JPH06100479A - Simultaneous preparation of acetic acid, methyl acetate and acetic anhydride - Google Patents

Abstract

PURPOSE: To symultaneously or selectively obtain acetic acid, methyl acetate and acetic anhydryde, by carbonylating methanol in a gas phase under the specified condition to prepare acetic acid and methyl acetate and afterthat preparing acetic anhydride from the residue of methyl acetate.

CONSTITUTION: First, methanol is carbonylated in the gas phase in a carbonylation reactor, in the presence of a co-catalyst comprising a rhodium catalyst and a halide, using carbon monoxide or/and the gaseous mixture composed of carbon monoxide and hydrogen (wherein 1-50% hydrogen is mixed), in a molar ratio of the gas : methanol of (1:0.1) to (1:100), at 100-400°C under a partial pressure of carbon monoxide of from atm. pressure to 1,000 psig to obtain the objective acetic acid and methyl acetate, and after a specified amount of acetic acid and methyl acetate is recovered, the residue of methyl acetate is carbonylated with carbon monoxide or the gaseous mixture composed of carbon monoxide and hydrogen, in a GHSV(Gas Hourly Space Velocity) of 50-10,000 Hr^-1 at 100-400°C to prepare and recover the objective acetic anhydride. Further the co-catalyst is recycled to use.

COPYRIGHT: (C)1994,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simultaneous production method of acetic acid, methyl acetate and acetic anhydride or a selective production method of any one of these products.

[0002]

2. Description of the Related Art Acetic acid and acetic anhydride have been conventionally used as useful chemicals for industrial purposes. Acetic anhydride is
Up to now, it has been used as a second raw material of acetic acid, especially as a raw material for producing cellulose acetate and cellulose ester. Recently, acetic acid alkyl ester, which is a derivative of acetic acid, has been used as a solvent. In particular, lower alkyl esters of acetic acid, such as methyl acetate, ethyl acetate, etc., have a wide range of applications because they can be easily converted to ethanol by hydrogenation.

Acetic acid, although in low yields, has been produced to date by oxidation of the residues of petroleum refining processes, but it was not economical. However, as the added value of petroleum residues has increased, various improved methods of acetic acid production have recently been developed. For example, a method for producing acetic acid by carbonylation of methanol using a rhodium catalyst is promising as a new catalytic step. In particular, acetic anhydride is produced by the reaction of the ketene intermediate obtained by the thermal decomposition of acetic acid from the above catalytic reaction with acetic acid in a 1: 1 ratio, but the cost of production is high. On the other hand, an alkyl ester of acetic acid can be produced by esterifying the thus obtained acetic acid with a corresponding alcohol and then dehydrating it. However, this reaction requires a long production process and is expensive. high.

From the economical aspect, various methods for producing acetic acid have been proposed so far. For example, US Patent No.
Recently, as disclosed in 3,769,329, an industrially advantageous liquid phase method of acetic acid by carbonylation of methanol has been developed, which strongly stimulates research in this technical field. For example, Fe, N as a reaction catalyst
A method for producing acetic acid using i, Co, etc. was proposed by Reppe [Justus Liebig's Ann. Chem., 58.
2, 1 (1953)]. Although various metals have been used as catalysts since this proposal, rhodium is also considered to be industrially advantageous.

US Pat. No. 4,482,497 to Rizkalla shows that the use of nickel carbonyl compounds or nickel compounds in place of rhodium with cocatalysts in a liquid phase process for the production of acetic acid from alcohols is relatively mild. Although it is disclosed that the conditions give rise to high reactivity, this method has not yet been industrialized. Further, West German Patent No. A3335595 proposes a method for producing acetic acid from alcohol in a high yield, using a molybdenum / nickel / lithium iodide / iodide catalyst system under a CO atmosphere of 83 atm. Is.

British Patent No. 2089803 discloses a process for the production of acetic acid by the carbonylation of methanol,
Here, molybdenum and tungsten promote the effect of the nickel catalyst, and various organic or inorganic iodide compounds significantly enhance the yield of acetic acid production. However, this method does not show any industrial features in productivity.

As mentioned above, the liquid phase method for industrial production of acetic acid has various practical problems, and solves the problems, and particularly eliminates the problems caused by the inevitable apparatus corrosion in the liquid phase. Many efforts have been made to do so. Therefore, in an attempt to solve the above problems encountered in liquid phase processes, gas phase processes for acetic acid production have been suggested.

