Co-reporter:Xiufang Wang, Shujie Wu, Zhifang Li, Xiaoyuan Yang, Hailiang Su, Jing Hu, Qisheng Huo, Jingqi Guan, Qiubin Kan
Microporous and Mesoporous Materials 2016 Volume 221() pp:58-66
Publication Date(Web):February 2016
DOI:10.1016/j.micromeso.2015.09.020
•Cu(II), Co(II), Fe(III) or VO(II) Schiff base complexes were covalently attached on amino-modified CMK-3-O.•The catalysts were characterized by XRD, FT-IR, SEM, TEM, TG, Raman, BET, XPS and ICP-AES.•The catalysts were active and showed good recoverability in the epoxidation of styrene.Schiff base complexes containing transition metals (Cu, Co, Fe or V) were successfully immobilized onto amino-functionalized CMK-3 via a stepwise procedure as heterogeneous catalysts for styrene epoxidation. The materials were characterized by means of XRD, N2 adsorption/desorption, TEM, SEM, FT-IR, Raman, XPS, TG. and ICP-AES. The results of XRD, N2 adsorption–desorption and TEM revealed that the structure of CMK-3 was well preserved, while the results of FT-IR, TG, Raman, XPS and ICP-AES suggested that the Cu(II), Co(II), Fe(III) or VO(II) Schiff base complexes have been successfully incorporated onto amino-modified CMK-3. Catalytic results showed that high conversion of styrene (94.1%) and selectivity to styrene oxide (73.9%) can be achieved over the heterogeneous Co (II) catalyst with air as the oxidant and isobutyraldehyde as co-reductant. In addition, the functionalized CMK-3 catalyst was quite stable and could be recycled at least three times.
Co-reporter:Xiufang Wang;Shujie Wu;Zhifang Li;Xiaoyuan Yang;Jing Hu;Qisheng Huo;Jingqi Guan
Applied Organometallic Chemistry 2015 Volume 29( Issue 10) pp:698-706
Publication Date(Web):
DOI:10.1002/aoc.3353
Oxovanadium(IV), copper(II) and cobalt(II) acetylacetone complexes have been grafted onto amino-modified CMK-3-O (VO-NH2-CMK-3, Cu-NH2-CMK-3 and Co-NH2-CMK-3,respectively) and the materials thus prepared were used as heterogeneous catalysts for the aerobic oxidation of styrene. X-ray diffraction, nitrogen adsorption–desorption and transmission electron microscopy measurements confirmed the structural integrity of the mesoporous hosts, and spectroscopic characterization techniques (Fourier transform infrared, X-ray photoelectron, Raman) and thermogravimetry confirmed the ligands and the successful anchoring of the acetylacetone complexes to the modified mesoporous support. VO-NH2-CMK-3 displayed a relatively good catalytic performance with 94.6% of styrene conversion using air as oxidant, while Cu-NH2-CMK-3 gave 99.6% of styrene conversion using tert-butyl hydroperoxide as oxidant. Copyright © 2015 John Wiley & Sons, Ltd.
Co-reporter:Jing Hu;Shujie Wu;Zhifang Li;Ling Peng;Xiaoran Fu;Xiufang Wang;Jingqi Guan
Applied Organometallic Chemistry 2015 Volume 29( Issue 9) pp:638-645
Publication Date(Web):
DOI:10.1002/aoc.3345
The work reported was aimed at a simple method to improve the catalytic activity of Mo/HMCM-22 in methane aromatization. The catalysts were characterized using X-ray diffraction, scanning electron microscopy, N2 adsorption–desorption, NH3 temperature-programmed desorption, infrared spectra of pyridine adsorption, X-ray photoelectron spectroscopy and thermogravimetric analysis. Physicochemical measurements indicated that Mo species with smaller size in HMCM-22 would sublimate more easily and form Mo species at the atomic/molecular level and then interact well with the internal Brønsted acid sites to form Mo–O–Al active species. Catalytic results confirmed that nano-MoO3-modified HMCM-22 showed higher methane conversion and aromatics yield (13.1 versus 8.9%) than commercial MoO3-modified HMCM-22 (11.0 versus 7.5%). In addition, nano-MoO3-modified HMCM-22 showed better durability compared with commercial MoO3-modified MCM-22. Copyright © 2015 John Wiley & Sons, Ltd.
Co-reporter:Hailiang Su;Shujie Wu;Zhifang Li;Qisheng Huo;Jingqi Guan
Applied Organometallic Chemistry 2015 Volume 29( Issue 7) pp:462-467
Publication Date(Web):
DOI:10.1002/aoc.3316
Cobalt(II), iron(III) or oxovanadium(II) Schiff base metal complexes have been covalently grafted onto graphene oxide (GO) previously functionalized with 3-aminopropyltriethoxysilane. Potential catalytic behaviors were tested in the epoxidation of styrene, using air as the oxidant. The catalysts were characterized using infrared (IR) and Raman spectroscopies, thermogravimetric analyses, inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray diffraction, nitrogen adsorption–desorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). IR spectroscopy, thermogravimetric analyses and ICP-AES confirmed the successful incorporation of the metal Schiff base complexes onto GO. X-ray diffraction, nitrogen adsorption–desorption, Raman spectroscopy, SEM and TEM showed the intact structure of the GO. Co-GO and Fe-GO showed high styrene conversion (90.8 versus 86.7%) and epoxide selectivity (63.7 versus 51.4%). Nevertheless, VO-GO showed poorer catalytic performance compared with Co-GO and Fe-GO. The recycling results of these heterogeneous catalysts showed good recoverability without significant loss of activity and selectivity within four successive runs. Copyright © 2015 John Wiley & Sons, Ltd.
