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Comparative study of microwave-assisted versus conventional heated reactions of biomass conversion into levulinic acid over hierarchical Mn_(3)O_(4)/ZSM-5 zeolite catalysts

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Carbon Resources Conversion 2023年第3期6卷 245-252页

作者： Mazizah R.A.Helmi Dyah Utami C.Rahayu Arnia P.Pratama Irena Khatrin Anita N.Ramadhani Yuni K.Krisnandi department of chemistry Faculty of Mathematics and Natural ScienceUniversitas IndonesiaDepok 16424Indonesia Solid Inorganic Framework Laboratory Department of ChemistryFaculty of Mathematics and Natural ScienceUniversitas IndonesiaDepok 16424Indonesia

Conversion of delignified cellulose from rice husk biomass,and model compounds of cellobiose and glucose to levulinic acid(LA)over hierarchical Mn_(3)O_(4)/ZSM-5 catalyst was carried out using a household microwave method,and then compared to the established conventional thermos-reaction *** hierarchical ZSM-5 was prepared using a double template method,aiming for micro and mesoporous systems developed in the *** as-prepared ZSM-5 were modified with Mn3O4 through incipient wetness impregnation with Mn2+solution followed by calcination at 550℃.The catalysts were characterized using various techniques such as powder XRD,SEM,BET,AAS,and FT-IR which indicated the hierarchical structure of MFI zeolite(Si/Al of 30-34)with Mn loading of 2.14 wt%.The conversion products were analyzed using HPLC,1H NMR,and 13C NMR *** microwave-assisted reaction using 600 W for 180 s using delignified cellulose,cellobiose,and glucose gave conversion of 37.27%,46.35%,and 54.29%,respectively which is close to the conversion given by the conventional reaction carried out at 130◦C for 4 h(36.75%,55.62%,and 60.9%,respectively).Interestingly,the LA yield from the microwave-assisted reaction(4.33%,6.12%,and 9.57%)is higher than the yield from the conventional reaction,which only produced 5.2%,4.88%,and 6.93%*** microwaveassisted method is also shown to give less by-products compared to the thermochemical ***,it could be considered an alternative method for converting cellulose to LA.

关键词： Hierarchical ZSM-5 zeolite Levulinic acid Lignocellulose conversion Microwave-assisted synthesis Cellobiose Glucose

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Distereoselective one-pot synthesis of pyrimidopyrimidines using sulfated tin oxide as a reusable catalyst:An extension of Biginelli-type reaction

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Chinese Chemical Letters 2013年第12期24卷 1070-1074页

作者： Rupali L.Magar Prashant B.Thorat Pratima B.Thorat Vinod V.Thorat Bhagawan R.Patil Rajendra P.Pawar department of chemistry Deogiri College department of chemistry Dnyanopasak College department of chemistry Sharda Mahavidyalaya

The Biginelli-type compounds 4,5,8a-triarylhexahydropyrimido[4,5-d]pyrimidine-2,7（1H,3H）-diones were synthesized by a one-pot three-component reaction using sulfated tin oxide as a reusable catalyst. This method has the advantages of high yields, short reaction time, simple starting materials and reusability of catalyst for several times.

关键词： Biginelli-type reaction Multicomponent reactions Pyrimido[4 5-d]pyrimidine Sulfated tin oxide Reusable catalyst

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A new nanocluster polyoxomolybdate [Mo_(36)O_(110)(NO)_4(H_2O)_(14)]·52H_2O:Synthesis, characterization and application in oxidative degradation of common organic dyes

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Chinese Journal of Chemical Engineering 2018年第2期26卷 337-342页

作者： Mojtaba Amini Mostafa Khaksar Arkady Ellern L.Keith Woo department of chemistry Faculty of ScienceUniversity of Maragheh chemistry department Iowa State University

Polyoxomolybdate [Mo36O110（NO）4（H2O）14].52H2O was synthesized by a simple one-pot procedure through reducing an acidified mixture of Na2MoO4.2H2O and NH2OH. HCl. In order to create a heterogeneous catalyst system, the polyoxomolybdate was pillared with MgAI-LDH-NO3 by direct ion exchange. These novel materials were carefully analyzed by various chemico-physical methods, The catalytic degradation of methylene blue （MB） and rhodamine B （RB） as common dyes in the presence of MgAl-LDH-1 nanoparticles with aqueous hydrogen peroxide, H2O2, as an oxidizing agent was studied in aqueous solution at room temperature. More importantly, the catalyst can be recovered and reused efficiently up to five consecutive cycles with negligible loss of catalytic activity.

