Structure Of Hydrocarbons Research Articles

Catalytic cracking of castor oil via microwave assisted method

Castor oil extracted from seeds of Ricinus Communis plant has an immense potential being used to yield valuable hydrocarbons with shorter chain length. Castor oil contains chemical structures of heavy hydrocarbons and long chains may undergo a cracking process which are similar to that as in petrochemical industries. However, cracking process requires extremely high temperature and energy input. This research came by with an attempt to reduce waste of energy using both microwave assisted method and modified metal catalyst, Zn/ZSM-5 to provide sufficient energy for cracking process to occur at comparatively low temperature. Wet impregnation method was used for Zn/ZSM-5 catalyst preparation and the experiments were carried out via microwave-assisted method. The microwave effect on the temperature and mass of condensate formed was investigated at three different output powers; 650, 700 and 750 W, under different Zn/ZSM-5 concentrations; 5, 8 and 10 wt% for 1 h. Results showed that cracking of castor oil is feasible at low temperature (<250 °C) using modified Zn/ZSM-5 via microwave assisted method. The highest yield of total mass of condensate (5.61%) was obtained from 750 W output power and 10 wt% Zn/ZSM-5 catalyst concentration. In addition, the highest cracking percentage (97.7%) was obtained from 750 W output power and 5 wt% Zn/ZSM-5 catalyst concentration. Valuable cracked compounds such as octane for fuel products and undecylenic acid for pharmaceutical uses were obtained.

Synthesis and properties of novel bis-chalcone-based photoinitiators for LED polymerization with photobleaching and low migration

In this work, six bis-chalcone-based photoinitiators (1E,4E)-1,5-diphenylpenta-1,4-dien-3-one (DKE-1), (1E,4E)-1,5-di(naphthalen-2-yl) penta-1,4-dien-3-one (DKE-2), (1E,4E)-1,5-di(anthracen-9-yl)penta-1,4-dien-3-one (DKE-3), (1E,4E)-1,5-di(pyren-1-yl)penta-1,4-dien-3-one (DKE-4), (1E,3E,6E,8E)-1,9-diphenylnona-1,3,6,8-tetraen-5-one (DKE-5) and (3E,6E)-1,9-diphenylnona-3,6-dien-1,8-diyn-5-one (DKE-6) were synthesized by Claisen-Schmidt reaction. The influence of different polycyclic aromatic hydrocarbon structures and unsaturated groups on the maximum absorption wavelength, solubility and migration properties of DKEs was studied. It was found that with the increase of the number of benzene rings for DKE-1 to DKE-4 and the introduction of CC, CC bonds for DKE-5-DKE-6 in the molecular structure, the absorption wavelength gradually red-shifted to the visible region, the maximum absorption wavelength of DKE-4 and DKE-6 was 442 nm, 395 nm respectively. Besides, DKE-5 and DKE-6 can effectively solve the problem of poor solubility. Three-component photoinitiating system of DKEs/iodonium/amine presented efficiently photopolymerization and the double bond conversion can reach >80 %. DKEs have shown certain photobleaching properties, indicating that it can be used for deep curing of coatings. In addition, DKEs have low migration, the migration ratio of DKE-4 was low to 0.7 %.

Double-bond equivalence linear equations for structural interpretation of fossil hydrocarbons

The structural elucidation of hydrocarbons still remains a challenge for petroleomics characterization using ultrahigh-resolution mass spectrometry (UHRMS). Double-bond equivalence (DBE) linear equations were proposed for better predicting and understanding the molecular structure of hydrocarbons in crude oils. They were defined as the linear equation in the Cartesian coordinate system with carbon number as the abscissa and DBE as the ordinate, where y-intercepts represented the starting core structures and slopes described the structural increments. According to the magnitude of the slope determined by ΔDBE/ΔC (carbon number), DBE linear equations were divided into three types: alkyl homologous equation, naphthenic homologous equation, and aromatic homologous equation. Any structure of fossil hydrocarbons can be represented by the combination of these three types of equations, as all typical types of structural increments and their adding modes were considered. Furthermore, a distribution map of aromatic hydrocarbons was constructed based on DBE linear equations, which could provide an intuitionistic illustration of the ring structures, especially the aromatic structures of fossil hydrocarbons. The feasibilities of the distribution map to distinguish naphthenic and aromatic rings and to classify the numbers of aromatic rings were verified by experimental results obtained by on-line coupling of normal phase liquid chromatography and ultrahigh-resolution mass spectrometry. In real sample analysis, combination of DBE linear equations and tandem MS was demonstrated to be a superior way for structural elucidation, because DBE linear equations could provide a confined database for effective structural search.

