Mild oxidation of Yanshan petroleum coke with aqueous sodium hypochlorite

Abstract

Yanshan petroleum coke (YPC) was subjected to oxidation with aqueous sodium hypochlorite under mild conditions followed by subsequent solvent extraction to afford various arenecarboxylic acids (ACAs). In total, 77 compounds were identified with a chromatograph/mass spectrometer, which can be classified into 14 group components. Among them, benzenepolycarboxylic acids (BPCAs) are the most abundant. The results indicate that YPC is rich in condensed aromatic moieties. The formation of O2− is vital to the decomposition of the condensed aromatic moieties in YPC to ACAs. Chlorine-containing BPCAs with more than 2 carboxylic groups were not detected, manifesting that ACA chlorination proceeded via Cl2 addition and subsequent HCl elimination rather than Cl substitution. BPCAs and heavier ACAs were produced from condensed aromatics and substituted arenes, respectively, in YPC. Benzenecarboxylic acids (BCAs) and their chlorides can be enriched into different fractions by solvent extraction, facilitating the YPC utilization as a chemical resource. Hence, this investigation provides a promising approach for obtaining BCAs, especially BPCAs, from YPC and for understanding aromatic structural features in organic matter of YPC.