Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pell...Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pellets.Addressing the gap in the application of organically-intercalated modified bentonite in the pelletizing field,this study introduces an innovative modification process for bentonite that employs the synergistic effect of mechanical force and dimethyl sulfoxide to enhance the intercalation of organic compounds within bentonite,thus significantly enhancing its binding performance.The colloid value and swell capacity of modified bentonite(98.5 m L/3g and 55.0 m L/g)were much higher than the original bentonite(90.5 m L/3g and 17.5 m L/g).With the decrease of bentonite dosage from1.5wt%to 1.0wt%,the drop number of green pellets from a height of 0.5 m and the compressive strengths of roasted pellets using the modified bentonite(6.0 times and 2916 N per pellet)were significantly higher than those of the original bentonite(4.0 times and 2739 N per pellet).This study provides a comprehensive analysis of the intercalation modification mechanism of bentonite,offering crucial technical insights for the development of high-performance modified bentonite as iron ore pellet binders.展开更多
Molybdenum carbide has shown great potential in various hydrogenation reactions,and serves as a primary active species for synthesis of ethanol from dimethyl oxalate hydrogenation process which is a crucial step in th...Molybdenum carbide has shown great potential in various hydrogenation reactions,and serves as a primary active species for synthesis of ethanol from dimethyl oxalate hydrogenation process which is a crucial step in the efficient utilization of coal resources.In this study,a molybdenum carbide catalyst with a three-dimensional mesh-like hollow structure and lattice defects was carefully designed.The MoO_(3)precursor with abundant oxygen vacancies and defects was prepared by flame spray pyrolysis,and a structural modifier,Cu,was introduced by sputtering.The Cu deposited by sputtering affected the carburization and phase evolution processes.A three-dimensional mesh-like hollow structure composed of defective molybdenum carbide is formed,with theβ-Mo_(2)C exhibiting lattice distortions and defects.This defectiveβ-Mo_(2)C exhibits high reactivity,and facilitates the C=O hydrogenation process,showing a high reactivity of 83.1%yield in the hydrogenation of dimethyl oxalate.This work provides a new approach to the design and application of molybdenum carbide catalysts.展开更多
The efficient catalytic conversion of fossil-based low-carbon small molecules to oxygen-containing chemicals is an attractive research topic in the fields of energy and chemical engineering.The selective oxidation of ...The efficient catalytic conversion of fossil-based low-carbon small molecules to oxygen-containing chemicals is an attractive research topic in the fields of energy and chemical engineering.The selective oxidation of dimethyl ether(DME),which is derived from fossil resources,represents a promising approach to producing high-concentration formaldehyde with low energy consumption.However,there is still a lack of catalysts achieving satisfactory conversion of DME with high selectivity for formaldehyde under mild conditions.In this work,an efficient iron-molybdate(FeMo)catalyst was developed for the selective oxidation of DME to formaldehyde.The DME conversion of 84% was achieved with a superior formaldehyde selectivity(77%)at 300℃,a performance that is superior to all previously reported results.In an approximately 550 h continuous reaction,the catalyst maintained a conversion of 64% and a formaldehyde selectivity of 79%.Combined X-ray diffraction(XRD),Transmission electron microscope(TEM),Ultraviolet-visible spectroscopy(UV-Vis),Hydrogen temperature-programmed reduction(H_(2)-TPR),Fourier transform infrared(FT-IR)analyses,along with density functional theory(DFT)calculations,demonstrated that the excellent FeMo catalyst was composed of active Fe_(2)(MoO_(4))_(3)and MoO_(3)phases,and there was an interaction between them,which contributed to the efficient DME dissociation and smooth hydrogen spillover,leading to a superior DME conversion.With the support of DME/O_(2)pulse experiments,in-situ Raman,in-situ Dimethyl ether infrared spectroscopy(DME-IR)and DFT calculation results,a Mars-van Krevelen(MvK)reaction mechanism was proposed:DME was dissociated on the interface between Fe_(2)(MoO_(4))_(3)and MoO_(3)phases to form active methoxy species firstly,and it dehydrogenated to give hydrogen species;the generated hydrogen species smoothly spilled over from Fe_(2)(MoO_(4))_(3)to MoO_(3)enhanced by the interaction between Fe_(2)(MoO_(4))_(3)and MoO_(3);then the hydrogen species was consumed by MoO_(3),leading to a reduction of MoO_(3),and finally,the reduced MoO_(3)was re-oxidized by O_(2),returning to the initial state.These findings offer valuable insights not only for the development of efficient FeMo catalysts but also for elucidating the reaction mechanism involved in the oxidation of DME to formaldehyde,contributing to the optimized utilization of DME derived from fossil resources.展开更多
In this paper,the research progress of Cu-based catalyst and the activity enhancement strategies in the hydrogenation of dimethyl oxalate(DMO)to ethylene glycol(EG)was reviewed.As a green and economical ethylene glyco...In this paper,the research progress of Cu-based catalyst and the activity enhancement strategies in the hydrogenation of dimethyl oxalate(DMO)to ethylene glycol(EG)was reviewed.As a green and economical ethylene glycol production path,the core of DMO hydrogenation of EG lies in the rational design and optimization of catalysts.This paper first introduces the background of the DMO hydrogenation system EG significance and the important effect of Cu-based catalyst in the reaction,particularly emphasizing the coordination with the Cu^(+)-Cu^(0) species catalytic effect.Then,many factors affecting the activity of Cu-based catalysts were analyzed in detail,including the equilibrium effect between Cu^(0) and Cu+species,the surface dispersion of Cu species,the interaction between metal and support,and the morphology effect of the catalyst.Regarding strategies for improving catalyst performance,this paper summarized effective measures such as optimizing support structure,adding promoters and optimizing preparation methods,and demonstrated the practical application effects of these strategies through representative catalyst examples.In addition,this paper also discusses the complex relationship between the influencing factors and catalyst performance.It points out the key directions for future research,with in-depth exploration of the correlation between catalyst structure and performance,the development of new catalysts,and the application of machine learning and big data technology in the catalyst research and development.In summary,this paper provides comprehensive theoretical guidance and practical reference for the performance optimization of Cu-based catalysts for DMO hydrogenation to EG.展开更多
