In the purification and distillation step of acrylic acid (including (meth)acrylic
acid), stable continuous operation for a long period is enabled by inhibiting the
undesirable polymerization reaction of acrylic acid thereby to prevent the device
from a trouble such as clogging. A process for producing acrylic acid which comprises
purifying crude acrylic acid prepared by vapor-phase catalytic oxidation by distillation,
wherein the concentration of -acryloxypropionic acid in the feed stream
to a distillation column mainly for the separation of water from acrylic acid is
controlled to be at most one-fiftieth of the concentration of acrylic acid; the
concentration of -acryloxypropionic acid in the feed stream to a distillation
column mainly for the separation of acetic acid from acrylic acid is controlled
to be at most one-fortieth of the concentration of acrylic acid; and the concentration
of -acryloxypropionic acid in the feed stream to a distillation column mainly
for the separation of acrylic acid from water, acetic acid and a solvent is controlled
to be at most one-fiftieth of the concentration of acrylic acid.