A new database predicted with theoretical chemistry of organometallic star-like compounds with a central planar carbon atom, named Star-Database, is presented. Planar star-like structures with D-3h, D-4h, and D-5h symmetries are considered, where the central carbon atom is three-, tetra-, or penta-coordinated in a single plane. Combinations of atoms ranging from hydrogen to bismuth (excluding noble gases, lanthanides, and actinides) were considered along with charges of +1, 0, and -1. The systems have been generated through a systematic geometric and energetic screening, employing a multistep optimization and filtering protocol based on density functional theory (DFT), DFT-D3, and M & oslash;ller-Plesset (MP2 and MP4) methods. All the molecules in the Star-Database satisfy three geometrical criteria: (a) planarity, (b) star-like geometry (the peripheral atoms arranged symmetrically around the central carbon resembling a star), and (c) coordination. There are 40-D-3h, 19-D-4h, and 10-D-5h star-like planar molecules in the Star-Database. The elemental abundance with symmetry is analyzed. The most abundant elements in the first coordination sphere are metals (Pd, Pt), and in the second coordination are nonmetals (Se, I) > Te > H > F, Cl. The Star-Database provides atomic coordinates, HOMO-LUMO energy gaps and orbitals, and XY-NICS maps of aromaticity. Only 19 star-molecules are potentially aromatic.

Asphaltenes play a major role in oil-water emulsion stability, aggregation, deposition, viscosity, and change of wettability to oil-wet; thus, a deep understanding of the interaction of an external magnetic field and asphaltenes is of utter importance to developing technologies friendly with the environment based on the application of magnetic fields to manage asphaltene-related issues in the oil industry. In spite of the studies reported in the literature of the effects of the magnetic field on crude oil and asphaltenes, the mechanisms in which the magnetic field interacts with asphaltenes are not completely understood. In the present contribution, the effect of an external magnetic field on the aggregation of three different asphaltenes (alpha-, beta-, and gamma-asphaltenes) extracted from light, medium, and heavy crude oils is studied experimentally and theoretically. The average chemical structures of the three asphaltenes and their structural isomers, which compose the polydispersity, are obtained through experimental analysis. Solutions in toluene (aromatic medium) of the three asphaltenes are placed under the effect of a constant external magnetic field of 0.1 T strength at a constant temperature of 30 degrees C, and the effect of the magnetic field on the aggregation of the asphaltene solutions is followed with fluorescence emission measurement at different times of magnetization for a total of 24 h. All of the fluorescence emission measurements under the magnetic field were performed in triplicate, and the error obtained is 1%. The magnetic field uniformity and stability were checked in each fluorescence emission measurement using a high-precision magnetic field meter. The analysis of the effect of the magnetic field on the aggregation is carried out by the rationalization of the average electronic density distribution in the polycyclic aromatic hydrocarbon (PAH) core of the asphaltenes and their structural topology using the Y-rule aromaticity, the percentage of electrons in pi-aromatic sextets, Y-rule mapping, and topological-structural parameters in the different asphaltenes. All the PAH average asphaltene structures were analyzed by their HOMO-LUMO energy gap, which falls within the reported experimental gap; the most predominant number of fused aromatic rings (nFAR); the pi-electronic distribution in resonant sextets (N R) obtained with the Y-rule aromaticity; the percentage of aromatic sextet (%N R); and Y-rule mapping (%N R/nFAR). It is found that the magnetic field strongly propitiates the aggregation of asphaltenes that contain a higher percentage of aromatic sextets, %N R = (total aromatic pi-sextet electron/total pi-electrons) x 100, in the distribution of the electronic density and a higher HOMO-LUMO energy gap. Density functional theory calculations of the magnetic susceptibility or magnetizability of the asphaltenes show that the physical origin of the magnetizability is the induced currents within the asphaltene molecules and that, under the effect of the external magnetic field, asphaltene molecules reorient with the smallest magnetizability component aligned antiparallel along the direction of the external magnetic field. The gamma-asphaltenes present the highest magnetic susceptibility (chi iso) and magnetic anisotropy (Delta chi an), but due to their large size (11FAR), it is more difficult for the gamma-asphaltenes' magnetic dipole to reorient. The reorientation of the asphaltenes position them face-to-face or displaced face-to-face; thus, facilitating their aggregation. The aggregation quenches the lambda 0-0 band in the fluorescence emission spectrum. This effect is more pronounced for the alpha-asphaltenes, which are less bulky and less heavy (9FAR). The beta-asphaltenes are the least magnetizable, the smallest (7FAR), and the ones with the smallest %N R. The heteroatoms in asphaltenes influence their behavior under magnetic fields by introducing lone pairs and partial localized charges that contribute to the magnetic susceptibility.

