Fractional separation of (meth)acrylic acid from mixture

PROBLEM TO BE SOLVED: To provide a method for fractional separation of (meth)acrylic acid from a mixture containing (meth)acrylic acid reducing formation of deposition in a rectifying column (especially the surface of an evaporator). SOLUTION: In a method for fractionally separating (meth)acrylic acid from a mixture containing (meth)acrylic acid taking out the (meth)acrylic acid from a rectifying column at an upper position in a level into which a liquid mixture containing (meth)acrylic acid enters the rectifying column, a reflux liquid descending in the rectifying column is taken out from the column at least one point of the column and (meth)acrylic acid of an oligomer and/or a polymer existing in the column is separated, and the (meth)acrylic acid is fractionally separated from the mixture containing (meth)acrylic acid recycling the reflux liquid to the rectifying column. COPYRIGHT: (C)1996,JPO