Sperm cryopreservation is an essential technique for male fertility preservation,especially in men who are undergoing medical treatment.Conventional cryopreservation methods face limitations such as oxidative stress,D...Sperm cryopreservation is an essential technique for male fertility preservation,especially in men who are undergoing medical treatment.Conventional cryopreservation methods face limitations such as oxidative stress,DNA fragmentation,and cytotoxicity associated with traditional cryoprotectants like dimethyl sulfoxide(DMSO).Recent breakthroughs have focused on improving post-thaw sperm viability with novel cryoprotectants and innovative freezing strategies.Prospective approaches include the use of amino acid-based cryoprotectants,deep eutectic solvents,and antioxidants that have been described to prevent oxidative damage and maintain DNA integrity.Vitrification,a high-speed freezing technique that prevents ice crystal formation,has demonstrated superior outcomes compared to conventional slow freezing.Moreover,the Direct Dropping Method,a cryoprotectant-free approach,has been introduced as a contamination-minimizing technique that preserves sperm functionality.Multiomics tools are also utilized to determine biomarkers for protocol optimization.Despite these advancements,cryoprotectant toxicity is a central challenge,emphasizing the necessity for safer agents.Future research must focus on long-term sperm functionality and individualized cryopreservation strategies to maximize reproductive outcomes.The current review highlights the challenges associated with sperm cryopreservation,explores innovative strategies and novel cryoprotectants,underscores the significance of maintaining DNA integrity,and proposes future research directions to improve fertility preservation outcomes.展开更多
The catalytic direct synthesis of dimethyl carbonate(DMC)from CO_(2)and methanol is a crucial approach to utilizing CO_(2)and producing high-value chemicals.However,the high stability of the CO_(2)molecule imposes the...The catalytic direct synthesis of dimethyl carbonate(DMC)from CO_(2)and methanol is a crucial approach to utilizing CO_(2)and producing high-value chemicals.However,the high stability of the CO_(2)molecule imposes thermodynamic limitations on this reaction pathway,along with challenges related to insufficient catalyst activity and stability.Currently,solutions primarily focus on developing efficient catalyst.Herein,La-doped CeO_(2)nanoflower catalysts(La_(x)CeO_(2))were synthesized via hydrothermal method.Characterization reveals that La doping optimizes the pore structure and enriched oxygen vacancies,thereby enhancing catalytic performance.Notably,La_(0.1)CeO_(2)exhibits the largest pore size and highest oxygen vacancy content,achieving a remarkable DMC productivity of 9.42 mmol/g under 140℃,4 MPa of CO_(2),and 3 h of reactio n,surpassing pure CeO_(2)nano flowers.Based on experimental findings and in-situ diffuse infrared Fourier transform analysis,a plausible reaction pathway was proposed.This work underscores the potential of La_(x)CeO_(2)nano flowers as efficient catalysts for sustainable CO_(2)conversion to DMC.展开更多
Periodontitis is a common oral disease characterized by progressive alveolar bone resorption and inflammation of the periodontal tissues.Dimethyl fumarate(DMF)has been used in the treatment of various immune-inflammat...Periodontitis is a common oral disease characterized by progressive alveolar bone resorption and inflammation of the periodontal tissues.Dimethyl fumarate(DMF)has been used in the treatment of various immune-inflammatory diseases due to its excellent anti-inflammatory and antioxidant functions.Here,we investigated for the first time the therapeutic effect of DMF on periodontitis.In vivo studies showed that DMF significantly inhibited periodontal destruction,enhanced mitophagy,and decreased the M1/M2 macrophage ratio.In vitro studies showed that DMF inhibited macrophage polarization toward M1 macrophages and promoted polarization toward M2 macrophages,with improved mitochondrial function,inhibited oxidative stress,and increased mitophagy in RAW 264.7 cells.Furthermore,DMF increased intracellular mitochondrial Tu translation elongation factor(TUFM)levels to maintain mitochondrial homeostasis,promoted mitophagy,and modulated macrophage polarization,whereas TUFM knockdown decreased the protective effect of DMF.Finally,mechanistic studies showed that DMF increased intracellular TUFM levels by protecting TUFM from degradation via the ubiquitin-proteasomal degradation pathway.Our results demonstrate for the first time that DMF protects mitochondrial function and inhibits oxidative stress through TUFM-mediated mitophagy in macrophages,resulting in a shift in the balance of macrophage polarization,thereby attenuating periodontitis.Importantly,this study provides new insights into the prevention of periodontitis.展开更多
The use of fossil fuels significantly contributes to excess CO_(2) emissions.Catalytic hydrogenation of CO_(2) to dimethyl ether(DME)is an effective method for CO_(2) recycling,offering both environmental and economic...The use of fossil fuels significantly contributes to excess CO_(2) emissions.Catalytic hydrogenation of CO_(2) to dimethyl ether(DME)is an effective method for CO_(2) recycling,offering both environmental and economic benefits.Zeolites,known for their efficiency as solid catalysts,are widely utilized in the chemical industries.Bifunctional catalysts based on zeolites have gained attention for their applications in CO_(2) hydrogenation to DME.This review discusses key factors affecting the catalytic performance of zeolites,including topologies,Si/Al ratio,crystal size,and the proximity of metallic species to the zeolite catalysts.Although bifunctional catalytic systems enhance the conversion of CO_(2) to DME,they also lead to high CO selectivity at elevated temperatures,which can limit both DME yield and selectivity.We present recent advancements in the development of bifunctional catalysts for the direct hydrogenation of CO_(2) to DME,providing insights for designing optimized catalysts for tandem reaction systems.展开更多
Ethanol synthesis via dimethyl oxalate hydrogenation has garnered increasing attention in the fields of syngas utilization.Althoughε-Fe_(2)C has been identified as a promising active species for DMO hydrogenation to ...Ethanol synthesis via dimethyl oxalate hydrogenation has garnered increasing attention in the fields of syngas utilization.Althoughε-Fe_(2)C has been identified as a promising active species for DMO hydrogenation to ethanol,its formation is kinetically challenging during carbonization.In this work,a Fe_(4)N phase was first synthesized by pretreating a 30Fe/SiO_(2)catalyst in an ammonia environment,followed by carbonization in a methanol-H_(2) flow to obtain ε-Fe_(2)C as the active phase.Fe_(4)N,rather than Fe-O-Si,facilitates the transformation into iron carbide during the carbonization process.The transformation pathway of iron nitride(Fe_(x)N)is mediated by intermediate iron carbonyl species(Fe-CO),ultimately leading to the formation of iron carbide as the active phase.The resulting catalyst exhibited 40 times higher catalytic activity than the untreated catalyst in DMO hydrogenation.Combined structure properties and DFT calculation revealed that the lower energy barrier ofε-Fe_(2)C for ester hydrogenation underpins/strengthens its superior performance,while the STY of ε-Fe_(2)C is 2.8 times that ofε'-Fe_(2.2)C and 58 times that ofχ-Fe_(5)C_(2).This study provides a novel strategy for designing highly efficient iron carbide catalysts for the esters hydrogenation system.展开更多
