Transformation Of Hydrocarbons Research Articles

Molecular Analyses of Petroleum Hydrocarbon Change and Transformation during Petroleum Weathering by Multiple Techniques.

Various analytical techniques are used to study the weathering process of four crude oils, i.e., Iranian light crude oil, Daqing crude oil, Shengli crude oil, and Tahe crude oil. The molecular composition and structural information of n-alkanes, polycyclic aromatic hydrocarbons (PAHs), and heteroatom compounds were characterized by gas chromatography-flame ionization detector (GC-FID), gas chromatography-mass spectrometry (GC-MS), and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), respectively. The results showed that the weathering loss of n-alkanes was related to the molecular weight, and the low-molecular-weight (LMW) n-alkanes were more volatile. The loss degree of LMW naphthalene and alkylation homologues in PAHs was also higher. With the increase in the alkylation degree, the weathering resistance ability of PAHs was enhanced. In the negative-ion ESI FT-ICR MS mode, a total of 16 classes of compounds were detected for neutral nitrogen compounds and acidic compounds in the four crude oils. With the increase in weathering time, the relative abundances of NO, NO2, and O3S compounds gradually increased. In particular, the NO and NO2 compounds with different condensation degrees increased significantly. These results indicated that in addition to the volatilization of hydrocarbon compounds, nitrogen compounds were also oxidized to a certain extent during the weathering process. The provided information would enrich the understanding of the short-term weathering process of petroleum hydrocarbons.

An inorganic origin of the “oil-source” rocks carbon substance

On the basis of an inorganic concept of the petroleum origin, the phase relationships of crystalline kerogens of black shales and liquid oil at the physicochemical conditions of a typical geobarotherm on the Texas Gulf Coast are considered. At the conditions of the carbon dioxide (CO2) high fluid pressure, the process of oil transformation into kerogens of varying degrees of “maturity” (retrograde metamorphism) takes place with decreasing temperature and hydrogen pressure. Kerogen generation in black shale rocks occurs by the sequential transition through metastable equilibria of liquid oil and crystalline kerogens (phase “freezing” of oil). The upward migration of hydrocarbons (HC) of oil fluids, clearly recorded in the processes of oil deposit replenishment in oil fields, shifts the oil ↔ kerogen equilibrium towards the formation of kerogen. In addition, with decreasing of the hydrogen chemical potential as a result of the process of high-temperature carboxylation and low-temperature hydration of oil hydrocarbons, the “mature” and “immature” kerogens are formed, respectively. The phase relationships of crystalline black shale kerogens and liquid oil under hypothetical conditions of high fluid pressure of the HC generated in the regime of geodynamic compression of silicate shells of the Earth in the result of the deep alkaline magmatism development. It is substantiated that a falling of hydrogen pressure in rising HC fluids will lead to the transformation of fluid hydrocarbons into liquid oil, and as the HC fluids rise to the surface, the HC ↔oil ↔ kerogen equilibrium will shift towards the formation of oil and kerogen. It is round that both in the geodynamic regime of compression and in the regime of expansion of the mantle and crust, carboxylation and hydration are the main geochemical pathways for the transformation of oil hydrocarbons into kerogen and, therefore, the most powerful geological mechanism for the black shale formations.

Recycling of waste plastics to liquid fuel mixture over composite zeolites catalysts

