US 10,246,399 B2Granted

Process for producing acetic acid

AssigneeDaicel Corporation

InventorsMasahiko Shimizu, Yoshihisa Mizutani, Hiroyuki Miura

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Abstract

A process for producing acetic acid comprises a process comprising: (1) carbonylating methanol; (2) separating the reaction mixture into a volatile phase and a less-volatile phase; (3) distilling the volatile phase to form a first overhead rich in a lower boiling component, and an acetic acid stream rich in acetic acid; and at least one step group selected from the group consisting of the following sections (4), (9), and (15): (4) a section for separating impurities from the acetic acid stream to give purified acetic acid, (9) a section for separating the first overhead into a stream rich in acetaldehyde and a stream rich in methyl iodide, and (15) a section for absorption-treating an off-gas from the process with an absorption solvent and forming a carbon monoxide-rich stream and an acetic acid-rich stream. In this process, the concentration of oxygen in a gaseous phase of the process is controlled to less than 7% by volume and/or the concentration of oxygen in a liquid phase of the process is controlled to less than 7×10−5 g/g, and the formation of iodine is reduced. The process effectively reduces or prevents local corrosion of an inner wall of a process unit and/or line.

Claims14

Dependent claims

A process for producing acetic acid, comprising:

(1) allowing methanol to carbonylation react with carbon monoxide in the presence of a catalyst system, acetic acid, methyl acetate, and water, wherein the catalyst system comprises a metal catalyst, an ionic metal iodide, and methyl iodide;
(2) separating the reaction mixture into a volatile phase and a less-volatile phase;
(3) distilling the volatile phase to form a first overhead and an acetic acid stream, wherein the first overhead is rich in at least one lower boiling component selected from the group consisting of methyl iodide and acetaldehyde, and the acetic acid stream is rich in acetic acid;
and
at least one section selected from the group consisting of the following sections (4), (9), and (15):
(4) a purification section for obtaining purified acetic acid from the acetic acid stream;
(9) a separation section for separating at least acetaldehyde from the first overhead;
and
(15) an off-gas treatment section for absorption-treating an off-gas from the process with an absorption solvent and forming a carbon monoxide-rich stream and an acetic acid-rich stream;
wherein a concentration of oxygen is controlled in at least one selected from the group consisting of the following (a) and (b):
(a) the concentration of oxygen in a gaseous phase of the process is controlled to less than 7% by volume,
(b) the concentration of oxygen in a liquid phase of the process is controlled to less than 7×10−5 g/g.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/577,524Filed 17 Nov 2017
Priority: JP 2017-0207757 Feb 2017
Published: US 2018/0354884 A113 Dec 2018
Granted: 2 Apr 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

C07C 51/44
By change of the physical state, e.g. crystallisation: by distillation
B01D 3/143
Fractional distillation or use of a fractionation or rectification column: by two or more of a fractionation, separation or rectification step
B01D 15/361
Involving ionic interaction, e.g. ion-exchange, ion-pair, ion-suppression or ion-exclusion: ion-exchange
B01J 27/08
Halogens; Compounds thereof: halides

Family

US 2018/0354884 A1Pre-grant publication · published 13 Dec 2018
US 10,246,399 B2This patent

From the US filing history. Foreign family members aren’t listed.

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