Method for producing vinyl acetate

Abstract

Provided is a method for producing vinyl acetate includes at least: a step (1) for reacting ethylene, acetic acid and oxygen with one another to obtain a crude product containing vinyl acetate; a step (2) for separating a gaseous composition containing ethylene and vinyl acetate from the crude product; and a step (3) for introducing at least a portion of the gaseous composition into a gas cleaning column and removing vinyl acetate from the gaseous composition. The gas cleaning column has at least an outlet (A) and an outlet (B). The total content of acetic acid and water is 70 mass% or more in a liquid composition (α) taken out through the outlet (A). The total content of vinyl acetate and acetic acid is 90 mass% or more and the content of water is 10 mass% or less in a liquid composition (β) taken out through the outlet (B). As a result, in the method for producing vinyl acetate, the energy required for separating vinyl acetate, water, and acetic acid by distillation is reduced.

Description

Vinyl acetate manufacturing method

[0001] The present invention relates to a method for producing vinyl acetate, particularly comprising at least a step (1) of reacting ethylene, acetic acid, and oxygen to obtain a crude product containing vinyl acetate, a step (2) of separating the crude product into a liquid composition containing vinyl acetate, acetic acid, and water and a gaseous composition containing ethylene and vinyl acetate, and a step (3) of introducing at least a portion of the gaseous composition into a gas washing column and washing the gaseous composition with acetic acid and water to remove vinyl acetate from the gaseous composition.

[0002] Vinyl acetate is a useful compound used as a raw material for polyvinyl acetate. The Wacker process is widely used for its industrial production, in which vinyl acetate is produced from ethylene, acetic acid, and oxygen.

[0003] Patent Document 1 shows an example of a specific production method by the Wacker process, which comprises reacting ethylene with acetic acid and oxygen in one reactor, and a) separating a product gas stream containing mainly ethylene, vinyl acetate, acetic acid, water, carbon dioxide and other inert gases, and b) separating ethylene and CO ２ and returning a recycle gas stream containing CO to the reactor, wherein: c) the recycle gas stream is compressed in a recycle gas compressor before being returned to the reactor; and d) a partial stream of the recycle gas is branched off to the suction side or to the compression side of the recycle gas compressor, ２ and e) feeding the CO ２ 1. The method for producing vinyl acetate in a continuous gas-phase process using a heterogeneous catalyst, by washing in a water scrubber before scrubbing, comprising: f) removing the partial stream from the CO ２ After scrubbing, an injection compressor is used to pump ethylene into the compression side of the circulation gas compressor and CO ２ and / or g) feeding the bottom product directly from the water scrubber to a pre-dehydration column.

[0004] a partial stream of the recycle gas containing CO ２ By scrubbing, CO generated as a by-product in the vinyl acetate synthesis reaction can be removed. ２ This prevents the accumulation of CO in the circulating gas. ２ Before being subjected to scrubbing, the gas is passed through a water scrubber to wash it with water and acetic acid, thereby removing vinyl acetate from the gas. When the gas is washed in this manner, a bottom product containing water, acetic acid, and vinyl acetate is produced at the bottom of the water scrubber. This bottom product is distilled together with a crude reaction product containing vinyl acetate, thereby obtaining vinyl acetate from which water and acetic acid have been separated.

[0005] Special Publication No. 2012-524757

[0006] When vinyl acetate is produced by the method described in Patent Document 1, thermal energy such as steam is required to separate acetic acid, water, and vinyl acetate by distillation. In particular, a large amount of energy is required to evaporate a large amount of water, and therefore, a method for reducing this energy has been desired.

[0007] The present invention has been made to solve this problem, and an object of the present invention is to reduce the energy required to separate vinyl acetate, water, and acetic acid by distillation in a method for producing vinyl acetate.