Plastic waste production and consumption is increasing at an alarming rate with the increase of the human population, rapid economic growth, continuous urbanization, and changes in lifestyle. In addition, the short life span of plastic accelerates the production of plastic waste on a daily basis. Plastic waste recycling is carried out in different ways, but in most developing countries, open or landfill disposal is a common practice for plastic waste management. Plastic recycling into feedstocks, also known as chemical recycling, is encouraged all over the world. One such area is the thermal and catalytic thermal degradation of plastics into hydrocarbon fractions, which can be used as high-quality motor fuel after appropriate processing. Hydrocracking in the presence of a catalyst is a promising method of converting waste plastic materials to high quality liquid transportation fuels with decreased amounts of olefins and heteroatoms such as S, N, Cl, N, and O. The article deals with the study of hydrocracking of waste plastic into high quality liquid fuel on various catalysts based on natural zeolite deposits Taizhuzgen. The aim of the work is to determine the effect of new composite catalysts on the yield of liquid products by studying the specific surface and porous structure based on natural zeolite modified with Mо salt. It is established that the modification of natural zeolite with Mo affects the morphology of the catalyst, therefore, the obtained catalysts have different effects on the yield and composition of liquid fractions during the hydrogenation thermocatalytic transformation of hydrocarbons. The highest yield of liquid products (61.56%) was achieved using the 2% Mo/Taizhuzgen zeolite catalyst, which was chosen as optimal.

Evaluation of H-ZSM-5 Deactivation During Dimethyl Ether to Hydrocarbons Transformation Process

Hydrocarbons synthesis using transformation of methanol/dimethyl ether is of particular interest in connection with the possibility of using synthesized hydrocarbons not only as fuel but as components for basic organic synthesis to obtain organic acids, polymers and pharmaceuticals. However, catalysts deactivation, based on surface coking and dealumination, can be considered as one of the main problems for the wide application of this technology. Deactivation kinetics modeling can play a leading role for economic assessment of this process and for development of methods for catalysts activity and stability improving. Article devoted to approval three deactivation models. Simple linear deactivation model showed the possibility of its usage only in the first parts of the deactivation process, where kinetic curves are linear. An extra operator addition to this model for determination of deactivation rate change allowed to improve model reliability. To enhance model correlation with reaction mechanism additional model was developed using chemical equations for catalysts surface deactivation. This model application allowed to improve results accuracy, however measurement of surface active sites quantity is needed for this calcula

The diagenetic continuum of hopanoid hydrocarbon transformation from early diagenesis into the oil window

Hopanoid molecules are ubiquitous in sedimentary rocks and make up a significant proportion of sedimentary organic matter, oils, and bitumen. Due to their relatively stable chemical structure, they are generally well preserved in the rock record, making them extremely useful as biomarkers or geomarkers. Despite extensive industry and scientific interest, the early phase of their eogenetic and early diagenetic transformation has not been fully demonstrated or examined in a geologic setting. Most previous studies have focused on the oil window range from about 0.5–1.0 %VRo, and neglected transformations that happen at maturity levels below this. Additionally, the geological transformation of hopanoids has been extensively applied as a geochemical indicator of thermal maturity, however the mechanisms that result in these transformations are not fully understood.A major stumbling block in the study of hopanoid diagenesis is the availability of well constrained samples along a single stratigraphic horizon from very low maturity and through the oil window. This study utilizes a natural thermal maturity transect along a single stratigraphic horizon which stretches from thermally immature rocks, up to the middle of the oil window. The purpose of this study is to document the progressive changes in abundance of hopanoid hydrocarbon compound classes and between individual isomers with increasing thermal transformation. Samples for this study were taken from cores of the Upper Cretaceous Second White Specks Formation, a major source rock within the Western Canadian Sedimentary Basin, that has been extensively mapped and studied. This sample set represents a unique opportunity to examine the changes in hopanoid class with increasing thermal maturity.69 samples from 8 wells were examined for biomarkers. Thermal maturity was determined using HAWK programmed pyrolysis analysis of 87 samples from 9 wells. These geochemical methods were combined with a well established stratigraphic framework to ensure that sampling methods were stratigraphically controlled. Neohopenes, hopenes, ββ-hopanes, βα-hopanes, αβ-hopanes, and rearranged hopanes were differentiated and drastic changes in the proportions of these compound classes were observed with increasing thermal maturity. Thermally immature rocks are dominated by hopenes, neohopenes, and ββ-hopanes, whereas the middle of the oil window is dominated by αβ-hopanes and rearranged hopanes. These results allow a detailed determination of the maturity ranges that correspond to the transformation or disappearance of specific hopanoid molecule classes, for example the loss of hopenes in the maturity range of 0.28–0.35 %VRE. Additionally, this study allows the stages of episodic or punctuated transformations of hopanoid classes to be better delineated and narrowed down to specific maturity ranges. This work represents a novel examination of a natural thermal maturity transect and helps to consolidate our understanding of the early diagenetic transformations of hopanoid compounds.

