Co-reporter:Chen Wang, Yuan-Ye Jiang, and Chen-Ze Qi
The Journal of Organic Chemistry September 15, 2017 Volume 82(Issue 18) pp:9765-9765
Publication Date(Web):August 23, 2017
DOI:10.1021/acs.joc.7b02026
Oxaziridine-based redox sulfur imidation provides a breakthrough strategy for selective modification at methionine in proteins. The chemoselectivity of imidization (N-transfer) over oxidation (O-transfer) of the thioether functionality of methionine, and the modification selectivity of methionine over other amino acids, are the key features of this strategy. To elucidate the detailed reaction mechanism and the origin of the reported chemoselectivity, a theoretical investigation on the oxaziridine-based methionine modification reaction is reported. It is found that both the N-transfer and O-transfer pathways occur in a concerted mechanism. Distortion/interaction–activation strain model analysis indicates that the N-transfer chemoselectivity is mainly controlled by the interaction energy. Orbital and charge analysis further supports that the interaction energy resulting from the orbital interaction favors the N-transfer pathway at the early stage of the reaction. The calculated reactivity of eight potential amino acid competitors with the oxaziridine shows excellent selectivity for methionine modification, consistent with the experimental observations. The scarcity of active species in neutral aqueous solution leads to the weak reactivity of tyrosine, lysine, and arginine. The stronger charge-transfer interactions between methionine and the oxaziridine compared with that for the other amino acids also play vital roles in the modification selectivity.
Co-reporter:Ruokun Feng, Hanqi Ning, Han Su, Yuan Gao, Haotian Yin, Yudan Wang, Zhen Yang, and Chenze Qi
The Journal of Organic Chemistry October 6, 2017 Volume 82(Issue 19) pp:10408-10408
Publication Date(Web):September 11, 2017
DOI:10.1021/acs.joc.7b01867
Described herein is a convenient and highly selective synthesis of alkynylated isoquinolines and biisoquinolines from various aryl ketone O-pivaloyloxime derivatives and 1,3-diynes via rhodium-catalyzed C–H bond activation. In this transformations, alkynylated isoquinolines, 3,4′- and 3,3′-biisoquinolines could be obtained respectively through changing the reaction conditions. Mechanistic investigation revealed that the C–H activation of aryl ketone O-pivaloyloxime was the key step to this reaction.
Co-reporter:Furen Zhang, Chunmei Li, Chenze Qi
Catalysis Communications 2017 Volume 99(Volume 99) pp:
Publication Date(Web):1 August 2017
DOI:10.1016/j.catcom.2017.06.012
•A domino method has been developed using sulfonic organic resin as catalyst.•The unique feature of solid acid makes the formation of pyranopyrazolopyridines.•The catalyst exhibits good catalytic activity in recyclability study.•The domino reaction follows the acid-catalyzed mechanism.An efficient domino approach for the synthesis of new pyrano[4,3-b]pyrazolo[4,3-e]pyridin-5(1H)-one derivatives has been developed using reusable sulfonic organic resin as catalyst in water. The unique feature of sulfonic organic resin makes the formation of pyrano[4,3-b]pyrazolo[4,3-e] pyridin-5(1H)-ones be possible, and avoids generating ring opening products. The plausible mechanism for this domino reaction is proposed.Download high-res image (94KB)Download full-size image
Co-reporter:Kai Cheng;Guofang Wang;Mengting Meng;Chenze Qi
Organic Chemistry Frontiers 2017 vol. 4(Issue 3) pp:398-403
Publication Date(Web):2017/02/28
DOI:10.1039/C6QO00634E
The Pd(TFA)2-catalyzed denitrogenative addition proceeded with selective C–N bond cleavage of arylhydrazines with nitriles in the presence of DABCO and HFBA under air at room temperature. Aryl ketones could be easily synthesized via the hydrolysis of the ketimine moiety generated in situ without the need for additional water.
Co-reporter:Chen Liu;Qin Wu;Jinjun Peng;Chenze Qi;Fujian Liu
Journal of Porous Materials 2017 Volume 24( Issue 2) pp:297-303
Publication Date(Web):2017/04/01
DOI:10.1007/s10934-016-0263-3
Pd and transition metal oxides functionalized ZSM-5 single crystals with b-axis aligned mesopores (ZSM-5-OM-PdOx-MOx) were prepared. ZSM-5-OM support was obtained from crystallization of aluminosilicate gels in the presence of cationic polymers. Characterizations indicate abundant nanopores and highly crystalline degree of ZSM-5-OM-PdOx-MOx, and active species of Pd and transition metals were homogeneously dispersed into ZSM-5-OM, which showed unique interactions and enhanced ability for activating oxygen. Catalytic tests showed that ZSM-5-OM-PdOx-MOx were highly active and reusable catalysts for selective oxidation of alcohols under aerobic and solvent free condition, which were much better than those of Pd/transition metal oxides functionalized ZSM-5, mesoporous silica of SBA-15, and activated carbon catalysts.
