Transformation Of Hydrocarbons Research Articles

Asymmetric paired oxidative and reductive catalysis enables enantioselective alkylarylation of olefins with C(sp3)−H bonds

Enantioselective transformations of hydrocarbons to three-dimensional chiral molecules remain a significant challenge in synthetic chemistry. This study uses asymmetric paired oxidative and reductive catalysis to promote the enantioselective alkylarylation of olefins through the functionalization of C(sp3)−H bonds in alkanes. This asymmetric photoelectrocatalytic approach enables the facile construction of a wide range of enantioenriched α-aryl carbonyls with excellent enantioselectivity (up to 96% ee) from readily accessible starting materials. Notably, aryl bromides, aryl iodides, and even aryl chlorides were compatible with the developed catalytic system. Mechanistic studies reveal that alkanes and electrophiles are simultaneously activated on the electrodes.

Novel insights into the factors influencing rhizosphere reactive oxygen species production and their role in polycyclic aromatic hydrocarbons transformation

Reactive oxygen species (ROS) are recognised as pivotal biogeochemical process drivers. However, the factors influencing ROS production in the rhizosphere and their role in pollutant transformation remain elusive. We investigated ROS with a focus on spatiotemporal variations in superoxide radicals (O2•−), hydrogen peroxide (H2O2), and hydroxyl radicals (•OH) in the rhizosphere of maize during root development, and elucidated the impact of environmental conditions on ROS production. In-situ visualisation by fluorescence imaging showed that ROS hotspots gradually shifted from seminal to lateral roots during maize growth, indicating that newly developed roots are the major contributors to ROS production. The three types of ROS contents changed with root growth, suggesting that root development regulates ROS production. The ROS contents reached a maximum at 25 °C and 45% maximum field capacity. Both ambient temperature and soil moisture indirectly influenced ROS production by regulating the release of root exudates to induce changes in water-soluble phenols and dissolved organic carbon (DOC). In contrast, ROS content gradually increased with oxygen availability, which directly mediated ROS generation by acting as a precursor. More interestingly, the presence of polycyclic aromatic hydrocarbons (PAHs) significantly enhanced ROS generation, which further promoted PAH removal with a contribution of 31.4–43.3%. These findings provide new insights into the occurrence, distribution, and environmental effects of ROS in the rhizosphere.

(Invited) Plasma Reforming of Liquid Hydrocarbons

Engineering systems that more sustainably use our natural resources is central to both reducing the risks associated with CO2 emissions and making the long-term transition to a more circular, sustainable, and electrified economy. In particular, developing electrically driven technologies to leverage the energy density of liquids to produce clean fuels, e.g., H2, without making CO2, could be game changing. Here, we investigate the potential of directly exciting plasmas in liquid hydrocarbons to create multi-phase reaction environments, i.e., environments where plasma (ionized gas), H2, gaseous and liquid hydrocarbons, and solid carbon are all present simultaneously, to produce H2, unsaturated C2s, and carbon. The ultimate target is direct transformation of liquid hydrocarbons to gaseous H2 and solid, easy-to-separate carbon using electricity that can be provided from any source and/or points of use.This talk will focus on our recent experiments to strike and sustain low and high frequency plasma discharges in liquid hydrocarbon jets to simultaneously generate gaseous H2, C2s, and solid carbon at high rates. Preliminary experiments show that (i) input energy is not wasted in simply vaporizing the liquid - so the system’s specific energy input preferentially drives hydrocarbon cracking; (ii) discharge drive frequency and plasma space time have a big effect on the H2 specific energy requirement (SER) and H2 generation rate, respectively; (iii) feedstock chemistry affects the H2 and C2 products observed; (iv) carbon particulates rapidly form in the liquid hydrocarbon, but they can be separated easily; and (v) the SER for H2 production is 25-30 kWhr/kg, roughly two times less than water electrolysis in practice (60 kWhr/kg). Hydrocarbon conversion, reaction rates, and characterization of the plasma (OES, high speed imaging), gas (MS), liquid (GC/MS), and solid phase (SEM, Raman) products as a function of plasma operating conditions (high and low AC drive frequency; liquid-plasma contact time) and hydrocarbon source will be discussed.

