JPH09249595A - Production of methanol - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain methanol from carbon monoxide, carbon dioxide and hydrogen under mild conditions in high space velocity and selectivity by using a catalyst comprising palladium prepared from an organic fatty acid palladium salt and a zinc compound. SOLUTION: Carbon monoxide is reacted with carbon dioxide and hydrogen in the presence of a catalyst (preferably having 0.5-10wt.% palladium content) comprising palladium prepared from an organic fatty acid palladium salt (preferably palladium acetate) and a zinc compound (e.g. zinc nitrate). The catalyst is preferably prepared by an impregnation method, e.g. a method dissolving the organic fatty acid palladium salt into a dispersing medium and supporting the compound on the zinc compound. The catalyst is as necessary, preferably subjected to treatments such as baking, reduction, etc. Furthermore, the reaction is preferably carried out at 250-350 deg.C under 40-100atm in 10<3> to 5×10<4> hr<-1> gas space velocity at (1/10) to (10/1) molar ratio of hydrogen/carbon monoxide and carbon dioxide.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing methanol by reacting carbon monoxide and carbon dioxide with hydrogen.

[0002]

2. Description of the Related Art Conventionally, a process for producing methanol from synthesis gas has been performed in the presence of a zinc oxide-chromium oxide catalyst at 300-35.
It was carried out industrially under reaction conditions of 0 atm and 300 to 400 ° C. (German Patent No. 441433). Later, a copper-zinc oxide catalyst was used to produce methanol under reaction conditions of 100 to 200 atm and 200 to 300 ° C., which has been achieved up to now (German Patent No. 2056612). However, since it requires operation at high pressure and high temperature, research into catalysts that are effective at lower pressures and temperatures has been vigorous and it has been found that palladium catalysts produce methanol under mild reaction conditions. As an example of the report, Journal of Catalysis, Vol. 52, p. 157 (1978
, JP-A-56-95136, JP-A-57-209236, Chemistry Letters, page 1249 (1981).
, 1982, February 1982, page 213, etc.

[0003] In these documents, there are few reports that give effective productivity of methanol.
There are many disadvantages. For example, JP-A-55-43003 has a drawback that an expensive catalyst carrier such as lanthanum oxide and neodymium oxide is required. Further, JP-A-56-95137 still requires a high reaction pressure of 150 atm or higher, and there is a lot of room for improvement. On the other hand, an example of using a zinc compound such as zinc oxide, which is easily available and inexpensive, as a catalyst carrier is also available in the Journal of Catalysis 70
Vol. 287 (1981), etc., but sufficient space-time yield of methanol has not been obtained.

[0004]

In view of the above situation, an object of the present invention is to provide a method for producing methanol from carbon monoxide and a synthesis gas containing carbon dioxide and hydrogen under milder reaction conditions. Especially.

[0005]

Means for Solving the Problems As a result of intensive studies for solving the above-mentioned problems, the present inventor has found that carbon monoxide and It has been found that an effective methanol space-time yield and a high selectivity to methanol can be obtained by reacting carbon dioxide with hydrogen, and the present invention has been completed. That is, the present invention is a method for producing methanol, which comprises reacting carbon monoxide and carbon dioxide with hydrogen in the presence of a catalyst composed of a palladium compound prepared from an organic fatty acid palladium salt and a zinc compound.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The methanol synthesis reaction of reacting carbon monoxide and carbon dioxide of the present invention with hydrogen can be represented by the following formula. CO + 2H ₂ → CH ₃ OH CO 2 + 3H ₂ → CH ₃ OH + H ₂ O

Examples of the organic fatty acid palladium salt used for preparing the catalyst of the present invention include Pd (HCOO) ₂ and Pd (C
₂ O ₄ ), Pd (CH ₃ COO) ₂ , [Pd (NH ₃ )
_{4] (CH 3 COO) 2} , [Pd (PPh 3) 2]
(CH ₃ COO) ₂ , Pd (C ₁₇ H ₃₅ COO) ₂ , P
can be exemplified _{d (C 6 H 5 COO)} 2 or the like. Of these organic fatty acid palladium salts, palladium acetate is the cheapest and is industrially advantageously used. Generally, a halide such as palladium chloride is often used for the preparation of a palladium catalyst, but hydrogen chloride or the like is generated during reduction,
Palladium compounds containing halogen elements are not used because they significantly impair the ability to generate methanol. Examples of the zinc compound of the present invention include zinc nitrate, zinc acetate, zinc oxalate, zinc formate, zinc carbonate, basic zinc carbonate, zinc oxide,
Zinc hydroxide, zinc phosphate or the like can be used. The palladium content of the catalyst of the present invention is not particularly limited,
-20 wt%, preferably 0.5-10 wt%.

