KR950009473B1 - Method for production of acetic acid by isomerization of methy/formate - Google Patents

Abstract

The method uses a catalyst mixture comprising nickel as main catalyst, tin compd. and metal chloride as cocatalyst, iodine compd, and organic nitrogen compd. Acetic acid is prepared by 1)contacting 0.01-10.0mol of the catalyst mixture and 1mol of methyl formate with solvent selected from carboxylic acid, carboxylic ester and its mixture; and 2)reacting with stirring in the atmosphere of 10-60 atm. carbon monoxide or mixture of CO and inert gas at 140-250deg.C.

Description

Method for preparing acetic acid using methyl formate isomerization

The present invention relates to a method for preparing acetic acid using methyl formate isomerization reaction, and more particularly, to prepare acetic acid using nickel (Ni) as a main catalyst and a tin (Sn) compound and a metal chloride as a promoter. It is about a method.

Acetic acid is one of the important basic chemical products, as well as acetic acid derivatives, for example, a basic raw material for the production of chemical products such as acetic anhydride, vinyl acetate, vinyl tetravinyl alcohol, and various uses thereof. Such acetic acid production is usually accomplished by carbonylation of methanol and reaction catalysts as described in US Pat. Nos. 3,689,533 and 3,717,670 3,887,489, South African Patent 60/2174 and French Patent 1,573,130. As the above, an expensive noble metal catalyst such as rhodium (Rh) is used.

As one of the different methods of preparing acetic acid, a method of preparing acetic acid through isomerization of methylformate has been proposed. This method can be easily prepared from low concentrations of carbon monoxide. The production of acetic acid by isomerization of the methylmethylate can be produced, and the economical method is excellent. In addition, this method is a water-free reaction, which can greatly alleviate the corrosive problem and has a great advantage in the separation of products. Examples of such patents include Japanese Patent Nos. 56-8339, 57-212135, and 59-8947, but these are also expensive palladium (Pd) (Japanese Patent No. 56-83439). , Iridium (Ir), (Japanese Patent No. 57-212135), and rhodium (Rh) (Japanese Patent No. 59-8947) are used as reaction catalysts, respectively.

A method of preparing acetic acid using a low cost catalyst instead of such a noble metal catalyst has been proposed. That is, in Japanese Patent No. 56-70340, acetic acid is manufactured using a nickel catalyst. In Japanese Patent No. 57-203028, a catalytic reaction of adding molybdenum or tungsten to a nickel catalyst is disclosed in US Patent No. 3,839,428. Catalytic reactions using cobalt as an accelerator in nickel catalysts have been proposed, but due to low reactivity problems, it is difficult to put into practical use. In addition, in US Pat. No. 2,503,513, iron, tungsten, palladium, antimony, etc., which are metals capable of producing carbonyl, are used as catalysts, but they are not practical because of their low reactivity.

In order to solve the above problems, the present inventors have proposed and proposed a method for producing acetic acid which greatly improves the reactivity by using a nickel-tin and nickel-lewis acid catalyst (Korean Patent Application No. 89-20184 and No. 91-5866)

The present invention uses an inexpensive nickel catalyst instead of an expensive noble metal catalyst in the production of acetic acid by isomerization of methyl formate, and improves the economics of the reaction. In addition to the nickel catalyst, additives such as iodine compounds and organic nitrogen compounds, tin compounds, and The purpose is to improve the yield of acetic acid by improving the reactivity by adding a promoter such as metal chloride.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.

The present invention provides a method for producing acetic acid from methyl formate, the main catalyst is nickel; A promoter consisting of a main compound and a metal chloride alone or as a mixture; And a carbon monoxide having a pressure of 10-60 atm by contacting a catalytic mixture composed of an additive consisting of an iodine compound and an organic nitrogen compound with a solvent selected from the group consisting of a carboxylic acid, a carboxyl ester and a mixture together with the reactant methylformate. The present invention relates to a method for preparing acetic acid using a methyl formate isomerization reaction produced by stirring under an atmosphere or a mixed atmosphere of a carbon monoxide and an inert gas and a reaction temperature of 140-250 ° C.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention is based on the phenomenon that the alkyl formate is carbonylated at high speed under the conditions of carbon monoxide and pressure in a catalyst reactor in which a nickel catalyst, an iodine compound, an organic nitrogen group compound, and a tin compound and a metal chloride are present. That is, the present invention is an alkyl formate (HCCOR: R is an alkyl group of up to 10 carbon atoms) containing carbon monoxide in the main nickel, an iodine compound and an organic nitrogen that is an additive, and a tin compound as a promoter And by carbonylation easily in the presence of a metal chloride, it is used to change to a carboxylic acid, which can be represented by the following formula (1).

