JP3553710B2 - Method for producing methanol - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a novel method for producing methanol. Methanol is an inexpensive and highly versatile useful compound as an intermediate material for various chemical products and as a solvent itself, a fuel for automobiles, and a fuel for thermal power generation.
[0002]
[Prior art]
A method for producing methanol from carbon monoxide and hydrogen has been industrially practiced for a long time. For example, in 1913, the possibility of producing an oxygen-containing compound containing methanol from water gas at a temperature of 300 ° C. or more and 100 atm or more using a catalyst containing oxides such as Cr and Zn as main components by BASF, Germany. After that, so-called high-pressure methanol production methods were started in various countries. In 1959, the company ICI of the United Kingdom made use of CuO-based catalysts at a lower temperature and lower pressure, that is, 200-300 ° C., 50 A process for producing so-called low-pressure methanol in which the reaction is carried out at a pressure of ~ 150 atm has been developed. Since then, catalysts and processes have been improved. At present, most of the industrial production methods of methanol use a copper-based catalyst and are carried out by a low pressure method at a reaction temperature of 200 ° C. and a reaction pressure of about 100 atm.
[0003]
The reaction of methanol synthesis from carbon monoxide and hydrogen is an exothermic reaction as shown in the following equation.
CO + 2H ₂ → CH ₃ OH ΔH ₂₉₈ = -21.7 kcal / mol
Therefore, the lower the temperature and the higher the reaction conditions, the more advantageous for methanol synthesis. Higher activity catalysts at lower temperatures significantly improve the conversion rate of the raw gas, eliminating the need to recycle unreacted gas to the reaction system, and at a lower pressure than the synthesis gas production process. A catalyst exhibiting high methanol production activity is industrially extremely advantageous in that it does not need to be pressurized when introducing a raw material synthesis gas into a methanol reactor.
[0004]
Some catalysts have been known as low-temperature / low-pressure active catalysts having a certain degree of activity under low-temperature and low-pressure conditions, for example, at 160 ° C. or less and 50 atm or less. Among them, a copper or nickel catalyst is known as a highly active catalyst. However, it is known that when a nickel catalyst is used, extremely toxic nickel carbonyl is generated, and handling thereof is extremely difficult. For example, JP-B-63-51130 discloses a method of synthesizing an oxygen-containing organic compound by reacting carbon monoxide and hydrogen with a copper compound other than copper oxide using sodium alkoxide or potassium alkoxide as a catalyst. Is disclosed.
[0005]
For example, in Japanese Patent Publication No. 6-2686 (WO86 / 03190), in the presence of a copper catalyst prepared by the Adkin method and a catalyst comprising an alkali metal alkoxide, the liquid reaction medium in the reactor is added to methanol and methyl formate, A method is disclosed for producing methanol from carbon monoxide and hydrogen in a liquid phase using at least 50% by volume of a non-polar organic solvent having a lower dielectric constant than that of pure methanol at the same temperature.
[0006]
In addition, Appl. Catal. , 103, 105-122 (1993), when a copper chromite catalyst and potassium methoxide (or sodium methoxide) are used in methanol synthesis using carbon monoxide and hydrogen, the reaction temperature is about 100 ° C. as compared with the conventional method. And the amount of recycled gas is reported to be significantly reduced.
[0007]
Further, for example, U.S. Pat. Nos. 4,992,480 and 4,935,395 disclose a carbonyl compound and alkoxide of a metal selected from Cu, Ni, Pd, Co, Ru, Mo and Fe. A method for producing methanol from synthesis gas using a homogeneous catalyst as a catalyst is disclosed.
[0008]
[Problems to be solved by the invention]
As far as the present inventors have verified, none of the catalysts has sufficient activity, and furthermore, there is a problem that the activity is severely degraded, or particularly, carbonyl compounds and the like are difficult to handle. And it is still insufficient for industrial implementation. Therefore, at present, there is a strong desire for a catalyst having higher activity under low-temperature and low-pressure reaction conditions.
[0009]
An object of the present invention is to provide a novel production method using a highly active catalyst for producing methanol from carbon monoxide and hydrogen under low-temperature, low-pressure reaction conditions.
[0010]
[Means for Solving the Problems]
The present inventors have intensively studied industrially advantageous catalysts capable of obtaining high activity at a low temperature of 160 ° C. or lower and a low pressure of 50 atm or lower.As a result, by allowing a platinum group metal to coexist in a catalyst containing a copper compound, The inventors have found that methanol is produced with higher activity, and have completed the present invention.