The direct conversion of greenhouse gas CO_(2) and low-cost CH3OH into valuable dimethyl carbonate(DMC)offers a promising low-carbon synthetic pathway,but the slow CO_(2) activation kinetics and entropy-decreasing nat...The direct conversion of greenhouse gas CO_(2) and low-cost CH3OH into valuable dimethyl carbonate(DMC)offers a promising low-carbon synthetic pathway,but the slow CO_(2) activation kinetics and entropy-decreasing nature of this reaction significantly restrict DMC yield to below 1%.In this work,2-cyanopyridine(2-CP)was employed as a dehydrating agent to suppress the reverse reaction between DMC and H_(2)O,shifting the thermodynamic equilibrium in favor of DMC production.Under this thermodynamic unconstrained condition,increasing oxygen vacancies,especially in the form of oxygen vacancy clusters,promotes catalytic activity significantly.We achieve a catalytic activity of 211 mmol/(g·h)at 140℃ on H_(2)-treated,oxygen-vacancy-clusters-rich CeO_(2) in the presence of 2-CP,a 1.6-fold increase compared to the activity with air-treated CeO_(2) under identical conditions.The DMC yield reaches 8.54%in a 20mL CH3OH solution with 2-CP,surpassing the calculated DMC yield of about 0.66%from the reaction equilibrium constant under the same conditions and without using the dehydrating agent.This work suggests the importance of using a dehydrating agent and also highlights oxygen vacancy clusters as pivotal active sites to promote DMC synthesis.Achieving sustainable DMC synthesis requires further exploration,encompassing strategies such as methods for regeneration of 2-CP.展开更多
Dimethyl carbonate(DMC)is an important chemical raw material extensively used in organic synthesis,lithium-ion battery electrolytes,etc.The primary method for industrial synthesis of DMC involves transesterification b...Dimethyl carbonate(DMC)is an important chemical raw material extensively used in organic synthesis,lithium-ion battery electrolytes,etc.The primary method for industrial synthesis of DMC involves transesterification between ethylene carbonate and MeOH but faces issues with difficult catalyst separation and low catalytic activity.Based on the synergistic catalytic activity of cation and anion,this study develops poly(ionic liquid)s of[N_(X)PIL][PHO]and[N_(3)PIL][Y]with varying alkaline sites and alkalinity levels.This is accomplished by constructing functional polymer monomers containing free radical polymerization sites and nitrogencontaining alkaline groups,and by polymerizing them with suitable crosslinking monomers in a specific ratio before exchanging the resulting polymers with different anions.Results show that doping with nitrogen-containing alkaline groups leads to enhanced basic functional sites while appropriate anions provide intensified alkalinity levels.The[N_(3)PIL][PHO]obtained exhibits superior catalytic activity in transesterification synthesis of DMC,with a yield of 91.43%and selectivity of 99.96%at a reaction time of 2 h.The study also investigates the impact of poly(ionic liquid)cationic structure and anion types,as well as their interactions,on catalytic performance.The findings reveal that the catalytic activity of poly(ionic liquid)is restricted by the interactions between cation and anion.Based on these findings,a possible reaction mechanism was proposed,providing theoretical support for the high-efficiency production of DMC.展开更多
Accurate detection of dimethyl methylphosphonate(DMMP),a simulant for chemical warfare agents,is vital for both public safety and military defense.However,conventional detection methods suffer from low selectivity,owi...Accurate detection of dimethyl methylphosphonate(DMMP),a simulant for chemical warfare agents,is vital for both public safety and military defense.However,conventional detection methods suffer from low selectivity,owing to interference from structurally similar compounds.In this study,we present a highly sensitive and selective gas sensor utilizing a solid-mounted film bulk acoustic resonator based on carbon nanotubes functionalized with hexafluoroisopropanol(HFiP)to enhance DMMP detection.This approach leverages the strong hydrogen bonding between HFiP and DMMP molecules to significantly improve the sensor’s adsorption capacity and selectivity.To further refine selectivity and at the same time solve the cross-sensitivity problem of sensitive membranes,we introduce a virtual sensor array design,generated by modulating the input power to the resonator,which enables the sensor to operate in multiple response modes across varying vibrational amplitudes.These multimodal responses are subjected to linear discriminant analysis,allowing precise differentiation of DMMP from other volatile organic compounds such as tributyl phosphate and dimethyl phthalate.Our results demonstrate superior performance in terms of both sensitivity and selectivity,offering a robust solution for detecting low-concentration DMMP in complex environments.展开更多
A biodegradable and green organic compound octadecyl dimethyl benzyl amm-onium chloride(ODBAC)was used as an efficient inhibitor for cold rolled steel(CRS)in phosphoric acid(H_(3)PO_(4)).The mechanism of adsorption an...A biodegradable and green organic compound octadecyl dimethyl benzyl amm-onium chloride(ODBAC)was used as an efficient inhibitor for cold rolled steel(CRS)in phosphoric acid(H_(3)PO_(4)).The mechanism of adsorption and film formation of ODBAC on CRS was studied through experimental and theoretical calculations.The weight loss method shows that the inhibition efficiency of ODBAC can reach 92.01%at a concentration of 10 mg·L^(-1).The adsorption of ODBAC on the CRS surface conforms to the Langmuir isotherm model,which is a mixed adsorption mainly based on physical adsorption.The X-ray photoelectron spectroscopy(XPS)and contact angle results confirmed the existence of the ODBAC film and steel surface's hydrophobicity has been significantly enhanced.Electrochemical test results reveal that the film's formation mainly inhibits the cathodic corrosion reaction and effectively increases the charge transfer resistance.Quantum chemical calculations have found that N18 in ODBAC and C24 and C25 on the benzene ring are the key active adsorption sites.Molecular dynamics simulation results indicate that ODBAC can sharply reduce the free fraction volume to 8%and inhibit the diffusion of corrosion particles,meaning that the formed ODBAC film makes it difficult for corrosion particles to penetrate,thus improving the corrosion resistance of CRS in H_(3)PO_(4).展开更多
The hydrogenation of dimethyl oxalate(DMO)to ethanol(Et OH)represents a promising avenue for syngas conversion and plays a pivotal role in advancing sustainable energy economies.Nevertheless,designing catalysts with h...The hydrogenation of dimethyl oxalate(DMO)to ethanol(Et OH)represents a promising avenue for syngas conversion and plays a pivotal role in advancing sustainable energy economies.Nevertheless,designing catalysts with high Et OH yields at low temperatures remains a significant challenge.This study introduces an efficient catalyst featuring a rich SiO_(2)-Ni_(3)Mo_(3)N interface,which achieved a remarkable 97.5%Et OH yield at 210°C and 2 MPa.Impressively,an Et OH yield of 95%was also obtained at 210°C and 1.5 MPa.The research demonstrates that the addition of SiO_(2)fosters the development of a rich SiO_(2)-Ni_(3)Mo_(3)N interface,which enhances the concentration of Lewis acid sites(L-acid)and Brønsted acids sites(B-acid)within the catalyst.This enhancement promotes the adsorption of raw material and intermediate products while increasing H_(2)adsorption,thereby boosting the catalyst's deep hydrogenation capacity.Density functional theory(DFT)simulations indicate that SiO2incorporation modifies the catalyst's metal d-band center through electron transfer,increasing its adsorption capability for raw materials and intermediates and facilitating Et OH production.Consequently,this study achieves high Et OH yields at low temperatures,advances the industrialization process of syngas to Et OH conversion,and offers novel insights into constructing highly active catalytic interfaces for DMO hydrogenation.展开更多
Poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate)(PETG)possesses excellent properties and stability than traditional poly(ethylene terephthalate)(PET).However,the production and application of PETG are ...Poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate)(PETG)possesses excellent properties and stability than traditional poly(ethylene terephthalate)(PET).However,the production and application of PETG are restricted by the expensive monomer(1,4-cyclohexanedimethanol,CHDM).Direct upgrading of waste PET to dimethyl cyclohexane-1,4-dicarboxylate(DMCD)can promote the production of CHDM in large scale.In this work,a bifunctional Ru/UiO-66_(def)-SO_(3)H catalyst was synthesized and utilized in coupled methanolysis(of waste PET to dimethyl terephthalate(DMT))and hydrogenation(of DMT to DMCD)under mild condition.Characterizations revealed that Ru/UiO-66_(def)-SO_(3)H possessed mesopores(dominant channels of 2.72 and 3.44 nm),enlarged surface area(998 m^(2)·g^(–1)),enhanced acidity(580μmol·g^(–1)),and Ru nanoparticles(NPs)dispersed highly(45.1%)compared to those of Ru/UiO-66.These combined advantages could accelerate the methanolysis and hydrogenation reactions simultaneously,promoting the performance of direct upgrading of PET to DMCD in one pot.In particular,the conversion of PET and yield of DMCD over Ru/UiO-66_(def)-SO_(3)H reached 100%and 97.7%at 170℃and 3 MPa H_(2)within 6 h.Moreover,Ru/UiO-66_(def)-SO3H was also capable for the upcycling of waste PET-based products including beverage bottles,textile fiber and packaging film to DMCD.展开更多
Dimethyl ether carbonylation to methyl acetate was comparatively investigated over mor- denite supported copper （Cu/HMOR） catalysts prepared by different methods including evaporation, urea hydrolysis, incipient wet...Dimethyl ether carbonylation to methyl acetate was comparatively investigated over mor- denite supported copper （Cu/HMOR） catalysts prepared by different methods including evaporation, urea hydrolysis, incipient wetness impregnation and ion-exchange. The results showed that Cu/HMOR prepared via iron-exchange method exhibited the highest catalytic activity due to the synergistic effect of active-site metal and acidic molecular sieve support. Conversion of 95.3% and methyl acetate selectivity of 94.9% were achieved under conditions of 210℃, 1.5 MPa, and GSHV of 4883 h-1. The catalysts were characterized by nitrogen absorption, X-ray diffraction, NH3 temperature program desorption, and CO temperature program desorption techniques. It was found that Cu/HMOR prepared by ion-exchange method possessed high surface area, moderate strong acid centers, and CO adsorption centers, which improved catalytic performance for the reaction of CO insertion to dimethyl ether.展开更多
The effect of calcination temperature on the catalytic activity for the dimethyl ether （DME） carbonylation into methyl acetate （MA） was investigated over mordenite supported copper （Cu/HMOR） prepared by ion-exch...The effect of calcination temperature on the catalytic activity for the dimethyl ether （DME） carbonylation into methyl acetate （MA） was investigated over mordenite supported copper （Cu/HMOR） prepared by ion-exchange process. The results showed that the catalytic activity was obviously affected by the calcination temperature. The maximal DME conversion of 97.2% and the MA selectivity of 97.9% were obtained over the Cu/HMOR calcined at 430 ℃ under conditions of 210 ℃, 1.5 MPa, and GSHV of 4883 h^-1. The obtained Cu/HMOR catalysts were characterized by powder X-ray diffraction, N2 absorption, NH3 temperature program desorption, CO temperature program desorption, and Raman techniques. Proper calcination temperature was effective to promote copper ions migration and diffusion, and led the support HMOR to possess more acid activity sites, which exhibited the complete decomposing of copper nitrate, large surface area and optimum micropore structure, more amount of CO adsorption site and proper amount of weak acid centers.展开更多
NaY and ion exchanged NaNH4Y zeolite with NH4NO3 were used as the support to prepare CuY cata‐lysts by a high temperature anhydrous interaction between the support and copper （II） acety‐lacetonate Cu（acac）2. The...NaY and ion exchanged NaNH4Y zeolite with NH4NO3 were used as the support to prepare CuY cata‐lysts by a high temperature anhydrous interaction between the support and copper （II） acety‐lacetonate Cu（acac）2. The catalysts were used for the oxidative carbonylation of methanol to dime‐thyl carbonate （DMC） at atmospheric pressure. The textural and acidic properties of NaNH4Y zeolite and the CuY catalysts were investigated by X‐ray diffraction, scanning electron microscopy, N2 ad‐sorption‐desorption, temperature programmed reduction of H2, X‐ray photoelectron spectroscopy and temperature programmed desorption of NH3. With increasing NH4NO3 concentration, the NH4＋exchange degree increased while the crystallinity of the zeolite remained intact. Crystalline CuO was formed when the NH4＋exchange degree of NaNH4Y was low, and the corresponding CuY catalyst showed low catalytic activity. With increasing of the NH4＋exchange degree of NaNH4Y, the content of surface bound Cu＋active centers increased and the catalytic activity of the corresponding CuY catalyst also increased. The surface bound Cu＋content reached its maximum when the NH4＋ex‐change degree of NaNH4Y reached towards saturation. The CuY exhibited optimal catalytic activity with 267.3 mg/（g·h） space time yield of DMC, 6.9%conversion of methanol, 68.5%selectivity of DMC.展开更多
The total synthesis of 3,7 dimethyl 2 tridecanyl acetate,the active component of the sex pheromone of diprion pini,was investigated in this paper.The two key synthins blocks,2 methyl octan 1 yl lithium and 3,4 ...The total synthesis of 3,7 dimethyl 2 tridecanyl acetate,the active component of the sex pheromone of diprion pini,was investigated in this paper.The two key synthins blocks,2 methyl octan 1 yl lithium and 3,4 dimethyl γ butyrolactone,were obtained from diethyl malonate and 2,3 epoxybutane.2 Methyl octan 1 yl lithium reacted with 3,4 dimethyl γ butyrolactone to yield the ketoalcohol and then followed by Huang Minlong reduction to afford 3,7 dimethyl 2 tridecanol,acylated with acetic anhydide to give 3,7 dimethyl 2 tridecanyl acetate.展开更多
基金financial support by the National Key Research and Development Program of China(No.2023YFC2907801)the Hunan Provincial Natural Science Foundation of China(No.2023JJ40760)the Scientific and Technological Project of Yunnan Precious Metals Laboratory,China(No.YPML-2023050276)。
文摘Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pellets.Addressing the gap in the application of organically-intercalated modified bentonite in the pelletizing field,this study introduces an innovative modification process for bentonite that employs the synergistic effect of mechanical force and dimethyl sulfoxide to enhance the intercalation of organic compounds within bentonite,thus significantly enhancing its binding performance.The colloid value and swell capacity of modified bentonite(98.5 m L/3g and 55.0 m L/g)were much higher than the original bentonite(90.5 m L/3g and 17.5 m L/g).With the decrease of bentonite dosage from1.5wt%to 1.0wt%,the drop number of green pellets from a height of 0.5 m and the compressive strengths of roasted pellets using the modified bentonite(6.0 times and 2916 N per pellet)were significantly higher than those of the original bentonite(4.0 times and 2739 N per pellet).This study provides a comprehensive analysis of the intercalation modification mechanism of bentonite,offering crucial technical insights for the development of high-performance modified bentonite as iron ore pellet binders.