… … … … … … … … … … … … … … … … … … (One)

Therefore, this reaction can be said to be an isomerization reaction in which the elements constituting the alkylformate change to carboxylic acid through rearrangement. In the case of the reactant alkylformate, the resulting carboxylic acid is acetic acid.

Nickel (Ni) is used as the main catalyst, and tin compounds and metal chlorides are used alone or in combination as cocatalysts. These may be any of organic and inorganic compounds.

The tin compound used as the cocatalyst is preferably selected from the group consisting of tetrabutyltin, tetramethyltin, tetraamyltin and mixtures thereof. Any metal chloride can be applied to the present invention as a metal chloride. Importantly, it must be well soluble in the solvent, so it may be iron chloride, zinc salt, zirconium chloride, antimony chloride, aluminum chloride and titanium.

The amount of the tin compound used as the cocatalyst is preferably 0.01 mole or more, more preferably 0.5-5.0 mole, with respect to 1 mole of nickel as the main catalyst, and the amount of metal chloride added is preferably with respect to 1 mole of nickel. Preferably it is 0.01 mol or more, More preferably, it is 0.5-10.0 mol.

In the present invention, a mixture of an iodine compound and an organic nitrogen group compound is used as a component that forms a ligand and serves to stabilize the product.

As the iodine compound, methyl iodine is preferable, and as the organonitride compound, an amine or a pyridine-based compound containing an alkyl group is generally used. Examples thereof include tributylamine, 2-hydroxypyridine, and a mixture thereof. Can be mentioned.

The addition amount of the iodine compound is preferably 10.0 mol or more, more preferably 100-1000 mol with respect to 1 mol of nickel as the main catalyst, and the addition amount of the organonitrogen compound is preferably 0.001 mol or more with respect to 1 mol of nickel, More preferably, it is 0.05-5.0 mol.

The catalyst-based mixture composed of the main catalyst, the cocatalyst and the additive promotes the reaction of methylformate to acetic acid. When each component described above is added below the lower limit, the reaction of methylformate to acetic acid is prevented. It hardly occurs or occurs slowly, and if it is added above the upper limit, since there is little activity increase effect, the increase rate of the addition effect decreases.

On the other hand, as a solvent for dissolving solid substances such as a catalyst, it is preferable to use carboxylic acid or carboxyl ester itself which has a high boiling point and which is not used as a reactant under reaction conditions.

The mixing ratio of the reactant methyl formate and the catalyst mixture is preferably such that the amount of the iodine compound in the catalyst mixture is 0.01-1 mol, preferably 0.1-3 mol, relative to 1 mol of methyl formate.

When the amount of the iodine compound is 0.01 mol or less, the reaction hardly occurs. When the amount of the iodine compound is 10 mol or less, the reactivity is good but the rate of increase of the reaction rate decreases. Therefore, the upper limit is preferably 10 mol in consideration of economic aspects. .

The components of the reaction mixture can be mixed in any order, and the pressure of pure carbon monoxide introduced during the stirring reaction is preferably about 10 to 60 atm, because the reaction rate is slow at less than 10 atm and at more than 60 atm. This is because tetracarbonyl is formed so that nickel is not stabilized and cannot act as a catalyst, but also requires a high pressure reactor to maintain a high pressure.

In addition, while maintaining the one-part partial pressure in the above-described pressure range to carbon monoxide, even if the remainder is replaced with an inert gas, the reactivity can be maintained high, thereby having an economic advantage.

As described above, when a part of carbon monoxide is replaced with an inert gas, it is preferable that the partial pressure of CO in the total pressure is 35% or more.

And too high pressure, that is, pure carbon monoxide pressure of more than 100 atmospheres, will result in deactivation of the catalyst.

It is preferable that the temperature is raised to a temperature range of 140-250 ° C., which is the reaction temperature at room temperature, and preferably stirred for 0.5 hour, and then reacted at low temperature for 1-4 hours to obtain a substantially substantial yield.