Co-reporter:Linjun Shao;Lingjuan Lian;Chenze Qi
Kinetics and Catalysis 2017 Volume 58( Issue 4) pp:370-376
Publication Date(Web):02 August 2017
DOI:10.1134/S0023158417040176
Well-defined chlorinated polyvinylchloride (CPVC) nanofiber mats were fabricated by electrospinning, and then chemically modified with 1,3-propanediamine (CPVC–NH) and glutaraldehyde (CPVC–NOH) to immobilize palladium active species. The chemical modification could significantly improve the tensile strengths of the CPVC nanofiber mats. Adsorption of Pd(II) ions showed that the treatment of fiber mats with glutaraldehyde decreases it schelating ability. Transmission electron microscopy and X-ray diffraction analysis indicated that palladium species were dispersed more homogeneously on the CPVC–NH fibers than on the CPVC–NOH fibers. Results of Mizoroki–Heck reaction showed that the catalytic activity of Pd catalyst supported on CPVC–NOH fibers was superior to that of the Pd catalyst supported on CPVC–NH fibers. Thus, chemical modification of supporting materials with suitable chelating groups is an efficient way to control the catalytic performance of supported Pd catalysts.
Co-reporter:Fujian Liu, Bojie Li, Chen Liu, Weiping Kong, Xianfeng Yi, Anmin Zheng and Chenze Qi
Catalysis Science & Technology 2016 vol. 6(Issue 9) pp:2995-3007
Publication Date(Web):19 Nov 2015
DOI:10.1039/C5CY01226K
N rich porous carbon based solid acids (NPC-[CxN][X]) have been successfully synthesized by treatment of N rich porous carbon (NPC) with various quaternary ammoniation reagents such as iodomethane, 1,3-propane sultone, and 1,4-butanesultone, and ion exchange with various strong acids such as HSO3CF3, H2SO4, H3PW12O40, HBF4etc. The NPC support was synthesized by carbonization of KOH-activated polypyrrole without using additional templates. Various characterizations showed that NPC-[CxN][X] possesses abundant nanopores, large Brunauer–Emmett–Teller surface areas, good stability, and strong and controllable acid sites with Brønsted characteristics. The immobilized acidic groups were homogeneously dispersed into NPC-[CxN][X]. Notably, NPC-[CxN][X] acted as efficient, reusable and generalized solid acids, which showed excellent activity in various acid-catalyzed reactions such as esterification and transesterification in the synthesis of biodiesel, dehydration of fructose into 5-hydroxymethylfurfural, depolymerization of crystalline cellulose into sugars, and condensation of phenol with acetone in the synthesis of bisphenol A, much higher than that of various solid acids such as Amberlyst 15, H-ZSM-5, H-USY, and sulfonic group functionalized ordered mesoporous silicas. The preparation of NPC-[CxN][X] leads to the development of porous carbon based solid acids with controllable structural characteristics and excellent catalytic activity.
Co-reporter:Chen Wang, Xiao-Rong Ren, Chen-Ze Qi, and Hai-Zhu Yu
The Journal of Organic Chemistry 2016 Volume 81(Issue 17) pp:7326-7335
Publication Date(Web):July 22, 2016
DOI:10.1021/acs.joc.6b00726
Density functional theory calculations have been carried out to study the mechanism of the gold-catalyzed highly selective hydroamination of alkylidenecyclopropanes. Two main mechanisms (i.e., double-bond activation-first and three-membered-ring activation-first mechanisms) have been examined. The double-bond activation-first mechanism results in the alkene hydroamination product, and it mainly consists of three steps: C–N bond formation, C–C bond rotation, and protodeauration (rate-determining step). Meanwhile, the three-membered-ring activation-first mechanism finally produces allylic amines, and it occurs via the ring-opening (rate-determining step), C–N bond formation, and protodeauration steps. The calculation results show good agreement with the experimental outcomes on the chemo-, regio-, and diastereoselectivity. On this basis, we found that the regioselectivity is caused by the C–C bond rotation step, while the diastereoselectivity is determined by both the C–C bond rotation and the protodeauration steps in the double-bond activation-first mechanism.
