsaturated hydrocarbons of _C2 or higher can be obtained in good yields. Furthermore, in the method of the present invention, olefins with higher boiling points can be produced by changing the firing conditions during catalyst preparation. Furthermore, the catalyst of the present invention has strong sulfur resistance, and raw material gas containing sulfur as an impurity can also be used. (Example) The present invention will be explained below with reference to Examples. In the following examples, the H ₂ /CO molar ratio in the reaction conditions is 1.0 unless otherwise specified.
I did it at Furthermore, unless otherwise specified, commercially available reagents were used for MnO ₂ , MnO, Mn ₂ O ₃ and Mn ₃ O ₄ . γ type and β
A part of the type MnO ₂ was manufactured according to the following reference examples, and when MnO ₂ obtained by the method of these reference examples was used, this is described in the examples. Reference example 1 γ-type manganese dioxide is 1N− with platinum as an anode.
A mixed warm aqueous solution (60° C.) of manganese sulfate (200) and 0.2N sulfuric acid was electrolyzed at a current density of 3.0 A/dm ² to produce electrolytic manganese dioxide on the electrode plate. This was peeled off from the electrode plate, and the adhering electrolyte was thoroughly washed away with warm water. Then further
_NaHCO3 10% solution and as anti-deflocculating agent
Using a 5% NH ₄ Cl solution, stir for 1 hour at a temperature of 60°C and then repeat suction filtration several times to determine the S content in the sample.
It was synthesized by drying in a constant temperature bath at 80-100°C with a concentration of 0.06wt% or less. Reference example 2 β-type manganese dioxide is produced by heating manganese sulfate () hexahydrate in air at 150 to 190°C for 2 to 3 days.
Thereafter, the mixture was washed with boiling dilute nitric acid and then with boiling water, and then reheated at a temperature of 450 to 500°C for synthesis. Example 1, Comparative Example 1 Ru-Na-S/MnO ₂ (catalyst 1) was prepared and evaluated as follows. Commercially available amorphous manganese oxide that does not show a clear diffraction pattern in X-ray diffraction
MnO ₂ (surface area 150.9 m ² /g) was used. 30 g of amorphous MnO ₂ powder was stirred at room temperature all day and night in 80 ml of an aqueous sulfuric acid solution adjusted to pH 4.8. After filtration, drying, and immersion in water (80 ml), a concentrated NaOH aqueous solution was added dropwise to adjust the pH to 9.3. After stirring all day and night, filter it.
Dry in an oven at 90-100°C. Take 22.1 g from the Na-S/MnO ₂ mixture prepared in this way,
It was impregnated in a solution of 2.28 g of ruthenium chloride dissolved in 10 ml of an equal volume mixture of water and ethanol. After standing for a day and night, the solvent was removed under a stream of nitrogen and dried in an oven at 90 to 100°C to obtain catalyst (1). The catalyst (1) prepared in this way contained 0.45% by weight of Na,
It contained 0.26% by weight of S and 4.0% by weight of Ru. 2 ml (2.60 g) of this catalyst was filled into a reaction vessel and subjected to reduction treatment at 400° C. for 2 hours in a hydrogen gas atmosphere. Next, after cooling in hydrogen gas to below the reaction temperature (approximately 100°C), a reaction gas consisting of carbon monoxide and hydrogen (H ₂ /CO
= 1) and supplied it to the catalyst layer as a downward flow to evaluate the catalyst performance. The reaction conditions and product composition are shown in Table-1. For comparison, a method similar to that of the above catalyst (1) was used.
Ru−Na/excluding treatment with H ₂ SO ₄ aqueous solution
MnO ₂ catalyst (3), Ru-S/MnO ₂ catalyst (2) excluding treatment with NaOH aqueous solution, or H ₂ SO ₄ ,
Do not apply any aqueous NaOH treatment
Ru/MnO ₂ catalyst (4) was prepared and evaluated. Table 1 compares and illustrates the olefin selectivity of Ru/Mn-based catalysts depending on the presence or absence of alkali metals and sulfur in the manganese oxide used as a catalyst component. Ru
-Na-S/MnO ₂ -based catalysts produced significantly lower methane than the catalysts lacking either the alkali metal or S content, or both, and the C ₂ fraction. It should be noted that the olefin/paraffin ratio is dramatically improved and the selectivity of _C2 - _C4 lower olefins is particularly high.

