Showing papers on "Hydrocarbon published in 2018"
TL;DR: The development of photocatalytic C–H amination, alkylation, and arylation of methane, ethane, and higher alkanes under visible light irradiation at ambient temperature is reported.
Abstract: With the recent soaring production of natural gas, the use of methane and other light hydrocarbon feedstocks as starting materials in synthetic transformations is becoming increasingly economically attractive, although it remains chemically challenging. We report the development of photocatalytic C-H amination, alkylation, and arylation of methane, ethane, and higher alkanes under visible light irradiation at ambient temperature. High catalytic efficiency (turnover numbers up to 2900 for methane and 9700 for ethane) and selectivity were achieved using abundant, inexpensive cerium salts as photocatalysts. Ligand-to-metal charge transfer excitation generated alkoxy radicals from simple alcohols that in turn acted as hydrogen atom transfer catalysts. The mixed-phase gas/liquid reaction was adapted to continuous flow, enabling the efficient use of gaseous feedstocks in scalable photocatalytic transformations.
381 citations
TL;DR: In this paper, the plastic derived oil (PDO) samples obtained at low temperature pyrolysis are lighter with low viscosity, high octane number and having high calorific values.
Abstract: Low and high-density polyethylene (LDPE and HDPE) and polypropylene (PP) are three most common polyolefins profusely used as packaging materials and abundantly found in the plastic waste stream. These plastic waste samples were collected from household waste and converted into plastic derived oil (PDO) by low temperature (300 °C to 400 °C) slow pyrolysis (long isothermal holding time) in a semi-batch reactor. The PDO samples obtained had shown variation in their compositions and fuel properties based on the pyrolysis temperature. PDO from the pyrolysis of PP has high octane number (∼92) and low viscosity. Noticeably, the PDO samples obtained at low temperature pyrolysis are lighter with low viscosity, high octane number and having high calorific values. 1H NMR analysis revealed that the oil samples mostly consist of paraffinic and olefinic hydrocarbons. Simulated distillation (SimDist) of PDO indicated that the liquid products resemble the characteristic closer to middle distillate of petroleum fraction having very low pour point and flash point. The temperature with long pyrolysis time also influenced the evolved gas composition and yield. Trace amount of hydrogen, carbon monoxide and carbon dioxide were present in the gaseous product along with various hydrocarbon gases ranging from C1–C5. The degradation mechanism follows end chain scission which produces monomer units whereas random scission results most of the hydrocarbon products. Subsequent reactions like radical recombination and inter or intra molecular hydrogen transfer results in the formation of most of the olefinic components.
166 citations
TL;DR: A dual-catalyst bed of CaO and HZSM-5 was developed to convert acids in the pyrolytic products of xylan to valuable hydrocarbons and showed that CaO could effectively transform acids into ketones.
126 citations
TL;DR: Non‐oxidative dehydroaromatization of methane (MDA) is shown to be governed by a hydrocarbon pool mechanism in which benzene is derived from secondary reactions of confined polyaromatic carbon species with the initial products of methane activation.
Abstract: Non-oxidative dehydroaromatization of methane (MDA) is a promising catalytic process for direct valorization of natural gas to liquid hydrocarbons. The application of this reaction in practical technology is hindered by a lack of understanding about the mechanism and nature of the active sites in benchmark zeolite-based Mo/ZSM-5 catalysts, which precludes the solution of problems such as rapid catalyst deactivation. By applying spectroscopy and microscopy, it is shown that the active centers in Mo/ZSM-5 are partially reduced single-atom Mo sites stabilized by the zeolite framework. By combining a pulse reaction technique with isotope labeling of methane, MDA is shown to be governed by a hydrocarbon pool mechanism in which benzene is derived from secondary reactions of confined polyaromatic carbon species with the initial products of methane activation.
116 citations
TL;DR: Gas evolution pattern depends on both pyrolysis temperature and the feed composition, and propylene was found more dominating among other major components of gases like methane, ethane, ethylene, propane, n-butane, 1-butene, isobutylene and n-pentane etc.
99 citations
TL;DR: The dynamics of carbon monoxide on Cu surfaces was investigated during CO reduction, providing insight into the mechanism leading to the formation of hydrogen, methane, and ethylene, the three key products in the electrochemical reduction of CO2.
