Reversed ethane/ethylene adsorption in a metal–organic framework via introduction of oxygen

Separation of ethane from ethylene is a very important but challenging process in the petrochemical industry.Finding an alternative method would reduce the energy needed to make 170 million tons of ethylene manufactured worldwide each year.Adsorptive separation using C2H6-selective porous materials to directly produce high-purity C2H4 is more energy-efficient.We herein report the"reversed C2H6/C2H4 adsorption"in a metal–organic framework Cr-BTC via the introduction of oxygen on its open metal sites.The oxidized Cr-BTC(O2)can bind C2H6 over C2H4 through the active Cr-superoxo sites,which was elucidated by the gas sorption isotherms and density functional theory calculations.This material thus exhibits a good performance for the separation of 50/50 C2H6/C2H4 mixtures to produce 99.99%pure C2H4 in a single separation operation.

Boosting kinetic separation of ethylene and ethane on microporous materials via crystal size control

The adsorptive separation of C_(2)H_(4)and C_(2)H_(6),as an alternative to distillation units consuming high energy,is a promising yet challenging research.The great similarity in the molecular size of C_(2)H_(4)and C_(2)H_(6)brings challenges to the regulation of adsorbents to realize efficient dynamic separation.Herein,we reported the enhancement of the kinetic separation of C_(2)H_(4)/C_(2)H_(6)by controlling the crystal size of ZnAtzPO_(4)(Atz=3-amino-1,2,4-triazole)to amplify the diffusion difference of C_(2)H_(4)and C_(2)H_(6).Through adjusting the synthesis temperature,reactant concentration,and ligands/metal ions molar ratio,ZnAtzPO4 crystals with different sizes were obtained.Both single-component kinetic adsorption tests and binary-component dynamic breakthrough experiments confirmed the enhancement of the dynamic separation of C_(2)H_(4)/C_(2)H_(6)with the increase in the crystal size of ZnAtzPO_(4).The separation selectivity of C_(2)H_(4)/C_(2)H_(6)increased from 1.3 to 98.5 with the increase in the crystal size of ZnAtzPO_(4).This work demonstrated the role of morphology and size control of adsorbent crystals in the improvement of the C_(2)H_(4)/C_(2)H_(6)kinetic separation performance.

Enhanced ethane/ethylene separation based on metal regulation in zeolitic imidazolate frameworks

The acquisition of polymer-grade(≥99.95%)C_(2)H_(4) poses a challenge due to the presence of ethane(C_(2)H_(6))having similar physical and chemical properties.Consequently,the one-step purification of C_(2)H_(4) becomes a crucial and demanding process.In this study,we synthesized ZIF-78 with a GME configuration using different metal sources(Zn,Co).Both substances have been identified as ethane-selective adsorbents with excellent thermal stability.The Brunauer Emmett Teller(BET)surface area of ZIF-78-Co(748 m^(2)/g)surpasses that of ZIF-78-Zn(585 m^(2)/g),and the former exhibits a higher Q_(st) value for C_(2)H_(6),resulting in enhanced adsorption capacity for C_(2)H_(6)(50.61 cm^(3)/g)and selectivity for C_(2)H_(6)/C_(2)H_(4)(1.71)compared to ZIF-78-Zn(48.97 cm^(3)/g,1.46)at 298 K and 1 bar.Grand Canonical Monte Carlo(GCMC)calculations indicate that C_(2)H_(6) has a stronger interaction with the ZIF-78-Co framework.Breakthrough experiments for the C_(2)H_(6)/C_(2)H_(4)(50:50,V/V)mixture at 298 K and 1 bar demonstrate that ZIF-78-Co achieves separation in approximately 5 min/g,outperforming ZIF-78-Zn.And the separation time for ZIF-78-Co in the C_(2)H_(6)/C_(2)H_(4)(10:90,V/V)mixture is 9 min/g.Furthermore,ZIF-78-Co exhibits excellent structural stability,thermal stability,water stability,and acid-base stability.Therefore,it holds promising prospects for practical industrial separation.Additionally,we hope that our findings inspire further experimentation on alternative metal ethane adsorbents.