Co-reporter:Jing Hu, Shujie Wu, Heng Liu, Hong Ding, Zhifang Li, Jingqi Guan and Qiubin Kan
RSC Advances 2014 vol. 4(Issue 51) pp:26577-26584
Publication Date(Web):20 Jun 2014
DOI:10.1039/C4RA03945A
A series of micro-mesoporous molecular sieves TNU-9-x (TNU-9 Taejon National University no. 9) were prepared by a hydrothermal reaction method for non-oxidative aromatization of methane. The physical properties of the synthesized samples were characterized by XRD, SEM, TEM, BET, NH3-TPD and FT-IR spectroscopy. Characterization results suggested that the micro-mesoporous molecular sieves TNU-9-x exhibited similar geometrical shapes, but different pore properties with conventional microporous molecular sieve TNU-9. Catalytic tests indicated that Mo–TNU-9-20 showed excellent catalytic performance with a 14.9% conversion of methane and a 9.9% yield of aromatics. In addition, the catalytic stability of Mo–TNU-9-20 was better than the conventional microporous material Mo–TNU-9. The improved catalytic behaviour might be attributed to the generation of a secondary mesoporous system within the hierarchical pore materials.
Co-reporter:Hailiang Su, Zhifang Li, Qisheng Huo, Jingqi Guan and Qiubin Kan
RSC Advances 2014 vol. 4(Issue 20) pp:9990-9996
Publication Date(Web):31 Jan 2014
DOI:10.1039/C3RA47732K
Transition metal (Fe2+, Co2+, VO2+ or Cu2+) Schiff base complexes were immobilized onto graphene oxide previously functionalized with 3-aminopropyltriethoxysilane (3-APTES). X-ray diffraction (XRD), IR spectroscopy, thermal gravimetric analyses (TGA) and inductively coupled plasma atomic emission spectroscopy (ICP-AES) confirmed the successful incorporation of the metal Schiff base onto the graphene oxide. N2 adsorption–desorption, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed the intact structure of the graphene oxide. Catalytic results showed that the immobilized copper(II) Schiff base complex catalyst was more active than the immobilized iron(II), cobalt(II) and oxovanadium(IV) complexes in the epooxidation of styrene. Above 94% styrene conversion and excellent ∼99% selectivity to the epoxide could be achieved over the copper(II) Schiff base heterogeneous catalyst in the epoxidation of styrene using tert-butyl hydroperoxide (TBHP) as oxidant after 7 h reaction. The recycling experiment results indicated that the catalyst could maintain very high styrene conversion (>93%) and epoxide selectivity (>99%) even after being used for four cycles.
Co-reporter:Zhifang Li;Shujie Wu;Dafang Zheng;Jiayin Liu;Heng Liu;Haiming Lu;Qisheng Huo;Jingqi Guan
Applied Organometallic Chemistry 2014 Volume 28( Issue 5) pp:317-323
Publication Date(Web):
DOI:10.1002/aoc.3127
Transition metal salen complex MoO2–salen was successfully tethered onto amino-functionalized graphene oxide (designated as MoO2–salen–GO), which was tested in the epoxidation of various alkenes using tert-butylhydroperoxide or H2O2 as oxidant. Characterization results showed that dioxomolybdenum(VI) complex was successfully grafted onto the amino-functionalized graphene oxide and the structure of the graphene oxide was well preserved after several stepwise synthesis procedures. Catalytic tests showed that heterogeneous catalyst MoO2–salen–GO was more active than its homogeneous analogue MoO2–salen in the epoxidation of cyclooctene due to site isolation. In addition, the MoO2–salen–GO catalyst could be reused three times without significant loss of activity. Copyright © 2014 John Wiley & Sons, Ltd.
Co-reporter:Dr. Zhifang Li;Shujie Wu;Dafang Zheng;Hong Ding;Xiufang Wang;Xiaoyuan Yang; Qisheng Huo; Jingqi Guan; Qiubin Kan
ChemPlusChem 2014 Volume 79( Issue 5) pp:716-724
Publication Date(Web):
DOI:10.1002/cplu.201300424
Abstract
Core–shell structural magnetic nanocatalysts, involving carbon-coated magnetic Fe3O4 nanoparticles supported on graphene oxide sheets (mildly reduced graphene oxide (MRGO)/Fe3O4@C) and carbonaceous coatings on magnetic Fe3O4 nanoparticles (Fe3O4@C), for immobilizing metal (CuII, CoII, FeIII or VOIV)–salen complexes were prepared by a facile, green, and efficient chemical approach and first applied in the aerobic epoxidation of styrene with air as the oxidizing agent. The prepared catalysts were characterized by different techniques, such as XRD, TEM, FTIR spectroscopy, inductively coupled plasma atomic emission spectroscopy, TEM, thermogravimetric analysis, Raman spectroscopy, and X-ray photoelectron spectroscopy. The magnetic nanocatalysts MRGO/Fe3O4@C–salen–M (M=Cu, Co, Fe, or V) exhibited higher catalytic reactivity than that of the corresponding Fe3O4@C–salen–M (M=Cu, Co, Fe, or V) species possibly owing to site isolation, good dispersion of magnetic Fe3O4 nanoparticles, and an efficiently synergistic effect between the metal complexes and the supports. Furthermore, MRGO/Fe3O4@C–salen–Co exhibited up to 92.3 % conversion of styrene and 59.2 % selectivity to the styrene oxide upon using air as the oxidizing agent and showed good recoverability with negligible loss in activity and selectivity within successive runs owing to superparamagnetism. Most importantly, these materials can be easily recovered by simple magnetic separation.
Co-reporter:Zhifang Li, Shujie Wu, Hong Ding, Haiming Lu, Jiayin Liu, Qisheng Huo, Jingqi Guan and Qiubin Kan
New Journal of Chemistry 2013 vol. 37(Issue 12) pp:4220-4229
Publication Date(Web):16 Oct 2013
DOI:10.1039/C3NJ00982C
Oxovanadium(IV) and iron(III) salen complexes grafted onto amino-modified graphene oxide (NH2–GO) have been synthesized via a stepwise procedure and the prepared materials were used as heterogeneous catalysts in the aerobic oxidation of styrene. The structures of these materials have been thoroughly investigated using different characterization techniques such as XRD, N2 adsorption–desorption, TEM, FT-IR, diffuse reflectance UV-visible spectroscopy, ICP-AES, TEM, TG, Raman, and XPS. The results of XRD, N2 adsorption–desorption and TEM revealed that the structures of the prepared catalysts were well preserved. In addition, the results of FT-IR, diffuse reflectance UV-visible spectroscopy, ICP-AES, TG, Raman and XPS suggested that the oxovanadium(IV) and iron(III) complexes had been incorporated onto amino-modified graphene oxide (GO). It was found that the heterogeneous oxovanadium(IV) catalyst was more active than its homogeneous analogue in the epoxidation of styrene, using acetonitrile as solvent and air as the oxidant in combination with the sacrificial co-reductant isobutyraldehyde, due to site-isolation. Furthermore, the tethered vanadium catalyst was quite stable and could be recycled many times.
