An efficient and stable Cu/SiO_2 catalyst for the syntheses of ethylene glycol and methanol via chemoselective hydrogenation of ethylene carbonate

The efficient synthesis of methanol and ethylene glycol via the chemoselective hydrogenation of ethylene carbonate（EC） is important for the sustainable utilization of CO_2 to produce commodity chemicals and fuels. In this work, a series of β-cyclodextrin-modified Cu/SiO_2 catalysts were prepared by ammonia evaporation method for the selective hydrogenation of EC to co-produce methanol and ethylene glycol. The structure and physicochemical properties of the catalysts were characterized in detail by N_2 physisorption, XRD, N_2O titration, H_2-TPR, TEM, and XPS/XAES. Compared with the unmodified 25 Cu/SiO_2 catalyst, the involvement of β-cyclodextrin in 5β-25 Cu/SiO_2 could remarkably increase the catalytic activity—excellent activity of 1178 mgEC g_（cat）^（–1） h^（–1） with 98.8%ethylene glycol selectivity, and 71.6% methanol selectivity could be achieved at 453 K. The remarkably improved recyclability was primarily attributed to the remaining proportion of Cu~＋/（Cu^0＋Cu~＋）. Furthermore, the DFT calculation results demonstrated that metallic Cu^0 dissociated adsorbed H_2, while Cu~＋ activated the carbonyl group of EC and stabilized the intermediates. This study is a facile and efficient method to prepare highly dispersed Cu catalysts—this is also an effective and stable heterogeneous catalyst system for the sustainable synthesis of ethylene glycol and methanol via indirect chemical utilization of CO_2.

Effect of copper loading on texture,structure and catalytic performance of Cu/SiO_2 catalyst for hydrogenation of dimethyl oxalate to ethylene glycol

Cu/SiO2 catalysts prepared by a convenient and efficient method using the urea hydrolysis deposition-precipitation （UHDP） technique have been proposed focusing on the effect of copper loading.The texture,structure and composition are systematically characterized by ICP,FTIR,N 2-physisorption,N2O chemisorption,TPR,XRD and XPS.The formation of copper phyllosilicate is observed in Cu/SiO2 catalyst by adopting UHDP method,and the amount of copper phyllosilicate is related to copper loading.It is found the structure properties and catalytic performance is profoundly affected by the amount of copper phyllosilicate.The excellent catalytic activity is attributed to the synergetic effect between Cu0 and Cu ＋.DMO conversion and EG selectivity are determined by the amount of Cu0 and Cu＋,respectively.The proper copper loading （30 wt%） provides with the highest ratio of Cu ＋ /Cu0,giving rise to the highest EG yield of 95% under the reaction conditions of p=2.0 MPa,T=473 K,H2/DMO=80 and LHSV=1.0h-1.

Synthesis of 2-methylpyrazine from cyclocondensation of ethylene diamine and propylene glycol over promoted copper catalyst

The 2-methylpyrazine was synthesized by catalytic reaction of ethylene diamine and propylene glycol at 380 ℃. The alumina supported copper catalysts with promoter were prepared by impregnation method, characterized by ICP-AES, BET and TPR. The results demonstrated that the dehydrogenation was improved by addition of chromium promoter. The selectivity of 2-methylpyrazine reached 84.75%, while the conversions of reactants were also enhanced.

2-AMINOMETHYLPYRIDINE NICKEL(Ⅱ) COMPLEXES—SYNTHESIS,MOLECULAR STRUCTURE AND CATALYSIS OF ETHYLENE POLYMERIZATION

A series of new nickel(Ⅱ)complexes with 2-aminomethylpyridine ligands,(2-PyCH_2NHAr)_2NiBr_2(Ar=2,6- dimethylphenyl 2a;2,6-diisopropylphenyl 2b,2,6-difluorophenyl 2c),have been synthesized and used as catalyst precursors for ethylene polymerization in the presence of methylaluminoxane(MAO).The catalysts containing ortho-alkyl-substituents afford high molecular weight branched polyethylenes as well as a certain amount of oligomers.Enhancing the steric bulk of the alkyl substituent of the catalyst resulted in...