For example, Toyo Engineering Corp. European Patent No. 0069514A2 and West German Patent No. 3323654, Ind. Chem. Prod. Res. Dev., 22, 436 (1983) and
Chemistry Letters, 895 (1987) report vapor phase methods for nickel-catalyzed carbonylation of methanol, but these methods have many problems from a practical point of view. European Patent No. 0335625A2
Disclosed is a method for producing acetic acid which is carried out under the condition of using a nickel / rhodium-supported activated carbon catalyst at 188 ° C. In this method, CO / H ₂ (1: 2) gas was introduced at 9 atm and the ratio of methanol to methyl iodide was 100: 1.
9.1, and the GHSV of the gas is 1. However, the yield by this method is low at 9.7%. In particular, nickel tends to volatilize from the catalyst bed during the course of the reaction, which greatly reduces the useful life of the catalyst. It has been found that rhodium is superior to nickel in terms of reactivity and stability in the vapor phase method as well as the liquid phase method.

Hockman, US Pat. No. 3,717,570 and Schultz, US Pat. No. 3,689,533, disclose heterogeneous gas phase acetic acid production processes using rhodium catalysts. These patents teach that the conversion of methanol and the yield of acetic acid are increased by mixing the Rh catalyst with the metal composition. However, in these patents, the reaction temperature is 285 ° C. and the pressure is 200 ps.
The molar ratio of i and the reaction components introduced is CH ₃ I: CH
Under the most suitable reaction conditions with ₃ OH: CO = 1: 12.3: 26.2, the conversion of methanol, the selectivity of acetic acid and the yield of acetic acid were 78.5%, 58% and 4 respectively.
It is 5.5% or less.

JP-A-48-488051 discloses cobalt-,
A gas-phase process is disclosed in which rhodium containing nickel or iron is used as a catalyst and a small amount of aluminum, copper, titanium, mercury and / or lithium is added as a cocatalyst. Under the most preferred reaction conditions of this prior art, the yield of acetic acid is 71
%, Which means that 25 g of activated carbon was added to RhCl ₃ .4H ₂ O.
Of 0.43 g, 0.43 g of NiCl ₂ , 0.44 g of AlCl ₃ and 0.43 g of LiCl were used to prepare methanol, carbon monoxide and methyl iodide at 169 g / hr, respectively. 224g / hr and 27g / hr
And the reaction is carried out at 230 ° C. under 220 psi. The yield of this method is only 71%.

[0011] Mueller et al., US Pat. No. 4,918,218 and German Patent No. 3606169 also disclose a gas phase process using a nickel / palladium complex catalyst system and a process using a zeolite carrying a cobalt catalyst, respectively. ing. Toyo Engineering Co., Ltd. (Japanese company)
We have developed a method using a nickel-based catalyst system.
However, in terms of reactivity, conversion and selectivity, all these catalysts are not industrially practical.

Recent research has been directed to a process for the simultaneous production of acetic anhydride with reduced reactor corrosivity.

GB 1468940 discloses a liquid phase carbonylation process for the preparation of acetic anhydride from monocarboxylic acid alkyl esters and alkyl iodides under anhydrous conditions. In this method, a noble metal of Group VIII, that is, a catalyst selected from iridium, osmium, platinum, palladium, rhodium, ruthenium, and lithium,
An accelerator selected from magnesium, calcium, titanium, chromium, iron, nickel, aluminum and the like is used. However, this method has the disadvantage that the reaction components have to be stored in anhydrous state, since they have to be carried out under anhydrous conditions.

British Patent No. 1523346 describes a process for producing acetic anhydride from methyl acetate and carbon monoxide in a liquid phase reaction in the presence of a metal catalyst which may be ruthenium, rhodium, palladium, osmium, iridium or platinum. Is teaching. In this method, the starting materials are preferably used in as anhydrous a form as possible, but may contain up to 25% methanol and up to 5% water. In this case, acetic acid is produced simultaneously with acetic anhydride due to the presence of methanol and water.

Removing water from the reaction components to obtain acetic anhydride is important and has always been a serious problem. Methyl acetate is usually produced by esterification between acetic acid and methanol; esterification is accompanied by the simultaneous production of large amounts of water.

British Patent No. 2033385A2 discloses a process for producing pure methyl acetate by reacting acetic anhydride with methyl acetate containing a large amount of water. In this method, the produced methyl acetate contains a large amount of water and further reacts with acetic anhydride obtained in the carbonylation step to produce acetic acid and dehydrated methyl acetate, and finally passed through the carbonylation reactor. Later, acetic acid and acetic anhydride are produced simultaneously.

