High Molecular Hydrocarbons Research Articles

Pyrolysis of Heavy Hydrocarbons Under Microwave Heating of Catalysts and Adsorbents

The main features of high temperature chemical reactions under microwave (MW) heating have been considered. The efficiency of the MW power to heat conversion in a MW cavity is estimated, theoretically and experimentally, for different substances and conditions. The new approaches for MW processing of high-molecular hydrocarbons are proposed: (i) thermal decomposition in contact with microwave absorbing catalyst particles placed into liquid substrate; (ii) cracking of hydrocarbons pre-absorbed inside porous granules under rapid MW heating of adsorbent. It has been experimentally found that these approaches provide non-traditional conditions of reaction and can lead to the formation of valuable chemical products.

Nonlinear compensation effect of dynamic viscosity of multicomponent hydrocarbon systems

A nonlinear compensation effect determining the dependence of the energy of a flow of a Newtonian liquid on the preexponent of its viscosity was detected. Empirical dependences relating the softening temperature of a Newtonian high-molecular multicomponent hydrocarbon system with the activation energy of its viscous flow have been obtained. The results obtained are supported by the statistical data and allow one to predict the dynamic viscosity of oil and coal fractions and materials based on them.

Detection of electrically charged soot particles in laminar premixed flames

A particle mass spectrometer has been used to investigate the formation of electrically charged species and soot particles in laminar premixed flames. The mass range was from 600–6 × 10 5 amu and extends from high molecular hydrocarbons to soot particles of 10 nm diameter. The flames were stabilized on cooled porous plate burners. Acetylene/oxygen flames were investigated at low pressure (30 mbar), and ethylene/air flames were investigated at atmospheric pressure. Soot particles could only be detected in flames showing yellow luminosity, i.e. above the critical C/O-ratio for soot formation. Both positively and negatively charged particles were found, the positive charge dominating in the low pressure acetylene/oxygen flames, the negative charge dominating in the atmospheric ethylene/air flames. With the assumption of spherical shape and constant density, the mass spectra were converted to size spectra. Usually, they show a multiple peak structure which is somewhat difficult to interpret. There are indications that particles may carry multiple (1–2) charges, and also that particles of different types may coexist beside polyaromatic and polyhedral species in the early stage of particle inception.

Horizontal Transfer of PAH Catabolism Genes in Mycobacterium: Evidence from Comparative Genomics and Isolated Pyrene-Degrading Bacteria

Biodegradation of high molecular weight polycyclic aromatic hydrocarbons (PAHs), such as pyrene and benzo[a]pyrene, has only been observed in a few genera, namely fast-growing Mycobacterium and Rhodococcus. In M. vanbaalenii PYR-1, multiple aromatic ring hydroxylating dioxygenase (ARHDOs) genes including pyrene dioxygenases nidAB and nidA3B3 are localized in one genomic region. Here we examine the homologous genomic regions in four other PAH-degrading Mycobacterium (strains JLS, KMS, and MCS, and M. gilvum PYR-GCK), presenting evidence for past horizontal gene transfer events. Seven distinct types of ARHDO genes are present in all five genomes, and display conserved syntenic architecture with respect to gene order, orientation, and association with other genes. Duplications and putative integrase and transposase genes suggest past gene shuffling. To corroborate these observations, pyrene-degrading strains were isolated from two PAH-contaminated sediments: Chattanooga Creek (Tennessee) and Lake Erie (western basin). Some were related to fast-growing Mycobacterium spp. and carried both nidA and nidA3 genes. Other isolates belonged to Microbacteriaceae and Intrasporangiaceae presenting the first evidence of pyrene degradation in these families. These isolates had nidA (and some, nidA3) genes that were homologous to Mycobacterial ARHDO genes, suggesting that horizontal gene transfer events have occurred.

Co-metabolic degradation of pyrene by indigenous white-rot fungus Pseudotrametes gibbosa from the northeast China

Pyrene as high molecular weight polycyclic aromatic hydrocarbons (PAHs) is found in most terrestrial environment. However, the biodegradation of pyrene has been limited due to its bioavailability and toxicity. So it is vital to study degradation-capable microorganism and suitable co-substrate. In this study, the indigenous white-rot fungus Pseudotrametes gibbosa isolated from ChangBai Mountain located in northeast China was used to degrade pyrene, and 6 co-substrates were selected as co-metabolic carbon and energy sources. The results showed that P. gibbosa was able to utilize pyrene as sole carbon and energy source. The degradation efficiency achieved 28.33% within 18 days. Meanwhile, co-substrate wheat bran extract could stimulate laccase (Lac) production significantly by P. gibbosa, compared with other co-substrates and control (without co-substrate). In the presence of co-substrates, the biodegradation efficiency of pyrene ranged from 34.23% to 50.64% which was enhanced due to co-metabolism except for salicylic acid (25.91%) and phthalic acid (21.64%).

