This invention relates to a method of continuously preparing acrylic acid and an apparatus using the same, the method including: (1) subjecting a feed including propane, oxygen, water vapor and carbon dioxide to partial oxidation using a catalyst, thus obtaining an acrylic acid-containing mixed gas, (2) separating the acrylic acid-containing mixed gas into an acrylic acid-containing solution and a gas byproduct, (3) separating an acrylic acid solution from the separated acrylic acid-containing solution, and (4) recycling the separated gas byproduct into the feed.

This invention relates to a method of continuously preparing acrylic acid and an apparatus using the same, the method including: (1) subjecting a feed including propane, oxygen, water vapor and carbon dioxide to partial oxidation using a catalyst, thus obtaining an acrylic acid-containing mixed gas, (2) separating the acrylic acid-containing mixed gas into an acrylic acid-containing solution and a gas byproduct, (3) separating an acrylic acid solution from the separated acrylic acid-containing solution, and (4) recycling the separated gas byproduct into the feed.

This invention relates to a method of continuously preparing acrylic acid and an apparatus using the same, the method including: (1) subjecting a feed including propane, oxygen, water vapor and carbon dioxide to partial oxidation using a catalyst, thus obtaining an acrylic acid-containing mixed gas, (2) separating the acrylic acid-containing mixed gas into an acrylic acid-containing solution and a gas byproduct, (3) separating an acrylic acid solution from the separated acrylic acid-containing solution, and (4) recycling the separated gas byproduct into the feed.

Disclosed is a method for linkage recovery of an organic acid in an aqueous organic acid solution. The method comprises: mixing a solution with an organic acid concentration lower than 20 wt % with a specific extractant and then subjecting same to counter-current extraction so as to obtain an extract phase and a raffinate phase; and subjecting the extract phase together with a solution with an acid concentration higher than 70 wt % to an azeotropic rectification so as to recover an organic acid. When the concentration of the aqueous organic acid solution is 20 wt %-70 wt %, the aqueous organic acid solution is extracted and concentrated to make the concentration of the aqueous organic acid solution higher than 70 wt %.

The invention relates to the production of (meth)acrylic acid, and to implementation of a step of condensing water contained in a recycled gas effluent and/or in the air feed in a (meth)acrylic acid production process, which further includes a process for purifying a reaction mixture comprising (meth)acrylic acid without using azeotropic solvent and based on the use of two distillation columns.

The invention relates to the production of (meth)acrylic acid, and to implementation of a step of condensing water contained in a recycled gas effluent and/or in the air feed in a (meth)acrylic acid production process, which further includes a process for purifying a reaction mixture comprising (meth)acrylic acid without using azeotropic solvent and based on the use of two distillation columns.

The invention relates to the production of (meth)acrylic acid, and to implementation of a step of condensing water contained in a recycled gas effluent and/or in the air feed in a (meth)acrylic acid production process, which further includes a process for purifying a reaction mixture comprising (meth)acrylic acid without using azeotropic solvent and based on the use of two distillation columns.

A process for producing acetic acid including an acetic acid collection step for feeding a first distillation column with a volatile component at least containing acetic acid, methyl acetate, methyl iodide, water, and hydrogen iodide. Separating a first lower boiling point component as an overhead, and collecting a first liquid stream containing acetic acid. An acetic acid purification step for feeding a second distillation column with the first liquid stream, and separating a second lower boiling point component as an overhead. Collecting a second liquid stream containing acetic acid. An alkali component is added or mixed for distilling a mixture to be treated containing the first liquid stream and the alkali component in the second distillation column. In the mixture, at least one component (A) having a boiling point lower than acetic acid. The at least one component (A) having a concentration of 0.1 to 15% by weight.

A process for producing acetic acid including an acetic acid collection step for feeding a first distillation column with a volatile component at least containing acetic acid, methyl acetate, methyl iodide, water, and hydrogen iodide. Separating a first lower boiling point component as an overhead, and collecting a first liquid stream containing acetic acid. An acetic acid purification step for feeding a second distillation column with the first liquid stream, and separating a second lower boiling point component as an overhead. Collecting a second liquid stream containing acetic acid. An alkali component is added or mixed for distilling a mixture to be treated containing the first liquid stream and the alkali component in the second distillation column. In the mixture, at least one component (A) having a boiling point lower than acetic acid. The at least one component (A) having a concentration of 0.1 to 15% by weight.

A process for producing acetic acid including an acetic acid collection step for feeding a first distillation column with a volatile component at least containing acetic acid, methyl acetate, methyl iodide, water, and hydrogen iodide. Separating a first lower boiling point component as an overhead, and collecting a first liquid stream containing acetic acid. An acetic acid purification step for feeding a second distillation column with the first liquid stream, and separating a second lower boiling point component as an overhead. Collecting a second liquid stream containing acetic acid. An alkali component is added or mixed for distilling a mixture to be treated containing the first liquid stream and the alkali component in the second distillation column. In the mixture, at least one component (A) having a boiling point lower than acetic acid. The at least one component (A) having a concentration of 0.1 to 15% by weight.