A novel structural unit is proposed for constructing crystalline materials and molecular systems by mimicking the morphologies of carbon in its sp2 allotropic forms. The new family of layered graphene-like crystals in 2D lattices exhibit crown ether-like cycles. The proposed structures are not limited to a single chemical element, carbon, and have the potential to modulate electronic properties based on their composition. Nine combinations of atomic elements of the structural unit are presented, which give rise to structures whose electronic gaps can vary from zero to 2.597 eV for a B-N-S-Si combination of the basic unit. Depending on the atomic composition, this structural unit may give rise to unstable or stable structures. The elastic constant analysis shows that three of the proposed structures are mechanically stable, while only the N-C-O-Ni configuration is both mechanically and dynamically stable, which is confirmed by the absence of negative frequencies in the dispersion calculations.

Graphene has been demonstrated as one of the most promising materials in many areas of high-tech enterprise. Here, we present a novel approach to graphene synthesis using solid-state carbon as a precursor and induction heating as an energy source. The basic physical principle has not changed, but the induction seems to be a driver for faster synthesis of graphene, opening new horizons for rapid synthesis. Copper is saturated by carbon during the heating stage, and then carbon diffuses by the conventional surface-mediated method that is enriched by a back-diffusion process during the cooling stage. The back-diffusion step promotes a rapid graphene synthesis of sheets covering the entire surface of the copper substrate. The carbon back-diffusion process occurs at higher temperatures (<800 degree celsius) and continues through temperatures as low as 400 degree celsius. Copper saturation with carbon occurs along the {111} planes, and its atom migration or precipitation occurs through the {110} and {100} planes via a back-diffusion mechanism. However, the actual synthesis of graphene occurs in the {111} plane, which is attributed to the epitaxial match with the {0001} planes in graphitic structures. The graphene sheets vary in thickness from single to multilayered, as verified by Raman and HRTEM.

The understanding of the molecular- and colloidal-structure of asphaltenes has seen a major progress; however, there are still issues that require answer. One of them is the location of the heteroatoms in the polycyclic aromatic hydrocarbon (PAH) fused aromatic ring (FAR) region of asphaltenes. Therefore, the effect on the frontier molecular orbitals (HOMO-LUMO) energy-gap due to the addition of a heteroatom (N or S) to PAHs, which are candidates of the PAH region in asphaltenes, has been systematically analyzed by placing S or N in various sites of the PAH molecule. The S is introduced as a thiophenic ring in a bay region, while the N is introduced as a pyridinic-N, which are prevalent forms in the asphaltene-PAH. 174 PAHs are studied with five fused aromatic rings (5FAR) to 10FAR. The π-electron allocation in resonant π-sextets and isolated double bonds is obtained using the Y-rule. The frontier orbitals optical transition is calculated with the ZINDO/S method. Within a FAR family an increment of π-sextets produces and increase of the HOMO-LUMO energy-gap. There is a linear relationship between the Y-rule mapping (percentage of fraction of π-sextet bond divided by nFAR) and the HOMO-LUMO energy-gap. In addition, the effect on the frontier orbitals energy-gap and on the π-electronic allocation due to the presence of N and S is negligible; therefore, to reach conclusions related to the asphaltene-PAH based on conclusions reached for PAH systems, with no heteroatoms, is a reasonable approach.