[0008] The above-mentioned problems are solved by the following invention: [1] A method for producing vinyl acetate, comprising at least the steps of: (1) reacting ethylene, acetic acid, and oxygen to obtain a crude product containing vinyl acetate; (2) separating the crude product into a liquid composition containing vinyl acetate, acetic acid, and water, and a gaseous composition containing ethylene and vinyl acetate; and (3) introducing at least a portion of the gaseous composition into a gas scrubbing tower and scrubbing the gaseous composition with acetic acid and water, thereby removing vinyl acetate from the gaseous composition, wherein the gas scrubbing tower has at least an outlet (A) and an outlet (B), wherein a liquid composition (α) discharged from the outlet (A) contains acetic acid and water, and the total content of acetic acid and water in the liquid composition (α) is 70% by mass or more, and a liquid composition (β) discharged from the outlet (B) contains vinyl acetate and acetic acid, and the total content of vinyl acetate and acetic acid in the liquid composition (β) is 90% by mass or more, and the water content is 10% by mass or less. [2] The production method according to [1], wherein the outlet (A) is located above the outlet (B). [3] The production method according to [1] or [2], wherein the gas washing tower has an inlet for acetic acid and an inlet for water, and the outlet (A) is located above the inlet for acetic acid and below the inlet for water. [4] The production method according to any one of [1] to [3], further comprising a step (4) of introducing the liquid composition (α) into an extraction tower and extracting acetic acid with vinyl acetate to separate the liquid composition into a liquid composition containing vinyl acetate and acetic acid and a liquid composition containing water. [5] The production method according to [4], wherein the liquid composition (α) and vinyl acetate are brought into countercurrent contact in the extraction tower to separate the liquid composition into a liquid composition containing vinyl acetate and acetic acid and a liquid composition containing water. [6] The production method according to [5], further comprising a step (5) of introducing the liquid composition (α) into a distillation column and distilling the liquid composition (α) into a distillation column.[8] The production method according to [7], further comprising a step of introducing the liquid composition (β) into the distillation column. [9] The production method according to [7] or [8], further comprising a step of introducing the liquid composition containing vinyl acetate and acetic acid separated in the step (4) into the distillation column.

[10] The production method according to any one of [7] to [9], wherein vinyl acetate, acetic acid, and water are separated in the distillation column.

[11] The production method according to

[10] , wherein the vinyl acetate obtained in the step (5) is optionally purified and then used in the step (4).

[12] The production method according to any one of [1] to

[11] , further comprising a step (6) of introducing the gaseous composition containing ethylene and carbon dioxide and a liquid composition containing vinyl acetate into a carbon dioxide removal system and separating the gaseous composition into ethylene and carbon dioxide, and using the ethylene separated in the step (6) in the step (1).

[0009] According to the production method of the present invention, the energy required for separating vinyl acetate, water, and acetic acid by distillation can be reduced, and an industrial production method of vinyl acetate with low energy consumption can be provided.

[0010] 1 is a schematic diagram of a vinyl acetate production apparatus used in Example 1. FIG. 2 is a schematic diagram of a vinyl acetate production apparatus used in Comparative Example 1.

[0011] The present invention relates to a method for producing vinyl acetate, comprising at least the steps of: (1) reacting ethylene, acetic acid, and oxygen to obtain a crude product containing vinyl acetate; (2) separating the crude product into a liquid composition containing vinyl acetate, acetic acid, and water and a gaseous composition containing ethylene and vinyl acetate; and (3) introducing at least a portion of the gaseous composition into a gas scrubbing tower and scrubbing the gaseous composition with acetic acid and water to remove vinyl acetate from the gaseous composition, wherein the gas scrubbing tower has at least outlets (A) and (B), wherein a liquid composition (α) discharged from outlet (A) contains acetic acid and water, and the total content of acetic acid and water in liquid composition (α) is 70% or more, and a liquid composition (β) discharged from outlet (B) contains vinyl acetate and acetic acid, and the total content of vinyl acetate and acetic acid in liquid composition (β) is 90% by mass or more.