A review on anaerobic microorganisms isolated from oil reservoirs.

The Role of microorganisms in the petroleum industry is wide-ranging. To understand the role of microorganisms in hydrocarbon transformation, identification of such microorganisms is vital, especially the ones capable of in situ degradation. Microorganisms play a pivotal role in the degradation of hydrocarbons and remediation of heavy metals. Anaerobic microorganisms such as Sulphate Reducing Bacteria (SRB), responsible for the production of hydrogen sulphide (H2S) within the reservoir, reduces the oil quality by causing reservoir souring and reduction in oil viscosity. This paper reviews the diversity of SRB, methanogens, Nitrogen Reducing Bacteria (NRB), and fermentative bacteria present in oil reservoirs. It also reviews the extensive diversity of these microorganisms, their applications in petroleum industries, characteristics and adaptability to survive in different conditions, the potential to alter the petroleum hydrocarbons properties, the propensity to petroleum hydrocarbon degradation, and remediation of metals.

Hydrothermal catalytic conversion and metastable equilibrium of organic compounds in the Jinding Zn/Pb ore deposit

Hydrothermal organic reactions in the presence of mineral catalysts have been well established by laboratory experiments. However, little is documented about hydrothermal catalytic conversion (HTCC) and the metastable existence of complex molecules in continental hydrothermal systems. Five freshly mined ores containing oil and solid bitumen and associated unmineralised host sediment were sampled from the Beichang mine, Jinding Zn/Pb ore deposit, Lanping, near the Indo-Eurasian collisional margin, southeastern Tibetan Plateau. Here we show evidence for a wide range of mineral (ZnS/PbS) catalysis of polycyclic aromatic compounds in the natural subsurface.An interpretation of hydrothermal alteration (non-biodegradation) was made for the unresolved complex mixture. From unmineralised host sediment through oils to the solid bitumen, a stepwise interaction of organic compounds with metal-bearing hydrothermal fluids was demonstrated by the transformation of polycyclic aromatic hydrocarbons (PAHs) and phenyl/sulfur/oxygen-containing compounds that are thought to be generated through HTCC. Thermodynamically-unstable phenyl derivatives (ortho- or α-substituted) resulted from hydrothermal alteration (ring opening) of the middle and naphthenic (low energy) rings of peri-condensed parent PAHs, as supported by the dominance of 1-phenyldibenzothiophene, 1-phenyldibenzofuran, triphenyleno[1,12-bcd]thiophene, triphenyleno[1,12-bcd]furan, 9-phenylphenanthrene, 1,1′:2′,1′′:2′′,1′′′-quaterphenyl, and the corresponding thiophenes or furans over other isomers. Heteroatom addition to phenyl-derivatives generates abundant heterocyclic compounds, which can undergo further dehydrocyclisation. In the presence of ZnS/PbS, the abundance of three compound classes (unsubstituted PAHs, ‘aryl-aryl’ linked phenyl-derivatives, and S/O atom-containing compounds) is mainly hydrothermally controlled, rather than thermodynamically controlled. Various phenyl/sulfur/oxygen-containing compounds are the metastable equilibrium products of a series of complex redox reactions under specific hydrothermal conditions. We hypothesise that the ubiquitous triphenyleno[1,12-bcd]furan is an important marker for hydrothermal organic–inorganic interactions in the Zn/Pb deposit. The relative abundance of 9-phenylphenanthrene provides a measure of the degree of hydrothermal alteration and HTCC. Our data is consistent with a close interaction of ascending metalliferous hydrothermal fluids with indigenous organic matter/compounds. Hydrothermal fluids, in the presence of sphalerite (and/or galena), are highly effective for activation of the carbon–carbon bonds in PAHs.

