Affiliation:
1. Department of Chemical Technology of Basic Organic and Petrochemical Synthesis, Mendeleev University of Chemical Technology, 125047 Moscow, Russia
2. JSC “PMP”, 199004 Saint-Petersburg, Russia
3. Voronezhsintezkauchuk JSC, 394014 Voronezh, Russia
Abstract
This work is concerned with polyethylene terephthalate (PET) saponification by different potassium compounds in various polyols as well as biodiesel’s main by-product, crude glycerol. It was established that reaction conditions (initial PET/K+ molar ratio, reaction time, etc.) could control the molecular weight of obtained oligomeric products. In ethylene glycol, depolymerization proceeds rapidly, and already at 10–30 min, PET is completely dissolved in the reaction mixture with the formation of liquid oligomers. Then, these oligomers react with potassium compounds, and after 200 min of the process, there are only solid, low-molecular-weight products (dipotassium terephthalate, monomers, and dimers). At the same time, PET saponification in pure glycerol is less effective, and solid polyether flakes could not fully decompose even after 200 min of the process. Crude glycerol takes the middle position between pure polyols. Based on the obtained data, an improved kinetic model was developed, and rate constants were estimated. This model takes into account PET saponification by potassium salts as well as direct PET glycolysis. Ethylene glycol is formed in situ by transesterification between fatty acid ethylene glycol esters and glycerol in the case of pure and crude glycerol.
Reference22 articles.
1. A review of microplastics pollution in the soil and terrestrial ecosystems: A global and Bangladesh perspective;Sarker;Sci. Total Environ.,2020
2. Microplastic pollution in drinking water;Kirstein;Curr. Opin. Toxicol.,2021
3. James, A., Rahman, M.R., Khusairy Bin Bakri, M., and Mahbubul Matin, M. (2022). Recycled Plastic Biocomposites, Elsevier.
4. Rahman, M.R., Khusairy Bin Bakri, M., Mahbubul Matin, M., and Law Nyuk Khui, P. (2022). Recycled Plastic Biocomposites, Woodhead Publishing.
5. Design and Characterization of a New Food Packaging Material by Recycling Blends Virgin and Recovered polyethylene terephthalate;Masmoudi;Polym. Eng. Sci.,2020