Celanese International Corporation

David A Trueba

Mark O Scates

Raymond J Zinobile

Shrikant Kulkarni

Wayne David Picard

Jose J Arturo Talancon

Jose J Talancon

Shrikant U Kulkarni

An improvement of the methanol carbonylation process for manufacturing acetic acid is disclosed. Specifically disclosed is a method for reducing the formation of alkyl iodides and Ccarboxylic acids by removing permanganate reducing compounds ('PRC's') from the light phase of the condensed light ends overhead stream, including (a) distilling the light phase to yield a PRC enriched overhead stream; and (b) extracting the third overhead stream with water in at least two consecutive stages and separating therefrom one or more aqueous streams containing PRC&#x2033;s.

Removal of permanganate reducing compounds from methanol carbonylation process stream

Disclosed is a method of controlling a separation process for removing permanganate reducing compounds from a process stream in the methanol carbonylation process for making acetic acid, where the method includes the steps of measuring the density of a stream containing acetaldehyde and methyl iodide, optionally calculating the relative concentrations of acetaldehyde and methyl iodide in the stream, and adjusting distillation or extraction process parameters based on the measured density or one or more relative concentrations calculated therefrom.

Control method for process of removing permanganate reducing compounds from methanol carbonylation process

An improvement of the methanol carbonylation process for manufacturing acetic acid is disclosed. Specifically disclosed is a method for removing permanganate reducing compounds ('PRC's') from the condensed light ends overhead stream, including (a) distilling at least a portion of the condensed light ends overhead to yield a PRC enriched second overhead stream; (b) extracting the second overhead stream with water and separating therefrom an aqueous stream containing PRC's; and (c) returning at least a portion of the extracted second overhead to the second distiller.

An improvement of the methanol carbonylation process for manufacturing acetic acid is disclosed. Specifically disclosed is a method for reducing the formation of alkyl iodides and Ccarboxylic acids by removing permanganate reducing compounds ('PRC's') from the light phase of the condensed light ends overhead stream, including (a) distilling the light phase to yield a PRC enriched overhead stream; and (b) extracting the third overhead stream with water in at least two consecutive stages and separating therefrom one or more aqueous streams containing PRC's.

An improved process is disclosed for producing acetic acid, including the following steps: reacting a carbonylatable reactant such as methanol, methyl acetate, methyl formate or dimethyl ether with carbon monoxide in a reaction medium containing water, methyl iodide, and a catalyst to produce a reaction product that contains acetic acid; separating the reaction product to provide a volatile phase containing acetic acid, water, and methyl iodide and a less volatile phase; distilling the volatile phase to produce a purified acetic acid product and a first overhead containing water, methyl acetate, and methyl iodide; phase separating the first overhead to provide a first liquid phase containing water and a second liquid phase containing methyl iodide; and adding dimethyl ether to the process in an amount effective to enhance separation of the first overhead to form the first and second liquid phases.

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Webster, TX, United States of America

David A Trueba