One-pot synthesis of 5-hydroxymethylfurfural from glucose over zirconium doped mesoporous KIT-6

Zirconium doped mesoporous KIT-6 samples with different Si/Zr ratios were synthesized by the direct hydrothermal method.Various characterization techniques confirm that highly distributed ZrO_2 nanoparticles and multicoordinated Zr^(4+) species are incorporated in the mesoporous composites.One-pot synthesis of 5-hydroxymethylfurfura(HMF) from glucose was examined in the presence of Zr-KIT-6(20) the molar ratio of Si to Zr is 20 under aqueous system.The effects of temperature,reaction time,catalyst dosage and biphasic solvent system on the conversion of glucose and the HMF yield were investigated.It was found that the glucose conversion and the HMF yield have been improved from 54.8% to 79.0% and from 19.5% to 34.5% in the biphasic MIBK-water system,respectively.Both the acidity of Zr-KIT-6(20) and the biphasic MIBK-water system are responsible for the improved performance of glucose dehydration to HMF.

Controlled TiO2 coating on hollow glass microspheres and their reflective thermal insulation properties

Hollow glass microspheres(HGMs)have great potential in building energy-saving and industrial insulation.Anatase TiO2-modified HGMs were prepared by a sol-gel method in acetic acid-ethanol solution.Scanning electron microscopy,X-ray diffraction,zeta-potential measurements,nitrogen-sorption measurements,and Fourier-transform infrared and ultraviolet-visible-near-infrared diffuse reflectance spectroscopies showed that the alkali modification of the HGMs greatly influenced the loading and microstructure of the TiO2 film.The TiO2 loading could be accurately controlled by ethanol addition and the TiO2 coating time.A mechanism for the TiO2 coating of the HGM surface is proposed.The synergistic action of hydrogen bonding and electrostatic forces resulted in close contact between the HGMs and TiO2 sol at pH 3.5.The effects of different TiO2 loading rates on the reflective and thermal insulation properties were studied.The near-infrared reflectance of 15.9%TiO2 coated on HGMs was 96.27%,and the inner surface temperature of the composite pigment coated on aluminum board was reduced by 22.4℃.The TiO2/HGM composite pigments exhibited excellent solar reflective and thermal insulation properties,so have potential in the construction of exterior walls and roofs.

Hypoxia-induced activity loss of a photo-responsive microtubule inhibitor azobenzene combretastatin A4

The conformation-dependent activity of azo-benzene combretastatin A4(Azo-CA4)provides a unique approach to reduce the side-effects of chemotherapy,due to the light-triggered conformation transition of its azobenzene moiety.Under hypoxic tumor microenviron-ment,however,the high expression of azoreductase can reduce azobenzene to aniline.It was postulated that the Azo-CA4 might be degraded under hypoxia,resulting in the decrease of its anti-tumor activity.The aim of this study was to verify such hypothesis in HeLa cells in vitro.The quantitative drug concentration analysis shows the ratio-metric formation of degradation end-products,confirming the bioreduction of Azo-CA4.The tubulin staining study indicates that Azo-CA4 loses the potency of switching off microtubule dynamics under hypoxia.Furthermore,the cell cycle analysis shows that the ability of Azo-CA4 to induce mitotic arrest is lost at low oxygen content.Therefore,the cytotoxicity of Azo-CA4 is compromised under hypoxia.In contrast,combretastatin A4 as a positive control maintains the potency to inhibit tubulin polymer-ization and break down the nuclei irrespective of light irradiation and oxygen level.This work highlights the influence of hypoxic tumor microenvironment on the anti-tumor potency of Azo-CA4,which should be considered during the early stage of designing translational Azo-CA4 delivery systems.

A Lignin-Derived Carbonaceous Acid for Efficient Catalytic Hydrolysis of Cellulose

1A solid acid catalyst was prepared from masson pine alkali lignin in waste liquor of soda pulping by a combined process of chemical activation,carbonization,and sulfonation.The lignin-derived solid acid(LDSA)was characterized by FESEM,XRD,FTIR,TGA,XPS,BET analyses,and acid-base back titration.The carbonaceous material had high thermal stability and large specific surface area(488.4 m^(2)/g),and the structural analyses showed that it was composed of amorphous carbon bearing-SO_(3)H,-COOH,and phenolic-OH groups.The lignin-derived catalyst was then applied to the hydrolysis of a microcrystalline cellulose(MCC)in aqueous system,and the yield of total reducing sugars was found to be 46.1%.It was proposed that good adsorption capacities of cellulose and desorption property of glucose on LDSA probably contributed to efficient catalytic hydrolysis.