钛基金属-有机框架材料的改性及其催化性能研究

使用双氧水在一定温度下对钛基金属-有机框架材料NH2-MIL-125进行改性处理,制备得到一系列材料,系统地研究了改性方法及改性条件对材料性能的影响。结果表明,经改性处理后的材料,在可见光催化苯甲醇氧化反应中的催化速率有显著提高;同时,改性过程中的双氧水用量及改性温度对材料的结构、性质和光催化性能都有十分重要的影响。当双氧水为10 ml、改性温度为50℃时,改性材料具有优异的催化活性、选择性以及良好的稳定性,其催化速率与NH2-MIL-125相比提高近6倍。

Green Chemistry

Most manufactured products involve one or more chemical processes.Chemical industry provides us with numerous basic chemicals,materials,and energy products.It is well known that chemistry has made great contribution to the civilization of humankind,and will be more important in the future.However,many traditional chemical processes produce large amount

Green and Sustainable Chemistry

It is now a common opinion that sustainable development is a key issue to humanity. How to provide the population with sufficient clean water, food, chemicals, materials and energy without damaging our planet is an extremely important

Robust Carbon-Carbon Cleavage in Lignin to Produce Phenol and Cyclohexanone

The challenge of breaking 5-5'bonds in lignin,attributed to their high bonding energy,has prompted the development of a new transformation pathway.Biphenyl,an important model compound for lignin,contains these 5-5'bonds,making it crucial to devise a strategy for their cleavage in lignin transformation.This study introduces a novel method for transforming biphenyl,involving selective hydrogenation to cyclohexylbenzene by Ni/SiO2 catalyst,followed by its oxidation to phenol and cyclohexanone through a radical mechanism.Results demonstrate that the catalysts with small particles have strong catalytic activity,while there is little difference in selectivity.The reason for the high selectivity of cyclohexylbenzene is due to the limited adsorption of cyclohexylbenzene on Ni/SiO2.This work presents a fresh approach to breaking resilient C-C bonds in lignin.

CO_(2)/NOx-involved Electrochemical C-N Coupling Reactions

With the excessive use of fossil fuels leading to significant CO_(2)emissions,and the continuous increase of NOx in water bodies and soils,the use of electrochemical methods for the conversion of CO_(2)and NOx has garnered widespread attention as a green chemical approach due to its advantages of being environmentally friendly,low-carbon,and straightforward.C—N bonds are widely present in many value-added chemicals,such as urea,amides,and oximes.However,traditional methods for constructing C—N bonds typically involve thermochemical processes.Therefore,using electrochemical methods to catalyze the reduction of CO_(2)and NOx for C—N bond formation has emerged as a green and sustainable alternative.This paper summarizes the research progress of electrochemical C—N bond construction involving CO_(2)and NOx from the perspectives of reaction mechanisms and catalytic system construction,reviews the electrochemical synthesis of urea,amines,amides,and oximes through electrochemical C—N bond construction,and finally analyzes the current problems and challenges in the field,providing prospects for its future development.

复杂流体中新型材料的合成反应过程实时跟踪研究

复杂流体在新型材料合成、机械、智能控制、催化、医药、生物、环境等诸多领域有着非常重要的应用前景。目前,复杂流体中微观结构随外场的演化及复杂流体中个体间的复杂耦合作用尚不清楚,这严重制约着复杂流体的开发和应用。复杂流体中组元间的耦合作用、微观结构随外场的演化规律以及结构与性能的内在联系是复杂流体科学面临的关键科学问题,其研究亟需原位实验技术予以支撑。该研究拟建立基于同步辐射光源的X射线吸收(XAFS)/X射线衍射(XRD)联用技术、小角X射线散射(SAXS)/广角X射线散射(WAXS)/XAFS联用技术、SAXS/WAXS/拉曼光谱(Raman)联用技术、SAXS/WAXS/红外光谱(IR)联用技术、掠入射小角X射线散射(GISAXS)/紫外可见吸收光谱(UV-Vis)联用技术,开发适用以上联用技术的复杂流体原位研究样品环境(包括温度、压力、电场、剪切力场、混流、浓度等),用于跟踪复杂流体中原子、分子、纳米尺度结构基团等随外场的变化,揭示复杂流体中结构演化机制,并最终通过控制结构,达到改善和调控复杂流体性质的目的。

The physicochemical properties of some imidazolium-based ionic liquids and their binary mixtures