Biosurfactant production at reactor level by Serratia marcescens SmSA was optimized and evaluated to enhance the heavy oil recovery on carbonate rocks. Temperature, agitation, and carbon/nitrogen (C/N) ratio were evaluated to optimize biosurfactant production by using a Taguchi (L9) design. The best conditions (C/N ratio: 6, 25 degrees C, and agitation: 100 rpm) were used to scale up the biosurfactant production with a 3-L bioreactor. The best aeration for biosurfactant production was 0.66 volume of air per volume of liquid per minute (vvm), producing the lowest surface tension (26 mN/m) in 14 h, with a biosurfactant yield of 14.26 g/L as a crude product and 2.85 g/L as a purified product, and a critical micelle concentration of 280 mg/L. The biosurfactant was characterized as a lipopeptide, and it was stable under extreme conditions: pH (2-12), salinity up to 200 g/L, and temperature up to 150 degrees C confirmed by thermogravimetric analysis. Enhanced oil recovery test was carried out with a carbonate core and heavy oil under reservoir conditions, obtaining an additional recovery of 8%, due to reduced interfacial tension and modified wettability of the rock. These findings highlight the potential application of S. marcescens SmSA biosurfactant in enhanced oil recovery.

In this work, a series of novel random alkyl acrylic-amino alkyl acrylic bipolymers was synthetized by semi-continuous emulsion polymerization technique. The obtained bipolymers were characterized mainly by Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), 1D and 2D nuclear magnetic resonance (NMR) and size exclusion chromatography (SEC). Afterwards, these bipolymers were evaluated as demulsifying agents in four heavy crude oils. The evaluations revealed that the efficiency of the synthesized acrylic bipolymers to break the emulsion, induce the drop coalescence and clarify the remaining aqueous phase depends strongly on their alkyl acrylic/amino alkyl acrylic ratio in the chain and average molecular mass. Likewise, it could be noted in three samples of heavy crude oils from Motul field that a greater content of the amino alkyl acrylate monomer in the bipolymer chain and a higher molecular mass allowed reaching higher emulsion removal efficiencies, with good water clarification. It was also shown that, in all the cases, a single acrylic bipolymer is able to remove the water dispersed in petroleum in a more efficient way than a commercial formulation of four triblock bipolymers based on ethylene and propylene oxide, when it possesses convenient structural features. In addition, for a better understanding of the improved dehydrating efficiency of the new acrylic demulsifiers reported in this study, a mechanism of bridge formation between water drops to provoke coalescence was established by dissipative particle dynamics (DPD) simulation. This theoretical technique was also applied to calculate the decrease of the interfacial tension as a function of the number of alkyl acrylic-amino alkyl acrylic chains at the water/crude oil interface.

In this work, the helicenes are postulated as potential carriers of the diffuse interstellar bands, DIBs. The helicenes are nonplanar cata-condensed molecules structurally related to the polyacenes, and polyacenes have been already proposed as conceivable carriers of the DIBs. In here, the possible identity of the carrier of the DIB at 4502 angstrom is studied and potentially identified as a cata-condensed helicene using spectroscopic, statistical, and stability methods. First, statistic and spectroscopic information allow the fitting of the regression equation that governs the variation of the location of the published absorbance p-bands as a function of the number of fused aromatic rings (nFAR) for planar and helical cata-condensed polycyclic aromatic hydrocarbons with 1-14 FAR, and the application of this equation to establish the identity of the possible carrier of the 4502 angstrom DIB, that is, [26]helicene (C106H56). The difference between the calculated location of the p-band from the fitted equation and the DIB location under study is equal to 0.21%. Subsequently, an aromaticity argument demonstrates the presence of pi-delocalizing benzene effect in helicenes with the general formula C2+4NH2N+4, for example, [26]helicene, that would theoretically provide supplementary stability to the molecule to justify its occurrence. Finally, a feasible mechanism of formation of helicenes in the interstellar medium is proposed that involves successive additions of n-butane units to a phenanthrene moiety. To the best of our knowledge, this is the first report about the possible presence of cata-condensed helical molecules in the DIBs and the first study that theorizes that [26]helicene is the possible carrier of the DIB at 4502 angstrom.

