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Article

Nitric Acid Functionalization of Petroleum Coke to Access Inherent Sulfur

Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada
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Author to whom correspondence should be addressed.
Catalysts 2020, 10(2), 259; https://doi.org/10.3390/catal10020259
Received: 26 December 2019 / Revised: 17 February 2020 / Accepted: 18 February 2020 / Published: 20 February 2020
(This article belongs to the Special Issue Commemorative Issue in Honor of Professor Hugo de Lasa)
Sulfonated carbon-based catalysts have been identified as promising solid acid catalysts, and petroleum coke (petcoke), a byproduct of the oil industry, is a potential feedstock for these catalysts. In this study, sulfur-containing (6.5 wt%) petcoke was used as a precursor for these catalysts through direct functionalization (i.e., without an activation step) with nitric acid to access the inherent sulfur. Catalysts were also prepared using sulfuric acid and a mixture of nitric and sulfuric acid (1:3 vol ratio). Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and titration were used to identify and quantify the acid sites. The activities of the prepared catalysts were determined for the esterification of octanoic acid with methanol. Petcoke had few −SO3H groups, and correspondingly no catalytic activity for the reaction. All acid treatments increased the number of −SO3H groups and promoted esterification. Treatment with nitric acid alone resulted in the oxidation of the inherent sulfur in petcoke to produce ~0.7 mmol/g of strong acid sites and a total acidity of 5.3 mmol/g. The acidity (strong acid and total) was lower with sulfuric acid treatment but this sample was more active for the esterification reaction (TOF of 31 h−1 compared to 7 h−1 with nitric acid treatment). View Full-Text
Keywords: petroleum coke; functionalization; solid acid catalyst; sulfur; esterification petroleum coke; functionalization; solid acid catalyst; sulfur; esterification
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MDPI and ACS Style

Huang, Q.; Schafranski, A.S.; Hazlett, M.J.; Xiao, Y.; Hill, J.M. Nitric Acid Functionalization of Petroleum Coke to Access Inherent Sulfur. Catalysts 2020, 10, 259. https://doi.org/10.3390/catal10020259

AMA Style

Huang Q, Schafranski AS, Hazlett MJ, Xiao Y, Hill JM. Nitric Acid Functionalization of Petroleum Coke to Access Inherent Sulfur. Catalysts. 2020; 10(2):259. https://doi.org/10.3390/catal10020259

Chicago/Turabian Style

Huang, Qing, Annelisa S. Schafranski, Melanie J. Hazlett, Ye Xiao, and Josephine M. Hill 2020. "Nitric Acid Functionalization of Petroleum Coke to Access Inherent Sulfur" Catalysts 10, no. 2: 259. https://doi.org/10.3390/catal10020259

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