Catalytic Performance and Texture of TEOS Based Cu/SiO_2 Catalysts for Hydrogenation of Dimethyl Oxalate to Ethylene Glycol

Highly active and selective Cu/SiO2 catalysts for hydrogenation of dimethyl oxalate（DMO） to ethylene glycol（EG） were successfully prepared by means of a convenient one-pot synthetic method with tetraethoxysi lane（TEOS） as the source of silica. XRD, H2-TPR, SEM, TEM, XRF and N2 physisorption measurements were performed to characterize the texture and structure of Cu/SiO2 catalysts with different copper loadings. The active components were highly dispersed on SiO2 supports. Furthermore, the coexistence of Cu0 and Cu＋ contributed a lot to the excellent performance of Cu-TEOS catalysts. The DMO conversion reached 100% and the EG selectivity reached 95% at 498 K and 2 MPa with a high liquid hourly space velocity over the 27-Cu-TEOS catalyst with an actual cop per loading of 19.0%（mass fraction）.

Revealing the roles of components in glucose selective hydrogenation into 1,2-propanediol and ethylene glycol over Ni-MnO_x-ZnO catalysts

MnOx-promoted Ni-based catalyst supported by ZnO was developed to selectively hydrogenate glucose into polyols in water at 523 K with a yield of 64.9%. Using glucose, sorbitol, glycerol and LA as the rawmaterials, the roles of nickel, ZnO and MnOx were investigated. The results show that nickel provided a new pathway of glucose to sorbitol and played an important role in the hydrogenation of C3 intermediates to 1,2-propanediol(1,2-PDO). The high yield of 1, 2-PDO was attributed to effective C–C bond cleavage performance of ZnO support promoted by MnOx. ZnO and MnOx contribute to the conversion of glycerol to lactic acid(LA) and LA to 1, 2-PDO, respectively. A concise pathway for hydrogenation of glucose over Ni-based catalyst was proposed.

Reaction of 1,1-Di-p-methoxyphenyl-2,2-dinitroethylene and 1,1-Di-O-methoxyphenyl-2,2-dinitroethylene with 1-Benzyl-1,4-dihydroni-cotinamide:Evidence for Concerted Electron-hydrogen Atom Trans-fer Mechanism

Di-p-methoxyphenyl-2, 2-dinitroethylene reacts with 1-benzyl-1, 4-dihydronico- tinamide (BNAH) in deaerated acetonitrile to give 1, 1-di-p-methoxyphenyl-2, 2-dinitroethane, while 1, 1-di-O-methoxyphenyl-2, 2-dinitroethylene fails to react with BNAH under the same conditions, which provides evidence for a concerted electron-hydrogen atom transfer mechanism.

Catalytic Effect of Cobalt and Iron Complexes Incorporating Bis(2-aldiminoethyl)amine Ligands on Ethylene Oligomerization

Complexes [MCl 2{CH 3N(CH 2CH 2N[CDS1]CR 1R 2) 2}]((3, M=Co, R 1=H, R 2=Ph ; 4, M=Fe, R 1=H, \{R 2=Ph\}; 5, M=Co, R 1=R 2=Ph) were prepared and characterized by IR spectra and elemental analysis. The combination of each of complexes 3-5 with ethylaluminoxane(EAO), respectively, was found to be moderately active for ethylene oligomerization to low carbon olefins. The activity of 113 kg oligomers·mol -1 Co·h -1 for complex 3(100 mol of EAO, 180 ℃ and 1 8 MPa ethylene) was observed with a selectivity of 93% to C 4-10 olefins, of which 96% were linear C4 10 olefins. The catalytic properties of complexes 3-5 were compared with those of analogous P,P coordinated complexes [MCl 2{CH 3N(CH 2CH 2PPh 2) 2}](1, M=Co; 2, \{M=\}Fe).

