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In the context of the implementation of the global “plastic restriction order” and the driving force of environmental and green protection,butane-1,4-diol (BDO),as a crucial and natural degradable raw material,is anticipated to receive significant attention from industrial and market sectors.Moreover,BDO is also an important organic raw material,showing widespread applications extend across multiple key fields such as medicine,textile industry,electronic materials,as well as engineering plastics.Here,this review summarizes the major synthetic methods of BDO and the development of its high-value-added products.Meanwhile,the key problems in the industry preparation process of BDO were discussed,additionally,the merits and demerits in each process flow were also put into deep insight.Finally,prospects were put forward for the BDO-industry development combined with the national characteristics and actual situation.
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Rhodamine B is a typical organic dye pollutant,which can cause water environment pollution.It is of great practical significance to study its degradation in water protection.In this study,3 946 articles were retrieved from the Web of Science database using subject words.VOSviewer software was used to analyze the co-occurrence of keywords,authors,institutions and other elements of the retrieved literature and link the research content of the CNKI database to construct an academic knowledge map.The visual analysis of the degradation of rhodamine B aims to reveal the characteristics of research countries,research institutions,research hotspots,core research fields and cooperation networks in this field,and provide theoretical reference for subsequent research work.The analysis results show that China is the country with the largest number of publications in the field of degrading rhodamine B in the past ten years.The keyword clustering presents a multi-research pattern.Through analysis,the research hotspots are gathered in bismuth aluminum oxide,heterojunction structure,nano-materials,degradation performance,TiO2 and so on.Nanomaterials and heterojunction structure will become a better development direction in the future.
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Ester hydrogenation reaction plays a crucial role and is a key step in the synthesis of various high value-added chemicals in modern chemical industry.Especially,in the process route of coal to ethanol and ethylene glycol,the hydrogenation of methyl acetate and dimethyl oxalate is the core step of the process,which is of great significance for promoting the diversification and clean development of coal resources in China.Copper based catalysts are widely used in industrial production for ester hydrogenation reactions due to their advantages of low cost and high selectivity.However,due to the low Tammann temperature of Cu,copper based catalyst nanoparticles (NPs) are prone to aggregation,leading to a decrease in activity.In order to achieve space-time yield in industrial production,it is necessary to increase the reaction temperature,which accelerates the deactivation of copper based catalysts.Researchers usually use methods such as doping additives and developing morphology confinement to hinder the high-temperature aggregation of Cu NPs,in order to maintain the activity of the catalyst and improve its service life.This article elaborates on the mechanism of action of copper based catalysts and the influencing factors of ester hydrogenation reactions.It reviews the research progress of copper based catalysts for ester hydrogenation and introduces typical industrial applications of ester hydrogenation.
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Developing long-life and low-cost electrolytes is one of the key challenges for realizing the commercialization of zinc-air batteries for unmanned aerial vehicles (UAVs).In this work,a hydrophilic silicone oil/zinc acetate mixed electrolyte is prepared by physical mixing method.The process is simple,and the raw material cost is reduced by about 30% compared with the traditional 6 mol/L KOH system.The zinc-air battery with 1 mol/L zinc acetate and hydrophilic silicone oil mixed electrolyte system has a cycle life of 400 h at 0.2 mA/cm2,which is 1.38 and 2.86 times of 1 mol/L zinc acetate aqueous solution (290 h) and 6 mol/L KOH electrolyte (140 h),respectively.The mixed electrolyte not only possesses the high conductivity of zinc acetate electrolyte but also has the characteristic of hydrophilic silicone oil to inhibit electrolyte volatilization,thereby significantly extending the service life of zinc-air batteries.The zinc-air battery with a mixed electrolyte system exhibits a low internal resistance (25 Ω) and a high-power density (44.3 mW/cm2),approaching those of the 6 mol/L KOH solution system (15 Ω,47.2 mW/cm2).The hybrid power system of this zinc-air battery and lithium-ion battery achieves a power-to-weight ratio of 33 mN/g,representing a 12% increase compared to single lithium batteries.This enables a 20% extension in the flight duration of quadrotor drones,with stable power output maintained at 2.5 W.This study provides a novel strategy for electrolyte design of zinc-air batteries,featuring long lifespan,low cost,and high stability.The mixed electrolyte system demonstrates remarkable application potential in the fields of long-life energy storage and drone power sources.
