Process for producing acetic acid
AssigneeDaicel Corporation
InventorsMasahiko SHIMIZU, Hiroyuki MIURA, Yoshihisa MIZUTANI
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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in which PRC's and methyl iodide are concentrated, and an extraction mixture falling from the concentration zone is withdrawn as the side-cut stream (5B).
Claims15
A process for separating or removing a permanganate reducing compound (PRC) from a mixed composition containing at least PRC and methyl iodide, the process comprising distilling the mixed composition in a 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 a concentration zone of a PRC and methyl iodide in a distillation column of the distillation step, and
- withdrawing an extraction mixture falling from the concentration zone as the side-cut stream.
A process for producing acetic acid, comprising the steps of:
- distilling a mixed composition containing at least a pemianganate 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.
Dependencies are inferred from the claim text.