Aromatic Content Research Articles

Study on coal pyrolysis characteristics by combining different pyrolysis reactors

The pyrolysis process of Shendong coal (SD) was first studied by combining the characteristics of thermal gravimetric (TG), pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and Gray-King assay (G-K). The results show that the order of coke yields is G-K (76.35% (mass))>TG (73.11% (mass))>Py (70.03% (mass)). G-K coke yield caused by condensation reaction and secondary reaction accounts for 3.08% (mass) and 3.24% (mass), respectively. Compared with slow pyrolysis, fast pyrolysis has stronger fracture ability to coal molecules and can obtain more O-compounds, mono-ring aromatics and aliphatics. Especially, the content of phenolics increases significantly from 15.49% to 35.17%, but the content of multi-ring aromatics decreases from 23.13% to 2.36%. By comparing the compositions of Py primary tar and G-K final tar, it is found that secondary reactions occurred during G-K pyrolysis process include the cleavage of alkane and esters, condensation of mono-ring aromatics with low carbon alkene, ring opening, isomerization of tri-ring aromatics, hydrogenation of aromatics and acids.

Microwave catalytic co-pyrolysis of microalgae and high density polyethylene over activated carbon supported bimetallic: Characteristics and bio-oil analysis

Three activated carbon (AC) supported bimetallic catalysts (Ce-Fe/AC, Ce-Ni/AC, Ce-Cu/AC) were prepared, and the catalysts' impacts on the microwave co-pyrolysis of Chlorella vulgaris (C. vulgaris) and high density polyethylene (HDPE) (mixing ratio of 1:1, C1HP1) were explored. The findings indicated that the catalysts promoted the co-pyrolysis of C1HP1 substantially at 40 % and 50 % additions. The minimum reaction time (2945 s) was observed at 40 % Ce–Fe/AC. Compared to the C1HP1 group, Ce-Fe/AC groups exhibited a pronounced promotional impact on bio-oil production, with the maximum bio-oil yield (25.8 %) catalyzed by 30 % Ce–Fe/AC. Furthermore, the catalyst's high hydrogenation activity and deoxygenation promoted the formation of H2O, NH3 and HCN, achieving over 40 % efficiencies in deoxygenation and denitrification for bio-oil. 40 % Ce–Cu/AC exhibited superior performance with the highest hydrocarbon (67.43 %) and aromatic hydrocarbon content (50.75 %), as well as leading deoxygenation (44.38 %) and nitrogen removal (58.63 %) efficiency among the AC supported bimetallic catalysts.

Unlocking the potential of rice husk pyrolysis oil: Dual production of high-energy solid fuel and Fe²⁺ detecting carbon nanodots for environmental application

The urgent need for sustainable energy solutions and environmental monitoring necessitates innovative approaches to biomass utilization. This study explores unlocking the potential of rice husk pyrolysis oil for dual applications: producing high-energy solid fuel and environmentally sensitive carbon nanodots (B-CDs). Slow pyrolysis of rice husk oil, followed by atmospheric distillation, transforms the oil into bio-coal with a high calorific value of 29.85 MJ/kg, significant aliphatic and aromatic carbon content, lowest ash content, and abundant oxygen functional groups, making it a viable fossil fuel alternative. Further, oxidative crystalline cutting and surface modification of this bio-coal yield B-CDs that exhibit blue fluorescence with a quantum yield of 41 %, an average size of 3.4 nm, and excellent photostability and hydrophilicity. Notably, these B-CDs are self-doped with nitrogen on their surface, enhancing their functionality. They demonstrate high sensitivity for Fe²⁺ detection, with a limit of detection (LOD) of 0.34 μM over a linear range of 0–100 μM, and a strong response to alkaline conditions. Validation experiments in tap and seawater samples confirmed the practical environmental applications of B-CDs. This study not only contributes to the advancement of pyrolysis oil as a source of fuel energy but also emphasizes the production of valuable carbon nanomaterials for environmental application.

