Abstract
Abstract Polycarbonate (PC) wastes, including optical discs (CDs) and digital optical discs (DVDs), were chemically recycled into valuable materials such as 4,4′-(propane-2,2-diyl)diphenol (BPA) and etherified derivatives of BPA using sodium hydroxide (NaOH) as the alkali metal catalyst and nanostructured titanium dioxide (nano-TiO2) and microstructured titanium dioxide (micro-TiO2) as the solid supports in the binary green system consisting of water and 2,2′-oxydi(ethan-1-ol) (DEG) under conventional heating method, and data were compared. In this study, the effects of various parameters, such as solvent composition, concentration of NaOH, and solid support, were studied on the reaction progress. In these reactions, the importance of water as the green solvent was investigated in achieving pure BPA as the valuable material. When used with 20% aqueous DEG (pbw), a pure BPA can be obtained at 70% yield in the presence of nano-TiO2 and micro-TiO2 as the solid supports. According to the results, the use of nano-TiO2 in comparison with micro-TiO2 accelerates the chemical recycling of PC wastes. The nano-TiO2 catalyst recovery shows that the recovered solid support is applicable for four cycles. The obtained products were characterized using spectroscopic methods, namely, 1H NMR, 13C NMR, and Fourier transform infrared spectroscopy as well as gas chromatography-mass spectrometry.
Highlights
Polycarbonate (PC) as a useful engineering thermoplastic due to its unique properties is widely used in various applications such as in medical, security compounds, construction materials, data storage, phones, liquid crystal display (LCD) screens, electronic component, bottles, laboratory safety goggles, automotive, aircraft, optical discs (CDs), and digital optical discs (DVDs)
According to the results, when nano-TiO2 as the solid support are used in the reaction mixtures, the chemical recycling of PC wastes is accelerated compared with the experimental conditions using micro-TiO2 as the solid support
The process was carried out in a 50 ml two-necked bottom equipped with a magnetic stirrer, and a reflux condenser and filled with 5.0 g of PC wastes pellets, DEG and water, and nano-TiO2 sodium hydroxide (NaOH) (2% based on total weights of the PC waste and solvent = 0.2 g) as the alkali metal catalyst
Summary
Polycarbonate (PC) as a useful engineering thermoplastic due to its unique properties is widely used in various applications such as in medical, security compounds, construction materials, data storage, phones, liquid crystal display (LCD) screens, electronic component, bottles, laboratory safety goggles, automotive, aircraft, optical discs (CDs), and digital optical discs (DVDs). Our main goal in the current report is the chemical recycling of PC wastes to pure BPA as the valuable material in accordance with the main goals of green chemistry and synthesis using green solvent composition, namely, 2,2′-oxydi(ethan-1-ol) (DEG) and water, in combination with a least amount of alkali metal catalysts in an easy and ecofriendly method in the presence of nano- and micro-TiO2 as an efficient solid support at atmospheric pressure. In these reactions, valuable materials such as BPA and etherified derivatives of BPA were identified. The nano-solid support can be recovered for four cycles and used in the reaction
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