Effect of Branching on Mutual Solubility of Alkane–CO2 Systems by Molecular Simulations

Mutual solubilities of hydrocarbon-CO2 systems are important in a broad range of applications. Experimental data and theoretical understanding of phase behavior of large hydrocarbon molecules and CO2 are limited. This is especially true in relation to the molecular structure of hydrocarbons when the carbon number exceeds 12. In this work, the continuous fractional component Gibbs ensemble Monte Carlo simulations are used to investigate mutual solubility of different alkane and CO2 systems and the molecular structure. We investigate the mutual solubility of n-decane, n-hexadecane, n-eicosane, and the corresponding structural isomers in the CO2-rich and hydrocarbon-rich phase. The focus will be solubility of the heavy normal alkanes and their structural isomers in CO2. The simulation results are verified by comparing the experimental data when measurements are available. The simulation of phase behavior of the n-decane-CO2 system agrees with the experiments. We also present simulation results of n-hexadecane-CO2 and n-eicosane-CO2 systems away from the critical region partly due to the finite size effect. We establish that solubility of the hydrocarbons in CO2 is improved by change of the molecular structure in heavier alkanes. The enhanced solubility is limited in decane isomers, but the isomers of hexadecane and eicosane show 2- to 3-time solubility enhancement. The molecular dynamics simulations suggest that the improvement is from a higher coordination number of CO2 for methyl (CH3) rather than for methylene (CH2) groups. This study sets the stage for molecular engineering and synthesis of hydrocarbons that are soluble in CO2 not only by considering functionality but also by changing the molecular structure. The solubility enhancement is the first step in viscosification of CO2 which broadens the use of CO2.

Evaluation of the Use of Lime and Nanosilica for the Improvement of Clay Soil Structure and Degradation of Hydrocarbons

Soil structure is an important key in the bioremediation process; for instance, clay soils tend to have high absorption of pollutants and low rates of bioremediation due to their high plasticity and oxygen restrictions. This work assesses seven different treatments for contaminated clay soil using lime, silica nanoparticles, and both components in combination. After a three-month treatment, the variation of the soil granulometry, pH, porosity, cation exchange capacity (CEC), humidity, organic matter, respirometry, and humic acids were measured in order to evaluate the improvements regarding soil structure. Furthermore, total petroleum hydrocarbon (TPH), polycyclic aromatic hydrocarbons (PAHs) and heavy metals were monitored before and after the treatments. The combined treatment using lime and nanosilica presented the best results, reducing the percentage of clays from 61% to 5% and showing a relationship between improved of soil structure and the reduction of pollutants, with a 35% removal for TPHs being the highest obtained with the seven treatments.

Solubility of gaseous hydrocarbons in ionic liquids using equations of state and machine learning approaches

