新型酸性离子液体催化下甲苯的选择性硝化

用HNIL-NO_3~-和HNIL·HSO_4~-新型酸性离子液体为Lewis酸催化剂,考察了催化剂种类、用量、硝化反应时间、温度、醋酐等因素对甲苯选择性硝化反应的影响,并研究了催化剂的循环使用效果.结果表明,醋酐存在条件下,以CCl_4为溶剂、95%发烟硝酸为硝化剂,温度控制在55℃,反应60 min,3.0 g HNIL·HSO_4~-新型酸性离子液体催化剂对甲苯硝化表现出较强的区域选择性,产物收率达到99.4%,硝化产物邻位和对位异构体的重量比达1.12,较硝硫混酸的1.67显著降低.该催化剂可循环使用5次,催化活性变化很小.     

Preliminary studies on the use of modified ALCELL lignin as a coupling agent in the biofiber composites

ALCELL lignin has been employed as a coupling agent in empty fruit bunch fiber (EFBF)–polypropylene (PP) composites. The lignin has been chemically modified with toluene diisocyanate (TDI) to various weight loadings. The evidence of the reaction between TDI and lignin has been observed by using Fourier transform infrared (FTIR) analysis. The effect of lignin as a coupling agent on mechanical properties has been studied. The results show that the TDI‐modified lignin is able to impart greater compatibility between EFBF and PP. This is reflected in the greater mechanical properties shown by the composites with TDI‐modified lignin than in those with the unmodified lignin. Scanning electron microscopy (SEM) studies showed that TDI modification of lignin resulted in a better blending and compatibility between lignin and PP matrix. The glass‐transition temperature of the lignin increases as the WPG is increased. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1333–1340, 2001     

Interpolymer radical coupling: A toolbox complementary to controlled radical polymerization

The current review focuses on the relevance and practical benefit of interpolymer radical coupling methods. The latter are developing rapidly and constitute a perfectly complementary macromolecular engineering toolbox to the controlled radical polymerization techniques (CRP). Indeed, all structures formed by CRP are likely to be prone to radical coupling reactions, which multiply the available synthetic possibilities. Basically, the coupling systems can be divided in two main categories. The first one, including the atom transfer radical coupling (ATRC), silane radical atom abstraction (SRAA) and cobalt-mediated radical coupling (CMRC), relies on the recombination of macroradicals produced from a dormant species. The second one, including atom transfer nitroxide radical coupling (ATNRC), single electron transfer nitroxide radical coupling (SETNRC), enhanced spin capturing polymerization (ESCP) and nitrone/nitroso mediated radical coupling (NMRC), makes use of a radical scavenger in order to promote the conjugation of the polymer chains. More than a compilation of macromolecular engineering achievements, the present review additionally aims to emphasize the particularities, synthetic potential and present limitations of each system.     

A duplex coating composed of electrophoretic deposited graphene oxide inner-layer and electrodeposited graphene oxide/Mg substituted hydroxyapatite outer-layer on carbon/carbon composites for biomedical application

A duplex coating composed of electrophoretic deposited graphene oxide (GO) inner-layer and electrodeposited GO/Mg substituted hydroxyapatite (MH) outer-layer was prepared on carbon/carbon composites (CC). The morphology and microstructure of GO-GO/MH coating were researched by Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy. The bonding strength between GO-GO/MH coating and CC substrate was investigated by shear test. The in-vitro bioactivity of GO-GO/MH coating was analyzed by simulated body fluid (SBF) immersion test. The results demonstrated that electrophoretic deposited GO inner-layer was successfully introduced on CC and could serve as an interlayer between CC and following electrodeposited GO/MH outer-layer. GO/MH outer-layer presented a flake morphology with 150–250?nm in thickness and 1.5–2.5?µm in width, exhibiting porous three-dimensional networks structure uniformly. The shear test showed that the bonding strength between the duplex coating and CC reached 7.4?MPa, which was 80.49% higher than that of single-layered MH coating without GO. The duplex coating could induce the formation of flocculent and chapped apatite after SBF immersion, which demonstrated the in-vitro bioactivity of the duplex coating. These results suggested that GO-GO/MH coating might be a promising candidate in the field of biomaterials, especially for implant coatings.     

Highly soluble perylene dyes: Synthesis, photophysical and electrochemical characterizations

Highly soluble perylene diimide derivatives with symmetrical and unsymmetrical secondary, tertiary alkyl side chains were synthesized and their photophysical properties, redox potentials and thermal stabilities were measured and compared with previously reported 1-pentylhexyl substituted swallow-tailed perylene diimide. Diasteroisomers of the novel, unsymmetrical swallow-tailed substituted perylene diimide compound could not be detected using low temperature NMR spectroscopy. The novel dyes were soluble in a range of organic solvents indicating potential for photo-electronic applications and photocatalytic reactions. Two dyes were not only soluble in organic solvents but also showed solubility in aqueous media as the hydrochloride salt, thus offering potential use in biological applications.     

2，4－二磺酰胺－5－三氟甲基苯胺的合成及分析

介绍了由甲苯合成２，４－二磺酰胺－５－三氟甲基苯胺的方法，该合成方法中采用的催化加氢法还原硝基、环丁砜溶剂法胺基物磺化是较为先进的方法，采用高效液相色谱对产品进行定量分析，并介绍了流动相、储备相、标准物、分析样的制备方法。     

Heptane Dehydrocyclization Over Pt/KL Catalysts Doped with Barium or Lanthanum

Several 1 wt% Pt/KL catalysts doped with different concentrations of either BaO or La₂O₃ were prepared by successive impregnation of a zeolite KL and then characterized by H₂-O₂ titration, TPR, CO–FTIR, TEM-XEDS and XPS. Catalytic activity measurements in the hydroconversion of n-heptane showed that barium highly enhances the aromatization activity of Pt/KL, the more so the higher the barium concentration. The yield to aromatics increases to a lesser degree by adding 1 wt% La, but it is little modified at higher La concentrations. The CO–FTIR results suggest that the promoter effect of barium is related to an electron enrichment of Pt produced by the BaO Pt⁰ interaction which, according to the TEM–XEDS and XPS results, is more favored than the La₂O₃ Pt interaction.     

The Thermal Conductivity and Thermal Diffusivity of Liquid n-Alkanes: C n H2n+2 (n=5 to 10) and Toluene

Experimental values of the thermal conductivity and the thermal diffusivity of six pure liquid n-alkanes (C _n H_2n+2; n=5 to 10) and toluene are presented in the temperature range of –20 to 70°C under atmospheric or saturation pressure. Measurements were made with the transient hot-wire method, and in the analysis, the temperatures T and T (associated with both and ) were used. In the present work, the values of thermal diffusivity were corrected by the factors k _f (=1.0076 to 0.9892) for data sets obtained with different configurations of the experiment, in which the factors were determined by reference to the thermal diffusivity of n-heptane [= _s/(c _p )_s] at 298.15 K calculated from the volumic heat capacity (c _p )_s as a reference material for heat capacity and the experimentally obtained thermal conductivity _s. The uncertainty of the data is estimated to be 0.48% for the thermal conductivity (absolutely measured) and about 1.8% for the thermal diffusivity (with a coverage factor of k _p =2; p=95%).