Phenanthrenequinone-Based\nHyper-Cross-Linked Polymers\nvia a Waste-Minimizing Friedel–Crafts Alkylation

Although hyper-cross-linked polymers (HCPs) offer significant advantages, their industrial scalability\nhas been impeded by concerns regarding waste generation. To mitigate\nthis challenge, we have successfully developed an efficient and cost-effective\ngreen synthesis method for phenanthrenequinone-based HCPs (PQ-HCPs).\nThis method employs a Friedel–Crafts alkylation reaction, utilizing\ntrifluoromethanesulfonic acid as a catalyst and PQ as the starting\nmaterial. Under low catalyst concentrations, electrophilic sulfonation\nreactions are predominant. However, increasing the catalyst to a 2\nequiv amount significantly shifts the reaction pathway toward Friedel–Crafts\nalkylation cross-linking. The resultant optimal sample, PQ-HCP-1:3,\nboasts an impressive specific surface area of up to 428 m<sup>2</sup>·g<sup>–1</sup>. Dye adsorption experiments on these\nsamples demonstrated a marked selective affinity for Rhodamine B,\nwith the hydrophilicity of the samples being a pivotal factor in the\nadsorption process. This innovative approach substantially outperforms\ntraditional methods, which typically involve ferric chloride (FeCl<sub>3</sub>) and aluminum chloride (AlCl<sub>3</sub>), by significantly\nreducing the production of solid waste and effluent during the chemical\nreaction process.