Biomarker responses and disease susceptibility in juvenile rainbow trout Oncorhynchus mykiss fed a high molecular weight PAH mixture

Juvenile rainbow trout were fed a diet containing an environmentally relevant mixture of 10 high molecular weight polycyclic aromatic hydrocarbons (PAHs) at a dose of 0.66 or 7.82 µg PAH · g fish(-1) · d(-1). At 3, 7, 14, and 28 d, biomarkers of aryl hydrocarbon receptor activation (AHR), hepatic microsomal ethoxyresorufin-O-deethylase (EROD) activity, and cytochrome P4501A (CYP1A)-associated staining increased 14- to 26-fold and 6- to 14-fold, respectively, in fish fed 7.82 µg PAH · g fish (-1) · d(-1). Cytochrome P4501A-associated staining increased 2- to 9-fold on days 3, 7, and 28 in fish fed 0.66 µg PAH · g fish(-1) · d(-1). Bile fluorescent aromatic compounds served as a biomarker of exposure and confirmed that PAH exposure was consistent over 50 d. DNA damage in blood cells, protein oxidation, and lipid peroxidation in the kidney were biomarkers of oxidative stress and all increased in fish fed 7.82 µg PAH · g fish(-1) · d(-1). Fish fed 0.66 µg PAH · g fish(-1) · d(-1) had elevated DNA damage in blood cells but increased protein oxidation or lipid peroxidation in the kidney were not observed. Challenge with Aeromonas salmonicida, at lethal concentration (LC) 20, decreased survival in fish previously fed either 0.66 µg PAH · g fish(-1) · d(-1) or 7.82 µg PAH · g fish(-1) · d(-1) relative to fish fed the control diet. In general, biomarkers of both AHR activation and oxidative stress peaked at 3 to 14 d then declined at 28 to 50 d of PAH exposure and an increase in susceptibility to disease was observed at 50 d. These results link PAH exposure to biomarker responses that may be useful as early indicators of population level responses, such as mortality resulting from an increase in disease susceptibility.

Solid phase extraction cleanup for non-polar and moderately polar molecular markers of PM 2.5 sources

A solid phase extraction cleanup step substantially improved analytical efficiency and data quality for measurements of non-polar and moderately polar organic molecular marker concentrations in airborne particulate matter. Rapid gas chromatography column deterioration was evident after very few samples in the absence of a cleanup step, resulting in the need for frequent recalibration. High molecular weight polycyclic aromatic hydrocarbons, were among the species most strongly impacted by the deterioration, exhibiting deviations as high as 30–40% from expected calibration verification standard values after only a few injections. Column deterioration and calibration verification failure were eliminated by introducing a solid phase extraction step prior to analysis and a total of 58 samples were analyzed with no unacceptable deviation of calibration verification standards from target values

Mixture of High Molecular Weight Polycyclic Aromatic Hydrocarbons Biodegradation by Tropical Bacteria and via Co-Metabolism with Phenanthrene

Mixture of High Molecular Weight Polycyclic Aromatic Hydrocarbons Biodegradation by Tropical Bacteria and via Co-Metabolism with Phenanthrene

Scientific foundations of preparation and technologies of production of the catalysts of reforming of gasoline fractions: Development of the process technology

The article summarizes the results of development of the scientific foundations of preparation of the catalysts, and of the experimental development works on creation of the new technologies of their production with the use of physical models, which were previously created on the basis of fundamental research. The results of the adoption of the new production technologies of the reforming catalysts of the PR series at the domestic plants are presented. The adoption consisted in creation and approbation of the fundamentally new technologies of production of the aluminum hydroxide (AHO) by means of the continuous method, modification of AHO by the elements of IV group, plasticization and forming of AHO in the production of the support, application of H2PtCl6 using the reactions of the ligand substitution of C− by the functional groups of the support, and reduction and activation of the catalyst, which provide the optimal chemical com- position. Their operation during the 15-year period is analyzed. The reasons of high selectivity (up to 90%) of the new catalysts are found; the new technologies of the combined processing of mixture of C3-C4 alkanes with C5+ are developed and tested for the production of the high-octane catalysts with selectivity approaching 100%. The main effect of the C5+ yield increase of the end products is achieved by the transformation of the C3-C4 alkanes into the more high-molecular aromatic hydrocarbons. New processes of the combined processing of the mixtures of C3-C4 and gasoline fractions can be considered to be an alternative technology, which solves the important task of broadening the source of raw materials of the motor fuels by the inclusion of the C3-C4 alkanes of little value into the processing.

