JP2002173310A - Method of manufacturing carbon monoxide by liquid phase catalytic decomposition of methyl formate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for advantageously accelerating a reaction by a circulation system in a method of manufacturing carbon monoxide by the liquid phase catalytic decomposition of methyl formate. SOLUTION: Methyl formate is supplied from the lower part of a reactor, in which a solid catalyst is filled, and decomposed by the reaction in the liquid state under the temperature and pressure of a catalytic bed, at which methyl formate keeps liquid phase, and the reaction pressure is controlled by continuously taking out a gas-liquid mixed phase flow of the produced carbon monoxide, unreacted methyl formate and produced methanol from the outlet of the catalytic bed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing high-purity carbon monoxide by decomposing methyl formate. High-purity carbon monoxide is an important substance as a main raw material for C1 chemistry or as a raw material for the carbonylation reaction.

[0002]

2. Description of the Related Art The decomposition reaction of methyl formate is represented by the following formula. HCOOCH ₃ → CO + CH ₃ OH As a method of decomposing methyl formate to obtain carbon monoxide,
(A) A method of performing a gas phase pyrolysis at 200 to 500 ° C. using a solid catalyst composed of an alkaline earth metal oxide (U.S. Pat. No. 3,812,210);
A method in which methyl formate is thermally decomposed in the gas phase at a temperature of from 550 ° C. to 550 ° C. (JP-A-52-36609), and (C) methyl formate coexisting with methanol at 2,500 psi (17. A method of pyrolyzing at a pressure of 57 MPa) or less and a temperature of 35 to 200 ° C. (US Pat. No. 3,716,619) is known.

However, of the above three methods,
The methods (A) and (B) are disadvantageous in terms of thermal energy because they require a temperature of 200 ° C. or more in the gas phase, and unavoidable generation of impurities at the time of decomposition of methyl formate. Not suitable for obtaining carbon. On the other hand, the method (C) is mild in terms of conditions, but requires a system for separating and recovering the product since a homogeneous catalyst is used, which complicates the process.

[0004]

As a method for compensating for these disadvantages of the prior art, Japanese Patent Application Laid-Open No. 9-40413 discloses a method for producing high-purity carbon monoxide using a strongly basic anion exchange resin as a catalyst. Has been described. This method is characterized in that the decomposition reaction proceeds under mild conditions, high-purity carbon monoxide can be obtained with high selectivity, and the separation, recovery and reuse of the catalyst are extremely easy.

[0005] The reaction system of the above method using an ion exchange resin as a catalyst is described as follows. That is,
Any method can be adopted as long as the raw material and the strong basic anion exchange resin as a catalyst are in contact with each other. Examples of a general reaction method include a fluidized bed and a fixed bed, and the reaction can be carried out in any of a batch system and a continuous system.

For the decomposition reaction of methyl formate, various reaction systems can be employed. In the batch method, a catalyst and methyl formate are charged into a reactor and reacted at a predetermined temperature. As the reaction time elapses, the decomposition reaction proceeds, and the reaction pressure increases. However, when the reaction becomes near equilibrium, the reaction rate slows down and the reaction almost stops. Thereafter, the reactor temperature is lowered, and the carbon monoxide produced in the gas phase is extracted. In the semi-batch system, a catalyst and methyl formate are charged into a reactor and reacted at a predetermined temperature. Since the decomposition reaction proceeds with the elapse of the reaction time and the reaction pressure increases, the generated carbon monoxide can be continuously extracted at a predetermined pressure capable of maintaining the liquid phase. The liquid composition in the reactor is rich in methyl formate at the start of the reaction, but the methanol concentration increases as the reaction proceeds. As a result, the reaction rate decreases, and the amount of carbon monoxide produced decreases. Both of these two methods have the following disadvantages. Since the batch method does not extract generated carbon monoxide, the reaction rate is slow due to the influence of the equilibrium of temperature and pressure conditions, and carbon monoxide cannot be obtained continuously. In the semi-batch method, generated carbon monoxide is continuously extracted, but the reaction rate is slowed down because the proportion of methanol increases as the reaction proceeds and the liquid phase composition changes.

