Co-reporter:Dan Yang, Dan Li, Haoyu Yao, Guoliang Zhang, Tiantian Jiao, Zengxi Li, Chunshan Li, and Suojiang Zhang
Industrial & Engineering Chemistry Research 2015 Volume 54(Issue 27) pp:6865-6873
Publication Date(Web):June 17, 2015
DOI:10.1021/acs.iecr.5b01422
A new route to synthesizing acrylic acid from acetic acid and formalin by one-step aldol condensation reaction was proposed and developed. V–P/SiO2 oxide bifunctional catalysts were designed and prepared by ultrasonic impregnation method. The catalysts were characterized by XRD, BET, TEM, TG/DTA, and XPS, as well as NH3- and CO2-TPD and pyridine-FTIR methods. Catalytic performance was evaluated using a fixed-bed tubular microreactor operating with a CH3COOH/HCHO (HAc/FA) molar ratio of 10 under atmospheric pressure. Influences of the balance between acidic and alkaline sites, as well as ratio of V4+ and V5+, on catalyst activity were further studied. Reaction parameters were systemically optimized. Through a series of comparisons, V–P/SiO2 binary oxide catalyst with a bulk density ratio of 1:2 was selected.
Co-reporter:Wenjun Hao, Shimou Chen, Yingjun Cai, Lan Zhang, Zengxi Li and Suojiang Zhang
Journal of Materials Chemistry A 2014 vol. 2(Issue 34) pp:13801-13804
Publication Date(Web):30 May 2014
DOI:10.1039/C4TA02012J
Three-dimensional hierarchical pompon-like Co3O4 porous spheres were synthesized by a hydrothermal method. It was found that the crystal-splitting mechanism plays a key role in the formation of these pompon-like structures. When tested as anode materials in lithium ion batteries (LIBs), they showed higher specific capacity and better cycle performance than those of Co3O4 nanoparticles and nanowires.
Co-reporter:Bin Li, Ruiyi Yan, Lei Wang, Yanyan Diao, Zengxi Li, and Suojiang Zhang
Industrial & Engineering Chemistry Research 2014 Volume 53(Issue 4) pp:1386-1394
Publication Date(Web):January 6, 2014
DOI:10.1021/ie403422s
SBA-15 supported metal-doped cesium ion catalysts were prepared by the impregnation method and characterized by N2 adsorption–desorption, XRD, FT-IR, and SEM and TEM. The characterization results indicated that the ordered hexagonal mesoporous structure of the support remained intact after incorporating cesium. Stepwise TPD of NH3 and CO2 was used to estimate the strength and the number of surface acid and base sites, respectively. The effects of Cs-loading, sources of cesium cation, and template concentration on the physicochemical properties and catalytic performance were investigated. The catalytic performance was evaluated by the gas-phase condensation reaction of methyl propionate with formaldehyde in a fixed-bed reactor. Compared with the amorphous SiO2 catalyst, at similar Cs loading (ca. 15 wt %) SBA-15 catalyst exhibited better selectivity and yield.