Ionic liquids (ILs) have emerged as suitable options for gas storage applications over the past decade. Consequently, accurate prediction of gas solubility in ILs is crucial for their application in the industry. In this study, four intelligent techniques including Extreme Learning Machine (ELM), Deep Belief Network (DBN), Multivariate Adaptive Regression Splines (MARS), and Boosting-Support Vector Regression (Boost-SVR) have been proposed to estimate the solubility of some gaseous hydrocarbons in ILs based on two distinct methods. In the first method, the thermodynamic properties of hydrocarbons and ILs were used as input parameters, while in the second method, the chemical structure of ILs and hydrocarbons along with temperature and pressure were used. The results show that in the first method, the DBN model with root mean square error (RMSE) and coefficient of determination (R2) values of 0.0054 and 0.9961, respectively, and in the second method, the DBN model with RMSE and R2 values of 0.0065 and 0.9943, respectively, have the most accurate predictions. To evaluate the performance of intelligent models, the obtained results were compared with previous studies and equations of the state including Peng–Robinson (PR), Soave–Redlich–Kwong (SRK), Redlich–Kwong (RK), and Zudkevitch–Joffe (ZJ). Findings show that intelligent models have high accuracy compared to equations of state. Finally, the investigation of the effect of different factors such as alkyl chain length, type of anion and cation, pressure, temperature, and type of hydrocarbon on the solubility of gaseous hydrocarbons in ILs shows that pressure and temperature have a direct and inverse effect on increasing the solubility of gaseous hydrocarbons in ILs, respectively. Also, the evaluation of the effect of hydrocarbon type shows that increasing the molecular weight of hydrocarbons increases the solubility of gaseous hydrocarbons in ILs.

Application of the Y-Rule and Theoretical Study to Understand the Topological and Electronic Structures of Polycyclic Aromatic Hydrocarbons from Atomic Force Microscopy Images of Soot, Coal Asphaltenes, and Petroleum Asphaltenes

Application of the Y-Rule and Theoretical Study to Understand the Topological and Electronic Structures of Polycyclic Aromatic Hydrocarbons from Atomic Force Microscopy Images of Soot, Coal Asphaltenes, and Petroleum Asphaltenes

Stability Study of the Irradiated Poly(lactic acid)/Styrene Isoprene Styrene Reinforced with Silica Nanoparticles.

In this paper, the stability improvement of poly(lactic acid) (PLA)/styrene-isoprene block copolymer (SIS) loaded with silica nanoparticles is characterized. The protection efficiency in the material of thermal stability is mainly studied by means of high accurate isothermal and nonisothermal chemiluminescence procedures. The oxidation induction times obtained in the isothermal CL determinations increase from 45 min to 312 min as the polymer is free of silica or the filler loading is about 10%, respectively. The nonisothermal measurements reveal the values of onset oxidation temperatures with about 15% when the concentration of SiO2 particles is enhanced from none to 10%. The curing assay and Charlesby–Pinner representation as well as the modifications that occurred in the FTIR carbonyl band at 1745 cm−1 are appropriate proofs for the delay of oxidation in hybrid samples. The improved efficiency of silica during the accelerated degradation of PLA/SIS 30/n-SiO2 composites is demonstrated by means of the increased values of activation energy in correlation with the augmentation of silica loading. While the pristine material is modified by the addition of 10% silica nanoparticles, the activation energy grows from 55 kJ mol−1 to 74 kJ mol−1 for nonirradiated samples and from 47 kJ mol−1 to 76 kJ mol−1 for γ-processed material at 25 kGy. The stabilizer features are associated with silica nanoparticles due to the protection of fragments generated by the scission of hydrocarbon structure of SIS, the minor component, whose degradation fragments are early converted into hydroperoxides rather than influencing depolymerization in the PLA phase. The reduction of the transmission values concerning the growing reinforcement is evidence of the capacity of SiO2 to minimize the changes in polymers subjected to high energy sterilization. The silica loading of 10 wt% may be considered a proper solution for attaining an extended lifespan under the accelerated degradation caused by the intense transfer of energy, such as radiation processing on the polymer hybrid.

Microwave-assisted synthesis of trimethylolpropane triester (bio-lubricant) from camelina oil

Vegetable oils, whose hydrocarbon structure is very similar to that of petroleum products, are ideal renewable and sustainable alternatives to petroleum lubricants. Bio-lubricants are commonly synthesized by modifying the chemical structure of vegetable oils. In this study, microwave irradiation was applied to intensify the mass-transfer-limited transesterification reaction to produce trimethylolpropane triester (bio-lubricant) from camelina oil as a promising local energy crop. A rotatable RSM-BBD method was applied to find the optimal levels of experimental factors, namely reaction time (67.8 min), the catalyst concentration (1.4 wt%) and the molar ratio (3.5). In these optimal levels, the reaction yield of 94.3% was obtained with desirability of 0.975. The quadratic statistical model with a determination coefficient of 97.97%, a standard deviation of 0.91 and a variation coefficient of 1% was suggested as the most appropriate model by Design-Expert software. Finally, the physicochemical properties of the purified product were in accordance with the requirements of the ISO-VG22 base oil standard.