Co-reporter:Zhifang Li, Shujie Wu, Hong Ding, Dafang Zheng, Jing Hu, Xu Wang, Qisheng Huo, Jingqi Guan and Qiubin Kan
New Journal of Chemistry 2013 vol. 37(Issue 5) pp:1561-1568
Publication Date(Web):05 Mar 2013
DOI:10.1039/C3NJ00099K
Novel graphene oxide (GO) tethered Cu(II) and Co(II) salen complexes [M–Salen–GO (M = Cu, Co)] were synthesized via a stepwise procedure and examined as catalysts in the epoxidation of styrene. Acetonitrile was used as a solvent and air as the oxidant in combination with a sacrificial co-reductant isobutyraldehyde. A comparison with homogeneous salen complexes of Co and Cu and graphene oxide (GO) tethered salen complexes was made. Heterogeneous copper(II) and cobalt(II) catalysts were confirmed by X-ray diffraction (XRD), FT-IR, diffusion reflection UV-visible spectroscopy, inductively coupled plasma atomic emission spectroscopy (ICP-AES), TEM, TG, Raman and XPS. FT-IR, diffusion reflection UV-visible and inductively coupled plasma atomic emission spectroscopy (ICP-AES), along with TG, Raman and XPS results showed that Cu(II) and Co(II) salen complexes were successfully grafted on GO; X-ray diffraction (XRD) and TEM indicated that the sample structures were well preserved. It was found that heterogeneous catalysts were active and showed good recoverability without significant loss in activity and selectivity within successive runs.
Co-reporter:Heng Liu;Jing Hu;Zhifang Li;Shujie Wu;Lulu Liu;Jingqi Guan
Kinetics and Catalysis 2013 Volume 54( Issue 4) pp:443-450
Publication Date(Web):2013 July
DOI:10.1134/S0023158413040083
The hydrothermal crystallization of zeolite IM-5 was investigated under rotating (denoted as IM-5-R) and static (denoted as IM-5-S) synthesis conditions. Mo-modified catalysts (Mo-IM-5-R and Mo-IM-5-S) were prepared for the methane non-oxidative aromatization. The physical properties and acidities of the samples were characterized by XRD, SEM, BET and IR spectroscopy. Compared with Mo-IM-5-S, the Mo-IM-5-R catalyst showed both a higher conversion of methane and higher selectivity to benzene in methane aromatization. A higher catalytic activity of Mo-IM-5-R may be attributed to the preferable textural properties and acidities of zeolite IM-5-R. Moreover, the catalyst prepared by the physical mixing method exhibited lower initial activity, but better stability for methane aromatization than that prepared by the impregnation method.
Co-reporter:Zhifang Li;Shujie Wu;Yuanyuan Ma;Heng Liu;Jing Hu
Transition Metal Chemistry 2013 Volume 38( Issue 3) pp:243-251
Publication Date(Web):2013 April
DOI:10.1007/s11243-012-9684-2
Encapsulation of tetraazamacrocyclic complexes of Co(II), Cu(II) and V(IV) into zeolite-Y has been accomplished, and the resulting materials were used as heterogeneous catalysts for aerobic oxidation of styrene. The materials were prepared by a ship-in-a-bottle method, in which the transition metal cations were first ion-exchanged into zeolite-Y and then reacted with ethylenediamine, followed by acetylacetone. The pure tetraazamacrocyclic complexes were characterized by FTIR, solid UV–Vis and elemental analysis. The structural integrity throughout the immobilization procedure, the successful immobilization of the macrocyclic complexes, and the loadings of metal ions and macrocyclic ligands were determined by characterization techniques such as FTIR, diffuse reflection UV–Vis, inductively coupled plasma atomic emission spectroscopy, scanning electron microscopy, TG/DTA and powder X-ray diffraction. Compared with their homogeneous analogues, the catalytic properties of the encapsulated macrocyclic complexes in the oxidation of styrene with air were investigated. The immobilized complexes proved to be active catalysts and could be reused without significant loss in activity.
Co-reporter:Zhifang Li, Hong Ding, Shujie Wu, Heng Liu, Hailiang Su, Jian Sun, Dafang Zheng, Qisheng Huo, Jingqi Guan, Qiubin Kan
Materials Research Bulletin 2013 48(5) pp: 1920-1926
Publication Date(Web):
DOI:10.1016/j.materresbull.2013.01.046
Co-reporter:Heng Liu, Shuang Yang, Jing Hu, Fanpeng Shang, Zhifang Li, Chen Xu, Jingqi Guan, Qiubin Kan
Fuel Processing Technology 2012 Volume 96() pp:195-202
Publication Date(Web):April 2012
DOI:10.1016/j.fuproc.2011.12.034
The mesoporous ZSM-5-S and ZSM-5-M samples were synthesized by using ordered mesoporous carbon (CMK-3) and disordered carbon rods (C-MCM-41) as the hard template, respectively, and for comparison, conventional ZSM-5-C was also synthesized with the same synthesis composition and procedure except for the presence of carbon template. The mesoporous ZSM-5 samples exhibited similar geometrical shape, but different pore properties than the conventional ZSM-5. Moreover, Mo-modified catalysts, Mo-ZSM-5-C, Mo-ZSM-5-S and Mo-ZSM-5-M, were prepared for the non-oxidative aromatization of methane. The physical properties and acidities of the samples were characterized by XRD, SEM, TEM, BET and IR spectroscopy. Compared with Mo-ZSM-5-C, the Mo-ZSM-5-S and Mo-ZSM-5-M catalysts showed similar conversions of methane, but higher yields of aromatics. In addition, Mo-ZSM-5-S and Mo-ZSM-5-M were more stable than Mo-ZSM-5-C. The exceptional catalytic behavior of Mo-modified mesoporous ZSM-5 catalysts may be attributed to the generation of secondary mesoporous systems within the zeolite crystal, which may lead to easier access to the active sites for reactants and be favorable for the diffusion of larger molecule product formed in the microporous channels during the methane aromatization reaction.