Hydrocarbon transformation pathways and soil organic carbon stability in the biostimulation of oil-contaminated soil: Implications of 13C natural abundance

Mineralization, assimilation, and humification are key processes to detoxify oil-contaminated soil by biostimulation remediation strategies, and these processes are affected by stimulants. In this study, we investigated the effects of either inorganic salts or organic stimulants (organic compost and sawdust) on hydrocarbon transformation. Total petroleum hydrocarbons (TPH) and hydrocarbon components were determined by gravimetry and gas chromatography, and the 13C of CO2, microbial biomass carbon (MBC), and humus were measured by stable isotope mass spectrometry. The results showed that organic compost was the most beneficial for the dissipation of hydrocarbons. After 60 days of remediation, the removal rates of TPH, saturates, aromatics, C7-C30 n-alkanes, and 16 PAHs were 35.7%, 39.6%, 15.9%, 80.5%, and 8.8%, respectively. A total of 84.7%–88.5% of the removed hydrocarbons were mineralized in all the treatments. The hydrocarbon degradation pathway in the control soil (without stimulant addition) was “assimilation → humification → mineralization”. The hydrocarbon transformation pathways in the biostimulation treatments were “assimilation → mineralization → humification”. The soil organic carbon (SOC) stability decreased during remediation, which was attributed to the enhanced microbial activity and the removal of recalcitrant hydrocarbons.

Deciphering the transformation mechanism of substituted polycyclic aromatic hydrocarbons on Al(III)-montmorillonite: An experimental and density functional theory study

The researches on transformation of polycyclic aromatic hydrocarbons (PAHs) on clay minerals modified by metal ions have received increasing attention. However, the transformation of PAHs with electron-withdrawing or electron-donating substitutional groups on clay minerals is not well understood currently. In this study, the degradation of anthracene (ANT) with different substituents (including -CH3, -CHO, -Br, -OMe, and -NO2) on Al(III)-montmorillonite (MMT) was investigated in the dark. The results showed that aromatic compounds were degraded with the rate constants (kobs) of 0.004–0.141 d−1. Moreover, ANT with electron-donating substituents (e.g., -CH3, -OMe) had a higher transformation rate than that with electron-withdrawing substituents (e.g., -Br, -NO2). The reactive oxygen species (ROS) quenching experiments indicated that ROS played a significant role in the transformation of ANT and ANT derivatives. Density functional theory (DFT) calculations revealed that the reactivity of single substituted PAHs was highly correlated with their ionization potential (IP), the energy of highest occupied molecular orbital (EHOMO), the energy of lowest unoccupied molecular orbital (ELUMO), and electronegativity (ζ), while independent of hardness (η). This study provides novel insights into predicting the reactivity of PAHs derivatives, and lays a fundamental basis for better understanding the fate of substituted PAHs in soils.

Microbial Succession under Freeze-Thaw Events and Its Potential for Hydrocarbon Degradation in Nutrient-Amended Antarctic Soil.

The polar regions have relatively low richness and diversity of plants and animals, and the basis of the entire ecological chain is supported by microbial diversity. In these regions, understanding the microbial response against environmental factors and anthropogenic disturbances is essential to understand patterns better, prevent isolated events, and apply biotechnology strategies. The Antarctic continent has been increasingly affected by anthropogenic contamination, and its constant temperature fluctuations limit the application of clean recovery strategies, such as bioremediation. We evaluated the bacterial response in oil-contaminated soil through a nutrient-amended microcosm experiment using two temperature regimes: (i) 4 °C and (ii) a freeze–thaw cycle (FTC) alternating between −20 and 4 °C. Bacterial taxa, such as Myxococcales, Chitinophagaceae, and Acidimicrobiales, were strongly related to the FTC. Rhodococcus was positively related to contaminated soils and further stimulated under FTC conditions. Additionally, the nutrient-amended treatment under the FTC regime enhanced bacterial groups with known biodegradation potential and was efficient in removing hydrocarbons of diesel oil. The experimental design, rates of bacterial succession, and level of hydrocarbon transformation can be considered as a baseline for further studies aimed at improving bioremediation strategies in environments affected by FTC regimes.