All-in-one fabrication of NiO nanorods/carbon-containing porous catalytic polymer membranes for persulfate-facilitated oxidation-adsorption of diclofenac in flow–through

We introduce a novel all-in-one fabrication method for porous catalytic polyethersulfone (PES) membranes containing NiO nanorods and carbon nanoparticles. This method is based on the sonochemical in situ solidification of a metal salt with NaBH4 in presence of carbon particles in a PES-containing casting-reaction solution, directly followed by membrane preparation via film casting cum phase separation. In the catalytic flow-through degradation of 20 mg/L aqueous diclofenac with persulfate as oxidant, an as-prepared NiO-carbon-PES membrane achieved a 99 % aromatic content removal degree at a residence time of only 1.6 s. In comparison, NiO and CuO membranes without carbon particles exhibited < 40 % aromatic removal degrees. The high performance was attributed to a degradation-induced adsorption, with a diclofenac removal capacity of 950 mg/g of incorporated carbon particles. We demonstrated that diclofenac is catalytically mineralized in the membrane at incorporated NiO nanorods, followed by adsorption of remaining degradation products at nearby carbon particles. Our data further suggests that reducing NiO to Ni(0) via a membrane pretreatment shifts the catalytic persulfate activation from a radicaltoa non-radical pathway, and that HCO3– can function as sacrificial electron donor for Ni(0). This completely mitigated nickel leaching from the membrane in contact to persulfate. Moreover, even in the presence of NaHCO3 and NaCl, a Ni(0)–carbon–PES membrane consistently eliminated ∼ 90 % of the total organic carbon (TOC) from a 2 mg/L diclofenac feed containing persulfate in single-pass flow-through mode (continuously for 5 h, respectively for 500 L/m2 permeate volume), with no detectable release of degradation products or any nickel leaching.

Catalytic conversion of biomass pyrolysis volatiles over composite catalysts of activated carbon and HY zeolite

Bio-oil has complex compositions and high oxygen content, which restricts its high-value utilization. Commercial activated carbon (AC) and HY zeolite were used as composite catalysts to study their effect on pyrolysis volatiles from rice straw and poplar sawdust by changing the mixing modes of two catalysts. The results showed that the loading modes of AC and HY zeolite obviously affected the products distribution and bio-oil components. The lowest yield of bio-oil was obtained when HY zeolite and AC were mechanically mixed at a mass ratio of 1:1 (YACM). But the loading mode of YACM was beneficial to the deoxidation and aromatic hydrocarbon generation. Under the mode of YACM, the aromatics content in rice straw and poplar sawdust bio-oil can be increased from 13.8% and 8.0% without catalyst to 56.4% and 53.1%, respectively. However, the layered loading with upper HY zeolite and lower AC (YTACL) was favorable for formation of phenolic compounds. The selectivity to monocyclic and bicyclic aromatic hydrocarbons followed the order of YTACL > ACTYL > YACM, and YACM > ACTYL > YTACL, respectively. Compared with HY zeolite, AC catalyst possessed smaller pore size and fewer acidity, and the active sites of AC were conducive to rearrangement of furan compounds to generate cyclopentanone, 2-cyclopentenone and methyl-cyclopentenone, and further rearrangement to form phenol. Therefore, the loading mode of YTACL exhibited a promotion effect on the formation of phenol, cresol, toluene, ethylbenzene and p-xylene. The strong acidic sites of HY zeolite were favorable for the aromatization, so the loading mode of ACTYL had good selectivity to the formation of naphthalene, methylnaphthalene, anthracene and pyrene. This work will provide a guide for products regulation from biomass pyrolysis and enrich aromatics and phenols in bio-oil.

Neopetasan, the main component of the essential oil from Cyperus sesquiflorus (Cyperaceae)

ABSTRACT Cyperus sesquiflorus is commonly called fragrant kyllinga, fragrant spikesedge, or fragrant flatsedge. It is a cespitose perennial herb with a Pantropical distribution. In Brazil, it is a native species, being commonly named fragrant grass due to its aromatic content. In this study, the essential oil (EO) of C. sesquiflorus was extracted by hydrodistillation with a Clevenger apparatus. Yields of the samples ranged between 0.12% and 0.27% (v/w) oils from fresh and dehydrated whole flowering plants (with roots) and the oil was analyzed by Gas Chromatography/-Mass spectrometry/flame ionization detection (GC-MS/FID) and Gas chromatography/Mass spectroscopy (GC/MS). The main constituent of the oil, neopetasan (3S,4aR,5S)-4a,5-dimethyl-3-(prop-1-en-2-yl)-4,4a,5,6,7,8 hexahydronaphthalen-2(3 H)-one, was isolated by preparative thin layer chromatography (PTLC) and its structure was elucidated by extensive one- and two-dimensional nuclear magnetic resonance (1D/2D-NMR) (COSY, HSQC, HMBC, and NOESY) and Fourier transform infrared (FTIR) spectroscopy in combination with MS and comparison with literature data.