文摘Molybdenum carbide has shown great potential in various hydrogenation reactions,and serves as a primary active species for synthesis of ethanol from dimethyl oxalate hydrogenation process which is a crucial step in the efficient utilization of coal resources.In this study,a molybdenum carbide catalyst with a three-dimensional mesh-like hollow structure and lattice defects was carefully designed.The MoO_(3)precursor with abundant oxygen vacancies and defects was prepared by flame spray pyrolysis,and a structural modifier,Cu,was introduced by sputtering.The Cu deposited by sputtering affected the carburization and phase evolution processes.A three-dimensional mesh-like hollow structure composed of defective molybdenum carbide is formed,with theβ-Mo_(2)C exhibiting lattice distortions and defects.This defectiveβ-Mo_(2)C exhibits high reactivity,and facilitates the C=O hydrogenation process,showing a high reactivity of 83.1%yield in the hydrogenation of dimethyl oxalate.This work provides a new approach to the design and application of molybdenum carbide catalysts.
基金supported by the National Natural Science Foundation of China(U23A2088,22025206)the Dalian Innovation Support Plan for High Level Talents(2022RG13)+2 种基金DICP(Grant:DICP I202453,DICP I202234)the Fundamental Research Funds for the Central Universities(20720220008)support of the Liaoning Key Laboratory of Biomass Conversion for Energy and Material。
文摘The efficient catalytic conversion of fossil-based low-carbon small molecules to oxygen-containing chemicals is an attractive research topic in the fields of energy and chemical engineering.The selective oxidation of dimethyl ether(DME),which is derived from fossil resources,represents a promising approach to producing high-concentration formaldehyde with low energy consumption.However,there is still a lack of catalysts achieving satisfactory conversion of DME with high selectivity for formaldehyde under mild conditions.In this work,an efficient iron-molybdate(FeMo)catalyst was developed for the selective oxidation of DME to formaldehyde.The DME conversion of 84% was achieved with a superior formaldehyde selectivity(77%)at 300℃,a performance that is superior to all previously reported results.In an approximately 550 h continuous reaction,the catalyst maintained a conversion of 64% and a formaldehyde selectivity of 79%.Combined X-ray diffraction(XRD),Transmission electron microscope(TEM),Ultraviolet-visible spectroscopy(UV-Vis),Hydrogen temperature-programmed reduction(H_(2)-TPR),Fourier transform infrared(FT-IR)analyses,along with density functional theory(DFT)calculations,demonstrated that the excellent FeMo catalyst was composed of active Fe_(2)(MoO_(4))_(3)and MoO_(3)phases,and there was an interaction between them,which contributed to the efficient DME dissociation and smooth hydrogen spillover,leading to a superior DME conversion.With the support of DME/O_(2)pulse experiments,in-situ Raman,in-situ Dimethyl ether infrared spectroscopy(DME-IR)and DFT calculation results,a Mars-van Krevelen(MvK)reaction mechanism was proposed:DME was dissociated on the interface between Fe_(2)(MoO_(4))_(3)and MoO_(3)phases to form active methoxy species firstly,and it dehydrogenated to give hydrogen species;the generated hydrogen species smoothly spilled over from Fe_(2)(MoO_(4))_(3)to MoO_(3)enhanced by the interaction between Fe_(2)(MoO_(4))_(3)and MoO_(3);then the hydrogen species was consumed by MoO_(3),leading to a reduction of MoO_(3),and finally,the reduced MoO_(3)was re-oxidized by O_(2),returning to the initial state.These findings offer valuable insights not only for the development of efficient FeMo catalysts but also for elucidating the reaction mechanism involved in the oxidation of DME to formaldehyde,contributing to the optimized utilization of DME derived from fossil resources.
基金supported by Guangxi Science and Technology Major Program(GuikeAA23062018)the Academic Newcomer Award Project of Guangxi University(2025GXUXSXR07)。
文摘In this paper,the research progress of Cu-based catalyst and the activity enhancement strategies in the hydrogenation of dimethyl oxalate(DMO)to ethylene glycol(EG)was reviewed.As a green and economical ethylene glycol production path,the core of DMO hydrogenation of EG lies in the rational design and optimization of catalysts.This paper first introduces the background of the DMO hydrogenation system EG significance and the important effect of Cu-based catalyst in the reaction,particularly emphasizing the coordination with the Cu^(+)-Cu^(0) species catalytic effect.Then,many factors affecting the activity of Cu-based catalysts were analyzed in detail,including the equilibrium effect between Cu^(0) and Cu+species,the surface dispersion of Cu species,the interaction between metal and support,and the morphology effect of the catalyst.Regarding strategies for improving catalyst performance,this paper summarized effective measures such as optimizing support structure,adding promoters and optimizing preparation methods,and demonstrated the practical application effects of these strategies through representative catalyst examples.In addition,this paper also discusses the complex relationship between the influencing factors and catalyst performance.It points out the key directions for future research,with in-depth exploration of the correlation between catalyst structure and performance,the development of new catalysts,and the application of machine learning and big data technology in the catalyst research and development.In summary,this paper provides comprehensive theoretical guidance and practical reference for the performance optimization of Cu-based catalysts for DMO hydrogenation to EG.