The density, viscosity and conductivity of ionic liquids （ILs）, 1-octyl-3-methylimidazolium tetrafluoroborate （[omim][BF4]）, 1-octyl-3-methylimidazolium chloride （[omim][C1]）, 1-hexyl-3-methylimidazolium tetrafluoroborate （[hmim] BF4]）, 1-hexyl- 3-methylimidazolium chloride （[hmim][C1]）, 1-hexyl-3-methylimidazolium hexafluorophosphate （[hmim][PF6]）, and the [omim][BF4] ＋ [omim][Cl], [hmim][BF4] ＋ [hmim][C1], and [hmim][PF6] ＋ [hmim][C1] binary mixtures were studied at dif- ferent temperatures. It was demonstrated that the densities of both the neat ILs and their mixtures varied linearly with temper- ature. The density sensitivity of a binary mixture is between those of the two components. The excess molar volumes （l/e） of [hmim][BF4] ＋ [hmim][C1] and [hmim][PF6] ＋ [hmim][C1] mixtures are positive in the whole composition range. For [omim][BF4] ＋ [omim][C1], the VE is also positive in the [omirn][C1]-rich region, but is negative in the [omim][BF4]-rich re- gion. The viscosity or conductivity of a mixture is in the intermediate of those of the two neat ILs. For all the neat ILs and the binary mixtures studied, the order of conductivity is opposite to that of the viscosity. The Vogel-Tammann-Fulcher （VTF） equations can be used to fit the viscosity and conductivity of all the neat ILs and the binary mixtures. The neat ILs and their mixtures obey the Fractional Walden Rule very well, and the values of the Walden slopes are all smaller than unit, indicating obvious ion associations in the neat ILs and the binary mixtures.

Characterization of refractive index distribution of polymer optical fiber

A focusing method is developed to characterize the refractive index profile of polymer optical fiber (POF). Based on the refractive index profile the theoretical bandwidth and the core index exponent a (a 】 0) of POF are calculated. The results show that the value of theoretical bandwidth agrees well with the experimental data.

Efficient dehydration of carbohydrates to 5-hydroxymethylfurfural in ionic liquids catalyzed by tin(Ⅳ) phosphonate and zirconium phosphonate

In this work,we synthesized tin(IV)phosphonate(SnBPMA)and zirconium phosphonate(ZrBPMA)by the reaction of SnCl4·5H2O or ZrOCl2·8H2O with N,N-bis(phosphonomethyl)aminoacetic acid,which was synthesized from a biomaterial glycine through a Mannich-type reaction.The SnBPMA and ZrBPMA were very efficient heterogeneous catalysts for the dehydration of fructose to produce 5-hydroxymethylfurfural(HMF),and the SnBPMA had higher activity than the ZrBPMA.The effects of solvents,temperature,reaction time,and reactant/solvent weight ratio on the reaction catalyzed by SnBPMA were investigated.It was demonstrated that the yield of HMF could reach 86.5%with 1-ethyl-3-methylimidazolium bromide([Emim]Br)as solvent,and the SnBPMA and SnBPMA/[Emim]Br catalytic system could be reused five times without considerable reduction in catalytic efficiency.Further study indicated that the SnBPMA and ZrBPMA in[Emim]Br were also effective for the dehydration of sucrose and inulin to produce HMF with satisfactory yields.

Chirality Inversion of Assemblies of Bio-based Surfactant Triggered by Metal Ions

The utilization of biomass has attracted much attention during the last decade. Sorbitol is a kind of abundant biomass with multiple chiral centers in its skeleton, indicating an im- portant potential for helical architectures. Helical nanostruc- tures with switchable chirality are attracting much attention due to their crucial roles in many fields.

Acceleration of disproportionation reactions of aryl alcohols in water medium by CO_2

Compressed CO~ could promote the disproportionation reactions of aryl alcohols in water medium significantly. The control experiments indicated that the effect of CO2 on the properties of the reactant/water emulsions was the main reason for the ac- celeration of the reactions rate.

Bimetallic Au/Pd catalyzed aerobic oxidation of alcohols in the poly(ethylene glycol)/CO_(2) system

Bimetallic Au/Pd nanoparticles were prepared and used to catalyze oxidation of alcohols in the poly(ethylene glycol) (PEG)/CO_(2) biphasic system using O2 as the oxidant without adding any base.The catalytic activity of Au/Pd bimetal with different mole ratios was studied using benzyl alcohol as the substrate.It was found that bimetallic Au/Pd nanoparticles with Au:Pd=1:3.5 had higher catalytic activity than monometallic Au,Pd and the bimetallic Au/Pd nanoparticles with other molar ratios.The effect of CO_(2) pressure on the oxidation of benzyl alcohol and 1-phenylethanol in PEG/CO_(2) was investigated.It was demonstrated that CO_(2) pressure could be used to tune the conversion and selectivity of the reactions effectively.α,β-Unsaturated alcohols were also studied and found to be more reactive than benzyl alcohol and 1-phenylethanol.Recycling experiments showed that the Au/Pd/PEG/CO_(2) catalytic system could be recycled at least four times without reducing the activity.In addition,the catalytic system is clean and the products can be separated easily.

Large Scale Synthesis of Transition Metal Single Atom Catalysts by a Universal Ligand Mediated Method

Series of transition metal single atom catalysts containing Cr,Mn,Fe,Co,Ni,Cu,Zn,Ru,Pt or combinations thereof were synthesized in a large scale by a universal ligand mediated method.The as-synthesized single atom catalysts exhibited excellent electrochemical CO2 reduction activity.

A Synthetic Strategy of Ultrathin High-κ Antimony Oxide Single Crystals

UItrathin antimony oxide single crystals with high dielectric constant and large breakdown electric field were synthesized via an expressly substrate-buffer-controlled chemical vapor deposition strategy.This strategy is also versatile for the svnthesis of other ultrathin oxides.