Co-reporter:Z. Wang;M. Xu;L. Shao;C. Qi
Kinetics and Catalysis 2016 Volume 57( Issue 3) pp:354-359
Publication Date(Web):2016 May
DOI:10.1134/S0023158416030149
Nonwoven chitosan (CS) nanofiber mats were successfully prepared by the electrospinning of the mixture of CS and poly(ethylene oxide) (PEO) in acetic acid aqueous solution. The CS/PEO fiber mats were treated with glutaraldehyde aqueous solution to stabilize fibers in solution. The concentration of glutaraldehyde is important for incorporating swelling properties in the cross-linked CS/PEO fiber mats. The cross-linked CS/PEO fibers (CCS/PEO fibers) were then used as supports for palladium catalysts in the Mizoroki–Heck reaction. The results of the study demonstrated that the catalytic activities of Pd catalyst supported on CCS/PEO fiber (Pd-CCS/PEO fiber) were highly dependent on the concentration of glutaraldehyde in the cross-linking process. Density functional theory (DFT) calculations indicated that the Schiff bond formed between CS and glutaraldehyde could reduce the energy needed to form a chelate complex between the CCS/PEO fibers and palladium active species. This in turn could decrease the activation energy of the Mizoroki–Heck reactions which occur in the presence of the Pd-CCS/PEO fiber catalysts. The optimized Pd-CCS/PEO fiber catalyst was very efficient and stable in the Mizoroki–Heck reaction of aromatic iodides with olefins.
Co-reporter:Fujian Liu, Weiping Kong, Liang Wang, Xianfeng Yi, Iman Noshadi, Anmin Zheng and Chenze Qi
Green Chemistry 2015 vol. 17(Issue 1) pp:480-489
Publication Date(Web):12 Sep 2014
DOI:10.1039/C4GC01052C
Strong acid ionic liquids and sulfonic group bifunctional graphene-like nanoporous carbons (GNC-SO3H-ILs) have been synthesized by treating nitrogen containing graphene-like nanoporous carbons (GNCs) with 1,3-propanesultone, ion exchanging with HSO3CF3 or H2SO4. Introducing nitrogen is important for grafting strong acid ionic liquids and sulfonic group in GNCs, which were synthesized from carbonization of a mixture of dicyandiamide or melamine and glucose. GNC-SO3H-ILs possess abundant nanopores, nanosheet structure, good dispersion and controlled acidity. By themselves, they are capable of enhancing the fast diffusion of reactants and products, while increasing the exposure degree of acidic sites in GNC-SO3H-ILs throughout various reactions. The above characteristics resulted in their much improved catalytic activity in biomass transformations such as the production of biodiesel and depolymerization of crystalline cellulose into sugars, which was even comparable to those of homogeneous ionic liquid and mineral acids.
Co-reporter:Furen Zhang, Chunmei Li, Chen Wang and Chenze Qi
Organic & Biomolecular Chemistry 2015 vol. 13(Issue 17) pp:5022-5029
Publication Date(Web):19 Mar 2015
DOI:10.1039/C5OB00129C
A facile and efficient approach has been established for the synthesis of benzoindole and naphthofuran derivatives via the metal-free cyclization reaction of nitroolefins with naphthylamines/naphthols. Various substituted benzoindoles and naphthofurans are obtained in good to excellent yields. Moreover, the ability to recycle the carbonaceous material makes this method quite cost-effective and environmentally benign compared to traditional acid-catalyzed methods. Theoretical studies indicated that the reaction between naphthylamine and nitroolefin catalyzed by this solid acid was thermodynamically controlled at 60 °C, resulting in the formation of the benzoindoles.
Co-reporter:Minfeng Zeng, Xia Yuan, Shufeng Zuo and Chenze Qi
RSC Advances 2015 vol. 5(Issue 48) pp:37995-38000
Publication Date(Web):01 Apr 2015
DOI:10.1039/C5RA01902H
The objective of this study was to develop novel chitosan-based/montmorillonite/palladium (CS/MMT/Pd) hybrid microsphere catalysts with improved properties for use in Sonogashira reactions. Interactions between a chitosan matrix and a montmorillonite nanofiller were revealed by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and thermogravimetric (TG) analysis. The results confirmed the formation of the intercalation structure between CS macromolecules and MMT layers. X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HR-TEM) analysis results showed that the Pd species of different valencies were dispersed at the nano-level in both the CS matrix and the interlayers of MMT. CS/MMT/Pd hybrid microspheres were highly active for the Sonogashira reactions of aryl iodides and alkynes at a palladium catalyst loading of 0.3 mol%. They can be recycled 10 times without a significant decrease in coupling yields. It was concluded that introducing MMT into the CS matrix will effectively improve the thermal stability and Pd leaching-resistance of the hybrid microsphere catalysts. The results in this study demonstrated the great potential of such heterogeneous catalysts applied in Sonogashira reactions.