In order to effectively solve the problem of the presence of water encountered in the process of producing acetic anhydride, EP-0087870A2 describes esterification of acetic acid and methanol formed and dehydration, carbonylation of the formed product. It is proposed that the steps of compounding and product separation take place in this order. This method comprises the steps of producing a mixture of methyl acetate, methanol and water by esterification of methanol with recycled acetic acid; removing a portion of water from the esterification product; acetic acid thus produced by dehydration. Methyl and CO are reacted in the liquid phase carbonylation step to produce acetic anhydride and acetic acid at the same time, depending on the water and methanol contents of the reactant components; a low boiling point halide promoter, acetic acid and Separating high boiling fractions containing acetic anhydride and catalyst composition; collecting low boiling fractions and high boiling fractions separately and recycling the low boiling fractions to the carbonylation reactor; and separating The step of recycling the acetic acid thus obtained to the esterification reactor; The production ratio of acetic acid and acetic anhydride is determined by controlling the amount of water produced and removed in the esterification process. However, this process has many problems, and it is difficult and complicated to remove water, especially after the esterification process. For example, if the esterification is carried out using a 2: 1 ratio of methanol and acetic acid, then 57.5% by weight methyl acetate, 2% methanol.
Only 7.9% by weight and 13.6% by weight of water are produced.
The water produced must be removed by azeotropic distillation of water and methanol. In addition, a separate step of separating methanol from water is needed.

[0018]

The starting material used in the above-mentioned method for producing acetic anhydride is one of the important factors. By this method methyl acetate is used as the starting material and is produced by esterification between acetic acid and methanol. This method can simultaneously produce acetic acid and acetic anhydride in a batch system; however, ultimately, the method must include the step of carbonylation of the expensive starting material, methyl acetate.
Therefore, when the starting material, ie, methyl acetate, is directly produced, the production cost of methyl acetate and acetic anhydride can be reduced. In addition to acetic anhydride, various derivatives,
In particular, anhydrous ethanol, vinyl acetate monomers, alkyl esters, propionic acid and the like can be produced from methyl acetate.

[0019]

DISCLOSURE OF THE INVENTION In order to develop an economical production method of acetic acid, methyl acetate and acetic anhydride, the inventor of the present invention has diligently studied the above conventional method of simultaneously producing acetic acid and acetic anhydride. I've been As a result, the inventor has found that the problems associated with reactor corrosion can be solved by using a highly productive gas phase reaction catalyst system, which can reliably reduce the number of conventional multi-step processes and production costs. discovered. The present invention has been achieved based on this discovery.

It is one of the objects of the present invention to provide a method for simultaneously producing acetic acid, methyl acetate and acetic anhydride on a large scale with a small number of manufacturing steps.

The catalyst system used and the reaction conditions contained therein are controlled so that the production ratio can be arbitrarily changed,
It is another object of this invention to provide a selective process for the production of acetic acid, methyl acetate and acetic anhydride.

These and other objects of the invention include:
Carbonylating methanol with carbon monoxide, optionally with hydrogen, in the presence of a rhodium catalyst and a halide cocatalyst in a first gas phase carbonylation reactor for the gas phase carbonylation of methanol. A step of producing acetic acid and methyl acetate; a step of separating methyl acetate and cocatalyst produced from the reaction mixture and recovering acetic acid; a part of methyl acetate separated by distillation is isolated, and a remaining portion of methyl acetate and co-catalyst are separated. Introducing the catalyst with carbon monoxide into a second carbonylation reactor; in the presence of a cocatalyst, methyl acetate with carbon monoxide, optionally with hydrogen,
Carbonylation to produce acetic anhydride by; and finally, separating the cocatalyst from the acetic anhydride thus obtained, recovering the acetic anhydride and transferring the cocatalyst to the first gas phase carbonylation reactor. A step of recycling; and a method of simultaneously producing acetic acid, methyl acetate and acetic anhydride.

According to the present invention, the conditions for the first carbonylation of methanol with carbon monoxide can be easily controlled and the ratio of methyl acetate to acetic acid produced can also be easily controlled. Thus, the productivity of the desired methyl acetate can be increased in a simpler way compared to the conventional production method of methyl acetate and the conventional problems due to the inclusion of water can be easily solved. .

In order to selectively produce only acetic acid, the total amount of methyl acetate produced should be recycled to the first carbonylation reactor. In this case, the selectivity to acetic acid can be increased to 99% or higher. Further, a small amount of hydrogen can be added to carbon monoxide as a raw material gas to increase the selectivity to acetic acid.

Further, the carbonylation catalyst of the present invention comprises a rhodium catalyst and one or more transition metal, alkali metal or alkaline earth metal compounds such as CoCl ₂ , RuCl ₂ .
₃ , PdCl ₂ , PtCl ₂ , OsCl ₃ , IrCl
₃ , NiCl ₂ , MnCl ₂ , ReCl ₅ , CrCl
₃ , MoCl ₃ , WCl ₆ , VCl ₃ , NbCl ₅ , T
aCl ₅ , TiCl ₃ , ZrCl ₄ , HfCl ₄ , Li
I, NaI, KI, RbCl, BeCl ₂ , MgCl
₂ , prepared by adding CaCl ₂ , SrCl ₂ , BaCl ₂ . Because the catalyst system of the present invention retains high conversion to methyl acetate and high selectivity, the problems associated with the selectivity to methyl acetate encountered with conventional heterogeneous gas phase process catalysts are facilitated. Can be resolved. In conclusion, acetic acid and methyl acetate can be effectively co-produced with a catalyst system under suitable reaction conditions.