Reaction pathways and selectivity in the chemo-catalytic conversion of cellulose and its derivatives to ethylene glycol:A review

Biomass-to-ethylene glycol is an effective means to achieve high-value utilisation of cellulose but is hindered by low conversion efficiency and poor catalyst activity and stability.Glucose and cellobiose are derivatives of cellulose conversion to ethylene glycol,and it is found that studying the reaction process of both can help to understand the reaction mechanism of cellulose.It is desirable to develop a reusable,highly active catalyst to convert cellulose into ethylene glycol.This ideal catalyst might have one or more active sites described the conversion steps above.Here,we discuss the catalyst development of celluloseto-ethylene glycol,including tungsten,tin,lanthanide,and other transition metal catalysts,and special attention is given to the reaction mechanism and kinetics for preparing ethylene glycol from cellulose,and the economic advantages of biomass-to-ethylene glycol are briefly introduced.The insights given in this review will facilitate further development of efficient catalysts,for addressing the global energy crisis and climate change related to the use of fossil fuels.

Novel sandwich structured glass fiber Cloth/Poly(ethylene oxide)-MXene composite electrolyte

Recently,poly(ethylene oxide)(PEO)-based solid polymer electrolytes have been attracting great attention,and efforts are currently underway to develop PEO-based composite electrolytes for next generation high performance all-solid-state lithium metal batteries.In this article,a novel sandwich structured solid-state PEO composite electrolyte is developed for high performance all-solid-state lithium metal batteries.The PEO-based composite electrolyte is fabricated by hot-pressing PEO,LiTFSI and Ti_(3)C_(2)T_(x) MXene nanosheets into glass fiber cloth(GFC).The as-prepared GFC@PEO-MXene electrolyte shows high mechanical properties,good electrochemical stability,and high lithium-ion migration number,which indicates an obvious synergistic effect from the microscale GFC and the nanoscale MXene.Such as,the GFC@PEO-1 wt%MXene electrolyte shows a high tensile strength of 43.43 MPa and an impressive Young's modulus of 496 MPa,which are increased by 1205%and 6048%over those of PEO.Meanwhile,the ionic conductivity of GFC@PEO-1 wt%MXene at 60℃ reaches 5.01×10^(-2) S m^(-1),which is increased by around 200%compared with that of GFC@PEO electrolyte.In addition,the Li/Li symmetric battery based on GFC@PEO-1 wt%MXene electrolyte shows an excellent cycling stability over 800 h(0.3 mA cm^(-2),0.3 mAh cm^(-2)),which is obviously longer than that based on PEO and GFC@PEO electrolytes due to the better compatibility of GFC@PEO-1 wt%MXene electrolyte with Li anode.Furthermore,the solid-state Li/LiFePO_(4) battery with GFC@PEO-1 wt%MXene as electrolyte demonstrates a high capacity of 110.2–166.1 mAh g^(-1) in a wide temperature range of 25–60C,and an excellent capacity retention rate.The developed sandwich structured GFC@PEO-1 wt%MXene electrolyte with the excellent overall performance is promising for next generation high performance all-solid-state lithium metal batteries.

Surface Acidity/Basicity and Catalytic Reactivity of CeO2/7-Al2O3 Catalysts for the Oxidative Dehydrogenation of Ethane with Carbon Dioxide to Ethylene

Dehydrogenation of ethane to ethylene in CO_2 was investigated overCeO_2/γ-Al_2O_3 catalysts at 700℃ in a conventional flow reactor operating at atmosphericpressure. XRD, BET and microcalori-metric adsorption techniques were used to characterize thestructure and surface acidity/basicity of the CeO_2/γ-Al_2O_3 catalysts. The results show that thesurface acidity decreased while the surface basicity increased after the addition of CeO_2 toγ-Al_2O_3. Accordingly, the activity of the hydrogenation reaction of CO_2 increased, which mightbe responsible for the enhanced conversion in the dehydrogenation of ethane to ethylene. The highestethane conversion obtained was about 15% for the 25%CeO_2/γ-Al_2O_3. The selectivity to ethylenewas high for all the CeO_2, γ-Al_2O_3 and CeO2/γ-Al_2O_3 catalysts.

