Comparative Reactivity of Different Polyols in the PET Saponification Process

This work is concerned with polyethylene terephthalate (PET) saponification by different potassium compounds in various polyols as well biodiesel’s main by-product, crude glycerol. It was established that reaction conditions (initial PET/K+ molar ratio, time, etc.) could control the molecular weight of obtained oligomeric products. In ethylene glycol, depolymerization proceeds rapidly, and already at 10–30 min, PET completely dissolved mixture formation liquid oligomers. Then, these oligomers react compounds, after 200 min process, there are only solid, low-molecular-weight products (dipotassium terephthalate, monomers, dimers). At same pure glycerol less effective, solid polyether flakes not fully decompose even process. Crude takes middle position between polyols. Based on data, an improved kinetic model developed, rate constants were estimated. into account salts direct glycolysis. Ethylene glycol formed situ transesterification fatty acid esters case