Co-reporter:Chunhua Wang, Fanpeng Shang, Xiaofang Yu, Jingqi Guan, Qiubin Kan
Applied Surface Science 2012 Volume 258(Issue 18) pp:6846-6852
Publication Date(Web):1 July 2012
DOI:10.1016/j.apsusc.2012.03.117
Abstract
Acid–base bifunctional mesoporous catalysts Al-SBA-15-NH2 containing high content of Al and organic amine functional groups have been synthesized through the “pH-adjusting” method. The materials were characterized by X-ray diffraction (XRD), scanning electron micrographs (SEM), transmission electron micrographs (TEM), Fourier-transform infrared spectroscopy (FTIR), IR spectra of pyridine adsorption, NH3-TPD and elemental analysis. Catalytic results showed that 6-Al-SBA-15-NH2 (Si/Al = 6 mol%) was more active than 10-Al-SBA-15-NH2 (Si/Al = 10 mol%) in one-pot deacetalization–Knoevenagel and deacetalization–nitroaldol (Henry) reactions.
Co-reporter:Zhifang Li;Lulu Liu;Jing Hu;Heng Liu;Shujie Wu;Qisheng Huo;Jingqi Guan
Applied Organometallic Chemistry 2012 Volume 26( Issue 5) pp:252-257
Publication Date(Web):
DOI:10.1002/aoc.2861
A novel type of oxovanadium(IV) 8-hydroxyquinoline (8-Q) complex and oxovanadium(IV) acetylacetonate (acac) complex were synchronously anchored on to amino-modified SBA-15 (named VO(acac:8-Q)-SBA-15) and examined as a catalyst for styrene oxidation. The structure of the synthesized catalyst was characterized by means of X-ray diffraction (XRD), FT-IR, diffusion reflection UV–visible, inductively coupled plasma atomic emission spectroscopy (ICP-AES), scanning electron microscopy (SEM), and thermogravimetric analysis (TG). Characterizations with FT-IR, diffusion reflection UV-visible, ICP-AES and TG suggested the incorporation of oxovanadium(IV) complex in amino-modified SBA-15. XRD and SEM results indicated that SBA-15 remained intact throughout the grafting procedure. It was found that VO(acac:8-Q)-SBA-15 catalyst was more active than single-ligand catalysts VO(acac)2-SBA-15 and VO(8-Q)2-SBA-15 and that the product selectivity varied in cases of different oxidants. The catalyst VO(acac:8-Q)-SBA-15 with two different ligands showed high yield of styrene oxide (45.8%) and good recoverability when using air as oxidant. Copyright © 2012 John Wiley & Sons, Ltd.
Co-reporter:Fanpeng Shang, Jianrui Sun, Heng Liu, Chunhua Wang, Jingqi Guan, Qiubin Kan
Materials Research Bulletin 2012 47(3) pp: 801-806
Publication Date(Web):
DOI:10.1016/j.materresbull.2011.11.055
Co-reporter:Yanqiu Shao, Heng Liu, Xiaofang Yu, Jingqi Guan, Qiubin Kan
Materials Research Bulletin 2012 47(3) pp: 768-773
Publication Date(Web):
DOI:10.1016/j.materresbull.2011.12.001
Co-reporter:Fanpeng Shang, Jianrui Sun, Shujie Wu, Heng Liu, Jingqi Guan, Qiubin Kan
Journal of Colloid and Interface Science 2011 Volume 355(Issue 1) pp:190-197
Publication Date(Web):1 March 2011
DOI:10.1016/j.jcis.2010.10.042
A series of efficient acid–base bifunctionalized hexagonal mesoporous silica (HMS) catalysts contained aminopropyl and propanesulfonic acid have been synthesized through a simple co-condensation by protection of amino group. The results of small-angle XRD, TEM, and N2 adsorption–desorption measurements show that the resultant materials have mesoscopic structures. X-ray photoelectron spectroscopies, elemental analysis (EA), back titration, 29Si NMR and 13C NMR confirm that the organosiloxanes were condensed as a part of the silica framework. The resultant catalysts exhibit excellent acid-basic properties, which make them possess high activity for one-pot deacetalization–Knoevenagel and deacetalization–nitroaldol (Henry) reactions.Graphical abstractA series of efficient acid–base bifunctionalized hexagonal mesoporous silica (HMS) catalysts have been synthesized. The novel catalysts possess high activity for cascade reactions.Research highlights► Acid-base bifunctionalized hexagonal mesoporous silica catalysts. ► Synthesized through protection of amino group. ► Exhibit excellent acid-basic properties. ► Possess high activity for one-pot cascade reactions.
Co-reporter:Chen Xu, Heng Liu, Mingjun Jia, Jingqi Guan, Shujie Wu, Tonghao Wu, Qiubin Kan
Applied Surface Science 2011 Volume 257(Issue 7) pp:2448-2454
Publication Date(Web):15 January 2011
DOI:10.1016/j.apsusc.2010.10.001
Abstract
A series of ZSM-5 zeolites were synthesized by adding triethoxyphenylsilane (PTEOS) into the initial sol of the synthesis system. The samples were studied by XRD, SEM, N2 adsorption–desorption and acid assessment of d3-acetonitrile adsorption. Characterization results showed that the crystal size of the ZSM-5 zeolites could be adjusted in a certain range by introducing different contents of PTEOS. Besides, the resultant materials possess hierarchical porosity in addition to those micropores generated by the MFI channels. Moreover, supported Mo/ZSM-5 catalysts were prepared, and their catalytic performances were investigated in the methane non-oxidative aromatization. It was found that the Mo/ZSM-5 catalyst, bearing suitable crystal size and mesoporous characteristic showed relatively high shape-selectivity to benzene and high stability for the reaction of methane aromatization.
