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 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
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
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
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
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
NiSAPO-34 and NiSAPO-34/HZSM-5 were prepared and evaluated for the performance of dimethyl ether （DME） conversion to light olefins （DTO）. The processes of two-stage light olefin production, DME synthesis and the f...NiSAPO-34 and NiSAPO-34/HZSM-5 were prepared and evaluated for the performance of dimethyl ether （DME） conversion to light olefins （DTO）. The processes of two-stage light olefin production, DME synthesis and the following DTO, were also investigated using biosyngas as feed gas over Cu/Zn/A1/HZSM-5 and the optimized 2%NiSAPO-34/HZSM- 5. The results indicated that adding 2%Ni to SAPO-34 did not change its topology structure, but resulted in the forming of the moderately strong acidity with decreasing acid amounts, which slightly enhanced DME conversion activity and C2=-C3= selectiw ity. Mechanically mixing 2%NiSAPO-34 with HZSM-5 at the weight ratio of 3.0 further prolonged DME conversion activity to be more than 3 h, which was due to the stable acid sites from HZSM-5. The highest selectivity to light olefins of 90.8% was achieved at 2 h time on stream. The application of the optimized 2%NiSAPO-34/HZSM-5 in the second-stage reactor for DTO reaction showed that the catalytic activity was steady for more than 5 h and light olefin yield was as high as 84.6 g/m3syngas when the biosyngas （H2/CO/CO2/N2/CH4=41.5/26.9/14.2/14.6/2.89, vol%） with low H/C ratio of 1.0 was used as feed gas.展开更多
A novel direct method for preparation of dimethyl carbonate and poly（ethylene terephthalate） from ethylene carbonate and dimethyl terephthalate has been demonstrated in the presence of metal acetate catalysts, lithi...A novel direct method for preparation of dimethyl carbonate and poly（ethylene terephthalate） from ethylene carbonate and dimethyl terephthalate has been demonstrated in the presence of metal acetate catalysts, lithium acetate dihydrate showed highest catalytic activity with 47.9% yield of dimethyl carbonate. This method was a green chemical process.展开更多
The global climate is intimately connected to changes in the polar oceans. The variability of sea ice coverage affects deep-water formations and large-scale thermohaline circulation patterns. The polar radiative budge...The global climate is intimately connected to changes in the polar oceans. The variability of sea ice coverage affects deep-water formations and large-scale thermohaline circulation patterns. The polar radiative budget is sensitive to sea-ice loss and consequent surface albedo changes. Aerosols and polar cloud microphysics are crucial players in the radioactive energy balance of the Arctic Ocean. The main biogenic source of sulfate aerosols to the atmosphere above remote seas is dimethylsulfide (DMS). Recent research suggests the flux of DMS to the Arctic atmosphere may change markedly under global warming. This paper describes climate data and DMS production (based on the five years from 1998 to 2002) in the region of the Barents Sea (30–35°E and 70–80°N). A DMS model is introduced together with an updated calibration method. A genetic algorithm is used to calibrate the chlorophyll-a (CHL) measurements (based on satellite SeaWiFS data) and DMS content (determined from cruise data collected in the Arctic). Significant interannual variation of the CHL amount leads to significant interannual variability in the observed and modeled production of DMS in the study region. Strong DMS production in 1998 could have been caused by a large amount of ice algae being released in the southern region. Forcings from a general circulation model (CSIRO Mk3) were applied to the calibrated DMS model to predict the zonal mean sea-to-air flux of DMS for contemporary and enhanced greenhouse conditions at 70–80°N. It was found that significantly decreasing ice coverage, increasing sea surface temperature and decreasing mixed-layer depth could lead to annual DMS flux increases of more than 100% by the time of equivalent CO2 tripling (the year 2080). This significant perturbation in the aerosol climate could have a large impact on the regional Arctic heat budget and consequences for global warming.展开更多