On the other hand, there is a distribution system as another reaction system. In this method, the raw material is continuously supplied to a reactor filled or fixed with a catalyst, carbon monoxide is continuously extracted, and a part of the liquid phase in the reactor is continuously extracted. According to this method, the liquid composition in the reactor becomes constant, and the generated carbon monoxide can be obtained constantly. In the flow system, a tank reactor can be used. In this method, a catalyst is charged into a tank reactor, and raw materials are continuously supplied to cause a reaction.
In a tank-type reactor, the inside of the reactor is often stirred for the purpose of increasing the chance of contact between the catalyst and the raw material and efficiently promoting the reaction. However, in this method, the stirring blade or the like physically destroys and damages the catalyst due to mechanical stirring operation.
In addition, when the liquid in the reactor is continuously extracted, there is a disadvantage that a filter for separating from the catalyst is easily clogged. An object of the present invention is to propose a method for making the reaction proceed more advantageously in a flow system in a method for producing carbon monoxide by liquid phase catalytic decomposition of methyl formate.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies on a method of producing a carbon monoxide by the liquid phase catalytic cracking of methyl formate in which the reaction proceeds more advantageously in a flow-through manner. The present inventors have found that a flow system in which methyl formate is supplied from the lower part of the vessel and reacted in a liquid phase gives a high single flow performance, and the present invention has been completed. That is, according to the present invention, methyl formate is supplied from the lower part of a reactor filled with a solid catalyst under the conditions of temperature and pressure of a catalyst layer capable of maintaining a liquid phase, to cause a decomposition reaction in a liquid phase, and to produce a generated monoxide. A method for producing high-purity carbon monoxide by liquid-phase catalytic decomposition of methyl formate, comprising continuously extracting a gas-liquid mixed phase flow of carbon and unreacted methyl formate and produced methanol from an outlet of a catalyst layer and adjusting a reaction pressure. .

[0009]

DETAILED DESCRIPTION OF THE INVENTION The standard boiling point of methyl formate is 31.5.
Due to the low temperature of ℃, it is necessary to pressurize the inside of the reaction system in order to carry out the reaction in the liquid phase. The use temperature of the ion exchange resin as the methyl formate decomposition catalyst is limited, and practically around 100 ° C. The vapor pressure of methyl formate at 100 ° C is 0.78MP
Since it is a, a reaction pressure higher than this is employed to keep methyl formate in the liquid phase. Therefore, the pressure employed for the methyl formate decomposition reaction in the liquid phase is determined by the type of catalyst and the reaction temperature. As a general reaction condition, the temperature is 0.
The range is preferably from 150 to 150C, particularly preferably from 20 to 100C. If the reaction temperature is too low, a practical reaction rate cannot be obtained, and if the reaction temperature is too high, concurrent side reactions and deactivation of the catalyst are likely to occur.

The advantages of the method of the present invention are as follows: (1) the use of a tubular reactor becomes possible, so that the installation area of the reactor is small; (2) a stirrer and a stirring power are not required; (4) no need to separate the catalyst, (5) stable production of carbon monoxide, (6) stable operation is possible, and the like.

The method according to the invention further has the following characteristics. That is, according to the method of the present invention, a high single-stream result is obtained. The equilibrium of the liquid phase methyl formate decomposition reaction is the equilibrium of the gas-liquid mixed phase system, but the equilibrium reaction rate is the parallel reaction rate of the gas-liquid mixed phase (OATagaev, YAPazderskii, IMGutor and IIMo
gaseous phase equilibrium reaction rate (alG is DRStull, EFWwstru) than iseev, Kint. I Katal., 27, 1122 (1986)
m, JR and GCSinke., The Chemical Thermodynamics o
f Organic Compounds, using the value of WILEY).
Naturally, a high performance was obtained when the feed rate was relatively low, but surprisingly, the methyl formate conversion at a low feed rate was close to the equilibrium conversion in the gas phase.