The reaction by the process of the invention can be separated and purified by conventional methods using a batch reactor or by continuous operation. For example, when performing a known distillation operation using a characteristic that the carboxylic acid has a higher boiling point than other possible products or reaction residues, the volatile components having a low point can be separated first, and then the remaining carboxylic acid can be recovered. have. According to the method of the present invention as described above, by using an alkyl formate having an alkyl group having 1 to 10 carbon atoms, the corresponding carboxylic acid can be variously produced according to demand.

Hereinafter, the present invention will be described in more detail with reference to Examples.

EXAMPLE

Invention Example 1

0.811 mole of methyl formate as a main reactant, 0.791 mole of acetic acid as a solvent, 0.386 mole of metal iodine as an iodine compound, 0.042 mole as tributylaman as an organic nitrogen compound, 4.26 mmole of nickel powder as a main catalyst and 5.8 mmole of tetramethyltin as a promoter. Zirconium chloride, metal chloride, 3.0mmole was added to a 300ml volume of high temperature and high pressure agitation reactor (commonly known as autoclave reactor), and purged with carbon monoxide five times. At room temperature, 20 atmospheres of carbon monoxide and 40 atmospheres of inert gas, that is, nitrogen pressure, were injected. After loading, stirring was started. Subsequently, the temperature of the reactor was increased at a rate of 6.3 ° C./mol to reach a reaction temperature of 190 ° C., and the reaction was started. After 30 minutes, 1 hour and 2 hours after the start of the reaction, the product mixture was analyzed and the conversion rates of methyl formate were 62%, 84% and 92%, respectively, and the selectivity was 92%, 89% and 92%, respectively.

Comparative Example 1

In the same manner as in Inventive Example 1, methyl iodine, tributylaman, tetramethyltin, and metal chloride were reacted for 2 hours without the addition of zirconia chloride, and the resultant compound was collected and vaccinated. The conversion rate was 16.0%, and the yield for acetic acid was 92.0%.

Comparative Example 2

In the same manner as in Inventive Example 1, but after the reaction for 2 hours without the addition of tetrabutyltin and zirconium chloride, the product mixture was collected and analyzed, the conversion rate of methyl formate was 27%, the selectivity was 87.5%.

Invention Example 2

In order to determine the initial reaction rate, the reaction mixture was reacted at 220 ° C. under the same conditions as in Inventive Example 1, and the resulting mixture was analyzed after 30 minutes, 1 hour, and 2 hours. The conversion rates were 92%, 99%, The 99,9% selectivity was 72%, 99%, 99 5%.

Invention Example 3

In order to determine the initial reaction rate for the nickel catalyst was carried out in the same manner as in Inventive Example 1, after reducing the amount of nickel powder as a catalyst from 4.26mmole to 2.13mmole and reacted at a reaction temperature of 220 ℃, 30 minutes, 1 hour, After 2 hours, the resultant mixture was collected and analyzed. The conversion rate of methyl phate was 76%, 96%, 99,8%, and the selectivity was 80%, 88% and 89%, respectively.

Invention Example 4

In order to determine the initial reaction rate for the nickel main catalyst was carried out in the same manner as in Inventive Example 1, after reducing the amount of nickel powder as a catalyst from 4.26mmole to 1.065mmole and reacted at a reaction temperature of 220 ℃, 30 minutes, 1 hour After 2 hours, the product mixtures were collected and analyzed. The conversion rates of methyl formate were 78%, 95% and 99%, respectively, and the selectivity was 55%, 76% and 83%, respectively.

Invention Example 5

In order to simulate the economic process using an inert gas was carried out in the same manner as in Inventive Example 1, after reacting the pressure of the initial pure carbon monoxide to 60 atm, the reaction mixture was collected and analyzed after 30 minutes, 1 hour, 2 hours The conversion rate of methyl formate was 56%, 78%, 98%, and the selectivity was 69%, 67% and 99%, respectively.

Invention Example 6

The reaction was carried out in the same manner as in Inventive Example 1, but the reaction was carried out by reducing the amount of methyl iodine to 0.016 mole, and the conversion ratio was 76%, 93%, and the selectivity was 52%, respectively. , 64%.

