Autoxidation is a conversion pathway that has the potential to add value to multinuclear aromatic-rich coal liquids, heavy oils and bitumens, which are typically considered low-value liquids. In particular, autoxidation of these heavy materials could lead to products that may have petrochemical values, e.g., lubricity improvers and emulsifiers. Proper assessment of an oxidative transformation to ring-open the multinuclear aromatics present in heavy feeds relies on the understanding of the fundamentals of aromatic oxidation. This work reviews the selective oxidation chemistry of atoms that form part of an aromatic ring structure using oxygen (O₂) as oxidant, i.e., the oxidation of aromatic carbons as well as heteroatoms contained in an aromatic ring. Examples of industrially relevant oxidations of aromatic and heterocyclic aromatic hydrocarbons are provided. The requirements to produce oxygenates involving the selective cleavage of the ring C–C bonds, as well as competing non-selective oxidation reactions are discussed. On the other hand, the Clar formalism, i.e., a rule that describes the stability of polycyclic systems, assists the interpretation of the reactivity of multinuclear aromatics towards oxidation. Two aspects are developed. First, since the interaction of oxygen with aromatic hydrocarbons depends on their structure, oxidation chemistries which are fundamentally different are possible, namely, transannular oxygen addition, oxygen addition to a carbon–carbon double bond, or free radical chemistry. Second, hydrogen abstraction is not necessary for the initiation of the oxidation of aromatics compared to that of aliphatics.

中文翻译：

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芳烃的自氧化

自氧化是一种转化途径，有可能为多核富含芳烃的煤液，重油和沥青（通常被认为是低值液体）增加价值。特别是，这些重质材料的自氧化作用可能导致产生具有石化价值的产品，例如润滑性改进剂和乳化剂。对重质进料中存在的多核芳烃开环氧化转化的正确评估取决于对芳烃氧化基本原理的理解。这项工作回顾了使用氧（O ₂形成芳香环结构的一部分的原子的选择性氧化化学）作为氧化剂，即芳族碳以及芳环中所含杂原子的氧化。提供了与工业相关的芳族和杂环芳族烃的氧化的实例。讨论了产生含氧化合物的要求，其中涉及环C-C键的选择性裂解以及竞争性的非选择性氧化反应。另一方面，Clar形式主义，即描述多环系统稳定性的规则，有助于解释多核芳烃对氧化的反应性。发展了两个方面。首先，由于氧与芳烃的相互作用取决于它们的结构，因此根本上可能不同的氧化化学性质是可能的，即，环过氧，碳-碳双键中的氧，或自由基化学。其次，与脂族相比，夺氢不是引发芳族化合物氧化的必要条件。