BoCAPS: Rapid screening of chemical races in Botryococcus braunii with direct PCR-CAPS

The colony-forming microalga Botryococcus braunii produces petroleum-like hydrocarbons and is a promising source for biofuel production. B. braunii is classified into three chemical races (A, B, L) plus a tentative class (S), based on the structure of its hydrocarbons. The determination of hydrocarbon structure in a newly isolated strain requires several months for culturing and analysis. As potential for biofuel production differs among races, a rapid method for estimating race is needed for the effective bioprospecting. This study aimed to develop a DNA-based rapid estimation method (BoCAPS) of the chemical races of B. braunii and to test the feasibility of direct PCR from a single colony. A total of 247 wild strains were isolated from 29 ponds in Japan and Indonesia, their 18S rRNA sequences determined, and a phylogenetic tree constructed based on the sequences of standard strains with known chemical races. Polymorphisms between clades of the phylogenetic tree corresponding to chemical races were mapped, and a cleaved amplified polymorphic sequence (CAPS) marker was developed for race discrimination. Direct PCR was tested on a single colony as a template. We demonstrated that HaeIII restriction of the PCR product enables race discrimination on agarose gels, and that direct PCR amplifies the 18S rRNA gene from a single colony without any pre-treatment. With BoCAPS, we investigated race compositions of the isolated strains and determined that the B-race was dominant (74 %). Neither the A-race nor S-race strains were isolated from tropical regions. In addition, we observed a few ponds in which minor races (L or A) were dominant and some ponds with a mixture of different races. The BoCAPS allows us to estimate chemical race without the time-consuming and expensive analysis of hydrocarbons and will be useful for high-throughput screening and ecological studies of wild populations.

EFFECT OF CATALYST PROPERTIES ON THE DEOXYGENATION REACTION OF VEGETABLE OIL AND MODEL COMPOUND TO PRODUCE DIESEL RANGE HYDROCARBON FUELS: A REVIEW

The concern associated with the depletion of fossil fuel energy has opened up windows of opportunity for researchers to develop potential energy from renewable resources. The renewable green diesel with diesel range hydrocarbon structure has gained increasing popularity by removing oxygen molecule via direct or hydrodeoxygenation (HDO) and indirect or deoxygenation (DO) reaction. The catalyst design is an important key to achieve the high quality of diesel range hydrocarbon fuels. The different catalyst properties effect to the distribution of deoxygenated liquid product, the catalytic activity and coke formation during the reaction process. The interaction between metal and support catalyst causes electron transfer to give the synestistic effect. The acidity and basicity play important role in C-C and C-O breaking bond in triglyceride and prevent the coke formation. The pore structure and pore size catalyst provide the accessibility of active sites alleviates the diffusion limitation of reactants/ products.

Influence of asphalt-derived volatiles on property of the biochar from pyrolysis of sawdust

Inorganics are an important fraction of coal and they could involve the in co-pyrolysis of biomass and coal. In this study, to exclude interference of inorganics of coal and focus on exclusively the potential interaction of the volatiles from coal with that from biomass, the co-pyrolysis of asphalt and sawdust was conducted. The hydrocarbon radicals from asphalt could interact with the sawdust derived volatiles, diminishing the production of phenolics, aldehydes, ketones, etc. In addition, the hydrocarbon radicals themselves could deposit on the surface of the biochar and also reacted with the oxygen-containing organics, which increased the overall yield of biochar and promoted both the deoxygenation and carbonization reactions. This made the biochar from the co-pyrolysis carbon-rich and thermally more stable, which also enhanced the transition of amorphous carbon to graphite carbon on the surface of the biochar. In addition, the in-situ Diffuse Reflection Infrared Fourier Transform Spectra (DRIFTS) characterization indicated that the biochar from the co-pyrolysis at 450 °C featured with abundant aliphatic and aromatic hydrocarbon structures, while that from single sawdust pyrolysis consisted of abundant oxygen-containing functionalities such as ether bridge bonds, carbonyl, and carboxyl groups with low thermal stabilities.