High Molecular Weight Polycyclic Aromatic Hydrocarbons Biodegradation by Bacteria Isolated from Contaminated Soils in Nigeria

High Molecular Weight Polycyclic Aromatic Hydrocarbons Biodegradation by Bacteria Isolated from Contaminated Soils in Nigeria

Thermodynamic calculations in the Fe–O–C–H system and decomposition–reduction of iron oxalate in a complex gas medium

A thermodynamic calculation is performed for processes occurring in the Fe-O-C-H system during decomposition-reduction of iron oxalate in a gaseous medium formed in the thermal destruction of high-molecular hydrocarbons. This makes it possible to choose optimal temperature conditions and ratios of components for obtaining magnetic iron-based powders for medicine with required phase composition. It is shown that, under the actual kinetic experimental conditions, the products of decomposition-reduction of iron oxalate in a complex gaseous medium are thermodynamically favored phases.

Microbiological estimate of water quality in the Amur and Sungari rivers after a technogenic accident in China in 2005

The results of microbiological water quality monitoring in the Amur and Sungary rivers after a tech- nogenic accident in Tzilin province (China) in November 2005 are considered. Bioindication technique is used to show that various pollutants earlier entered the Amur with the Sungari runoff: low-molecular volatile ben- zene derivatives entered from November 28 to December 2; naphthalene derivatives entered from November 29 to December 7; and nitrobenzene and high-molecular polyaromatic hydrocarbons entered in December 15-23, 2005. The major portion of pollutants moved along the right bank. The most sensitive to the total pollution by toxic substances were nitrifying bacteria, especially in bottom water layers. The Amur water in the zone of influence of the Sungari was estimated to belong to the IV-V quality class and referred to the categories of "pol- luted" and "dirty." The poor quality of Amur water persisted over 9 months throughout the Amur reach from the Sungari mouth to Khabarovsk City.

Tendencies in the distribution and hypotheses of the genesis of condensed naphthides in magmatic rocks from various geodynamic environments

Literature data suggest that concentrated naphthides (CN)—bitumen and oil—can occur in intrusive and volcanic rocks of various silicity and alkalinity whose age ranges from the Proterozoic to Recent. The qualitative composition of heavy (high-molecular) hydrocarbons (HHC) in CN is the same in various rocks: heavy alkanes, polycyclic aromatic hydrocarbons (PAH), oxygen-bearing derivatives of hydrocarbons, etc. The presence of CN in rock-forming minerals in magmatic rocks and pegmatites confirms that CN condensed during the epimagmatic stage, and the molecular mass of the CN, for example, in the Khibina alkaline massif decreased with decreasing temperature simultaneously with the evolution of its mineral assemblages. The synthesis of CN continues during the hydrothermal stage, but high-temperature associations of HHC gave way during this stage to low-temperature ones. During all evolutionary stages of magmatic and related processes, the contents of CN are correlated with those of trace elements, which likely occur as organoelement compounds (OEC). Hypotheses of endogenic and exogenic genesis of CN in magmatic rocks are discussed. The endogenic hypotheses include HHC synthesis from inorganic gases and light hydrocarbons (HC) on catalytic minerals. The fact that HHC and CN occur in mantle xenoliths and high-pressure minerals and the results of experimental and thermodynamic modeling are discussed as supporting the hypothesis of the mantle genesis of CN in magmatic rocks. The metastable ascent of gaseous HHC, the low oxygen fugacity, and the high alkalinity of the melts could be favorable for the partial preservation of HHC in these rocks at crustal depth levels. Endogenic CN can serve as a nutrient medium for microorganisms in the upper lithosphere. Exogenic hypotheses for the genesis of HHC in magmatic rocks assume that the melts should have assimilated sedimentary rocks rich in organic matter and that biogenic oil could be transported from sedimentary reservoirs to magmatic rocks. An important role in determining the genesis of CN in magmatic rocks is played by endogenic and biogenic markers.