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The selective hydrogenation of α,β-unsaturated carbonyl compound and maleic anhydride to produce high value-added product γ-butyrolactone (GBL) is of great scientific research significance and practical application value.Due to the conjugation between C=C and C=O groups in the maleic anhydride molecule,the key to achieving high product selectivity lies in the rational design of heterogeneous catalysts.In this work,Co was introduced into Ni-based catalysts using a simple co-impregnation method,significantly improving the GBL selectivity from 53.5% over 5Ni/SiO2,7.2% over 4Co/SiO2,to 82.2% over 5Ni-4Co/SiO2.Combined with characterization results from XRD,H2-TPR,H2-TPD,HRTEM,and XPS,structure-activity relationship analysis revealed that the NiCo alloy on the surface of Ni-Co/SiO2 catalyst could enhance the hydrogen activation capability of the catalyst,while the oxygen vacancies generated through the mutual promotion of Ni and Co reduction serve as active centers for adsorbing and activating the C=O groups in maleic anhydride molecules.The synergistic effect of several active centers including NiCo alloy,Ni0,Co0,and oxygen vacancies accomplishes C=O hydrogenation,promoting the highly selective conversion of maleic anhydride to GBL.
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Honeycomb Pd-based alumina and silica coating catalysts were used to investigate the effects of different carrier coating catalysts on the catalytic oxidation performance of methane before and after high-temperature treatment.The experimental results show that at a volumetric space velocity of 20 000 h-1 and a methane mass concentration of 2 000 mg/m3,the Pd/Al-550 catalyst can achieve methane conversion of 90% and 99.6% at 400 ℃and 500 ℃,respectively,which is superior to the Pd/Si-550 catalyst (26.5% and 99.4%).Analysis and characterization results indicate that the Pd/Al-550 catalyst has a higher number of Pd2+ species,a higher proportion of surface adsorbed oxygen (Oads/Olat),and stronger surface acidity compared to the Pd/Si-550 catalyst.After high-temperature treatment at 700 ℃,the methane conversion of the Pd/Al-700 catalyst and the Pd/Si-700 catalyst decreased to 90.1% and 65.0% at 500 ℃,respectively.The size and dispersion of the noble metal particles did not change significantly.The decrease in the number of Pd2+ species,the proportion of surface adsorbed oxygen (Oads/Olat),and the surface acidity may be the reasons for the decline in methane conversion of the catalysts.
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BiOCl nanosheets were prepared via a hydrothermal approach,and their piezoelectric photocatalytic degradation efficiency toward levofloxacin was thoroughly examined.The crystalline structure,surface morphology,and light absorption characteristics of BiOCl were systematically analyzed by XRD,SEM and ultraviolet diffuse reflection spectroscopy.The results show that the prepared nanosheet BiOCl has a tetragonal crystal phase structure and a band gap width of 3.04 eV.Under the combined effect of 300 W xenon lamp and ultrasonic waves,the degradation efficiency of 10×10-6 levofloxacin solution by BiOCl for 40 min is as high as 99.90%.Its reaction rate constants are 4.6 times and 13.89 times of that of single photocatalysis and piezoelectric catalysis respectively,significantly surpassing the simple superposition of the two performances.It has been confirmed that there is a strong coupling effect between piezoelectric catalysis and photocatalysis.The cyclic experiment shows that the degradation efficiency remains at 85.45% after five repeated uses,demonstrating excellent stability.This study provides a theoretical basis for the efficient removal of antibiotic pollutants in the environment and the practical application of piezoelectric photocatalytic technology.
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By doping metal Cu and Ni to modify CeO2-ZrO2,the effects of depositiion-precipitation method,hydrothermal method,microwave hydrothermal method,equal volume impregnation method,and template method on the structure and performance of the catalyst were compared.It was found that the catalyst synthesized by the template method (CTAB-NaOH) exhibited solid solution oxide characteristics,along with numerous oxygen vacancies,acid-base active sites,a large specific surface area,and a low reduction potential.It showed extremely high activity in the direct synthesis of DMC from CO2 and methanol.Under the conditions of 160 ℃,4 MPa,space velocity of 6 h-1,and hydrophilic SiO2 as a dehydrating agent,the methanol conversion reached 39.1%,and the DMC yield reached 38.9%.