Investigating the coking performance of ethylene residue pitch components

Ethylene residue pitch (ETP, the heavy component in ethylene residue tar) is widely used as a preferred raw material for preparing petroleum-based artificial carbon materials characterized by high carbon content, high aromaticity, and low heteroatom (S, N) content. To investigate the coking properties of ETP, eight components of ETP (four soluble and four insoluble components) were obtained via extraction and separation using methanol, n-butanol, n-hexane, and dimethyl sulfoxide as solvents. The thermal conversion (temperature = 500 °C) and carbonization treatment (temperature =1400 °C) were carried out on each pitch component. The basic physical properties of ETP components were observed using infrared spectroscopy, thermogravimetric analysis, and 1H-NMR. The microstructure of the petroleum-based pitch coke was studied using polarizing microscopy, X-ray single crystal diffraction (XRD), Raman spectroscopy, and scanning electron microscopy. The aromaticity of the insoluble components in ETP was slightly higher than that of soluble components, and the insoluble components had slightly fewer branching chains than those in soluble components. The microstrength of the ETP coke obtained using insoluble components was higher than that obtained using soluble components, and the true density of ETP coke HS-C was as high as 2.0554 g/cm3.

Statistical analysis of fuel combustion and emissions considering the adverse effects of investment economic environment: Exploring alternatives amid oil prices Swings, digital economy, and local market inflation

The depletion of natural gas reserves, combined with rising oil prices, local market inflation, and concerns about pollution, has accelerated the search for alternative energy sources. As a result, research on turbines and internal combustion engines for electricity generation is increasingly focusing on using vaporized ethanol as a fuel substitute. However, the high cost of analyzing the chemical composition of these fuels often leads to an oversight of their impact on combustion characteristics, such as flame behavior, emission profiles, and temperature distribution.This study employs a statistical approach to assess the combustion and emission characteristics of biofuels, aiming to find suitable alternatives to petroleum-based fuels. By integrating considerations of oil price fluctuations and the digital economy's impact, the research proposes a cost-effective method for evaluating the chemical makeup of vaporized fuels and their effects on post-combustion pollution.Experimental data reveal that alternative fuels can offer stable ignition performance and lower pollution levels, contingent on their specific properties. Fuels with high aromatic content and viscosity tend to produce significant CO emissions, while reducing these characteristics may increase CO2 production. The study also highlights the challenge of simultaneously reducing both CO and NOx emissions. Additionally, the findings show that petroleum gasoline, due to its lower volatility, has favorable fire safety properties and generates fewer pollutants.In the context of economic pressures from rising oil prices and inflation, this research underscores the importance of exploring biofuels as viable, sustainable alternatives for the future energy landscape.

Influence of banana peel waste biomass ratio in Co-pyrolysis of waste plastics to regulate aromatic content and oxygenated compounds: A study of liquid product characterization and its CI engine performance

We have reported the importance of biomass ratio in the co-pyrolysis of waste plastics to regulate the aromatic content and oxygenated compounds in hydrocarbon-rich fuels for enhancing engine performance. The study revealed that changing biomass to plastic ratio can control aromatic compositional change. The obtained product was characterized using different instrumentation techniques, such as NMR, FTIR, GCMS, etc., to identify the hydrocarbon types in the liquid product. Results revealed that it contains C8-C24 range carbon compounds with dominating aromatics compounds, as confirmed by 1H NMR and FTIR analysis. The pyro-oils contain different hydrocarbons: olefins, paraffin, aromatics, esters, and alcohols. It was observed that the presence of biomass in co-pyrolysis produces oxygenated compounds up to ∼12.08 % and also enhances calorific value up to 55.4 MJ/kg from 48.3 MJ/kg due to the presence of longer hydrocarbon chains of esters in pyro-oil. Biomass co-pyrolysis also improved the fuel properties such as pour point (<-25°C) and 4°C increment in flash point. Engine performance showed that blending biomass pyro-oil obtained from B25PS75 reduced fuel consumption and increased BTE.

