Continuous production of aromatic carboxylic acids

• US 5,087,741 A
• Filed: 11/29/1990
• Issued: 02/11/1992
• Est. Priority Date: 11/29/1990
• Status: Expired due to Term

• Current Assignee: Grupo Petrotemex SA DE CV (Grupo Petrotemex)
• Original Assignee: Eastman Kodak Company
• Inventors: Bryson, Terry D., Tennant, Brent A.
• Primary Examiner(s): Dees, Jose G.
• Assistant Examiner(s): CLARKE, VERA
• Application Number:
  US07/619,568
• Time in Patent Office: 439 Days
• Field of Search: 562/413, 562/414, 562/416
• US Class Current: 562/414
• CPC Class Codes: C07C 51/265 having alkyl side chains which are oxidised to carboxyl groups
• CPC Class Codes: C07C 63/26 1,4 - Benzenedicarboxylic acid

Abstract

Disclosed is an improved process for the continuous production of aromatic carboxylic acids such as terephthalic acid by the liquid-phase oxidation of an alkyl aromatic compound using an oxygen-containing gas. Operation of the process is improved by providing a spray of recycled reaction medium at or near the top of a columnar oxidation vessel to minimize entrainment of liquid and/or solid components of the reactor in the process off-gas.

Claims

1. Method for the continuous production of an aromatic carboxylic acid in a pressurized oxidation reactor by liquid-phase, exothermic oxidation of an alkyl aromatic compound with an oxygen-containing gas in the presence of an oxidation catalyst and aqueous C₂ to C₆ aliphatic, monocarboxylic acid reaction medium which comprises the steps of:

(1) continuously feeding to the reactor the alkyl aromatic compound, the aqueous, monocarboxylic acid reaction medium having the oxidation catalyst dissolved therein and an oxygen-containing gas;

(2) continuously removing from the lower portion of the reactor an oxidizer product comprising the aromatic carboxylic acid and the aqueous, monocarboxylic acid reaction medium having the oxidation catalyst dissolved therein;

(3) continuously removing from the upper portion of the reactor oxygen-depleted gas and vaporized aqueous, monocarboxylic acid reaction medium;

(4) condensing from the stream of step (3) the aqueous, monocarboxylic acid reaction medium; and

(5) returning at least a portion of the condensed, aqueous, monocarboxylic acid reaction medium obtained in step (4) in the form of a spray between the top of the gas/liquid contents of the reactor and the point within the reactor which the stream of (3) is removed.

2. Method according to claim 1 wherein the aromatic carboxylic is a benzene dicarboxylic acid, the alkyl aromatic compound is xylene and the monocarboxylic acid is acetic acid.

3. Method for the continuous production of terephthalic acid in a pressurized oxidation reactor by liquid-phase, exothermic oxidation of p-xylene with an oxygen-containing gas in the presence of an oxidation catalyst and aqueous acetic acid reaction medium which comprises the steps of:

(1) continuously feeding to the reactor p-xylene, aqueous, acetic acid reaction medium having the oxidation catalyst dissolved therein and an oxygen-containing gas;

(2) continuously removing from the lower portion of the reactor an oxidizer product comprising terephthalic acid and aqueous acetic acid reaction medium having the oxidation catalyst dissolved therein;

(3) continuously removing from the upper portion of the reactor oxygen-depleted gas and vaporized aqueous, acetic acid reaction medium;

(4) condensing from the stream (3) aqueous, acetic acid reaction medium; and

(5) returning 10 to 100% of the condensed, aqueous, acetic acid reaction medium obtained in step (4) in the form of a spray between the top of the gas/liquid contents of the reactor and the point within the reactor which the stream of step (3) is removed.