Dimethyl carbonate （DMC） and poly（ethylene terephthalate） was simultaneously synthesized by the transesterification of ethylene carbonate （EC） with dimethyl terephthalate （DMT） in this paper. This reaction is ...Dimethyl carbonate （DMC） and poly（ethylene terephthalate） was simultaneously synthesized by the transesterification of ethylene carbonate （EC） with dimethyl terephthalate （DMT） in this paper. This reaction is an excellent green chemical process without poisonous substance. Various alkali metals were used as the catalysts. The results showed alkali metals had catalytic activity in a certain extent. The effect of reaction condition was also studied. When the reaction was carded out under the following conditions： the reaction temperature 250℃, molar ratio of EC to DMT 3 ： 1, reaction time 3h, and catalyst amount 0.004 （molar ratio to DMT）, the yield of DMC was 68.9%.展开更多
The reaction between ethylene carbonate and dimethyl terephthalate was carried out for the simultaneous synthesis of dimethyl carbonate and poly（ethylene terephthalate）, This reaction is an excellent chemical proces...The reaction between ethylene carbonate and dimethyl terephthalate was carried out for the simultaneous synthesis of dimethyl carbonate and poly（ethylene terephthalate）, This reaction is an excellent chemical process that is environmentally friendly and produces no poisonous substance. The metal acetate catalysts used for this reaction are discussed in detail. Lithium acetate dihydrate was found to be a novel and efficient catalyst for this reaction. Compared with other metal acetates, lithium acetate dihydrate can attain a maximum catalytic activity at a lower concentration. When the reaction was carried out under the following conditions： the reaction temperature from 230 to 250 ℃, molar ratio of ethylene carbonate（EC） to dimethyl terephthalate（DMT） 3： 1, reaction time 3 h, and a catalyst amount of 0. 4% （molar fraction to DMT）, the yield of dimethyl carbonate（DMC） was 79. 1%.展开更多
The activities of dimethyl carbonate and dimethyl sulfate as a methylation reagent were studied by density- functional theory （DFT）. B3LYP/6-31G（d, p） methods were used to optimize the structures of dirnethyl carb...The activities of dimethyl carbonate and dimethyl sulfate as a methylation reagent were studied by density- functional theory （DFT）. B3LYP/6-31G（d, p） methods were used to optimize the structures of dirnethyl carbonate and dimethyl sulfate and calculate theirs charge densities. Dimethyl sulfate is easier than dimethyl carbonate to react with a nucleophUic reagent. In dimethyl sulfate, the alkoxy carbons are the only reactive atomic nucleus because of steric hindrance. A nucleophilic reagent is more likely to react with carbonyl carbons than alkoxy carbons of dimethyl carbonate; in the presence of a Lewis acid, the phenyl nucleophilic reagent reacts with the Lewis acid first. Lewis acid increases the negative charge density of a nucleophUic reagent in polar solvent, and also incurs an accretion of steric hindrance. Polar solvent avails to ionize dimethyl carbonate and thus enables the reaction of methylation. The frequencies of transition state calculated by Gaussion 03 confirm the inferred reaction mechanism. The harvest rates of 4-methoxyphenol in the experiments of methylation reactions of hydroquinone with respectively dimethyl carbonate and dimethyl sulfate support the foregoing theortical conclusions.展开更多
An efficient synthesis of 2,6-pyridine dimethyl formate happened under the microwave irradiation is proposed. It is noteworthy that some factors influence the product yield such as time, temperature, ratio of reactant...An efficient synthesis of 2,6-pyridine dimethyl formate happened under the microwave irradiation is proposed. It is noteworthy that some factors influence the product yield such as time, temperature, ratio of reactants, and acidity which were discussed. The optimized quantity of 2,6-pyridine dimethyl acid is 10 mmol and methanol is 25 mmol. The yield is up to 95%-96% when using 2 mL 30% sulfuric acid. All products have been characterized by IR and 1H NMR.展开更多