[0012] In the production method of the present invention, vinyl acetate is produced by the Wacker process, whereby vinyl acetate is synthesized from ethylene, acetic acid, and oxygen as raw materials according to the following formula (I): ２ H ４ +CH ３ COOH + 1 / 2O ２ → CH ２ CHOCOCH ３ +H ２ O (I)

[0013] Step (1) is a step in which ethylene, acetic acid, and oxygen are reacted to obtain a crude product containing vinyl acetate. In a reactor, the vinyl acetate synthesis reaction represented by the above formula (I) proceeds by a gas-phase process using a heterogeneous catalyst. Ethylene, acetic acid, and oxygen are contacted with a fixed-bed catalyst containing palladium or a palladium compound and an alkali metal salt on a support material at a pressure of 0.1 to 3 MPa and a temperature of 130 to 200°C to produce vinyl acetate and water. The reaction is exothermic, and vinyl acetate is synthesized continuously. During this process, a side reaction represented by the following formula (II) also proceeds, in which a portion of the ethylene is oxidized by oxygen to produce carbon dioxide. As a result, the crude product removed from the reactor contains the reaction products vinyl acetate and water, the unreacted materials ethylene, acetic acid, and oxygen, and the by-product carbon dioxide. ２ H ４ +30 ２ → 2CO ２ +2H ２ O (II)

[0014] Step (2) is a step of separating the crude product obtained in step (1) into a liquid composition containing vinyl acetate, acetic acid, and water and a gaseous composition containing ethylene and vinyl acetate. The liquid composition may contain small amounts of other components. Furthermore, the gaseous composition typically contains carbon dioxide and oxygen in addition to ethylene and vinyl acetate, and may further contain gaseous water, acetic acid, and the like. The separation device for separating the liquid composition and the gaseous composition is not particularly limited, but continuous separation using a vertical gas separation column is preferred. In this case, it is preferred to supply acetic acid to the separation device, dissolve vinyl acetate and water in the acetic acid, and discharge a liquid composition containing vinyl acetate, acetic acid, and water from the separation device. Specifically, it is preferred to supply acetic acid from the top of the vertical separation column and discharge the liquid composition from the bottom. It is also preferred to further include a step of introducing the liquid composition thus separated in step (2) into a distillation column.

[0015] Step (3) is a step of removing vinyl acetate from the gaseous composition by introducing at least a portion of the gaseous composition obtained in step (2) into a gas scrubbing tower and scrubbing the gaseous composition with acetic acid and water. Removing vinyl acetate can prevent a decrease in the carbon dioxide removal capacity in the carbon dioxide removal system in step (6), which will be described later. The entire amount of the gaseous composition obtained in step (2) may be subjected to step (3), but as long as the concentration of carbon dioxide by-produced in step (1) does not increase too much, only a portion may be introduced into the gas scrubbing tower and supplied to the carbon dioxide removal system. Typically, 1 to 20 mass% of the gaseous composition obtained in step (2) may be introduced into the gas scrubbing tower.

[0016] The gas washing tower has two outlets, outlet (A) and outlet (B), and may have other outlets. The liquid composition after being used for gas washing is taken out from both outlet (A) and outlet (B). A liquid composition (α) is taken out from the outlet (A). The liquid composition (α) contains acetic acid and water, and the total content of acetic acid and water in the liquid composition (α) is 70% by mass or more. The total content of acetic acid and water is preferably 80% by mass or more, and more preferably 90% by mass or more. The liquid composition (α) mainly contains vinyl acetate in addition to acetic acid and water. Meanwhile, a liquid composition (β) is taken out from outlet (B). The liquid composition (β) contains vinyl acetate and acetic acid, and the total content of vinyl acetate and acetic acid in the liquid composition (β) is 90% by mass or more, and the water content is 10% by mass or less. By having the water content be 10% by mass or less, the energy required for distillation of the liquid composition (β) can be reduced. The water content is preferably 5% by mass, more preferably 2% by mass or less. Meanwhile, the total content of vinyl acetate and acetic acid is preferably 95% by mass or more, more preferably 98% by mass or more.

