Hydrocracking is an insufficiently explored route for chemical recycling of plastics waste. Platinum tungstated zirconia (Pt-WZr) was used in a batch reactor at low temperatures of 250 °C and 30 bar H2 pressure for 1-24 h reaction times using low-density polyethylene (LDPE, Mw~76 kDa). We find Pt-WZr is a bifunctional catalyst for LDPE hydrocracking leading to higher value branched fuel- and lubricant-ranged alkanes. Here we demonstrate that the catalyst metal-to-acid site molar ratio (MAB) shifts the product distribution to larger cracked products and increases the isomerization degree in the residual polymer. We propose a new adhesive isomerization mechanism between the metal and Brønsted acid sites in parallel with slow polymer chain cracking, caused by competitive adsorption of the polymer over the liquid products and stereochemical hindrance of methines. This study provides a blueprint on how to engineer effective catalysts for hydrocracking polyolefin plastic wastes using the MAB as a catalyst descriptor.
Vance, Brandon C., et al. "Single pot catalyst strategy to branched products via adhesive isomerization and hydrocracking of polyethylene over platinum tungstated zirconia." Applied Catalysis. B, Environmental, vol. 299, no. C, Jun. 2021. https://doi.org/10.1016/j.apcatb.2021.120483
Vance, Brandon C., Kots, Pavel A., Wang, Cong, Hinton, Zachary R., Quinn, Caitlin M., Epps III, Thomas H., Korley, LaShanda T.J., & Vlachos, Dionisios G. (2021). Single pot catalyst strategy to branched products via adhesive isomerization and hydrocracking of polyethylene over platinum tungstated zirconia. Applied Catalysis. B, Environmental, 299(C). https://doi.org/10.1016/j.apcatb.2021.120483
Vance, Brandon C., Kots, Pavel A., Wang, Cong, et al., "Single pot catalyst strategy to branched products via adhesive isomerization and hydrocracking of polyethylene over platinum tungstated zirconia," Applied Catalysis. B, Environmental 299, no. C (2021), https://doi.org/10.1016/j.apcatb.2021.120483
@article{osti_1976833,
author = {Vance, Brandon C. and Kots, Pavel A. and Wang, Cong and Hinton, Zachary R. and Quinn, Caitlin M. and Epps III, Thomas H. and Korley, LaShanda T.J. and Vlachos, Dionisios G.},
title = {Single pot catalyst strategy to branched products via adhesive isomerization and hydrocracking of polyethylene over platinum tungstated zirconia},
annote = {Hydrocracking is an insufficiently explored route for chemical recycling of plastics waste. Platinum tungstated zirconia (Pt-WZr) was used in a batch reactor at low temperatures of 250 °C and 30 bar H2 pressure for 1-24 h reaction times using low-density polyethylene (LDPE, Mw~76 kDa). We find Pt-WZr is a bifunctional catalyst for LDPE hydrocracking leading to higher value branched fuel- and lubricant-ranged alkanes. Here we demonstrate that the catalyst metal-to-acid site molar ratio (MAB) shifts the product distribution to larger cracked products and increases the isomerization degree in the residual polymer. We propose a new adhesive isomerization mechanism between the metal and Brønsted acid sites in parallel with slow polymer chain cracking, caused by competitive adsorption of the polymer over the liquid products and stereochemical hindrance of methines. This study provides a blueprint on how to engineer effective catalysts for hydrocracking polyolefin plastic wastes using the MAB as a catalyst descriptor.},
doi = {10.1016/j.apcatb.2021.120483},
url = {https://www.osti.gov/biblio/1976833},
journal = {Applied Catalysis. B, Environmental},
issn = {ISSN 0926-3373},
number = {C},
volume = {299},
place = {United States},
publisher = {Elsevier},
year = {2021},
month = {06}}
University of Delaware, Newark, DE (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES); National Science Foundation (NSF); National Institute of General Medical Sciences (NIGMS); National Institutes of Health (NIH)