Abstract: The dynamics of carbon monoxide on Cu surfaces was investigated during CO reduction, providing insight into the mechanism leading to the formation of hydrogen, methane, and ethylene, the three key products in the electrochemical reduction of CO2 . Reaction order experiments were conducted at low temperature in an ethanol medium affording high solubility and surface-affinity for carbon monoxide. Surprisingly, the methane production rate is suppressed by increasing the pressure of CO, whereas ethylene production remains largely unaffected. The data show that CH4 and H2 production are linked through a common H intermediate and that methane is formed through reactions among adsorbed H and CO, which are in direct competition with each other for surface sites. The data exclude the participation of solution species in rate-limiting steps, highlighting the importance of increasing surface recombination rates for efficient fuel synthesis.
95 citations
TL;DR: In this article, a novel catalytic hydrotreating process for the heavy fraction of bio-oil, including depolymerization, decarboxylation, decarbonylation, hydrogenation and hydrodeoxygenation (HDO), is proposed with Ru/α-Al 2 O 3 catalyst and super/subcritical ethanol.
79 citations
TL;DR: In this article, the physicochemical properties of the prepared catalysts were investigated by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) model, Transmission electron microscopy (TEM) and temperature-programmed desorption of ammonia (NH3-TPD) analysis.
66 citations
65 citations
TL;DR: A tandem catalytic bed of CeO2 and HZSM-5 in an analytical pyrolyzer to enhance the hydrocarbon production from co-pyrolysis of corn stover and LDPE is developed, providing an efficient method to produce high-quality biofuels from renewable biomass resources.
62 citations
TL;DR: It is demonstrated thatgraphitic carbon will slowly deposit on the cobalt catalysts during CO hydrogenation, thereby influencing CO conversion and the FT product distribution in a way similar to that for predeposited graphitic carbon.
Abstract: One of the well-known observations in the Fischer–Tropsch (FT) reaction is that the CH4 selectivity for cobalt catalysts is always higher than the value expected on the basis of the Anderson–Schulz–Flory (ASF) distribution. Depositing graphitic carbon on a cobalt catalyst strongly suppresses this non-ASF CH4, while the formation of higher hydrocarbons is much less affected. Carbon was laid down on the cobalt catalyst via the Boudouard reaction. We provide evidence that the amorphous carbon does not influence the FT reaction, as it can be easily hydrogenated under reaction conditions. Graphitic carbon is rapidly formed and cannot be removed. This unreactive form of carbon is located on terrace sites and mainly decreases the CO conversion by limiting CH4 formation. Despite nearly unchanged higher hydrocarbon yield, the presence of graphitic carbon enhances the chain-growth probability and strongly suppresses olefin hydrogenation. We demonstrate that graphitic carbon will slowly deposit on the cobalt catalys...
TL;DR: It is found that coke formed during the MDA reaction inside the zeolite pores is essentially a zeolites-templated carbon material, which is important for the development of these interesting materials.
Abstract: Surface carbon (coke, carbonaceous deposits) is an integral aspect of methane dehydroaromatization catalyzed by Mo/zeolites. We investigated the evolution of surface carbon species from the beginning of the induction period until the complete catalyst deactivation by the pulse reaction technique, TGA, 13C NMR, TEM, and XPS. Isotope labeling was performed to confirm the catalytic role of confined carbon species during MDA. It was found that "hard" and "soft" coke distinction is mainly related to the location of coke species inside the pores and on the external surface, respectively. In addition, MoO3 species act as an active oxidation catalyst, reducing the combustion temperature of a certain fraction of coke. Furthermore, after dissolving the zeolite framework by HF, we found that coke formed during the MDA reaction inside the zeolite pores is essentially a zeolite-templated carbon material. The possibility of preparing zeolite-templated carbons from the most available hydrocarbon feedstock is important for the development of these interesting materials.
TL;DR: In this paper, the effect of CuO loading on NH4-ZSM-5 support for conversion of methanol to gasoline range hydrocarbons was investigated by using sono-chemistry methods.
