Chemical recycling of polycarbonate in a semi-continuous lab-plant. A green route with methanol and methanol–water mixtures

Green and inexpensive method to recover Bisphenol-A from polycarbonate wastes

“…The chemical recycling of polymer wastes has been gaining great attention as a common root in obtaining valuable products [3] . Depolymerization processes have been reported in order to decompose PC into its monomer, bisphenol A (BPA) [4] , which is the main raw material for polycarbonate (PC) manufacturing. In this report, Pinero´s research group investigated chemical recycling of PC in a semi-continuous lab-plant, using methanol and methanol-water mixtures as degradation reagents.…”

CeO2 nanocatalysts for the chemical recycling of polycarbonate

“…The solid product was dissolved in acetonitrile that was quantitatively analyzed by high performance liquid chromatography (HPLC) that is equipped with two detectors, a UV (254 nm, L-2400, Hitachi) and a differential refractive index (L-2490, Hitachi) detectors connected in series using a column (RSpak DE-413, 4.6 mm ID × 15 cm length, Shodex) coated with a polymethacrylate gel by flowing a mixed elution solvent of water-acetonitrile (55:45 (v/v)) at a volumetric flow rate of 0.5 mL/min and 40°C [21]. The yields of monomer bisphenol A (BPA) and phenol were determined using the calibration curves created from the reference BPA and phenol samples purchase from Wako chemicals and using the following equation [20]:…”

“…Moreover, homogeneous catalytic reagents have been used to accelerate the reaction at low temperatures [14][15][16][17]. Regarding the chemical recycling of PC materials, the materials were depolymerized via hydrolysis in the presence of Na 2 CO 3 [18], NaOH [19], and manganese acetate [20] as catalytic reagents, via alcoholysis [21,22], and via glycolysis [23]. The chemical recycling of PC materials was also performed using high pressure and high temperature steam [24] or fluidized bed reactor via thermal pyrolysis [25] and via steam hydrolysis [26].…”

Poly(bisphenol A carbonate) Recycling: High Pressure Hydrolysis Can Be a Convenient Way

“…They are based, for instance, on the use of solvent systems (Pan et al, 2006;Piñero et al, 2005) such as methylene chloride with ammonia, phenol in combination with an alkali catalyst, or via trans-esterification (alcoholysis) in super-or sub-critical conditions. These processes can require a complicate product separation in addition with environmental safety problems related to the use of more or less toxic organic solvents.…”

“…They found that by using more than a stoichiometric amount of methanol, DMC was produced in quantitative yields, highlighting the importance of adopting also an optimized ratio between PC and methanol. Piñero et al (2005) used methanol-water mixtures and developed (Piñero et al, 2006) a shrinking particle model to describe the reactive dissolution of the BPA-PC particles in semicontinuous de-polymerization of polycarbonate. Jie et al (2006) studied decomposition in ethanol that has a critical point practically at same temperature and a lower pressure than that of methanol, allowing lower operating temperatures and pressures.…”