On February 10, the phthalic anhydride market in Shandong exhibited a weak consolidation trend. The mainstream negotiated prices for ortho-xylene-based phthalic anhydride were in the range of 6,000–6,200 yuan/ton, while naphthalene-based phthalic anhydride was quoted at 5,550–5,900 yuan/ton. The price of raw material ortho-xylene remained stable, whereas industrial naphthalene prices experienced a fluctuating decline, leading to a reduction in phthalic anhydride production costs. Downstream plasticizer prices also fluctuated downward. Phthalic anhydride production facilities maintained stable operations, with plant operating rates remaining low and steady. Market supply of phthalic anhydride remained tight. Plasticizer enterprises maintained stable operating loads, but rigid demand support for phthalic anhydride weakened. The outlook for the phthalic anhydride market suggests continued weak consolidation.