The study and development of non-silicon-based defoamers for crude oils have been slightly investigated worldwide, despite urgent requirements of the petroleum industry. The suppression of crude oils has usually been resolved using commercial silicone defoamers (polysiloxanes), but these compounds cause serious problems such as catalyst poisoning in petroleum refining processes. In this study, an acrylic homopolymer series with different molecular structures was synthesized by emulsion polymerization, to determine the influence of the chemical repetitive unit on the defoaming capability. The following acrylic homopolymers were considered: poly(methyl acrylate) (PMA), poly(ethyl acrylate) (PEA), poly(hexyl acrylate) (PHA), poly(2-ethylhexyl acrylate) (PEHA), and poly(dodecyl acrylate) (PDA). These polyacrylates were evaluated as foam suppressors in heavy crude oil, by means of a static method based on the sudden pressure drop of the system, which has the advantage of mimicking the gas/crude oil conditions in a biphasic separation tank. PHA, PEHA, and PDA showed greater antifoaming activity than that of silicones to suppress crude oil foam but only at an appropriate weight-average molecular weight ((M) over bar (w)). The strong influence of the length of pendant groups in the repetitive unit, which constitutes polyacrylates, could be evidenced by this way. The defoaming activity of the series of acrylic homopolymers was correlated with two series of physicochemical parameters obtained by theoretical calculations using HyperChem software and by molecular dynamics simulations. A "pitching off" mechanism of bubble collapse could be clearly established by this last simulation method. These novel antifoaming agents, based on a variety of polyacrylates, are innocuous during crude oil refining, and their fabrication cost is economically competitive, so they can be applied in industrial separation tanks to eliminate petroleum foams.

The effect of the structure of oil asphaltenes and sodium naphthenates at the oil-water interface on the reduction of the oil-water interfacial tension and the formation of stable emulsions is investigated by dissipative particle dynamics (DPD). The coarse-grained model molecules at the mesoscale level are adopted instead of using atomistic models. DPD can process a much larger spatial and temporal scale system than molecular dynamics (MD) can. Two types of island asphaltene model structures are used in the calculations: one with O atoms and the other one without O atoms. A small sodium naphthenate (benzoic acid sodium salt) is included in the simulations. The interfacial tension (IFT) is evaluated at different concentrations of sodium naphthenate while maintaining the asphaltene concentration fixed to conclude on the stability of the emulsions formed. The IFT results obtained for both asphaltene models are compared to reach conclusions regarding the relationships between asphaltene structure, surface activity and coverage, orientation at the oil-water interface, and stability of the emulsion formed by the asphaltenes and sodium naphthenates. Initially, when there is no sodium napthenates in the systems but only asphaltenes, the IFT decreases from 45 mN/m to 40 mN/m, because of the presence of asphaltene molecules at the oil-water interface. With the addition of sodium naphthenates to the systems, it is found that the asphaltene with no O atoms in the structure is less oil-water interface active and it is required to add a concentration of 0.363 M of sodium naphthenate to lower the IFT from 40 mN/m to 35 mN/m. The reduction of the IFT is mainly due to the formation of a uniform film of sodium naphthenates that covers the oil-water interface and displaces most of the asphaltenes with no heteroatoms to the oil region. This would explain why only <2 wt % of the total content of asphaltenes in some oils is found in the material extracted from the oil-water interface. For the asphaltene with O atoms in the structure, only a concentration of 0.033 M of sodium naphthenate is required to lower the IFT from 40 mN/m to 35 mN/m, i.e., a 10 times less sodium naphthenate concentration is required to lower the interfacial tension. The asphaltene with O atoms in the structure is more oil-water interface active and forms stable emulsions with sodium naphthenates by creating a uniform film at the oil-water interface with the sodium naphthenates. Once the film is formed, the asphaltenes with oxygen in the structure do not desorb from the interface, in agreement with experimental observations. A detailed knowledge of the chemical structure of interfacial active asphaltenes and other interfacial materials such as naphthenates can help in the design of a new generation of demulsifiers to resolve water-in-oil emulsions problems in the oil industry.