【table】

[Table] Example 2, Comparative Example 2 Same as the preparation method of catalyst (1) specified in Example 1
Various manganese oxides with pH adjusted and sulfur content and alkali metal supported [γ-MnO ₂ (surface area of Reference Example 1)
223.1m ² /g), commercially available β-MnO ₂ (large crystallinity, surface area 10.5m ² /g), Mn ₂ O ₃ (surface area 50.3m ² /g)
Reactions were carried out using Ru-supported catalysts 5, 6, 7, and 8 using Mn ₃ O ₄ (surface area 18.3 m ² /g). Table-2
shows the evaluation results of ruthenium/manganese oxide catalysts containing various alkali metals and sulfur on the olefin properties of catalysts in FT synthesis reactions, as differences in the crystal structure of various manganese oxides and the oxidation number of manganese. Compared to catalysts (9), (10), (11), and (12) that do not contain alkali metals and S content shown as comparative examples, the amount of methane produced in the examples according to the present invention is low, and in particular, the amount of C ₂ The olefin/paraffin production ratio and the total C ₂ to _{C 4} production amount in the distillate are improved in any manganese oxide system, and the coexistence of alkali metals and S
It has been found that the Ru/manganese oxide catalyst has an excellent effect on the production of lower olefins.

【table】

[Table] Example 3, Comparative Example 3 Commercially available MnO powder (surface area 11.8 m ² /g) 8 at 550°C
20.0 g of manganese oxide powder calcined in air for 1 hour was treated with H ₂ SO ₄ and NaOH aqueous solution in the same manner as the catalyst (1) shown in Example 1, and the pH was adjusted.
A catalyst (13) supporting ruthenium was prepared and a reaction was carried out. During the above firing, MnO changed from its initial yellow color to gray and gray. This change indicates that some of the MnO has changed to Mn ₂ O ₃ and/or MnO ₂ . Table 3 shows the evaluation results of MnO used as manganese oxide with and without air firing. Catalyst (14) containing neither alkali metal nor S and uncalcined Ru/
Compared to the MnO catalyst (15), the selectivity for _C2 - _C4 lower olefins was significantly improved in the examples according to the present invention, and the manganese powder catalysts (13), (14) in which MnO was air-oxidized No air firing treatment
It should be noted that methane production is significantly lower than that of the Ru/MnO catalyst (15).

【table】

[Table] Example 4, Comparative Example 4 A Ru-K-S/β-MnO ₂ catalyst was prepared as follows. β-MnO ₂ (slightly low crystallinity, surface area 34.9 m ² /g) synthesized by the method of Reference Example 2 was used as the manganese oxide. This β- _MnO2 powder
100 g was immersed in 100 ml of an aqueous solution containing 0.61 g of KSCN, and after stirring at room temperature overnight, the solvent was removed with a water aspirator and dried in an oven at 80 to 100°C. K-S/β-MnO ₂ mixture prepared in this way
A solution prepared by dissolving 0.45 g of ruthenium chloride in 6 ml of an equal volume mixed solution of water and ethanol was added dropwise to 10 g of the solution. After being left at room temperature for a day and night, the solvent was removed under a nitrogen stream and dried in an oven at 90 to 110°C to obtain a catalyst (16). The catalyst (16) prepared in this way was
It contained 0.24% by weight of K, 0.2% by weight of S, and 2.0% by weight of Ru. Instead of KSCN as K-S covalent compound
A catalyst (17) in which potassium and sulfur were simultaneously supported was prepared in the same manner as catalyst (16) except that K ₂ SO ₄ was used. A reaction was carried out in the same manner as in Example 1 using these catalysts. The reaction conditions and results are shown below.
4. The results in Table 4 show that adding a compound containing both an alkali metal and a sulfur component to manganese oxide can significantly suppress methane production and improve _C2 to _C4 lower olefin selectivity. admitted.

