Method for producing acetic acid

Patent metadata

Field	Value
Publication number	US-10428003-B2
Application number	US-201715540172-A
Country	US
Kind code	B2
Filing date	May 25, 2017
Priority date	Jan 18, 2017
Publication date	Oct 1, 2019
Grant date	Oct 1, 2019

Abstract

It is intended to provide an acetic acid production method capable of industrially advantageously separating and removing a by-product acetaldehyde in the separation step of separating a process stream into aqueous and organic phases. In the present invention, the separation step satisfies, for example, the following conditions (vi) to (viii), and at least a portion of the aqueous phase is treated in the acetaldehyde separation and removal step: (vi) acetaldehyde concentrations in the aqueous and/or organic phases are not more than 28.1 mass % and not more than 24.8 mass %, respectively; (vii) a separation temperature is not more than 70° C.; and (viii) methyl acetate concentrations in the aqueous and/or organic phases are not more than 12.0 mass % and not more than 47.6 mass %, respectively, and/or the sum of the methyl acetate concentrations in the aqueous and organic phases is not more than 59.6 mass %.

First claim

The invention claimed is:

1. A method for producing acetic acid by reacting methanol with carbon monoxide in the presence of a catalyst system comprising a metal catalyst and methyl iodide, acetic acid, methyl acetate, and water, the method comprising:
separating a process stream containing at least water, acetic acid, methyl iodide, and acetaldehyde into an aqueous phase and an organic phase, wherein an acetaldehyde concentration in a liquid to be subjected to the separation is not less than 0.026% by mass and a methyl acetate concentration in the liquid to be subjected to the separation step is 2.0 to 50% by mass, wherein
the following condition (i), the following condition (ii), the following condition (iii), and at least one of the following conditions (iv) and (v) are satisfied:
(i) an acetaldehyde concentration in the aqueous phase is not less than 0.045% by mass, and/or an acetaldehyde concentration in the organic phase is not less than 0.013% by mass;
(ii) a temperature at the time of the separation is not less than −5° C.;
(iii) a methyl acetate concentration in the organic phase is 5.8% to 60% by mass;
(iv) an acetaldehyde distribution coefficient [{acetaldehyde concentration (% by mass) of the aqueous phase}/{acetaldehyde concentration (% by mass) of the organic phase}] is not more than 4.1; and
(v) a methyl acetate distribution coefficient [{methyl acetate concentration (% by mass) of the aqueous phase}/{methyl acetate concentration (% by mass) of the organic phase}] is not more than 0.53; and
separating and removing the acetaldehyde derived from the process stream, wherein at least a portion of the organic phase is treated.

2. The method for producing acetic acid according to claim 1 , wherein the catalyst system further comprises an ionic iodide.

3. The method for producing acetic acid according to claim 1 , wherein all of the conditions (i), (ii), (iii), (iv), and (v) are satisfied.

4. A method for producing acetic acid, comprising:
carbonylating methanol with carbon monoxide in the presence of a catalyst system comprising a metal catalyst and methyl iodide, acetic acid, methyl acetate, and water in a reaction vessel to produce acetic acid;
evaporating a reaction mixture obtained by the carbonylation to separate into a vapor stream and a residual liquid stream in an evaporator;
removing a lower boiling point component by distillation to separate the vapor stream into an overhead stream rich in at least one lower boiling point component selected from methyl iodide and acetaldehyde and an acetic acid stream rich in acetic acid;
separating a process stream containing at least water, acetic acid, methyl iodide, and acetaldehyde into an aqueous phase and an organic phase, wherein an acetaldehyde concentration in a liquid to be subjected to the separation is not more than 26.0% by mass and a methyl acetate concentration in the liquid to be subjected to the separation step is not more than 38.2% by mass, wherein
the following condition (vi), the following condition (vii), the following condition (viii), and at least one of the following conditions (ix) and (x) are satisfied:
(vi) an acetaldehyde concentration in the aqueous phase is not more than 28.1% by mass, and/or an acetaldehyde concentration in the organic phase is not more than 24.8% by mass;
(vii) a temperature at the time of the separation is not more than 70° C.;
(viii) a methyl acetate concentration in the aqueous phase is 5.0% to 12.0% by mass, and/or a methyl acetate concentration in the organic phase is 8.0% to 47.6% by mass, and/or the sum of the methyl acetate concentration in the aqueous phase and the methyl acetate concentration in the organic phase is 15% to 59.6% by mass;
(ix) an acetaldehyde distribution coefficient [{acetaldehyde concentration (% by mass) of the aqueous phase}/{acetaldehyde concentration (% by mass) of the organic phase}] is 1.1 to 4.5; and
(x) a methyl acetate distribution coefficient [{methyl acetate concentration (% by mass) of the aqueous phase}/{methyl acetate concentration (% by mass) of the organic phase}] is 0.25 to 0.53; and
separating and removing the acetaldehyde derived from the process stream, wherein at least a portion of the aqueous phase is treated.