文摘Sperm cryopreservation is an essential technique for male fertility preservation,especially in men who are undergoing medical treatment.Conventional cryopreservation methods face limitations such as oxidative stress,DNA fragmentation,and cytotoxicity associated with traditional cryoprotectants like dimethyl sulfoxide(DMSO).Recent breakthroughs have focused on improving post-thaw sperm viability with novel cryoprotectants and innovative freezing strategies.Prospective approaches include the use of amino acid-based cryoprotectants,deep eutectic solvents,and antioxidants that have been described to prevent oxidative damage and maintain DNA integrity.Vitrification,a high-speed freezing technique that prevents ice crystal formation,has demonstrated superior outcomes compared to conventional slow freezing.Moreover,the Direct Dropping Method,a cryoprotectant-free approach,has been introduced as a contamination-minimizing technique that preserves sperm functionality.Multiomics tools are also utilized to determine biomarkers for protocol optimization.Despite these advancements,cryoprotectant toxicity is a central challenge,emphasizing the necessity for safer agents.Future research must focus on long-term sperm functionality and individualized cryopreservation strategies to maximize reproductive outcomes.The current review highlights the challenges associated with sperm cryopreservation,explores innovative strategies and novel cryoprotectants,underscores the significance of maintaining DNA integrity,and proposes future research directions to improve fertility preservation outcomes.
基金supported by Jiangsu Province Science and Technology Plan Special Fund(BZ2022053)National Natural Science Foundation of China(42476239)+1 种基金Natural Science Research Projects of Universities in Jiangsu Province(24KJD530004)the Dean/Opening Project of Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology(2021K008)。
文摘The catalytic direct synthesis of dimethyl carbonate(DMC)from CO_(2)and methanol is a crucial approach to utilizing CO_(2)and producing high-value chemicals.However,the high stability of the CO_(2)molecule imposes thermodynamic limitations on this reaction pathway,along with challenges related to insufficient catalyst activity and stability.Currently,solutions primarily focus on developing efficient catalyst.Herein,La-doped CeO_(2)nanoflower catalysts(La_(x)CeO_(2))were synthesized via hydrothermal method.Characterization reveals that La doping optimizes the pore structure and enriched oxygen vacancies,thereby enhancing catalytic performance.Notably,La_(0.1)CeO_(2)exhibits the largest pore size and highest oxygen vacancy content,achieving a remarkable DMC productivity of 9.42 mmol/g under 140℃,4 MPa of CO_(2),and 3 h of reactio n,surpassing pure CeO_(2)nano flowers.Based on experimental findings and in-situ diffuse infrared Fourier transform analysis,a plausible reaction pathway was proposed.This work underscores the potential of La_(x)CeO_(2)nano flowers as efficient catalysts for sustainable CO_(2)conversion to DMC.
基金Natural Science Foundation of China(grant nos.82270991)Zhejiang Provincial Natural Science Foundation of China/Outstanding Youth Science Foundation(grant no.LR21H140002)+4 种基金Medical Health Science and Technology Major Project of Zhejiang Provincial Health Commission(grant no.WKJ-ZJ-2311)Wenzhou Science and Technology Bureau Public Welfare Social Development(Medical and Health)Science and Technology Project(grant no.ZY2021015)Opening Research Fund from Shanghai Key Laboratory of Stomatology,Shanghai Ninth People’s Hospital,College of Stomatology,Shanghai Jiao Tong University School of Medicine(grant no.2022SKLS-KFKT011)Guangxi Key Laboratory of the Rehabilitation and Reconstruction for Oral and Maxillofacial Research(grant no.GXKLRROM2106)State Key Laboratory of Oral Diseases Open Fund(grant no.SKLOD2024OF08).
文摘Periodontitis is a common oral disease characterized by progressive alveolar bone resorption and inflammation of the periodontal tissues.Dimethyl fumarate(DMF)has been used in the treatment of various immune-inflammatory diseases due to its excellent anti-inflammatory and antioxidant functions.Here,we investigated for the first time the therapeutic effect of DMF on periodontitis.In vivo studies showed that DMF significantly inhibited periodontal destruction,enhanced mitophagy,and decreased the M1/M2 macrophage ratio.In vitro studies showed that DMF inhibited macrophage polarization toward M1 macrophages and promoted polarization toward M2 macrophages,with improved mitochondrial function,inhibited oxidative stress,and increased mitophagy in RAW 264.7 cells.Furthermore,DMF increased intracellular mitochondrial Tu translation elongation factor(TUFM)levels to maintain mitochondrial homeostasis,promoted mitophagy,and modulated macrophage polarization,whereas TUFM knockdown decreased the protective effect of DMF.Finally,mechanistic studies showed that DMF increased intracellular TUFM levels by protecting TUFM from degradation via the ubiquitin-proteasomal degradation pathway.Our results demonstrate for the first time that DMF protects mitochondrial function and inhibits oxidative stress through TUFM-mediated mitophagy in macrophages,resulting in a shift in the balance of macrophage polarization,thereby attenuating periodontitis.Importantly,this study provides new insights into the prevention of periodontitis.
基金the National Key Research and Development Program of China(2021YFA1500401)the National Natural Science Foundation of China(22288101)the‘111 Center’(B17020)for supporting this work.
文摘The use of fossil fuels significantly contributes to excess CO_(2) emissions.Catalytic hydrogenation of CO_(2) to dimethyl ether(DME)is an effective method for CO_(2) recycling,offering both environmental and economic benefits.Zeolites,known for their efficiency as solid catalysts,are widely utilized in the chemical industries.Bifunctional catalysts based on zeolites have gained attention for their applications in CO_(2) hydrogenation to DME.This review discusses key factors affecting the catalytic performance of zeolites,including topologies,Si/Al ratio,crystal size,and the proximity of metallic species to the zeolite catalysts.Although bifunctional catalytic systems enhance the conversion of CO_(2) to DME,they also lead to high CO selectivity at elevated temperatures,which can limit both DME yield and selectivity.We present recent advancements in the development of bifunctional catalysts for the direct hydrogenation of CO_(2) to DME,providing insights for designing optimized catalysts for tandem reaction systems.
基金supported by the National Natural Science Foundation of China(21878227,22278309)。
文摘Ethanol synthesis via dimethyl oxalate hydrogenation has garnered increasing attention in the fields of syngas utilization.Althoughε-Fe_(2)C has been identified as a promising active species for DMO hydrogenation to ethanol,its formation is kinetically challenging during carbonization.In this work,a Fe_(4)N phase was first synthesized by pretreating a 30Fe/SiO_(2)catalyst in an ammonia environment,followed by carbonization in a methanol-H_(2) flow to obtain ε-Fe_(2)C as the active phase.Fe_(4)N,rather than Fe-O-Si,facilitates the transformation into iron carbide during the carbonization process.The transformation pathway of iron nitride(Fe_(x)N)is mediated by intermediate iron carbonyl species(Fe-CO),ultimately leading to the formation of iron carbide as the active phase.The resulting catalyst exhibited 40 times higher catalytic activity than the untreated catalyst in DMO hydrogenation.Combined structure properties and DFT calculation revealed that the lower energy barrier ofε-Fe_(2)C for ester hydrogenation underpins/strengthens its superior performance,while the STY of ε-Fe_(2)C is 2.8 times that ofε'-Fe_(2.2)C and 58 times that ofχ-Fe_(5)C_(2).This study provides a novel strategy for designing highly efficient iron carbide catalysts for the esters hydrogenation system.
