Production of biofuel precursor chemicals from the mixture of cellulose and polyvinylchloride in polar aprotic solvent

摘要

Polyvinylchloride (PVC) is the major halogen source in municipal solid waste (MSW) and its recycling is problematic. PVC can not only cause various environmental problems by releasing halogens, but also negatively impact other MSW compositions during waste to energy conversion. For instance, co-pyrolysis of biomass with PVC increases solid residue and promotes the formation of CO and CO2 from cellulose. Herein, we report an approach to dehydrochlorinate PVC while simultaneously enhancing the production of valuable chemicals from cellulose. Specifically, cellulose and PVC were co-converted in tetrahydrofuran (THF). It was found that co-conversion of cellulose with PVC significantly increased liquid yield from cellulose and shortened the conversion time compared to converting cellulose alone. Levoglucosan was the major product from cellulose and its highest yield of 40% was achieved with 2.5 wt% of PVC at 335 degrees C after only 8 min of reaction. We have shown that the in-situ generated HCl derived from PVC decomposition serves as acid catalyst to enhance glycosidic bond cleavage in cellulose. Moreover, using a THF/water co-solvent could further enhance the conversion rate and increased liquid yield to a maximum of 92.55%. Pyrolysis of the solid residue did not release chlorinated organics, suggesting that PVC was fully dechlorinated in THF. The present study may be applied to convert PVC-containing, cellulose rich MSW for higher valued products in environmentally friendly approach. (C) 2018 Elsevier Ltd. All rights reserved.