Co-reporter:Linjun Shao, Yuan Ren, Zining Wang, Chenze Qi, Yao Lin
Polymer 2015 Volume 75() pp:168-177
Publication Date(Web):28 September 2015
DOI:10.1016/j.polymer.2015.08.031
•A general approach to obtain composite chitosan nanofibers is proposed.•The method is based on mechanistic understanding of chain entanglements in solution.•The composite fibers provide a useful platform to support a variety of catalysts.•“Post-modification” of the fibers further improves the stability of supported catalysts.Using electrospinning technique to prepare chitosan (CS) nanofibers from an inexpensive solvent such as acetic acid has been a challenge, due to the lack of sufficient entanglements in these semi-rigid polyelectrolytes. Incorporating polymers such as poly(methacrylic acid) (PMAA) into the solution lowers the entanglement concentration of the polymers, and make all three morphology regimes (polymer droplets, beaded nanofibers and nanofibers with uniform thickness) accessible to electrospinning method. Uniform composite nanofibers are found at concentrations well above the entanglement concentration. The thickness and morphology of nanofibers can be regulated by addition of small amount of organic solvents such as dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). The composite nanofibers are subsequently crosslinked at an elevated temperature to improve their thermal and solvent stability. The mechanical properties of the crosslinked CS/PMAA fibers can be modulated by varying the amount and molecular weight of PMAA incorporated in the blend. The composite fiber materials provide a useful platform to support a variety of catalysts. As a demonstration, palladium catalyst has been immobilized on the crosslinked CS/PMAA nanofibers to carry out Mizoroki–Heck cross-coupling reactions of aromatic halides and acrylates. We found remarkable catalytic efficiency and stability in these materials. We also demonstrate that, by the “post-modification” of the nanofibers with ligands that chelate metal catalysts, a variety of metal catalysts can be incorporated into the fiber platform, with further improved stability and activity.
Co-reporter:Shufeng Zuo, Xuejie Sun, Ningning Lv, and Chenze Qi
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 15) pp:11988
Publication Date(Web):July 24, 2014
DOI:10.1021/am500138q
A new type of porous kaolin/NaY composite (KL-NY) with a large specific surface area and large pore sizes was synthesized through a one-step crystallization process, and rare earth-modified KL-NY-supported Pd–Pt catalysts were studied for benzene combustion. The results indicated that the pore volume and specific surface area of KL-NY after calcination and crystallization were 0.298 cm3/g and 365 m2/g, respectively, exhibiting appropriate pore structure and good thermal stability. Catalysts with rare earth metals greatly enhanced the activity of Pd/KL-NY, and the addition of Pt and Ce into the Pd catalyst improved the catalytic activity as well as the stability. The catalyst with an optimal Ce content and Pt/Pd molar ratio (0.2%Pd–Pt (6:1)/6%Ce/KL-NY) demonstrated the best activity for the complete oxidation of benzene at 230 °C, and the catalyst above maintained the 100% benzene conversion for 960 h.Keywords: catalytic combustion; kaolin/NaY; Pd−Pt; rare earth; volatile organic compounds
Co-reporter:Fujian Liu, Gaofeng Feng, Mengyi Lin, Cong Wang, Baowei Hu, Chenze Qi
Journal of Colloid and Interface Science 2014 Volume 435() pp:83-90
Publication Date(Web):1 December 2014
DOI:10.1016/j.jcis.2014.08.010
•Superoleophilic nanoporous polymers were synthesized under solvothermal condition.•Ionic liquid groups were grafted onto the network of nanoporous polymers.•Nanoporous polymeric ionic liquids act as efficient support for palladium acetate.•The obtained Pd based catalysts have abundant nanopores and controllable wettability.•Nanoporous polymer based Pd catalysts show good catalytic activity in Suzuki reaction.We report here successful synthesis of superoleophilic, nanoporous polymeric ionic liquids supported palladium acetate (PDVB-[C3vim][SO3CF3]-Pd-xs, where x stands for the weight percentage of palladium acetate), which act as efficient heterogeneous catalysts in Suzuki–Miyaura cross-coupling reaction. PDVB-[C3vim][SO3CF3] support was synthesized from solvothermal copolymerization of divinylbenzene with vinylimidazole without using any templates, followed by functionalized with ionic liquid groups. The resultant PDVB-[C3vim][SO3CF3]-Pd-xs possess large BET surface areas, good stability, homogeneous dispersion of Pd active species, and superwettability for various aromatic reactants, which result in their much improved reactants enrichment property. The above characters make PDVB-[C3vim][SO3CF3]-Pd-xs showed much improved catalytic activity and good recyclability in Suzuki–Miyaura reaction in comparison with those of palladium acetate supported onto activated carbon and ordered mesoporous silica of SBA-15. The superior activity found in PDVB-[C3vim][SO3CF3]-Pd-xs is attributed to synergistic effects between large surface areas and unique enrichment property for various aromatic reactants, which by themselves are capable of enhancing exposition degree of Pd active sites to reactants.