The present invention will be described in detail below.

The method for simultaneously producing acetic acid, methyl acetate and acetic anhydride of the present invention comprises the following 5 steps:

Step 1: Acetic acid and methyl acetate are prepared by gas phase carbonylation of methanol with carbon monoxide, optionally mixed gas with hydrogen, in the presence of a halide cocatalyst. In this step, the selectivity to acetic acid increases under harsh conditions, while the selectivity to methyl acetate increases under mild conditions. In order to selectively obtain only acetic acid, the selectivity to acetic acid is determined by using a catalyst having a high selectivity to acetic acid, for example, a rhodium / lithium catalyst system, to separate the produced methyl acetate from the reaction mixture together with methyl iodide. And then recycled to the first carbonylation reactor. In this step, the selectivity to acetic acid can be kept above 99%. It is also possible to add a small amount of hydrogen to the feed gas, ie carbon monoxide, to improve the selectivity to acetic acid;

Step 2: Acetic acid is isolated and recovered from the bottom of the reactor, low boiling fractions, ie cocatalyst and methyl acetate, are separated from the top of the same reactor;

Step 3: The expected amount of methyl acetate separated in Step 2 is distilled to isolate the final product, methyl acetate, and the remainder of the methyl acetate is co-catalyzed to obtain acetic anhydride. Is introduced into the secondary carbonylation reactor;

Step 4: In this step a second carbonylation takes place, where in the presence of a cocatalyst carbon monoxide, optionally mixed gas with hydrogen, is introduced into the second reactor in Step 3. Carbonylation of methyl acetate to produce acetic anhydride; and

Step 5: The cocatalyst is separated from the acetic anhydride produced and the cocatalyst thus separated is recycled to the first carbonyl reactor.

All steps are carried out in the gas phase, but the second carbonylation can be carried out either in the gas phase or in the liquid phase, preferably in the gas phase.

The first gas phase carbonylation of methanol is
Co-pending Korean Patent Nos. 92-11524 and 92-20188 filed on June 30, 1992 in the name of the same assignee as the patent application of the present invention in the presence of a rhodium catalyst. Under the reaction conditions described in detail in.

The catalyst of the present invention for vapor phase carbonylation of methanol is obtained by supporting a solution of a rhodium compound in water or an organic solvent on an inert carrier together with an alkali metal, alkaline earth metal or transition metal compound. 2 of the resulting mixture
It can be prepared by sintering at 00 to 500 ° C. Inert carriers include activated carbon, clay, alumina,
Silica and silica-alumina.

All rhodium compounds which are soluble in water or organic solvents and which sinter at 200 to 500 ° C. to form rhodium oxide can be preferably used. Various rhodium compounds such as RhX ₃ (X = Cl, B
r, I), RhX ₃ .3H ₂ O (X = Cl, Br,
I), Rh ₂ (CO) ₄ X ₂ (X = Cl, Br, I),
[Rh (CO) X ₄ ] Y (X = Cl, Br, I; Y = N
a, Li, K), Rh ₂ (CO) ₈ , Rh (NO ₃ )
₃ , [Rh (CO) ₂ X ₂ ] Y (X = Cl, Br, I;
Y = Li, Na, K), Rh ₂ O ₃ , [Rh (C ₂ H
₄ ) ₂ X] ₂ (X = Cl, Br, I), Rh [(C ₆ H
₅ ) ₃ P ₂ ] (CO) X (X = Cl, Br, I), Rh
_{Metal, RhX [(C 6 H 5} ) 3 P] 2 (CH 3 Y) 2
(X, Y = Cl, Br, I), Rh (SnCl ₃ )
[(C ₆ H ₅ ) P] ₃ (X = Cl, Br, I), RhX
(CO) [(C ₆ H ₅ ) ₃ Y] ₂ (X = Cl, Br,
I; Y = As, P, Sb), [R ₄ Y] [Rh (CO)
₂ X] ₂ (X = Cl, Br, I; R = C ₁ -C ₁₂ alkyl; Y = N, As, P), [R ₄ Y] ₂ [Rh (CO)
_{X 4] (X = Cl,} Br, I; R = C 1 -C 12 alkyl; Y = N, As, P ), RhX [(C 6 H 5) 3 P] 3
(X = Cl, Br, I), RhX [(C ₆ H ₅ ) ₃
P] H ₂ (X = Cl, Br, I), [(C ₆ H ₅ ) ₃
P] ₃ Rh (CO) H, Y ₄ Rh ₂ X ₂ (SnX ₃ ) ₄
(X = Cl, Br, I; Y = Li, Na, K) and the like are used. Preferably, inter alia, RhCl ₃ .3H ₂ O
Alternatively, Rh (NO ₃ ) ₃ is used.

