The rapid accumulation of polycarbonate (PC) waste has driven the development of efficient recycling methods. This study presents a comprehensive investigation of solvent-assisted chemical recycling of PC using glycerol, a renewable chemical derived from industrial waste streams. Solvent screening highlighted the critical influence of solvent properties such as dielectric constant, dipole moment and hydrogen-bond accepting ability on depolymerization efficiency. A systematic approach combining Design of Experiments (DoE) and Response Surface Methodology (RSM) was employed to optimize the depolymerization process. Using a Box-Behnken design (BBD), the effects of key process parameters, including temperature, reaction time and the glycerol (GLY:PC) and dimethylformamide (DMF:PC) weight ratios, were evaluated in terms of PC conversion and bisphenol A (BPA) yield. The optimization model predicted that a reaction temperature of 171 degrees C, a reaction time of 1 h and a PC: GLY:DMF ratio of 1:5.05:7.22 would yield 100 % PC conversion and 85 % BPA yield. Experimental validation under these conditions achieved 100 % PC conversion and 83 % BPA yield, confirming the reliability of the model. Product characterization using NMR, LC-HRMS and FTIR confirmed the purity of BPA and provided insights into the reaction mechanism. The solvent recyclability across successive reaction cycles demonstrated the environmental and economic viability of the process. Overall, the energy demand calculation based on the environmental energy impact factor (xi) highlights the industrial relevance of this work and demonstrate an efficient and environmentally friendly catalyst-free route for depolymerization of polycarbonate with strong potential for industrial implementation.

Foreign