Method for producing (meth)acrylic acid
AssigneeNippon Shokubai Co., Ltd.
InventorsKazuhiko Sakamoto, Kazuo Ohkouchi, Tomohiro Nakae
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Abstract
An object of this invention is to provide a method for producing acrylic acid that enables to suppress adverse influence of byproducts during distillation and to accomplish long-term continuous operation of the acrylic acid production apparatus. This invention is directed to a method for producing (meth)acrylic acid comprising the step of isolating (meth)acrylic acid from a liquid containing (meth)acrylic acid by distillation wherein the liquid contains glyoxal (including its hydrate) in a concentration of 0.1 mass % or less.
Claims6
A method for producing (meth)acrylic acid comprising the steps of obtaining a mixed gas containing (meth)acrylic acid and glyoxal by catalytic gas phase oxidation using propylene and/or acrolein, or using at least one compound selected from the group consisting of isobutylene, t-butyl alcohol, and methacrolein,
- contacting the mixed gas with a collecting liquid to obtain a (meth)acrylic acid aqueous solution,
- separating the (meth)acrylic acid aqueous solution into (meth)acrylic acid and a discharged liquid containing glyoxal by distillation,
- separating a part or all of the discharged liquid into a permeated liquid and an impermeated liquid containing glyoxal with the use of reverse osmosis membrane, thereby reducing a concentration of glyoxal contained in the permeated liquid, and
- recycling a part or all of the permeated liquid by circulation as the collecting liquid.
Dependencies are inferred from the claim text.