Celanese International Corporation

Hoechst Celanese Corporation

Wayne David Picard

Mark O Scates

Ronald David Shaver

Nathan Kirk Powell

George A Blay

Fred Ronald Olsson

Madan Singh

Ismael Torres Tejeda

Nathan Jeremy Nagel

R Jay Warner

G Paull Torrence

Raymond J Zinobile

Melchior A Meilchen

Stephen Charles Webb

David A Trueba

Valerie Santillan

Michael L Karnilaw

Robin Suzanne Tanke

Duane Lyle Usrey

Richard F Vogel, Jr

Jose J Arturo Talancon

Jose J Talancon

An improved apparatus and method of producing acetic acid includes condensing overhead vapor to provide reflux to the light ends column as well as condensing vapor from a central portion of the light ends column to increase capacity. Throughput or load on the light ends column is substantially reduced without compromising product quality.

Method and apparatus for making acetic acid with improved light ends column productivity

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.

Removal of permanganate reducing compounds from methanol carbonylation process stream

The present invention is directed to using methyl acetate from a vinyl acetate-based or a vinyl-or ethylene-alcohol based polymer or copolymer process directly for use in a methanol carbonylation production process to produce acetic acid, acetic anhydride, or a coproduction of each. Methyl acetate is a by-product of commercial polyvinyl-alcohol or alkene vinyl alcohol copolymer-based processes. Generally, this material is processed to recover methanol and acetic acid. Discussed herein is a cost-saving scheme to by-pass the methyl acetate processing at production or plant facilities and utilize the methyl acetate in an integrated methanol carbonylation unit. The scheme discussed eliminates an expensive hydrolysis step often associated with the polymer process.

Integrated process for producing carbonylation acetic acid, acetic anhydride, or coproduction of each from a methyl acetate by-product stream

Disclosed is a method to manufacture high purity acetic acid. Although described in relation to that produced by a low water carbonylation process the present invention is applicable to other mechanisms for production of acetic acid which results in formation of permanganate reducing compounds such as acetaldehyde, propionic acid, and alkyl iodide impurities in intermediate process streams. It has been found that permanganate reducing compounds and alkyl iodides may be conveniently removed from a light phase of an intermediate stream in the reaction process by employing a multiple distillation process coupled with an optional extraction of acetaldehyde. The distillation process involves first distilling a light phase to concentrate the permanganate reducing compounds, and in particular the acetaldehyde, and then separating the permanganate reducing compounds and alkyl iodides in a second distillation tower. The second distillation serves to remove the permanganate reducing compounds and alkyl iodides from methyl iodide, methyl acetate, and methanol mixture. As an optional third step, the twice distilled stream may be directed to an extractor to remove any remaining quantities of methyl iodide from the aqueous acetaldehyde stream to obtain acetic acid as a final product in greater than 99% purity. It has been found that this process removes at least 50% of the permanganate reducing compounds and alkyl iodides and at least 20% of the propionic acid impurity from the intermediate light phase stream, and results in lower alkyl iodide concentration in the carbonylation reaction process, and in particular in the carbonylation reactor. It has also been found that during shut down of the inventive process, polymers of acetaldehyde tend to form in the base of the second distillation tower. To avoid or minimize the formation of these polymers, a constant flow of solvent is passed through the base of the column.

Removal of permanganate reducing compounds and alkyl iodides from a

A method is provided to improve the quality of recycle of certain residues by modifying the separation of alkanes and alkane-like materials and carbonyl-containing impurities from the recycle during the manufacture of acetic acid by the carbonylation of methanol. The improvement comprises operating a prior art stripper column in a reflux manner and partitioning the residue therefrom by the addition of water. The method also reduces the volume of disposal of potentially valuable recyclable reactants.

Removal of carbonyl impurities from a carbonylation process stream

Growing community of inventors

Houston, TX, United States of America

Wayne David Picard