JP4609613B2 - Carbon monoxide production method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for decomposing methyl formate to produce high purity carbon monoxide. High purity carbon monoxide is an important substance as a main raw material of C1 chemistry or as a carbonation raw material.
[0002]
[Prior art]
As a method for decomposing methyl formate to obtain carbon monoxide, U.S. Pat. No. 3,812,210 describes a method in which gas phase pyrolysis is performed at 200 to 500 ° C. using a solid catalyst made of an alkaline earth metal oxide. . Japanese Patent Application Laid-Open No. 52-36609 describes a method for thermal decomposition at 200 to 550 ° C. using activated carbon as a catalyst. However, these methods are disadvantageous in terms of thermal energy because they require a temperature of 200 ° C. or higher, and impurity generation during the decomposition of methyl formate is inevitable, and is not suitable for obtaining high-purity carbon monoxide. Meanwhile, US Pat. No. 3,716,619 describes a method in which methyl formate coexisting with methanol is pyrolyzed at a temperature of 35 to 200 ° C. at a pressure of 2500 psig (17.3 MPa) or less using sodium methoxide as a catalyst. Has been. However, since this method also uses sodium methoxide as a homogeneous catalyst, separation and recovery steps from the product are necessary, and the process becomes complicated. Furthermore, JP-A-9-40413 describes a method for obtaining carbon monoxide under mild conditions of 20 to 100 ° C. using a strongly basic anion exchange resin. However, in this case as well, the trace amount of water contained in the raw material reacts with methyl formate, and the strong basic anion exchange resin is easily poisoned and deactivated by the generated formic acid. Difficult to manufacture.
[0003]
[Problems to be solved by the invention]
Various methods are known for the production of carbon monoxide, but as described above, impurities are easily generated in the decomposition reaction of methyl formate at a high temperature, and in the case of obtaining high purity carbon monoxide, after the decomposition reaction, It is common to provide a purification process such as gas purification, eg adsorption or absorption separation. In addition, when a strongly basic ion exchange resin is used, methyl formate can be decomposed under mild conditions to obtain carbon monoxide, but poisoning of acidic substances is inevitable, and regeneration with an aqueous alkali hydroxide solution is inevitable. A process is required, which leads to time loss and increases the raw material cost of the alkali hydroxide.
The object of the present invention is to eliminate the purification process of the obtained carbon monoxide gas and the regeneration process of the ion exchange resin when producing carbon monoxide by decomposing methyl formate in the presence of the ion exchange resin. To provide a method for producing high-purity carbon monoxide which is superior in terms of process and thermal energy and stably over a long period of time.
[0004]
[Means for Solving the Problems]
As a result of intensive studies to solve the above-described problems, the present inventors coexisted a strongly basic anion exchange resin and 1.0 to 10.0 times moles of metal alcoholate with respect to the water in methyl formate. As a result, the decomposition reaction proceeds under mild conditions that are superior in terms of thermal energy, and high-purity carbon monoxide as a target product can be stably obtained over a long period of time with high selectivity. In addition, the present inventors have found that a carbon monoxide gas purification process and an ion exchange resin regeneration process are unnecessary and are extremely advantageous from an economical viewpoint, and the present invention has been completed.
That is, the present invention is a carbon monoxide characterized by decomposing methyl formate in the presence of a strongly basic anion exchange resin and 1.0 to 10.0 moles of metal alcoholate with respect to the water in methyl formate. It is a manufacturing method.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
In the following, the raw material methyl formate used in the present invention specifically explaining the present invention may be an industrial grade, and the water content is usually 50 to 200 ppm.