Co-reporter:Chunmei Li, Furen Zhang, Zhen Yang, Chenze Qi
Tetrahedron Letters 2014 Volume 55(Issue 40) pp:5430-5433
Publication Date(Web):1 October 2014
DOI:10.1016/j.tetlet.2014.08.022
Treatment of nitroolefins and o-phenylenediamine with silica gel catalyst produced quinoxalines mainly in THF, but gave benzimidazoles efficiently in water. Such a solvent-dependent chemoselective reaction has prominent features of affording two cyclized products selectively with the same substrate, short reaction time, operational simplicity, as well as available starting materials and nontoxic catalysts. In addition, the scope and limitations were explored and a plausible reaction mechanism is proposed.
Co-reporter:Lehao Huang, Xudong Sun, Qian Li, and Chenze Qi
The Journal of Organic Chemistry 2014 Volume 79(Issue 14) pp:6720-6725
Publication Date(Web):July 7, 2014
DOI:10.1021/jo500932x
A Pd-catalyzed regioselective alkylation of C8–H bonds in 1-naphthylamides containing a quinolinamide or picolinamide moiety as a bidentate directing group with alkyl halides is reported. The amide directing group can be easily hydrolyzed under basic conditions. Various alkyl halides including alkyl iodides and benzyl bromide or chloride can be employed as coupling partners, exclusively providing 8-alkyl-1-naphthylamide derivatives.
Co-reporter:Xinyan Zheng;Weiming Fan;Weiping Kong;Yudan Wang;Chenze Qi
Kinetics and Catalysis 2014 Volume 55( Issue 5) pp:592-598
Publication Date(Web):2014 September
DOI:10.1134/S002315841405005X
The present paper describes the preparation of KF/M-γ-Al2O3, efficient mesoporous solid bases. The procedure involves loading KF into a crystalline mesoporous γ-Al2O3 that was synthesized by the self-assembly of poly-4-vinylpyridine (P4VP) with Al3+ species. The synthesis is based on the strong acid-base interaction, hydrothermal treatment at 180°C and calcination at 550°C. Characterizations using XRD analysis and low temperature N2 adsorption indicated that different amounts of KF could be introduced into crystalline mesoporous γ-Al2O3 to obtain catalysts with high BET surface areas, large pore volumes and uniform pore size distribution. Based on SEM images, KF/M-γ-Al2O3 catalysts have rough surface character and a large nanopore volume. CO2-TPD curves registered for KF/M-γ-Al2O3 contain high temperature peaks, indicating strong basicity of the catalysts. Under the same reaction conditions KF/M-γ-Al2O3 catalysts exhibit much better activities for transesterification to biodiesel than KOH, NaOH, H2SO4, hydrotalcite and CaO. Enhanced activities appear to arise from strong basisity and large BET surface areas.
Co-reporter:Lin-Jun Shao;Gui-Ying Xing
Chemical Papers 2014 Volume 68( Issue 7) pp:983-988
Publication Date(Web):2014 July
DOI:10.2478/s11696-013-0527-1
Spherical melamine-formaldehyde resin (MFR) particles were synthesised using the condensation reaction of melamine and formaldehyde with PEG-2000 as an additive. After thermal treatment at 200°C and then sulphonation by chlorosulphuric acid, an MFR-supported strong acid catalyst (SMFR) was prepared with an acidity of 3.23 mmol g−1. This new acid catalyst was evaluated in the reactions of esterification and acetalisation, with the results indicating that this novel acid catalyst was highly efficient in the traditional acid-catalysed reaction. Its high activity, stability and reusability give it great potential for “green” chemical processes.