Utilization of CO2 in non-catalytic dry reforming of C1–C4 hydrocarbons

A kinetic and thermodynamic analysis of CO2 utilization through non-catalytic dry (carbon dioxide) reforming of light hydrocarbons C1– C4 in the temperature range of 1400–1800 K is performed. The sequence of stages of transformation of hydrocarbons into syngas and corresponding time intervals are determined. In this temperature range, methane is successively pyrolyzed into ethylene and then acetylene, the subsequent conversion of which leads to the formation of CO and H2. Hydrocarbons C2+ are also rapidly pyrolyzed mainly into ethylene and methane and then into acetylene, without any noticeable participation of CO2. The conversion of CO2 begins after a noticeable conversion of the hydrocarbons due to its reaction with H atoms formed in the system and leads to the formation of CO and OH radicals. The acetylene formed is mainly converted through its reaction with OH radicals. Then, the dry and steam reforming of the acetylene and methane residues yields the final products. The results obtained demonstrate the possibility of the efficient utilization of CO2 in the reforming of hydrocarbons with an enhanced yield of syngas.

Hydrocarbons in Water and Bottom Sediments in Kerch Strait

The article gives the results of studies of the concentration and composition of aliphatic hydrocarbons in suspension in surface water and in the surface layer of bottom sediments in April and September 2019 in Kerch Strait compared with other regions of the Black Sea. Notwithstanding the high concentrations of aliphatic hydrocarbons (especially, in the water of the strait itself, i.e., 110–160 µg/L and in sand sediments, i.e., 16–63 µg/g), the composition of alkanes was not of petroleum type because of the rapid transformation of petroleum hydrocarbons. The pollution of water and sediments in the strait manifested itself in a higher concentration of hydrocarbons in the composition of lipids and Corg, in the presence of naphthene-aromatic compounds in alkane composition, and in the predominance of phytane over pristine.

Assessment of the Bottom Sediments State After Oil Spill

The paper has deal with the monitoring of the lake bottom sediments which were contaminated by oil during emergency spill. The results of geochemical study of chloroform bitumoids extracted from sediment samples showed that the processes of transformation of oil hydrocarbons lasted for 10 years since the oil spill. This is indicated a decrease in the residual oil content and changes in the chemical composition of bitumoids. The hydrocarbons content was decreasing and resinous-asphaltene components was increasing as oxygen-containing groups and bonds in the chemical structure of bitumoids. In the individual composition of hydrocarbons the significant redistribution of saturated hydrocarbons was occurring both within the homologous series and between different homologous series, the CPI coefficient and the biodegradation coefficient Prophy/nC17+nC18 was increasing. By 2017 in absence of new oil spills the chemical composition of bottom sediments had closed to a state inherent in the native organic matter of bottom sediments of coastal lake facies, which characterized by the presence of compounds typical for higher plant lipids (dominance of high molecular weight n-alkanes of composition nC23–nC33 with a significant predominance of odd homologues, a high content of oxygen-containing compounds – solid saturated fatty acids, aliphatic esters and saturated ketones).