基金supported by the National Natural Science Foundation of China(Nos.22272078 and 52371196)the National Key Research and Development Programof the Ministry of Science and Technology of China(No.2020YFA0406102)the“Innovation and Entrepreneurship of Talents plan”of Jiangsu Province.
文摘The direct conversion of greenhouse gas CO_(2) and low-cost CH3OH into valuable dimethyl carbonate(DMC)offers a promising low-carbon synthetic pathway,but the slow CO_(2) activation kinetics and entropy-decreasing nature of this reaction significantly restrict DMC yield to below 1%.In this work,2-cyanopyridine(2-CP)was employed as a dehydrating agent to suppress the reverse reaction between DMC and H_(2)O,shifting the thermodynamic equilibrium in favor of DMC production.Under this thermodynamic unconstrained condition,increasing oxygen vacancies,especially in the form of oxygen vacancy clusters,promotes catalytic activity significantly.We achieve a catalytic activity of 211 mmol/(g·h)at 140℃ on H_(2)-treated,oxygen-vacancy-clusters-rich CeO_(2) in the presence of 2-CP,a 1.6-fold increase compared to the activity with air-treated CeO_(2) under identical conditions.The DMC yield reaches 8.54%in a 20mL CH3OH solution with 2-CP,surpassing the calculated DMC yield of about 0.66%from the reaction equilibrium constant under the same conditions and without using the dehydrating agent.This work suggests the importance of using a dehydrating agent and also highlights oxygen vacancy clusters as pivotal active sites to promote DMC synthesis.Achieving sustainable DMC synthesis requires further exploration,encompassing strategies such as methods for regeneration of 2-CP.
基金supported by the National Natural Science Foundation of China(Grant No.22278077,22408209 and 22108040)National Key Research and Development Program of China(Grant No.2022YFB4101800)+2 种基金Key Program of Qingyuan Innovation Laboratory(Grant No.00221004)Research Program of Qingyuan Innovation Laboratory(Grant No.00523006)Natural Science Foundation of Fujian Province(Grant No.2022J02019,2024J011550).
文摘Dimethyl carbonate(DMC)is an important chemical raw material extensively used in organic synthesis,lithium-ion battery electrolytes,etc.The primary method for industrial synthesis of DMC involves transesterification between ethylene carbonate and MeOH but faces issues with difficult catalyst separation and low catalytic activity.Based on the synergistic catalytic activity of cation and anion,this study develops poly(ionic liquid)s of[N_(X)PIL][PHO]and[N_(3)PIL][Y]with varying alkaline sites and alkalinity levels.This is accomplished by constructing functional polymer monomers containing free radical polymerization sites and nitrogencontaining alkaline groups,and by polymerizing them with suitable crosslinking monomers in a specific ratio before exchanging the resulting polymers with different anions.Results show that doping with nitrogen-containing alkaline groups leads to enhanced basic functional sites while appropriate anions provide intensified alkalinity levels.The[N_(3)PIL][PHO]obtained exhibits superior catalytic activity in transesterification synthesis of DMC,with a yield of 91.43%and selectivity of 99.96%at a reaction time of 2 h.The study also investigates the impact of poly(ionic liquid)cationic structure and anion types,as well as their interactions,on catalytic performance.The findings reveal that the catalytic activity of poly(ionic liquid)is restricted by the interactions between cation and anion.Based on these findings,a possible reaction mechanism was proposed,providing theoretical support for the high-efficiency production of DMC.
基金supported by the State Key Laboratory of Pathogens and Biosecurity(Grant No.SKLPBS2240).
文摘Accurate detection of dimethyl methylphosphonate(DMMP),a simulant for chemical warfare agents,is vital for both public safety and military defense.However,conventional detection methods suffer from low selectivity,owing to interference from structurally similar compounds.In this study,we present a highly sensitive and selective gas sensor utilizing a solid-mounted film bulk acoustic resonator based on carbon nanotubes functionalized with hexafluoroisopropanol(HFiP)to enhance DMMP detection.This approach leverages the strong hydrogen bonding between HFiP and DMMP molecules to significantly improve the sensor’s adsorption capacity and selectivity.To further refine selectivity and at the same time solve the cross-sensitivity problem of sensitive membranes,we introduce a virtual sensor array design,generated by modulating the input power to the resonator,which enables the sensor to operate in multiple response modes across varying vibrational amplitudes.These multimodal responses are subjected to linear discriminant analysis,allowing precise differentiation of DMMP from other volatile organic compounds such as tributyl phosphate and dimethyl phthalate.Our results demonstrate superior performance in terms of both sensitivity and selectivity,offering a robust solution for detecting low-concentration DMMP in complex environments.
基金support from National Natural Science Foundation of China(52161016)Joint Key Project of Agricultural Fundamental Research in Yunnan Province(202101BD070001-017)+2 种基金Yunnan Provincial Academician Workstation(202305AF150009)Special Project of“Top Young Talents”of Yunnan Ten Thousand Talents Plan(51900109)Special Project of“Leading Talents of Industrial Technology”of Yunnan Ten Thousand Talents Plan(80201408)are acknowledged.
文摘A biodegradable and green organic compound octadecyl dimethyl benzyl amm-onium chloride(ODBAC)was used as an efficient inhibitor for cold rolled steel(CRS)in phosphoric acid(H_(3)PO_(4)).The mechanism of adsorption and film formation of ODBAC on CRS was studied through experimental and theoretical calculations.The weight loss method shows that the inhibition efficiency of ODBAC can reach 92.01%at a concentration of 10 mg·L^(-1).The adsorption of ODBAC on the CRS surface conforms to the Langmuir isotherm model,which is a mixed adsorption mainly based on physical adsorption.The X-ray photoelectron spectroscopy(XPS)and contact angle results confirmed the existence of the ODBAC film and steel surface's hydrophobicity has been significantly enhanced.Electrochemical test results reveal that the film's formation mainly inhibits the cathodic corrosion reaction and effectively increases the charge transfer resistance.Quantum chemical calculations have found that N18 in ODBAC and C24 and C25 on the benzene ring are the key active adsorption sites.Molecular dynamics simulation results indicate that ODBAC can sharply reduce the free fraction volume to 8%and inhibit the diffusion of corrosion particles,meaning that the formed ODBAC film makes it difficult for corrosion particles to penetrate,thus improving the corrosion resistance of CRS in H_(3)PO_(4).