The reason is considered as follows. The ion exchange resin as a catalyst was charged into the reactor, and the outside of the reactor was heated so that the temperature of the catalyst layer became a predetermined temperature. The raw material methyl formate was supplied upward from the lower part of the reactor. The decomposition reaction of methyl formate occurs in the catalyst layer, but the volume of generated carbon monoxide is much larger than the volume of liquid compared to the volume of liquid. For example, if one mole of liquid methyl formate reacts at normal pressure, the generated carbon monoxide and the same mole of methanol are generated at the same time, but if the methanol is liquid, the respective volumes are different. Before the reaction; Raw material methyl formate (liquid) 1 mol 60 ml After the reaction; Carbon monoxide (gaseous) 1 mol 22,400 ml Methanol (liquid) 1 mol 40 ml Actually, liquid methyl formate forms the catalyst layer from the bottom to the top. Since the reaction proceeds sequentially during the passage, this trial calculation example is assumed to correspond to the outlet of the catalyst layer. Even if the temperature and pressure of the catalyst layer are taken into consideration, the volume ratio of the generated carbon monoxide / liquid is considerably large, and is about several tens to 100. In other words, considering the volume ratio of generated carbon monoxide / liquid under the reaction conditions, only a few% of the liquid is present in the carbon monoxide gas, and the liquid is in a state close to a mist or mist. It is easily imagined that it exists. Although the system is a gas-liquid mixed phase, it is interpreted as if it approaches a gas phase, and as a result, a reaction rate close to the equilibrium reaction rate of the gas phase is obtained. Another reason is to continuously extract the gas-liquid mixed phase flow of generated carbon monoxide and unreacted methyl formate and generated methanol from the catalyst layer and adjust the reactor pressure to maintain a steady state in the reactor. What you can do is listed.

In the present invention, an ion exchange resin is suitably used as a solid catalyst used for decomposing methyl formate. More preferred are strongly basic anion exchange resins. This strong basic anion exchange resin is obtained by introducing a resin having a crosslinked structure as a base and introducing an anion exchange group into the resin.
As the resin base, styrene-divinylbenzene-based cross-linked polystyrene or acrylic acid-based polyacrylate, or a heat-resistant aromatic polymer into which an ether group or a carbonyl group is introduced is used. In general, amino groups, substituted amino groups, quaternary ammonium groups, and the like are known as anion exchange groups in ion exchange resins. However, in strongly basic anion exchange resins used in the present invention, ion exchange groups have A quaternary ammonium group having an alkyl-substituted nitrogen atom or a quaternary ammonium group having a dialkylethanolamine cation, for example, -N + (CH ₂ ) _2. (C ₂ H ₄ O
Those having an anion exchange group which is H) are preferred.
As for the strongly basic anion exchange resin used in the present invention, a commercially available product is exemplified as Amberlyst A-2.
6 (manufactured by Organo), Dowex TG-550A (manufactured by Dow Chemical), Levatit M504 (manufactured by Bayer), and Diaion PA306 (manufactured by Mitsubishi Chemical).

The raw material methyl formate according to the present invention is used alone or in the presence of a solvent. As the solvent, alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol and 1-pentanol are used. The use ratio of alcohols is 10 times by weight or less, and preferably 3 times by weight or less, based on methyl formate. In the method of the present invention,
The range of this usage ratio is not particularly limited,
It is appropriately selected in consideration of the amount of the catalyst used, the reaction conditions, and the like.

[0015]

Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

Examples 1 to 4 A stainless steel reaction tube having an inner diameter of 10 mm and a length of 300 mm was filled with 15 ml of an ion exchange resin (Levatit M504).
The temperature of the catalyst layer was adjusted by passing a heat medium adjusted to a predetermined temperature through the jacket of the reaction tube. The methyl formate raw material was supplied to the lower part of the reaction tube by a quantitative pump. The supply amount was determined from the weighed value on which the methyl formate tank was loaded, and arranged by the liquid hourly space velocity (LHSV), which is the supply liquid methyl formate volume relative to the packed catalyst volume. A gas-liquid mixed phase flow of carbon monoxide and unreacted methyl formate and methanol produced at the outlet of the catalyst layer was continuously withdrawn through a pressure regulator set at a predetermined pressure to adjust the reaction pressure. The mixed gas of carbon monoxide gas, unreacted methyl formate and the produced methanol which came out of the pressure regulator was separated into carbon monoxide and the mixed solution by a gas-liquid separator cooled to minus 70 ° C. Carbon monoxide was weighed with a gas flow meter and analyzed with a gas chromatograph.
The mixed solution was withdrawn so that the liquid level of the separator became constant, and analyzed by gas chromatography. Table 1 shows the experimental results. Table 1 also shows the gas-liquid mixed-phase equilibrium reaction rate and the gas-phase equilibrium reaction rate. It can be seen that the results of Examples 1 to 3 are higher than the gas-liquid mixed-phase equilibrium reaction rate and close to the gas-phase equilibrium reaction rate.

[0017]

[Table 1]

From these experimental results, the volume ratio between carbon monoxide and the mixture at the outlet of the catalyst layer under the reaction conditions was calculated, and the results are shown in Table 2.

