Patent ID: 7244863

Claim:
A process for producing acrylic acid or methacrylic acid or an ester of any of these (hereinafter referred to as “(meth)acrylic acid compound”) which is a process for producing and/or purifying a (meth)acrylic acid compound, characterized in that mixtures of high-boiling heavy ingredients (hereinafter referred to as “high-boiling matter mixtures”) discharged from individual step units are classified by the content therein of acrylic acid or methacrylic acid (hereinafter referred to as “(meth)acrylic acid”) and/or of the dimer thereof and handled, wherein the high-boiling matters are classified into a hydrophilic high-boiling matter in which the total content of (meth)acrylic acid and its dimer is 10% by weight or higher and a hydrophobic high-boiling matter in which the total content of the same is lower than 10% by weight, and handled.