基金the financial support from the National Natural Science Foundation of China(No.21962015)the Bingtuan Graduate Innovation Project 2024(No.BTYJXM-2024-K12)。
文摘The hydrogenation of dimethyl oxalate(DMO)to ethanol(Et OH)represents a promising avenue for syngas conversion and plays a pivotal role in advancing sustainable energy economies.Nevertheless,designing catalysts with high Et OH yields at low temperatures remains a significant challenge.This study introduces an efficient catalyst featuring a rich SiO_(2)-Ni_(3)Mo_(3)N interface,which achieved a remarkable 97.5%Et OH yield at 210°C and 2 MPa.Impressively,an Et OH yield of 95%was also obtained at 210°C and 1.5 MPa.The research demonstrates that the addition of SiO_(2)fosters the development of a rich SiO_(2)-Ni_(3)Mo_(3)N interface,which enhances the concentration of Lewis acid sites(L-acid)and Brønsted acids sites(B-acid)within the catalyst.This enhancement promotes the adsorption of raw material and intermediate products while increasing H_(2)adsorption,thereby boosting the catalyst's deep hydrogenation capacity.Density functional theory(DFT)simulations indicate that SiO2incorporation modifies the catalyst's metal d-band center through electron transfer,increasing its adsorption capability for raw materials and intermediates and facilitating Et OH production.Consequently,this study achieves high Et OH yields at low temperatures,advances the industrialization process of syngas to Et OH conversion,and offers novel insights into constructing highly active catalytic interfaces for DMO hydrogenation.
文摘Poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate)(PETG)possesses excellent properties and stability than traditional poly(ethylene terephthalate)(PET).However,the production and application of PETG are restricted by the expensive monomer(1,4-cyclohexanedimethanol,CHDM).Direct upgrading of waste PET to dimethyl cyclohexane-1,4-dicarboxylate(DMCD)can promote the production of CHDM in large scale.In this work,a bifunctional Ru/UiO-66_(def)-SO_(3)H catalyst was synthesized and utilized in coupled methanolysis(of waste PET to dimethyl terephthalate(DMT))and hydrogenation(of DMT to DMCD)under mild condition.Characterizations revealed that Ru/UiO-66_(def)-SO_(3)H possessed mesopores(dominant channels of 2.72 and 3.44 nm),enlarged surface area(998 m^(2)·g^(–1)),enhanced acidity(580μmol·g^(–1)),and Ru nanoparticles(NPs)dispersed highly(45.1%)compared to those of Ru/UiO-66.These combined advantages could accelerate the methanolysis and hydrogenation reactions simultaneously,promoting the performance of direct upgrading of PET to DMCD in one pot.In particular,the conversion of PET and yield of DMCD over Ru/UiO-66_(def)-SO_(3)H reached 100%and 97.7%at 170℃and 3 MPa H_(2)within 6 h.Moreover,Ru/UiO-66_(def)-SO3H was also capable for the upcycling of waste PET-based products including beverage bottles,textile fiber and packaging film to DMCD.
文摘Dimethyl ether carbonylation to methyl acetate was comparatively investigated over mor- denite supported copper （Cu/HMOR） catalysts prepared by different methods including evaporation, urea hydrolysis, incipient wetness impregnation and ion-exchange. The results showed that Cu/HMOR prepared via iron-exchange method exhibited the highest catalytic activity due to the synergistic effect of active-site metal and acidic molecular sieve support. Conversion of 95.3% and methyl acetate selectivity of 94.9% were achieved under conditions of 210℃, 1.5 MPa, and GSHV of 4883 h-1. The catalysts were characterized by nitrogen absorption, X-ray diffraction, NH3 temperature program desorption, and CO temperature program desorption techniques. It was found that Cu/HMOR prepared by ion-exchange method possessed high surface area, moderate strong acid centers, and CO adsorption centers, which improved catalytic performance for the reaction of CO insertion to dimethyl ether.
基金This work was supported by the National Natural Science Foundation of China （No.51006110 and No.51276183） and the National Natural Research Foundation of China/Japan Science and Technology Agency （No.51161140331）.
文摘The effect of calcination temperature on the catalytic activity for the dimethyl ether （DME） carbonylation into methyl acetate （MA） was investigated over mordenite supported copper （Cu/HMOR） prepared by ion-exchange process. The results showed that the catalytic activity was obviously affected by the calcination temperature. The maximal DME conversion of 97.2% and the MA selectivity of 97.9% were obtained over the Cu/HMOR calcined at 430 ℃ under conditions of 210 ℃, 1.5 MPa, and GSHV of 4883 h^-1. The obtained Cu/HMOR catalysts were characterized by powder X-ray diffraction, N2 absorption, NH3 temperature program desorption, CO temperature program desorption, and Raman techniques. Proper calcination temperature was effective to promote copper ions migration and diffusion, and led the support HMOR to possess more acid activity sites, which exhibited the complete decomposing of copper nitrate, large surface area and optimum micropore structure, more amount of CO adsorption site and proper amount of weak acid centers.
基金supported by the National Natural Science Foundation of China (21276169)~~
文摘NaY and ion exchanged NaNH4Y zeolite with NH4NO3 were used as the support to prepare CuY cata‐lysts by a high temperature anhydrous interaction between the support and copper （II） acety‐lacetonate Cu（acac）2. The catalysts were used for the oxidative carbonylation of methanol to dime‐thyl carbonate （DMC） at atmospheric pressure. The textural and acidic properties of NaNH4Y zeolite and the CuY catalysts were investigated by X‐ray diffraction, scanning electron microscopy, N2 ad‐sorption‐desorption, temperature programmed reduction of H2, X‐ray photoelectron spectroscopy and temperature programmed desorption of NH3. With increasing NH4NO3 concentration, the NH4＋exchange degree increased while the crystallinity of the zeolite remained intact. Crystalline CuO was formed when the NH4＋exchange degree of NaNH4Y was low, and the corresponding CuY catalyst showed low catalytic activity. With increasing of the NH4＋exchange degree of NaNH4Y, the content of surface bound Cu＋active centers increased and the catalytic activity of the corresponding CuY catalyst also increased. The surface bound Cu＋content reached its maximum when the NH4＋ex‐change degree of NaNH4Y reached towards saturation. The CuY exhibited optimal catalytic activity with 267.3 mg/（g·h） space time yield of DMC, 6.9%conversion of methanol, 68.5%selectivity of DMC.
基金Supported by Foundation for University Key Teacher by the Min-istry of Education
文摘The total synthesis of 3,7 dimethyl 2 tridecanyl acetate,the active component of the sex pheromone of diprion pini,was investigated in this paper.The two key synthins blocks,2 methyl octan 1 yl lithium and 3,4 dimethyl γ butyrolactone,were obtained from diethyl malonate and 2,3 epoxybutane.2 Methyl octan 1 yl lithium reacted with 3,4 dimethyl γ butyrolactone to yield the ketoalcohol and then followed by Huang Minlong reduction to afford 3,7 dimethyl 2 tridecanol,acylated with acetic anhydide to give 3,7 dimethyl 2 tridecanyl acetate.