The above rhodium compounds may be added so that they are 0.1 to 20% by weight of Rh, preferably 0.6 to 5% by weight, based on the amount of inert carrier. The transition metal compound is 1 to 1000 based on the amount of rhodium.
It may be added in mol%, preferably 30 to 300 mol%. The alkali metal or alkaline earth metal compound may be added in an amount of 1 to 1000 mol%, preferably 200 to 800 mol%, based on the amount of rhodium.

The gas phase process of the present invention for producing acetic acid, methyl acetate and acetic anhydride comprises methanol or methyl acetate using a halide as a cocatalyst in the presence of a catalyst prepared according to the present invention. Reacting with carbon monoxide.

The halide catalyst used as a cocatalyst in the present invention is CH ₃ I, CH ₃ Br, CH ₃
Cl, I ₂ , Br ₂ , Cl ₂ , HI, HBr, HCl and the like. CH ₃ I is preferably used.

In the method of the present invention, the production ratio of methyl acetate to acetic acid can be adjusted by controlling the reaction conditions for the first carbonylation. If the carbonylation is carried out under more severe reaction conditions, such as high temperature,
The acetic acid production ratio increases. However, the production ratio of methyl acetate increases under mild reaction conditions. Therefore, in the method of the present invention, the production ratio of the desired product can be easily adjusted.

On the other hand, in the usual liquid phase reaction, when hydrogen is mixed as an impurity in carbon monoxide as a raw material gas, various side reactions occur and the efficiency of the catalytic reaction system is lowered. However, in the heterogeneous gas phase catalytic reaction system of the present invention, even if hydrogen is mixed in carbon monoxide in an amount of 1 to 50%, carbon monoxide does not substantially affect the reaction system. . Rather, the presence of hydrogen significantly increases the selectivity to acetic acid. Moreover, the use of carbon monoxide containing hydrogen eliminates the need to remove hydrogen from carbon monoxide, which is advantageous from an economic perspective.

The type of product from the first carbonylation depends on the reaction conditions involved. Preferably, the product consists of about 60% methyl acetate, about 20-30% acetic acid and about 10-20% unreacted methanol. The product of the above composition can be easily obtained on the first carbonylation catalyst bed. As described below according to the examples of the invention, the product having the above composition is obtained under very mild conditions. Therefore, the space velocity of the injection flow becomes faster,
Significantly increase productivity.

The separation of the first carbonylation product can be carried out by distillation. Acetic acid is separated from the bottom of the reactor and the desired amount of methyl acetate is recovered and isolated from the middle of the reactor by distillation. The methyl acetate and cocatalyst obtained by distillation from the top of the reactor are then introduced into a second carbonylation reactor to produce acetic anhydride. At this point, the reaction is accelerated by adding water or methanol. However, excess water will increase the production rate of acetic acid, so the water content should be kept as low as possible in order to prevent the formation of acetic acid.

The second carbonylation is 100 to 70
It is carried out at a GHSV of ⁰ hr ^-1 at a temperature of 100 to 300 ° C, preferably 240 to 260 ° C. Methyl acetate and halide cocatalyst introduced into the reactor, especially CH ₃
The molar ratio with I is preferably 10: 1.

The introduction pressure of carbon monoxide involved in the second carbonylation of methyl acetate is normal pressure to 1000 psi, preferably 150 to 300 psi, more preferably 2
00 psi. The reaction mixture from the second carbonylation may be separated by distillation. The cocatalyst separated in this way is recycled to the first carbonylation reactor as described above.

[0046]

INDUSTRIAL APPLICABILITY According to the present invention, mass production of methyl acetate is possible in a single step; the problem of water removal is solved;
The product separation is very simple; only acetic acid can be selectively produced, and the production ratio of acetic acid / methyl acetate / acetic anhydride in the simultaneous production can be easily controlled; because the reaction is carried out in the gas phase , Improving the corrosion resistance of all reactors; no need to recover and recycle the used catalyst; because it is possible to mass produce methyl acetate, isolate pure methyl acetate and then ester Exchanges can be made to produce various types of acetic acid alkyl esters, and also have significant advantages such as the ability to produce ethanol by hydrogenation as described in connection with the prior art above. is there.

