Production of Gasolines and Monocyclic Aromatic Hydrocarbons: From Fossil Raw Materials to Green Processes

Development of Aromatic Organic Materials for High-Performance Lithium-Ion Batteries: Strategies, Advances and Future Perspectives

Ever since lithium-ion batteries (LIBs) were successfully commercialized, aromatic compounds have attended every turning point in optimizing electrolytes, separators, and even electrode materials. However, the contribution of aromatic compounds has always been neglected compared to other advanced materials. At the same time, designing next-generation LIBs with higher flexibility, solid-state electrolytes, high energy density, and better Coulombic Efficiency (CE) has imposed stricter duties on aromatic components. In this review, we first systematically introduce the history of aromatic compounds that promote the development of LIBs. Typical applications of aromatic compounds in LIBs (e.g., separators, electrolytes, binders, and electrodes) are discussed in detail, and corresponding design characteristics are systematically analyzed. Finally, we suppose conjectures and prospects orientally designing aromatic compounds in the next generation LIBs.

Maximizing aromatic hydrocarbon production through catalytic pyrolysis of lignocellulosic residues over ZSM-5 zeolite using both batch and continuous reaction systems

This study investigates the influence of lignocellulosic biomass properties on aromatic hydrocarbon (AR) production by catalytic pyrolysis using a ZSM-5 zeolite as catalyst in a fixed-bed reactor. First, using a batch reaction system, vine and olive pruning, oak, and wheat straw were tested as feedstocks. A high lignin content in the biomass increased both char yield and bio-oil oxygen content, although not affecting AR production. In contrast, a high alkali and alkaline metal content reduced the AR yield. Oak was selected for the catalyst-bed temperature optimisation in a continuous reactor, as this biomass led to a low char yield and a bio-oil with a reduced oxygen content and a significant AR share. The highest AR carbon yield (15.1 wt% during the first hour of reaction) was achieved at 450 °C. Higher temperatures (500 °C) promoted severe cracking reactions leading to gases, while lower temperatures (400 °C) provoked a faster catalyst deactivation due to enhanced deposition of carbonaceous matter with a higher concentration of oxygenated oligomeric/heavy species. AR formation from light oxygenates, followed by the oligomerization/cyclization/aromatization pathway, is affected earlier along the time on stream than through Diels-Alder condensation reactions.

Highly Efficient Separation of Toluene and n-Heptane by Amorphous Cucurbit[7]uril Solids

Separating toluene from n-heptane is a challenging task in the petroleum industry. Traditional methods face problems including elevated energy usage, intricate technical procedures, and residual extractants. Herein, we developed an environmentally friendly, low energy consuming and economically efficient adsorption separation method. This study employed cucurbit[7]uril (Q[7]) as an adsorbent to efficiently separate toluene from a mixture of toluene and n-heptane. The purity of toluene was obtained to be 99.38 % from the mixed vapors and 99.65 % from the mixed liquids. The kinetic experiment results demonstrate that the adsorption behavior of toluene was chemisorption. Density functional theory calculations show that the structure of toluene@Q[7] is more stable. In addition, vacuum heating can remove toluene from the Q[7] cavity, resulting in a guest-free Q[7], which can be repeated for the adsorption separation process without loss of performance. This study has the potential value of addressing the pressing need for efficient resource utilization in light of diminishing petroleum supplies.

Impacts of Linear Alkylbenzene (LABs) on ecosystems: Detection, fate and remediation

This review article provides a thorough examination of an interaction between linear alkylbenzenes (LABs) and ecosystems. The review covers various aspects of LABs' impact on ecosystems, focusing on detection and treatment strategies to mitigate ecological consequences. It delves into LABs' role as molecular markers for sewage pollution, their physicochemical properties contributing to persistence, and their effects on aquatic and terrestrial organisms, including disruptions to endocrine systems. The diverse sources of LABs, including domestic wastewater and industrial effluents, are explored, along with their ratios in different matrices for assessing contamination origins. Biodegradation pathways of LABs, both aerobic and anaerobic, are scrutinized, considering their interaction with microbes. Distribution patterns in aquatic environments are discussed, encompassing sediment, water, sewage, and soils. An investigation is conducted on the relationship between LABs and total organic carbon (TOC) as a means of evaluating sewage pollution. It is assessed how sewage treatment facilities (STPs) contribute to biodegradation.

