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 (O 2) 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 CC 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.

Ring-opening conversion of multinuclear aromatics can be used to upgrade heavy aromatic oils to lighter products, and it is usually performed reductively with H 2 . Oxidative ring-opening is an alternative strategy that involves three steps: (i) oxidation of multinuclear aromatics to quinonoids, (ii) further oxidation and ring-opening to produce aromatic carboxylic acids, and (iii) decarboxylation of aromatic carboxylic acids. In the last step, decomposition by ketonization is an undesirable side reaction that leads to a ring-closed product. Selectivity control during aromatic carboxylic acid decomposition was investigated using biphenyl-2-carboxylic acid, biphenyl-2,2′-dicarboxylic acid, zinc(II) biphenyl-2-carboxylate, and zinc(II) biphenyl-2,2′-dicarboxylate. The reaction networks of thermal decomposition of the aromatic carboxylic acids were determined. Decomposition of biphenyl-2-carboxylic acid took place mainly by decarboxylation to produce biphenyl, dehydration and ringclosure to produce fluorenone, and the formation of diphenic anhydride as intermediate product leading to fluorenone. Decomposition of biphenyl-2,2′-dicarboxylic acid proceeded through decarboxylation to biphenyl-2-carboxylic acid as intermediate, as well as two seemingly related pathways, leading to the formation of a hydroxy-fluorenone and a cyclic trione. Over the temperature range from 340 °C to 400 °C, thermal decomposition invariably resulted in a higher ketonization than decarboxylation selectivity. Decomposition of the analogous zinc carboxylates demonstrated that ketonization could be suppressed and the most abundant products were biphenyl > fluorenone > fluorene. It was possible to achieve a biphenyl (decarboxylation) to fluorenone (ketonization) selectivity ratio of 17:1 during batch reactor decomposition of zinc(II) biphenyl-2,2′-dicarboxylate at 380 °C. Reaction stoichiometry indicated that water should affect selectivity, which is consistent with observations in the literature, but this aspect was not investigated further.

Front-end design decisions for a process to produce sustainable aviation turbine fuel from waste materials were presented. The design employs distributed conversion of wastes to oils, which are then transported to a central facility for gasification, syngas cleaning, Fischer-Tropsch synthesis and refining, that is, a spoke-and-hub approach. Different aspects of the front-end design, that is, the steps up to syngas cleaning, were evaluated. The evaluation employed a combination of case studies, calculations, experimental investigations, and literature review. The supply of sustainable aviation fuel (SAF) as a 50:50 mixture of wastederived and petroleum-derived kerosene to meet the demand of an international airport (Pearson, Toronto) was employed as case study. The amount of raw material required made it impractical to make use of only one type of waste. Using the same set of assumptions, it was shown that in terms of cumulative transport distance required, a spoke-and-hub approach was twice as efficient as centralized processing only. Technologies for decentralized production of oils were assessed, and oils produced by pyrolysis and hydrothermal liquefaction (HTL) in pilot-scale and larger facilities were procured and characterized. These oils were within the broader compositional space of pyrolysis oils and HTL oils reported in laboratory studies. The oil compositions were employed to study the impact of oil composition on entrained flow gasification. Thermodynamic equilibrium calculations of pyrolysis and HTL oil entrained flow gasification resulted in H 2 / CO ratios of syngas and O 2 consumption rates in a narrow range, despite the diversity of feeds. At the same time, to produce an equal molar amount of syngas (H 2 + CO), less HTL oil than pyrolysis oil was required as feed. Gas cleaning technologies were reviewed to ascertain types of contaminants anticipated after gasification, their removal effectiveness, and Fischer-Tropsch catalyst poisoning 1763

Viscosity is an important parameter to assess heavy oil and bitumen upgrading operations, such as bitumen dilution to meet pipeline viscosity specification limits. In conceptual design studies that involve blending of high-and low-viscosity materials, the experimental measurement of viscosity is impractical; therefore, such studies employ mixing rules to estimate mixture viscosity. Mixing rules for conceptual design evaluations where limited or no information apart from the viscosity and density of the bitumen and solvents is available were of interest. This study determined which viscosity mixing rules could be used with such limited input, what the predictive errors were, whether the performance of those mixing rules were measurably affected by changes in chemical composition, and if mixing rules could be applied at the <10 wt % solvent concentration in bitumen. Binary mixtures of 1−10 wt % of six different solvents (1-methylnaphthalene, decahydronaphthalene, 1,2,3,4-tetrahydronaphthalene, butylcyclohexane, butylbenzene, and n-decane) and Athabasca bitumen were prepared, and their viscosity, density, and refractive index were measured at 303, 313, and 333 K (30, 40, and 60 °C) and atmospheric pressure. The performance of mixing rules in predicting these properties for the binary mixtures at low solvent concentration was evaluated. It was found that the simple mixing rule, log [log (ν m + 0.7)] = Σw i log [log (ν i + 0.7)], and that by Miadonye et al. (Petrol. Sci. Technol. 2000, 18, 1−14) consistently gave the better viscosity estimation with an absolute average relative deviation (AARD) of around 30%. Within this uncertainty, there was no evidence indicating that the mixing rules could not be used for viscosity prediction of bitumen−solvent mixtures at low dilution levels. The mixing rules appeared not to be affected by the chemical nature of the solvent, and if it had an effect, it was of the same order or less than the uncertainty of viscosity prediction.

Reactions of 2,2‐dimethylaziridine with benzohydroximoyl chlorides [ArC(Cl)NOH] give aziridinylbenzaldoximes 1. It has been found that the aziridine ring in these compounds undergoes ring opening in hydrogen chloride‐dioxane solution to give (Z)‐N‐hydroxy‐N′‐(2‐chloro‐2‐methylpropyl)benzenecarboximidamides [ArC(NHCH2CR1R2Cl)NOH, 4]. Treatment of 1 with hydrochloric acid followed by neutralization with aqueous sodium hydroxide gave 6,6‐dimethyl‐3‐aryl‐1,2,4‐oxadiazines 2. Reaction of 4 with sodium hydride in dioxane gave 5‐isopropyl‐3‐aryl‐4,5‐dihydro‐1,2,4‐oxadiazoles 5. Reaction of the 4,5‐dihydro‐1,2,4‐oxadiazoles 5 with N‐chlorosuccinimide gave the heteroaromatic 1,2,4‐oxadiazoles 6. It is suggested that reactions of 4 with sodium hydride in dioxane solution involve the conjugate base of 4 which undergoes a 1,2‐hydride shift that is concerted with loss of chloride ion. In aqueous sodium hydroxide solution it is suggested that the conjugate base of 4 undergoes ionization of the chlorine atom followed by nucleophilic attack by the oximate anion.