Polyvinyl Acetate and Vinyl Acetate-Ethylene Hybrid Adhesive: Synthesis, Characterization, and Properties

The goal is to develop a hybrid IPN network of polyvinyl acetate (PVAc) and ethylene-vinyl acetate (VAE). In this research work, the vinyl acetate (VAc)/ VAE hybrid emulsion and polyvinyl acetate emulsion (PVAc) were effectively synthesized. Emulsions with various characteristics have been developed by adjusting the weight ratios between the vinyl acetate monomer and the VAE component. The impacts on the mechanical, thermal, and physical properties of the films were investigated using tests for pencil hardness, tensile shear strength, pH, contact angle measurement, differential scanning calorimetry (DSC), and viscosity. When 5.0 weight percent VAE was added, the tensile shear strength in dry conditions decreased by 18.75% after a 24-hour bonding period, the heat resistance decreased by 26.29% (as per WATT 91) and the tensile shear strength decreased by approximately 36.52% in wet conditions (per EN 204). The pristine sample’s results were also confirmed by the contact angle test. The interpenetrating network (IPN) formation in hybrid PVAc emulsion as primary bonds does not directly attach to PVAc and VAE chains. The addition of VAE reduced the mechanical properties (at dry conditions) and heat resistance as per WATT 91. Contact angle analysis demonstrated that PVAc adhesives containing VAE had increased water resistance when compared to conventional PVA stabilised PVAc homopolymer-based adhesives. When compared to virgin PVAc Homo, the water resistance of the PVAc emulsion polymerization was enhanced by the addition of VAE.

Synergistic Effects of Nitrogen Amendments and Ethylene on Atmospheric Methane Uptake under a Temperate Old-growth Forest

An increase in atmospheric nitrogen （N） deposition can promote soil acidification, which may increase the release of ethylene （C2H4） under forest floors. Unfortunately, knowledge of whether increasing N deposition and C2H4 releases have synergistic effects on soil methane （CH4） uptake is limited and certainly deserves to be examined. We conducted some field measurements and laboratory experiments to examine this issue. The addition of （NH4）2SO4 or NH4Cl at a rate of 45 kg N ha-1 yr-1 reduced the soil CH4 uptake under a temperate old-growth forest in northeast China, and there were synergistic effects of N amendments in the presence of C2H4 concentrations equal to atmospheric CH4 concentration on the soil CH4 uptake, particularly in the NH4Cl-treated plots. Effective concentrations of added C2H4 on the soil CH4 uptake were smaller in NH＋4 -treated plots than in KNO3-treated plots. The concentration of ca 0.3 μl C2H4 L-1 in the headspace gases reduced by 20% soil atmospheric CH4 uptake in the NH4Cl-treated plots, and this concentration was easily produced in temperate forest topsoils under short-term anoxic conditions. Together with short-term stimulating effects of N amendments and soil acidification on C2H4 production from forest soils, our observations suggest that knowledge of synergistic effects of NH＋4 , rather than NO3- , amendments and C2H4 on the in situ soil CH4 uptake is critical for understanding the role of atmospheric N deposition and cycling of C2H4 under forest floors in reducing global atmospheric CH4 uptake by forests. Synergistic functions of NH4＋ -N deposition and C2H4 release due to soil acidification in reducing atmospheric CH4 uptake by forests are discussed.

Promoted catalytic performances of highly dispersed V-doped SBA-16 catalysts for oxidative dehydrogenation of ethane to ethylene

V-doped SBA-16 catalysts (V-SBA-16) with 3D nanocage mesopores have been successfully synthesized by a modified one-pot method under weak acid condition. The obtained materials were characterized by means of small angle XRD, N2adsorption–desorption, TEM, UV–Vis and UV-Raman spectroscopy. These characterization results indicated that well-order mesoporous structures were maintained even at higher vanadium loadings and high concentration of VOxspecies were incorporated into the framework of SBA-16 support. The catalytic performances of V-SBA-16, V/SBA-16 and V/SiO2catalysts were comparatively investigated for the oxidative dehydrogenation of ethane to ethylene. The highest selectivity to ethylene of 63.3% and ethylene yield of 25.6% were obtained over 1.0V-SBA-16 catalyst. The superior catalytic performance of V-SBA-16 catalysts could be attributed to the presence of isolated framework VOxspecies, the unique structure of SBA-16 support and weak acidity. Moreover, V/SiO2catalyst exhibited relatively poor catalytic activity duo to the formation of V2O5nanoparticles on the surface of SiO2support and the low dispersion of VOxspecies. These results indicated that the catalytic performances of the studied catalysts were strongly dependent on the vanadium loading, the nature and neighboring environment of VOxspecies and the structure of support. ? 2016

Effect of methane co-feeding on the selectivity of ethylene produced from oxidative dehydrogenation of ethane with CO_2 over a Ni-La/SiO_2 catalyst