Co-reporter:Tao Zhang, Long Liu, Chunshan Li, Yanqiang Zhang, Zengxi Li, Suojiang Zhang
Journal of Molecular Structure 2014 1067() pp: 195-204
Publication Date(Web):5 June 2014
DOI:10.1016/j.molstruc.2014.03.029
•Propan-2-ylidene methanetriamium is the new structures.•Bond homogenization of the salts suggests delocalization of the charge.•The salts are hypergolic with white fuming nitric acid.Development of new hypergolic ionic liquids is the key in replacing toxic N,N-dimethylhydrazine as green liquids propellants. Three salts based on the new propan-2-ylidene methanetriamium cations and dicyanamide anion were synthesized and characterized by 1H and 13C NMR, IR and Raman spectroscopy, elemental analysis, and TG/DTA. In addition, their crystal structures were determined by X-ray single crystal diffraction. N-(propan-2-ylidene) methanetriamium dicyanamide (1) crystallizes in the monoclinic space group P21/n, N,N′-bi(propan-2-ylidene) methanetriamium dicyanamide (2) in triclinic P − 1, and N,N′,N″-tri(propan-2-ylidene) methanetriamium dicyanamide (3) in monoclinic C2/c. With heats of formation (from 1.56 to 1.80 kJ g−1) and densities (from 1.19 to 1.31 g cm−3) in hand, the detonation pressure (P) and velocity (D), and specific impulse (Isp) values of salts were calculated as 8.94 GPa, 4989 m s−1 and 174.3 s (1), 7.91 GPa, 4815 m s−1 and 179.0 s (2), and 7.33 GPa, 4693 m s−1 and 180.6 s (3), respectively. Impact sensitivities of 1, 2 and 3 were measured to be no less than 40 J by hammer tests, which places these salts in the insensitive class. Moreover, the resulting salts are hypergolic with white fuming nitric acid and exhibit potential as bipropellants.
Co-reporter:L. Jiang;C. Li;Z. Li;S. Zhang
Chemical Engineering & Technology 2013 Volume 36( Issue 11) pp:1891-1898
Publication Date(Web):
DOI:10.1002/ceat.201300425
Abstract
A series of CuO/Ce0.6Zr0.4O2 catalysts doped with rare earth (Y, La) oxides and transition metal (Fe, Co, Ni) promoters were synthesized by the coprecipitation method. The effects of the additive type and content on the structure, redox properties, and water-gas shift (WGS) catalytic activity were investigated in detail by X-ray diffraction, N2 physisorption, scanning electron microscopy, energy-dispersive X-ray spectroscopy, H2 temperature-programmed reduction, and Raman spectroscopy. The catalytic activity was tested in terms of CO in H2-rich coal-derived synthesis gas, which simulated the actual gas composition of an integrated gasification combined cycle system. The experimental results revealed the beneficial role of doping with 3 wt % Fe in enhancing the catalytic performance by increasing the oxygen storage and mobility capacity, the reducibility, and the synergistic interaction between copper oxide and ceria-zirconia.
Co-reporter:Bin Li;Ruiyi Yan;Lei Wang;Yanyan Diao;Suojiang Zhang
Catalysis Letters 2013 Volume 143( Issue 8) pp:829-838
Publication Date(Web):2013 August
DOI:10.1007/s10562-013-1040-4
Supported cesium catalysts with various carriers (SiO2, Al2O3, TiO2, MgO) were prepared and characterized by X-ray diffraction, BET nitrogen adsorption–desorption, NH3 and CO2-TPD methods and thermogravimetric analysis. Experimental results showed that the Zr–Mg–Cs/SiO2 catalyst exhibited moderate activity for aldol condensation of methyl propionate with formaldehyde (FA) to produce methyl methacrylate. Though the activity of Zr–Mg–Cs/SiO2 catalyst decreased with the time-on-stream, the deactivated catalyst was completely regenerated by calcination. The catalyst was regenerated 16 times and total operation time was over 500 h, its activity was identical with that of the fresh catalyst.
Co-reporter:Li Jiang, Hongwei Zhu, Rauf Razzaq, Minlin Zhu, Chunshan Li, Zengxi Li
International Journal of Hydrogen Energy 2012 Volume 37(Issue 21) pp:15914-15924
Publication Date(Web):November 2012
DOI:10.1016/j.ijhydene.2012.08.055
A series of CexZr1−xO2-based Cu catalysts was synthesized by the co-precipitation method. The influences of copper content, zirconium addition, and ratio of ceria to zirconia on the catalytic activity were investigated. BET, N2O decomposition, XRD, TEM, SEM, EDS, Raman spectroscopy, H2-TPR, TG/DTA, and XPS were used to characterize the catalysts. The catalytic activity was tested in terms of CO conversion and H2 selectivity in H2-rich coal-derived synthesis gas, simulating the actual gas composition of an integrated gasification combined cycle (IGCC) system. The long-term catalyst stability was also examined at 450 °C for 196 h. The addition of zirconium was found to be very important in enhancing catalytic performance. The surface area, copper dispersion, oxygen storage and mobility capacity, reducibility, as well as resistance to sintering all improved after zirconium addition.Highlights► Microporous CuO/CexZr1−xO2 catalyst was synthesized by co-precipitation method. ► Zirconium doping can raise oxygen storage capacity and reducibility of catalyst. ► Zirconium addition can enhance catalytic stability of CuO/CeO2 catalyst.
