Formation Mechanism of Benzo(a)pyrene: One of the Most Carcinogenic Polycyclic Aromatic Hydrocarbons (PAH)

Abstract

The formation of polycyclic aromatic hydrocarbons (PAHs) is a strong global concern due to their harmful effects. To help the reduction of their emissions, a crucial understanding of their formation and a deep exploration of their growth mechanism is required. In the present work, the formation of benzo(a)pyrene was investigated computationally employing chrysene and benz(a)anthracene as starting materials. It was assumed a type of methyl addition/cyclization (MAC) was the valid growth mechanism in this case. Consequently, the reactions implied addition reactions, ring closures, hydrogen abstractions and intramolecular hydrogen shifts. These steps of the mechanism were computed to explore benzo(a)pyene formation. The corresponding energies of the chemical species were determined via hybrid density funcional theory (DFT), B3LYP/6-31+G(d,p) and M06-2X/6-311++G(d,p). Results showed that the two reaction routes had very similar trends energetically, the difference between the energy levels of the corresponding molecules was just 6.13 kJ/mol on average. The most stable structure was obtained in the benzo(a)anthracene pathway.

Reduction strategies for polycyclic aromatic hydrocarbons in processed foods

“…The formation of PAHs in food is an extremely complex process. Hydrogen abstraction and acetylene addition (HACA), Diels–Alder reaction, phenyl‐addition‐cyclization (PAC), and methyl addition/cyclization (MAC) are considered as the possible reaction routes of PAHs formation (Kislov et al., 2013; Reizer et al., 2019; Shukla & Koshi, 2012). Although the precise mechanism of PAHs formation is still not specified, there are three possible mechanisms regarding the pyrolysis of hydrocarbons in food, and the combustion of cooking fuel and fat droplet on open flame are widely accepted as the leading cause of PAHs formation in processed food (Alomirah et al., 2011; Singh et al., 2020; Wang et al., 2018).…”

Recent Advances in Methods for the Recovery of Carbon Nanominerals and Polyaromatic Hydrocarbons from Coal Fly Ash and Their Emerging Applications

“…Here, the presence of the phenanthrene type of aromatic compound in feed coal supports this view while considering the majority of such compounds. The formation of a higher amount of 4-, 5-, and 6-ring PAHs in CFA takes place through the polymerization process caused by bond cleavage; free radical condensation occurred as a result of chemical fluctuations of unstable hydrocarbons [148].…”

Isoorientin Attenuated the Pyroptotic Hepatocyte Damage Induced by Benzo[a]pyrene via ROS/NF-κB/NLRP3/Caspase-1 Signaling Pathway

“…Benzo[a]pyrene (BaP, Figure 1B), is a group I carcinogen and possesses strong carcinogenicity, teratogenicity, and genotoxicity [8][9][10]. It is widespread in the high temperature heat processed foods, such as smoked fish, sausage, fried chicken, vegetable oil, and cereals [11].…”