Co-reporter:Linjun Shao;Chenze Qi
Fibers and Polymers 2014 Volume 15( Issue 11) pp:2233-2237
Publication Date(Web):2014 November
DOI:10.1007/s12221-014-2233-1
Nanoporous preoxidated polyacrylonitrile fiber mat was prepared by electrospinning and thermal treatment for the immobilization of palladium catalyst. The fiber morphologies were characterized by scanning electron microscopy (SEM). Infrared spectra and X-ray powder diffraction characterizations (XRD) showed that thermal treatment of fiber mat could change the linear polyacrylonitrile structure into ladder structure. XRD was used to study the chemical nature of the palladium in the fiber mat. The catalytic activity and stability of the fiber supported palladium catalyst have been evaluated by the Mizoroki-Heck and Sonogashira cross-couplings. The larger structure of the fiber mat can greatly facilitate its separation and recycling. The excellent catalytic performance and easy recycling made this novel fiber mat supported palladium catalyst hold great potential for the green chemical processes.
Co-reporter:Fujian Liu, Shufeng Zuo, Xiaodan Xia, Jing Sun, Yongcun Zou, Liang Wang, Chunguang Li and Chenze Qi
Journal of Materials Chemistry A 2013 vol. 1(Issue 12) pp:4089-4096
Publication Date(Web):21 Jan 2013
DOI:10.1039/C3TA01505J
We report here a generalized synthesis of various crystalline mesoporous metal oxides including CeO2, Cr2O3, Fe2O3, SnO2, Ce0.5Zr0.5O2, TiO2, Al2O3 and ZrO2 from the self-assembly of a basic poly 4-vinylpyridine (P4VP) template with various metal precursors based on their strong acid–base interaction under high temperature (180 °C) hydrothermal conditions. Using the typically crystalline mesoporous metal oxide of CeO2, after removing the template by calcination at 550 °C and loading with various transition metal oxides such as MnOx, various transition metal oxide functionalized crystalline mesoporous CeO2 (MnOx/P4VP–CeO2) were obtained. X-ray diffraction (XRD) patterns show that the resulting mesoporous metal oxides exhibit a high degree of crystallinity, and the transition metal oxides active sites have been successfully loaded into these samples. N2 sorption–desorption isotherms, SEM images show that the resulting crystalline mesoporous metal oxides, such as CeO2, have a large BET surface area (94 m2 g−1) and abundant mesopores, which exhibit monolithic morphology with crystal sizes ranging from 5 to 15 μm, giving a uniform pore size centered at 5 nm. XPS spectra show that the active sites such as MnOx exhibit the phases of MnO2 and Mn2O3 in P4VP–CeO2. H2-TPR curves show that MnOx/P4VP–CeO2 exhibits decreased reductive temperatures of both active sites of the MnOx and P4VP–CeO2 supporter when compared with the samples reported previously. More importantly, MnOx/P4VP–CeO2 exhibits much better catalytic activities and good recyclability for catalyzing the oxidation of benzene than that of MnOx loaded commercially crystalline CeO2, which will be very important for their wide applications for VOCs removal in industry.
Co-reporter:Fujian Liu, Ranjan K. Kamat, Iman Noshadi, Daniel Peck, Richard S. Parnas, Anmin Zheng, Chenze Qi and Yao Lin
Chemical Communications 2013 vol. 49(Issue 76) pp:8456-8458
Publication Date(Web):31 Jul 2013
DOI:10.1039/C3CC44703K
The acidic ionic liquid (IL) functionalized polymer (PDVB–SO3H–[C3vim][SO3CF3]) possesses abundant nanoporous structures, strong acid strength and unique capability for deconstruction of crystalline cellulose into sugars in ILs. The polymer shows much improved catalytic activities in comparison with mineral acids, homogeneous acidic ionic liquids and the acidic resins such as Amberlyst 15. The enhanced catalytic activity found in the polymer is attributed to synergistic effects between the strongly acidic group and the ILs grafted onto the polymer, which by itself is capable of breaking down the crystalline structures of cellulose. This study may help develop cost-effective and green routes for conversion of biomass to fuels.
Co-reporter:Kai Cheng, Baoli Zhao, Sai Hu, Xian-Man Zhang, Chenze Qi
Tetrahedron Letters 2013 Volume 54(Issue 46) pp:6211-6214
Publication Date(Web):13 November 2013
DOI:10.1016/j.tetlet.2013.09.001
Pd-catalyzed cross-coupling reactions of various arenediazonium salts with ArSi(OR)3 and KArBF3 have been achieved in good to excellent yields under simple aerobic conditions in water at room temperature. The functional group tolerance makes these transformations as attractive alternatives to the traditional cross-coupling approaches. Furthermore, the sequence can also be performed in a one-pot domino process, omitting the isolation of the intermediate arenediazonium salt.