Zeolites as a tool for intensification of mass transfer on the surface of a cobalt Fischer–Tropsch synthesis catalyst

Zeolite-containing Co catalysts for Fischer–Tropsch synthesis (FTS) were investigated in catalytic transformations of liquid hydrocarbons thus emulating secondary transformations of FTS products. Three different zeolites were employed, namely HBeta, HZSM-5 and HY. The conditions for catalytic testing were similar to those observed during FTS, i.e. typical temperatures in 170–260 °C range and the presence of water as a main byproduct of FTS. The results of hydrocarbon transformation investigation were analyzed vs performance of those same catalysts in FTS. It was established that all three investigated zeolites caused lower average molecular weight of the products of both FTS and liquid hydrocarbon transformations thus clearing the pore system of the catalyst from heavier hydrocarbons. It is remarkable that, despite the average molecular weight drop, the introduction of zeolites does not lead to increase in methane selectivity at Co catalysts in FTS. It was shown, in particular, that the composition of FTS-generated liquid hydrocarbons C5+ depends primarily on the properties of a particular zeolite emplyed in the Co catalyst, more precisely on the number and availability of Brønsted acid centers since these centers determine the activity of a catalyst in cracking and isomerization. Cracking was revealed to be decisive in elimination of wax-like heavy hydrocarbons while isomerization and oigomerization balanced both molecular weight distribution and group composition. Thus, zeolites can be instrumental in controlling composition of the products of Fischer–Tropsch synthesis produced over hybrid catalysts due to intensification of mass transfer.

Engineering the Distinct Structure Interface of Subnano-alumina Domains on Silica for Acidic Amorphous Silica-Alumina toward Biorefining.

Amorphous silica–aluminas (ASAs) are important solid catalysts and supports for many industrially essential and sustainable processes, such as hydrocarbon transformation and biorefining. However, the wide distribution of acid strength on ASAs often results in undesired side reactions, lowering the product selectivity. Here we developed a strategy for the synthesis of a unique class of ASAs with unvarying strength of Brønsted acid sites (BAS) and Lewis acid sites (LAS) using double-flame-spray pyrolysis. Structural characterization using high-resolution transmission electron microscopy (TEM) and solid-state nuclear magnetic resonance (NMR) spectroscopy showed that the uniform acidity is due to a distinct nanostructure, characterized by a uniform interface of silica–alumina and homogeneously dispersed alumina domains. The BAS population density of as-prepared ASAs is up to 6 times higher than that obtained by classical methods. The BAS/LAS ratio, as well as the population densities of BAS and LAS of these ASAs, could be tuned in a broad range. In cyclohexanol dehydration, the uniform Brønsted acid strength provides a high selectivity to cyclohexene and a nearly linear correlation between acid site densities and cyclohexanol conversion. Moreover, the concerted action of these BAS and LAS leads to an excellent bifunctional Brønsted–Lewis acid catalyst for glucose dehydration, affording a superior 5-hydroxymethylfurfural yield.

The Known and Overlooked Sides of Zeolite‐Extrudate Catalysts

AbstractZeolite‐based catalysts play the essential roles in the production of fuel and commodity chemicals for the modern society. In general, the main component of zeolites powder has to be transformed into particular shapes in order to match the overall imperatives properties for the industrial applications. Shaping of zeolites catalysts was once only considered as the scale‐up or size‐enlarging processes of their innovated‐form. From the viewpoint of fundamental research, the shaping process was mainly defaulted as a mixing‐fabrication process at the macroscopic level without alterations to the intrinsic active sites at the molecular level. Such understandings have been already updated by a series of pioneering investigations by the innovative characterization techniques and methodologies. In the case of the zeolites extrudates, the mutual interactions among the binder, zeolite, and other functional additives, plus their consequences on the “new acidities” and porosities, have been unprecedentedly confirmed and visualized. Besides these significant achievements, the overlooked zeolites extrudates catalysts are related to the supported metal/metal oxide catalysts. This review further highlights the significant impacts of binders on the catalytic performance of zeolite‐based catalysts for the selected catalytic processes. The exemplary processes of hydrocarbon transformations (hydroisomerization and metathesis) show significant dependences on the introduction of binders, which are closely related with the “competitive effect” or “synergetic effect” in the dispersion or transformation of active sites for the reactions. The ever‐increasing disclosure of the overlooked sides may deepen and widen the understandings of the insights into the shaped zeolites catalysts.