[0006]
The strongly basic anion exchange resin used in the present invention is obtained by introducing a resin having a crosslinked structure as a base material and introducing an anion exchange group thereto. As the matrix of the resin, styrene-divinylbenzene-based crosslinked polystyrene, acrylic acid-based polyacrylate, or a heat-resistant aromatic polymer into which an ether group or a carbonyl group is introduced is used. Generally, an anion exchange group in an ion exchange resin is known as an amino group, a substituted amino group or a quaternary ammonium group. In the case of a strongly basic anion exchange resin used in the present invention, an anion is used. Among the quaternary ammonium groups as an exchange group, a trialkyl-substituted nitrogen atom (—N ⁺ R ₃ ) is introduced, or a dialkylethanolamine cation such as —N ⁺ (CH ₃ ) _2. (C ₂ H ₄ OH ). Examples of the strong base anion exchange resin used in the present invention include Amberlyst A-26, Dowex TG-550A, Levacit M504, Diaion PA306 and the like.
[0007]
Examples of the metal alcoholate used in the present invention include alkali metal alcoholates and alkaline earth metal alcoholates such as lithium methoxide, sodium methoxide, potassium methoxide, cesium methoxide, calcium dimethoxide and barium dimethoxide, Used by dissolving in a solvent.
The amount of metal alcoholate used is in the range of 1.0 to 10.0 times mol, preferably 2.0 to 7.0 times mol, of the water in the raw material methyl formate. If the amount used is less than this, the strongly basic anion exchange resin is poisoned due to the influence of water in methyl formate and deactivated. On the other hand, if the amount used is larger than this, the cost of the metal alcoholate increases, which is economically disadvantageous.
[0008]
As the metal alcoholate solvent, alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and 1-pentanol can be used. The concentration of metal alcoholate in the solvent is usually 2.0 to 28.0% by weight, preferably 5.0 to 15.0% by weight. However, by considering the reaction conditions and the like, the selection is not limited to the above range and can be selected as appropriate.
[0009]
In the method of the present invention, the reaction temperature and reaction pressure can be widely selected depending on the amount of methyl formate supplied, the amount of strongly basic anion exchange resin used, and the target reaction rate.
In general, the reaction temperature is preferably in the range of 0 to 150 ° C, particularly 20 to 100 ° C. When the reaction temperature is too low, a practical reaction rate cannot be obtained, and when the reaction temperature is too high, side reactions and deactivation of the ion exchange resin are liable to be disadvantageous.
The supply amount of methyl formate is in the range of 0.1 to 3.0 (mL / resin mL · hr) per unit time and the capacity of the ion exchange resin, and 0.2 to 1.5 is particularly common.
[0010]
Although the reaction pressure in the method of the present invention can be decomposed under the vapor pressure indicated by the decomposition temperature, a lower pressure is advantageous in equilibrium. In general, the reaction pressure is preferably from normal pressure to 3.0 MPa, and practically from normal pressure to 2.0 MPa.
[0011]
The reaction system in this reaction is not particularly limited as long as it is a system in which the raw material and metal alcoholate are in contact with a strong basic anion exchange resin as a catalyst. As a general reaction system, a fluidized bed, a fixed bed or the like can be mentioned, and either a batch system or a continuous system can be used.
[0012]
The carbon monoxide obtained by the present invention has a very high purity and does not require any further purification operation. In addition, since the performance of the ion exchange resin can be maintained by the coexistence of the metal alcoholate, it is not necessary to provide a separate regeneration process for the ion exchange resin.
[0013]
【Example】
Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.
[0014]
Example 1
A double-pipe stainless steel reaction tube with a pressure regulator (inner diameter: 10 mm, length: 300 mm) is filled with 15 ml of OH type strongly basic anion exchange resin (Lebatit M504, manufactured by Bayer). Then, the solution was fed at 40 ° C., and a methanol solution of methyl formate 3 ml / hr and sodium methoxide 10 wt% was supplied at 0.17 g / hr from the bottom of the reactor. At a reaction pressure of 0.5 MPa, the reaction liquid and product gas extracted from the pressure regulator at the top of the reactor were analyzed by gas chromatography. As a result, the product gas 10 hours after the start of the reaction was 100% carbon monoxide. Yes, the decomposition rate of methyl formate was 18.9%. Furthermore, the product gas 350 hours after the start of the reaction was 100% carbon monoxide and the decomposition rate of methyl formate was 18.2%, and high-purity carbon monoxide was obtained stably over a long period of time.