[0019]

[Table 2]

As a result, the ratio of the carbon monoxide gas phase at the outlet of the catalyst layer under the reaction conditions is about 99% in each of the examples, and the volume of the mixed solution is 1% or less, and the mixture is in a state close to mist or mist. It is presumed to exist. Therefore, it is considered that a gas-phase reaction had occurred, and as a result, a reaction rate close to the equilibrium reaction rate of the gas phase was obtained.

Comparative Example 1 A methyl formate decomposition experiment was performed in a batch mode. Internal volume 10
Methyl formate in a 0 ml stainless steel autoclave
0 g, and then treated with a 1N aqueous solution of NaOH to form an OH-type strongly basic anion exchange resin (Levatit M).
504) was added and reacted at 60 ° C. for 1 hour. After cooling the autoclave to room temperature, the produced gas was extracted and analyzed by gas chromatography. The liquid was taken out of the autoclave and analyzed by gas chromatography. As a result, 100% of the resulting product gas is carbon monoxide,
The conversion of methyl formate was 29.1%.

Comparative Example 2 A methyl formate decomposition experiment was performed in a semi-batch mode. Internal volume 1
60.4 g of methyl formate was charged into a 00 ml tank-type stainless steel autoclave with a stirrer, and 10.3 ml of a strong basic anion exchange resin (LEVATIT M504) treated with an aqueous 1N-NaOH solution to form an OH type was added and reacted at 60 ° C. . The reaction pressure was set to 1.1 MPa, and the produced gas was withdrawn for 6.2 hours and analyzed by gas chromatography. The resulting product gas was 100% carbon monoxide, and the reaction rate of methyl formate was 52.4%.

[0023]

EFFECTS OF THE INVENTION In a method for producing carbon monoxide by the liquid phase catalytic decomposition of methyl formate, as a result of intensive research on a method of making the reaction proceed more advantageously in a flow system, methyl formate was supplied from the lower part of the reactor filled with the catalyst. It was found that the flow system in which the reaction was conducted under the liquid phase gave a high single flow performance. That is, according to the present invention, high-purity carbon monoxide can be produced with high single-flow performance by decomposing methyl formate in a liquid phase under mild reaction conditions using a simple apparatus. Further, the advantages of the present invention are as follows: (1) the use of a tubular reactor becomes possible, so that the reactor installation area is small; (2) a stirrer and a stirring power are not required; (3) destruction of a catalyst by a stirring operation; No damage, (4) no need for catalyst separation, (5) steady production of carbon monoxide, (6) stable operation. Therefore, the industrial significance of the present invention is extremely large.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Yasuyuki Matsumura 9-2 Kizugawadai, Kizu-cho, Kizu-cho, Soraku-gun, Kyoto Prefecture Within the Research Institute for Global Environmental Technology (72) Inventor Mikio Yoneoka Taishihama, Niigata City, Niigata Prefecture 182% F-term in Niigata Research Laboratory, Mitsubishi Gas Chemical Company 4G046 JA01 JB02 JB11 4H006 AA02 AC41 BA72 BC11 BC14 FE11

Claims (5)

[Claims] 1. A method for supplying methyl formate from a lower part of a reactor filled with a solid catalyst under a temperature and pressure condition of a catalyst layer capable of maintaining a liquid phase in which methyl formate holds a liquid phase, to cause a decomposition reaction in a liquid phase, and to produce a produced monoxide. A method for producing high-purity carbon monoxide by liquid phase catalytic decomposition of methyl formate, comprising continuously extracting a gas-liquid mixed phase flow of carbon and unreacted methyl formate and produced methanol from an outlet of a catalyst layer and adjusting a reaction pressure. 2. The solid catalyst is an ion exchange resin.
A process for producing carbon monoxide by liquid phase catalytic decomposition of methyl formate according to the above. 3. The method for producing carbon monoxide by liquid phase catalytic decomposition of methyl formate according to claim 2, wherein the ion exchange resin is a strongly basic anion exchange resin. 4. The liquid phase catalytic decomposition of methyl formate according to claim 3, wherein the strongly basic anion exchange resin has a quaternary ammonium group having a trialkyl-substituted nitrogen atom or a quaternary ammonium group having a dialkylethanolamine cation. For producing carbon monoxide. 5. The method for producing carbon monoxide according to claim 1, wherein methyl formate is decomposed in the presence of an alcohol.