THERMAL TRANSFORMATIONS OF MALTENES AND OILS FROM HEAVY METHANE BASE CRUDES

The paper considers changes of composition of oils and maltenes during thermal cracking process. The oils and maltenes (mixture Oils+Resins) were isolated from crudes from two oil fields: Zyuzeevskoye (Republic of Tatarstan) and Zuunbayanskoye (Mongolia). Both crudes relate to methane type, but differ by content of saturated, aromatic hydrocarbons, resins, asphaltenes and sulfur. Cracking of oils and (O+R) mixtures was carried out at 450 °С for 120 min in isothermal mode. Data on the mass balance of process, composition of gaseous and liquid cracking products were obtained. It was shown the С1-С5 hydrocarbons are predominate in the composition of gaseous cracking products of oils and (O+R) mixtures. Independent of cracking object their content changes in a series: C1 > C2 > C3 > С4-С5. The dynamics of group hydrocarbon composition changes in thermolysates was studied. It was shown the thermal transformations of hydrocarbons steer in the direction of destruction reactions during cracking of oils with high content of saturated hydrocarbons, as it indicated by gaseous products yield. Condensation reactions are dominated during cracking of oils, in composition of which aromatic hydrocarbons are prevail. It was shown the addition of resins into the complex multicomponent mixture of hydrocarbons leads to directivity change of cracking free radical reaction behavior. Differences in structural-group characteristics of average resins molecules reflect not only on the yield of solid and gaseous cracking products of (O+R) mixture, but also affect on the directivity of hydrocarbons thermal transformations. Moreover it is impossible to exclude the effect of differences in the content of saturated and aromatic hydrocarbons in the composition of oils on the components thermal transformations during cracking process of (O+R) mixtures. For citation: Voronetskaya N.G., Pevneva G.S. Thermal transformations of maltenes and oils from heavy methane base crudes. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 8. P. 59-67. DOI: 10.6060/ivkkt.20246708.4t.

Hydroamination of alkenes with dinitrogen and titanium polyhydrides.

An ideal synthesis of alkyl amines would involve the direct use of abundant and easily accessible molecules such as dinitrogen (N2) and feedstock alkenes1-4. However, this ambition remains a great challenge as it is usually difficult to simultaneously activate both N2 and a simple alkene and combine them together through carbon-nitrogen (C-N) bond formation. Currently, the synthesis of alkyl amines relies on the use of ammonia produced through the Haber-Bosch process and prefunctionalized electrophilic carbon sources. Here we report the hydroamination of simple alkenes with N2 in a trititanium hydride framework, which activates both alkenes and N2, leading to selective C-N bond formation and providing the corresponding alkyl amines on further hydrogenation and protonation. Computational studies reveal key mechanistic details of N2 activation and selective C-N bond formation. This work demonstrates a strategy for the transformation of N2 and simple hydrocarbons into nitrogen-containing organic compounds mediated by a multinuclear hydride framework.

ASESSMENT OF THE EFFECTIVENESS OF CAVITATION PROCESSING OF DARK OIL PRODUCTS

The paper presents experimental results of the influence of the conditions of cavitation treatment of dark petroleum products in the hydrodynamic regime on the yield of fractions boiling up to 400 °C. Straight-run products (fuel oils, vacuum gas oils), as well as catalytic cracking gas oils, were considered as raw materials. The influence of raw material characteristics (density, fractional and group hydrocarbon composition) and its processing conditions (pressure, at five cycles of exposure) on the yield of the target fraction is considered. The linear dependence of the yield of the target fractions on the processing pressure is revealed. The constructed regression models are adequate, informative, and all their coefficients are significant. Taking into account the density of the feedstock did not improved models. The best model constructed was tested using the cross-validation method. The average forecast error was 11%, the maximum was 22%. For a small number of samples, such an error is acceptable. The possibility of assessing the effectiveness of cavitation treatment of crude oil based on data on its fractional and group hydrocarbon composition is shown. It was possible to build several regression models linking the increase in yield with pressure during processing and the content of resins and oils in the raw materials. All of them are adequate and informative, and their coefficients are significant. The increase in the yield of fractions boiling up to 400 °C is associated with the transformations of hydrocarbons during cavitation. The possibility of evaluating the effectiveness of cavitation treatment of petroleum raw materials based on data on its group hydrocarbon composition has been established. Several regression models have been constructed linking the increase in yield with the pressure during processing and the content of resins and oils in the raw materials. All of them are adequate and informative, and their coefficients are significant. Based on the constructed models, it is assumed that the change in the fractional composition of petroleum products during cavitation treatment is more associated with the destruction of the transition and solvate layers of complex structural units of the oil dispersed system than with the course of cracking reactions. For citation: Peshnev B.V., Burlyaeva E.V., Nikishin D.V., Nikolaev A.I., Kuznetsov A.S. Asessment of the effectiveness of cavitation processing of dark oil products. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 7. P. 103-110. DOI: 10.6060/ivkkt.20246707.7006.