Abstract: In this article, the catalytic conversion of methanol to gasoline range hydrocarbons has been studied over CuO/ NH4-ZSM-5(3,5,7,9%) catalysts prepared via sono-chemistry methods. In order to improve, copper oxide can be used as a booster on NH4-ZSM-5 this catalyst property. Accordingly, the conversion process of Methanol to Gasoline (MTG) was conducted under a pressure of 1 atm and temperature of 400°C by a fixed-bed reactor on copper oxide catalysts which were prepared based on synthetic NH4-ZSM-5. The synthetic catalyst was investigated by such analyses as BET, XRD, FT-IR, and SEM. Formation of copper oxide phase and proper distribution of copper oxide were proven on the basic level of using XRD analysis. BET analysis showed the reduction in catalyst level and SEM images depicted the proper distribution of particles. The present investigation is to study the effect of CuO loading on NH4-ZSM-5 support for conversion of methanol to gasoline range hydrocarbons. A series of CuO/ NH4-ZSM-5 catalysts were prepared, characterized, and experimented for their performance on methanol conversion and hydrocarbon yield.
TL;DR: It was found that for the fuels featuring a C[double bond, length as m-dash]C double bond, the chemistry of their allylic fuel radicals and their decomposition products strongly influences the combination reactions to the initially formed aromatic ring species and as a consequence, the PAH formation tendency.
Abstract: In this study, we experimentally investigate the high-temperature oxidation kinetics of n-pentane, 1-pentene and 2-methyl-2-butene (2M2B) in a combustion environment using flame-sampling molecular beam mass spectrometry The selected C5 fuels are prototypes for linear and branched, saturated and unsaturated fuel components, featuring different C–C and C–H bond structures It is shown that the formation tendency of species, such as polycyclic aromatic hydrocarbons (PAHs), yielded through mass growth reactions increases drastically in the sequence n-pentane < 1-pentene < 2M2B This comparative study enables valuable insights into fuel-dependent reaction sequences of the gas-phase combustion mechanism that provide explanations for the observed difference in the PAH formation tendency First, we investigate the fuel-structure-dependent formation of small hydrocarbon species that are yielded as intermediate species during the fuel decomposition, because these species are at the origin of the subsequent mass growth reaction pathways Second, we review typical PAH formation reactions inspecting repetitive growth sequences in dependence of the molecular fuel structure Third, we discuss how differences in the intermediate species pool influence the formation reactions of key aromatic ring species that are important for the PAH growth process underlying soot formation As a main result it was found that for the fuels featuring a CC double bond, the chemistry of their allylic fuel radicals and their decomposition products strongly influences the combination reactions to the initially formed aromatic ring species and as a consequence, the PAH formation tendency
TL;DR: In this paper, tungsten addition to the Pt/TiO2 showed remarkably enhanced performance, a degree of deoxygenation of 86%, which was more than two times higher than that of the Pt /TiO 2.
TL;DR: In this article, high-resolution nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy experiments were applied to obtain detailed information on the hydrocarbon chemistry of three light and three heavy crude oils.
TL;DR: The transport coefficients of hydrocarbons can be expressed simply as a function of the porosity (volume fraction of void) of the microstructure, thus paving the way for shale gas recovery predictions.
Abstract: In a context of growing attention for shale gas, the precise impact of organic matter (kerogen) on hydrocarbon recovery from unconventional reservoirs still has to be assessed. Kerogen’s microstructure is characterized by a very disordered pore network that greatly affects hydrocarbon transport. The specific structure and texture of this organic matter at the nanoscale is highly dependent on its origin. In this study, by the use of statistical physics and molecular dynamics, we shed some new lights on hydrocarbon transport through realistic molecular models of kerogen at different level of maturity [Bousige et al. Nat. Mater. 2016, 15, 576]. Despite the apparent complexity, severe confinement effects controlled by the porosity of the various kerogens allow linear alkanes (from methane to dodecane) transport to be studied only via the self-diffusion coefficients of the species. The decrease of the transport coefficients with the amount of adsorbed fluid can be described by a free volume theory. Ultimately,...
TL;DR: In this paper, high-density poly(ethylene) (HD-PE) plastic deformation into liquid hydrocarbon fuel using a pyrolysis-catalytic cracking process with a copper carbonate (CuCO3) catalyst, at a temperature range from 23 °C to 390 °C.
