According to the present invention, there is provided a process for
inhibiting the polymerization of an aromatic vinyl compound which is
capable of efficiently inhibiting the polymerization of an aromatic vinyl
compound not only in an initial stage but also over a long term in the
stage of producing, purifying, storing or transporting the aromatic vinyl
compound, and which is excellent in handling. The present invention
relates to a process for inhibiting the polymerization of an aromatic
vinyl compound which requires the step of adding a 2-nitrophenol compound
in combination with a sulfonic acid compound to the aromatic vinyl
monomer during the stage of producing, purifying, storing or transporting
the aromatic vinyl compound.