Oxidation Products Of Hydrocarbons Research Articles

Microwave plasma torch desorption ionization mass spectrometry for chemical characterization of aromatic secondary organic aerosol

Benzene and toluene, primarily emitted from vehicle exhaust, are common volatile organic compounds (VOCs). These aromatic compounds in the atmosphere undergo further photooxidation to form secondary organic aerosol (SOA), which are a primary factor in haze weather. Aromatic SOA is more difficult to detect by traditional detection methods. Microwave plasma torch (MPT) is an ambient ionization source based on microwave plasma developed in recent years. Herein, a microwave plasma torch desorption ionization high-resolution mass spectrometry (MPT-HRMS) technique was designed for the direct analysis of aromatic SOA in the environment. For environmental haze samples, no pretreatment is required, and over twenty types of aromatic hydrocarbon derivatives or oxidation products can be detected in situ using MPT-HRMS. The possible mechanisms underlying the formation of aromatic SOA were investigated. MPT-HRMS is a powerful technical tool for rapidly tracking non-targeted aromatic SOA and their transformations in the environment. This contributes to an in-depth understanding of the formation mechanisms of SOA and their impact on air pollution.

OXIDATION OF ALKYLAROMATICS BY OXYGEN IN THE DIELECTRIC BARRIER DISCHARGE

The oxidation of cumene with oxygen in a barrier discharge under conditions of effective removal of reaction products from the reactor has been studied. The experiments were carried out on a setup with an electrochemical reactor with a barrier discharge in a flow mode. The results are presented in comparison with the previously studied oxidation of benzene and toluene. The main products of cumene oxidation are acetophenone and dimethylphenylcarbinol, the total selectivity of which reaches 78%wt. Phenol and other compounds with a hydroxyl group in the aromatic ring were not found in significant amounts. Cumene conversion in the studied temperature range varies from 1.0%wt to 1.2%wt. In the case of toluene, the main products are cresols, benzaldehyde and benzyl alcohol (in total 77%wt). The main product of the oxidation of benzene is phenol (up to 74% by weight), diatomic phenols, mainly hydroquinone, also are found. Based on the research results, a probable mechanism of oxidation of aromatic hydrocarbons by oxygen in a barrier discharge is proposed. It is shown that the general direction of oxidation of aromatic hydrocarbons is determined by the contribution of two processes of its oxidation – with the participation of atomic oxygen and along the route of autooxidation. The data obtained make it possible to reasonably predict the composition of oxygen oxidation products of various aromatic hydrocarbons under barrier discharge conditions. The revealed regularities make it possible to evolve methods for controlling the oxidation of aromatic hydrocarbons in a low-temperature plasma of a barrier discharge based on temperature control of the process. The results obtained will become the basis for the development of new environmentally friendly methods of organic synthesis involving aromatic compounds using low-temperature nonequilibrium plasma of various discharges, including barrier, in accordance with the principles of "green chemistry". For citation: Leshchik A.V., Ochered'ko A.N., Ryabov A.Yu., Kudryashov S.V. Oxidation of alkylaromatics by oxygen in the dielectric barrier discharge. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 8. P. 15-21. DOI: 10.6060/ivkkt.20246708.16t.

Non-target analysis of crude oil photooxidation products at high latitudes and their biological effects