The method for preparing the catalyst in the present invention is not particularly limited, and various methods such as kneading method, coprecipitation method and impregnation method can be used. For example, a method of wet kneading the palladium compound and the zinc compound, a method of coprecipitating a mixed solution of the palladium compound and the zinc compound with an appropriate precipitant, and the like can be used. However, in order to effectively use palladium, it is most preferable to support it by an impregnation method. In the case of the impregnation method, a method of dissolving a palladium compound in a suitable dispersion medium and supporting it on a zinc compound, a method of co-impregnating a dispersion medium in which a palladium compound and a zinc compound are dissolved into a suitable catalyst carrier, and the like can be used. . Any dispersion medium may be used as long as it has a solubility sufficient to be supported, and water, ammonia water, acetic acid, methanol, acetone, tetrahydrofuran, benzene, or a mixed solution thereof can be used. Also, the catalyst carrier inhibits the production of methanol,
There is no particular limitation as long as it does not show catalytic activity in the secondary reaction of the produced methanol, activated carbon, silica, α-
Alumina or the like can be used.

The shape of the catalyst of the present invention is not particularly limited, and it can be used in the form of powder, coarse particles, tableting pellets, extrusion pellets and the like. It is desirable that the catalyst of the present invention be subjected to treatment such as calcination and reduction, if necessary, before it is used in the reaction. The calcining treatment is preferably performed by standing or flowing in a calcining furnace and treating in the range of 200 to 600 ° C. in air or an inert gas atmosphere. A conventional method can be adopted for the reduction treatment, and reduction with hydrazine, reduction with an aqueous formalin solution, reduction with hydrogen gas, etc. are effective in the range of room temperature to 500 ° C. It can also be reduced by the synthesis gas of methanol synthesis raw material or methanol. The reaction method in the present invention is not particularly limited as long as it is an ordinary reaction method using a solid catalyst, and it can be used for the reaction in a fixed bed, fluidized bed or suspension bed state.

The raw material gas used in the reaction of the present invention is a synthesis gas used in general methanol synthesis and is not particularly limited as long as it contains carbon monoxide, carbon dioxide and hydrogen, and an inert gas, methane. It does not matter even if it includes etc. Generally, those obtained by steam reforming of natural gas, decomposition of naphtha, coal, etc. are used. The molar composition ratio of carbon oxides / hydrogen composed of carbon monoxide and carbon dioxide is in the range of 1/50 to 50/1, and 1/10 to 1: 1.
It is preferably in the range of 0/1. The reaction conditions of hydrogen with carbon monoxide and carbon dioxide are 100 at the reaction temperature.
To 500 ° C., preferably 250 to 350 ° C., reaction pressure 10 to 200 atm, preferably 40 to 100 atm, gas hourly space velocity 10 ² to 10 ⁵ hr ⁻¹ , preferably 10 ^{3 to} 5. It is in the range of 0 × 10 ⁴ hr ⁻¹ .

[0011]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. In each Example and Comparative Example, the following formulas were used to calculate the methanol yield, space-time yield and selectivity. Methanol yield (%) = Methanol production rate (mol / hr) x 10
0 / {Carbon monoxide + carbon dioxide} Supply rate (mol / hr) Methanol space-time yield (g / L-cat · hr) = Methanol production rate (mol / hr) x 32.0 / Catalyst volume (ml) x 1000 Methanol Selectivity (%) = Methanol production rate (mol / hr) ×
100 / {carbon monoxide + carbon dioxide} consumption rate (mol / hr)

Example 1 0.299 g of palladium acetate was impregnated and supported on 5.99 g of commercially available powdered zinc oxide from an acetone solution. The obtained powder is pelletized with a tablet press and then crushed to a particle size of 0.5 to 1.0 mm.
Prepared. This was reduced in a hydrogen stream at 300 ° C. for 3 hours to obtain a 2 wt% palladium-supported zinc oxide catalyst. This catalyst
2.50 g (1.80 mL) was filled in a SUS pressure resistant reaction tube and the reaction temperature was set to 2
75 ° C. and 300 ° C., the reaction pressure 70 kg / cm reactive gas under the conditions of _{^{2 (CO / CO 2 / H}} 2 / CH 4 = 25/5/69 / 1vol%) per hour 10 l
The reaction was carried out by circulating (converted to standard conditions). Gas chromatographic analysis confirmed the production of methanol and methane, and no other products were observed. The results are shown in Table 1.

