Process for producing acetic acid
AssigneeDaicel Corporation
InventorsMasahiko Shimizu, Hiroyuki Miura, Yoshihisa Mizutani
Life of this patent
Estimating the term…
Abstract
A process for producing acetic acid while efficiently separating permanganate reducing compounds (PRC's) and methyl iodide is provided. PRC's are separated or removed from a mixed composition (3A) containing PRC's and methyl iodide by distilling the mixed composition in a distillation step (5) to form an overhead stream (5A), a side-cut stream (5B), and a lower stream (5C). In a distillation column of the distillation step (5), an extractant (e.g., water) extracting PRC's preferentially to methyl iodide is added to a concentration zone in which PRC's and methyl iodide are concentrated, and an extraction mixture falling from the concentration zone is withdrawn as the side-cut stream (5B).
Claims14
A process for producing acetic acid, comprising the steps of:
- distilling a mixed composition containing at least a permanganate reducing compound (PRC), methyl iodide, methyl acetate, and acetic acid to separate the mixed composition into an overhead and an acetic acid stream, the overhead containing at least a PRC and methyl iodide, and the acetic acid stream containing product acetic acid, and
- subjecting at least a portion of the overhead to a second distillation step to form an overhead stream, a side-cut stream, and a lower stream;
- wherein the process further comprises the steps of:
- adding an extractant extracting a PRC preferentially to methyl iodide to the concentration zone of a PRC and methyl iodide in the distillation column of the second distillation step, and
- withdrawing an extraction mixture falling from the concentration zone as the side-cut stream to biphasically separate the extraction mixture into an upper aqueous phase and a lower organic phase.
Dependencies are inferred from the claim text.