Abstract: Waste high-density poly(ethylene) (HD-PE) plastic deformation into liquid hydrocarbon fuel using a pyrolysis-catalytic cracking process with a copper carbonate (CuCO3) catalyst, at a temperature range from 23 °C to 390 °C. The pyrolysis-catalytic deformation process will help in environmental purification. The liquid hydrocarbons collected for use as a fuel were analyzed using Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), two-dimensional gas chromatography/time of flight mass spectrometry (2D-GCxGC/TOFMS), inductively coupled plasma (ICP) analysis, and carbon, hydrogen, nitrogen, sulfur, and oxygen (CHNS/O) elemental analysis. The 2D-GCxGC/TOFMS results showed that various types of hydrocarbon compounds (aliphatics, aromatics, cyclics olefins, and phenanthrene) were available in the liquid hydrocarbon fuel. The conversion rates in four experiments which converted waste HD-PE plastic into liquid hydrocarbons for use as fuel were 85%, 90%, 94%, 92%, light gases 14.67%, 9.66%, 5.64%, 7.45% and residues 0.33%, 034%, 0.36%, 0.55%. Liquid hydrocarbons as fuel were found to be appropriate for use in petrol and diesel engines and they were found to be a good source of organic compounds/petrochemicals.
TL;DR: In this article, the effect of adding ethanol and 2,5-dimethylfuran (DMF) to gasoline has been explored to reveal the changes in physicochemical properties of soot collected at a flame height of 25mm.
TL;DR: In this article, the effect of the Pt:Pd ratio on a diesel oxidation catalysts ability to oxidize CO and different hydrocarbon types was investigated, where the concentrations and types of pollutant species were used to simulate those found in low temperature combustion (LTC) engine exhaust.
Abstract: For several reasons, typical diesel oxidation catalysts (DOCs) contain a mixture of Pt and Pd and in this study, the effect of the Pt:Pd ratio on a DOC’s ability to oxidize CO and different hydrocarbon types was investigated. The concentrations and types of pollutant species were used to simulate those found in low temperature combustion (LTC) engine exhaust. Representative hydrocarbon species were selected; C2H4 (short-chain alkene), C2H6 (short-chain alkane), C6H14 (long-chain alkane) and C7H8 (aromatic). Two types of experiments were performed, one in which the oxidation of each hydrocarbon or CO reactant was examined individually (simple feed conditions), and the second in which all reactants were added together (full feed conditions). Under the simple feed conditions, CO and C2H6 oxidation increased with increasing Pd content, while C2H4 and C6H14 oxidation improved with higher Pt content. When the full mixture of CO and hydrocarbons was used, hydrocarbon oxidation light off consistently followed that of CO, regardless of the Pt:Pd ratio, due to strong inhibition by CO. The best CO oxidation activity was observed over the Pd-only catalyst, and performance over the bimetallic samples was a function of both CO inhibition and Pt:Pd ratio. More specifically, as Pd content increased, CO inhibition was dampened, and as Pt content increased its inherent activity toward alkene oxidation became significant. Since inhibition is a function of the Pt/Pd content and the individual metals have different inherent activities toward the oxidation of different hydrocarbons, results obtained from the experiments with the simple feed could not be directly correlated to those from the experiments with the mixture of hydrocarbons.
TL;DR: In this article, a fluorine functionalized microporous indium (In) metal-organic framework (UPC-104) was proposed for light hydrocarbon storage and separation, which can be stable up to 300 °C and can retain its framework in acidic and alkaline aqueous solutions.
Abstract: The storage and separation of hydrocarbons is of great importance for the petrochemical industry. Herein, we report a fluorine-functionalized microporous indium (In) metal–organic framework (UPC-104) for light hydrocarbon storage and separation. UPC-104 can be stable up to 300 °C, and can retain its framework in acidic and alkaline aqueous solutions (pH 1–11). Remarkably, the material exhibits very high H2 (230.8 cm3 g−1, 2.06 wt% at 77 K and 1 bar), C2H2 (187.0 cm3 g−1 at 273 K and 1 bar), and C3H6/C3H8 adsorption capacity (276.5 cm3 g−1 and 250.4 cm3 g−1 for C3H6 and C3H8 at 273 K and 1 bar), and shows potential for the separation of light hydrocarbons (C2H2, C2H4, C2H6, C3H6, C3H8, n-C4H10, and i-C4H10 relative to CH4), as shown by single component gas sorption and selectivity calculations.
TL;DR: In this article, the evaporation rates of 14 intermediate-volatility organic compounds (IVOCs) were investigated with half of them losing more than 95% of their mass in less than one month.
TL;DR: In this paper, an extensive review has been made on the effectiveness of metallic catalyst in hydrocarbon reforming for COX free hydrogen production via different techniques and the effect of reaction temperature, gas hour space velocity and metal loading on the sustainability of thermocatalytic decomposition TCD of methane.
