On January 28, the phthalic anhydride market in Shandong exhibited a volatile consolidation trend. The mainstream negotiated prices for o-xylene-based phthalic anhydride ranged from 6,200 to 6,350 yuan/ton, while naphthalene-based phthalic anhydride was quoted between 5,800 and 6,100 yuan/ton. The prices of raw materials, including o-xylene and industrial naphthalene, remained stable, leading to steady production costs for phthalic anhydride. Downstream plasticizer prices experienced a volatile uptrend. Phthalic anhydride plants maintained stable operations, with their operating rates stabilizing at relatively low levels, contributing to a tight supply in the market. Plasticizer enterprises operated at a steady capacity, sustaining a certain level of rigid demand for phthalic anhydride. Looking ahead, the phthalic anhydride market is expected to continue fluctuating within a narrow range.