A Ni-La/SiO2 catalyst was prepared through the incipient wetness impregnation method and tested in the oxidative dehydrogenation of ethane （ODHE） with CO2. The fresh and used catalysts were characterized by XRD and SEM techniques. The Ni-La/SiO2 catalyst exhibited catalytic activity for the oxidative dehydrogenation of ethane, but with low ethylene selectivity in the absence of methane. The selectivity to ethylene increased with increasing molar ratio of methane in the feed. The carbon deposited on the catalyst surface in the sole ODHE with CO2 was mainly inert carbon, while much more filamentous carbon was formed in the presence of methane. The filamentous carbon was easy to be removed by CO2, which might play a role in improving the conversion of ethane to ethylene. The introduction of methane might affect the equilibrium of the CO2 reforming of ethane and the ODHE with CO2. As a consequence, the synthesis gas produced from CO2 reforming of methane partly inhibited the reaction of ethane and promoted the ODHE with CO2, thus increasing the selectivity of ethylene.

Study of Adsorptive Ethylene/Ethane Separation with Ag^+-Exchanged Resins via π-Complexation

Ag^+-exchanged resins are prepared and studied for ethylene/ethane separation by adsorption.On Ag^+-exchanged S9,at 25℃ and 0.1013MPa,the equilibrium adsorbed amount for C2H4 is 0.992mmol·g^-1,and the adsorption ratio for C2H4/C2H6 is 3.56.The adsorption capacity can be restored almost completely at 25℃ and 75℃,and the desorption residual amount is less than 0.01mmol·g^-1.For the adsorption consisting of physical adsorption and π-complexation with energy heterogeneity,the equilibrium data are correlated with Langmuir-Freundlich isotherm equation.Furthermore,the heat of adsorption and the overall diffusion time constants are calculated from the experimental datal.Considering all the adsorption characteristics,the application potential for industrial adsorption process is discussed.

A Green Process for High-Concentration Ethylene and Hydrogen Production from Methane in a Plasma-Followed-by-Catalyst Reactor

A green process for the oxygen-free conversion of methane to high-concentration ethylene and hydrogen in a plasma-followed-by-catalyst （PFC） reactor is presented. Without any catalysts and with pure methane used as the feed gas, a stable kilohertz spark discharge leads to an acetylene yield of 64.1%, ethylene yield of 2.5% and hydrogen yield of 59.0% with 80.0% of methane conversion at a methane flow rate of 50 cm^3/min and a specific input energy of 38.4 kJ/L. In the effluent gas from a stable kilohertz spark discharge reactor, the concentrations of acetylene, ethylene and hydrogen were 18.1%, 0.7% and 66.9%, respectively. When catalysts Pd-Ag/SiO2 were employed in the second stage with discharge conditions same as in the case of plasma alone, the PFC reactor provides an ethylene yield of 52.1% and hydrogen yield of 43.4%. The concentrations of ethylene and hydrogen in the effluent gas from the PFC reactor were found to be as high as 17.1% and 62.6%, respectively. Moreover, no acetylene was detected in the effluent gas. This means that a high concentration of ethylene and oxygen-free hydrogen can be co-produced directly from methane in the PFC reactor.

π-Complexation Mesoporous Adsorbents Cu-MCM-48 for Ethylene-Ethane Separation

苯和 triisopropylbenzene 吸着能力和为 MCM-41 和 MCM-48 的几件样品的吸附的率被比较。结果显示为有类似的毛孔直径的样品， MCM-41 比 MCM-48 为二烃有约 30% 更多的全部的能力。从苯能力大小估计的毛孔尺寸同意很好，那些从氩吸附计算了。用苯能力大小做的估计显示为 MCM-41，取样毛孔墙的厚度是约 8 并且独立于毛孔直径；MCM-48 样品的毛孔墙厚度被估计稍微更大，约 10。为所有样品的吸着率被发现，因此没有结论能有关亲戚被得出的散开限制而非 mesopore 散开通过这些样品的 mesoporous 隧道特征苯的散开评估的 macropore 指示。

Effect of Zeolite 5A Particle Size on Its Performance for Adsorptive Separation of Ethylene/Ethane

The adsorptive separation of ethylene from ethane exhibits a less energy-intensive-alternative technique with development potential among all processes for separation of ethylene/ethane currently. In this approach, zeolite 5 A with different particle sizes ranging from 3 340 nm to 440 nm was prepared by hydrothermal synthesis. The effect of particle size on the adsorptive separation performance of zeolite 5 A was investigated. The results show that the particle size has a significant effect on the ethylene IAST(Ideal Adsorbed Solution Theory) selectivity of zeolite 5 A. The zeolite 5 A with a particle size of 710 nm demonstrated the highest ethylene selectivity(5.6). The relatively high crystallinity of zeolite 5 A is in favor of massive adsorption capacities of ethylene and ethane.

