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EP0361785A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Removal of iodine or iodide impurities

Assignee: BP Chemicals Ltd
•
Filing: 1989-09-21
•
Granted: —
•
Expires: 2009-09-21
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Abstract

Abstract A process for removing iodine or soluble iodide impurities from a carboxylic acid or carboxylic acid anhydride, the carboxylic acid or carboxylic acid anhydride having been produced by a carbonylation process, comprises step (a) treating impure carboxylic acid or carboxylic acid anhydride containing iodine or soluble iodide impurities with an unsupported scavenger at a temperature of between 20 and 250°C and step (b) thereafter separating the treated carboxylic acid or carboxylic acid anhydride from the scavenger characterised in that the scavenger consists of a silver salt in the absence of a trialkyl phosphine, a triaryl phosphine and a heterocyclic aromatic nitrogen compound. The preferred scavenger for acetic acid and acetic anhydride is silver acetate.

Inventors

  • 👤 Benjamin Patrick Bp Chemicals Limited Gracey

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-31 21:20
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/54; C07C51/573; C07C51/42; C07C51/487; Y; Y10; Y10S; Y10S203/00; Y10S203/06

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 104 words
A process for removing iodine or soluble iodide impurities from a carboxylic acid or carboxylic acid anhydride, the carboxylic acid or carboxylic acid anhydride having been produced by a carbonylation process, which process comprises step (a) treating impure carboxylic acid or carboxylic acid anhydride containing iodine or soluble iodide impurities with an unsupported scavenger at a temperature of between 20 and 250°C and step (b) thereafter separating the treated carboxylic acid or carboxylic acid anhydride from the scavenger characterised in that the scavenger consists of a silver salt in the absence of a trialkyl phosphine, a triaryl phosphine and a heterocyclic aromatic nitrogen compound.
Claim 2
Dependent Claim 104 words
A process for removing iodine or soluble iodide impurities from a carboxylic acid or carboxylic acid anhydride, the carboxylic acid or carboxylic acid anhydride having been produced by a carbonylation process, which process comprises step (a) treating impure carboxylic acid or carboxylic acid anhydride containing iodine or soluble iodide impurities with an unsupported scavenger at a temperature of between 20 and 250°C and step (b) thereafter separating the treated carboxylic acid or carboxylic acid anhydride from the scavenger characterised in that the scavenger consists of a silver salt in the absence of a trialkyl phosphine, a triaryl phosphine and a heterocyclic aromatic nitrogen compound.
Claim 3
Dependent Claim 23 words
A process as claimed in claim 1 wherein the silver salt has an anion corresponding to the carboxylic acid or carboxylic acid anhydride.
Claim 4
Dependent Claim 14 words
A process as claimed in claim 1 wherein the silver salt is silver acetate.
Claim 5
Dependent Claim 38 words
A process as claimed in any one of claims 1 to 3 wherein the impure carboxylic acid or carboxylic acid anhydride contains at least 300 parts per million by weight in total of iodine and soluble iodide impurities.
Claim 6
Dependent Claim 33 words
A process as claimed in claim 4 wherein the treated carboxylic acid or carboxylic acid anhydride contains less than 100 parts per billion by weight in total of iodine and soluble iodide impurities.
Claim 7
Dependent Claim 34 words
A process as claimed in any one of claims 1 to 5 wherein the carboxylic acid or carboxylic acid anhydride is chosen from the group consisting of acetic acid, propionic acid and acetic anhydride.
Claim 8
Dependent Claim 23 words
A process as claimed in claim 1 wherein the step (a) is carried out at a temperature in the range 80 - 150°C.
Claim 9
Dependent Claim 35 words
A process as claimed in claim 1 wherein the impure carboxylic acid or carboxylic acid anhydride is treated with an unsupported scavenger for a period of time in the range from 10 to 100 minutes.

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