In the present contribution, we have developed a database, called the FAR-database, where the acronym FAR stands for Fused Aromatic Rings, which presents the results of nuclear independent chemical shifts calculations, NICS(0), NICS(1), NICS(0)ZZ, and NICS(1)ZZ, of 660 neutral benzenoid-PAHs and cyclopenta-fused PAHs. The FAR-database provides NICS data of aromaticity of PAHs that could be used in data science and machine learning. To the best of our knowledge, no such database is available in the literature. The importance of this database lies in its potential to transform data into insight and knowledge. Additionally, a new visual representation of the NICS aromaticity pattern, based on the magnitude of the NICS value, is presented. Nowadays calculations of NICS(0)ZZ or NICS(1)ZZ have become popular methods to evaluate aromaticity of systems. By looking at all the 660 systems in the FAR-database, it becomes evident that NICS(0), NICS(1), and NICS(1)ZZ present similar NICS aromaticity patterns for most of the systems. But the NICS aromaticity patterns found with NICS(0)ZZ in many cases do not agree with the NICS aromaticity patterns found with NICS(0), NICS(1), and NICS(1)ZZ. There are cases where the NICS(0)ZZ aromaticity pattern does not show an aromatic character at all. From XY NICS scan at planes from Z = 0 to Z = 1, it is found that as the Z-height is increased, the π-electron ring current effects are dominant, and the σ-bonding contributions are diminished. Therefore, it is recommended here to compute NICS(1)ZZ instead of NICS(0)ZZ when analyzing NICS of PAHs.

Neural networks methodology is a tool that allows to get the potential energy curve in cases where the data dispersion does not fit a discrete distribution; hence, a binding energy fitting can be found with this methodology. A data distribution of the intermolecular pair interaction potential in vacuum has been previously accomplished between asphaltene-asphaltene (U-AA) systems by using compass classical force field. In the latter, all possible interaction geometries are taken into account between the species: random, face-to-face, t-shape and edge to edge. In one of these cases, a potential energy curve is gotten when the geometry of interaction is face-to-face using a statistical fit. Focusing in these data distribution, neural networks have been applied on the following cases: i) face-to-face distribution of asphaltene-asphaltene interactions; ii) the complete asphaltene-asphaltene discrete distribution of energy vs contact distance (the minimum distance at which the interacting species is not equal to zero) where all-geometries were used, and iii) the random distribution of geometries of asphaltene-asphaltene interactions. In addition, using an asphaltene model molecule reported by Speight and taking into account two possible asphaltene interactions (face-to-face and random), firstly the data distribution of energy as a function of distance is obtained, and secondly neural networks are applied to fit the corresponding potential energy curve.