New perspectives on the anaerobic degradation of BTEX: Mechanisms, pathways, and intermediates

Aromatic hydrocarbons like benzene, toluene, xylene, and ethylbenzene (BTEX) can escape into the environment from oil and gas operations and manufacturing industries posing significant health risks to humans and wildlife. Unlike conventional clean-up methods used, biological approaches such as bioremediation can provide a more energy and labour-efficient and environmentally friendly option for sensitive areas such as nature reserves and cities, protecting biodiversity and public health. BTEX contamination is often concentrated in the subsurface of these locations where oxygen is rapidly depleted, and biodegradation relies on anaerobic processes. Thus, it is critical to understand the anaerobic biodegradation characteristics as it has not been explored to a major extent. This review presents novel insights into the degradation mechanisms under anaerobic conditions and presents a detailed description and interconnection between them. BTEX degradation can follow four activation mechanisms: hydroxylation, carboxylation, methylation, and fumarate addition. Hydroxylation is one of the mechanisms that explains the transformation of benzene into phenol, toluene into benzyl alcohol or p-cresol, and ethylbenzene into 1-phenylethanol. Carboxylation to benzoate is thought to be the primary mechanism of degradation for benzene. Despite being poorly understood, benzene methylation has been also reported. Moreover, fumarate addition is the most widely reported mechanism, present in toluene, ethylbenzene, and xylene degradation. Further research efforts are required to better elucidate new and current alternative catabolic pathways. Likewise, a comprehensive analysis of the enzymes involved as well as the development of advance tools such as omic tools can reveal bottlenecks degradation steps and create more effective on-site strategies to address BTEX pollution.

Photocatalytic Upcycling and Depolymerization of Vinyl Polymers

Photocatalytic upcycling and depolymerization of vinyl polymers have emerged as promising strategies to combat plastic pollution and promote a circular economy. This mini review critically summarizes current developments in the upcycling and degradation of vinyl polymers including polystyrene and poly(meth)acrylates. Of these material classes, polymethacrylates possess the unique possibility to undergo a photocatalytic depolymerization back to monomer under thermodynamically favourable conditions, thus presenting significant advantages over traditional thermal strategies. Our perspective on current formidable challenges and potential future directions are also discussed.

High-solution emission characters and health risks of volatile organic compounds for sprayers in automobile repair industries

The increasing automobile repair industries (ARIs) with spray facilities have become an important volatile organic compound (VOC) pollution source in China. However, the VOC health risk assessment for long-term exposure in ARIs has not been well characterized. In this study, though sampled VOCs from 51 typical ARIs in Beijing, the relationship between emission patterns, average daily exposure concentrations (EC), and health risks was comprehensively analyzed with the health assessment method. Results showed that concentrations of 117 VOCs from the samples ranged from 68.53 to 19863.32 μg·m-3, while the ARI operator's daily VOC inhalation EC was 11.24-1460.70 μg·m-3. The organic VOC (OVOC) concentration accounted for 73.16 ~ 94.52% in the solvent-based paint workshops, while aromatics were the main VOC component in water-based paint spraying (WPS) workshops, accounting for 70.08%, respectively. And the method of inhalation exposure health risk assessment was firstly used to evaluate carcinogenicity and non-carcinogenicity risk for sprayers in ARIs. The cumulative lifetime carcinogenic risk (LCR) for 24 sampled VOCs were within acceptable ranges, while the mean hazard index (HI) for 1 year with 44 sampled VOCs was over 1. Among them, ethyl alcohol had a high carcinogenic risk in both mixed water-based paint (MP) and solvent-based paint workshops. The mean HI associated with aromatics were 2.88E - 3 and 4.30E - 3 for 1 h in MP and WPS workshops. O-ethyl toluene and acetone are VOC components that need to be paid attention to in future paint raw materials and spraying operations. Our study will provide the important references for the standard of VOC occupational exposure health limits in ARIs.