【table】

[Table] Example 5 γ prepared by the synthesis method shown in Reference Example 1 above
12 g of type MnO ₂ (however, the proportion is different from the γ type MnO ₂ used in Example 2, surface area 196 m ² /g) was
It was immersed in 80 ml of the sulfuric acid aqueous solution prepared in 3.9 and stirred at room temperature for 15 hours. After washing with water and drying, KCl0.51g
immersed in 12 ml of an aqueous solution containing After leaving it for a day and night,
The solvent was removed with a water-aspirator and dried in an oven at 90-110°C. K-S/ prepared in this way
Ru-K obtained by impregnating and supporting ruthenium chloride in a γ-MnO ₂ mixed system in the same manner as shown in Example 1.
-S/γ-MnO ₂ was used as the catalyst (19). A catalyst (20) in which the anion of the alkali metal salt was changed was prepared in the same manner as catalyst (19) except that KNO ₃ was used instead of KCl. A reaction was carried out in the same manner as in Example 1 using these catalysts. The reaction conditions and results are shown in Table-5. From the results in Table 5, even if the anion of the alkali metal salt as the alkali metal source was changed, the distribution of the reaction product or the olefin selectivity was hardly affected, and the selectivity was shown in Example 1. This appears as a synergistic effect of the coexistence of alkali metals and sulfur.

【table】

[Table] Example 6, Comparative Example 5 Using commercially available amorphous MnO ₂ (surface area 150.9 m ² /g), the catalyst shown in Example 1 except that the addition treatment of sulfur content with an aqueous H ₂ SO ₄ solution was removed. Ru-Na/MnO ₂ catalyst (22) was prepared in the same manner as in (1),
The reaction was carried out. After carrying out the reaction under predetermined reaction conditions, inject 5 H ₂ S gas into the reaction gas using a syringe.
Table 6 shows the results of a reaction using a catalyst (21) in which a portion of the catalyst surface was poisoned with H ₂ S using a pulse injection method of 9 ml each. Doping of sulfur onto the catalyst can be done in various ways. A catalyst (21) obtained by directly introducing the gaseous sulfur compound exemplified here together with the reaction gas, or a sulfur component directly introduced into the catalyst in the form of sulfate groups or SCN ions during catalyst preparation. Also by catalyst (see Examples 1 to 5),
Conversion rates, product distributions, or olefin selectivities are nearly identical. Therefore, the method of introducing a gaseous sulfur compound into the reaction system as in this example can be said to be a convenient method for preparing the catalyst. As shown in Table 6, compared to the catalyst (22) before the addition of H ₂ S, the catalyst (21) of this example has a higher selectivity for C ₂ to _{C 4} lower olefins, especially for olefins/C ₂ fractions. The paraffin ratio is significantly improved. In addition, the catalyst of the present invention is Ru/
γ-Al ₂ O ₃ catalyst (24) (catalyst (24) with H ₂ S gas 5
The catalyst (23) is sulfurized 4 times in a total of 20 ml, and the CO conversion rate of this catalyst decreases. It should be noted that it has superior sulfur resistance compared to ), and that the sulfurization treatment improves the selectivity of olefins.

【table】

[Table] Example 7, Comparative Example 6 γ type prepared by the synthesis method shown in Reference Example 1
MnO ₂ (surface area, 223.1 m ² /g) was immersed in 80 ml of a sulfuric acid aqueous solution adjusted to pH 5.2, and stirred at room temperature for 25 hours. After drying, immerse in water (80ml), and then
NaOH aqueous solution was added dropwise to adjust the pH to 8.5. In the thus prepared Na-S/γ-MnO ₂ mixed system, ruthenium chloride was dissolved in a mixture of equal amounts of water and ethanol, and 1 wt % of the metal was supported based on the weight of the catalyst. After desolventizing and drying in an oven, heat in an electric furnace for 450 min.
Catalyst (25) calcined at ℃ for 24 hours was charged into a reactor in the same manner as in Example 1, and subjected to reduction treatment to carry out a reaction. The reaction conditions, product distribution, and composition are specified in Table-7. By carrying out air calcination treatment after supporting ruthenium, the product distribution changes significantly compared to the result of catalyst (5) of Example 2, which is advantageous for producing high boiling point fractions. Although the product distribution follows the Schultz-Flory law, compared to the Ru/γ-Al ₂ O ₃ catalyst (26) (calcined at 450°C for 24 hours), the olefin/paraffin content in the product is higher. High production ratio. In addition, the α-olefin content in the produced olefin composition is
90% or more, and it was found that it is advantageous for olefin selectivity, particularly for producing higher α-olefins, under conditions of high temperature and high pressure.

【table】

【table】

【table】

Claims (1)

[Claims] 1. A method for producing olefins, which comprises producing olefins by bringing a mixed gas containing hydrogen and carbon monoxide into contact with a catalyst made of manganese oxide, an alkali metal, sulfur, and ruthenium.