Co-reporter:Shujie Wu;Ke Song;Jingqi Guan
Bulletin of Materials Science 2011 Volume 34( Issue 4) pp:
Publication Date(Web):2011 July
DOI:10.1007/s12034-011-0225-y
Super-microporouos silicon material with high hydrothermal stability denoted as MCM-41-T has been prepared from mesoporous MCM-41 by high temperature treatment. The structural and chemical property of MCM-41-T has been characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption, infrared spectroscopy and 29Si MAS NMR. The characteristic results show that Si-OH groups are forced to condense by high temperature treatment, and the pore size of MCM-41-T is around 1.5 nm in the super-microporous range. Compared with the original material MCM-41, the hydrothermal stability of MCM-41-T has been significantly enhanced.
Co-reporter:Fanpeng Shang;Shujie Wu;Jingqi Guan
Reaction Kinetics, Mechanisms and Catalysis 2011 Volume 103( Issue 1) pp:181-190
Publication Date(Web):2011 June
DOI:10.1007/s11144-011-0290-7
Two samples of aminopropyl-functionalized silica (APS) have been prepared by grafting an organosilane precursor 3-aminopropyl-triethoxysilane onto the SBA-15 in ethanol or toluene. Aminopropyl-functionalized silica-E (sample grafted in ethanol) and APS-T (sample grafted in toluene) were evaluated in carbon–carbon bond forming reactions such as the Knoevenagel condensation and the Claisen–Schmidt condensation. It has been found that the sample grafted in ethanol displayed better catalytic properties than the sample grafted in toluene. The surface silanol groups, which were proven to be more numerous in samples grafted in ethanol compared to those grafted in toluene, were found to be responsible for the enhanced catalytic activity in carbon–carbon bond forming reactions.
Co-reporter:Yanqiu Shao, Jingqi Guan, Shujie Wu, Heng Liu, Bo Liu, Qiubin Kan
Microporous and Mesoporous Materials 2010 Volume 128(1–3) pp:120-125
Publication Date(Web):March 2010
DOI:10.1016/j.micromeso.2009.08.013
Two acid–base bifunctional mesoporous materials Benzyl-APS-S-SBA-15 and Anthracyl-APS-S-SBA-15 (APS: (3-trimethoxysilanyl-propyl)-amine) were successfully synthesized by a direct synthesis method. The influence of steric hindrance upon prevention of interaction between acid and base was investigated by using two different secondary amines, benzyl-(3-trimethoxysilanyl-propyl)-amine and anthracyl methyl-(3-trimethoxysilanyl-propyl)-amine. X-ray diffraction (XRD), N2 adsorption, thermogravimetric analysis (TGA), scanning electron micrographs (SEM), transmission electron micrographs (TEM), elemental analysis, back titration, and 29Si magic-anglespinning (MAS) NMR were employed to characterize the synthesized mesoporous bifunctional materials. The experimental results indicate that the guests can be well dispersed in the channel of SBA-15, and the obtained materials exhibit excellent acid–basic properties, which make it possess high activity for the aldol condensation of acetone with 4-nitrobenzaldehyde.
Co-reporter:Ying Yang, Jingqi Guan, Pengpeng Qiu, Qiubin Kan
Applied Surface Science 2010 Volume 256(Issue 10) pp:3346-3351
Publication Date(Web):1 March 2010
DOI:10.1016/j.apsusc.2009.12.032
Abstract
Schiff base functionalized SBA-15 mesoporous materials were synthesized by post-grafting of salicylaldehyde onto silylated and non-silylated amino-modified SBA-15 and followed by the introduction of Cu(II) ions via a ligand exchange reaction. Both hybrid materials prepared were characterized by XRD, FT-IR, UV–vis spectroscopy, N2 adsorption/desorption, TG/DTA and ICP-AES techniques and comparatively examined as catalysts in epoxidation of styrene with 30 wt.% aqueous hydrogen peroxide as oxidant. It was found that the silylated material was more active and selective to styrene oxide than the non-silylated one in CH3CN. The considerably improved activity (86.1%) and styrene oxide selectivity (95.2%) were achieved after 30 min when adding sodium hydroxide to maintain a pH of 7.5–8.0 in reaction medium. Moreover, the silylated catalyst showed good recoverability and relatively high stability against leaching of active copper species. These superior effects were attributed to the high hydrophobic character of the solid surface produced by the silanol neutralization.
Co-reporter:Zhuqian Wang, Jingqi Guan, Shujie Wu, Chen Xu, Yuanyuan Ma, Jinhua Lei, Qiubin Kan
Materials Letters 2010 Volume 64(Issue 11) pp:1325-1327
Publication Date(Web):15 June 2010
DOI:10.1016/j.matlet.2010.03.027
A new method was developed for preparation of silicalite-1 microspheres with uniform diameter about 2.5 μm using monodispersed micron-sized poly- styrene-co-divinylbenzene (PSD) porous particles as template. In this method, the PSD particles were impregnated first with tetraethoxysilane (TEOS) and then with tetrapropylammonium hydroxide (TPAOH). After crystallization and calcination, the silicalite-1 microspheres, possessing a regularly spherical morphology similar to the original silicalite-1, were successfully synthesized. More importantly, the silicalite-1 microspheres have large secondary pores in the range of 40 to 120 nm and high pore volume up to 0.7 cm3g− 1. All these would facilitate the applications of microspheres in catalysis avoiding diffusion limitation.
Co-reporter:Ling Xu, Yuanyuan Ma, Wenli Ding, Jingqi Guan, Shujie Wu, Qiubin Kan
Materials Research Bulletin 2010 45(9) pp: 1293-1298
Publication Date(Web):
DOI:10.1016/j.materresbull.2010.04.024
Co-reporter:Ying Yang;Jingqi Guan;Pengpeng Qiu
Transition Metal Chemistry 2010 Volume 35( Issue 3) pp:263-270
Publication Date(Web):2010 April
DOI:10.1007/s11243-009-9322-9
A series of hybrid mesoporous SBA-15 materials containing four iron(III) Schiff base complexes of the type [FeLx(NO3)] (x = 4–7, L = N,N′-bis(salicylidene)ethylenediamine, N,N′-bis(salicylidene)diethylenetriamine, N,N′-bis(salicylidene)o-phenylenediamine, N,N′-bis(3-nitro-salicylidene)ethylenediamine) was synthesized by a post-grafting route. The XRD, N2 adsorption/desorption and TEM measurements confirmed the structural integrity of the mesoporous hosts, and the spectroscopic characterization techniques (FT-IR, UV–vis spectroscopy, 1H NMR) confirmed the ligands and the successful anchoring of iron(III) Schiff base complexes over the modified mesoporous support. Quantification of the supported ligand and metal was carried out by TG/DSC and ICP-AES techniques. The catalyst FeL7-SBA resulting from N,N′-bis(3-nitro-salicylidene)ethylenediamine) ligand was considerably active for the aerobic epoxidation of styrene, in which the highest conversion of styrene reached 83.6%, and the selectivity to styrene oxide was 83.0%. Moreover, it was also found that the catalytic activity increases with the decrease in the electron-donating ability of the Schiff bases, and the selectivity varies according to the types of substituents in the ligands.