An all-atom dimethyl sulfoxide （DMSO） and water model have been used for molecular dynamics simulation. The NMR and IR spectra are also performed to study the structures and interactions in the DMSO-water system. An...An all-atom dimethyl sulfoxide （DMSO） and water model have been used for molecular dynamics simulation. The NMR and IR spectra are also performed to study the structures and interactions in the DMSO-water system. And there are traditional strong hydrogen bonds and weak C-H- ~ ~ O contacts existing in the mixtures according to the analysis of the radial distribution functions. The insight structures in the DMSO-water mixtures can be classified into different regions by the analysis of the hydrogen-bonding network. Interestingly, the molar fraction of DMSO 0.35 is found to be a special concentration by the network. It is the transitional region which is from the water rich region to the DMSO rich region. The stable aggregates of （DMSO）m＇S=O…… HW-OW-（H20）n might play a key role in this region. Moreover, the simulation is compared with the chemical shifts in NMR and wavenumbers in IR with concentration dependence. And the statistical results of the average number hydrogen bonds in the MD simulations are in agreement with the experiment data in NMR and IR spectra.展开更多
Vanadium pentoxide（V2O5）/molybdenum trioxide（MoO 3） composites with different molar ratios of vanadium（V） to molybdenum（Mo） were synthesized via a simple electrospinning technique. The photocatalytic activity ...Vanadium pentoxide（V2O5）/molybdenum trioxide（MoO 3） composites with different molar ratios of vanadium（V） to molybdenum（Mo） were synthesized via a simple electrospinning technique. The photocatalytic activity of the composites were evaluated by their ability to photodegrade methylene blue and dimethyl phthalate（DMP） under visible-light irradiation. Compared with pure V2O5 and MoO 3,the V2O5/MoO 3 composites showed enhanced visible-light photocatalytic activity because of a V 3d impurity energy level and the formation of heterostructures at the interface between V2O5 and MoO 3. The optimal molar ratio of V to Mo in the V2O5/MoO 3 composites was found to be around 1/2. Furthermore,high-performance liquid chromatographic monitoring revealed that phthalic acid was the main intermediate in the photocatalytic degradation process of DMP.展开更多
Dimethyl-1-(1, 2, 4-triazol) -2- butanone was treated with aqueous formaldehyde to give an additional product, and subsequent elimination by acetic anhydride yielded 4, 4-dimethyl-2-(1, 2, 4-triazol)-1-penten-3-one. ...Dimethyl-1-(1, 2, 4-triazol) -2- butanone was treated with aqueous formaldehyde to give an additional product, and subsequent elimination by acetic anhydride yielded 4, 4-dimethyl-2-(1, 2, 4-triazol)-1-penten-3-one. Further addition with substituted amines provided a series of (1, 2, 4-triazol)-4, 4-dimethyl-3-pentanone, which were then reduced by KBH4 to obtain a series of (1, 2, 4-triazol)-4, 4-dimethyl-3-pentanol. Their structures were confirmed by 1HNMR and elemental analysis. The results of bioassay showed that the title products possess good fungicidal activities.展开更多
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.
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 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ACKNOWLEDGM ENTS This work was supported by the National Natural Science Foundation of China （No.51006110, No.51276183, and No.51036006）, the National Natural Research Foundation of China/Japan Science and Technology Agency （No.51161140331）, and National Key Basic Research Program 973 Project Founded by MOST of China （No.2013CB228105）.
文摘NiSAPO-34 and NiSAPO-34/HZSM-5 were prepared and evaluated for the performance of dimethyl ether （DME） conversion to light olefins （DTO）. The processes of two-stage light olefin production, DME synthesis and the following DTO, were also investigated using biosyngas as feed gas over Cu/Zn/A1/HZSM-5 and the optimized 2%NiSAPO-34/HZSM- 5. The results indicated that adding 2%Ni to SAPO-34 did not change its topology structure, but resulted in the forming of the moderately strong acidity with decreasing acid amounts, which slightly enhanced DME conversion activity and C2=-C3= selectiw ity. Mechanically mixing 2%NiSAPO-34 with HZSM-5 at the weight ratio of 3.0 further prolonged DME conversion activity to be more than 3 h, which was due to the stable acid sites from HZSM-5. The highest selectivity to light olefins of 90.8% was achieved at 2 h time on stream. The application of the optimized 2%NiSAPO-34/HZSM-5 in the second-stage reactor for DTO reaction showed that the catalytic activity was steady for more than 5 h and light olefin yield was as high as 84.6 g/m3syngas when the biosyngas （H2/CO/CO2/N2/CH4=41.5/26.9/14.2/14.6/2.89, vol%） with low H/C ratio of 1.0 was used as feed gas.