CONDUCTING BLENDS OF POLY (2-VINYL PYRIDINE) AND POLYETHYLENE OXIDE WITH HIGH MOLECULAR WEIGHT

Ionic, electronic and mixed (ionic-electronic) conductivities of blends of poly(2-vinyl pyridine) (P2VP) and poly(ethylene oxide) (PEO) with high molecular weight after doped with LiClO4, TCNQ or LiClO4 and TCNQ were investigated. Effects of LiClO4 and TCNQ concentrations on the conductivity of PEO/P2VP/LiClO4 or TCNQ blend were studied. The ionic conductivity of PEO/P2VP/LiClO4 blend increases with increasing PEO content. At a Li/ethylene bride molar ratio of 0.10 and a TCNQ/2-vinyl pyridine molar ratio of 0.5, the mixed conductivity of PEO/P2VP/LiClO4/TCNQ is higher than the total of ionic conductivity of PEO/P2VP/LiClO4 and electronic conductivity of PEO/P2VP/TCNQ when the weight ratio of PEO and P2VP is 6/4 or 5/5. Scanning electron microscopy (SEM) on the broken cross-section of the PEO/P2VP/LiClO4 blend and differential scanning calorimetry (DSC) results show that LiClO4 could act as a compatibilizer in the blend.

Pt-modulated Cu/SiO_(2) catalysts for efficient hydrogenation of CO_(2)-derived ethylene carbonate to methanol and ethylene glycol

Copper-based catalysts were widely used in the heterogeneous selective hydrogenation of ethylene carbonate(EC),a key step in the indirect conversion of CO_(2) to methanol.However,a high H_(2)/EC molar ratio in feed is required to achieve favorable activity and the methanol selectivity still needs to be improved.Herein,we fabricated a series of Pt-modulated Cu/SiO_(2) catalysts and investigated their catalytic performance for hydrogenation of EC in a fixed bed reactor.By modulating the Pt amount,the optimal 0.2Pt-Cu/SiO_(2) catalyst exhibited the highest catalytic performance with99%EC conversion,over 98%selectivity to ethylene glycol and 95.8%selectivity to methanol at the H_(2)/EC ratio as low as 60 in feed.In addition,0.2Pt-Cu/SiO_(2) catalyst showed excellent stability for 150 h on stream over different H_(2)/EC ratios of 180-40.It is demonstrated a proper amount of Pt could significantly lower the H_(2)/EC molar ratio,promote the reducibility and dispersion of copper,and also enhance surface density of Cu+species.This could be due to the strong interaction of Cu and Pt induced by formation of alloyed Pt single atoms on the Cu lattice.Meanwhile,a relatively higher amount of Pt would deteriorate the catalytic activity,which could be due to the surface coverage and aggregation of active species.These findings may enlighten some fundamental insights for further design of Cu-based catalysts for the hydrogenation of carbon–oxygen bonds.

CATALYTIC PERFORMANCE OF ETHYLENE HYDROFORMYLATION OVER[H_XRu_3(CO)_9(CCO)]^(2-X)/SiO_2-Al_2O_3,SiO_2 AND MgO(X=0-2)CATALYSTS

The various surface species[H_XRu_3(CO)_9(CCO)]^(2-X)(X=0-2)prepared from impregnation of[PPN]_2[Ru_3(CO)_9(CCO)]on SiO_2-Al_2O_3,SiO_2 and MgO show quite different activities and selectivities for oxygenates and ethane in ethylene hydroformylation.