Co-reporter:Ying Yang;Shijie Hao;Pengpeng Qiu
Reaction Kinetics, Mechanisms and Catalysis 2010 Volume 100( Issue 2) pp:363-375
Publication Date(Web):2010 August
DOI:10.1007/s11144-010-0182-2
Salicylaldimine functionalized SBA-15 hybrid mesoporous material was synthesized by post-grafting of salicylaldehyde modified 3-aminopropyltriethoxysilane and followed by introducing Cu(II) ions into the hybrid material via a ligand exchange reaction. The prepared catalyst was characterized by means of XRD, N2 adsorption/desorption, SEM, FT-IR, UV–vis spectroscopy, EPR and XPS techniques as well as ICP-AES and elemental analysis measurements. The solid catalyst was evaluated in the oxidation of styrene with H2O2 as the oxidant under mild conditions, and the reaction parameters (the molar ratio of styrene/H2O2, amount of catalyst, temperatures, solvents, alkaline additive) were investigated and optimized for the oxidation of styrene. The optimal conversion (77.1%) and yield of styrene oxide (60.0%) were obtained at 80 °C using CH3CN as the solvent under basic conditions. Moreover, the covalently anchored Cu(II) salicylaldimine complex showed good recoverability and high stability against leaching of active copper(II) species.
Co-reporter:Jingqi Guan;Zhuqian Wang;Chen Xu;Ying Yang;Bo Liu;Xiaofang Yu
Catalysis Letters 2009 Volume 128( Issue 3-4) pp:356-362
Publication Date(Web):2009 March
DOI:10.1007/s10562-008-9753-5
A series of vanadium phosphorus oxides (VPO) were prepared by using dodecyl amine as surfactant and tested for the partial oxidation of isobutane and isobutene. Characterization results showed that their structure and properties depend on the content of dodecyl amine. Catalytic tests showed that relatively high isobutane conversion and desired product selectivity can be achieved over a proper dodecyl amine doping VPO catalyst. It is also found that higher isobutane conversion can be achieved over V4+-containing phases as compared to V5+-containing phases, while proper surface V5+/V4+ ratio may be propitious to obtain high selectivity to methacrylic acid for the selective oxidation of isobutane. In addition, the content of dodecyl amine in the preparation of the VPO catalysts appears to be more important in determining the surface P/V ratio of the catalysts.
Co-reporter:Jingqi Guan;Cheng Xu;Zhuqian Wang;Ying Yang;Bo Liu;Fanpeng Shang
Catalysis Letters 2008 Volume 124( Issue 3-4) pp:
Publication Date(Web):2008 August
DOI:10.1007/s10562-008-9496-3
A series of Te–Mo–O catalysts were prepared by decomposing (NH4)4TeMo6O22 · 2H2O telluromolybdate under different conditions and tested for the oxidation of isobutane and isobutene. Characterization results (XRD, FTIR, TG, TPR, XPS, and BET) showed that their structure and properties depend on calcination conditions. Catalytic tests showed that molybdenum may be the key element for the activation of isobutane, whereas the selective oxidation of isobutene to methacrolein (MAL) might proceed mainly on the surface of the TeMo-containing crystalline phase. Thus, relatively high selectivities and yields of MAL and methacrylic acid (MAA) can be obtained over these specially designed catalysts.
Co-reporter:Ke Song;Jingqi Guan;Shujie Wu;Ying Yang;Bo Liu
Catalysis Letters 2008 Volume 126( Issue 3-4) pp:333-340
Publication Date(Web):2008 December
DOI:10.1007/s10562-008-9626-y
Using zeolite MCM-22 as source and cetyltrimethylammonium bromide (CTAB) as template, mesoporous material denoted as M-MCM-22 with enhanced acidity has been synthesized and characterized by XPD, FT-IR, N2 adsorption–desorption, 27Al-MAS NMR, IR spectra of pyridine adsorption, and NH3-TPD techniques, etc. The catalytic performance of M-MCM-22 was tested in alkylation of phenol with tert-butanol, indicating that M-MCM-22 showed highly and steadily catalytic properties. The highest conversion of phenol could be achieved at 418 K, while the highest selectivity to 2, 4-di-TBP was obtained at 398 K. It is found that high temperature is advantageous to form 4-TBP, whereas low weight hourly space velocity (WHSV/h−1) is helpful for both conversion of phenol and selectivity to 2,4-DTBP. It is also shown that high ratio of tert-butanol/phenol is beneficial for obtaining high conversion of phenol and selectivity to 2,4-di-TBP.
Co-reporter:Jingqi Guan;Ying Yang;Bo Liu;Yuanyuan Ma
Reaction Kinetics, Mechanisms and Catalysis 2008 Volume 95( Issue 2) pp:313-320
Publication Date(Web):2008 December
DOI:10.1007/s11144-008-5387-2
MoV0.3Te0.17 and MoV0.3Te0.17Nb0.12 catalysts were prepared by a hydrothermal synthesis route and tested for the oxidation of isobutane and isobutene. Characterization results showed that the structure and property of Mo-V-Te-based catalysts are relatively different depending on the presence of the Nb element. Catalytic tests showed that the selectivity of methacrolein can comparatively be improved by the addition of Nb into the MoV0.3Te0.17 catalyst for the selective oxidation of isobutane.