Although normally the copolymers used to remove water from crude oil have a block structure, two series of random acrylic copolymers were evaluated as petroleum demulsifiers. These acrylic copolymers, with two different butyl acrylate (BuA) and 2-ethylhexyl acrylate (2-EHA) contents, were synthesized by semi-continuous emulsion polymerization. Their weight-average molar mass () was varied by modifying the amount of chain transfer agent relative to the monomers from 0 to 8wt%. FTIR and C-13-NMR spectroscopies confirmed that the conversion of the monomers was complete. The synthesized acrylic copolymers were subsequently evaluated as demulsifier agents in a Mexican heavy crude oil (10.24 degrees API). Copolymers with 70wt% butyl acrylate monomer and a weight-average molar mass above of 11 000g mol(-1) presented the greatest ability to remove emulsified water from the system. The demulsifying capability of the copolymer was evidenced to be strongly dependent on their molecular mass. HighlightsSynthesis of random acrylic copolymers (BuA-co-2-EHA) of different average molar mass ().Evaluation of random acrylic copolymers as demulsifiers of heavy crude oil.Weight-average molar mass () and monomer composition play an important role on the performance of random acrylic copolymers as demulsifiers. [GRAPHICS] .

Aromaticity has been used as a criterion to explain the gas chromatographic (GC) retention of cata -condensed polycyclic aromatic sulfur heterocycles (PASHs) C 12 H 8 S, C 16 H 10 S, C 20 H 12 S; and peri -condensed PASHs C 18 H 10 S, in a GC column with 50% phenyl/50% dimethyl silphenylene polymer. To establish the aromaticity, nucleus-independent chemical shifts at the level of the molecular plane, NICS(0), and at 1 Å above the surface of the molecular plane, NICS(1), have been used. It has been found that the GC retention of cata -condensed PASHs C 12 H 8 S, C 16 H 10 S, and C 20 H 12 S is satisfactorily defined by the aromaticity of the entire molecule, and the GC retention of peri -condensed PASHs C 18 H 10 S is satisfactorily defined by the local aromaticity in the sulfur pentagonal ring. In addition, the positive slope between GC retention and NICS(0) of the entire molecule for cata -condensed PASHs, C 12 H 8 S and C 16 H 10 S, and by NICS(1) in the pentagonal ring for peri -condensed PASHs, C 18 H 10 S, is explained by the interaction between the electrons of the heterocycle molecule and the positive pole of the silicon atom in the GC column, as suggested with PAHs. In contrast, the negative slope between GC retention and aromaticity for cata -condensed C 20 H 12 S is explained by the presence of bay , cove , or fjord regions in the vicinity of the sulfur atom that generates either higher GC retention and lower aromaticity or lower GC retention and higher aromaticity.

Block copolymers PEO-PPO-PEO ,-functionalized with tertiary aliphatic or aromatic amines were synthesized to obtain a new type of ammonium salt. The compounds were evaluated as demulsifying agents in extra-heavy and heavy Mexican crude oils, 7.5 degrees and 17.8 degrees API. The grafting at the copolymer ends with trioctylamine and quinoline demonstrated to be the best functionalization for increasing the demulsifying efficiency in both crude oils. It was evidenced, for copolymers functionalized with aliphatic amines, that the length of the alkyl chain of the amine plays an important role in the potential to remove emulsified water. Furthermore, it was observed that higher positive value of log P parameter has a strong correlation with the performance of block copolymers functionalized with aliphatic amines. In the case of aromatic amines, the atomic charge of nitrogen proved to be an important factor to provoke the coalescence of the water drops. Finally, the molecular mass of block copolymer was also evaluated, showing that copolymers with higher < are more efficient to remove the water from crude oils with huge amounts of asphaltenes. [GRAPHICS] .