Oxygen-Free Conversion of Methane to Ethylene in a Plasma-Followed-by-Catalyst (PFC) Reactor

Oxygen-free conversion of methane to ethylene was investigated in a two-stage plasma-followed-by-catalyst （PFC） reactor. In the absence of catalyst, pulsed spark discharges and pulsed corona discharges were compared for methane conversion. The results showed that methane was mainly converted to acetylene, but pulsed spark discharges exhibited distinct advantages over the pulsed corona discharges in methane conversion. Thereby, pulsed spark discharges were employed and followed by Ag-Pd/SiO2 catalyst for achieving ethylene as a target product in the PFC reactor. Using the PFC reactor, a steady single-pass ethylene yield of 57% was obtained at a rate of methane conversion of 74%.

Complexation Properties and Synthesis of 1,2-Bis(2 ,2' -bipyridinyl)ethylene and 1,2-Bis(2,2' -bipyridinyl)ethane Ligands with Cu(I)

l,2-Bis(2,2'-bipyridinyl)ethylene(1) ligand was synthesized by Wittig-Horner reaction and 1, 2-Bis(2, 2'-bipyridinyl)ethane(2) ligand(which can be obtained via another route ) was prepared by hydrogenation of (1). The formation of complexes of (1) and (2) with copper (I) has been studied. The influence of the different bridge chains (CH =CH, CH2CH2) on complexation is discussed on the basis of 1H NMR spectra. Keywords Dipyridine aldehyde, Dipyridine derivative, Copper complex

Experimental study of partially decoupled oxidation of ethane for producing ethylene and acetylene

With increasing amount of unconventional natural gas,the production of ethane,propane and other low alkanes continues to increase.In our previous works,a partially decoupled process(PDP) was proposed for conversion of ethane based on numerical simulations,which showed higher acetylene and ethylene selectivities than the original partial oxidation process.In the current work,the PDP of ethane for producing acetylene and ethylene was studied experimentally to verify the PDP concept.In the PDP of ethane,coke-oven gas or other cheap gas combusts with stoichiometric oxygen as heat carrier,and ethane is mixed with the heat carrier and undergoes pyrolysis at high temperatures.The jet-in-cross-flow(JICF) reactor was designed and manufactured to realize the PDP.A positioning device of 0.1 mm accuracy and a mass spectrometer were used to measure the spatial profiles of the species concentrations.The maximum combined yield(52.7%) of acetylene and ethylene was obtained even at the condition of heat loss,confirming that the PDP of ethane was advantageous over the partial oxidation process and at least comparable to the steam cracking process.

Lanzhou Petrochemical Company’s Ethane-to-Ethylene Demonstration Project Becomes Operational

On August 3,2021,the Changqing ethane-to-ethylene project owned by the PetroChina Lanzhou Petrochemical Company(LPC)had been put on stream to crank out qualified ethylene product.The construction of this project,located in the Yuheng Industrial Park of Yulin city,Shaanxi province,was kicked off in June 2019,with the total investment amounting to around 10.4 billion RMB.The project mainly consists of an 800 kt/a unit for manufacturing ethylene from ethane cracking,the downstream two 400 kt/a polypropylene units,and a 20 kt/a unit for manufacture of 1-hexene.

THE STUDY OF THE NON-STEADY KINETICS OF THE OXYDEHYDROGENATION OF ETHANE TO ETHYLENE OVER THE CATALYST OF Mo-V-Nb/Al_2O_3 BY THE TECHNIQUE OF TEMPERATURE PROGRAMMED TRANSIENT RESPONSE AND ELECTRIC CONDUCTIVITY

In this paper, instead of with the more expensive Fourier Transform Infrared Spectrometer(FTIR) a new technique of Temperature Programmed Transient Response(TP-TR) has been used with gas chromatography. Therefore, the TP-TR will be applied more widespreadly than ever before. With the technique of TP-TR and electric conductivity, the study is on the reaction mechanism and the adsorption behavior of the reactants and products to the present catalyst Mo-V-Nb/Al_2O_3 in the reaction from ethane through oxydehydrogenation to ethylene as the product. By Range-Kutta-Gill and Margarat methods, the kinetic parameters of the reaction elementary steps (i.e. rate constants, active energies and frequency factors) have been evaluated. The mathematical treatment coincides with the experimental results.