A Study of the Pyrolysis Products of Kraft Lignin

In order to valorize lignin wastes to produce useful aromatic compounds, the thermal degradation pyrolysis of Kraft lignin in the absence of catalysts has been investigated at 350, 450, and 550 °C. The high content of sulfur in the fresh sample led to the formation of S-containing compounds in products whose evolution in the gas phase was monitored through GC-MS analysis. Pyrolytic gas is rich in CH4, CO, CO2, and H2S with the presence of other sulfur compounds in smaller amounts (i.e., CH3SH, CH3-S-CH3, SO2, COS, and CS2). Biochar morphology and elemental composition have been investigated by means of SEM and EDX. The carbon content reaches ~90% after pyrolysis at 550 °C, while the oxygen content showed a decreasing trend with increasing temperature. From GC-MS analysis, bio-oil resulted rich in alkyl-alkoxy phenols, together with (alkyl)dihydroxy benzenes and minor amounts of hydrocarbons and sulfur compounds. NaOH/H2O and EtOH/H2O extraction were performed with the aim of extracting phenolic-like compounds. Sodium hydroxide solution allowed a better but still incomplete extraction of phenolic compounds, leaving a bio-oil richer in sulfur.

Advancements in the Conversion of Lipid-Rich Biowastes and Lignocellulosic Residues into High-Quality Road and Jet Biofuels Using Nanomaterials as Catalysts

At present, the majority of available road and jet biofuels are produced from oleochemical feedstocks that include vegetable oils and biowastes such as waste cooking oils and animal fats. Additionally, one of the most promising ways to achieve long-term environmental goals is to sustainably use lignocellulosic residues. These resources must be treated through a deoxygenation process and subsequent upgrading processes to obtain high-quality road and jet biofuels. Accordingly, in this review, we explore recent advancements in the deoxygenation of oleochemical and lignocellulosic feedstocks in the absence of hydrogen to produce high-quality road and jet biofuels, mainly focusing on the use of nanomaterials as catalysts and the valorization of lipid-rich biowastes and lignocellulosic residues. As a result, we found that regardless of the catalyst particle size, the coexistence of basic sites and weak/medium acid sites is highly important in catalytic systems. Basic sites can enhance the removal of oxygenates via decarboxylation and decarbonylation reactions and inhibit coke formation, while weak/medium acid sites can enhance the cracking reaction. Additionally, the extraction of value-added derivatives from lignocellulosic residues and their subsequent upgrade require the use of advanced methods such as the lignin-first approach and condensation reactions.

Novel Short Process for p-Xylene Production Based on the Selectivity Intensification of Toluene Methylation with Methanol

Toluene methylation using methanol offers a high potential molecular engineering process to produce p-xylene (PX) based on shape-selective catalysts. To further improve the process economics, a novel short process was proposed by reducing the high-energy consumption separation of xylene isomers in existing processes since the PX selectivity of the xylene isomers can be enhanced more than the industrial product quality of 99.7%. The PX selectivity intensification was achieved as a result of decreased contact time by considering factors such as the feed ratio, diluents, temperature, and pressure in a toluene methylation reactor. This proposed short process indicated that the reactor effluent could be purified only through the two conventional distillation towers by removing the methanol recovery and separation of xylene isomers. The raw material utilization, energy consumption, and economic data were also analyzed for the six contrastive cases. The short process using catalyst Si-Mg-P-La/ZSM-5 exhibited the highest effective utilization rates of 96.27 and 95.50% for toluene and methanol, respectively. The short process also showed a good economic value in terms of capital investment and operating costs due to the multistage reactor without benzene byproducts. Thus, the obtained total annual cost (TAC) value of 13 848.1 k$·year^-1 was 68.9 and 87.9% of the two existing processes.