5. The method for producing acetic acid according to claim 4 , wherein the catalyst system further comprises an ionic iodide.

6. The method for producing acetic acid according to claim 4 , wherein all of the conditions (vi), (vii), (viii), (ix), and (x) are satisfied.

7. A method for producing acetic acid by reacting methanol with carbon monoxide in the presence of a catalyst system comprising a metal catalyst and methyl iodide, acetic acid, methyl acetate, and water, the method comprising
separating a process stream containing at least water, acetic acid, methyl iodide, and acetaldehyde into an aqueous phase and an organic phase, wherein an acetaldehyde concentration in a liquid to be subjected to the separation is not more than 26.0% by mass and a methyl acetate concentration in the liquid to be subjected to the separation step is not more than 38.2% by mass, wherein
the following condition (vi), the following condition (vii), the following condition (viii), and at least one of the following conditions (ix) and (x) are satisfied:
(vi) an acetaldehyde concentration in the aqueous phase is not more than 28.1% by mass, and/or an acetaldehyde concentration in the organic phase is not more than 24.8% by mass;
(vii) a temperature at the time of the separation is not more than 70° C.;
(viii) a methyl acetate concentration in the aqueous phase is 5.0% to 12.0% by mass, and/or a methyl acetate concentration in the organic phase is 8.0% to 47.6% by mass, and/or the sum of the methyl acetate concentration in the aqueous phase and the methyl acetate concentration in the organic phase is 14% to 59.6% by mass;
(ix) an acetaldehyde distribution coefficient [{acetaldehyde concentration (% by mass) of the aqueous phase}/{acetaldehyde concentration (% by mass) of the organic phase}] is 1.1 to 4.5; and
(x) a methyl acetate distribution coefficient [{methyl acetate concentration (% by mass) of the aqueous phase}/{methyl acetate concentration (% by mass) of the organic phase}] is 0.25 to 0.53; and
separating and removing the acetaldehyde derived from the process stream, wherein at least a portion of the aqueous phase is treated.

8. The method for producing acetic acid according to claim 7 , wherein the catalyst system further comprises an ionic iodide.

9. The method for producing acetic acid according to claim 7 , wherein all of the conditions (vi), (vii), (viii), (ix), and (x) are satisfied.

10. The method for producing acetic acid according to claim 1 , further comprising separating offgas from the process into a stream rich in carbon monoxide and a stream rich in acetic acid by absorption treatment with an absorption solvent containing at least acetic acid.

11. The method for producing acetic acid according to claim 1 , wherein in the condition (iv), the acetaldehyde distribution coefficient is 0.6 to 3.35.

12. The method for producing acetic acid according to claim 1 , wherein in the condition (v), the methyl acetate distribution coefficient is 0.20 to 0.44.

13. The method for producing acetic acid according to claim 4 , wherein the acetaldehyde concentration in the liquid to be subjected to the separation is 0.057 to 10% by mass.

14. The method for producing acetic acid according to claim 4 , wherein the methyl acetate concentration in the liquid to be subjected to the separation is 5.0 to 31% by mass.

15. The method for producing acetic acid accordi

Assignees

• Daicel Corp

Inventors

• Shimizu Masahiko
• Goda Susumu
• Miura Hiroyuki

Classifications

• C07C45/80

  by liquid-liquid treatment · CPC title

• B01D3/009

  in combination with chemical reactions · CPC title

• B01D15/362

  Cation-exchange · CPC title

• B01D3/143

  by two or more of a fractionation, separation or rectification step · CPC title

• C07C51/445

  by steam distillation · CPC title