With new oil and gas lease sales in high-latitude regions, there exists a need to better understand the chemical fate of spilled oil and its effects on biological life. To address this need, laboratory simulations of crude oil spills under sub-Arctic conditions were conducted using artificial seawater and exposure to solar irradiation to create Hydrocarbon Oxidation Products (HOPs). HOPs characterization and their biological effects were assessed using ultra high-performance liquid chromatography (UHPLC) with high resolution mass Orbitrap spectrometry and the aryl hydrocarbon receptor (AhR) chemically activated luciferase gene expression (CALUX) assay. Non-target UHPLC-Orbitrap mass spectrometry analysis identified 251 HOPs that were in greater abundance in light-exposed samples than dark controls. Oxidized polycyclic aromatic hydrocarbons were also detected, including phenanthrene quinone, anthraquinone, hydroxyanthraquinone, and 9-fluoreneone. The composition of HOPs were consistent with photo-products of alkylated two to four ring PAHs, primarily compounds between 1 and 3 aromatic rings and 1–3 oxygens. The HOP mixture formed during photochemical weathering of Cook Inlet crude oil induced greater AhR activity than parent petroleum products solubilized in dark controls, indicating that HOPs, as a complex mixture, may contribute to petroleum toxicity more than the parent petroleum compounds. These non-targeted approaches provide the most comprehensive analysis of hydrocarbon oxidation products to date, highlighting the diversity of the complex mixture resulting from the photooxidation of crude oil and the limitations of targeted analyses for adequately monitoring HOPs in the environment. Taken together, these data identify a critical “blind spot” in environmental monitoring and spill clean-up strategies as there is a diverse pool of HOPs that may negatively impact human and ecosystem health.

Photochemical mobilization of dissolved hydrocarbon oxidation products from petroleum contaminated soil into a shallow aquifer activate human nuclear receptors

Elevated non-volatile dissolved organic carbon (NVDOC) concentrations in groundwater (GW) monitoring wells under oil-contaminated hydrophobic soils originating from a pipeline rupture at the National Crude Oil Spill & Natural Attenuation Research Site near Bemidji, MN are documented. We hypothesized the elevated NVDOC is comprised of water-soluble photooxidation products transported from the surface to the aquifer. We use field and laboratory samples in combination with complementary analytical methods to test this hypothesis and determine the biological response to these products. Observations from optical spectroscopy and ultrahigh-resolution mass spectrometry reveal a significant correlation between the chemical composition of NVDOC leached from photochemically weathered soils and GW monitoring wells with high NVDOC concentrations measured in the aquifer beneath the contaminated soil. Conversely, the chemical composition from the uncontaminated soil photoleachate matches the NVDOC observed in the uncontaminated wells. Contaminated GW and photodissolution leachates from contaminated soil activated biological targets indicative of xenobiotic metabolism and exhibited potential for adverse effects. Newly formed hydrocarbon oxidation products (HOPs) from fresh oil could be distinguished from those downgradient. This study illustrates another pathway for dissolved HOPs to infiltrate GW and potentially affect human health and the environment.

ANALYSIS OF COLICS (FOENICULUM VULGARE) SYRUP PREPARATION CONTAINING ESSENTIAL OILS BY GAS CHROMATOGRAPHY

Introduction. One of the important tasks facing pharmaceutical science is the search for sources of plant preparations, rich in various groups of biologically active substances the selection of biologically active substances from these sources and the creation of new medicines based on them. The aim of the study was conducting an analysis of the drug Colics (foeniculum vulgare), which contains essential oils by Gas Chromatography. Matherial and methods. Foeniculum vulgare, called fennel ordinary, is an erect, branching perennial plant, which is commonly grown in vegetable and herb gardens for its foliage and seeds, with anise-flavored, which are usually collected for culinary use. The analysis was carried out on an Agilent 7890B Gas Chromatograph and Chromatography-mass MS 5977A spectrometer. Column size 30 m*250 μm*0.25 μm brand HP-5 MS Ultra Inert. Split- the sample is divided into 20 parts, the first part is introduced into the apparatus. The initial temperature of 50°C is maintained for 2 minutes. Then, for each minute the temperature rises by 5°C and reaches 250°C and is held for 5 mi nu tes. Hexane was used as a solvent, as a carrier gas was used (He) 1.0 ml/min. Results. As a result of the analysis, 32 components were obtained. These compounds are mainly terpenoids and various oxidation products of saturated hydrocarbons. Compounds - 9, 10, 21, 22, 23, 24, 25, 27 predominate in the analyzed syrup «Colix».

