摘要: Xianfeng lignite (XL) was firstly thermal dissolved in the isometric toluene/methanol mixed solvent at 300℃ in a stainless-steel autoclave to afford a soluble portion (SPXL) and a residue (RXL), then the nitrogen forms in XL and RXL were characterized with X-ray photoelectron spectroscopy (XPS) analysis, and the nitrogen-containing species (NCSs) in SPXL were identified using gas chromatography/mass spectrometry (GC/MS) and electrospray ionization Fourier transform ion cyclotron mass spectrometry (ESI FT-ICR MS) analyses. The results show that the amount of nitrogen forms in XL is in the order of quaternary-N>pyridinic-N>pyrrolic-N, while quaternary-N in XL is easily dissolved out during thermal dissolution. In total 20 NCSs were detected in SPXL by GC/MS, and most of them are amines. Over three hundreds of NCSs were identified in SPXL by ESI FT-ICR MS, and most of them are the NCSs containing one or three nitrogen atoms. The NCSs containing one nitrogen atom are mainly dominated by N1O1, N1O2 and N1OxS1-2 class species, while most of NCSs containing three nitrogen atoms are N3OxS1-2 class species (x=1-12). The double bond equivalent (DBE) values and carbon number of the NCSs containing one nitrogen atom increase with increasing number of oxygen atoms.
摘要: In this research, a solid 1%Li/Ca-La mixed oxide catalyst was prepared using co-precipitation method followed by wet impregnation. The prepared catalyst was used in the transesterification reaction of canola oil and methanol for biodiesel synthesis. The effects of calcination and reaction temperatures were investigated on the activity of the catalyst. In addition, rate of the reaction was studied through a kinetic model for which parameters were determined. Surface properties and structure of the catalyst were characterized through the powder X-ray diffraction (XRD), thermogravimetry/derivative thermogravimetry (TG/DTG), and Fourier transform infrared spectroscopy analysis. All these emphasized that the performance of the catalyst corresponded to the generation of the active sites and their thermal activation.
摘要: Pd and Pd-Ag nanoparticles supported on multi-walled carbon nanotubes (MWCNT) were prepared by using the NaBH4 reduction method in a mixed solvent of ethylene glycol and water; their catalytic activity for the electro-oxidation of ethanol, n-propanol and iso-propanol was investigated in alkaline media by the voltammetric method. The results indicate that Pd and Pd-Ag nanoparticles are well-dispersed on the surface of MWCNTs and the average sizes of metal particles on the Pd/MWCNT, Pd4Ag1/MWCNT, Pd2Ag1/MWCNT and Pd1Ag1/MWCNT catalysts are 7, 4, 7 and 11 nm, respectively. Over these catalysts, the electro-oxidation of n-propanol exhibits larger current density than the oxidation of ethanol and iso-propanol. Moreover, the binary PdnAg1/MWCNT catalysts (n=4, 2, 1), especially Pd4Ag1/MWCNT, gives higher current density for the oxidation of ethanol and propanols than the Pd/MWCNT catalyst, suggesting that the addition of Ag can enhance the activity of Pd-based catalyst for the electro-oxidation of alcohols. The excellent activity of binary Pd-Ag/MWCNT catalysts is probably attributed to the weak absorption of intermediate species on Pd due to the interaction between Pd and Ag, which may promote the oxidation of alcohols.