Co-reporter:Ping Xia;Chen Wang;Chenze Qi
Chinese Journal of Chemistry 2013 Volume 31( Issue 6) pp:813-818
Publication Date(Web):
DOI:10.1002/cjoc.201300035
Abstract
Cyclization is an important chemical reaction for the dipeptides containing N-alkyl groups. The cyclization mechanism has been examined by theoretical calculations. Our calculation results indicate that the most favorable mechanism is the piperidine-catalyzed stepwise mechanism, in which piperidine acts as a proton shuttle. The attack of the N-terminal amino nitrogen at the C-terminal carbonyl carbon along with the proton transfer is the rate-limiting step. The effect of the alkyl substituent on the amide N on the cyclization reaction was then examined. Finally, the influence of the solvation effect, electronic effect and steric effect on the cyclization was investigated. It is found that all of these effects contribute to the cyclization.
Co-reporter:Sai Hu;Ping Xia;Kai Cheng;Chenze Qi
Applied Organometallic Chemistry 2013 Volume 27( Issue 3) pp:188-190
Publication Date(Web):
DOI:10.1002/aoc.2970
Palladium-catalyzed cross-coupling reactions of various aryl sulfinic acid salts with a wide variety of vinyl substrates have been achieved in good to excellent yields under simple aerobic conditions at 70°C with the assistance of Cu(II) salts. The reaction can be accelerated by the combination of DMSO with THF. The reported Matsuda–Heck type coupling reactions are tolerant to the common functional groups, making these transformations as attractive alternatives to the traditional cross-coupling approaches. Copyright © 2013 John Wiley & Sons, Ltd.
Co-reporter:Linjun Shao;Guiying Xing;Weixi Lv;Huijun Yu;Mingxi Qiu;Xian-Man Zhang;Chenze Qi
Polymer International 2013 Volume 62( Issue 2) pp:289-294
Publication Date(Web):
DOI:10.1002/pi.4298
Abstract
Electrospinning has been employed to fabricate uniform polyacrylonitrile and polyacrylonitrile copolymer nanofiber mats supporting metalloporphyrins (MTPP; M: Zn(II), Cu(II), Ni(II), Co(II), Fe(III) and Pd(II); TPP: meso-tetraphenylporphyrin). The nanofiber mat-supported metalloporphyrins are shown as efficient photocatalysts for the degradation of various azo-dyes in aqueous solutions under visible light irradiation. The effect of transition metals on azo-dye photodegradation has been examined. The nanofiber mat-supported copper–porphyrin and iron–porphyrin complexes are among the most effective photocatalysts for azo-dye degradation. Immobilization of the metalloporphyrins onto the nanofiber mats greatly facilitates the recovery and reuse of the expensive and toxic photocatalysts. Most interestingly, there are no significant degradations of the photocatalytic activities of the recycled photocatalysts. © 2012 Society of Chemical Industry
Co-reporter:Furen Zhang, Chunmei Li, Chenze Qi
Tetrahedron: Asymmetry 2013 Volume 24(Issue 7) pp:380-388
Publication Date(Web):15 April 2013
DOI:10.1016/j.tetasy.2013.02.013
An efficient, solvent-free protocol for the asymmetric aldol reaction between aldehydes and ketones using prolinamides 1–4 as organocatalysts is reported. Catalysts 2–4, in the presence of TFA (the ratio of catalyst and TFA = 1/1.5), proved to be excellent catalysts, giving the aldol products between aromatic aldehydes and ketones with nearly perfect diastereo- and enantioselectivities (up to >99:1 dr and >99% ee). This catalytic system can also be applied in the cross-aldol reaction of isatin with ketones and the Michael reaction between cyclohexane and nitroalkenes. A mechanism is proposed to account for the formation of the major enantiomer in this reaction.Catalyst 1C26H32N4O3[α]D20=+22.0 (c 0.01, CHCl3)Absolute configuration: (Sc, Sc)Sa = axial chirality, Sc = central chiralitySource of chirality: L-prolineCatalyst 2C25H32N4O4S[α]D20=-82.8 (c 0.01, CHCl3)Absolute configuration: (Sc, Sc)Sa = axial chirality, Sc = central chiralitySource of chirality: L-prolineCatalyst 3C34H40N4O3[α]D20=-6.5 (c 0.01, CHCl3)Absolute configuration: (Sa,Sc,Sc)Sa = axial chirality, Sc = central chiralitySource of chirality: L-prolineCatalyst 4C33H40N4O4S[α]D20=-29.9 (c 0.01, CHCl3)Absolute configuration: (Sa,Sc,Sc)Sa = axial chirality, Sc = central chiralitySource of chirality: L-proline
Co-reporter:Chen Wang, Chenze Qi
Tetrahedron 2013 69(26) pp: 5348-5354
Publication Date(Web):
DOI:10.1016/j.tet.2013.04.123
Co-reporter:Lehao Huang, Qian Li, Chen Wang, and Chenze Qi
The Journal of Organic Chemistry 2013 Volume 78(Issue 7) pp:3030-3038
Publication Date(Web):February 20, 2013
DOI:10.1021/jo400017v
A palladium(II)-catalyzed quinolinamide-directed 8-arylation of 1-naphthylamides with aryl iodides is reported. The bidentate directing group (quinolinamide) proved to be crucial for a highly regioselective transformation. In addition, the amide directing group can be easily hydrolyzed under basic conditions to offer a range of 8-aryl-1-naphthylamine derivatives. The theoretical calculations suggest that the C–H arylation reaction proceeds through a sequential C–H activation/oxidative addition pathway.