Photochemical formation of water-soluble oxyPAHs, naphthenic acids, and other hydrocarbon oxidation products from Cook Inlet, Alaska crude oil and diesel in simulated seawater spills

Hydrocarbon oxidation products (HOPs) formed from crude oil and diesel were generated from laboratory simulated spills at four different periods (1, 4, 7, and 10 days) under environmental conditions that mimicked those in Cook Inlet, Alaska.

Catalyst-Free Oxidation Reactions in a Microwave Plasma Torch-Based Ion/Molecular Reactor: An Approach for Predicting the Atmospheric Oxidation of Pollutants.

The atmospheric oxidation of chemicals has produced many new unpredicted pollutants. A microwave plasma torch-based ion/molecular reactor (MPTIR) interfacing an online mass spectrometer has been developed for creating and monitoring rapid oxidation reactions. Oxygen in the air is activated by the plasma into highly reactive oxygen radicals, thereby achieving oxidation of thioethers, alcohols, and various environmental pollutants on a millisecond scale without the addition of external oxidants or catalysts (6 orders of magnitude faster than bulk). The direct and real-time oxidation products of polycyclic aromatic hydrocarbons and p-phenylenediamines from the MPTIR match those of the long-term multistep environmental oxidative process. Meanwhile, two unreported environmental compounds were identified with an MPTIR and measured in the actual water samples, which demonstrates the considerable significance of the proposed device for both predicting the environmental pollutants (non-target screening) and studying the mechanism of atmospheric oxidative processes.

Rapid growth of anthropogenic organic nanoparticles greatly alters cloud life cycle in the Amazon rainforest.

Aerosol-cloud interactions remain uncertain in assessing climate change. While anthropogenic activities produce copious aerosol nanoparticles smaller than 10 nanometers, they are too small to act as efficient cloud condensation nuclei (CCN). The mechanisms responsible for particle growth to CCN-relevant sizes are poorly understood. Here, we present aircraft observations of rapid growth of anthropogenic nanoparticles downwind of an isolated metropolis in the Amazon rainforest. Model analysis reveals that the sustained particle growth to CCN sizes is predominantly caused by particle-phase diffusion-limited partitioning of semivolatile oxidation products of biogenic hydrocarbons. Cloud-resolving numerical simulations show that the enhanced CCN concentrations in the urban plume substantially alter the formation of shallow convective clouds, suppress precipitation, and enhance the transition to deep convective clouds. The proposed nanoparticle growth mechanism, expressly enabled by the abundantly formed semivolatile organics, suggests an appreciable impact of anthropogenic aerosols on cloud life cycle in previously unpolluted forests of the world.

Evaluation of Ca2CuO3 as an oxygen carrier material

Oxygen release from Ca2CuO3 during its reductive decomposition was studied at temperatures of 700–900 °C by coulometric titration. The obtained results allow characterizing Ca2CuO3 as a promising oxygen carrier material (OCM) for the chemical looping combustion (CLC) process in the mode of its decomposition to CaO and Cu2O. This mode provides an oxygen storage capacity (OSC) of ~8.3 wt%, a high rate of oxygen release/uptake, good phase recovery in the redox cycle, and hydrocarbon oxidation products free of CO. In contrast, the stage of Cu2O decomposition to metal copper is characterized by very slow kinetics of redox processes that makes its involvement in CLC unfavorable.

The oxidation mechanism investigation of benzene catalyzed by palladium nanoparticle: A ReaxFF molecular dynamics

The precious metal palladium has exhibited well catalytic effect on soot oxidation. In order to study the catalytic mechanism of palladium on soot oxidation, the oxidation process of benzene (C6H6), an important soot precursor, on the surface of palladium (Pd) particles is studied by reactive force field molecular dynamics (ReaxFF MD). The possible reaction pathways of C6H6 oxidation and state conversion of metal Pd during the oxidation process are discussed. The results show that C6H6 is mainly oxidized through dehydrogenation, until the hydrogen number is less than 3, then the oxygenation reaction gradually dominates. The intermediate species, most of which is C6HO. For the important step of C6H6 oxidation, the ring-open is more likely to occur at the oxygen-containing site (accounted for 88%), and C2 species are mainly final products under current simulation conditions. The oxygen migration is then investigated, and the results show that the dissociated oxygen will entrance the Pd-lattice with the gaseous oxygen consumed, and finally return to the outer-surface. It is interesting to note that the oxygen in hydrocarbon oxidation products mainly (over 57%) comes from the Pd-inner lattice even during the period of the dissociated oxygen atoms keeping balance. This may be helpful to understand the coexistence of Pd and PdO during the oxidation process that found in the experiments.