Динаміка літогенезу осадових товщ фанерозою Карпато-Чорноморського регіону в аспекті їхньої нафтогазоносності

The objective of this work was to study the environments and processes of ancient sedimentation in the epi- and mesopelagic basins of the Carpathian-Black Sea region and to clarify the conditions of oil and gas basins formation within the study region as well as the main aspects of hydrocarbon generation. The burial history of the basins, some aspects of their fluid regime, issues of lithogenetic record, features of transformation of sedimentary basins into the rock-formation basins and the development of the latter during the Phanerozoic are considered. The spatial and temporal peculiarities of the evolution of epi-mesopelogic systems and their influence on the formation of oil- and gas-bearing strata within the Carpathian-Black Sea region have been studied. It has been established that in the sedimentary basins of the Carpathian-Black Sea continental margin of the Tethys Ocean during the long geological history the different intensity structural and morphological changes took place: changes of the subsidence rate of the basin bottom, inversion uplifts, sedimentation pauses, deformation of the sedimentary fill. This was reflected both in the peculiarities of the development of sedimentary environments and in the processes of substance differentiation with the formation of certain post-sedimentary mineral-structural parageneses. It was proved that discrete processes of differentiated compaction and defluidization of sediments cause a number of deformation phenomena, which can be reflected in the features of the morphology of the sedimentary basin bottom, influencing the nature of sediment transportation and accumulation. On the basis of the conducted investigations a number of practical results were obtained which will allow forming new approaches to criteria of hydrocarbons prospecting, in particular the lithophysical aspect which is concentrated on the reservoir properties of rocks; sedimentary reconstructions and the diversity of cyclicity of the studied sediments as a factor of the establishment of prospective areas, reconstruction of the burial history, which provides an information on the state of transformation of organic matter and hydrocarbons, and therefore the range of prospective depths for oil and gas occurrence.

Transformation of oil and hexadecane in soil by microbial preparations and earthworms

This study focuses on the effect of earthworms, oil-decomposing microbial preparation Destroil, and their combination on the destruction of oil in contaminated soil. The earthworms Eisenia andrei Bouché, 1972 accelerated the transformation of oil and hexadecane by microbiological preparations Destroil and Devouroil. The use of the combination of biological product and earthworms resulted in: (1) maximum reduction in the content of oil and hexadecane in the soil samples under study; (2) reduction of the phytotoxicity of oil-contaminated soil; (3) improvement in the agrophysical properties of soils in comparison with the action of these biodegradants separately. The transformation of oil hydrocarbons was monitored using NMR and IR spectroscopy. The biological oxidation process was accompanied by the accumulation of unsaturated triglycerides of variable structure. The chain length of the acid residue of triglycerides varied within the C11-C22 carbon atoms. In this case, the number of carbon atoms in the chain was most often -C18. The position of the double bonds was stochastic. At the same time, they were all removed from the carboxyl group by more than 4 carbon atoms. Stimulation of the processes of complex biotransformation of hexadecane under the action of the drug Devouroil and earthworms was manifested with the introduction of a biological product at concentrations of 32 × 1010 cells/kg and 64 × 1010 cells/kg. A further increase in the number of cells of the biological product Devouroil with the combined use of the biological product and worms led to a leveling of the stimulating effect of earthworms on the transformation processes of this hydrocarbon. At the same time, the phytotoxicity of the studied samples decreased.