Co-reporter:Long Liu, Yong Jian, Zengxi Li, Chunshan Li
Thermochimica Acta 2012 Volume 541() pp:25-30
Publication Date(Web):10 August 2012
DOI:10.1016/j.tca.2012.04.023
This paper describes the synthesis and thermal behavior of 1,7-diamino-1,7-dinitrimino-2,4,6-trinitro-2,4,6-triazaheptane (APX). The non-isothermal kinetics of APX was calculated by using the differential isoconversional method based on thermo-gravimetric/differential thermal analyzer results. It was found that with the extent of conversion increase, the activation energy increase from 136.6 kJ/mol to the highest value of 294.0 kJ/mol at the conversion of 40%, and then decrease to 248.2 kJ/mol; In addition, the decomposition mechanism of APX was systematically studied by in situ pyrolytic Fourier transform infrared spectroscopy, electron impact ionization analysis and density functional theory. The final decomposition products of APX were conformed to include N2O, NO2, CONH, H2CO, etc. The lowest bond dissociation energy of APX is NN bonds and these may be decomposed initially. Finally, the most probable decomposition pathway based on the N6N7 bond homolysis was proposed and the theoretical results are in good agreement with experimental data.Highlights► The non-isothermal kinetics of APX was calculated by using the differential isoconversional method. ► The final decomposition products of APX were confirmed to include N2O, NO2, CONH, and H2CO. ► The decomposition mechanisms of APX were proposed by in situ pyrolytic FT-IR, MS and DFT calculations.
Co-reporter:Long Liu;Chunlin He;Chunshan Li
Journal of Chemical Crystallography 2012 Volume 42( Issue 8) pp:816-823
Publication Date(Web):2012 August
DOI:10.1007/s10870-012-0319-4
New nitrogen-rich energetic compound 5-amino-1-nitriminotetrazole (2) and its ammonium (3), hydrazinium (4) salts have been prepared. Their structures were characterized and confirmed by 1H NMR spectroscopy, IR spectroscopy, elemental analysis and ESI-MS, X-ray single-crystal diffraction. Compound 2 crystallizes in the orthorhombic Pna2(1) space group with unit cell parameters are a = 9.229(2) Å, b = 5.5271(13) Å, c = 10.295(2) Å, V = 525.1(2) Å3, Z = 4. Compound 3 crystallizes in the Monoclinic C2/c space group, its unit cell parameters are a = 25.932 (6) Å, b = 6.8844(15) Å, c = 14.006(3) Å, β = 102.052(3), V = 2445.3(10) Å3, Z = 16. Compound 4 crystallizes in the Monoclinic P2(1)/c space group with unit cell parameters are a = 7.275(3) Å, b = 14.273(5) Å, c = 6.802(2) Å, β = 97.009(5) Å, V = 701.0(4) Å3, Z = 4. Extensive hydrogen bonds of these compounds packed a 3D network. Finally, the influences of molecular structure on the properties of the new compounds were discussed.