Formation of Polycyclic Aromatic Hydrocarbon Oxidation Products in α-Pinene Secondary Organic Aerosol Particles Formed through Ozonolysis.

Accurate long-range atmospheric transport (LRAT) modeling of polycyclic aromatic hydrocarbons (PAHs) and PAH oxidation products (PAH-OPs) in secondary organic aerosol (SOA) particles relies on the known chemical composition of the particles. Four PAHs, phenanthrene (PHE), dibenzothiophene (DBT), pyrene (PYR), and benz(a)anthracene (BaA), were studied individually to identify and quantify PAH-OPs produced and incorporated into SOA particles formed by ozonolysis of α-pinene in the presence of PAH vapor. SOA particles were characterized using real-time in situ instrumentation, and collected on quartz fiber filters for offline analysis of PAHs and PAH-OPs. PAH-OPs were measured in all PAH experiments at equal or greater concentrations than the individual PAHs they were produced from. The total mass of PAH and PAH-OPs, relative to the total SOA mass, varied for different experiments on individual parent PAHs: PHE and 6 quantified PHE-OPs (3.0%), DBT and dibenzothiophene sulfone (4.9%), PYR and 3 quantified PYR-OPs (3.1%), and BaA and benz(a)anthracene-7,12-dione (0.26%). Further exposure of PAH-SOA to ozone generally increased the concentration ratio of PAH-OPs to PAH, suggesting longer atmospheric lifetimes for PAH-OPs, relative to PAHs. These data indicate that PAH-OPs are formed during SOA particle formation and growth.

Alkanes and aliphatic carbonyl compounds in wintertime PM2.5 in Beijing, China

Organic aerosol is one of the dominant components of PM2.5 in megacities. In order to understand the sources and formation processes of aliphatic carbonyl compounds, the concentrations of saturated and unsaturated aliphatic hydrocarbons and carbonyl compounds were determined in the PM2.5 from an urban area of Beijing sampled in November–December 2016 and analysed using two dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC x GC-TOFMS). The data were separated into non-haze and haze days (PM2.5 ≥ 75 μg m−3). n-Alkanes (C10-C36) and n-alkenes (C12-C26) were abundant in the samples during the sampling campaign regardless of non-haze and haze conditions, and the middle chain length n–alkanes (C25–C34) were the most abundant. Aliphatic carbonyls, specifically n-alkanals (C8-C29), n-alkan-2-ones (C8-C31) and n-alkan-3-ones (C8-C30) were also detected in the PM2.5 at concentrations much lower than n-alkanes. The n-alkanals were the most abundant compounds amongst the aliphatic carbonyls, accounting for 65.4% on average of the total mass of aliphatic carbonyls. For the non-haze days, it seems likely that the OH oxidation of n-alkanes was a source of carbonyl compounds, whereas vehicle exhaust makes a significant contribution to the n-alkanes and n-alkanals, but makes a much smaller contribution to the n-alkan-2-ones and n-alkan-3-ones. It appears that primary sources are likely to be a major contributor to concentrations of the high molecular weight carbonyl compounds during the haze episodes, probably deriving from coal combustion. In addition, furanones (γ-lactones) and phytone (6, 10, 14-trimethylpentadecan-2-one) were also detected in our samples and are oxidation products of hydrocarbons and a marker of biogenic input, respectively. Cooking emissions also appear to be a likely contributor to the furanones. This study provides new information on the profiles of PM2.5-associated aliphatic hydrocarbons and carbonyl compounds, and gives insights into their sources. Differences in the concentrations and ratios of carbonyl compounds between Beijing and London are discussed.