Neutrophil Immunomodulatory Activity of Farnesene, a Component of Artemisia dracunculus Essential Oils.

Despite their reported therapeutic properties, not much is known about the immunomodulatory activity of essential oils present in Artemisia species. We isolated essential oils from the flowers and leaves of five Artemisia species: A. tridentata, A. ludoviciana, A. dracunculus, A. frigida, and A. cana. The chemical composition of the Artemisia essential oil samples had similarities and differences as compared to those previously reported in the literature. The main components of essential oils obtained from A. tridentata, A. ludoviciana, A. frigida, and A. cana were camphor (23.0–51.3%), 1,8-cineole (5.7–30.0%), camphene (1.6–7.7%), borneol (2.3–14.6%), artemisiole (1.2–7.5%), terpinen-4-ol (2.0–6.9%), α-pinene (0.8–3.9%), and santolinatriene (0.7–3.5%). Essential oils from A. dracunculus were enriched in methyl chavicol (38.8–42.9%), methyl eugenol (26.1–26.4%), terpinolene (5.5–8.8%), (E/Z)-β-ocimene (7.3–16.0%), β-phellandrene (1.3–2.2%), p-cymen-8-ol (0.9–2.3%), and xanthoxylin (1.2–2.2%). A comparison across species also demonstrated that some compounds were present in only one Artemisia species. Although Artemisia essential oils were weak activators of human neutrophils, they were relatively more potent in inhibiting subsequent neutrophil Ca2+ mobilization with N-formyl peptide receptor 1 (FPR1) agonist fMLF- and FPR2 agonist WKYMVM, with the most potent being essential oils from A. dracunculus. Further analysis of unique compounds found in A. dracunculus showed that farnesene, a compound with a similar hydrocarbon structure as lipoxin A4, inhibited Ca2+ influx induced in human neutrophils by fMLF (IC50 = 1.2 μM), WKYMVM (IC50 = 1.4 μM), or interleukin 8 (IC50 = 2.6 μM). Pretreatment with A. dracunculus essential oils and farnesene also inhibited human neutrophil chemotaxis induced by fMLF, suggesting these treatments down-regulated human neutrophil responses to inflammatory chemoattractants. Thus, our studies have identified farnesene as a potential anti-inflammatory modulator of human neutrophils.

Petroleum potential of Jurassic regional reservoirs in the Yenisei-Khatanga and adjacent Gydan petroleum-bearing areas

The paper discusses methods and results of the petroleum potential quantification in regional Jurassic reservoirs within the Yenisei-Khatanga petroleum-bearing area (PBA) and eastern Gydan PBA. The structure and distributions of initial in-place hydrocarbons in reservoirs, petroleum-bearing regions, and by categories of reserves and resources are presented. The petroleum potential was assessed by a geological method from specific densities of HC reserves per unit area, on the basis of comprehensive analysis of tectonic, lithologic-facies and geochemical criteria for determination of petroleum potential. According to the author's estimates, the prognosed initial hydrocarbon resources in Jurassic reservoirs within the Yenisei-Khatanga and eastern Gydan PBR amount to 12505 million tons total hydrocarbon equivalent, which includes 10935 billion m (87.5%) gas, and 1570 million tons (12.5%) condensate.

Predicting Primary Biodegradation of Petroleum Hydrocarbons in Aquatic Systems: Integrating System and Molecular Structure Parameters using a Novel Machine-Learning Framework.