[0047]

The present invention will be described in more detail by the following examples. The examples are for purposes of illustration only and are not intended to limit the invention as properly described in the claims.

Example 1 Activated carbon was added to RhCl ₃ and LiI
Was immersed in a solution of RhCl ₃ and LiI so that 0.6% by weight of Rh based on the amount of activated carbon and 400 mol% of LiI based on the amount of Rh were loaded on the activated carbon. . The obtained material was sintered at 300 ° C. to prepare a catalyst. Diameter 1.27 cm (0.5 inch), length 4
A 0 cm reaction tube was charged with 5 g of catalyst. Tip of reaction tube 1
Glass fibers were packed to a height of 5 cm and a height of 15 cm at the end, respectively, and a catalyst bed was formed at a height of 10 cm between the glass fibers at the tip and the end. Then, a diameter of 0.
A 64 cm (0.25 inch) tube was inserted and equipped with a thermocouple. The outside of the reaction tube was coated with oil so that the reaction tube could be heated with a heating medium. Methanol and carbon monoxide 1:
It was introduced into the reaction tube at a molar ratio of 2.3 and reacted with each other under pressure of 200 psi at an internal temperature of 240 ° C. in the presence of 10 mol% of co-catalyst CH ₃ I based on the amount of methanol.

The conversion of methanol to different GHSV and the yields of acetic acid and methyl acetate under the above conditions are shown in Table 1.

[0050]

[Table 1]

1) GHSV = gas hourly space velocity (hr ^-1 ): This is a measure of the gas phase methanol reaction components passing through the catalyst per hour. The higher the GHSV, the shorter the contact time between the reaction components and the catalyst, and the greater the amount of reaction components processed per unit time. 2) Yield of acetic acid = (mol of acetic acid produced / mol of methanol introduced into the reactant) × 100 3) Yield of methyl acetate = [(mol of methyl acetate produced) × 2 / in the reactant Mol of methanol introduced into
× 100

Example 2 This example was carried out using the same catalyst and the same reaction conditions as in Example 1, except that the reaction temperature and pressure were changed to 233 ° C. and 150 psi, respectively. The results are shown in Table 2.

[0053]

[Table 2]

As is clear from Tables 1 and 2, the production ratio of methyl acetate to acetic acid can be easily adjusted by changing the reaction conditions even when the same catalyst is used. That is, the results of Example 2 indicate that methyl acetate is produced in large quantities under relatively mild conditions.

Example 3: In this example, activated carbon was treated with LiI.
Was carried out in the same manner as in Example 1 except that the catalyst prepared by supporting 800 mol% of the above was used. The results are shown in Table 3.

[0056]

[Table 3]

Example 4 In this example, 1.8% by weight of Rh and 400 mol% of LiI based on the amount of Rh were supported on activated carbon, and the reaction temperature and the CO partial pressure were changed, respectively. The procedure was as in Example 1, except that the temperature was changed to 270 ° C. and 150 psi. The results are shown in Table 4.

[0058]

[Table 4]

Example 5: This example shows that 0.6% by weight of Rh based on the amount of activated carbon and Na based on the amount of Rh.
The procedure of Example 1 was repeated except that a catalyst prepared by supporting 200 mol% of I on activated carbon was used, and the reaction temperature and pressure were changed to 240 ° C. and 200 psi, respectively. The results are shown in Table 5.

[0060]

[Table 5]

Example 6 This example is carried out in accordance with Example 1 except that a catalyst was used in which activated carbon was loaded with 0.6% by weight of Rh and 200 mol% of KI based on the amount of Rh. It was The results are shown in Table 6.

[0062]

[Table 6]

Example 7 This example is in accordance with Example 1 except that a catalyst was used in which 0.6% by weight of Rh and 50 mol% of MgCl ₂ based on the amount of Rh were supported on activated carbon. I did. The results are shown in Table 7.

[0064]

[Table 7]

Example 8: This example is the same as Example 1 except that the catalyst in which RhCl ₃ and IrCl ₃ were supported on activated carbon in a molar ratio of 1: 0.5 was used and the reaction temperature was changed to 255 ° C. It carried out according to it. The results are shown in Table 8.

[0066]

[Table 8]

Example 9: This example shows that 0.6% by weight of Rh and 200 mol% of PdCl ₂ based on the amount of Rh.
Was carried out on a catalyst supported on activated carbon, and the reaction temperature and CO partial pressure were changed to 255 ° C. and 150 psi, respectively.
It carried out according to Example 1. The results are shown in Table 9.

[0068]

[Table 9]

Example 10: This example is the same as Example 1 except that the catalyst in which RhCl ₃ and RuCl ₃ were supported on activated carbon in a molar ratio of 1: 0.5 was used and the reaction temperature was changed to 255 ° C. It carried out according to it. The results are shown in Table 10.