On the probable lifting of deep hydrocarbons into the crustal waveguide

The equilibrium thermodynamic calculations made for C-H and C-H-N-O-S systems show that the mantle might contain a fluid consisting of heavy (high-molecular) hydrocarbons (HHC) and their derivatives, as well as of inorganic gases (H2O, CO2, N2, NH4, H2S, etc.). In the range of diamond-graphite phase transition, the HHC are decomposed to form methane, its nearest homologues, and graphite. The geochemical and experimental data by different authors point to possible HHC occurrence in the upper mantle. These results confirm the concept by Dmitrievskii (2006) that the deep fluids might be lifted to the crustal waveguide to fill its fractures and cavities. Owing to compaction, the fluids are squeezed from the waveguide and lifted into sedimentary layers to form the commercial hydrocarbon deposits. Resulting from the “washing“ of sedimentary rocks with the fluids, hydrocarbon gases and oil of organic origin might be formed.

Вплив гербіцидної обробки Ambrosia artemisifolia на склад поверхневих восків рослин наступної генерації

У вегетаційному експерименті досліджено особливості складу вуглеводнів поверхневих восків листя рослин наступної генерації, вирощених із насіння, зібраного на контрольних і оброблених гербіцидами рослинах амброзії полинолистої. Встановлено суттєве зростання вмісту високомолекулярних компонентів і зниження вмісту низькомолекулярних компонентів вуглеводнів. Виявлено залежність змін складу вуглеводнів від впливу певних гербіцидів або їх комбінацій. Зроблено припущення про посилення захисних властивостей поверхневих восків ювенільних рослин амброзії через виявлені зміни.

Fenton degradation assisted by cyclodextrins of a high molecular weight polycyclic aromatic hydrocarbon benzo[a]pyrene

This paper investigates the effect of native β-cyclodextrin (β-CD) and its CD derivatives, such as hydroxypropyl-β-cyclodextrin (HPBCD) and randomly methylated-β-cyclodextrin (RAMEB), on the solubilization of a high molecular weight polycyclic aromatic hydrocarbon benzo[a]pyrene (BaP) and on its degradation by Fenton's reaction. The results show that BaP apparent solubility was significantly increased in the presence of cyclodextrin (CD) in the following order: β-CD < RAMEB < HPCD. BaP Fenton degradation was strongly dependent on the capacity of cyclodextrin to solubilize BaP. In the presence of a radical scavenger (mannitol), BaP Fenton degradation was inhibited with RAMEB but not in the presence of HPCD. Molecular modelisation was used to visualize the steric complementarity of these host-guest systems. No significant difference of encapsulation between the two modified CDs was observed. Nevertheless, the results suggest a probable existence of a ternary complex HPCD–BaP–iron permitting the generation of hydroxyl radicals in close proximity to BaP. On the basis of these results, it appears that HPCD may be useful for developing targeted BaP degradation system.

Benzo[a]pyrene degradation using simultaneously combined chemical oxidation, biotreatment with Fusarium solani and cyclodextrins

The interest of simultaneously combining chemical (Fenton’s reaction) and biological treatments for the degradation of a high molecular weight polycyclic aromatic hydrocarbon benzo[a]pyrene (BaP) has been studied in laboratory tests. An optimal concentration of 1.5 × 10 −3 M H 2O 2 as Fenton’s reagent was firstly determined as being compatible with the growth of Fusarium solani, the Deuteromycete fungus used in the biodegradation process. For the enhancement of BaP solubilisation, cyclodextrins were also used in the performed tests. The best degradation performance was achieved through the use of 5 × 10 −3 M hydroxypropyl-β-cyclodextrin (HPBCD) in comparison with randomly methylated-β-cyclodextrin (RAMEB). When Fenton’s treatment was combined with biodegradation, a beneficial effect on BaP degradation (25%) was obtained in comparison with biodegradation alone (8%) or with chemical oxidation alone (16%) in the presence of HPBCD for 12 days of incubation.

