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The cost-effective separation of ethylene (C2H4), ethyne (C2H2), and ethane (C2H6) poses a significant challenge in the contemporary chemical industry. In contrast to the energy-intensive high-pressure cryogenic distillation process, zeolite-based adsorptive separation offers a low-energy alternative. This review provides a concise overview of recent advancements in the adsorptive separation of C2H4, C2H2, and C2H6 using zeolites or zeolite-based adsorbents. It commences with an examination of the industrial significance of these compounds and the associated separation challenges. Subsequently, it systematically examines the utilization of various types of zeolites with diverse cationic species in such separation processes. And then it explores how different zeolitic structures impact adsorption and separation capabilities, considering principles such as cation-π interaction, π-complexation, and steric separation concerning C2H4, C2H2, and C2H6 molecules. Furthermore, it discusses methods to enhance the separation performance of zeolites and zeolite-based adsorbents, encompassing structural design, modifications, and ion exchange processes. Finally, it summarizes current research trends and future directions, highlighting the potential application value of zeolitic materials in the field of C2H4, C2H2, and C2H6 separation and offering recommendations for further investigation. [ABSTRACT FROM AUTHOR]

In studying the effects of oxygen concentration and molecular structure on the morphologies of the soot particles produced by hydrocarbon fuels, ethylene and ethane were chosen as experimental fuels. With a Gülde laminar coaxial diffusion flame device, a soot particle device was used to sample soot particles at different oxygen concentrations (21%, 24%, 26%, 28%, and 31%) and at different heights above a burner (HABs = 10 mm, 20 mm, 30 mm, 40 mm, and 50 mm). High-resolution transmission electron microscopy (HRTEM) was used to scrutinize and analyze the soot particles at varying oxygen concentrations. The findings suggest that at the same oxygen concentration, ethylene produces brighter and taller flames. With an increase in the oxygen concentration, ethylene flames and ethane flames gradually decrease in height and become brighter. With an increase in the HAB, the average primary soot particle diameter (Dp) increases initially and then decreases, the fractal dimension (Df) increases, and the aggregates transition from strips and chains to clusters. At the same flame height (HAB = 30 mm), the Dp decreases, the Df increases, the carbon layer torsion resistance (Tf) and the carbon layer spacing (Ds) increase, and the carbon layer changes from a parallel arrangement to a curved arrangement to form denser network aggregations. [ABSTRACT FROM AUTHOR]

This study explores the tuning of a Pd/Al2O3 hydrogenation catalyst for the selective removal of trace acetylene from ethylene-rich feeds by coating the catalyst with non-functionalized and functionalized ionic liquids (denoted as SCILL and Advanced SCILL materials, respectively). These materials were tested in an automated continuous hydrogenation rig converting 3300 ppm of acetylene in excess ethylene, a gas mixture mimicking a technical front-end steam cracker feed composition. While the sulfonic-acid-functionalized IL coating resulted in a highly active but very unselective catalyst converting mainly ethylene to ethane, an Advanced SCILL catalyst prepared from a nitrile-functionalized IL reduced the acetylene concentration down to less than 1 ppm, while leaving over 99% of the ethylene untouched. We also examined the potential transformations of the IL layer under reaction conditions by means of 1H NMR. Except for a ketone-functionalized IL, which was inherently labile, all tested ILs primarily underwent C2-ethylation or remained unaltered. Our findings highlight the great potential of functionalized ILs in modifying heterogeneous hydrogenation catalysts.

In studying the effects of oxygen concentration and molecular structure on the morphologies of the soot particles produced by hydrocarbon fuels, ethylene and ethane were chosen as experimental fuels. With a Gülde laminar coaxial diffusion flame device, a soot particle device was used to sample soot particles at different oxygen concentrations (21%, 24%, 26%, 28%, and 31%) and at different heights above a burner (HABs = 10 mm, 20 mm, 30 mm, 40 mm, and 50 mm). High-resolution transmission electron microscopy (HRTEM) was used to scrutinize and analyze the soot particles at varying oxygen concentrations. The findings suggest that at the same oxygen concentration, ethylene produces brighter and taller flames. With an increase in the oxygen concentration, ethylene flames and ethane flames gradually decrease in height and become brighter. With an increase in the HAB, the average primary soot particle diameter (Dp) increases initially and then decreases, the fractal dimension (Df) increases, and the aggregates transition from strips and chains to clusters. At the same flame height (HAB = 30 mm), the Dp decreases, the Df increases, the carbon layer torsion resistance (Tf) and the carbon layer spacing (Ds) increase, and the carbon layer changes from a parallel arrangement to a curved arrangement to form denser network aggregations.

Ethylene production has a negative environmental impact, with its separation step being one of the major contributors of pollution. This has encouraged the search for energy-efficient alternatives, among which the adsorptive separation of ethane and ethylene stands out. ZIF-8 is a molecular sieve that is potentially useful for this purpose. It is selective to ethane, an exceptional property that remains unexplained. Furthermore, the adsorption of ethane and ethylene above room temperature, such as at steam cracking process outlet temperatures, has not been addressed either. This work aims to fill this knowledge gap by combining experiments at very low volumetric fillings with density–functional theory modelling methods. Adsorption isotherms of ethane and ethylene on ZIF-8 at pressures below 0.3 bar and 311 K, 333 K, and 363 K were measured using zero-length column chromatography. The low-pressure domain of the isotherms contains information on the interactions between the adsorbate molecules and the adsorbent. This favors the understanding of their macroscopic behavior from simulations at the atomic level. The isosteric enthalpy of adsorption of ethane remained constant at approximately −10 kJ/mol. In contrast, the isosteric enthalpy of adsorption of ethylene decreased from −4 kJ/mol to values akin to those of ethane as temperature increased. ZIF-8 selectivity to ethane, estimated from ideal adsorbed solution theory, decreased from 2.8 to 2.0 with increasing pressure up to 0.19 bar. Quantum mechanical modelling suggested that ethylene had minimal interactions with ZIF-8, while ethane formed hydrogen bonds with nitrogen atoms within its structure. The findings of this research are a platform for designing new systems for the adsorptive separation of ethane and ethylene and thus, reducing the environmental impact of ethylene production. [ABSTRACT FROM AUTHOR]