[0017] In the gas washing tower used in step (3), the outlet (A) is preferably located above the outlet (B). This allows the water content of the liquid composition (β) discharged from the outlet (B) to be reduced. The gas washing tower preferably has an inlet for acetic acid and an inlet for water, and the outlet (A) is preferably located above the inlet for acetic acid and below the inlet for water. This allows vinyl acetate in the gas to be dissolved in acetic acid and removed, and allows acetic acid contained in the gas after vinyl acetate removal to be dissolved in water and removed. As a result, a liquid composition (α) mainly composed of acetic acid and water is discharged from the outlet (A), which is located above the inlet for acetic acid and below the inlet for water. Furthermore, a liquid composition (β) mainly composed of vinyl acetate and acetic acid is discharged from the outlet (B), which is located below the outlet (A). It is preferable that the location where the gaseous composition obtained in step (2) is introduced into the gas washing tower be below the inlet for acetic acid, in consideration of the dissolution efficiency of vinyl acetate. Furthermore, the outlet (B) is preferably located below the location where the gaseous composition obtained in step (2) is introduced into the gas washing tower, and it is particularly preferred to provide it at the bottom of the tower. On the other hand, the position where the gas washed in the gas washing tower is taken out is preferably above the water inlet, and it is particularly preferred to provide it at the top of the tower. That is, in the gas washing tower, the following components are preferably arranged in this order from top to bottom: a washed gas outlet, a water inlet, the outlet (A), an acetic acid inlet, a pre-washed gas inlet, and the outlet (B). It is preferred that the method further comprises a step of introducing the liquid composition (β) thus taken out from the outlet (B) in step (3) into the distillation tower.

[0018] It is preferable that the method further includes step (4) of introducing the liquid composition (α) discharged from the outlet (A) of the gas scrubbing column in step (3) into an extraction column, extracting acetic acid with vinyl acetate, and separating the liquid composition into a liquid composition containing vinyl acetate and acetic acid, and a liquid composition containing water. The extraction column used in step (4) is not particularly limited as long as it is an extraction column capable of liquid-liquid extraction. The liquid composition (α) and liquid vinyl acetate are introduced into the extraction column, and the two are contacted in the liquid phase. As a result, acetic acid is extracted by vinyl acetate from the liquid composition (α) containing water and acetic acid as main components, and the liquid composition is separated into a liquid composition containing vinyl acetate and acetic acid, and a liquid composition containing water. It is preferable that the liquid composition (α) and vinyl acetate are brought into countercurrent contact in the extraction column, thereby separating the liquid composition into a liquid composition containing vinyl acetate and acetic acid, and a liquid composition containing water. Furthermore, it is more preferable to introduce the liquid composition (α) from the top of the extraction tower, introduce vinyl acetate from the bottom of the extraction tower, and bring the liquid composition (α) and vinyl acetate into countercurrent contact, withdraw a liquid composition containing vinyl acetate and acetic acid from the top of the extraction tower, and withdraw a liquid composition containing water from the bottom of the extraction tower. This configuration is preferably adopted because the specific gravity of the aqueous phase is higher than that of the oil phase. It is preferable to further include a step of introducing the liquid composition containing vinyl acetate and acetic acid separated in step (4) into a distillation tower. The total content of vinyl acetate and acetic acid in the liquid composition containing vinyl acetate and acetic acid is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more. The content of water in the liquid composition containing water is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0019] Preferably, the method further includes step (5), in which the liquid composition separated in step (2) is introduced into a distillation column and distilled. In this case, it is preferable to introduce the liquid composition (β) removed from outlet (B) in step (3) into the distillation column, and it is also preferable to introduce the liquid composition containing vinyl acetate and acetic acid separated in step (4) into the distillation column. It is more preferable to subject the liquid composition separated in step (2), liquid composition (β), and the liquid composition separated in step (4) to distillation step (5). A vinyl acetate fraction, a water fraction, and an acetic acid fraction are obtained by distillation from a mixture containing vinyl acetate, acetic acid, and water. Small amounts of other components may be contained in each fraction. According to a preferred production method of the present invention, most of the water used for gas scrubbing in step (3) can be removed by liquid-liquid extraction in step (4). This allows the aqueous and oil phases to be separated with almost no energy required by phase separation, thereby reducing the amount of water evaporated in the distillation in step (5). As a result, energy consumption can be reduced. If steam is used as a heat source, the amount of steam required can be reduced. It is also preferred that the vinyl acetate obtained in step (5) is optionally purified before being used to extract acetic acid in step (4).