Experimental and numerical study of the decomposition, product spectrum, and sooting properties of adamantane fuels

This work combined experimental measurements with two theoretical approaches, reactive Molecular Dynamics (MD) simulations and Quantum Mechanics (QM) calculations, to investigate the combustion and sooting properties of three adamantane fuels, adamantane (AD), 1,3-dimethyl-adamantane (DMAD), and 1-ethyl-adamantane (EAD). These fuels were selected since the adamantane fuel family can potentially be used as sustainable aviation fuels and comparing these fuels would reveal the effects of side chain on their combustion and sooting properties. We determined the bond dissociation energies of the three test fuels using QM calculations and found that the functionalized side chains have the weakest bonds and their presence only slightly affects the bond strength in the AD multi-cyclic core. We performed pyrolysis simulations for all three fuels using ReaxFF-based MD simulations and found that DMAD and EAD have higher decomposition rates than AD and also generate more high-molecular-weight products. For all three fuels, these large products were observed to contribute significantly to hydrocarbon growth processes, which lead to large soot nucleating species and even soot-like structures. A higher yield of such soot nucleating compounds was found during the pyrolysis of DMAD and EAD than AD since the decomposition products of DMAD and EAD are more branched and those of AD have mostly straight chains. These theoretical analyses were supported by experimental measurements of yield-based sooting tendencies, which suggest that DMAD and EAD are sootier than AD and that all three fuels are sootier than standard alkane jet fuel surrogates but less sooty than jet fuel aromatic content.

A preliminary evaluation of how classical separation techniques affect the solid catalyst surface features during transesterification

The aim of this study was to investigate how the classical separation methods alter the solid catalyst surface structure in heterogeneous-catalyzed transesterification, viz., centrifugal and gravitational settling-in-funnel schemes, for the first time. The FTIR spectroscopy showed that while the settling system produces vivid and smooth surface shifting as a result of long-term contact with reaction products, centrifugal separation does not entirely obliterate the identity of the post-reaction catalyst surface. In addition, the SEM analysis confirmed that smaller agglomerates, which may have resulted from the dissolution of some particles and the accumulation of organic substances that clog the catalyst pore through the formation of calcium-glycerol bonds during the decantation period, were observed in the gravitational settling system; this trait could also complicate the separation and lower the desired product recovery (biodiesel). Whereas the centrifugal separation technique revealed the presence of bigger oval-shaped agglomerates, which are anticipated to possess more unoccupied active sites for efficient catalysis. As a result, centrifugal separation produces a greater biodiesel yield (87 ± 0.9%) than the settling method (76.6 ± 2%). The fuel properties of biodiesel products were characterized in terms of acid value, kinematic viscosity, cetane number, and specific gravity, of which only the cetane number does not meet the international limit due to its aromatic content. Generally, the results of this study proved that centrifuges are a more effective method of separating heterogeneous catalysts relative to the decantation system.

Study of the co-pyrolysis behavior and bio-oil characterization of walnut shell and polyethylene by thermogravimetric analyzer and bubbling fluidized bed

In the present work, co-pyrolysis experiments of walnut shell (WS), polyethylene (PE) and their blends were performed in the thermogravimetric analyzer and lab-scale bubbling fluidized bed reactor, to clarify co-pyrolysis behaviors, synergy interactions and pyrolysis oil properties. Besides, the HZSM-5 zeolite was used as the catalyst and its catalytic characteristics were studied. Results indicated that as PE mass ratio rose from 0 to 100 %, the initial temperature monotonically increased from 265.4 to 417.3 °C, while its terminal temperature progressively decreased from 668.3 to 527.5 °C, suggesting that the addition of PE was able to accelerate the pyrolysis of samples. The co-pyrolysis of blends was distinguished into three stages, with a negative interaction observed in the first stage and positive interactions found in second and third stages. Besides, in the bubbling fluidized bed experiments, the liquid phase product yield first elevated and then reduced with rising temperature, and a high temperature promoted the degradation of oxygen-containing compounds and enhanced aromatics generation. The synergistic interaction in the co-pyrolysis of WS and PE declined the liquid phase product yield while elevating the gas phase product yield. On the other hand, blending with PE facilitated the generation of alkanes and olefins, while inhibiting the contents of oxygen-containing components and aromatics, and simultaneously, the heavy oil fraction was increased. Finally, the carbon deposited on the surface of catalysts was amorphous carbons, and could be removed by oxidation process, whereas its catalytic properties progressively declined with rising cycle number, leading to a downtrend of aromatics and olefins and an opposite trend for oxygen-containing components.