Co-reporter:Jingqi Guan;Ke Song;Haiyan Xu;Yuanyuan Ma
Reaction Kinetics, Mechanisms and Catalysis 2008 Volume 95( Issue 2) pp:321-328
Publication Date(Web):2008 December
DOI:10.1007/s11144-008-5348-9
A series of Te-Mo-O catalysts were prepared by decomposing (NH4)6TeMo6O24·nH2O telluromolybdate under different conditions and tested for the selective oxidation of isobutane and isobutene. Characterization results showed that their structure and properties depend on the calcination conditions. Catalytic tests showed that molybdenum may be the key element for the activation of isobutane, whereas the selective oxidation of isobutene to methacrolein might proceed mainly on the surface of a TeMo-containing crystalline phase.
Co-reporter:Jingqi Guan;ShuBo Jing;Shujie Wu;Haiyan Xu
Reaction Kinetics, Mechanisms and Catalysis 2007 Volume 90( Issue 1) pp:27-33
Publication Date(Web):2007 February
DOI:10.1007/s11144-007-4887-9
A series of MoV0.3Tex (x = 0−0.3) mixed oxides were prepared and investigated for the selective oxidation of isobutane. Among them, MoV0.3Te0.23 showed the best methacrolein and methacrylic acid selectivity (as high as 17% and 16%, respectively), and the yield to methacrolein and methacrylic acid reached 3.6% and 3.5%, respectively, at 21.3% isobutane conversion at 440°C.
Co-reporter:Hongsu Wang, Jiahui Huang, Shujie Wu, Chen Xu, Lihong Xing, Ling Xu, Qiubin Kan
Materials Letters 2006 Volume 60(21–22) pp:2662-2665
Publication Date(Web):September 2006
DOI:10.1016/j.matlet.2006.01.059
A luminescent organic molecule aluminum tris(8-hydroxyquinoline) (Alq3) has been successfully introduced in the pores of amino-functionalized mesoporous SBA-15 (APS-SBA-15). An obvious blue-shifted photoluminescence (PL) of Alq3 was observed. In the pores of APS-SBA-15, the Alq3 organic molecules exhibited efficient and intense PL as monomers and the emission intensities increased with increasing Alq3 concentration.
Co-reporter:Jiahui Huang, Gong Li, Shujie Wu, Hongsu Wang, Lihong Xing, Ke Song, Tonghao Wu and Qiubin Kan
Journal of Materials Chemistry A 2005 vol. 15(Issue 10) pp:1055-1060
Publication Date(Web):11 Jan 2005
DOI:10.1039/B413906B
Through a two-step crystallization procedure, an ordered mesoporous aluminosilicate with cubic Ia3d structure denoted as MB48 has been synthesized from the assembly of preformed zeolite beta precursors, utilizing cetyltrimethylammonium bromide (CTAB) as a template. By adjusting the alkalinity during the second crystallization step, an ordered mesoporous aluminosilicate with hexagonal p6mm structure named as MB41 has also been prepared. MB48 and MB41 were characterized with PXRD, FTIR, 27Al-MAS NMR, N2 adsorption–desorption and NH3-TPD techniques, etc. Experiments show that both MB48 and MB41 are pure mesoporous phases, containing the secondary structural units of zeolite beta. Compared with conventional mesoporous aluminosilicates, MB48 and MB41 have enhanced acidity and show higher catalytic activity in the cracking of cumene and the phenol alkylation with tert-butanol.
Co-reporter:Jiahui Huang, Tonghao Wu, Shujie Wu, Hongsu Wang, Lihong Xing, Ke Song, Haiyan Xu, Yuzi Jiang, Qiubin Kan
Materials Chemistry and Physics 2005 Volume 94(2–3) pp:173-176
Publication Date(Web):15 December 2005
DOI:10.1016/j.matchemphys.2005.05.004
Ordered phenyl-functionalized mesoporous hybrids with large-pore cubic Ia3d structure have been prepared in acid conditions by co-condensation of tetraethoxysilane (TEOS) and phenyltriethoxysilane (PTES) in the presence of poly (ethylene oxide)20–poly (propylene oxide)70–poly (ethylene oxide)20 (Pluronic P123). During synthesis, the amount of PTES addition plays a crucial role for the generation of special mesostructure and only in molar percentage range of 3–8% PTES with respect to total amounts of siliceous sources, can Ia3d mesoporous hybrids be obtained. Furthermore, their pore sizes can be adjusted by simply changing ageing temperature.
Co-reporter:Qiubin Kan, Vicente Fornés, Fernando Rey and Avelino Corma
Journal of Materials Chemistry A 2000 vol. 10(Issue 4) pp:993-1000
Publication Date(Web):03 Mar 2000
DOI:10.1039/A908311A
Layered aluminosilicates and gallosilicates with kanemite structure and varied Si/M ratios have been prepared and can be transformed into mesoporous materials with MCM-41-like structure in an exchange solution of cetyltrimethylammonium chloride at pH 11.0–11.7 and 20–80°C or at pH < 9.6 and 80°C. The metal ions in both the layered metallosilicates and the corresponding mesoporous materials are in a tetrahedral environment. Together with the hydrolysis of the layered aluminosilicates (Al-kanemite) it is suggested that aluminium is incorporated into the framework of the layered materials. The formation of mesoporous materials derived from the layered aluminosilicates is believed to occur through lamellar phases at pH 11.0–11.7. One characteristic lamellar phase with a basal spacing of ca. 32 Å has been obtained at pH 10.6 at 80°C, which can be partly transformed into mesoporous materials when the pH of exchange solution is reduced to a value of between 8.0 and 8.5. The lamellar phase has inorganic layers in a higher degree of silicate condensation, and is perhaps the reason that it does not form the hexagonal array at higher pH, such as pH 11.7 or 12.0. After removing the surfactant template and sodium ions by extraction with heptane–ethanol containing a small amount of hydrochloric acid, the mesoporous materials derived from the layered aluminosilcates in the exchange medium at pH 11.7 and 80°C have Brønsted and Lewis acidity similar to Al-MCM-41. In contrast, no significant acid sites have been detected over the mesoporous samples obtained at pH < 9.6 and at 80°C.