Invention Example 7

In order to examine the effect of the metal chloride was carried out in the same manner as in Inventive Example 1, but the reaction mixture was replaced by a titanium chloride of 2.74mmole used as a cocatalyst to react the reaction mixture after 30 minutes, 1 hour, 2 hours The sampling rate was 66%, 87%, 95%, and the selectivity was 96%, 92% and 99%, respectively.

Inventive Example 8

In order to observe the effect of the addition of metal chlorides, the reaction was carried out in the same manner as in Inventive Example 1, but the reaction was carried out without a metal chloride as a promoter, and the resulting mixture was analyzed after 30 minutes, 1 hour, and 2 hours. , 76%, 93%, and selectivity were 81%, 71%, 77%, respectively.

In the above examples, the conversion rate, selectivity, yield and reaction rate used are values calculated according to the following equation.

Meanwhile, in order to compare the present invention and the conventional method, Representative Examples of the Inventive Example 1 and Inventive Example 4 and the conventional method are shown in Table 1 below.

As shown in the above Examples, Inventive Example (1-8) in accordance with the present invention is superior in conversion rate and selectivity of methyl formate as compared to Comparative Example (1-2) outside the scope of the present invention, As shown in Table 1, it can be seen that the reaction rate is superior to the conventional method.

As described above, the present invention not only uses expensive noble metal catalysts, but also uses a cheap nickel-based catalyst, thereby increasing economic efficiency and significantly improving the reactivity thereof compared to the case of using a conventional nickel-based catalyst.

Claims (10)

In the method for producing acetic acid from methyl formate, Nickel which is a main catalyst; Cocatalyst consisting of a mixture or a mixture of tin compounds and metal chlorides; A mixture of iodine compounds and organonitrogen compounds is brought into contact with a catalyst mixture composed of lead additives with a reactant methylformate and a solvent selected from the group consisting of carboxylic acids, carboxyl esters and mixtures thereof, and carbon monoxide at 10-60 atmospheres. A method for producing acetic acid using a methyl formate isomerization reaction, characterized in that acetic acid is recovered by stirring and reacting in a reaction atmosphere and a reaction temperature of 140-250 ° C. The acetic acid according to claim 1, wherein the reaction atmosphere is a mixed atmosphere in which a part of the carbon monoxide is replaced with an inert gas, and the partial pressure of carbon monoxide is 35% or more of the total pressure. Manufacturing method. The method for producing acetic acid using methyl formate isomerization according to claim 1 or 2, wherein the iodine compound is methyl iodine. The process for producing acetic acid using methylformate isomerization according to claim 1 or 2, wherein the organonitrogen compound is selected from the group consisting of tributylamine, 2-hydroxypyridine and mixtures thereof. The method for preparing acetic acid using methyl formate isomerization according to claim 1 or 2, wherein the tin compound is selected from the group consisting of tetrabutyline, tetraamyltin and mixtures thereof. The method for producing acetic acid using methyl formate isomerization according to claim 1 or 2, wherein the metal chloride is selected from the group consisting of chlorides of zirconium, titanium, zinc, aluminum and mixtures thereof. The methyl formate isomerization according to claim 1 or 2, wherein the catalyst mixture is composed of at least 0.01 mol of cocatalyst, at least 10 mol of iodine compound, and at least 0.001 mol of organonitrogen group compound with respect to 1 mol of nickel as the main catalyst. Acetic acid production method using the reaction. The catalyst mixture according to claim 7, wherein the catalyst mixture is composed of 100-1000 moles of cocatalyst consisting of a mixture of 0.5-5.0 moles of tin compound and 0.5-l0.0 moles of metal chloride alone or with respect to 1 mole of nickel as the main catalyst. A method for producing acetic acid using a methyl formate isomerization reaction, characterized in that it is composed of an iodine compound and 0.05-5.0 moles of an organic nitrogen group compound. 9. The methyl according to claim 1, 2 or 8, wherein the reactant is made such that the mixing ratio of methyl formate and the catalyst mixture is 0.01-10.0 mol of the iodine mixture in the catalyst mixture with respect to 1 mol of methyl formate. Method for producing acetic acid using formate isomerization reaction. 10. The method according to claim 9, wherein the mixing ratio of the reactant methyl formate and the catalyst mixture is 0.1-3.0 mol of the iodine compound in the catalyst mixture with respect to 1 mol of methyl formate. Manufacturing method.