Differences in humic acid structure extracted from different types of peat

ABSTRACT Peat is an organic mineral resource. Peat contains a large amount of humic acid, and extracting humic acid from peat is a way to efficiently utilize peat. This article mainly studies the effects of using woody, herbaceous, and mossy peat as raw materials on the yield, content, and especially molecular structure of humic acid extraction, including that the oxygen-containing functional groups of humic acids, aromatic carbon content, microcrystalline structure, carbon chain structure, and degree of aromatization. The results showed that the highest yield of humic acid in woody peat was 54.33%, the yield of humic acid in herbaceous peat and mossy peat are relatively low, at 44.67% and 15.00%, respectively. while the woody peat humic acid has the lowest content, that is 38.38%. The content of humic acid in herbaceous peat was 77.33%. and the content of humic acid in mossy peat is 57.85%. Through comprehensive consider, herbaceous peat is more suitable for extracting humic acid. At the same time, this article studies the molecular structures of three peat humic acids and concludes as follows. Woody peat humic acid has the highest degree of aromatization, the highest content of benzene ring, and more functional groups such as methyl, phenol, aromatic ether, carbonyl, and hydroxyl groups. The content of methoxy and methylene groups in herbaceous peat humic acid is relatively high. Through XPS characterization analysis, it was found that the main forms of oxygen element in humic acid are C = O, C-O, and -COOH, without inorganic oxygen. The humic acid extracted from different types of peat has significant differences in yield, purity, and functional group content. Compared to woody peat and mossy peat, herbaceous peat is the most suitable raw material for extracting humic acid from peat.

Experimental study on the mechanism of associated gas generation by heavy oil aquathermolysis and thermal cracking during steam injection

Previously, we proposed an innovative method for heavy oil recovery known as the ISSG-SAGD (in-situ solvent generation enhanced steam assisted gravity drainage) technique. This technology can improve heavy oil recovery efficiency, reduce steam consumption, and mitigate acid gas emissions. However, the reaction kinetic model used in numerical simulation was derived from literature reports and reasonable assumptions, lacking experimental validation. This study addresses this gap by conducting a series of experiments to investigate the mechanism of associated gas generation under steam injection conditions. We differentiated the reaction temperature window of aquathermolysis and thermal cracking based on the quantity and composition of the associated gas generated. The study revealed that aquathermolysis, occurring at 240–280℃, produces a small amount of associated gas (gasification degree of 0.32 %), predominantly CO2 (about 68 %). In contrast, thermal cracking, occurring at temperatures up to 380℃, significantly increases gas generation (gasification degree of 14.33 %), with light hydrocarbons (C1–5) constituting about 80 % of the gas produced. The reaction rate was found to be proportional to the reaction temperature and time. The SARA analysis showed that saturates and aromatics content increased, while resins and asphaltenes decreased after both reactions. A kinetic model for associated gas generation was established, and kinetic parameters such as activation energies and frequency factors were derived using the Arrhenius method. For example, the activation energy for CO2 generation increased from 18.19 kJ/mol during aquathermolysis to 147.58 kJ/mol during thermal cracking. This study provides a comprehensive understanding of the associated gas generation mechanisms and characteristics under steam injection, supporting the feasibility and potential application of the ISSG-SAGD technique in heavy oil recovery.