[0070]

[Table 10]

Example 11: This example is the same as Example 1 except that the catalyst in which RhCl ₃ and CoCl ₂ were supported on activated carbon in a molar ratio of 1: 0.5 was used and the reaction temperature was changed to 210 ° C. It carried out according to it. The results are shown in Table 11.

[0072]

[Table 11]

Example 12: This example is the same as Example 1 except that a catalyst in which RhCl ₃ and NiCl ₂ were supported on activated carbon in a molar ratio of 1: 0.5 was used and the reaction temperature was changed to 210 ° C. It carried out according to it. The results are shown in Table 12.

[0074]

[Table 12]

Example 13: This example was carried out using the same catalyst described in Example 1 except that a certain amount of hydrogen was mixed with the carbon monoxide feed gas.

While changing the ratio of carbon monoxide to hydrogen, the mixed gas was mixed with methanol at 14.1 kg / cm 2 (20
It was introduced into the reactor under a pressure of 0 psi). At this point, the molar ratio of methanol to carbon monoxide is 1: 1.6, 250
The GHSV of methanol was maintained at 1500 at a reaction temperature of ° C. The results are shown in Table 13.

[0077]

[Table 13]

Example 14: 0.6% by weight of Rh and Rh
RhCl ₃ .H ₂ O and LiI were loaded on activated carbon in the aqueous phase so as to contain 200 mol% of LiI based on the amount of The resulting mixture was sintered at 300 ° C. to prepare a catalyst.

Using the catalyst thus obtained, this example was carried out in accordance with Example 13 except that the GHSV of methanol was maintained at 3000. The results are shown in Table 14.

[0080]

[Table 14]

Example 15: This example shows that Rh of 0.6
Using activated carbon loaded with 200 mol% of KCl based on weight% and amount of rhodium, the GHSV of methanol was 2%.
Was maintained at 000, and the procedure of Example 13 was followed. First
The results are shown in Table 5.

[0082]

[Table 15]

Example 16: Activated carbon was loaded with RhCl ₃ .3H ₂ O and PdCl ₂ in the aqueous phase so that it contained 0.6% by weight of Rh and 50 mol% of PdCl ₂ based on the amount of rhodium. It was The mixture obtained is then added to 300
A catalyst was prepared by sintering at ° C.

Using the catalyst thus obtained, this example was carried out in accordance with Example 13 except that the GHSV of methanol was maintained at 1000. The results are shown in Table 16.

[0085]

[Table 16]

Example 17: This example uses a catalyst of activated carbon loaded with RhCl ₃ such that it contained 0.6% by weight of rhodium and 50 mol% of RuCl ₃ , and the GHSV of methanol was maintained at 2000. Other than Example 13,
Was carried out according to. The results are shown in Table 17.

[0087]

[Table 17]

Example 18: Methyl acetate and CH _{3 in} a molar ratio of 10: 1 using the same reactor and the same catalyst as in Example 1.
I was introduced into the reactor. Carbon monoxide was then introduced into the reactor and a second gas phase carbonylation was performed on the reaction mixture at 250 ° C. and 200 psi. The results are shown in Table 18.

[0089]

[Table 18]

Example 19: This example was made according to Example 18 except that the same catalyst as in Example 8 was used. The results are shown in Table 19.

[0091]

[Table 19]

Example 20: This example was performed according to Example 18 except that the same catalyst as in Example 4 was used and GHSV was maintained at 500 to change the reaction temperature. The results are shown in Table 20.

[0093]

[Table 20]

Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location C07C 53/12 9356-4H 69/14 8018-4H // C07B 61/00 300 (72) Inventor Shun Kure No. 35, 161, Uomimi-dong, Dobong-gu, Seoul, Republic of Korea Special source apartment building 2 1101 (72) Inventor, Zhu Five Hearts, No. 41, No. 7, Samguk-dong, Seongbuk-gu, Seoul, South Korea

Claims (15)