Co-reporter:Zhen Liu, Hui Wang, Zengxi Li, Xingmei Lu, Xiangping Zhang, Suojiang Zhang, Kebin Zhou
Materials Chemistry and Physics 2011 Volume 128(1–2) pp:220-227
Publication Date(Web):15 July 2011
DOI:10.1016/j.matchemphys.2011.02.062
Dissolution and regeneration of cotton pulp using ionic liquids as solvent was investigated. The physicochemical properties of the regenerated cellulose films have been characterized by scanning electron microscopy, X-ray diffractometer, infrared spectrometric analyzer, differential scanning calorimeter, and thermogravimetric analysis instrument. The rheological properties of cotton pulp dissolved in ionic liquids have been investigated by steady shear and oscillatory shear measurements. The influences of experimental parameters, such as the reaction temperature, additives on the solubility and degree of polymerization (DP) of regenerated cellulose were also studied. The results show that 1-butyl-3-methylimidazolium chloride ([bmim]Cl) was a good solvent to dissolve cotton pulp and the solubility can reach 13 wt% at 90 °C, but the DP remarkably decreased from 510 to 180 within 7 h. It was found that additive N-methylimidazole can effectively minimize DP loss of the regenerated cellulose, which can attribute to the fact that in the mixture of [bmim]Cl and NMI solution, the β-1,4-glycosidic bond of the cellulose chains cannot be broken because of the relative low concentration of Cl−. In the steady shear measurement, all the solutions show a shear thinning behavior at high shear rates. In addition, a mechanism of the dissolution of cellulose in [bmim]Cl was proposed.Highlights► The solubility can reach 13 wt% at 90 ̊C in ionic liquid of [bmim]Cl. ► Additive N-methylimidazole can minimize DP loss of the regenerated films. ► A mechanism of the dissolution of cellulose in [bmim]Cl was proposed. ► The ionic liquid of [bmim]Cl could be recycled.
Co-reporter:Long Liu, Chunlin He, Hui Wang, Zengxi Li, Song Chang, Jian Sun, Xiangping Zhang, Suojiang Zhang
Journal of Molecular Structure 2011 Volume 989(1–3) pp:136-143
Publication Date(Web):15 March 2011
DOI:10.1016/j.molstruc.2010.12.052
A series of organic salts based on ethylenediaminium divalent cation, [C2H10N2]X2 (where X = 2-nitrophenolate (1), 3-nitrophenolate (2), 4-nitrophenolate (3), 2,4-dinitrophenolate (4), 2,6-dinitrophenolate (5) and 2,4,6-trinitrophenolate (6) respectively) have been prepared. Their structures were characterized and confirmed by 1H and 13C NMR spectroscopy, IR spectroscopy, elemental analysis and ESI-MS. Additionally, crystal structures of compounds 2-nitrophenolate and 4-nitrophenolate were determined with X-ray single crystal diffraction. Complex salt 1 crystallizes in the orthorhombic Pccn space group with unit cell parameters: a = 26.047(5) Å, b = 6.8351(14) Å, c = 8.4637(17) Å, V = 1506.8 Å3, Z = 4. Complex salt 3 crystallizes in the monoclinic C2/c space group with additional one free water molecule being included. Its unit cell parameters are a = 11.328(2) Å, b = 7.2623(15) Å, c = 20.038(4) Å, β = 93.58(3)°, V = 1615.2(6) Å3, Z = 4. Compounds 1 and 3 have strong 3D hydrogen-bonded network, which play a major role in stabilizing the crystal lattice. Distinct cationic and anionic layers can also be seen in the (0 1 0) plane. The IR and Raman spectra of 2-nitrophenolate and 4-nitrophenolate were interpreted and the assignments of bands to the corresponding vibrations were proposed based on the data calculated by the B3LYP/6-311G(d, p) level. Finally, the influence of molecular structure on both the densities and thermal stabilities of synthesized compounds have been discussed.