Objective This paper discusses the quality requirements of ethane for the production of ethylene to determine the different quality requirements of ethane for different utilization and transportation ways, and further discusses the detection methods of different quality indicators of ethane in order to provide technical support for the relevant industry producing ethane from natural gas.Methods This paper mainly refers to the quality requirements of ethane products in the American Gas Processing Engineering Data Manual (GPSA) and the PetroChina enterprise standard of Q/SY 01027-2019 Technical specification of ethane extracted from natural gas. Based on these two documents, the quality requirements and indexes of gaseous and liquid ethane products in China were studied and discussed intensively, respectively. Results The ethane products may be divided into three classes according to their gaseous and liquid characteristics. Ethane products come from natural gas, so it is appropriate to use natural gas sampling method for sampling and to use related analysis and test standards of natural gas for its main quality determination. Conclusions At present, there are no national or industrial standards for ethane products in China. It is suggested that the relevant departments should faciliate the development process of national or industrial standards for ethane products to uniformly regulate the quality indicators, classification, inspection rules and delivery acceptance of ethane products. And then it can provide technical support for the implementation of ethane recovery projects, as well as promote the establishment of China’s ethane market and production system. [ABSTRACT FROM AUTHOR]

The existing fundamental similarities in the chemistry of structurally related carbon and silicon compounds have been demonstrated. Stable silicon analogs of ethylene, silenes or silaethylenes R2C=SiR2 and disilenes R2Si=SiR2, as well as ethyne (acetylene) analogs, disilynes RSi≡SiR, have been considered. A number of unique branched (bulky) organic and organosilicon substituents have been described; the introduction of such substituents to double- or triple-bonded silicon atoms makes it possible to protect the latter from the action of atmospheric oxygen and moisture and prevent secondary dimerization (oligomerization) processes. Examples are given of steric protection for obtaining kinetically stable unsaturated silicon compounds which were characterized by IR, NMR, and UV-Vis spectroscopy and X-ray analysis. [ABSTRACT FROM AUTHOR]

Co/TiO2 catalysts with different cobalt loadings (3.8, 7.5 and 15 wt%) were prepared by impregnation method of Co(NO3)2 6H2O over titania. Samples containing Co(NO3)2·6H2O and TiO2 in stoichiometric proportions in order to obtain CoTiO3 and Co2 TiO4 phases were also synthesized. The effect of the calcination treatment at two different temperatures, 550 and 1150 °C, was investigated. Characterizations by several techniques, such as XRD, UV–vis–NIR, DRS, Raman and XPS, were carried out. XRD showed the coexistence of three phases: CoTiO3; Co2TiO4 and Co3O4 after calcination at 550 °C, while calcination at high temperature (1150 °C) led to single-phase systems (CoTiO3 or Co2TiO4). Diffuse reflection and XPS spectroscopy showed that divalent cobalt occupies octahedral sites in the ilmenite phase, and both tetrahedral and octahedral sites in the spinel phase. The catalytic performances of the prepared catalysts were evaluated in the oxidative dehydrogenation reaction (ODH) of ethane to ethylene, as a function of the Co content for Co/TiO2 catalysts and as a function of the calcination temperatures for the CoTiO3 and Co2TiO4 phases. Co(7.5)/TiO2 was the most active, although the conversion of ethane decreased in the first 150 min of the reaction, reaching values comparable to those of Co2TiO4 and CoTiO3; however, Co(7.5)/TiO2 was confirmed as having the best selectivity to ethylene in comparison with the bulk phases, CoTiO3 and Co2TiO4. The influence of the reaction mixture composition, specifically the presence of water, at different percentages, was investigated. There is a decrease in the overall ethane conversion and an increase in the ethylene selectivity when the percentage of water increases. This behavior can likely be attributed to an increase in the surface concentration of hydroxyl species (OH), resulting in heightened surface acidity. [ABSTRACT FROM AUTHOR]

We report herein the preparation, characterization, and catalytic performance of a series of heterogeneous catalysts featuring highly dispersed zinc sites on zeolitic SSZ-13 and ZSM-5 frameworks. The materials are evaluated in the CO2-assisted oxidative ethane dehydrogenation, a very important reaction for the synthesis of platform chemicals. In particular, we find that Zn2.92/SSZ-13 exhibits high reactivity in the conversion of C2H6 and CO2 and high ethene selectivity. In line with the experimental results, we show that the selective character of the catalyst is due to the characteristic compositional structure of the support and its topology that can effectively confine CO2 molecules. An in-depth molecular analysis via operando studies and DFT calculations shows that the rate-limiting step of the reaction with CO2 is the second C-H bond dissociation to give C2H4. The addition of CO2 effectively reduces the energy barrier of this step, favoring desorption of C2H4 while limiting byproduct formation. Overall, this work demonstrates the breakthrough potential of catalysts made of highly dispersed zinc species on zeolites in relevant transformations.