Catalyst for moderate hydrocracking of polycyclic aromatic hydrocarbons in LCO to produce chemical raw materials: Ni in-situ modified Y zeolite-supported-NiWS

Light cycle oil is rich in polycyclic aromatic hydrocarbons with low cetane number, and the best approach is to convert them into chemical raw materials with carbon number in the range of C6-C8. In view of the above problem, Y zeolites with different Ni contents were synthesized by in-situ synthesis strategy, and corresponding NiWS supported catalysts were prepared. Taking naphthalene as the model compound, the catalytic performance of the catalysts was evaluated. The effects of Ni in-situ modification on the physicochemical properties of Y zeolite and the active phase properties of catalyst were investigated. Ni in-situ modification effectively improved the number of medium-strong B acid sites in Y zeolite and weakened the MSI of the catalyst. Appropriate Ni content had a positive effect on the dispersion and stacking number of active phase. Owed to the increased number of medium-strong B acid sites and the properties of active phase, 2J-Ni-YCat showed the best catalytic performance in the hydrocracking of naphthalene to produce C6-C8 products. It is expected to provide reference for the transformation of polycyclic aromatic hydrocarbons into high value-added C6-C8 products in petrochemical industry.

Transformation of aromatic hydrocarbons in the process of hydrogenation of a concentrated mixture to produce clean fuels

The process of hydrogenation of a modeling mixture of aromatic hydrocarbons was studied in order to develop regulated approaches for producing environmentally friendly fuels. The process was carried out on a trimetallic PdNiCr catalyst deposited on aluminum oxide. The optimal conditions for carrying out the reaction were determined. The influence of the structure of substituted substrates on the formation of by-products of the ring-opening reaction has been established.

Valorisation of low-density polythene (LDPE) waste into fuels and chemicals through alkane hydroxylase and microbial treatment

Polythene exhibits low reactivity and slow biodegradability due to its highly reduced hydrocarbon structure. In this study, a process has been developed for the transformation of polythene waste into fuel and its precursor molecule by microbial and enzymatic treatments. In first step polythene was pretreated with Paenibacillus alvei. Through fermentation process for 15 days and products released after fermentation were subsequently bio-transformed into alcohols and acids corresponding to its hydrocarbons, employing Alkane hydroxylase (AlkB). On fermentation using Paenibacillus alvei, 16.8% weight loss was observed after 15 days and surface modification was analyzed through AFM and SEM. The major products released during microbial pretreatment analyzed through Chromatography–High-Resolution Mass Spectrometry (GC-HRMS) were pentane, hexane, heptadecane, dodecane, tetracontane, bromotetradecane, methyl esters, hexadecane, etc. which were converted in second step into hexadecanol, octadecanol, octadecanoic acid, and heptadecanoic acid, etc. with the help of Alkane hydroxylase on enzymatic transformation. These findings suggested that the microbial pretreatment results in a release of alkanes, some fatty acids, and esters using Paenibacillus alvei Among these, AlkB facilitated the transformation of C16 and C15 hydrocarbons into hexadecanol, and pentadecanol respectively. This process holds the potential as an alternative to traditional fuels, and an optimization process can be pursued to enhance the overall yield.

A simple protocol for estimating the acute toxicity of unresolved polar compounds from field-weathered oils

Crude oil spilled at sea is chemically altered through environmental processes such as dissolution, biodegradation, and photodegradation. Transformation of hydrocarbons to oxygenated species increases water-solubility. Metabolites and oxidation products largely remain uncharacterized by common analytical methods but may be more bioavailable to aquatic organisms. Studies have shown that unresolved (i.e. unidentified) polar compounds (‘UPCs’) may constitute > 90% of the water-accommodated fraction (WAF) of heavily weathered crude oils, but still there is a paucity of information characterizing their toxicological significance in relation to other oil-derived toxicants. In this study, low-energy WAFs (no droplets) were generated from two field-weathered oils (collected during the 2010 Deepwater Horizon incident) and their polar fractions were isolated through fractionation. To allow establishment of thresholds for acute toxicity (LC50) of the dissolved and polar fraction of field collected oils, we concentrated both WAFs and polar fractions to beyond field-documented concentrations, and the acute toxicity of both to the marine copepod Acartia tonsa was measured and compared to the toxicity of the native WAF (non-concentrated). The difference in toxic units (TUs) between the total of the mixture and of identified compounds of known toxicity (polycyclic aromatic hydrocarbons [PAHs] and alkyl phenols) in both WAF and polar fractions was used to estimate the contribution of the UPC to overall toxicity. This approach identified that UPC had a similar contribution to toxicity as identified compounds within the WAFs of the field-weathered oils. This signifies the relative importance of polar compounds when assessing environmental impacts of spilled and weathered oil.