Profiling quinones in ambient air samples collected from the Athabasca region (Canada)

This paper presents new findings on polycyclic aromatic hydrocarbon oxidation products–quinones that were collected in ambient air samples in the proximity of oil sands exploration. Quinones were characterized for their diurnal concentration variability, phase partitioning, and molecular size distribution. Gas-phase (GP) and particle-phase (PM) ambient air samples were collected separately in the summer; a lower quinone content was observed in the PM samples from continuous 24-h sampling than from combined 12-h sampling (day and night). The daytime/nocturnal samples demonstrated that nighttime conditions led to lower concentrations and some quinones not being detected. The highest quinone levels were associated with wind directions originating from oil sands exploration sites. The statistical correlation with primary pollutants directly emitted from oil sands industrial activities indicated that the bulk of the detected quinones did not originate directly from primary emission sources and that quinone formation paralleled a reduction in primary source NOx levels. This suggests a secondary chemical transformation of primary pollutants as the origin of the determined quinones. Measurements of 19 quinones included five that have not previously been reported in ambient air or in Standard Reference Material 1649a/1649b and seven that have not been previously measured in ambient air in the underivatized form. This is the first paper to report on quinone characterization in secondary organic aerosols originating from oil sands activities, to distinguish chrysenequinone and anthraquinone positional isomers in ambient air, and to report the requirement of daylight conditions for benzo[a]pyrenequinone and naphthacenequinone to be present in ambient air.

IMPACT OIL-POLLUTED ON BIOLOGICAL SYSTEMS IN THE NORTHERN REGIONS OF SIBERIA

Goal. Establishment of the basic laws of physical and chemical composition of the oil of the north of Western Siberia and the assessment of their potential danger to biological systems in the event of accidental spills. Methods. The objects of the physic-chemical and microbiological tests were samples of water and soil of oil-producing complexes oil fields of northing Western Siberia. Oil concentration in soil samples were determined method of extract with chloroform to Soxhlet under reflux. The extracts were combined, freed from the chloroform by rotary evaporation. The oil is weighed and the concentration of pollution each soil sample find out in g/kg. Oil samples from the sampled water were extracted three times with chloroform. The extracts are separated from the water to a separating funnel, were combined and freed of chloroform by rotary evaporation. The concentration of water contamination was determined in mg/dm 3 . Oil from the soil analyzed by FTIR spectrometry Nikolet 5700 spectrometer (Thermo Electron Corporation, USA). The number of sample scans - 64, the measurement duration - 76.5 seconds, resolution - 4.000 interpolation rate - 0. The spectra were in the range from 400 to 4000 cm -1 . According to IR analyses calculate a coefficient of oxidation (K o ) against optical density values of the absorption bands: K o = D 1710 cm -1 /D 1465 cm -1 , which characterizes the destructive activity of the natural microflora. The absorption band 1710 cm -1 confirms the presence of oxygenated hydrocarbon oxidation products of oil, which include: carboxylic acids, ketones, aldehydes, aromatic and aliphatic esters. The presence of the band 1465 cm -1 absorption of the methylene groups defines various hydrocarbon structures in petroleum contaminant [1]. The total number of heterotrophic microorganisms involved in the recycling of oil processes in soil and water samples was determined by plating on meat-peptone (IPA) and starch-ammonia (SAA) agar to determine the hydrocarbon-oxidizing (DRR) of bacteria and actinomycetes, respectively [2]. The number of microorganisms was determined by the number a colony forming units (CFU) in one ml (water) or g (soil). In order to determine the area of oil pollution in the difficult, swampy territory used methods of processing and interpretation of space images [3]. Results. Is identified oil properties, which have the most negative impact on the environment and biological systems of northern Western Siberia regions. Is revealed deposits with the oil. Is researched oil-contaminated area using ground and satellite data. Is identified the concentrations of oil in the samples of soil, surface water and bottom sediments. Is revealed the number and activity of the microflora, its ability to utilize hydrocarbons. Conclusion. Results of evaluation of the ecological state of oil-contaminated landscapes in oil producing companies have shown that the main polluters of the river system are oil and oil products, the concentration of which exceeds MPC by 3-6 times. The method of gas chromatography-mass spectrometry in the oil extracted from the contaminated samples soil of Soviet field, identified a number of hydrocarbons: alkanes normal and isoprenoid structures, alkyl benzenes, polyaromatic hydrocarbons and dibenzothiophene, are hazardous to living organisms and humans if contaminated rivers during floods and heavy rains. Emerged problems of fresh drinking water quality in the territory of Western Siberia as a result of anthropogenic effect of local and global scale. Present high risk of contamination because of numerous transition points pipelines through small rivers on the territory of oil fields. High pollution concentrations (29-60 g/kg) and low levels of abundance and activity of microorganisms in conditions of the northern regions define a long process of self-purification of soil and surface water. GIS-technologies, mathematical calculations, physic-chemical and microbiological research methods allow timely to assess the scale of the territory contamination, determine the concentration and composition of pollutants and plan remediation events in inaccessible swampy areas of oil producing companies. Effective methods of remediation and measures of prevention to prevent accidents on the pipeline will undoubtedly improve the quality of river water and solve the problems of the relationship between the environment and man.