The single atom catalysts (SACs) show unique catalytic performance in heterogeneous reactions owing to unsaturated coordination sites and high metal atom dispersion. Herein, a simple wet impregnation method was utilized to synthetize of Fe−Al2O3 catalysts. The Fourier transformation infrared spectroscopy (FTIR) revealed that abundant OH group attached to the support (Al2O3) surface facilitating formation of isolated Fe single atom. High resolution transmission electron microscope (HR‐TEM) and extended X‐ray absorption fine structure (EXAFS) confirmed the Fe single atom architecture. Fe−Al2O3 (4.5 wt %) performed enhanced stability and activity on ethane dehydrogenation reaction. [ABSTRACT FROM AUTHOR]

Glycerin, a low-valued waste from biodiesel production, and dopamine were used as precursors for adsorbent materials. The study is centered on the preparation and application of microporous activated carbon as adsorbent materials in the separation of ethane/ethylene and of gases that are natural gas or landfill gas components (ethane/methane and carbon dioxide/methane). The activated carbons were produced by the following sequence reactions: facile carbonization of a glycerin/dopamine mixture and chemical activation. Dopamine allowed the introduction of nitrogenated groups that improved the selectivity of the separations. The activating agent was KOH, but its mass ratio was kept lower than one to improve the sustainability of the final materials. The solids were characterized by N2 adsorption/desorption isotherms, SEM, FTIR spectroscopy, elemental analysis, and point of zero charges (pHPZC). The order for adsorption of the different adsorbates (in mmolg−1) on the most well performing material—Gdop0.75—is methane (2.5) < carbon dioxide (5.0) < ethylene (8.6) < ethane (8.9). [ABSTRACT FROM AUTHOR]

Ethylene (C2H4) is a major chemical for the modern society, and new technologies for its production are of strategic importance globally. Recently, oxidative dehydrogenation of ethane (C2H6) using CO2 as a milder oxidant (CO2‐ODH) is proposed as a potential way for C2H4 production, and development of effective catalysts for the process is drawing wide attention. Here, we report on a facilely prepared ZSM‐5 supported Zn system, i. e., ZnZSM‐5, which showed great promise in CO2‐ODH. Samples with different Zn loadings were prepared and evaluated, and the highest performance was obtained over 0.05ZnZSM‐5 at 700 °C and a CO2:C2H6 feeding ratio of 5 : 1. During 340 min TOS, the C2H6 conversion decreased moderately from 36.2 % to 23.1 %, and the C2H4 yield stabilized at 21.9 % to 27.9 %. Based on systematic characterization and investigation of reaction conditions, the structure‐performance relationship and reaction network were discussed in detail. [ABSTRACT FROM AUTHOR]

Ethylene (C2H4) is a major chemical for the modern society, and new technologies for its production are of strategic importance globally. Recently, oxidative dehydrogenation of ethane (C2H6) using CO2 as a milder oxidant (CO2‐ODH) is proposed as a potential way for C2H4 production, and development of effective catalysts for the process is drawing wide attention. Here, we report on a facilely prepared ZSM‐5 supported Zn system, i. e., ZnZSM‐5, which showed great promise in CO2‐ODH. Samples with different Zn loadings were prepared and evaluated, and the highest performance was obtained over 0.05ZnZSM‐5 at 700 °C and a CO2:C2H6 feeding ratio of 5 : 1. During 340 min TOS, the C2H6 conversion decreased moderately from 36.2 % to 23.1 %, and the C2H4 yield stabilized at 21.9 % to 27.9 %. Based on systematic characterization and investigation of reaction conditions, the structure‐performance relationship and reaction network were discussed in detail. [ABSTRACT FROM AUTHOR]

Adsorptive separation is an energy‐efficient alternative, but its advancement has been hindered by the challenge of industrially potential adsorbents development. Herein, a novel ultra‐microporous metal‐organic framework ZU‐901 is designed that satisfies the basic criteria raised by ethylene/ethane (C2H4/C2H6) pressure swing adsorption (PSA). ZU‐901 exhibits an "S" shaped C2H4 curve with high sorbent selection parameter (65) and could be mildly regenerated. Through green aqueous‐phase synthesis, ZU‐901 is easily scalable with 99 % yield, and it is stable in water, acid, basic solutions and cycling breakthrough experiments. Polymer‐grade C2H4 (99.51 %) could be obtained via a simulating two‐bed PSA process, and the corresponding energy consumption is only 1/10 of that of simulating cryogenic distillation. Our work has demonstrated the great potential of pore engineering in designing porous materials with desired adsorption and desorption behavior to implement an efficient PSA process. [ABSTRACT FROM AUTHOR]

NiO-based catalysts are among the most active and selective catalytic systems for low-temperature oxidative dehydrogenation (ODH) of ethane into ethylene and, therefore, they have been extensively studied in the last twenty-five years. This paper reviews the most relevant works focusing on NiO-based catalysts for ethane ODH, including promoted and unpromoted, bulk and supported NiO. The effects of the nature of the promoter and of the support together with the influence of the method of preparation used on their activity in ethane ODH are discussed in detail as they were shown to be key factors controlling the catalytic performance, including the catalyst stability. The reaction mechanism involved in ethane ODH reaction over NiO-based catalysts is also presented and discussed.

Two C2H6‐selective metal‐organic framework (MOF) adsorbents with ultrahigh stability, high surface areas, and suitable pore size have been designed and synthesized for one‐step separation of ethane/ethylene (C2H6/C2H4) under humid conditions to produce polymer‐grade pure C2H4. Experimental results reveal that these two MOFs not only adsorb a high amount of C2H6 but also display good C2H6/C2H4 selectivity verified by fixed bed column breakthrough experiments. Most importantly, the good water stability and hydrophobic pore environments make these two MOFs capable of efficiently separating C2H6/C2H4 under humid conditions, exhibiting the benchmark performance among all reported adsorbents for separation of C2H6/C2H4 under humid conditions. Moreover, the affinity sites and their static adsorption energies were successfully revealed by single crystal data and computation studies. Adsorbents described in this work can be used to address major chemical industrial challenges. [ABSTRACT FROM AUTHOR]