[0011]
That is, in the present invention, in producing an oxygen-containing compound from carbon monoxide and hydrogen in the presence of a solvent, (1) a divalent copper compound, (2) palladium halide, palladium oxide, palladium cyanide, palladium acetate, A catalyst comprising at least one platinum group metal compound selected from palladium sulfate, palladium nitrate, platinum halide, platinum oxide, platinum cyanide, platinum sulfate, platinum nitrate and (3) metal alkoxide is used. Is a method for producing methanol.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
[0013]
Specific examples of the divalent copper compound used in the method of the present invention include copper (II) chloride, copper (II) bromide, copper (II) iodide, copper sulfate, copper sulfamate, and phosphoric acid. Inorganic copper salts derived from mineral acids such as hydrogen halide, sulfuric acid and phosphoric acid such as copper and copper carbonate; copper (II) acetate, copper (II) formate, copper (II) oxalate and olein Copper carboxylate such as copper (II) acid, copper (II) stearate, copper (II) naphthenate, copper (II) benzoate, copper (II) citrate, copper (II) tartrate and the like. In addition, copper acetylacetonate (II), copper alkoxide (II), copper cyanide (II), and copper (II) thiocyanate can also be used. However, the use of other than these copper compounds does not limit the present invention.
[0014]
When these divalent copper compounds are used as a catalyst, copper (II) chloride and copper bromide (II), which are divalent copper compounds derived from mineral acids such as hydrochloric acid, hydrobromic acid and sulfuric acid, among others, ), Copper (II) sulfate and the like.
[0015]
In the method of the present invention, the amount of the copper compound used is appropriately determined based on the amount of the solvent used. A small amount of the copper compound is sufficient, but if it is too large, the activity is rather reduced. Therefore, the amount of the copper compound used is in the range of 0.5 to 30 wt%, preferably 1 to 30 wt%, based on the solvent.
[0016]
The platinum group compound used in the method of the present invention, specifically, palladium chloride, palladium bromide, palladium halides such as palladium iodide, palladium oxide, palladium cyanide, palladium sulfate, palladium nitrate and the like In addition to the palladium compound, platinum halides such as platinum chloride, platinum bromide and platinum iodide, platinum compounds such as platinum oxide, platinum cyanide, platinum sulfate and platinum nitrate can be mentioned. Among these platinum group metal compounds, hydrochloric acid, hydrobromic acid, compounds of palladium and platinum derived from mineral acids such as sulfuric acid, that is, palladium chloride, palladium bromide, palladium sulfate, platinum chloride, platinum bromide, Platinum sulfate and the like are preferred. However, the use of a platinum compound as a palladium compound other than these does not limit the present invention.
[0017]
The amount of the platinum group compound used in the method of the present invention is appropriately determined by the number of moles of the platinum group metal relative to the number of moles of copper in the copper compound. It is sufficient to use a small amount of the platinum group metal compound, but if it is too large, the activity is rather reduced. Therefore, the amount of the platinum group metal compound used is in the range of 0.1 to 300 wt%, preferably 0.3% by weight, as the number of moles of the platinum group metal in the platinum group metal compound with respect to the number of moles of copper in the copper compound. -30% by weight.
[0018]
The metal alkoxide used in the present invention is an alkoxide of at least one metal selected from Li, Na, and K. Among them, Na and K are preferable as the metal. Alkoxides having 1 to 10 carbon atoms are used. Among them, methoxide, ethoxide, propoxide and butoxide derived from alcohol are preferred, and methoxide is particularly preferred.
[0019]
In the method of the present invention, the amount of the metal alkoxide used is appropriately determined based on the amount of the copper compound used. If the amount of the metal alkoxide is too small, a sufficient catalytic effect cannot be obtained, and if the amount is too large, the reaction is inhibited, which is not preferable. Therefore, the amount of the metal alkoxide used is in the range of 0.1 to 30 times, preferably 0.3 to 10 times the weight of the copper compound.