关键词： Nanocluster Polyoxomolybdate LDH Methylene blue Rhodamine B

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Synthesis,spectroscopic characterization,DNA cleavage and antibacterial studies of a novel tridentate Schiff base and some lanthanide(III) complexes

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Journal of Rare Earths 2014年第4期32卷 379-388页

作者： K.Mohanan R.Aswathy L.P.Nitha Niecy Elsa Mathews B.Sindhu Kumari department of chemistry University of Kerala department of chemistry Mother Teresa Women's University

A novel potential tridentate Schiff base was prepared by condensing equimolar quantities of 2-hydroxyacetophenone and 2-aminopyrimidine in methanol. This ligand was versatile in forming a series of complexes with lanthanide ions such as La（III）, Pr（III）, Nd（III）, Sm（III）, Gd（III）, Dy（III） and Yb（III）. The ligand and the metal complexes were characterized through elemental analysis, molar conductance, UV-Visible, IR, 1H NMR, and mass spectral studies. The spectral studies indicated that the ligand was coordinated to the metal ion in neutral tridentate fashion through the azomethine nitrogen, one of the nitrogen atoms in the pyrimidine ring and the phenolic oxygen without deprotonation. Thermal decomposition and luminescence property of lanthanum（III） complex were also examined. The X-ray diffraction patterns showed the crystalline nature of the ligand and its lanthanum（III） complex. The DNA cleavage studies of the ligand and the metal complexes were carried out and it was observed that the lanthanum（III） and neo-dymium（III） complexes cleaved the pUC19 DNA effectively. The ligand and the metal complexes were screened for their antibacte-rial activities. The metal complexes were found to be more potent bactericides than the ligand.

关键词： 2-aminopyrimidine lanthanides thermogravimetry luminescence DNA cleavage antibacterial activity rare earths

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Correlation between the molecular structure and transcis isomerization characteristics of azobenzenes

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Science China chemistry 2011年第12期54卷 1955-1961页

作者： HAN Mina HONDA Takumu department of chemistry and department of Electronic chemistry Tokyo Institute of Technology

Photochemical and thermal isomerization of various azobenzenes was systematically investigated to understand the correlation between the molecular structure and trans → cis isomerization characteristics of azobenzenes. A blue shift in π-π absorption band of ortho-alkylated azobenzenes （1o and 2o） was observed together with a reduction in molar extinction coefficient （e） in comparison with both meta-alkylated azobenzenes （4m and 5m） and 7p lacking the meta and ortho substituents. For orthoalkylated azobenzene, photochemical trans-to-cis isomerization and thermal back cis-to-trans isomerization in solution oc- curred slowly when compared with 4m, 5m and 7p. The half-life time of the cis form of 20 was found to be 380 h, which is about 8-50 times longer than those of comparable 4m, 5m （43-13 h） and 7p （7 h）. Furthermore, comparison of the molecular structure and isomerization characteristics of azobenzene thiol （20 and 5m） self-assembled monolayers on flat gold surfaces indicates that the trans-to-cis photoconversion in monolayer systems is influenced by steric hindrance and strong intermoleculax interaction between azobenzene units.

关键词： azobenzene isomerization lifetime of cis form molecular structure

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Synthesis of a PEG-PNIPAm Thermosensitive Dendritic Copolymer and Investigation of Its Self-association

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Chinese Journal of Polymer Science 2015年第1期33卷 192-202页

作者： Farzad Seidi Parvin Heshmati department of chemistry Sanandaj Branch Islamic Azad University University of Kurdistan Department of Chemistry

A Novel thermosensitive dendritic copolymer based on polyethylene glycol（PEG） and poly（Nisopropylacrylamide）（PNIPAm） with a cloud point（CP） around 36 ？C was successfully synthesized by preparation of a dendritic polyol and followed by atom transfer radical polymerization（ATRP） of N-isopropylacrylamide. The dendritic copolymer was characterized using gel-permeation chromatography（GPC）, FTIR and 1H-NMR spectroscopy. The selfassociation behavior of the copolymer in aqueous medium was investigated by dynamic light scattering（DLS） and transmission electron microscopy（TEM）. These investigations confirmed that the dendritic copolymer showed different association behaviors at various temperatures.

关键词： Thermosensitive Dendritic Atom transfer radical polymerization Poly(N-isopropylacrylamide) Polyethylene glycol.

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Metal-containing nanomaterials as lubricant additives: State-of-the-art and future development

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Friction 2019年第2期7卷 93-116页

作者： Igor E.UFLYAND Vladimir A.ZHINZHILO Victoria E.BURLAKOVA department of chemistry Southern Federal University department of chemistry Don State Technical University

This review focuses on the effect of metal-containing nanomaterials on tribological performance in oil lubrication. The basic data on nanolubricants based on nanoparticles of metals, metal oxides, metal sulfides, nanocomposities, and rare-earth compounds are generalized. The influence of nanoparticle size, morphology, surface functionalization, and concentration on friction and wear is analyzed. The lubrication mechanisms of nanolubricants are discussed. The problems and prospects for the development of metal-containing nanomaterials as lubricant additives are considered. The bibliography includes articles published during the last five years.