Comparative results of studying the oxidative dehydrogenation of ethane (ODE) on catalytic vanadium-phosphorus oxide systems deposited by the molecular layering method on the surface of oxide supports (Al2O3, SiO2) have been presented. It has been found that the highest activity in ODE and selectivity for ethylene are exhibited by vanadium-phosphorus-containing catalysts. The influence of the acidity of catalytic systems on the activity and selectivity of the process has been revealed. The selectivity of the ODE process for ethylene reaches 90%. An increase in the oxygen concentration in the initial mixture from 3.5 to 20% leads mainly to a decrease in the selectivity of the ODE process with respect to the ethylene yield. [ABSTRACT FROM AUTHOR]

In search of a more effective process of ethane oxidative hydrogenation, different operation modes (thermal and microwave heating) are compared. The catalyst Mo1-V0.3-Te0.13-Nb0.11-Ox was prepared by hydrothermal synthesis and characterized by a set of physicochemical methods (XRD, N2 adsorption, SEM, EDX). The direct microwave heating of the catalyst layer is proposed as an alternative way of energy-saving ethane-to-ethylene oxidation by a Mo-V-Te-Nb-Ox system. A substantial decrease in the reactor temperature upon the microwave-assisted process is accompanied by extremely high catalyst selectivity, which remains at a very high level of 98+%. [ABSTRACT FROM AUTHOR]

The process of oxidative dehydrogenation of ethane (ODE) at an elevated pressure over a MoVNbTeOx mixed oxide catalyst is studied. It is found that when the reaction is carried out at 280°C, the fraction of the total amount of reacted oxygen consumed for the formation of ethylene decreases from 100 to 68% with the increase in pressure from 0.1 to 10.0 MPa, which may indicate an increase in the role of chemisorbed oxygen in the ODE process at a high pressure. Here, the productivity with respect to ethylene at 280°C and 10.0 MPa is higher in comparison with the value obtained at 360°C and 0.1 MPa. [ABSTRACT FROM AUTHOR]

Developing C 2 H 6 -selective adsorbents for efficient separation of C 2 H 6 /C 2 H 4 is of great significance for the petrochemical industry. Numerous C 2 H 6 -selective adsorbents have been created, but their applicability in real-world industrial settings is severely constrained by their unscalable production and generally low stability (particularly water resistance). Herein, we proposed a series of C 2 H 6 -selective adsorbents CUPMOF-2-M (M = Zn, Mn, Cu, Mg), in which CUPMOF-2-Zn (also termed MET-6) not only possesses good C 2 H 6 -selective separation effect but super-hydrophobicity and low cost. At 298 K and 80 % relative humidity, CUPMOF-2-Zn only adsorbs 0.4 mmol·g−1 of water, outperforming all previously reported C 2 H 6 -selective materials in terms of hydrophobicity. Moreover, dynamic breakthrough experiments solidly demonstrated that CUPMOF-2-Zn can efficiently separate C 2 H 6 /C 2 H 4 in high humidity conditions. More importantly, CUPMOF-2-Zn can be synthesized in a large-scale at room temperature (one batch 10 kg), which is essential to industrial implementation for separation of C 2 H 6 /C 2 H 4. [Display omitted] [ABSTRACT FROM AUTHOR]

Ethylene production has a negative environmental impact, with its separation step being one of the major contributors of pollution. This has encouraged the search for energy-efficient alternatives, among which the adsorptive separation of ethane and ethylene stands out. ZIF-8 is a molecular sieve that is potentially useful for this purpose. It is selective to ethane, an exceptional property that remains unexplained. Furthermore, the adsorption of ethane and ethylene above room temperature, such as at steam cracking process outlet temperatures, has not been addressed either. This work aims to fill this knowledge gap by combining experiments at very low volumetric fillings with density–functional theory modelling methods. Adsorption isotherms of ethane and ethylene on ZIF-8 at pressures below 0.3 bar and 311 K, 333 K, and 363 K were measured using zero-length column chromatography. The low-pressure domain of the isotherms contains information on the interactions between the adsorbate molecules and the adsorbent. This favors the understanding of their macroscopic behavior from simulations at the atomic level. The isosteric enthalpy of adsorption of ethane remained constant at approximately −10 kJ/mol. In contrast, the isosteric enthalpy of adsorption of ethylene decreased from −4 kJ/mol to values akin to those of ethane as temperature increased. ZIF-8 selectivity to ethane, estimated from ideal adsorbed solution theory, decreased from 2.8 to 2.0 with increasing pressure up to 0.19 bar. Quantum mechanical modelling suggested that ethylene had minimal interactions with ZIF-8, while ethane formed hydrogen bonds with nitrogen atoms within its structure. The findings of this research are a platform for designing new systems for the adsorptive separation of ethane and ethylene and thus, reducing the environmental impact of ethylene production.

Objective The co-cracking technology of ethane and propane is optimized. Methods The BSPA ethylene cracking evaluation test equipment of KBR company is used to optimize the separate cracking of ethane and propane and the blending cracking technology according to different ratios in the laboratory. Results When the blend proportion of ethane is 20 %- 90 %, t he yields of ethylene, diene and triene are increased. When the blend proportion of ethane is 80%-90%, the highest yields of ethylene, diene and triene are 55. 28 %, 56. 05 % and 58. 01 %, respectively. Conclusion T he optimized result is applied in industrial ethylene cracking plant, the total ethylene yield and the diene yield don't decrease when the proportion of light cracking feedst0ck in t he whole cracking feedstock reduced more than 10%, and the remarkable industrial application effect has been obtained. [ABSTRACT FROM AUTHOR]

Redox conversion of ethane at 600 °C on Mo-containing oxide systems differing in the composition and preparation method was studied. The ethane conversion and the selectivity of the ethylene formation increase in the series of MoO3 samples supported on SiO2 (silica gel), TiO2 (anatase), and alumina. The efficiency of the MoO3/Al2O3 systems increased when HNO3 was added to a (NH4)6Mo7O24 solution used to impregnate the support, and also when γ-Al2O3 was replaced with Al(OH)3. Gallium oxide additives improve the properties of the MoO3/Al2O3 system, increasing the ethane conversion to 44% at ethylene formation selectivity of more than 96%. The systems under consideration are characterized by high stability and retain their activity after five reaction—regeneration cycles. Based on the data obtained during the reaction of ethane with the Mo systems and in the course of regeneration of the reduced samples with oxygen, the content of active oxygen corresponding to the MoO3 ↔ MoO2 transformation was assessed. [ABSTRACT FROM AUTHOR]