[Claims] 1. A method for simultaneously producing acetic acid, methyl acetate and acetic anhydride, comprising: (a) carbon monoxide in the presence of a rhodium catalyst and a halide cocatalyst in a first carbonylation reactor; Gas phase carbonylation of methanol with a gas mixture with hydrogen, if desired, to produce acetic acid and methyl acetate; (b) separation of product and cocatalyst from reaction mixture and recovery of acetic acid; Recovering a fixed amount of the methyl acetate obtained by distillation and introducing the separated methyl acetate together with the cocatalyst into the second carbonylation reactor; (d) in the presence of the cocatalyst, carbon monoxide Producing acetic anhydride by carbonylation of methyl acetate introduced into a second carbonylation reactor, optionally with a gas mixture with hydrogen; and (e) producing a cocatalyst from the acetic anhydride formed. Away, followed by,
Recovering acetic anhydride and recycling the cocatalyst to the first carbonylation reactor; 2. The step (a) comprises 1: 0.1 to 1: 1.
Using a molar ratio of 00 and methanol and carbon monoxide, 1
Temperature of 00 to 400 ° C and atmospheric pressure to 1000 psi
The method according to claim 1, which is carried out at a partial pressure of carbon monoxide. 3. Step (a) comprises 1: 0.5 to 1:
Using a molar ratio of methanol and carbon monoxide of 2.3,
150 ~ 300 ℃ and 150 ~ 300ps
The method of claim 1 wherein i is performed at a partial pressure of carbon monoxide. 4. The method according to claim 1, wherein step (a) is carried out under mild conditions of a temperature of 300 ° C. or less and a carbon monoxide partial pressure of 200 psi or less. 5. The step (d) comprises 50 to 10000 hr.
A process according to claim 1 carried out at a GHSV of ^-1 and a temperature of 100 to 400 ° C. 6. A process according to claim 1, wherein the carbon monoxide used in steps (a) and (d) is mixed with 1 to 50% hydrogen. 7. The rhodium compound is dissolved in water or an organic solvent such that the rhodium catalyst is 0.1 to 20% by weight of rhodium, based on the amount of inert support used.
The resulting mixture is treated with 0.1 to 1 of alkali or alkaline earth metal or transition metal based on the amount of rhodium.
A process according to claim 1 prepared by supporting on an inert carrier with 000 mol%; and then sintering the resulting mixture at 100-500 ° C. 8. The rhodium compound is RhX ₃ (X═C
l, Br, I), RhX ₃ .3H ₂ O (X = Cl, B
r, I), Rh ₂ (CO) ₄ X ₂ (X = Cl, Br,
I), [Rh (CO) X ₄ ] Y (X = Cl, Br, I;
Y = Na, Li, K), Rh ₂ (CO) ₈ , Rh (NO
₃ ) ₃ , [Rh (CO) ₂ X ₂ ] Y (X = Cl, Br,
I; Y = Li, Na, K), Rh ₂ O ₃ , [Rh (C ₂
H ₄ ) ₂ X] ₂ (X = Cl, Br, I), Rh [(C ₆
H ₅ ) ₃ P ₂ ] (CO) X (X = Cl, Br, I), R
h _{metal, RhX [(C 6 H 5} ) 3 P] 2 (CH 3 Y) 2
(X, Y = Cl, Br, I), Rh (SnCl ₃ )
[(C ₆ H ₅ ) P] ₃ (X = Cl, Br, I), RhX
(CO) [(C ₆ H ₅ ) ₃ Y] ₂ (X = Cl, Br,
I; Y = As, P, Sb), [R ₄ Y] [Rh (CO)
₂ X] ₂ (X = Cl, Br, I; R = C ₁ -C ₁₂ alkyl; Y = N, As, P), [R ₄ Y] ₂ [Rh (CO)
_{X 4] (X = Cl,} Br, I; R = C 1 -C 12 alkyl; Y = N, As, P ), RhX [(C 6 H 5) 3 P]
₃ (X = Cl, Br, I), RhX [(C ₆ H ₅ ) ₃
P] H ₂ (X = Cl, Br, I), [(C ₆ H ₅ ) ₃
P] ₃ Rh (CO) H and Y ₄ Rh ₂ X ₂ (SnX ₃ ).
The method according to claim 7, which is selected from the group consisting of ₄ (X = Cl, Br, I; Y = Li, Na, K). 9. A method according to claim 7 wherein the inert carrier is selected from the group consisting of activated carbon, clay, alumina, silica and silica-alumina. 10. A process according to claim 7, wherein the rhodium compound is used such that 0.6 to 5% by weight of rhodium is present in the first carbonylation reactor, based on the amount of inert carrier. . 11. The method according to claim 7, wherein the alkali metal or alkaline earth metal is used in an amount of 200 to 800 mol%, based on the amount of rhodium. 12. The method according to claim 7, wherein the transition metal is used in an amount of 10 to 500 mol%, based on the amount of rhodium. 13. The halide cocatalyst is CH ₃ I, CH.
₃ Br, CH ₃ Cl, I ₂ , Br ₂ , Cl ₂ , HI, H
The method of claim 1 selected from the group consisting of Br and HCl. 14. The molar ratio of CH ₃ I cocatalyst to methanol or methyl acetate introduced into each of the first and second carbonylation reactors is from 0.01: 1 to 1: 1.
14. The method according to claim 13, which is 0. 15. A catalyst for carbonylation of methanol, which is prepared by the method according to claim 7.