Polymeric aluminum porphyrin: Controllable synthesis of ultra-low molecular weight CO2-based polyols

• Published in: Chinese chemical letters 2023-08, Vol.34 (8), p.108011-438, Article 108011
• Main Authors: Zhuo, Chunwei, Cao, Han, Wang, Xiaoshen, Liu, Shunjie, Wang, Xianhong
• Format: Article
• Language: English
• Subjects: Aluminum porphyrin; CO2-polyols; Polymeric catalyst; Proton tolerance; Ultra-low molecular weight
• ISSN: 1001-8417; 1878-5964
• DOI: 10.1016/j.cclet.2022.108011

Carbon dioxide-based polyols with ultra-low molecular weight (ULMW, Mn < 1000 g/mol) are emergent polyurethane precursors with economic and environmental benefits. However, the lack of effective proton-tolerant catalytic systems limits the development of this field. In this work, the polymeric aluminum porphyrin catalyst (PAPC) system was applied to the copolymerization of CO2 and propylene oxide, where sebacic acid, bisphenol A, poly(ethylene glycol), and water were used as chain transfer agents to achieve the controlled synthesis of CO2-polyols. The molecular weight of the resulting CO2-polyols could be facilely regulated in the range of 400–930 g/mol at low catalyst loadings, fully demonstrating its catalytic advantages of high activity, high product selectivity, and excellent proton tolerance of PAPC. Meanwhile, the catalytic efficiency of PAPC could reach up to 2.1–5.2 kg/g under organic CTA conditions, even reaching 1.9 kg/g using water as the CTA. The cPC content could be controlled within 1.0 wt% under the optimized conditions, indicating the excellent controllability of the PAPC system. ULMW CO2-polyols combines the advantages of low viscosity (∼3000 mPa s at 25 °C), low glass transition temperature (∼−73 °C), and high carbonate unit content (∼40%), which is important for the development of high-performance polyurethanes. Herein, we demonstrated a polymeric aluminum porphyrin catalyst (PAPC) with the multi-center cooperative effect. PAPC showed excellent tolerance of chain transfer agents and realized the controllable synthesis of CO2-polyols with ultra-low molecular weight (Mn < 1000 g/mol). [Display omitted]