Cobalt-exchanged ZSM-5 catalyzes the ammoxidation of ethane (2 C 2 H 6 + 3 O 2 + 2 NH 3 → 2 CH 3 CN + 6 H 2 O), yet the active form of cobalt, the role of the Brønsted acidic zeolite, and the reaction pathways remain elusive. Comparisons of rates and selectivities of reactions at distinctive cobalt sites (Co2+ at Al pair sites (CoZ 2), Co 3 O 4 , cobalt phyllosilicate, and cobalt aluminate) suggest sites that form from CoZ 2 provide the greatest rates and selectivities for CH 3 CN and C 2 H 4 formation. Significantly, we revealed a large fraction of CH 3 CN appears to form directly through a trimolecular reaction at cobalt ions without desorption of intermediates. In parallel, a more conventional sequential pathway dehydrogenates C 2 H 6 , aminates C 2 H 4 , and oxidatively dehydrogenates C 2 H 5 NH 2 to produce CH 3 CN. Combined rate measurements with temperature programmed reactions and in situ infrared spectra demonstrate that O 2 -derived intermediates at cobalt ions initiate both reaction sequences by abstracting H-atom from C 2 H 6. [Display omitted] • Standard synthesis creates different distributions of cobalt species within H-ZSM-5. • ZSM-5 with cobalt ions only at Al pair sites gives greatest rates and selectivities. • O 2 -derived intermediates abstract H-atoms from C 2 H 6 to initiate the reaction. • CH 3 CN forms by a trimolecular primary reaction among C 2 H 6 , NH 3 , and O 2 at cobalt. • A parallel pathway forms CH 3 CN by C 2 H 4 amination and dehydrogenation. [ABSTRACT FROM AUTHOR]

Glycerin, a low-valued waste from biodiesel production, and dopamine were used as precursors for adsorbent materials. The study is centered on the preparation and application of microporous activated carbon as adsorbent materials in the separation of ethane/ethylene and of gases that are natural gas or landfill gas components (ethane/methane and carbon dioxide/methane). The activated carbons were produced by the following sequence reactions: facile carbonization of a glycerin/dopamine mixture and chemical activation. Dopamine allowed the introduction of nitrogenated groups that improved the selectivity of the separations. The activating agent was KOH, but its mass ratio was kept lower than one to improve the sustainability of the final materials. The solids were characterized by N2 adsorption/desorption isotherms, SEM, FTIR spectroscopy, elemental analysis, and point of zero charges (pHPZC). The order for adsorption of the different adsorbates (in mmolg−1) on the most well performing material—Gdop0.75—is methane (2.5) < carbon dioxide (5.0) < ethylene (8.6) < ethane (8.9).

Photocatalytic oxidative dehydrogenation of ethane to ethylene with a high selectivity is an attractive reaction. In this study, different types of heterojunctions between Pd/TiO 2 and a second metal oxide semiconductor were designed and synthesized to realize high activity conversion of C 2 H 6 to C 2 H 4. Pd/TiO 2 -AgO heterojunction was proved with best reaction performance. The addition of AgO facilitated the activation of reactant molecules. It enhanced directional transfer of electron-hole pairs and separation efficiency of photogenerated carriers. Pd/TiO 2 -5 % AgO heterojunction was proved with the best separation ability of photogenerated carriers and the largest number of surface hydroxyl groups. Detailed charge transfer path and reaction mechanism were proposed and discussed. [Display omitted] • Different heterojunctions were evaluated for photocatalytic ethane-to-ethylene. • Semiconductors with lower VB and CB are beneficial for ethylene formation. • Combined DFT and in situ-FTIR to Investigate the reaction mechanism. • Quantitatively assessed the influence of capture agents on different products. [ABSTRACT FROM AUTHOR]

Based on Materials Studio and Aspen Plus, the reaction mechanism of producing benzene and styrene from ethane steam heat lysis was investigated through the addition reaction of free radicals + alkenes or free radicals + alkynes to form large free radicals and then through the cyclization and dehydrogenation of large free radicals to form aromatic hydrocarbons. It was found the thermal cracking of ethane had 2 paths to form benzene and 1 path to form styrene. The 1st path to form benzene is that the product ethylene form C2H3• through a chain transfer, then C2H3• and ethylene additively react to form 1-C4H7•-4, which then reacts with ethylene to form C6H11•, and finally, benzene is produced by dehydrogenation and transfer of C6H11•. The 2nd path to form benzene is that acetylene is produced by dehydrogenation of C2H3•, and then acetylene reacts via two sub-paths to form 1,3-C4H5•-4, which is cyclized to form C6H9•, and finally, benzene is formed through dehydrogenation and transfer. The path to form styrene is that 1,3-C4H5•-4 and 1,3-butadiene are cyclized to form C8H11•, and styrene is finally formed through dehydrogenation and chain transfer. Comparative analysis with industrial data showed there were 3 cycles in the ethane thermal cracking reaction network. The simulation data were well consistent with the industrial production data.

In search of a more effective process of ethane oxidative hydrogenation, different operation modes (thermal and microwave heating) are compared. The catalyst Mo1-V0.3-Te0.13-Nb0.11-Ox was prepared by hydrothermal synthesis and characterized by a set of physicochemical methods (XRD, N2 adsorption, SEM, EDX). The direct microwave heating of the catalyst layer is proposed as an alternative way of energy-saving ethane-to-ethylene oxidation by a Mo-V-Te-Nb-Ox system. A substantial decrease in the reactor temperature upon the microwave-assisted process is accompanied by extremely high catalyst selectivity, which remains at a very high level of 98+%.