[0020]
The solvent used in the present invention is not particularly limited, but ethers such as dioxane, tetrahydrofuran, diethyl ether and diphenyl ether, glymes such as glyme, diglyme and triglyme, esters such as methyl acetate and ethyl propionate. , Alcohols having 6 or more carbon atoms such as hexanol and heptanol, hydrocarbons such as hexane, benzene, decalin and chlorobenzene, and halogenated hydrocarbons are preferably used. Also, aprotic polar solvents such as dimethylformamide and N-methylpyrrolidone can be used. Among them, ethers and glymes are particularly preferred.
[0021]
The (1) divalent copper compound, (2) platinum group metal compound and (3) metal alkoxide used in the method of the present invention can be used by mixing them in advance, or they can be used as they are by being sequentially charged into a solvent. This is effective as a catalyst for synthesizing methanol, and any method can be used.
[0022]
In the present invention, a catalyst having excellent methanol activity even at a low temperature of 160 ° C. or less is used, but the reaction can be carried out in a temperature range of 40 to 200 ° C. If the reaction temperature exceeds 200 ° C., the conversion will be significantly reduced. On the other hand, if the reaction temperature is lower than 40 ° C., the reaction rate is small and not practical. Preferably, it is in the range of 60 to 180 ° C. More preferably, it is in the range of 80 to 160 ° C. However, the method of the present invention is not limited to a higher temperature in consideration of overall economic efficiency including recovery of reaction heat and the like.
[0023]
Although the raw material carbon monoxide and hydrogen can be used even if they contain nitrogen or carbon dioxide, it is preferable that the amount of carbon dioxide is small. In some cases, it is desirable to remove trace amounts of sulfur compounds and water before starting the methanol synthesis reaction. The mixing ratio of carbon monoxide and hydrogen is in the range of 1: 0.5 to 1: 5. If the amount of hydrogen used for carbon monoxide is larger than the stoichiometric ratio of 2, the selectivity of methanol is improved, but if it is further increased, excess hydrogen remains unused and is uneconomical. Therefore, the range of 1: 1.5 to 1: 2.5 is practically preferable.
[0024]
In the method of the present invention, the higher the reaction pressure, the higher the methanol activity. However, a practical pressure for supplying the synthesis gas to the reactor without increasing the pressure is preferably 50 kg / cm ² -G or less. However, implementation at higher pressures is also within the scope of the present invention.
[0025]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples.
[0026]
Example 1
1.34 g (10 mmol) of copper (II) chloride (CuCl ₂ ), 1.6 g (30 mmol) of sodium methoxide, 0.178 g (1 mmol) of palladium chloride, and 20 ml of dioxane were charged into an autoclave having an inner volume of 70 ml in nitrogen, and the mixture was cooled to room temperature. Then, a synthesis gas of CO / H ₂ = 1/2 (molar ratio) was injected to 50 kg / cm ² -G, and the reaction was carried out at a reaction temperature of 120 ° C. for 3 hours. As a result of the analysis, a reaction result with a CO conversion of 96% and a methanol selectivity of 99% or more was obtained. The absorption of the pressure was completed in about 30 minutes, and the yield based on the solvent [STY (Space time yield)] was 202 g-MeOH / l / hr when the time when the pressure was reduced was regarded as the reaction time. . In this reaction, precipitation of a copper mirror due to reduction of copper (II) during the reaction was hardly observed even after the reaction was confirmed.
[0027]
Example 2
The reaction was carried out in the same manner as in Example 1 except that the charged amount of copper (II) chloride was changed to 2.01 g (15 mmol) and the charged amount of palladium chloride was changed to 0.089 g (0.5 mmol). A reaction result of 96% was obtained. The STY was 185 g-MeOH / l / hr.
[0028]
Example 3
Results of a reaction performed under the same reaction conditions as in Example 1 except that 2.1 g (30 mmol) of potassium methoxide was used instead of sodium methoxide, and the amount of palladium chloride charged was changed to 0.089 g (0.5 mmol). , A CO conversion rate of 95% was obtained. In addition, STY was 133 g-MeOH / l / hr.
[0029]
Example 4
The reaction was carried out in the same manner as in Example 1 except that 0.266 g (1 mmol) of palladium bromide was used instead of palladium chloride. As a result, a CO conversion rate of 96% was obtained. The STY was 185 g-MeOH / l / hr.
[0030]
Example 5
2.68 g (20 mmol) of copper (II) chloride (CuCl ₂ ), 1.6 g (30 mmol) of sodium methoxide, 0.119 g (0.5 mmol) of palladium sulfate dihydrate, 20 ml of triglyme, and a reaction pressure of 60 kg The reaction was carried out in the same manner as in Example 1 under the conditions of / cm ² -G and a reaction temperature of 150 ° C., and as a result, a CO conversion rate of 95% was obtained. The STY was 121 g-MeOH / l / hr.