[0020] Preferably, step (3) further comprises step (6), in which the gaseous composition is washed with acetic acid and water to separate it into a gaseous composition containing ethylene and carbon dioxide and a liquid composition containing vinyl acetate, and then the gaseous composition containing ethylene and carbon dioxide is introduced into a carbon dioxide removal system to separate it into ethylene and carbon dioxide. It is also preferable that the ethylene separated in step (6) is introduced into the reactor of step (1) and used in the vinyl acetate synthesis reaction. When a portion of the gaseous composition discharged from the separation device of step (2) is subjected to step (3) and the subsequent step (6), it is preferable that the ethylene separated in step (6) is combined with the remainder of the gaseous composition discharged from the separation device of step (2), and after adding ethylene, acetic acid, and oxygen, the ethylene is introduced into the reactor of step (1) and used in the vinyl acetate synthesis reaction. By recycling the gaseous composition containing unreacted raw materials in this manner, vinyl acetate can be produced efficiently and without waste.

[0021] Example 1 Vinyl acetate was produced using the apparatus shown in Figure 1. A circulating gas containing ethylene was introduced into acetic acid evaporator 1 through conduit 11, and acetic acid vaporized in acetic acid evaporator 1 was mixed with the circulating gas and discharged through conduit 12. Oxygen was supplied to the circulating gas through conduit 12, and the gas was then introduced into reactor 2. After the vinyl acetate synthesis reaction had progressed in reactor 2, a crude product was discharged through conduit 13. The crude product contained vinyl acetate and water produced by the reaction in reactor 2, unreacted ethylene, acetic acid, and oxygen, as well as carbon dioxide as a by-product.

[0022] The crude product was introduced into gas separation column 3 via conduit 13, and liquid acetic acid was introduced from the top of the column and brought into contact with the gas, thereby separating the crude product into a liquid composition containing vinyl acetate, acetic acid, and water, and a gaseous composition containing ethylene, oxygen, carbon dioxide, vinyl acetate, acetic acid, and water. The resulting liquid composition was introduced into distillation column 4 via conduit 14. The gaseous composition was also introduced into compressor 5 via conduit 15, and the gaseous composition compressed by compressor 5 was discharged into conduit 16. Approximately 95 mass% of the gaseous composition was supplied via conduit 16 to conduit 11, and the remaining approximately 5 mass% was supplied to conduit 17.

[0023] The approximately 5% by mass gaseous composition was introduced into the lower part of the gas scrubbing tower 6 through a conduit 17. In the gas scrubbing tower 6, water was supplied through an inlet, and acetic acid was supplied through an inlet below the inlet. A liquid composition (α) containing acetic acid and water was extracted into a conduit 20 through an outlet (A) located between the water inlet and the acetic acid inlet. A liquid composition (β) containing vinyl acetate and acetic acid was extracted into a conduit 21 through an outlet (B) located at the bottom of the gas scrubbing tower 6. A gaseous composition containing ethylene, carbon dioxide, and oxygen was extracted from the upper part of the gas scrubbing tower 6 through a conduit 18. The total content of acetic acid and water in the liquid composition (α) was approximately 100% by mass, and the total content of vinyl acetate and acetic acid in the liquid composition (β) was approximately 99% by mass, with the water content being approximately 1% by mass. The gas scrubbing tower 6 had, from top to bottom, an outlet for the gaseous composition, an inlet for water, an outlet (A), an inlet for acetic acid, an inlet for the gaseous composition, and an outlet (B).