Elucidating the significant roles of root exudates in organic pollutant biotransformation within the rhizosphere

Biotransformation of organic pollutants is crucial for the dissipation of environmental pollutants. While the roles of microorganisms have been extensively studied, the significant contribution of various root exudates are still not very well understood. Through plant growth experiment, coupled with gas and liquid chromatography-mass spectrometry methods, this study examined the effect of the presence of M. sativa on microbial-associated biochemical transformation of petroleum hydrocarbons. The results of this study revealed that the concentration of exudates within the soil matrix is a function of proximity to root surfaces. Similarly, biodegradation was found to correlate with distance from roots, ranging from ≥ 90% within the rhizosphere to < 50% in bulk soil and unplanted control soil. Most importantly, for the first time in a study of an entire petroleum distillate, this study revealed a statistically significant negative correlation between root exudate concentration and residual total petroleum hydrocarbons. While not all the compounds that may influence biodegradation are derived from roots, the results of this study show that the presence of plant can significantly influence biodegradation of hydrocarbon pollutants through such root exudation as organic acids, amino acids, soluble sugars and terpenoids. Therefore, root exudates, including secondary metabolites, offer great prospects for biotechnological applications in the remediation of organic pollutants, including recalcitrant ones.

New insights for valorization of polyolefins/light alkanes: catalytic dehydrogenation of n-alkanes by immobilized pincer-iridium complexes.

This scientific review delves into the innovative realm of polyolefins/light alkanes valorization through their catalytic dehydrogenation employing pincer-ligated iridium organometallic complexes. These widely studied catalysts exhibit outstanding properties, although the intrinsic characteristics of homogeneous catalysis (such as challenging product-catalyst separation, poor applicability to continuous-flow processes and low recyclability) limit their activity and industrial application, as well as their thermal stability. Through the immobilization of complexes on inorganic supports, these downsides have been bypassed, harnessing the true potential of these catalysts, affording more selective and stable catalysts in addition to facilitating their implementation in industrial processes. The findings described herein contribute to the advancement in the understanding of catalytic processes in hydrocarbon transformations, offering promising avenues for sustainable and selective production of valuable chemical intermediates from readily available feedstocks.

The implication of kinetics characteristics of modern organisms for the hydrocarbon generation evolution of organic matter components in the lacustrine source rocks: A case study of the Dongying Formation from the Bozhong Sag, Bohai Bay Basin

The hydrocarbon generation evolution characteristics of lacustrine source rocks are crucial for understanding hydrocarbon resources. In this research, we focus on the mudstone found in the third member of the Paleogene Dongying Formation (E3d3) within the Bozhong Sag of the Bohai Bay Basin as a case study. An analysis of the discrepancy in geochemical characteristics and kinetic parameters was carried out by utilizing the modern organisms (pine pollen and benthic algae) analogies to the organic matter (OM) components (Pinaceae sporopollen and benthic algae amorphous). Furthermore, the bulk hydrocarbon evolution of the Dongying Formation mudstones was further discussed in combination with a water-added sealing thermal simulation experiment and basin simulation. Our findings indicate that the pine pollen and benthic algae have higher OM abundance compared to the E3d3 mudstones, and their OM types are both Ⅱ1-Ⅱ2, which possess excellent potential for oil generation. In contrast, the E3d3 mudstones are predominantly in the low mature to mature thermal evolution stage. When we compare hydrocarbon generation rates and transformation ratios using Rock-Eval pyrolysis, it becomes evident that modern organisms are more prone to generate large amounts of hydrocarbons even at a low mature stage. The kinetic parameters of pine pollen are notably higher compared to those of benthic algae and the E3d3 mudstone samples. In parallel first-order reactions, the activation energy obtained by the single-frequency factor model (SFFP model) displays a narrow distribution range, while the activation energy distribution range of the multi-frequency factor model (MFFP model) is broader. The MFFP model focuses more on the variations of hydrocarbon kinetic parameters throughout the entire process, which is more in conformity with the actual geological process. The enclosed thermal simulation experiment and basin simulation analysis unveil the presence of two distinct phases of hydrocarbon generation within the Dongying Formation. Furthermore, it becomes evident that abundant benthic algae and Pinaceae sporopollen components play vital roles in both of these phases. In conclusion, the method of applying modern organisms to analogize the hydrocarbon generation evolution characteristics of the parent components of lacustrine source rocks seems feasible. Meanwhile, the Dongying Formation in the Bozhong Sag also possesses broad exploration prospects for hydrocarbon resources.