Changes in chemical characteristics and toxicity of fluoxetine and humic acid during chlorination

The coexistence of emerging pollutants and dissolved organic matter in wastewater complicates the transformation and generation of disinfection byproducts (DBPs) during chlorination treatment, which is essential for effective water quality evaluation and chlorination optimization. This study used fluoxetine (FLX) and humic acid (HA) as representative substances to analyze changes in their chemical characteristics and zebrafish embryonic developmental toxicity under different chlorination conditions. The analysis of the fluorescence characteristics and Fourier transform ion cyclotron resonance mass spectrometry indicated that chlorination treatment increased the aromatic compound content of the HA solution. FLX addition further increased the presence of aromatic ring structures and oxidized molecules, resulting in the formation of numerous Cl-DBPs with highly unsaturated and phenolic structures. Moreover, different responses in zebrafish embryo development and behavior were found with FLX, HA, and FLX + HA exposures. Cardiotoxicity was linked to changes in the concentration of cTn-I protein and expression of various genes. Prolonged chlorination conditions showed higher toxicities. Correlation analysis found a weak relation between chemical indicators and toxicity data, indicating that both analysis methods need to be considered when analyzing the impact of the chlorination. Further, a combination of chemical analyses and toxicity tests revealed that the FLX + HA solution with chlorination conditions of 3 mg/L for 30 min had lower chemical and toxic effects in this experiment. This study provides valuable scientific insights for the safe discharge of chlorinated water containing FLX and dissolved organic matter, as well as guidance for optimizing chlorination parameters in wastewater treatment.

Effects of land reclamation on peatland carbon stability in Sanjiang Plain (Northeast China) over the last century

Peatlands store vast amounts of soil carbon and the stability of this carbon pool plays a crucial role in the carbon dynamics under global change. In the Sanjiang Plain, one of the important peatlands distributed region in China, peatlands were seriously affected by the regional land reclamation during the last century. While, there is a scarcity of data evaluating the impact of land reclamation on peatland carbon stability. Here, based on 210Pb dating of the Shenjiadian (SJD) peatland, we reconstructed historical variations in peatland carbon stability and assessed its response on regional land reclamation over the last century in the Sanjiang Plain. The results showed that the highest aromatic content (25.2 ± 0.7 %) and the lowest carbohydrate content (34.7 ± 2.5 %) occurred between 1950 and 1980, coinciding with the period of extensive second land reclamation in the Sanjiang Plain. The increase in regional human activities led to greater accumulation of pyrogenic carbon in the peatland, enhancing carbon stability in the 1950 s. However, as farmland area continued to grow in the 1960 s, local fires caused by agricultural activities led to more frequent peat fires, promoting the accumulation of herbaceous litter in the peatland, which decreased the stability of the peatland carbon pool but increased carbon accumulation rates. With the proportion of shrub litter increasing and regional land reclamation weakening after 1980, the accumulation of shrub litters has increased both carbon stability and carbon accumulation rates in the studied peatland, particularly after 2000.

Interpreting the removal behaviours of aniline and 3,4-diaminotoluene on aromatic carbon-rich magnetic polymer: Statistical modelling, DFT quantitative calculations and new perspectives

The widespread presence of harmful and stubborn amine organic contaminants in aquatic environments motivated the exploration of efficient technologies for alleviating their serious environmental crisis. Herein, the recyclable magnetic Schiff base polymer (Fe3O4-TENE) with satisfactory and promising capacity in treating aniline and 3,4-diaminotoluene as representative amine organic contaminants was fabricated via a simple in-situ polymerization method, which combined the magnetic separability advantage of magnetic oxides with the abundant aromatic carbon content properties of Schiff base polymer. Multiple characterization methods verified the effectiveness of the in-situ polycondensation coating reaction and analyzed the physicochemical properties of Fe3O4-TENE. The Fe3O4-TENE possessed abundant homogeneous reaction sites and excellent regeneration performance, multiple diffusion driving forces and micro-mechanisms co-participated in the removal reaction. The adsorption pathway, underlying reaction mechanism and the most probable bonding system were identified based on the statistical modelling and DFT quantitative calculations. Especially, the visible electrostatic potential molecular and molecular orbitals verified the π-π interaction and electrostatic forces greatly contributed to the removal reaction. The Driving forces – Challenges – Breakthrough – Application framework was proposed for comprehensively assessing the possible environmental application of Fe3O4-TENE. Overall, this work not only provides important insights into the utilization of magnetic polymer composite to alleviate ecological and environmental risks caused by amine organic pollutants, but also contributes to an in-depth excavation of the bonding types and removal mechanisms from both micro and macro perspectives.