Example 2 A 5 wt% palladium-supported zinc oxide catalyst was prepared in the same manner as in Example 1 except that 9.60 g of commercially available powdered zinc oxide and 1.06 g of palladium acetate were used. When an activity test was conducted using 2.43 g (1.80 mL) of this catalyst under the same conditions as in Example 1, production of methanol and methane was confirmed, and other products were not observed. The results are shown in Table 1.

Example 3 An activity test was conducted under the same reaction conditions as in Example 1 using 0.86 g (0.65 mL) of the catalyst prepared in Example 1. As a result, formation of methanol and methane was confirmed, and other products were confirmed. Was not recognized. The results are shown in Table 1.

Example 4 When 0.85 g (0.65 mL) of the catalyst prepared in Example 2 was used and an activity test was conducted under the same reaction conditions as in Example 1, production of methanol and methane was confirmed and other products were confirmed. Was not recognized. The results are shown in Table 1.

Example 5 23.4 g of commercially available powdered zinc oxide was impregnated with 0.99 g of palladium acetate from a toluene solution. 400 powder obtained
The mixture was air-calcined at ℃ for 3 hours, pelletized with a tablet molding machine and then pulverized to a particle size of 0.5 to 1.0 mm. This was subjected to reduction treatment in a hydrogen stream at 300 ° C. for 3 hours to obtain a 2 wt% palladium-supported zinc oxide catalyst. When 2.68 g (1.80 mL) of this catalyst was used for the activity test under the same conditions as in Example 1, the production of methanol and methane was confirmed, and no other product was observed. The results are shown in Table 1.

Comparative Example 1 0.31 g of palladium chloride was impregnated and supported on 10.0 g of commercially available powdered zinc oxide from a dilute aqueous hydrochloric acid solution. The obtained powder was treated in the same manner as in Example 1 to obtain a 2 wt% palladium-supported zinc oxide catalyst. When 2.50 g (1.80 mL) of this catalyst was used and an activity test was conducted under the same conditions as in Example 1, formation of methanol was not observed.

Comparative Example 2 0.330 g of palladium chloride was added to 10.0 g of commercially available powdered zinc oxide.
It was impregnated and supported from a 28 wt% aqueous ammonia solution. The obtained powder was treated in the same manner as in Example 1 to obtain a 2 wt% palladium-supported zinc oxide catalyst. When 2.58 g (1.80 mL) of this catalyst was used and an activity test was conducted under the same conditions as in Example 1, the formation of methanol was not observed.

[0019]

[Table 1] Gas Methanol Methanol Reaction temperature Space velocity Yield (space time yield) Selectivity ° C hr ^-1 % (g / L · hr)% Example 1 275 5560 5.83 (131) 98.3 300 5560 14 .7 (331) 98.7 Example 2 275 5560 10.4 (232) 99.2 300 5560 18.1 (404) 98.6 Example 3 275 15400 2.03 (130) 94.0 300 154006 .08 (389) 95.4 Example 4 275 15400 4.58 (295) 97.0 300 15400 9.69 (626) 97.4 Example 5 275 5560 6.16 (138) 98.2 300 5560 15 .1 (338) 98.4

[0020]

According to the present invention, by reacting carbon monoxide and carbon dioxide with hydrogen in the presence of a catalyst composed of palladium and an inexpensive zinc compound, useful methanol can be produced under mild reaction conditions of about 70 atm. It can be obtained with high space-time yield and selectivity.

Claims (2)

[Claims] 1. A method for producing methanol, which comprises reacting carbon monoxide and carbon dioxide with hydrogen in the presence of a catalyst comprising palladium and a zinc compound prepared from an organic fatty acid palladium salt. 2. The method for producing methanol according to claim 1, wherein a catalyst prepared by supporting palladium acetate on a zinc compound is used.