文摘A novel direct method for preparation of dimethyl carbonate and poly（ethylene terephthalate） from ethylene carbonate and dimethyl terephthalate has been demonstrated in the presence of metal acetate catalysts, lithium acetate dihydrate showed highest catalytic activity with 47.9% yield of dimethyl carbonate. This method was a green chemical process.
基金Supported by the Nantong University Research Funding (No. 09R02)
文摘The global climate is intimately connected to changes in the polar oceans. The variability of sea ice coverage affects deep-water formations and large-scale thermohaline circulation patterns. The polar radiative budget is sensitive to sea-ice loss and consequent surface albedo changes. Aerosols and polar cloud microphysics are crucial players in the radioactive energy balance of the Arctic Ocean. The main biogenic source of sulfate aerosols to the atmosphere above remote seas is dimethylsulfide (DMS). Recent research suggests the flux of DMS to the Arctic atmosphere may change markedly under global warming. This paper describes climate data and DMS production (based on the five years from 1998 to 2002) in the region of the Barents Sea (30–35°E and 70–80°N). A DMS model is introduced together with an updated calibration method. A genetic algorithm is used to calibrate the chlorophyll-a (CHL) measurements (based on satellite SeaWiFS data) and DMS content (determined from cruise data collected in the Arctic). Significant interannual variation of the CHL amount leads to significant interannual variability in the observed and modeled production of DMS in the study region. Strong DMS production in 1998 could have been caused by a large amount of ice algae being released in the southern region. Forcings from a general circulation model (CSIRO Mk3) were applied to the calibrated DMS model to predict the zonal mean sea-to-air flux of DMS for contemporary and enhanced greenhouse conditions at 70–80°N. It was found that significantly decreasing ice coverage, increasing sea surface temperature and decreasing mixed-layer depth could lead to annual DMS flux increases of more than 100% by the time of equivalent CO2 tripling (the year 2080). This significant perturbation in the aerosol climate could have a large impact on the regional Arctic heat budget and consequences for global warming.
基金the National High Technology Research and Development Program of China(No.2003AA321010).
文摘Dimethyl carbonate （DMC） and poly（ethylene terephthalate） was simultaneously synthesized by the transesterification of ethylene carbonate （EC） with dimethyl terephthalate （DMT） in this paper. This reaction is an excellent green chemical process without poisonous substance. Various alkali metals were used as the catalysts. The results showed alkali metals had catalytic activity in a certain extent. The effect of reaction condition was also studied. When the reaction was carded out under the following conditions： the reaction temperature 250℃, molar ratio of EC to DMT 3 ： 1, reaction time 3h, and catalyst amount 0.004 （molar ratio to DMT）, the yield of DMC was 68.9%.
基金the National High Technology Research and Development Program of China(No 2003AA321010)
文摘The reaction between ethylene carbonate and dimethyl terephthalate was carried out for the simultaneous synthesis of dimethyl carbonate and poly（ethylene terephthalate）, This reaction is an excellent chemical process that is environmentally friendly and produces no poisonous substance. The metal acetate catalysts used for this reaction are discussed in detail. Lithium acetate dihydrate was found to be a novel and efficient catalyst for this reaction. Compared with other metal acetates, lithium acetate dihydrate can attain a maximum catalytic activity at a lower concentration. When the reaction was carried out under the following conditions： the reaction temperature from 230 to 250 ℃, molar ratio of ethylene carbonate（EC） to dimethyl terephthalate（DMT） 3： 1, reaction time 3 h, and a catalyst amount of 0. 4% （molar fraction to DMT）, the yield of dimethyl carbonate（DMC） was 79. 1%.