关键词： coefficient of friction metal-containing nanomaterials nanolubricants nanoparticles wear

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A Study of the Relation between Current Oscillations and Pitting

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Chinese Journal of chemistry 2003年第10期21卷 1309-1314页

作者：马厚义尹秉胜李桂燕郭文娟陈慎豪唐凯 department of chemistry

Anodic polarization behaviors of iron in pure H 2SO 4 and three mixed acidic solutions, H 2SO 4+NaCl, H 2SO 4+NaNO 3 and H 2SO 4+NaCl+NaNO 3, were investigated. The potentiodynamic sweep curves showed that the current densities rose and dropped irregularly in H 2SO 4+NaCl solution at the more anodic potentials since the iron surface suffered pitting attack in the solution, but the pitting corrosion was inhibited effectively in the presence of nitrate ions. The surface morphological measurements indicated that pits appeared on the iron surface in H 2SO 4+NaCl solution and only a few unobvious corrosion spots were observed in H 2SO 4+NaCl+NaNO 3 solution after the iron electrode was potentiostatically polarized at 1 3 V. The oscillatory properties of iron are associated with the susceptibility of the iron to pitting. In H 2SO 4+NaCl solution, the regular potentiostatic current oscillations gradually evolved into the irregular current fluctuations due to occurrence of the pitting; whereas in H 2SO 4+NaCl+NaNO 3 solution, the current oscillations took place regularly, like the oscillatory behavior in the pure H 2SO 4 solution. Thus, when the higher the oscillatory frequency, the more irregular oscillatory process and the more sensitive to pitting iron occurred.

关键词： current oscillation pitting iron oscillatory frequency passivation

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Bond Valence Sum Analysis of Tl(Ⅰ) and Tl(Ⅲ) Complexes with O and N Donors

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Chinese Journal of Structural chemistry 2011年第12期30卷 1820-1826页

作者： Gus J.Palenika 胡盛志 chemistry department The University of Florida department of chemistry Institute of Physical ChemistryXiamen University

The influence of the lone pair of electrons in thallium complexes is analyzed using the bond valence sum *** length data for metal-organic Tl complexes were obtained from the Cambridge Structural Database（CSD）,and problems with searching the CSD file for Tl complexes are *** recommended R0 values for Tl（Ⅰ）-O of 2.162 ,Tl（Ⅲ）-O of 2.016 ,Tl（Ⅰ）-N of 2.286 ？,and for Tl（Ⅲ）-N of 2.014  used with b = 0.37 were derived from analyses of homoleptic Tl-O,Tl-N,and heteroleptic Tl-O and-N metal organic *** R0 values can be used to assign correctly the oxidation state of Tl in complexes containing any combination of Tl-O or Tl-N *** of questionable oxidation states for Tl complexes are *** R0 value for Tl（Ⅲ）-Cl of 2.300  was also determined.

关键词： thallium complex oxidation state bond valence parameter crystal structure

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High‑Entropy Electrode Materials:Synthesis,Properties and Outlook

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Nano-Micro Letters 2025年第1期17卷 472-506页

作者： Dongxiao Li Chang Liu Shusheng Tao Jieming Cai Biao Zhong Jie Li Wentao Deng Hongshuai Hou Guoqiang Zou Xiaobo Ji College of chemistry and Chemical Engineering Central South UniversityChangsha 410083People’s Republic of China School of chemistry and Chemical Engineering Hunan Institute of EngineeringXiangtan 411104People’s Republic of China

High-entropy materials represent a new category of high-performance materials,first proposed in 2004 and extensively investigated by researchers over the past two *** definition of high-entropy materials has continuously *** the last ten years,the discovery of an increasing number of high-entropy materials has led to significant advancements in their utilization in energy storage,electrocatalysis,and related domains,accompanied by a rise in techniques for fabricating high-entropy electrode ***,the research emphasis has shifted from solely improving the performance of high-entropy materials toward exploring their reaction mechanisms and adopting cleaner preparation ***,the current definition of high-entropy materials remains relatively vague,and the preparation method of high-entropy materials is based on the preparation method of single metal/low-or medium-entropy *** should be noted that not all methods applicable to single metal/low-or medium-entropy materials can be directly applied to high-entropy *** this review,the definition and development of high-entropy materials are briefly ***,the classification of high-entropy electrode materials is presented,followed by a discussion of their applications in energy storage and catalysis from the perspective of synthesis ***,an evaluation of the advantages and disadvantages of various synthesis methods in the production process of different high-entropy materials is provided,along with a proposal for potential future development directions for high-entropy materials.

关键词： High-entropy Energy storage Electrode materials

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