A composite material was synthesized at room temperature by performing modification of the copper benzene-1,3,5-tricarboxylate (HKUST-1) metal-organic framework material by multilayer fluorinated graphene (FG). The FG-HKUST-1 composite was used as a stationary phase for a micro gas chromatography column (μGCC) fabricated using micro-electro-mechanical system (MEMS) technology. The separation results showed that the μGCC with the FG-HKUST-1 composite stationary phase achieved a baseline separation of C 1 -C 4 in 8 min. The retention factors for C 2 -C 4 were 2.13, 7.14, and 12.04, respectively. The maximum relative standard deviation (RSD) of the retention times was 0.14 %. The difference in the retention time between methane and ethane was 1.11 min, with a resolution of 9.2 for methane and ethane. The retention factor of ethane and the resolution of methane and ethane were increased by 166 % and 114 %. Therefore, this μGCC is promising for separating light hydrocarbons with widely differing concentrations.
In this work, tris(oxiran-2-ylmethyl) benzene-1,3,5-tricarboxylate (TOTC) was synthesized by a new two-step method without using harmful epichlorohydrin and served as a curing agent for polyester powder coatings. The chemical structure of TOTC was determined by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The curing behavior and the curing reaction kinetics of TOTC/polyester resin (NH-3307) system were studied by dynamic differential scanning calorimetry. The activation energy E a was 71.75 kJ mol -1 according to Flynn–Wall–Ozawa method, and the curing reaction of TOTC/NH-3307 system was described by Friedman method. It was found that the curing reaction of TOTC/NH-3307 system was a two-parameter autocatalysis which followed the Šestάk–Berggren model. The nonisothermal curing reaction rate was simulated according to the Šestάk–Berggren model and the experimentally parameters. What is more, the thermogravimetric analysis results showed that the TOTC/NH-3307 system had good thermal stability with an initial decomposition temperature of 374.92°C. The TOTC/NH-3307 cured film exhibited excellent leveling performance by SEM. The results demonstrated that TOTC has efficient curing ability and huge market potential.
Long Tian,Xiaonan Song,Yi Liu,Churu Zhang,Lan Shi,Qinglin Chen,Yanyan Deng,Weigang Cui,Shaoyun Shan,Tianding Hu
Defect-engineered metal–organic frameworks (DEMOFs) are emerging advanced materials. The construction of DEMOFs is of great significance; however, DEMOF-based catalysis remains unexplored. (E)-vinylboronates, an important building block for asymmetric synthesis, can be synthesized via the hydroboration of alkynes. However, the lack of high-performance catalysts considerably hinders their synthesis. Herein, a series of DEHKUST-1 (HKUST = Hong Kong University of Science and Technology) (Da–f) catalysts with missing occupation of linkers at Cu nodes were designed by partially replacing benzene-1,3,5-tricarboxylate (H 3 BTC) with defective connectors of pyridine-3,5-dicarboxylate (PYDC) to efficiently promote the hydroboration of alkynes. Results showed that the Dd containing 0.8 doping ratio of PYDC exhibited remarkable catalytic activity than the defect-free HKUST-1. This originated from the improved accessibility for reactants towards the Lewis acid active Cu sites of DEHKUST-1 due to the presence of plenty of rooms next to the Cu sites and enhanced coordination ability in such ‘defective’ HKUST-1. Dd had high selectivity (>99 %) and yield (>96 %) for (E)-vinylboronates and extensive functional group compatibility for terminal alkynes. Density functional theory (DFT) calculations were performed to elucidate the mechanism of hydroboration. Compared with that of defect-free HKUST-1, the low energy barrier of DEHKUST-1 can be attributed to the lower coordination number of Cu sites and enhanced accessibility of Cu active sites towards reagents.
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