On February 9, the phthalic anhydride market in Shandong region showed a weak consolidation trend. The mainstream negotiated prices for o-xylene-based phthalic anhydride were between 6,000 and 6,200 yuan per ton, while those for naphthalene-based phthalic anhydride ranged from 5,550 to 5,900 yuan per ton. The price of raw material o-xylene remained stable, while the price of industrial naphthalene fluctuated downward, leading to a decrease in the production cost of phthalic anhydride. Downstream plasticizer prices also experienced a fluctuating decline. Phthalic anhydride production facilities maintained stable operations, with the operating rate of phthalic anhydride enterprises stabilizing at a low level. The supply in the phthalic anhydride market tightened, while the operating load of plasticizer enterprises remained temporarily stable. The support from rigid demand for phthalic anhydride weakened, and the market outlook is expected to continue with a weak consolidation trend.