Particulate hydroxy-PAH emissions from a residential wood log stove using different fuels and burning conditions

Hydroxylated polycyclic aromatic hydrocarbons are oxidation products of polycyclic aromatic hydrocarbons, but have not been studied as extensively as polycyclic aromatic hydrocarbons. Several studies have however shown that hydroxylated polycyclic aromatic hydrocarbons have toxic and carcinogenic properties. They have been detected in air samples in semi urban areas and combustion is assumed to be the primary source of those compounds. To better understand the formation and occurrence of particulate hydroxylated polycyclic aromatic hydrocarbons from residential wood log stove combustion, 9 hydroxylated polycyclic aromatic hydrocarbons and 2 hydroxy biphenyls were quantified in particles generated from four different types of wood logs (birch, spruce, pine, aspen) and two different combustion conditions (nominal and high burn rate). A previously developed method utilizing liquid chromatography – photo ionization tandem mass spectrometry and pressurized liquid extraction was used. Polycyclic aromatic hydrocarbons were analyzed along with hydroxylated polycyclic aromatic hydrocarbons. The hydroxylated polycyclic aromatic hydrocarbon emissions varied significantly across different wood types and burning conditions; the highest emissions for nominal burn rate were from spruce and for high burn rate from pine burning. Emissions from nominal burn rate corresponded on average to 15% of the emissions from high burn rate, with average emissions of 218 μg/MJfuel and 32.5 μg/MJfuel for high burn rate and nominal burn rate, respectively. Emissions of the measured hydroxylated polycyclic aromatic hydrocarbons corresponded on average to 28% of polycyclic aromatic hydrocarbons emissions.This study shows that wood combustion is a large emission source of hydroxylated polycyclic aromatic hydrocarbons and that not only combustion conditions, but also wood type influences the emissions of hydroxylated polycyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons. There are few studies that have determined hydroxylated polycyclic aromatic hydrocarbons in emissions from wood combustion, and it is therefore necessary to further investigate the formation, occurrence and distribution of these compounds as they are present in significant amounts in wood smoke particles.

About the Рroblems of Design of Furnaces-Satellites for Environmentally Safe Burning of Old Railway Sleepers

Presents the results of experimental and theoretical studies of burning old sleepers in the combustion chamber of the combined type. Theoretical studies were carried out using the program ANSYS FLUENT. The experiments were conducted on a specially designed stand. The experiments measured the temperature of the combustion products; complete gas composition at the outlet of the flue pipe; flow rate and the temperature of the air supplied to the furnace. The experiments showed that in addition to the products of pyrolysis and oxidation of wood (СН 2 О, CH 3 OH, etc.) in flue gases are highly toxic and the oxidation products of aromatic hydrocarbons. Intensification unterkuernach processes by combining the scheme for supplying air jets in the combustion chamber not solve the problem. The decision of the authors of a joint burning old sleepers in the furnaces of satellites connected to industrial power boilers with discharge of combustible gases in the furnace of this boiler is technically correct.