Metathesis of Butylene-2 and Ethylene to Propylene over 3.0Mo/(Hβ+γ-Al_(2)O_(3))Catalysts with Differentγ-Al_(2)O_(3)Contents

A series of 3.0Mo/(Hβ+γ-Al_(2)O_(3))samples withγ-Al_(2)O_(3)contents in the range of 0_100%(mass fraction)was studied by means of XRD,NH_(3)-TPD,TPR and BET determinations for characterizing their structures.The Hβzeolite structure in the 3.0Mo/Hβsample can be effectively stabilized by adding someγ-Al_(2)O_(3)to Hβzeolite.γ-Al_(2)O_(3)mainly favors the formation of polymolybdate or multilayered Mo oxide,while Hβmainly forms the Al_(2)(MoO_(4))_(3)species,as evaluated by the TPR technique.When used as the catalyst for the metathesis of butylene-2 and ethylene to propylene,there exists a close correlation between the specific surface area and stability of the catalyst.The specific surface area of the catalyst shows the maximum when{(Hβ+}γ-Al_(2)O_(3))contains 30%γ-Al_(2)O_(3),which is in agreement with that of the time needed for the reaction stablization.In the case of maximum surface area,the rate of coke deposition is the minimum.

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.

Quantum Chemical Studies on Structure and Detonation Performance of Bis（2,2-dinitropropyl ethylene）formal

Based on the full optimized molecular geometric structures via B3LYP/6-311＋G（2d,p） method, a new gem-dinitro energetic plasticizer, bis（2,2-dinitropropyl ethylene）formal was investigated in order to search for high-performance energetic material. IR spectrum, heat of formation, and detonation performances were predicted. The bond dissociation energies and bond orders for the weakest bonds were analyzed to investigate the thermal stability of the title compound. The results show that the four N-NO2 BDEs are nearly equal to the values of 164.38 kJ/mol, which shows that the title compound is a stable compound. The detonation velocity and pressure were evaluated by using Kamlet-Jacobs equations based on the theoretical density and condensed HOF. The crystal structure obtained by molec-ular mechanics belongs to P21 space group, with lattice parameters Z=2, a=13.8017 A, b=13.4072 A, c=5.5635 A.

Unraveling the incompatibility mechanism of ethylene carbonate-based electrolytes in sodium metal anodes

Ethylene carbonate(EC)is widely used in lithium-ion batteries due to its optimal overall performance with satisfactory conductivity,relatively stable solid electrolyte interphase(SEI),and wide electrochemical window.EC is also the most widely used electrolyte solvent in sodium ion batteries.However,compared to lithium metal,sodium metal(Na)shows higher activity and reacts violently with EC-based electrolyte(NaPF_(6)as solute),which leads to the failure of sodium metal batteries(SMBs).Herein,we reveal the electrochemical instability mechanism of EC on sodium metal battery,and find that the com-bination of EC and NaPF_(6) is electrically reduced in sodium metal anode during charging,resulting in the reduction of the first coulombic efficiency,and the continuous consumption of electrolyte leads to the cell failure.To address the above issues,an additive modified linear carbonate-based electrolyte is provided as a substitute for EC based electrolytes.Specifically,ethyl methyl carbonate(EMC)and dimethyl carbon-ate(DMC)as solvents and fluoroethylene carbonate(FEC)as SEI-forming additive have been identified as the optimal solvent for NaFP_(6)based electrolyte and used in Na_(4)Fe_(3)(PO_(4))_(2)(P_(2)O_(7))/Na batteries.The batter-ies exhibit excellent capacity retention rate of about 80%over 1000 cycles at a cut-off voltage of 4.3 V.