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The direct synthesis of dimethyl carbonate (DMC) from CO2 and methanol is considered an environmentally benign and highly atom-efficient approach.The development of efficient catalysts,particularly metal oxide catalysts,has consistently been a focal point in this synthesis methodology.In this study,CuO-ZrO2 catalysts (Cu/Zr-1,Cu/Zr-2,Cu/Zr-3) with Cu/Zr molar ratios of 1∶1,1∶2,and 1∶3 were synthesized using copper(Ⅱ) sulfate pentahydrate and zirconium(Ⅳ) nitrate pentahydrate as precursors via the urea precipitation-hydrothermal method.These catalysts were employed to facilitate the direct reaction of CO2 and CH3OH for DMC production.The structural and compositional characteristics of the catalysts were systematically investigated using Fourier transform infrared spectroscopy (FT-IR),X-ray powder diffraction (XRD),ultraviolet-visible spectroscopy (UV-Vis) and N2 adsorption-desorption isotherms (BET-BJH).The results demonstrated that the yield of DMC initially increased and subsequently decreased with increasing copper content.Notably,DMC yield of the Cu/Zr-2 catalyst peaked at 0.47 mmol/gcat,indicating the superior catalytic activity of the CuO-ZrO2 catalyst prepared by the urea precipitation-hydrothermal method.The Cu/Zr molar ratio significantly influenced the hydroxyl groups on the catalyst surface,electron transfer between metal oxides,pore structure,specific surface area,and crystal structure.Specifically,at a Cu/Zr molar ratio of 1∶2,the catalyst exhibited the largest specific surface area (77.27 m2/g),an optimal pore size of 3.59 nm,and a relatively abundant surface hydroxyl group density.
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2-tert-Pentylanthracene is a key intermediate in the anthraquinone process for hydrogen peroxide production.Conventional synthesis of 2-tert-pentylanthracene using AlCl3 suffers from difficulties in catalyst recovery and significant environmental pollution,necessitating the development of greener and more sustainable catalytic systems.In this work,β zeolite was modified via phosphoric acid treatment,and the effects of phosphoric acid concentration,impregnation time,and number of impregnation cycles on the alkylation of anthracene to produce 2-tert-pentylanthracene were systematically investigated.The results indicate that treating β zeolite with 1 mol/L phosphoric acid at 80 ℃ under stirring for 1 h (single impregnation) effectively enhances its specific surface area,pore volume,and pore size,while simultaneously increasing the total surface acidity and tuning the ratio of Brønsted (B) to Lewis (L) acid sites.Using β zeolite modified under the optimized conditions,the yield of 2-tert-pentylanthracene was 38.51% when the dosage of dichloromethane was 10 mL/g,n(anthracene)∶n(tert-amyl alcohol)=0.208∶0.208,catalyst dosage of 0.5 g,reaction time of 3 h,and reaction temperature of 160 ℃.
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The supported skeleton nickel adsorbents were prepared by nickel-aluminum powder and pseudo-boehmite through molding,drying,calcination and alkaline leaching activation.The adsorbents were characterized by XRD,SEM,H2-TPR,N2 adsortion-desorption,and their adsorptive performances were evaluated by removing trace amount of thiophene in benzene.The results indicated that compressive strength and desulfuration performance of supported skeleton Ni adsorbents were affected by calcination atmosphere and leaching time.The adsorbents calculated in argon exhibited better compressive strength and performance than those calculated in air.As a result,the compressive strength of adsorbent was 26.10 N/mm. Besides,longer leaching time resulted in lower compressive strength and better adsorption capacity.However,compressive strength dramatically decreased as a result of extremely long leaching time.After calcinating at 860 ℃ in argon for 4 h and leaching at 60 ℃ in 15%NaOH (mass fraction) aqueous solution for 4 h,the saturated adsorption capacity of as-prepared adsorbent was 37.08 mg/g and it presented excellent performance by removing all thiophene in benzene at T=180 ℃,P=2.0 MPa and WSHV=2 h-1.
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Using 1,2-dichloroethane as the solvent,triethylamine and bromoethane as the reaction raw material,the phase transfer catalyst tetraethylammonium bromide was synthesized by solvent method under heating and reflux conditions.The effects of reaction raw materials molar ratio,solvent dosage,reaction temperature,reaction time,stirring speed and solvent application on the product were explored.The experimental results showed that when the molar ratio of triethylamine and bromine ethane was 1∶1.1,the molar ratio of solvent to triethylamine was 2.5,the reaction temperature was 70 ℃,the reaction time was 4 h and the rotation speed was 300 r/min,the yield of product was stable,the product purity reached more than 99%.The solvent application had no effect on the product purity.
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Industrial flue gases from typical metal smelting and coal chemical processes contain certain amounts of copper particles and mercury droplets.However,their impact on corona discharge during electrostatic precipitation remains unclear.This study quantitatively examines the influence of copper particles and mercury droplets on current during corona discharge.The results reveal that within the probable concentration range in industrial flue gases,varying mass concentrations of these substances suppress corona discharge to different extents.Significant suppression occurs when the mass concentration exceeds 50 g/m3,and discharge electrodes cease functioning at 500 g/m3.Compared to mass concentration,copper particle/mercury droplet sizes have a relatively minor effect,with discharge currents maintaining above 88%.
