基础化工行业周报：PTA板块涨幅明显，硫磺、顺酐等价格上涨

Investment Rating - Industry investment rating: Overweight [1] Core Views - The chemical sector's overall performance ranked 19th with a fluctuation of 1.59% during the week of March 8-14, 2025, outperforming the Shanghai Composite Index by 0.19 percentage points and the ChiNext Index by 0.61 percentage points [3][26] - The chemical industry is expected to continue its trend of divergence in 2025, with recommendations to focus on synthetic biology, pesticides, chromatography media, sweeteners, vitamins, light hydrocarbon chemicals, COC polymers, and MDI [4] Summary by Sections Industry Review - The chemical sector's overall fluctuation was 1.59%, ranking 19th among sectors [3][26] - The top three performing sub-sectors were nitrogen fertilizers (5.16%), oil and gas refining (4.63%), and synthetic resins (4.55%) [27] Supply-Side Tracking - A total of 136 companies in the chemical industry had their production capacities affected, with 7 new maintenance cases and 3 restarts reported [15] Key Industry Dynamics - The implementation of quota policies for third-generation refrigerants is expected to lead to a high prosperity cycle, with demand remaining stable due to market expansion in Southeast Asia [5] - The electronic specialty gases market is characterized by high technical barriers and high added value, presenting significant domestic substitution opportunities [6] - The light hydrocarbon chemical trend is becoming global, with a shift towards lighter raw materials for olefin production [8] - The COC polymer industry is accelerating its domestic industrialization process, with significant breakthroughs expected [9] - Potash fertilizer prices are anticipated to rebound as major suppliers reduce production and inventory pressures ease [10] - The MDI market is expected to improve due to oligopolistic supply dynamics and stable demand growth [13]