PHOTOCATALYTIC DEGRADATION OF PYRENE IN POROUS Pt/TiO2–SiO2 PHOTOCATALYST SUSPENSION UNDER UV IRRADIATION

Pyrene is a high molecular weight polycyclic aromatic hydrocarbon (PAH) that is found in water systems worldwide. It is harmful to living organisms, even when taken in very small amounts. The photocatalytic degradation of pyrene in porous Pt / TiO 2– SiO 2 photocatalyst (PPtPC) suspension under UV irradiation was investigated in this study. PPtPC was prepared by a simple heat treatment of the compacted powder mixtures of anatase TiO 2 and amorphous SiO 2 with camphor as a pore directing template, followed by coating platinum by the dip-coating method. X-ray diffraction (XRD), scanning electron microscopy (SEM) with an integrated energy-dispersive analysis of the X-ray (EDX) system, and Brunauer–Emmett–Teller (BET) were used to characterize PPtPC. The degradation kinetics of pyrene in different experimental conditions, such as initial concentration of pyrene, oxygen concentrations, pH, and temperature, were investigated. The durability of PPtPC was also tested. The results indicate that the structure of TiO 2 in PPtPC is anatase. The aggregated size of PPtPC is in the range of 10–100 μm, the mean pore diameter is 3 nm, and the BET surface area is 109 m2 g-1. The photocatalytic degradation process of pyrene follows pseudo-first-order kinetics. The rate constants increase as the initial concentration of pyrene and pH decrease. Higher temperature slightly enhances the rate constant. The dissolved oxygen in the photocatalytic degradation process is not as important as in the photolysis process. The recovered PPtPC still shows high photoactivity. This work suggests that PPtPC offers a promising method for high molecular weight PAH removal.

Investigation of Producing Modern Base Oils

Modern lube oils are prepared from base oils (base oil mixtures) and additives. The allotted quality parameters and the proper application properties are assured by the harmonical integration of these components. Some key lube oil properties depend on the quality of the base oil. For example a new demand has raised in the area of engine oils in the last couple of years: the demand is to contribute to the lower emission of the vehicles. This means the development of engine oils with low sulphated ash, low metal, sulphur and phosphorous content (“low SAPS” engine oils). In order to reach the adequate properties, the base oil (which is the main component of the engine oils) has to be produced with modern and advanced processes. The conventional base oil production line has its own disadvantages and limitations, so the catalytic processes were spread to enhance the viscosity index and to reduce the pour point of the base oils. It was necessary to develop and apply base oil production processes and technologies which are flexible to the crude oil quality and can produce environmentally friendly base oils with high viscosity index. To reach these goals the most adequate technologies are the catalytic base oil production processes. In the experimental section of this paper the results of hydroisomerization of wax from Hungarian crude oil on Pt/zeolite/Al2O3 catalyst are presented. Based on our experiments we established that with hydroisomerization base oils with very high or extra high viscosity index and low pour point can be produced from high molecular weight paraffinic hydrocarbon mixture. These base oils with low sulphur and aromatic content are appropriate, for example to produce energy efficient and environmentally friendly engine oils.

Biodegradation of Fluoranthene by Basidiomycetes Fungal Isolate Pleurotus Ostreatus HP-1

The biodegradation of fluoranthene, a high molecular weight polycyclic aromatic hydrocarbon (PAH), was investigated in submerged culture using the wood decaying fungus isolated from forest locality in Gujarat, India. The basidiomycete fungal isolate was found to have an ability to grow on sabaroud dextrose agar containing 50 mgl(-1) of each naphthalene, anthracene, acenaphthene, benzo (a) anthracene, pyrene, flouranthene, carbazole, and biphenyl. The involvement of extracellular fungal peroxidases such as manganese peroxidase (MnP) and laccase (Phenol oxidase) in the degradation of fluoranthene was studied. On the eighth day of incubation 54.09% of 70 mg l(-1) fluoranthene was removed. There after no PAHs removal was observed till the 20th day of the incubation period. The isolate was identified as Pleurotus ostreatus by 18S rRNA, 5.8S rRNA, and partial 28S rRNA gene sequencing. To the best of our knowledge this is the first time Pleurotus ostreatus have been reported to degrade such a high concentration of fluoranthene within much lower time period of incubation. Depletion in the residual fluoranthene in the culture medium was determined by HPLC. Attempts were made to identify the degradation product in the culture medium with the help of FT-IR, NMR, and HPTLC analysis. In the present study positive correlation between fluoranthene degradation and the ligninolytic enzyme (MnP and laccase) production is observed, thus this isolate can play an effective role for bioremediation of PAHs contaminated sites.