文摘The activities of dimethyl carbonate and dimethyl sulfate as a methylation reagent were studied by density- functional theory （DFT）. B3LYP/6-31G（d, p） methods were used to optimize the structures of dirnethyl carbonate and dimethyl sulfate and calculate theirs charge densities. Dimethyl sulfate is easier than dimethyl carbonate to react with a nucleophUic reagent. In dimethyl sulfate, the alkoxy carbons are the only reactive atomic nucleus because of steric hindrance. A nucleophilic reagent is more likely to react with carbonyl carbons than alkoxy carbons of dimethyl carbonate; in the presence of a Lewis acid, the phenyl nucleophilic reagent reacts with the Lewis acid first. Lewis acid increases the negative charge density of a nucleophUic reagent in polar solvent, and also incurs an accretion of steric hindrance. Polar solvent avails to ionize dimethyl carbonate and thus enables the reaction of methylation. The frequencies of transition state calculated by Gaussion 03 confirm the inferred reaction mechanism. The harvest rates of 4-methoxyphenol in the experiments of methylation reactions of hydroquinone with respectively dimethyl carbonate and dimethyl sulfate support the foregoing theortical conclusions.
文摘An efficient synthesis of 2,6-pyridine dimethyl formate happened under the microwave irradiation is proposed. It is noteworthy that some factors influence the product yield such as time, temperature, ratio of reactants, and acidity which were discussed. The optimized quantity of 2,6-pyridine dimethyl acid is 10 mmol and methanol is 25 mmol. The yield is up to 95%-96% when using 2 mL 30% sulfuric acid. All products have been characterized by IR and 1H NMR.
文摘An all-atom dimethyl sulfoxide （DMSO） and water model have been used for molecular dynamics simulation. The NMR and IR spectra are also performed to study the structures and interactions in the DMSO-water system. And there are traditional strong hydrogen bonds and weak C-H- ~ ~ O contacts existing in the mixtures according to the analysis of the radial distribution functions. The insight structures in the DMSO-water mixtures can be classified into different regions by the analysis of the hydrogen-bonding network. Interestingly, the molar fraction of DMSO 0.35 is found to be a special concentration by the network. It is the transitional region which is from the water rich region to the DMSO rich region. The stable aggregates of （DMSO）m＇S=O…… HW-OW-（H20）n might play a key role in this region. Moreover, the simulation is compared with the chemical shifts in NMR and wavenumbers in IR with concentration dependence. And the statistical results of the average number hydrogen bonds in the MD simulations are in agreement with the experiment data in NMR and IR spectra.
基金supported by the National Natural Science Foundation of China(2137312021471022)+5 种基金the Development of Science and Technology Plan of Jilin ProvinceChina(2010154920130102001JC)Program for Changjiang Scholars and Innovative Research Team in University(PCSIRT13022)of Chinathe Program of Jilin Provincial Education Department(20131302013146)~~
文摘Vanadium pentoxide（V2O5）/molybdenum trioxide（MoO 3） composites with different molar ratios of vanadium（V） to molybdenum（Mo） were synthesized via a simple electrospinning technique. The photocatalytic activity of the composites were evaluated by their ability to photodegrade methylene blue and dimethyl phthalate（DMP） under visible-light irradiation. Compared with pure V2O5 and MoO 3,the V2O5/MoO 3 composites showed enhanced visible-light photocatalytic activity because of a V 3d impurity energy level and the formation of heterostructures at the interface between V2O5 and MoO 3. The optimal molar ratio of V to Mo in the V2O5/MoO 3 composites was found to be around 1/2. Furthermore,high-performance liquid chromatographic monitoring revealed that phthalic acid was the main intermediate in the photocatalytic degradation process of DMP.
文摘Dimethyl-1-(1, 2, 4-triazol) -2- butanone was treated with aqueous formaldehyde to give an additional product, and subsequent elimination by acetic anhydride yielded 4, 4-dimethyl-2-(1, 2, 4-triazol)-1-penten-3-one. Further addition with substituted amines provided a series of (1, 2, 4-triazol)-4, 4-dimethyl-3-pentanone, which were then reduced by KBH4 to obtain a series of (1, 2, 4-triazol)-4, 4-dimethyl-3-pentanol. Their structures were confirmed by 1HNMR and elemental analysis. The results of bioassay showed that the title products possess good fungicidal activities.