Co-reporter:Zhen Liu;Hui Wang;Xingmei Lu;Xiangping Zhang;Suojiang Zhang;Kebin Zhou
Polymer Engineering & Science 2011 Volume 51( Issue 12) pp:2381-2386
Publication Date(Web):
DOI:10.1002/pen.22010
Abstract
Rheological properties of cotton pulp dissolved in 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) solutions were characterized using an advanced rheometer. The complex viscosity, dynamic modulus, and shear viscosity at different temperature were studied. In the steady shear measurements, all the solutions show a shear-thinning behavior at high shear rates. The complex viscosity as a function of frequency was fitted by extended Carreau–Yasuda model. In all cotton pulp/[Bmim]Cl solutions, the complex dynamic viscosity (η*) and steady shear viscosity (ηa) followed the Cox–Merz rule only at lower frequency. The effects of tested temperature on viscosity and viscoelastic behavior of the solutions were also investigated. The value of activation energy for the dissolution of cotton pulp in ionic liquids was 65.28 kJ/mol at the concentration of 10 wt% and was comparable with the ones for the dissolution of cellulose in NMMO. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Co-reporter:Qian Wang;Lei Wang;Hui Wang
Frontiers of Chemical Science and Engineering 2011 Volume 5( Issue 1) pp:79-88
Publication Date(Web):2011 March
DOI:10.1007/s11705-010-0550-6
A series of SAPO-34 molecular sieves with different SiO2/Al2O3 ratios have been synthesized for the methanol-to-olefin (MTO) reaction. Their physico-chemical properties are characterized by various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR) and N2 adsorption- desorption. The results are compared with those of the commercial HZSM-5, which show that the crystallinity and particle diameter of SAPO-34 as well as HZSM-5 increase with SiO2/Al2O3 ratio. The variation of BET surface area of SAPO-34 is different from that of HZSM-5 and the sample with SiO2/Al2O3 ratio of 0.4 exhibits the highest BET surface area. FT-IR spectra indicate that HZSM-5 has both Br.nsted and Lewis acid sites and Bronsted acid sites are stronger, whereas SAPO-34 samples are dominated only by Lewis acid sites. When the SiO2/Al2O3 ratio increases, propylene and butylenes become the predominant product of the MTO reaction over HZSM-5. In contrast, the main products of this reaction catalyzed by SAPO-34 are ethylene and propylene. According to the product distribution, the reaction mechanism over HZSM-5 catalysts is proposed.
Co-reporter:Hui Wang, Yanqing Liu, Zengxi Li, Xiangping Zhang, Suojiang Zhang, Yanqiang Zhang
European Polymer Journal 2009 Volume 45(Issue 5) pp:1535-1544
Publication Date(Web):May 2009
DOI:10.1016/j.eurpolymj.2009.01.025
Poly(ethylene terephthalate) (PET) from an industrial manufacturer was depolymerized by ethylene glycol in the presence of a novel catalyst: ionic liquids. It was found that the purification process of the products in the glycolysis catalyzed by ionic liquids was simpler than that catalyzed by traditional compounds, such as metal acetate. Qualitative analysis showed that the main product in the glycolysis process was the bis(hydroxyethyl) terephthalate (BHET) monomer. Thermal analysis of the glycolysis products was carried out by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The influences of experimental parameters, such as the amount of catalyst, glycolysis time, reaction temperature, and water content in the catalyst on the conversion of PET, selectivity of BHET, and distribution of the products were investigated. Results show that reaction temperature is a critical factor in this process. In addition, a detailed reaction mechanism of the glycolysis of PET was proposed.
Co-reporter:Wenjun Hao, Shimou Chen, Yingjun Cai, Lan Zhang, Zengxi Li and Suojiang Zhang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 34) pp:NaN13804-13804
Publication Date(Web):2014/05/30
DOI:10.1039/C4TA02012J
Three-dimensional hierarchical pompon-like Co3O4 porous spheres were synthesized by a hydrothermal method. It was found that the crystal-splitting mechanism plays a key role in the formation of these pompon-like structures. When tested as anode materials in lithium ion batteries (LIBs), they showed higher specific capacity and better cycle performance than those of Co3O4 nanoparticles and nanowires.