Quantitative structure–property relationship (QSPR) models for predicting primary biodegradation of petroleum hydrocarbons have been previously developed. These models use experimental data generated under widely varied conditions, the effects of which are not captured adequately within model formalisms. As a result, they exhibit variable predictive performance and are unable to incorporate the role of study design and test conditions on the assessment of environmental persistence. To address these limitations, a novel machine‐learning System‐Integrated Model (HC‐BioSIM) is presented, which integrates chemical structure and test system variability, leading to improved prediction of primary disappearance time (DT50) values for petroleum hydrocarbons in fresh and marine water. An expanded, highly curated database of 728 experimental DT50 values (181 unique hydrocarbon structures compiled from 13 primary sources) was used to develop and validate a supervised model tree machine‐learning model. Using relatively few parameters (6 system and 25 structural parameters), the model demonstrated significant improvement in predictive performance (root mean square error = 0.26, R 2 = 0.67) over existing QSPR models. The model also demonstrated improved accuracy of persistence (P) categorization (i.e., “Not P/P/vP”), with an accuracy of 96.8%, and false‐positive and ‐negative categorization rates of 0.4% and 2.7%, respectively. This significant improvement in DT50 prediction, and subsequent persistence categorization, validates the need for models that integrate experimental design and environmental system parameters into biodegradation and persistence assessment. Environ Toxicol Chem 2022;41:1359–1369. © 2022 ExxonMobil Biomedical Sciences, Inc. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Simple Double Hetero[5]helicenes Realize Highly Efficient and Narrowband Circularly Polarized Organic Light-Emitting Diodes

Simple Double Hetero[5]helicenes Realize Highly Efficient and Narrowband Circularly Polarized Organic Light-Emitting Diodes

Syntheses of Anthracene-Centered Large PAH Diimides and Conjugated Polymers.

Polycyclic aromatic hydrocarbon (PAH) structures with suitable electron-withdrawing groups are useful building blocks for developing optical and electron-transporting materials. Here, we report the application of a double benzannulation process to the syntheses of PAH diimides with enlarged π-frameworks featuring a central anthracene moiety. The preparations are realized by copper-catalyzed [4+2] cycloaddition of ethynyl-substituted aromatic dicarboximide to 2,5-bis(phenylethynyl)terephthalaldehyde, followed by intramolecular photocyclization or direct arylation via Heck cross coupling. A central symmetric benzo[1,2-k:4,5-k']-bis(fluoranthene)-3,4,12,13-tetracarboxyl diimide (BFDI) is acquired, with the single crystal structure revealing its completely planar polycyclic skeleton. Such a shape-persistent PAH expectedly exhibits a tendency to stack face-to-face and forms J-aggregates. Moreover, BFDI can be difunctionalized site-selectively at the reactive 9 and 10 positions of the anthracene unit and then applied to prepare conjugated polymers. When coupled with 1,4-diketopyrrolo[3,4-c]-pyrrole (DPP) via thiophene and dithiophene linkers, two polymers with significantly broadened absorption bands extended to the near-infrared regime are obtained, evidencing the effective π-conjugative extension ability of BFDI unit.

Facile synthesis of M2(m‐dobdc) (M = Fe and Mn) metal‐organic frameworks for remarkable hydrogen storage

AbstractMetal‐organic frameworks (MOFs) are emerging as promising candidates for hydrogen storage material because of their porosity and adjustable hydrocarbon structures coordinated with the metal element. Present work explore the synthesis of M2(m‐dobdc) (M = Fe and Mn; m‐dobdc4− = 4,6‐dioxido‐1,3‐benzenedicarboxylate) metal‐organic frameworks via solvothermal method for the purpose of hydrogen storage application. The X‐ray diffraction, transmission electron microscope, scanning electron microscope, energy dispersive X‐ray analysis, and nuclear magnetic resonance spectroscopic studies have been done to ensure the synthesized material is M2(m‐dobdc) (M = Fe and Mn) MOFs. The Brunauer‐Emmett‐Teller (BET) analysis reveals the average pore size of 36.271 nm for Mn2(m‐dobdc) MOF whereas the average pore size for fe2(m‐dobdc) MOF was found to be 2.1992 nm. The as‐prepared MOF samples are in the mesoporous range based on pore size distribution (internal pore diameter greater than 2 nm) with spherical pore geometry. Hydrogen storage studies shows that Fe2(m‐dobdc) has a hydrogen storage capacity of 0.18 wt% at ambient temperature (30°C) under 100 atm H2 pressure, whereas the hydrogen storage capacity for Mn2(m‐dobdc) is 1.38 wt% under identical conditions of temperature and pressure. The hydrogen storage capacity at liquid nitrogen temperature (−196°C) under 100 atm H2 pressure for Fe2(m‐dobdc) and Mn2(m‐dobdc) is 4.31 and 8.21 wt%, respectively.