The results of an experimental study of the partial oxidation of ethane in the temperature range 773–1023 K and at pressures of 1 and 2 atm in a flow reactor with chromatographic analysis of the gas mixture were presented. Oxygen and nitrogen were used as an oxidizer and carrier gas, respectively. The excess fuel ratio was varied from 7.0 to 15.3. Numerical simulation with a detailed description of the complex kinetics of ethane oxidation was performed. The necessity of taking into account heterogeneous processes on the reactor surface under these conditions was shown and a method for this was proposed. When the detailed gas-phase mechanisms of ethane oxidation are complemented with stages describing heterogeneous processes on the surface of the quartz reactor, the results of numerical modeling are in good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

One of the most active and high-selective catalytic systems for oxidative dehydrogenation of ethane is the MoVNbTeOx catalyst. However, this catalytic system has the low thermal stability and is prone to deactivation at temperatures above 350 °C. At the first time it was proposed to use oxygen ((Tcr = –119 °C, Pcr = 48 atm) and ethane (Tcr = 32 °C, Pcr = 51 atm) in supercritical state in the oxidative dehydrogenation process. Carrying out the process at supercritical conditions (T = 240–300 °C, P = 60–100 atm) leads to high selectivity up to 90% for ethylene under growth conversion of ethane and oxygen. At the same time, it manages to keep M1 phase crystallinity unchanged throughout the experiment (more than 40 h). Dependences of ethylene productivity on pressure (Reaction conditions: T = 280 °C, C2H6:O2:N2 = 31:23:46, 2 g of catalyst, the density of the reagent mixture varies from 0.65 (at 1 atm) to 63.15 kg/m3 (at 100 atm) [ABSTRACT FROM AUTHOR]

The conversion of methane–ethane, methane–ethylene, hydrogen–ethane, and hydrogen–ethylene mixtures on an electrically heated resistive fechral catalyst is studied. In the course of conversion, the catalyst surface is covered with graphite-like carbon deposits that have an additional catalytic effect resulting in the formation of C3 and C4 hydrocarbons. The latter are apparently formed with participation of ethylene formed from ethane. Hydrogen suppresses coking on the catalyst's surface and reduces the yield of C3 and C4 hydrocarbons. [ABSTRACT FROM AUTHOR]

• New experiemental IDTs for binary bleneded C 2 –C 3 alkanes/alkene are presented. • Newly developed NUIGMech1.1 is evaluated versus the newly taken IDTs. • NUIGMech1.1 predicts the IDTs accurately over the wide range of studied conditions. • Some correlations were derived based on NUIGMech1.1. • The correlations satisfactorily anticipated IDTs data within the studied range. In this work, the ignition delay time characteristics of C 2 – C 3 binary blends of gaseous hydrocarbons including ethylene/propane and ethane/propane are studied over a wide range of temperatures (750 – 2000 K), pressures (1 – 135 bar), equivalence ratios (φ = 0.5 – 2.0) and dilutions (75 – 90%). A matrix of experimental conditions is generated using the Taguchi (L 9) approach to cover the range of conditions for the validation of a chemical kinetic model. The experimental ignition delay time data are recorded using low- and high-pressure shock tubes and two rapid compression machines (RCM) to include all of the designed conditions. These novel experiments provide a direct validation of the chemical kinetic model, NUIGMech1.1, and its performance is characterized via statistical analysis, with the agreement between experiments and model being within ~ 26.4% over all of the conditions studied, which is comparable with a general absolute uncertainty of the applied facilities (~ 20%). Sensitivity and flux analyses allow for the key reactions controlling the ignition behavior of the blends to be identified. Subsequent analyses are performed to identify those reactions which are important for the pure fuel components and for the blended fuels, and synergistic/antagonistic blending effects are therefore identified over the wide range of conditions. The overall performance of NUIGMech1.1 and the correlations generated are in good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