Co-reporter:Zhifang Li, Shujie Wu, Changlong Yang, Yuanyuan Ma, Xiaoran Fu, Ling Peng, Jingqi Guan, Qiubin Kan
Molecular Catalysis (May 2017) Volume 432() pp:267-273
Publication Date(Web):1 May 2017
DOI:10.1016/j.mcat.2017.02.001
•Novel magnetic nanocatalyst involving Co3O4 immobilized onto N-doped RGO/Fe3O4@C was successfully prepared.•RGO/Fe3O4@C-N-Co3O4 showed 93.2% conversion of styrene and 88.4% selectivity to the styrene oxide using air as oxidant.•The magnetic nanocatalyst exhibited excellent recoverability due to superparamagnetism.The epoxidation of alkenes to the corresponding epoxides plays a vital role in fine chemical engineering. Magnetic nanocomposite catalyst RGO/Fe3O4@C-N-Co3O4 (RGO: reduced graphene oxide) involving Co3O4 nanoparticles immobilized on magnetic N-doped graphene was prepared by a hydrothermal method. N-dopants in the RGO/Fe3O4@C-N-Co3O4 can strengthen the interaction between Co3O4 nanoparticles and the support. RGO/Fe3O4@C-N-Co3O4 revealed higher catalytic reactivity (i.e. 93.2% conversion of styrene and 88.4% selectivity to styrene oxide) as compared to bulk Co3O4, and Co3O4 supported on N-free RGO/Fe3O4@C due to site-isolation, good dispersion of Co3O4 nanoparticles and efficiently synergistic effect between Co3O4 and the magnetic support. In addition, the catalyst displayed good recoverability by simple magnetic separation with negligible loss in activity and selectivity within several successive runs due to superparamagnetism.Novel core@shellstructuredmagneticnanocatalystsinvolvingN-dopedhybridizationofgraphenesheetsandcarbon-coatedFe3O4nanoparticles(RGO/Fe3O4@C-N) immobilized Co3O4 were prepared by a facile, green and efficient chemical approach and used as efficient heterogeneous catalysts for aerobic oxidation of styrene using air as oxidant without any reducing agent. RGO/Fe3O4@C-N-Co3O4 Exhibits 93.2% conversion of styrene and 88.4% selectivity to the styrene oxide and shows excellent recoverability without loss in activity and selectivity within successive runs. Besides, the synthesized catalyst can be easily recovered via simple magnetic separation and be reused for many times.Download full-size image
Co-reporter:Fanpeng Shang, Heng Liu, Jianrui Sun, Bo Liu, Chunhua Wang, Jingqi Guan, Qiubin Kan
Catalysis Communications (31 March 2011) Volume 12(Issue 8) pp:739-743
Publication Date(Web):31 March 2011
DOI:10.1016/j.catcom.2011.01.010
A new type of acid-base bifunctional mesoporous catalyst is prepared by the modification of Al-MCM-41 surfaces with organic amine functional groups. The ratio of acidic and basic sites on the solid surface can be adjusted by varying the amount of 3-aminopropyl-triethoxysilane (APTES) in the reaction medium (toluene). The acid-base bifunctional catalysts show high catalytic activities and selectivities in one-pot deacetalization–Knoevenagel and deacetalization–nitroaldol (Henry) reactions. The cohabiting of acidic and basic sites in the materials acting in a cooperative way to catalyze nitroaldol (Henry) reaction is also demonstrated.Download full-size imageResearch Highlights► Acid-base bifunctional hexagonal mesoporous silica catalysts. ► Synthesized by simply grafting. ► Possess high activity for One-pot cascade reactions. ► An acid-base cooperative manner to catalyze nitroaldol reaction.
Co-reporter:Ying Yang, Ying Zhang, Shijie Hao, Qiubin Kan
Catalysis Communications (30 April 2010) Volume 11(Issue 9) pp:808-811
Publication Date(Web):30 April 2010
DOI:10.1016/j.catcom.2010.02.021
A metal-template/metal-exchange method was used for the covalent attachment of a discrete bis(8-quinolinol)oxovanadium(IV) complex onto mesoporous silica SBA-15 to obtain a heterogeneous catalyst VOIVT. For comparison, its homogeneous counterpart VOIVN and the randomly ligand-grafted heterogeneous analogue VOIVG were also prepared. UV–vis spectra of the VOIV catalysts show VOIVT adopts a more solution-like bis(8-quinolinol) coordination environment than VOIVG. Correspondingly, olefin epoxidation with tert-butyl hydroperoxide shows VOIVT has improved reactivity, epoxide selectivity and recyclability than VOIVN or VOIVG. The homogeneity of the discrete bis(8-quinolinol)oxovanadium(IV) complex immobilized on SBA-15 should be responsible for the superior performances of the templated catalyst.
Co-reporter:Jingqi Guan, Shujie Wu, Hongsu Wang, Shubo Jing, Guojia Wang, Kaiji Zhen, Qiubin Kan
Journal of Catalysis (25 October 2007) Volume 251(Issue 2) pp:354-362
Publication Date(Web):25 October 2007
DOI:10.1016/j.jcat.2007.07.028
A series of Mo-based catalysts (MoVCeO, MoTeCeO, MoVTeO, and MoVTeCeO mixed metal oxides) were prepared and tested for the oxidation of isobutane and isobutylene. Characterization results (XRD, FTIR, TPR, XPS, and BET) showed that their structure and properties depend on the composition of the calcined samples. Catalytic tests showed that molybdenum may be the key element for the activation of isobutane, whereas the selective oxidation of isobutylene to methacrolein (MAL) might proceed mainly on the surface of the TeMo-containing crystalline phase. In addition, Te4+ may favor the formation of methacrylic acid (MAA). The incorporation of Ce ions may modify the redox process of the catalysts and thus influence the catalytic behaviors for the selective oxidation of isobutane. Thus, the selectivities and yields of MAL and MAA can be increased over these specially designed catalysts.
![Phenol, 2-[[[3-(triethoxysilyl)propyl]imino]methyl]-](/data/chemimg/129500/215367-19-4.png)
![Phenol, 2-[[[3-(triethoxysilyl)propyl]imino]methyl]-](/data/chemimg/129500/215367-19-4_b.png)