[0024] The gaseous composition removed from the gas scrubber 6 is passed through a conduit 18 to a CO ２The gaseous composition was introduced into removal system 7, where carbon dioxide was removed, and then introduced into conduit 11. Ethylene was also introduced into conduit 11, and then returned to acetic acid evaporator 1. That is, most of the gaseous composition was circulated from acetic acid evaporator 1 to acetic acid evaporator 1 through conduits 12, 13, 15, 16, and 11. The remaining portion of the gaseous composition was circulated through conduits 17, 18, 19, and 11, where carbon dioxide was removed and the remaining portion was returned to acetic acid evaporator 1. This makes it possible to prevent carbon dioxide, a by-product, from accumulating in the circulating gas and increasing its concentration.

[0025] The liquid composition (β) removed from the gas scrubbing column 6 was introduced into the distillation column 4 via a conduit 21. The liquid composition (α) removed from the gas scrubbing column 6 was introduced into the upper part of the acetic acid extraction column 8 via a conduit 20. The acetic acid extraction column 8 was a tower-type liquid-liquid extraction apparatus, and had, from the top, an outlet for the liquid composition containing vinyl acetate and acetic acid, an inlet for the liquid composition (α), an inlet for vinyl acetate, and an outlet for the liquid composition containing water.

[0026] A liquid composition (α) containing acetic acid and water was supplied to the top of acetic acid extraction column 8 via conduit 20, and vinyl acetate (liquid) was supplied to the bottom of acetic acid extraction column 8 via conduit 23. The vinyl acetate was obtained from distillation column 4. Because the density of liquid composition (α) was higher than that of vinyl acetate, liquid composition (α) settled and vinyl acetate rose, and the two were in countercurrent contact within acetic acid extraction column 8. Since acetic acid is more soluble in vinyl acetate than water, acetic acid dissolved in the rising vinyl acetate. As a result, a liquid composition containing vinyl acetate and acetic acid was extracted from the top of acetic acid extraction column 8 and supplied to distillation column 4 via conduit 24. A liquid composition containing water was extracted from the bottom of acetic acid extraction column 8. The total content of vinyl acetate and acetic acid in the liquid composition containing vinyl acetate and acetic acid was approximately 99% by mass, and the water content in the liquid composition containing water was approximately 97% by mass.

[0027] A liquid composition containing vinyl acetate, acetic acid, and water was introduced into distillation column 4 via conduits 14, 21, and 24, and the vinyl acetate, acetic acid, and water were separated by distillation. The vinyl acetate obtained by distillation was withdrawn via conduit 22, and a portion of it was supplied to acetic acid extraction column 8 via conduit 23. During continuous operation, the amount of steam required in distillation column 4 was 16.2 ton / h.

[0028] Comparative Example 1 Vinyl acetate was produced using the apparatus shown in Figure 2. Vinyl acetate was continuously produced using the same apparatus as in Example 1, except that it did not have acetic acid extraction column 8. Since it did not have acetic acid extraction column 8, it also did not have conduit 20 connecting gas scrubbing column 6 and acetic acid extraction column 8, conduit 24 connecting acetic acid extraction column 8 and distillation column 4, or conduit 23 connecting conduit 22 and acetic acid extraction column 8.

[0029] In the gas washing tower 6, water and acetic acid were supplied from their respective inlets in the same manner as in Example 1, and the gaseous composition was supplied to the gas washing tower 6 through a conduit 18. ２ The gas was introduced into the gas removal system 7. Meanwhile, the entire amount of the liquid composition obtained in the gas scrubbing tower 6 was taken out into the conduit 21 from an outlet located at the bottom of the gas scrubbing tower 6. The liquid composition contained vinyl acetate, acetic acid, and water, and the total content of vinyl acetate and acetic acid was about 85% by mass, and the water content was about 15% by mass. The gas scrubbing tower 6 had, from top to bottom, an outlet for the gaseous composition, an inlet for water, an inlet for acetic acid, an inlet for the gaseous composition, and an outlet for the liquid composition. The feed rates of water and acetic acid were the same as in Example 1.