Hydrocarbon transformations in sediments from the Cathedral Hill hydrothermal vent complex at Guaymas Basin, Gulf of California – A chemometric study of shallow seep architecture

Guaymas Basin isa submarine depression in the Gulf of California marking the northern end of the East Pacific Rise mid-oceanic spreading ridge.The basin receives high input of sedimentary organic matter (SOM) from elevated productivity in the overlying surface waters and runoff from the surrounding continent. This, coupled with high sedimentation rates, produces near-uniform compositions of SOM.Various hydrothermal vent complexes occur along this margin. One of these is Cathedral Hill, a hydrothermal mound with sulfide chimneys surrounded by mats dominated by sulfide-oxidizing Beggiatoa, covering sediments stained by locally produced oil. We collected four push cores along a transect at this site (4 m × 0.21 m) extending from near the vent center to the ambient sediment just outside the microbial mat cover. Porewater temperatures near the mound center were projected to reach 155 °C by 21 cm below the sea floor (cmbsf). Within these conditions, a kinetic model based on vitrinite reflectance equivalence (%Re) predicts petroleum formation as shallow as 15–18 cmbsf, with metagenesis commencing at <60 cmbsf. Bulk extract data (total lipid extracts as well as polar and apolar fractions), solvent-extracted sediment TOC (herein referred to as protokerogen TOC), and molecular thermal maturation parameters support these generation estimates. In recent years, the application of chemometric techniques tocomprehensive two-dimensional gas chromatographic (GC × GC) analyses has allowed comparison of thousands of unique hydrocarbons within oils. Here we reconstruct the shallow subsurface petroleum system by applying multiway principal component analysis (MPCA) and hierarchical cluster analysis (HCA)directly to GC × GC chromatograms. We then compare the resulting multivariate models to a systematic survey of subtracted GC × GC chromatograms, a transect heat map of sample hydrocarbon compound diversities, and profiles of various thermal maturation parameters to elucidate how these hydrocarbon matrices are attenuated by production, migration, and/or thermochemical oxidation. Sample matrices have up to 5800 unique compounds spanning a range ofnormal and branched alkanes, saturated and unsaturated biomarkers, substituted and unsubstituted polycyclic aromatic hydrocarbons (PAHs), perhydro-PAHs, and benzothiopheneswith up to six ring-cycles (i.e., benzoperylenes, dibenzopyrenes, dibenzochrysenes, and indenopyrenes). These matrices display systematic temperature-dependent trends. Generation likely begins in 6–10 and 15–18 cmbsf where sediments are exposed to ∼115 °C vent porewater temperatures, which is shallower than predictions based on our kinetic model. Independent of these sites of generation is ubiquitous staining of the sediments from advected oil that is heavily dominated by PAHs as well as two stratigraphic bandsof migrated oil that extend horizontally across the transect at 0–2 and ∼6–10 cmbsf, respectively.The MPCA models along with non-statistical validation techniques show evidence of decreasingdiversities and concentrations of alkylated aromatic hydrocarbons concomitant with elevated abundances of dealkylated PAHs and/or the migration of unsubstituted PAHs from deeper basin depths as sediments become exposed to more severe hydrothermal conditions. These results indicate that even at relatively small spatial scales, the petroliferous sediments at hydrothermal vent sites can be highly complex.

Electrochemical 1,2‐Diarylation of Alkenes Enabled by Direct Dual C–H Functionalizations of Electron‐Rich Aromatic Hydrocarbons

AbstractA cobalt‐promoted electrochemical 1,2‐diarylation of alkenes with electron‐rich aromatic hydrocarbons via direct dual C−H functionalizations is described, which employs a radical relay strategy to produce polyaryl‐functionalized alkanes. Simply by using graphite rod cathode instead of platinum plate cathode, chemoselectivity of this radical relay strategy is shifted to the dehydrogenative [2+2+2] cycloaddition via 1,2‐diarylation, annulation, and dehydrogenation cascades leading to complex 11,12‐dihydroindolo[2,3‐a]carbazoles. Mechanistical studies indicate that a key step for the radical relay processes is transformations of the aromatic hydrocarbons to the aryl sp2‐hybridized carbon‐centered radicals via deprotonation of the corresponding aryl radical cation intermediates with bases.