Post - sedimentation influence on filtration capacity reservoir rock properties (Pur-Tazov oil\\gas-bearing area)

The processes of the second mineral formation (kaolinite, carbonates and micas) were identified during the post-sedimentation transformation studies in oil\\gas deposits. Besides, quartz regeneration, solid product destructive formation processes and hydrocarbon oxidation processes were -determined. Correlation analysis of the mineralogy and petrophysics data revealed the post-sedimentation influence factors on the reservoir properties of deposits. It should be noted that the second kaolinite composition increase results in water saturation and density decrease, porosity and, especially, permeability increase. Quartz regeneration and second mica formation deteriorate the reservoir properties or poorly influence them. The hydrocarbon decay and oxidation products, as well as secondary carbonate seal the void space, replace the soluble rock debris and sharply deteriorate the reservoir properties of oil andgas deposits.

Oxidative dihydroxylation of alicyclic unsaturated hydrocarbons with vinyl- and norbornene fragments in pseudohomogenic system

Oxidation of alicyclic unsaturated hydrocarbons (4-vinylcyclohexene, 5-vinylnorbornene, 5-cyclohexenylnorbornene, and 5-vinylbicyclooctene) with 30% hydrogen peroxide solutions and percarbamide is studied. Reaction was carried out at 40–70°C in the presence of heterogenized peroxocomplex compounds of molybdenum and tungsten formed “in situ” in the reaction of metal oxohalides with H3PO4, nano-dimensional particles of carbon material, and hydrogen peroxide. Main oxidation products of alicyclic diene hydro-carbons are the corresponding unsaturated epoxides and diols. Depending on the reaction condition their ratio varies in a wide range.

Production of Lipid and Fatty Acids during Growth of Aspergillus terreus on Hydrocarbon Substrates

An Aspergillus terreus, isolated from oil contaminated soil, could degrade a wide range of petroleum hydrocarbons including the immediate oxidation products of hydrocarbons, like alkanols and alkanals. Among all the linear chain carbon substrates, highest growth of 39.1 + or - 3.8 g l(-1) (wet weight) was observed when n-hexadecane was used as the sole source of carbon. The growth of the fungus on this highly hydrophobic substrate was associated with the morphological change of the hyphae and increase production of lipid in the cells. The lipid production in the hydrocarbon (n-hexadecane) grown cells was sevenfold higher than the corresponding glucose grown cells. The fatty acid profile of the lipid content formed in the hydrocarbon grown cells was significantly different from the glucose grown cells and was composed of fatty acids with chain length C(14) to C(33) as revealed from the liquid chromatography electrospray ionization mass spectrometry analyses. Among the ranges, the fatty acids with chain lengths C(14) to C(18) were predominant in the profile. Considering the fatty acid profile and the high level of lipid production, this A. terreus mediated production of lipid is envisaged to have potential application in the oleochemical industries including the production of biodiesel.

A quantum-chemical study of the interaction of the HeT+ ion with cycloalkanes and their oxidation products

The RHF/6-311G*(3d), RHF/6-311++G**(3df, 3p) and MP2/6-311G*(3d) ab initio methods were used to calculate the equilibrium structure of the products of the ion-molecular reaction of tritium ion transfer from HeT+ to cyclopentane and cyclohexane. Similar reactions with cyclopentanol and cyclopentanone were calculated at the RHF/6-311G*(3d) level. The interaction of HeT+ with cycloalkanes was found to produce onium ions with cyclic structures, in which the tritium atom held neighboring methylene groups together. With the alcohol and ketone, not only cyclic but also stabler linear cations could be formed, and the addition of the tritium ion directly to the oxygen atom was possible. The suggestion was made that the chain of tritium ion transfer reactions was the mechanism of the accumulation of tritium by hydrocarbon oxidation products when T2 was dissolved in mineral oils.