Chemical recycling of polycarbonate wastes into bisphenol A by using green solvent composition

Performance of Fe3O4@SiO2 as the recyclable heterogeneous catalyst in the bisphenol A recovery from polycarbonate wastes

“…Due to increased polycarbonate (PC) production and therefore to recycle the end used PC wastes, demands for finding some adequate and environmentally benign methods for recycling these polymeric wastes have increased dramatically, and as a result, researchers are conducting experiments to find economical, green, and simple methods for chemical recycling. 1 In recent years, several methods have been presented for chemical recycling of PC wastes involving hydroglycolysis, 2,3 hydrolysis, 4,5 glycolysis, 6 -8 methanolysis in ionic liquids, 9 pyrolysis, 10 alcoholysis in supercritical conditions, 11 and aminolysis, 12 all of which have their own merits and drawbacks. Homogeneous catalysts such as sodium hydroxide (NaOH) have higher catalytic activity than heterogeneous catalysts because of its solubility in the reaction media, which increases catalytic site accessibility for the substrate, but recycling and reusing of this catalyst is difficult, costly, and often time-consuming.…”

Recyclable Nanomagnetic Fe3O4@APTES catalyst role on the Hydrolysis of Polycarbonate Wastes

“…In another particular case, Jafarzadeh's research group has used magnetically recoverable trifluoroacetic acid-immobilized Fe3O4@SiO2-APTES core-shell nanocatalyst for the Friedländer synthesis of quinolines under solvent-free condition [31]. Our research group has carried out in the past extensive studies on the chemical recycling of PC wastes to recover BPA as the valuable materials in the presence of sodium hydroxide (NaOH) as the homogeneous catalyst, water [32] and glycerin/water [33], and sorbitol/glycerin/water [34] under hydrothermal conditions and ethylene glycol (EG) [35] and glycerin/water [36] under microwave irradiation. Recently our research group, depolymerization of PC wastes was carried out to recover bis (4-hydroxybutyl hydrogen carbonate) of BPA (DHB-BPA), mono (4-hydroxybutyl hydrogen carbonate) of BPA (MHB-BPA) and BPA itself in the presence of (1,4-butanediol and water) as the solvent composition, nanoparticles TiO2 (NPs-TiO2) and microparticles TiO2 (MPs-TiO2) as the recyclable solid supports and NaOH as the homogeneous catalyst under simple heating method [37].…”