Predicting Petroleum SARA Composition from Density, Sulfur Content, Flash Point, and Simulated Distillation Data Using Regression and Artificial Neural Network Techniques

The saturate, aromatic, resin, and asphaltene content in petroleum (SARA composition) provides valuable information about the chemical nature of oils, oil compatibility, colloidal stability, fouling potential, and other important aspects in petroleum chemistry and processing. For that reason, SARA composition data are important for petroleum engineering research and practice. Unfortunately, the results of SARA composition measurements reported by diverse laboratories are frequently very dissimilar and the development of a method to assign SARA composition from oil bulk properties is a question that deserves attention. Petroleum fluids with great variability of SARA composition were employed in this study to model their SARA fraction contents from their density, flash point, sulfur content, and simulated distillation characteristics. Three data mining techniques: intercriteria analysis, regression, and artificial neural networks (ANNs) were applied. It was found that the ANN models predicted with higher accuracy the contents of resins and asphaltenes, whereas the non-linear regression model predicted most accurately the saturate fraction content but with an accuracy that was lower than that reported in the literature regarding uncertainty of measurement. The aromatic content was poorly predicted by all investigated techniques, although the prediction of aromatic content was within the uncertainty of measurement. The performed study suggests that as well as the investigated properties, additional characteristics need to be explored to account for complex petroleum chemistry in order to improve the accuracy of SARA composition prognosis.

Solute structure effect on polycyclic aromatics separation from fuel oil: Molecular mechanism and experimental insights

AbstractIonic liquids (ILs) are promising solvents for separating aromatics from fuel oils. However, studies for separate polycyclic aromatics with ILs are rare and insufficient, and the impact of solute structure on extraction performance still needs to be determined. In this work, we use 1‐ethyl‐3‐methylimidazolium bis([trifluoromethyl]sulfonyl)imide ([EMIM][NTF2]) as an extractant to separate 1‐methylnaphthalene, quinoline, and benzothiophene from dodecane mixtures. Liquid–liquid equilibrium experiments identified the optimal operating conditions. Nine solute molecules, including five alkanes and four aromatic hydrocarbons, were used to study the relationship between extraction performance and solute structure. Molecular dynamics simulation and quantum chemistry calculations gave a deep insight and reasonable interpretation of the structure‐performance relationship at the molecular level. An industrial‐scale extraction process was proposed. The IL can be easily regenerated using heptane as a back‐extractive solvent. A high‐purity fuel oil with aromatic content below 0.5 wt% is obtained after 8‐stage extraction.

Examination of primary aromatic amines content in polylactic acid straws and migration into food simulants using SERS with LC-MS

Polylactic acid (PLA) straws hold eco-friendly potential; however, residual diisocyanates used to enhance the mechanical strength can generate carcinogenic primary aromatic amines (PAAs), posing health risks. Herein, we present a rapid, comprehensive strategy to detecting PAAs in 18 brands of food-grade PLA straws and assessing their migration into diverse food simulants. Surface-enhanced Raman spectroscopy was conducted to rapidly screen straws for PAAs. Subsequently, qualitative determination of migrating PAAs into various food simulants (4 % acetic acid, 10 % ethanol, 50 % ethanol) occurred at 70 °C for 2 h using liquid chromatography-mass spectrometry. Three PAAs including 4,4′-methylenedianiline, 2,4′-methylenedianiline, and 2,4-diaminotoluene were detected in all straws. Specifically, 2,4-diaminotoluene in 50 % ethanol exceeded specific migration limit of 2 μg/kg, raising safety concerns. Notably, PAAs migration to 10 % and 50 % ethanol surpassed that to 4 % acetic acid within a short 2-hour period. Moreover, PLA straws underwent varying degrees of shape changes before and after migration. Straws with poly(butylene succinate) resisted deformation compared to those without, indicating enhanced heat resistance, while poly(butyleneadipate-co-terephthalate) improved hydrolysis resistance. Importantly, swelling study unveiled swelling effect wasn’t the primary factor contributing to the increased PAAs migration in ethanol food simulant, as there was no significant disparity in swelling degrees across different food simulants. FT-IR and DSC analysis revealed higher PAAs content in 50 % ethanol were due to highly concentrated polar ethanol disrupting hydrogen bonds and van der Waal forces holding PLA molecules together. Overall, minimizing contact between PLA straws and alcoholic foods is crucial to avoid potential safety risks posed by PAAs.