Ca_(2)MnO_(4)-layered perovskite modified by NaNO_(3)for chemical-looping oxidative dehydrogenation of ethane to ethylene

Chemical-looping oxidative dehydrogenation(CL-ODH)is a process designed for the conversion of alkanes into olefins through cyclic redox reactions,eliminating the need for gaseous O_(2).In this work,we investigated the use of Ca_(2)MnO_(4)-layered perovskites modified with NaNO_(3) dopants,serving as redox catalysts(also known as oxygen carriers),for the CL-ODH of ethane within a temperature range of 700-780℃.Our findings revealed that the incorporation of NaNO_(3) as a modifier significantly-nhanced the selectivity for-thylene generation from Ca_(2)MnO_(4).At 750℃and a gas hourly space velocity of 1300 h^(-1),we achieved an-thane conversion up to 68.17%,accompanied by a corresponding-thylene yield of 57.39%.X-ray photoelectron spectroscopy analysis unveiled that the doping NaNO_(3) onto Ca_(2)MnO_(4) not only played a role in reducing the oxidation state of Mn ions but also increased the lattice oxygen content of the redox catalyst.Furthermore,formation of NaNO_(3) shell on the surface of Ca_(2)MnO_(4) led to a reduction in the concentration of manganese sites and modulated the oxygen-releasing behavior in a step-wise manner.This modulation contributed significantly to the enhanced selectivity for ethylene of the NaNO_(3)-doped Ca_(2)MnO_(4) catalyst.These findings provide compelling evidence for the potential of Ca_(2)MnO_(4)-layered perovskites as promising redox catalysts in the context of CL-ODH reactions.

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.

Three New Zn(Ⅱ)/Cd(Ⅱ) Coordination Polymers Constructed with 2-Mercaptonicotinic Acid and 1,2-Di(4-pyridyl)ethylene: Syntheses and Structure Analysis

Three new Zn（Ⅱ）/Cd（Ⅱ） coordination polymers based on 2-mercaptonicotinic acid （H2mna） with 1,2-di（4-pyridyl）ethylene （dpe） introduced as a bridging ligand have been synthesized via hydrothermal method and structurally characterized by single-crystal X-ray diffraction as well as elemental analysis and IR. As reported in this paper, [Zn2（dpe）0.5（mna）2] （1） can be classified as a two-dimensional layer structure in which the 1D chain composed of Zn（Ⅱ） and mna ligands is bridged by dpe ligands, while the complex named [Zn4（dpe）4（mna）4] （2） is a tetra-nuclear cluster compound. These two compounds are further extended to three-dimensional structures by hydrogen bonds along with C–H…π and π…π interactions. Compound 3 with general formular [Cd2（dpe）0.5（mna）2]·H2O belongs to a three-dimensional porous structure in which the 2D metal layers formed by the coordination of Cd（Ⅱ） and mna ligands are connected with the bridging of dpe ligands.

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.

Synthesis, Crystal Structure and Thermal Properties of N,N′-Bis(5,5-dimethyl-2-phospha-2-thio-1,3-dioxan-2-yl) Ethylene Diamine

The title compound N,N＇-bis（5,5-dimethyl-2-phospha-2-thio-1,3-dioxan-2-yl） ethylene diamine （DPTDEDA, C12H26N2O4P2S2） was synthesized by the reaction of neopentyl glycol, phosphorus thio-chloride and 1,2-ethylenediamine, and characterized by elemental analysis, IR and ^1H NMR spectra. Its crystal structure was determined by single-crystal X-ray diffraction analysis and the thermal property was analyzed by TG analysis. The crystal structure belongs to monoclinic, space group P21/c, with a = 14.557（16）, b = 11.299（12）, c = 12.163（13）A,β = 98.707（19）^o, Dc = 1.305 g/cm^3, Z = 4, γ = 0.71073A,μ（MoKa） = 0.447 mm^-1, Mr = 388.41, V = 1977（4）A3, F（000） = 824, S = 1.107, the final R = 0.0478 and wR = 0.0810 for 1738 observed reflections （I 〉 2σ（I））. X-ray analysis reveals that the crystal structure is centrosymmetrically distributed through 1,2-ethylenediamine to join two distorted six-membered rings. The weak N-H…S interactions are observed and link the molecules into sheets. TG analysis shows that the title compound has good thermal stability and char-forming capability, which are required for an excellent intumescent fire retardant.