Recently, the domestic phthalic anhydride market has plummeted. Especially in the middle and late months of the month, the market decline accelerated, with a sharp drop of 1,200 yuan/ton compared to the beginning of the month. To explore why the market has adjusted so fiercely, we have to look back at the market in April. In April, the domestic phthalic anhydride market experienced a strong unilateral rise, recording the largest increase in a single month in recent years, with a monthly increase of 25%, and an increase of 41.67% from the low at the beginning of the year. In the short term, after the sharp decline of Sinopec's phthalic anhydride and the approaching of the end of the month, it is expected that the domestic phthalic anhydride market will be weak and volatile before the end of the month. However, in the medium to long term, the phthalic anhydride market outlook is still not optimistic and may continue to test the previous lows.