[0030] The liquid composition was introduced into distillation column 4 from the outlet of gas scrubbing column 6 via conduit 21. In addition, the liquid composition was introduced into distillation column 4 from gas separation column 3 via conduit 14. Distillation was carried out in distillation column 4 to separate vinyl acetate, acetic acid, and water. During continuous operation, the amount of steam required in distillation column 4 was 18.0 ton / h. Because the amount of water to be separated in distillation column 4 was large, more steam was required than in Example 1.

[0031] 1 Acetic acid evaporator 2 Reactor 3 Gas separation column 4 Distillation column 5 Compressor 6 Gas scrubbing column 7 CO２ Removal system 8 Acetic acid extraction tower 11-24 Conduit

Claims

1. A method for producing vinyl acetate comprising at least the steps of: (1) reacting ethylene, acetic acid and oxygen to obtain a crude product containing vinyl acetate; (2) separating the crude product into a liquid composition containing vinyl acetate, acetic acid and water and a gaseous composition containing ethylene and vinyl acetate; and (3) introducing at least a portion of the gaseous composition into a gas washing tower and washing the gaseous composition with acetic acid and water, thereby removing vinyl acetate from the gaseous composition, wherein the gas washing tower has at least an outlet (A) and an outlet (B), a liquid composition (α) discharged from the outlet (A) contains acetic acid and water, and the total content of acetic acid and water in the liquid composition (α) is 70 mass% or more, and a liquid composition (β) discharged from the outlet (B) contains vinyl acetate and acetic acid, and the total content of vinyl acetate and acetic acid in the liquid composition (β) is 90 mass% or more and the water content is 10 mass% or less.

2. The manufacturing method according to claim 1, wherein the outlet (A) is located above the outlet (B).

3. The method according to claim 1 or 2, wherein the gas washing tower has an inlet for acetic acid and an inlet for water, and the outlet (A) is located above the inlet for acetic acid and below the inlet for water.

4. The method according to claim 1 or 2, further comprising a step (4) of introducing the liquid composition (α) into an extraction tower, extracting acetic acid with vinyl acetate, and separating the liquid composition into a liquid composition containing vinyl acetate and acetic acid and a liquid composition containing water.

5. The production method according to claim 4, wherein the liquid composition (α) and vinyl acetate are countercurrently contacted in the extraction tower to separate the liquid composition into a liquid composition containing vinyl acetate and acetic acid and a liquid composition containing water.

6. The production method according to claim 5, wherein the liquid composition (α) is introduced from an upper portion of the extraction tower, vinyl acetate is introduced from a lower portion of the extraction tower, and the liquid composition (α) and vinyl acetate are brought into countercurrent contact with each other, a liquid composition containing vinyl acetate and acetic acid is taken out from the upper portion of the extraction tower, and a liquid composition containing water is taken out from the lower portion of the extraction tower.

7. The method according to claim 1 or 2, further comprising a step (5) of introducing the liquid composition separated in the step (2) into a distillation column and distilling it.

8. The method according to claim 7, further comprising the step of introducing the liquid composition (β) into the distillation column.

9. The method according to claim 7, further comprising the step of introducing the liquid composition containing vinyl acetate and acetic acid separated in step (4) into the distillation column.

10. The process according to claim 7, wherein vinyl acetate, acetic acid, and water are separated in the distillation column.

11. The process according to claim 10, wherein the vinyl acetate obtained in step (5) is used in step (4) after optionally being purified.

12. The production method according to claim 1 or 2, further comprising a step (6) of separating the gaseous composition containing ethylene and carbon dioxide and a liquid composition containing vinyl acetate in the step (3) by washing the gaseous composition with acetic acid and water, and introducing the gaseous composition containing ethylene and carbon dioxide into a carbon dioxide removal system and separating it into ethylene and carbon dioxide, and using the ethylene separated in the step (6) in the step (1).

Images