[0031]
Example 6
The reaction was carried out in the same manner as in Example 1 except that 0.112 g (0.5 mmol) of palladium acetate was used instead of palladium chloride. As a result, a CO conversion rate of 95% was obtained. In addition, STY was 120 g-MeOH / l / hr.
[0032]
Example 7
The reaction was conducted in the same manner as in Example 1 except that 0.266 g (1 mmol) of platinum chloride was used instead of palladium chloride. As a result, a reaction result with a CO conversion of 96% was obtained. STY was 187 g-MeOH / l / hr.
[0033]
Example 8
The reaction was performed in the same manner as in Example 1 except that 3.35 g (15 mmol) of copper (II) bromide (CuBr ₂ ) was used instead of copper (II) chloride and 0.267 g (1.5 mmol) of palladium chloride was used. As a result, a reaction result with a CO conversion of 95% was obtained. STY was 172 g-MeOH / l / hr.
[0034]
Example 9
The reaction was carried out in the same manner as in Example 1 except that 1.60 g (10 mmol) of copper (II) sulfate (CuSO ₄ ) was used instead of copper (II) chloride. As a result, a CO conversion rate of 95% was obtained. Was done. The STY was 125 g-MeOH / l / hr.
[0035]
Example 10
1.60 g (10 mmol) of copper (II) sulfate (CuSO ₄ ) was used instead of copper (II) chloride, 0.355 g (1 mmol) of platinum bromide was used instead of palladium chloride, and the reaction pressure was 40 kg / cm ² −. G. The reaction was conducted in the same manner as in Example 1 under the conditions of the reaction temperature of 100 ° C., and as a result, a CO conversion rate of 95% was obtained. The STY was 95 g-MeOH / l / hr.
[0036]
Comparative Example 1
1 g (10 mmol) of cuprous chloride (CuCl), 1.6 g (30 mmol) of sodium methoxide and 20 ml of dioxane were charged into an autoclave, and 50 kg / cm of a synthesis gas of CO / H ₂ = 1/2 (molar ratio) was added at room temperature. ^The pressure was increased to ^2- G, and the reaction was carried out at a reaction temperature of 120 ° C. for 3 hours. As a result of the analysis, the CO conversion was 80%. The STY was 78 g-MeOH / l / hr. However, in this reaction, precipitation of copper mirror due to reduction of copper (I) during the reaction was confirmed after the reaction.
[0037]
Comparative Example 2
The reaction was carried out in the same manner as in Example 1 except that palladium chloride was not used, and as a result, a CO conversion rate of 94% was obtained. STY was 62 g-MeOH / l / hr.
[0038]
Comparative Example 3
The reaction was carried out in the same manner as in Example 1 except that 3.35 g (15 mmol) of copper (II) bromide (CuBr ₂ ) was used instead of copper (II) chloride, and the reaction was carried out in the same manner as in Example 1 except that palladium chloride was not used. A reaction result of 94% was obtained. STY was 60 g-MeOH / l / hr.
[0039]
【The invention's effect】
According to the present invention, in a method for producing methanol from carbon monoxide and hydrogen, by reacting a divalent copper compound and a metal alkoxide compound in the presence of a solvent with a catalyst in the presence of a platinum group metal, Methanol activity (compared as STY) was significantly superior to that of the known catalysts under the reaction conditions of not more than 50 ° C. and not more than 50 ° C., and carbon monoxide conversion of not less than 90% was obtained. As a result, it is not necessary to recirculate the unreacted synthesis gas to the reaction system.Besides, since the methanol synthesis reaction can be performed at a lower pressure than in the synthesis gas production step, there is no need to increase the pressure of the raw material synthesis gas. This is an industrially advantageous production method.

Claims (1)

In producing an oxygen-containing compound from carbon monoxide and hydrogen in the presence of a solvent, (1) a divalent copper compound, (2) palladium halide, palladium oxide, palladium cyanide, palladium acetate, palladium sulfate, palladium nitrate Using a catalyst comprising at least one platinum group metal compound selected from platinum halides, platinum oxide, platinum cyanide, platinum sulfate and platinum nitrate and (3) metal alkoxide. Method.