Hydrocarbon Transformations in Bottom Sediments after an Emergency Spill of Diesel Fuel in Norilsk

Hydrocarbon Transformations in Bottom Sediments after an Emergency Spill of Diesel Fuel in Norilsk

Enrichment of Aerobic and Anaerobic Hydrocarbon-Degrading Bacteria from Multicontaminated Marine Sediment in Mar Piccolo Site (Taranto, Italy).

Marine sediments act as a sink for the accumulation of various organic contaminants such as polychlorobiphenyls (PCBs). These contaminants affect the composition and activity of microbial communities, particularly favoring those capable of thriving from their biodegradation and biotransformation under favorable conditions. Hence, contaminated environments represent a valuable biological resource for the exploration and cultivation of microorganisms with bioremediation potential. In this study, we successfully cultivated microbial consortia with the capacity for PCB removal under both aerobic and anaerobic conditions. The source of these consortia was a multicontaminated marine sediment collected from the Mar Piccolo (Taranto, Italy), one of Europe's most heavily polluted sites. High-throughput sequencing was employed to investigate the dynamics of the bacterial community of the marine sediment sample, revealing distinct and divergent selection patterns depending on the imposed reductive or oxidative conditions. The aerobic incubation resulted in the rapid selection of bacteria specialized in oxidative pathways for hydrocarbon transformation, leading to the isolation of Marinobacter salinus and Rhodococcus cerastii species, also known for their involvement in aerobic polycyclic aromatic hydrocarbons (PAHs) transformation. On the other hand, anaerobic incubation facilitated the selection of dechlorinating species, including Dehalococcoides mccartyi, involved in PCB reduction. This study significantly contributes to our understanding of the diversity, dynamics, and adaptation of the bacterial community in the hydrocarbon-contaminated marine sediment from one sampling point of the Mar Piccolo basin, particularly in response to stressful conditions. Furthermore, the establishment of consortia with biodegradation and biotransformation capabilities represents a substantial advancement in addressing the challenge of restoring polluted sites, including marine sediments, thus contributing to expanding the toolkit for effective bioremediation strategies.

Generation and expulsion of Lower Jurassic hydrocarbon in different source rocks in the Taibei Sag, Turpan-Hami Basin, northwest China

Source rocks in the first (J1s1) and second (J1s2) members of the Lower Jurassic Sangonghe Formation (J1s) in the Taibei Sag, Turpan-Hami Basin, NW China, are shore-shallow lacustrine mudstone and semi-deep to deep lacustrine mudstone. These two sets of mudstones provide an excellent opportunity for investigating the origin and expulsion patterns of hydrocarbon from source rocks under different environments. Through systematic geochemical analysis, including total organic carbon (TOC), Rock-Eval analysis, GC-MS analysis, and major and trace element analysis, the geochemical characteristics and sedimentary environment of the Sangonghe Formation (J1s) source rocks were evaluated. By integrating kerogen kinetics modeling, a more precise assessment of the hydrocarbon generation and expulsion characteristics of the source rocks from both members of the Sangonghe Formation is achieved. The fine-grained sediments of the Sangonghe Formation were formed in a weakly oxidized brackish water body. The J1s1 mudstone was deposited in a shore-shallow lacustrine environment. The repeated river influx increased the input of terrestrial higher plants, which complicated the maceral composition and diluted the abundance of organic matter. The J1s2 source rocks were formed in the semi-deep to deep lacustrine environment during the maximum transgression period with a large thickness and high TOC values, the maceral composition was dominated by a mixed source of aquatic organisms and terrestrial plants. Consequently, the source rocks of J1s2 exhibit higher initial hydrogen index (HI0), hydrocarbon generation potential (Qg) and transformation ratio (Tr) compared to those of the J1s1 source rocks, while the interbedded mudstone with limited thickness in J1s1 exhibits a higher hydrocarbon expulsion efficiency (Re).

Atom Transfer Radical Coupling Enables Highly Enantioselective Carbo-Oxygenation of Alkenes with Hydrocarbons.