[0015]
Example 2
The OH-type strongly basic anion exchange resin of Example 1 was replaced with Diaion PA306 manufactured by Mitsubishi Chemical, and the same method as in Example 1 was performed. At a reaction pressure of 0.5 MPa, the reaction liquid and product gas extracted from the pressure regulator at the top of the reactor were analyzed by gas chromatography. As a result, the product gas 10 hours after the start of the reaction was 100% carbon monoxide. Yes, the decomposition rate of methyl formate was 20.2%. Furthermore, the product gas 350 hours after the start of the reaction was 100% carbon monoxide and the decomposition rate of methyl formate was 20.1%, and high-purity carbon monoxide was obtained stably over a long period of time.
[0016]
Example 3
The same procedure as in Example 1 was performed, except that sodium methoxide in Example 1 was replaced with potassium methoxide and supplied at 0.29 g / hr. At a reaction pressure of 0.5 MPa, the reaction liquid and product gas extracted from the pressure regulator at the top of the reactor were analyzed by gas chromatography. As a result, the product gas 10 hours after the start of the reaction was 100% carbon monoxide. Yes, the decomposition rate of methyl formate was 19.0%. Furthermore, the product gas 350 hours after the start of the reaction was 100% carbon monoxide and the decomposition rate of methyl formate was 19.0%, and high-purity carbon monoxide was obtained stably over a long period of time.
[0017]
Comparative Example 1
A double-pipe stainless steel reaction tube with a pressure regulator (inner diameter: 10 mm, length: 300 mm) is filled with 15 ml of OH type strongly basic anion exchange resin (Lebatit M504, manufactured by Bayer). The solution was allowed to pass through to 40 ° C., and then 3 ml / hr of methyl formate was supplied from the bottom of the reactor. At a reaction pressure of 0.5 MPa, the reaction liquid and product gas extracted from the pressure regulator at the top of the reactor were analyzed by gas chromatography. As a result, the product gas 10 hours after the start of the reaction was 100% carbon monoxide. Yes, the decomposition rate of methyl formate was 17.2%. Further, after 350 hours from the start of the reaction, the product gas is 100% carbon monoxide, the decomposition rate of methyl formate is 0.9%, the degradation rate of methyl formate over time occurs, and the carbon monoxide is stable. It was not obtained.
[0018]
Comparative Example 2
The OH-type strongly basic anion exchange resin of Comparative Example 1 was replaced with Diaion PA306 manufactured by Mitsubishi Chemical, and the same method as Comparative Example 1 was performed. At a reaction pressure of 0.5 MPa, the reaction liquid and product gas extracted from the pressure regulator at the top of the reactor were analyzed by gas chromatography. As a result, the product gas 10 hours after the start of the reaction was 100% carbon monoxide. Yes, the decomposition rate of methyl formate was 18.3%. Further, after 340 hours from the start of the reaction, the product gas is 100% carbon monoxide, the decomposition rate of methyl formate is 0.1%, the degradation rate of methyl formate over time occurs, and the carbon monoxide is stable. It was not obtained.
[0019]
【The invention's effect】
According to the method of the present invention, by performing the decomposition of methyl formate in the presence of a strongly basic anion exchange resin and a metal alcoholate, the decomposition reaction proceeds under mild conditions superior in terms of thermal energy, and high selectivity is achieved. The high purity carbon monoxide of the target product can be obtained stably over a long period of time, and it is economically unnecessary to provide a purification process for the obtained carbon monoxide gas and a regeneration process for the ion exchange resin. Therefore, the industrial significance of the present invention is extremely large.

Claims (3)

A method for producing carbon monoxide, comprising decomposing methyl formate in the presence of a strongly basic anion exchange resin and 1.0 to 10.0-fold moles of metal alcoholate relative to the water in methyl formate. The method for producing carbon monoxide according to claim 1, wherein the metal alcoholate is an alkali metal and / or alkaline earth metal alcoholate. The method for producing carbon monoxide according to claim 1 or 2, wherein an alcohol is used as a solvent for the metal alcoholate.