Processes for producing acetic acid
AssigneeCelanese International Corporation
InventorsRonald D. Shaver, Yaw-Hwa Liu, Mark O. Scates
Life of this patent
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Abstract
Process for producing acetic acid are disclosed in which a vapor sidedraw is withdrawn from the second column in the primary purification train. The vapor sidedraw comprises acetic acid and lithium-containing compounds at a concentration of no more than 100 wppb. A bottoms stream that is enriched in lithium-containing compounds, such as lithium acetate, or lithium acetate dihydrate, is also withdrawn from the second column. Advantageously, the vapor sidedraw, or a condensed portion thereof, is directly fed to a metal-exchanged ion exchange resin having acid cation exchange sites to produce purified acetic acid. This prevents displacement of the metals in the ion exchange resin.
Claims20
A process for producing acetic acid comprising:
- carbonylating at least one member selected from the group consisting of methanol, dimethyl ether, and methyl acetate in a reaction medium comprising a rhodium catalyst, water, methyl iodide and lithium-containing compounds;
- separating the reaction medium into a liquid recycle stream and a vapor product stream comprising acetic acid;
- distilling the vapor product stream in a first column to form an overhead and a crude product stream comprising acetic acid;
- distilling the crude product stream in a second column to form a vapor sidedraw comprising acetic acid and lithium-containing compounds at a concentration of no more than 100 wppb, and a bottoms stream enriched in lithium-containing compounds;
- condensing the vapor sidedraw to form a condensed sidedraw;
- and
- feeding the condensed sidedraw to a metal-exchanged ion exchange resin having acid cation exchange sites to produce purified acetic acid.
Dependencies are inferred from the claim text.