Provided is a method for producing acrylic acid, the method including: preparing a reaction product containing acrylic acid by supplying lactic acid to a reactor and performing a dehydration reaction; supplying a reactor discharge stream containing the reaction product to a cooling tower and condensing the result to transfer a lower discharge stream including a condensate to an acrylic acid purification unit and supplying a non-condensate discharged as an upper discharge stream to a distillation tower; and, in the distillation tower, circulating the lower discharge stream containing acrylic acid to the cooling tower, and removing acetaldehyde from the upper discharge stream.

Provided is a method for producing acrylic acid, the method including: preparing a reaction product containing acrylic acid by supplying lactic acid to a reactor and performing a dehydration reaction; supplying a reactor discharge stream containing the reaction product to a cooling tower and condensing the result to transfer a lower discharge stream including a condensate to an acrylic acid purification unit and supplying a non-condensate discharged as an upper discharge stream to a distillation tower; and, in the distillation tower, circulating the lower discharge stream containing acrylic acid to the cooling tower, and removing acetaldehyde from the upper discharge stream.

The object of an aspect of the present invention is to provide a method for producing a long-chain fatty acid, the method making it possible to prevent a coloring component from being contained in the long-chain fatty acid and recover the long-chain fatty acid at a high yield. The above problem is solved by providing a method for producing a long-chain fatty acid, the method including the steps of: (a) with use of an enzyme, decomposing, into fatty acids, triglyceride contained in a raw vegetable oil which is derived from a vegetable-derived oil-containing waste; (b) removing, by distillation, a short-chain fatty acid contained in the raw vegetable oil which has been subjected to the step (a); and (c) recovering, by short-path distillation, a long-chain fatty acid contained in the raw vegetable oil which has been subjected to the step (b).

The object of an aspect of the present invention is to provide a method for producing a long-chain fatty acid, the method making it possible to prevent a coloring component from being contained in the long-chain fatty acid and recover the long-chain fatty acid at a high yield. The above problem is solved by providing a method for producing a long-chain fatty acid, the method including the steps of: (a) with use of an enzyme, decomposing, into fatty acids, triglyceride contained in a raw vegetable oil which is derived from a vegetable-derived oil-containing waste; (b) removing, by distillation, a short-chain fatty acid contained in the raw vegetable oil which has been subjected to the step (a); and (c) recovering, by short-path distillation, a long-chain fatty acid contained in the raw vegetable oil which has been subjected to the step (b).

Acetic acid is manufactured by a method of carbonylating raw material with carbon monoxide, the method comprising: a reaction step of forming a reaction mixture containing acetic acid inside a reactor; and a purification step of purifying the reaction mixture to thereby obtain product acetic acid. The purification step includes: a flash evaporation step of separating the reaction mixture into a vapor-phase mixture and a liquid-phase mixture; a first distillation step of distilling the vapor-phase mixture to thereby separate and remove low-boiling point components and obtain crude acetic acid; and a second distillation step of introducing the crude acetic acid into a heavy ends column and distilling the crude acetic acid to thereby purify the crude acetic acid and obtain product acetic acid. In the second distillation step, the low-boiling point components remaining in the crude acetic acid are drawn out from a column top of the heavy ends column.

Acetic acid is manufactured by a method of carbonylating raw material with carbon monoxide, the method comprising: a reaction step of forming a reaction mixture containing acetic acid inside a reactor; and a purification step of purifying the reaction mixture to thereby obtain product acetic acid. The purification step includes: a flash evaporation step of separating the reaction mixture into a vapor-phase mixture and a liquid-phase mixture; a first distillation step of distilling the vapor-phase mixture to thereby separate and remove low-boiling point components and obtain crude acetic acid; and a second distillation step of introducing the crude acetic acid into a heavy ends column and distilling the crude acetic acid to thereby purify the crude acetic acid and obtain product acetic acid. In the second distillation step, the low-boiling point components remaining in the crude acetic acid are drawn out from a column top of the heavy ends column.

Acetic acid is manufactured by a method of carbonylating raw material with carbon monoxide, the method comprising: a reaction step of forming a reaction mixture containing acetic acid inside a reactor; and a purification step of purifying the reaction mixture to thereby obtain product acetic acid. The purification step includes: a flash evaporation step of separating the reaction mixture into a vapor-phase mixture and a liquid-phase mixture; a first distillation step of distilling the vapor-phase mixture to thereby separate and remove low-boiling point components and obtain crude acetic acid; and a second distillation step of introducing the crude acetic acid into a heavy ends column and distilling the crude acetic acid to thereby purify the crude acetic acid and obtain product acetic acid. In the second distillation step, the low-boiling point components remaining in the crude acetic acid are drawn out from a column top of the heavy ends column.

Provided is a process for producing acrylic acid, the process including supplying a lactic acid raw material to an upper portion of a distillation tower; supplying water to a lower portion of the distillation tower; supplying a first lactic acid vapor vaporized in the distillation tower to a reactor; and supplying a second aqueous lactic acid solution not vaporized in the distillation tower to a middle portion of the distillation tower. The process uses a distillation tower instead of a vaporizer, and is capable of preventing formation of a lactic acid oligomer during vaporization of an aqueous lactic acid solution, and, by introducing a concentrated lactic acid raw material to the distillation tower as it is, is capable of producing acrylic acid without a separate dilution device.

Provided is a process for producing acrylic acid, the process including supplying a lactic acid raw material to an upper portion of a distillation tower; supplying water to a lower portion of the distillation tower; supplying a first lactic acid vapor vaporized in the distillation tower to a reactor; and supplying a second aqueous lactic acid solution not vaporized in the distillation tower to a middle portion of the distillation tower. The process uses a distillation tower instead of a vaporizer, and is capable of preventing formation of a lactic acid oligomer during vaporization of an aqueous lactic acid solution, and, by introducing a concentrated lactic acid raw material to the distillation tower as it is, is capable of producing acrylic acid without a separate dilution device.

Provided is a process for producing acrylic acid, the process including supplying a lactic acid raw material to an upper portion of a distillation tower; supplying water to a lower portion of the distillation tower; supplying a first lactic acid vapor vaporized in the distillation tower to a reactor; and supplying a second aqueous lactic acid solution not vaporized in the distillation tower to a middle portion of the distillation tower. The process uses a distillation tower instead of a vaporizer, and is capable of preventing formation of a lactic acid oligomer during vaporization of an aqueous lactic acid solution, and, by introducing a concentrated lactic acid raw material to the distillation tower as it is, is capable of producing acrylic acid without a separate dilution device.