TL;DR: In this paper, two types of vacuum-imbibition tests were performed on 20 shale oil rock samples to distinguish these two porosities and two saturations, and the results indicated that, for the shale rock samples tested, the maximum possible oil content in organic matter ranges from 6% to 55% of the total oil content, and 50% to 90% of organic oil content is ad-and absorbed in kerogen.
TL;DR: In this article, lower onset potentials for hydrocarbon products were observed during the electrochemical reduction of carbon dioxide (CO2RR) on copper particles (40-60nm) coated with a thin layer of ruthenium via galvanic displacement, referred to as Ru@Cu.
Abstract: Lower onset potentials for hydrocarbon products were observed during the electrochemical reduction of carbon dioxide (CO2RR) on copper particles (40–60 nm) coated with a thin layer of ruthenium via galvanic displacement, referred to as Ru@Cu. Hydrocarbons detected include ethane, ethylene, acetate, ethanol, propanol and CO. In the case of ethane (C2H6), the onset potential is 200 mV lower on Ru@Cu than on bare Cu particles. Increasing Ru coverage decreases the CO2RR activity while hydrogen evolution (HER) activity increased substantially. An optimum Ru coverage was found when the displacement was performed for 10 s. The results presented here highlight the importance of surface chemistry in determining reaction selectivity.
TL;DR: In this article, a single cylinder port fuel injected spark ignition engine prototype was evaluated using a variety of test fuels such as compressed natural gas, 10, 20, 30, 50, 70% and hydrogen for in-depth understanding of relative particulates and gaseous emissions, in addition to determining the engine's knocking characteristics.
TL;DR: Dual catalyst layout shows a new opportunity for efficient conversion of biomass materials into hydrocarbons, and the selectivities towards benzene increased, at higher co-feeding ratios, while that of toluene shows an opposite trend.
TL;DR: In this article, a biochar catalyst derived from corn stover biochar was prepared for the experiment and the results showed that the highest amounts of hydrocarbons (52.77% of bio-oil) were achieved from microwave-assisted catalytic pyrolysis of Douglas fir pellets was performed in a microwave reactor.
Abstract: In the present study, in situ catalytic pyrolysis of Douglas fir pellets was performed in a microwave reactor. A biochar catalyst derived from corn stover biochar was prepared for the experiment. The results showed that the highest amounts of hydrocarbons (52.77% of bio-oil) were achieved from microwave-assisted catalytic pyrolysis over the biochar catalyst at a reaction temperature of 480 °C. A non-condensable gas enriched in H2, CO, and CO2 was observed and analyzed by micro-GC. The amounts of H2 and CO increased during catalytic pyrolysis compared to the non-catalytic runs. GC/MS analysis results showed that the quantity of lignin-derived guaiacols decreased dramatically with the increase of the ratio of catalyst to biomass. The biochar catalyst exhibited good selectivity towards hydrocarbon and phenol compounds, simplifying the chemical composition, reducing undesirable compounds and producing pyrolysis oil in an acceptable yield. The reaction mechanism for hydrocarbon production from catalytic pyrolysis was also analyzed.
TL;DR: In this paper, the effect of operating parameters for upcycling waste plastics into CNTs and hydrogen in a fluidized-bed system was investigated, and the reaction temperature and equivalence ratio (ER) were evaluated for CNT and hydrogen coproduction.
Abstract: The waste plastic gasification in a fluidized bed for a continuous carbon nanotube (CNT) and hydrogen coproduction is a potential method for sustainable management. Ni/Al2O3 catalysts have been synthesized by the impregnation method to upgrade hydrogen production and CNT synthesis. However, few studies investigated the effect of operating parameters for upcycling waste plastics into CNTs and hydrogen in the fluidized-bed system. The reaction temperature and the equivalence ratio (ER) were evaluated for CNT and hydrogen coproduction. Increasing the reaction temperature and lowering the ER enhanced the methane dry reforming, hydrocarbon dry reforming, and hydrocarbon direct decomposition for hydrogen and CNT coproduction. While increasing the reaction temperature from 500 to 700 °C can obtain higher CNT yield and H2 production rate, the system heated to 700 °C and maintained at this temperature should provide more energy. Moreover, the gas composition at 600 °C with 0.1 ER contained more CH4 and C2–C5 hydro...
TL;DR: For being the first study to report chemical oxidation of oil hydrocarbons in real contaminated sediments, it may have practical implications to design a remediation strategy for target contaminants.