Three samples with different silica-alumina ratios (40, 500 and 1500) were synthesized to reveal the effect of high silica-alumina ratios on the selectivity of C 2 H 6 /C 2 H 4. The results show that C 2 H 6 /C 2 H 4 selectivity increase as the silica-alumina ratios increases. Both experimental and simulation studies showed that pure silica zeolite (SiO 2 /Al 2 O 3 = 1500) exhibited excellent separation performance for C 2 H 6 /C 2 H 4. It remains unaffected even in the presence of H 2 O, making it a highly promising adsorbent for selective ethane adsorption. [Display omitted] • C 2 H 6 and C 2 H 4 adsorption was investigated on samples with different silica-alumina ratios. • The selectivity of C 2 H 6 /C 2 H 4 increase as the silica-alumina ratios increases. • Pure silica sample exhibits excellent C 2 H 6 /C 2 H 4 separation performance. • The separation performance remains unaffected even in the presence of H 2 O. The economically efficient separation of ethane (C 2 H 6)/ethylene (C 2 H 4) presents challenges in the petrochemical industry, and the use of traditional adsorbents zeolite provides a reliable guarantee for maintaining the economic viability of adsorption separation technology. In this study, we investigate the impact of different silica-alumina ratios (SiO 2 /Al 2 O 3 = 40, 500, and 1500) of high silica zeolites ZSM-11 on the C 2 H 6 /C 2 H 4 separation performance to develop efficient C 2 H 6 selective adsorbents. The results show that the C 2 H 6 adsorption capacity and C 2 H 6 /C 2 H 4 selectivity of ZSM-11 increase as the silica-alumina ratios increases. The pure silica zeolite (ZSM-11(1500)) exhibits the highest adsorption capacity for C 2 H 6 (59.19 cm3/g) and the highest selectivity for C 2 H 6 /C 2 H 4 (2.04), which were superior to ultra-high silica sample (ZSM-11(500)) (55.06 cm3/g and 1.62, respectively) and high silica sample (ZSM-11(40)) (47.28 cm3/g and 1.23, respectively), at 273 K and 1 bar. The mixed gas breakthrough experiments results show that pure silica sample has outstanding C 2 H 6 /C 2 H 4 separation ability. The PSA simulation calculated data demonstrating promising potential for industrial applications. Importantly, this separation performance remains unaffected even in the presence of H 2 O. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanosized NiO particles dispersed on titanium pyrophosphate were obtained. • The catalytic performance of NiO/TiP 2 O 7 is significantly improved compared to bulk NiO. • The catalytic activity increases with increasing Ni loading. • Ethylene selectivity parallels the catalyst basicity which increases with Ni loading. • Catalysts show good stabilities on stream at temperatures lower than 450 °C. Titanium pyrophosphate-supported NiO catalysts with different Ni loadings in the range from 10 to 26 wt. % were prepared by wet impregnation, characterized by nitrogen adsorption at −196 °C, ICP-OES, XRD, CO 2 -TPD and H 2 -TPR techniques and tested in ethane oxydehydrogenation (ODH) in the temperature range from 350 to 450 °C. With increasing the Ni loading, the surface area of the catalysts decreased while the NiO particle size, the basicity and the reducibility increased strongly influencing their catalytic performance. Increasing the Ni loading boosted ethane conversion that reached 36 and 50 % at 425 and 450 °C, respectively, for the highest nickel loading catalyst. Ethylene was the main reaction product for all the catalysts. The ethylene selectivity at isoconversion increases with increasing the Ni loading. The stability of the catalysts was studied at a temperature as high as their calcination temperature, i.e. 450 °C, and at lower temperature. [ABSTRACT FROM AUTHOR]

Owing to the similar physicochemical properties between ethane (C2H6) and ethylene (C2H4), obtaining polymerization-grade C2H4 (≥99.95% pure) is still tricky problem in the petrochemical industry. Here, we report a robust scandium-based metal-organic framework (ScBPDC), which is connected by oxygen-rich phenyl ligand with exceptionally high thermal stability (up to 873 K) and capacity of C2H6 (4.94 mmol/g at 100 kPa and 283 K), exhibiting superior separation performance of C2H6/C2H4 mixture (the IAST selectivity is up to 1.7 at 283 K). Importantly, ScBPDC can produce 8.96 L/kg C2H4 with ≥99.99% purity while the C2H4/C2H6 (50:50, v/v) as the mixture injection and the low isosteric heat of ScBPDC (16.4 kJ/mol for C2H6) validates the facility of adsorbent regeneration. Furthermore, theoretical calculations demonstrate the C2H6 molecules are trapped in the nonpolar pore surface via C-H⋯π and C-H⋯O interactions between multiple hydrogen atoms of C2H6 and the host framework. [ABSTRACT FROM AUTHOR]

The Energy, Environment, Science and Technology (EES&T) Directorate of the Idaho National Laboratory (INL) launched an advanced manufacturing platform in 2015, which has evolved into a national laboratory initiative across all INL directorates as of 2018. Thus, all three INL Directorates, including nuclear and cyber security, are engaged in a unified advanced manufacturing strategy. The ultimate goal of this initiative is to increase the economic competitiveness of energy-generation systems, security systems, structural components, and industrial chemical processes by advancing the knowledge that supports improved fabrication and manufacturing technologies. To move this innovation forward, INL is designing, building and testing what is not possible with traditional manufacturing techniques. The development of advanced manufacturing technologies has the potential to significantly expand the design options of the solutions to manufacturing problems that have been challenging the industrial sector for years. • This article will describe the focus areas that INL has decided to address in the industrial chemical processes thrust. In this regards, high energy-consuming and low energy-efficient processes are of our top concerns. The manufacturing of olefins from natural gas components namely methane and ethane presents these challenges and give us the opportunity to address it as a first priority in the INL's recently established advanced manufacturing initiative. • One may envision the conversion of alkanes to alkenes as the first step of functionalization, i.e. creating unsaturation sites that convert low reactive alkanes into more reactive building units. • This new vision of Lego-like chemical manufacturing is a paradigm shift from the historical chemical manufacturing approach of starting from heavy crude and cracking down to smaller hydrocarbon building blocks. INL's new chemical manufacturing approach leads to significant energy saving and reduction of waste products. [ABSTRACT FROM AUTHOR]

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• Mo-V-Te-Nb-O mixed oxides have been prepared successfully by reflux method by optimizing the synthesis parameters. • These catalysts present high activity and selectivity for partial oxidation of propane to acrylic acid. • These Mo-V-Te-Nb-O catalysts are active and selective for the ethane oxidative dehydrogenation. • The catalytic behavior is strongly related to the presence of orthorhombic M1 phase. The investigation here presented studies the effect of the synthesis temperature (from 80 to 110 °C) and the time (from 1 to 4 days) employed to precipitate catalyst precursors by reflux method, on the physic-chemical and the catalytic properties of the resulting Mo-V-Te-Nb mixed oxide catalysts for both propane partial oxidation into acrylic acid and ethane oxidative dehydrogenation (ODH) to ethylene. The insight obtained has allowed an important optimization of the not commonly used reflux method to prepare Mo-V-Te-Nb oxide materials with competitive catalytic performance. The yields achieved overcome those from optimized catalysts prepared by conventional hydrothermal method, and approach those reached with catalysts prepared using the "slurry method". The optimum rise for the synthesis temperature is found as a key factor for the reflux method. It allows access to an increased vanadium content into the reflux precipitate, which favors the formation of a pseudo-amorphous Mo-V-Te-Nb oxometallate. This precipitate behaves as a precursor for the crystallization, during the solid-state activation step at high-temperature (600 °C/N 2), of the structure type (TeO) 2 M 20 O 56 (M = Mo, V, Nb), key for the selective conversion of propane or ethane. On the other hand, for the optimum temperature of synthesis, i.e. 110 °C, higher synthesis time of the precursor leads to smaller crystal sizes in the final catalyst (higher specific surface areas) and lowers the average oxidation state of vanadium from V+5 to V+4, which significantly enhances the catalytic behavior. [ABSTRACT FROM AUTHOR]

