2024 AIChE Annual Meeting
(385g) Sulfuric Acid for Chemical Recycling of Polycarbonate in Water
Author
Abedsoltan, H. - Presenter, University of Toledo
This study is centered on the chemical recycling of poly (bisphenol-A carbonate) (PC) pellets through hydrolysis, where concentrated sulfuric acid is utilized as a catalyst in a water medium. The impact of varying sulfuric acid concentrations and reaction temperatures on the hydrolysis rate of PC was investigated. Experiments were conducted to observe the conversion rate of PC over time with sulfuric acid concentrations ranging from 10M to 16M and temperatures between 110°C and 150°C. The kinetics of the PC hydrolysis process were modeled using a pseudo-first-order reaction framework, through which specific reaction rate constants were determined. The overall activation energy for the hydrolysis of PC was calculated using the Arrhenius equation. The recovery of the catalyst (sulfuric acid) post-hydrolysis through distillation, its characterization via titration, and its reapplication in subsequent hydrolysis experiments to assess catalyst reusability were also explored. It was found that sulfuric acid can be maintained in its acidic state and is effective as a catalyst for up to five cycles of reuse. The reduction in the size of the PC due to hydrolysis was examined as well. Moreover, a mechanism for the hydrolysis of polycarbonate in the presence of an aqueous solution of sulfuric acid was proposed.