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A series of α,ω-diamines of polyoxyethylene–polyoxypropylene–polyoxyethylene (POE–POP–POE) triblock copolymer was synthesized and experimentally evaluated as dewatering agents for heavy crude oil. A quantitative structure–activity relationship (QSAR) study of the effect of the secondary amine structure over the yield of nucleophilic substitution reactions with α,ω-ditosylate ester of PEO–PPO–PEO triblock copolymer was performed exclusively at the DFT level. Multiple linear regression (MLR) analysis including softness or hardness parameters gave R2 = 0.9062, producing an equation with an acceptable rm(test)2 value. Furthermore, in order to understand the physicochemical interaction between the functionalizing copolymers and water, QSAR models based on AM1 semiempirical and DFT (B3LYP functional) descriptors were carried out for comparative purposes. For the MLR analysis at the AM1 level, R2 = 0.9058, whereas at the DFT level, R2 = 0.9879. 2-(Methylamino)ethanol was employed to evaluate the equations obtained. The residual of the log ERcalc SN2 reaction was −0.0043, showing a good correlation with experimental efficiency. Regarding water removal efficiency, the residuals of log WRcalc at the AM1 and DFT levels were of 0.0220 and 0.0041, respectively. Even though, DFT produced a better correlation, a QSAR study at the AM1 level could be employed to study the behavior of α,ω-diamines of PEO–PPO–PEO triblock copolymer and to destabilize water/oil emulsions, with a computational cost relatively low compared to DFT calculations.

A series of multibranched block copolymers was synthesized by means of anionic ring opening polymerization (AROP) techniques, using different alkoxide salts obtained from molecules that present different numbers of alcohol functions as initiators. Propylene oxide (PO) and ethylene oxide (EO) were polymerized in two steps, with the intent of obtaining multibranched block copolymers (PO/EO) with demulsifying activity in petroleum. The characterization of the polymers was done by means of size exclusion chromatography (SEC), Fourier transformed infrared spectroscopy (FTIR), carbon-13 nuclear magnetic resonance (C-13 NMR), and thermogravimetric analysis (TGA). A theoretical study by semiempirical AM1/NDDO has been carried out in order to explain the growth of multiple branches from the initiators during the early stages of the anionic polymerization. These simulations revealed complex patterns of polymer growth and increasing polydispersities when initiators with a greater number of active sites were employed to start the reactions. Afterward, the water removal efficiency, as a function of the number of copolymer branches, was evaluated through bottle tests in two crude oils: a heavy crude oil with 12.71 degrees API and an extra-heavy crude oil with 9.68 degrees API, with a water content of 47 and 39 vol %, respectively. A complex and nonlinear behavior of the water removal, as a function of the number of the block copolymer branches, was observed.

We present experimental evidence under low-dose conditions transmission electron microscopy for the unfolding of the evolving changes in carbon soot during mechanical milling. The milled soot shows evolving changes as a function of the milling severity or time. Those changes are responsible for the transformation from amorphous carbon to graphenes, graphitic carbon, and highly ordered structures such as morphed graphenes, namely Rh6 and Rh6-II. The morphed graphenes are corrugated layers of carbon with cross-linked covalently nature and sp2- or sp3-type allotropes. Electron microscopy and numerical simulations are excellent complementary tools to identify those phases. Furthermore, the TEAM 05 microscope is an outstanding tool to resolve the microstructure and prevent any damage to the sample. Other characterization techniques such as XRD, Raman, and XPS fade to convey a true identification of those phases because the samples are usually blends or mixes of the mentioned phases.

Jojoba oil is a naturally occurring vegetal oil, used widely in cosmetic, pharmaceutical, dietetic foods, animal feeding and as a constituent of bio-diesel. In addition, its use in petroleum conditioning has been reported. In this research, four samples of jojoba oil were carefully characterized and their performance as antifoaming agents in light crude oil was studied. A derivative of Simmondsia chinensis was characterized by different techniques such as Fourier transform infrared spectroscopy, nuclear magnetic resonance and size exclusion chromatography. Thermal degradation of jojoba oil was followed by thermogravimetry analysis (TG), differential scanning calorimetry and, primarily, TG coupled to Fourier Transform infrared spectroscopy. Furthermore, a molecular dynamic simulation was carried out in order to investigate the behavior of this compound when subject to thermal degradation. Assessments in light crude oil determined said vegetal oil to have a good performance level as a foam inhibitor at a low temperature (20 °C). Its high degree of thermal stability was also established through calorimetric techniques.