Ethylene remains one of the most valuable chemical feedstocks. Currently the industrial conversion of ethane to ethylene is achieved largely by steam cracking. The catalytic, highly exothermic oxidative dehydrogenation (ODH) of ethane with O2 is a challenging alternative that has been extensively studied on the laboratory scale. Here we investigate the possibility of using disulfur (S2) vapor as a thermodynamically "soft" oxidant for catalytically converting ethane to ethylene ("SODH"). Investigating a series of four catalysts we report a maximum ethylene yield of 76 % over an earth‐abundant FeSx‐based catalyst (maximum 90.2 % C2H4 selectivity at 820 °C). Yield and selectivity are stable for 50 hours on stream. The SODH rate law is 1st order in ethane and 1/2 order in S2, supporting a proposed Mars van Krevelen‐like mechanism at temperatures <700 °C. Furthermore, conversion and selectivity become insensitive to catalyst identity at temperatures >860 °C, suggesting the intrusion of radical pathways. [ABSTRACT FROM AUTHOR]

Cometabolic biodegradation of 1,4-dioxane (dioxane) in the presence of primary substrates is a promising strategy for treating dioxane at environmentally relevant concentrations. Seven aqueous amendments (i.e., tetrahydrofuran (THF), butanone, acetone, 1-butanol, 2-butanol, phenol and acetate) and five gaseous amendments (i.e., C1–C4 alkanes and ethylene) were evaluated as the primary substrates for dioxane degradation by mixed microbial consortia. The aqueous amendments were tested in microcosm bottles and the gaseous amendments were tested in a continuous-flow membrane biofilm reactor with hollow fibers pressurized by the gaseous amendments. Ethane was found to be the most effective gaseous substrate and THF was the only aqueous substrate that promoted dioxane degradation. A diverse microbial community consisting of several putative dioxane degraders—Mycobacterium, Flavobacterium and Bradyrhizobiaceae—were enriched in the presence of ethane. This is the first study showing that ethane was the most effective substrate among the short-chain alkanes and it promoted dioxane degradation by enriching dioxane-degraders that did not harbor the well-known dioxane/tetrahydrofuran monooxygenase. [ABSTRACT FROM AUTHOR]

[Display omitted] • Highly dense methyl groups were incorporated into cavity-like pores in stable MOF. • Both C 2 H 6 uptake and C 2 H 6 /C 2 H 4 selectivity increased with methyl group density. • UiO-66-2Me exhibited among the highest C 2 H 6 /C 2 H 4 selectivity (2.73) reported. • UiO-66-2Me demonstrated facile regeneration and high hydrothermal stability. • UiO-66-2Me is a promising adsorbent for C 2 H 6 /C 2 H 4 separation. The development of efficient adsorbents for C 2 H 6 /C 2 H 4 separation is an important and challenging issue for the economical production of high-purity ethylene, a valuable precursor for the petrochemical industry. We developed an efficient adsorbent for C 2 H 6 /C 2 H 4 separation by incorporating highly dense methyl groups into a highly stable UiO-66 framework with "cavity-like" pores. Remarkably, UiO-66-2Me exhibited large C 2 H 6 uptake at 1 bar (2.15 mmol/g) and significantly high C 2 H 6 /C 2 H 4 IAST selectivity (2.93), which is one of the highest values reported. From a combined experiments and computational study, we verified that the observed high selectivity was originated from the specific interaction between C 2 H 6 and multiple methyl groups in the cavity-like pores. Moreover, UiO-66-2Me showed high C 2 H 6 /C 2 H 4 selectivity (2.05) even under the dynamic mixture flow condition, easy regeneration and good hydrothermal and thermal stabilities. These results suggest that incorporating highly dense methyl groups into a stable MOF with cavity-like pores is a promising method for developing an efficient adsorbent for C 2 H 6 /C 2 H 4 separation. [ABSTRACT FROM AUTHOR]

[Display omitted] • C 2 H 4 /C 2 H 6 separation was studied using highly permeable ZIF-8 membranes. • The membrane temperatures were varied from −30 to 100 °C for separation. • A high C 2 H 4 permeance of 8.1 × 10−7 mol/(m2·s·Pa) was observed at −30 °C. Ethylene/ethane separation is a critical and energy-consuming process in the chemical industry due to the similar properties of the compounds and the great need of ethylene for e.g., polymer production. Many materials have been studied for their implementation as membranes as an energetically favorable alternative to conventional distillation and adsorption processes. Metal-organic frameworks (MOF) have revealed promising properties as highly permeable and selective membranes. Among the most studied and promising MOF candidates is ZIF-8, known for its thermal stability and small pores connected by narrow-sized windows. In this work, we present an analysis of the influence of parameters such as temperature, feed pressure and feed flowrate on the separation of ethylene/ethane through a thin ZIF-8/alumina disc membrane. We observed that the temperature has a significant effect on the separation. The ethylene permeance increased with decreased temperature and reached 8.1 × 10−7 mol/(m2·s·Pa) at −30 °C. At this temperature, the ethylene/ethane selectivity was 2.5. The study concluded with a considerable enhancement of the permeance of ZIF-8 membranes for ethylene/ethane separations, while maintaining a good selectivity compared to the reported values in the literature. The results have important implications for the development of more cost-effective and energy-efficient membrane-based separation technologies for ethylene purification. [ABSTRACT FROM AUTHOR]