Aza-Triangulene: On-Surface Synthesis and Electronic and Magnetic Properties.

Nitrogen heteroatom doping into a triangulene molecule allows tuning its magnetic state. However, the synthesis of the nitrogen-doped triangulene (aza-triangulene) has been challenging. Herein, we report the successful synthesis of aza-triangulene on the Au(111) and Ag(111) surfaces, along with their characterizations by scanning tunneling microscopy and spectroscopy in combination with density functional theory (DFT) calculations. Aza-triangulenes were obtained by reducing ketone-substituted precursors. Exposure to atomic hydrogen followed by thermal annealing and, when necessary, manipulations with the scanning probe afforded the target product. We demonstrate that on Au(111), aza-triangulene donates an electron to the substrate and exhibits an open-shell triplet ground state. This is derived from the different Kondo resonances of the final aza-triangulene product and a series of intermediates on Au(111). Experimentally mapped molecular orbitals match with DFT-calculated counterparts for a positively charged aza-triangulene. In contrast, aza-triangulene on Ag(111) receives an extra electron from the substrate and displays a closed-shell character. Our study reveals the electronic properties of aza-triangulene on different metal surfaces and offers an approach for the fabrication of new hydrocarbon structures, including reactive open-shell molecules.

COMPARATIVE ANALYSIS OF THE FLOW STRUCTURE OF POLAR SOLVENT AND UNREFINED HYDROCARBON FLOWING IN A CYLINDRICAL BIFURCATED CHANNEL

Objective: The effect of geometric bifurcated system on flow of fluid may be greatly influenced by the angle of bifurcation or the density, capillary action etc. and other physical properties of the fluid. The aim of this work is to carry out a comparative analysis of the flow structure of polar solvent and unrefined hydrocarbons in a cylindrical bifurcated channel.&#x0D; Materials and Methods: An experimental method was used to study the flow structure of water and crude oil, representing polar solvent and unrefined hydrocarbon respectively flowing through a bifurcated channel, with angles of bifurcation ranging from 10o, 20o, 30o, 40o, 50o and 60o, corresponding to 5o, 10o, 15o, 20o, 25o and 30o measured from the centerline of the main channel. The fluid samples were allowed to flow through the bifurcated channels and the time taken to recover 100ml, 200ml, 300ml 400ml and 500ml in a beaker is recorded. The bifurcated angle is resolved into vertical and horizontal components and the total length for both components obtained, as the flow velocity is computed for both lengths and the results presented.&#x0D; Results: The profile of resulted shows that for polar solvents such as water, the velocity gradient increases as the vertical distance increases and horizontal distance decrease correspondingly due to increasing bifurcation angle, as a similar trend is also observed for crude oil.&#x0D; Conclusion: For both samples representing their respective class of fluid, the result further shows the existence of velocity difference at opposite walls of the bifurcated daughter channels. The wall at higher velocity is usually the site where the skin friction that changes the flow from laminar to turbulent is created. The experimental result confirmed the effects of bifurcation on flow stability to significant in a more viscous fluid.&#x0D; Recommendation: Fluid samples with different physical properties should be investigated using this experimental technic, and the impact of two-stage bifurcated system can also be investigated to ascertain the degree of stability offer by the geometric bifurcated network system.