The selective functionalization of C(sp3)-H bonds has emerged as a transformative approach for streamlining synthetic routes, offering remarkable efficiency in the preparation and modification of complex organic molecules. However, the direct enantioselective transformation of hydrocarbons to medicinally valuable chiral molecules remains a significant challenge that has yet to be addressed. In this study, we adopt an atom transfer radical coupling (ATRC) strategy to achieve the asymmetric functionalization of C(sp3)-H bonds in hydrocarbons. This approach involves intermolecular H atom transfer (HAT) between a hydrocarbon and an alkoxy radical, leading to the formation of a carbon-centered radical. The resulting radical adds to alkenes, generating a new radical species that is intercepted by a chiral copper-mediated C-O bond coupling. By employing this method, we can directly access valuable chiral lactones bearing a quaternary stereocenter with high efficiency and excellent enantioselectivity. Importantly, ATRC exhibits great potential as a versatile platform for achieving stereoselective transformations of hydrocarbons.

Radiation-induced isomerization reaction mechanism of hydrocarbons on the surface of solid acid

This paper's goal is to investigate how petroleum's n-alkane isomerization reaction occurs on the surface of a solid nanocatalyst. In this experiment, the isomerization of aromatic-rich crude oil is being studied as a result of radiation exposure. It was discovered that sodium-rich bentonite –solid acid, from the Alpoid deposit works well as a catalyst for refining petroleum. Possible mechanisms of the radio-catalytic reaction that converts n-alkanes to branched hydrocarbons have been researched by methods of FT- IR spectroscopy and gas chromatography. The effect of acidity type of the nanostructured bentonite clay on Lewis acid cites is proposed to explain observed results. Additional radiation energy, which is mainly generated due to the nanobentonite volume, results in a more efficient aromatic- rich petroleum radiolysis process. Also, it was investigated the dynamics of dose –dependent changes in the amount of branched hydrocarbons. One of the primary objectives of this research work is increasing the efficiency of transformation of adsorbed beam energy in solid phase to the system and improvement of hydrocarbon isomerization reactions in crude oil. The results of hydrocarbon transformations are discussed in terms of the behavior of excited electrons in solids. Novel eco-friendly nanocatalyst creates new opportunities for hydrocarbons with multi- branched structures.

Influences and mechanisms of pyrolytic conditions on recycling BTX products from passenger car waste tires

Pyrolysis is an effective method for waste tire disposal. However, it has rarely been used to recycle specific highly valuable components (such as benzene, toluene, and xylene (BTX)) from tire rubbers, owing to complicated pyrolytic reactions. This study investigated the pyrolysis process of passenger-car-waste-tires (PCWT) with the help of TG–DTG and Py–GC/MS. Based on response surface methodology (RSM), the effect of pyrolytic parameters on the yields of pyrolytic oil and BTX is evaluated. Furthermore, the BTX generation mechanisms are discussed from the perspective of aliphatic and aromatic hydrocarbon transformations. Additionally, pyrolytic conditions including temperature, rubber particle size, pressure, and gas flow rate were systemically investigated and the optimum pyrolytic condition for yield of BTX (26.5 g per 100 g tire rubber) was obtained [765 K, 0.7 mm, 0.52 MPa and 2.5 mL (g min)−1]. Therein, yield of benzene, toluene and xylene were 1.07, 5.03 and 20.40 g per 100 g tire rubber, respectively. During PCWT pyrolysis, BTX is primarily obtained via the Diels–Alder reactions of small-chain alkenes and transformations of limonene and aromatics. This study elucidates the BTX generation mechanisms during PCWT pyrolysis and clarifies the effects of varying pyrolytic conditions on BTX generation.

Synthesis of Triamantane by Skeletal Transformation of Hexa- and Heptacyclooctadecanes under the Action of Ionic Liquids

abstract: New methods have been developed for the synthesis of the third representative of the homologous series of diamond-like hydrocarbons, triamantane, with a yield of up to 78%, by skeletal isomerization of iso-compositional endo-endo- and exo-exo-heptacyclo [9.6.1.02,10.03,8.04,6.05,9.012,17]octadecanes under the action of aluminate ionic liquids. For the first time, the synthesis and transformation of new C18H26 hydrocarbons - endo-exo- and exoexo- hexacyclo[8.6.1.15,8.02,9.03,7.011,16]octadecanes into triamantane was carried out. It has been established that for the successful conversion of polycyclic hydrocarbons of the composition С18H26 containing two more hydrogen atoms in the molecule than in triamantane, the addition of Pd/C to the ionic liquid is necessary.