Co-reporter:Kai Cheng, Sai Hu, Baoli Zhao, Xian-Man Zhang, and Chenze Qi
The Journal of Organic Chemistry 2013 Volume 78(Issue 10) pp:5022-5025
Publication Date(Web):May 8, 2013
DOI:10.1021/jo302791q
Palladium-catalyzed Hiyama-type cross-coupling reactions of various arenesulfinates with organosilanes were achieved in good to excellent yields under aerobic conditions at 70 °C. Fluoride is essential, and tetrabutylammonium fluoride (TBAF) was shown to be the most efficient additive for these cross-coupling reactions. These cross-coupling reactions of the arenesulfinates provide high yields and show wide functional group tolerance, making them attractive alternative transformations to traditional cross-coupling approaches for carbon–carbon bond construction.
Co-reporter:Fujian Liu, Shufeng Zuo, Weiping Kong and Chenze Qi
Green Chemistry 2012 vol. 14(Issue 5) pp:1342-1349
Publication Date(Web):15 Mar 2012
DOI:10.1039/C2GC16562G
Strong acidic ionic liquids functionalized, ordered and stable mesoporous phenol–formaldehyde resins (OMR-ILs) monoliths have been successfully synthesized from the treatment of ordered mesoporous resins (OMR-[HMTA]) using 1,3-propanesultone, followed by ion exchanged using various strong acids. The OMR-[HMTA] samples could be synthesized by the assembly of block copolymer template of F127 with preformed resol, which could be obtained from heating a mixture of phenol and formaldehyde at 70 °C; during curing processes, certain contents of the hexamethyltetramine (HMTA) cross linker were also introduced, after hydrothermal treatment at 200 °C for 20 h, calcination at 360 °C under nitrogen, OMR-[HMTA] samples with opened mesopores were obtained. Characterizations suggest that OMR-ILs have ordered and stable mesospores, high BET surface areas, and strong acid strength. Interestingly, OMR-ILs show much higher catalytic activities and recyclability in the esterification of acetic acid with cyclohexanol, hydration of propylene oxide, Peckmann reaction of resorcinol with ethyl acetoacetate and transesterification of tripalmitin with methanol than those of Amberlyst 15, sulfonic group functional ordered mesoporous silicas and acidic zeolites, which were even comparable with that of H2SO4. The unique features of OMR-ILs such as superior thermal stability, excellent catalytic activities and recyclability, will be potentially important for their applications in industry.
Co-reporter:Fujian Liu, Chun-Lin Liu, Baowei Hu, Wei-Ping Kong, Chen-Ze Qi
Applied Surface Science 2012 Volume 258(Issue 19) pp:7448-7454
Publication Date(Web):15 July 2012
DOI:10.1016/j.apsusc.2012.04.059
Abstract
Mesoporous titanium dioxide with crystalline mesopore walls (M-TiO2-ns) have been successfully synthesized through the self-assembly of poly 4-Vinylpyridine template and tetrabutyl titanate precursor based on their complex bond interaction under high temperature (180 °C) hydrothermal conditions. X-ray diffraction shows that M-TiO2-ns have highly crystalline mesopore walls with anatase phase characters; N2 sorption–desorption isotherms, SEM and TEM images show that M-TiO2-ns have high BET surface areas (85 and 120 m2/g, respectively), large pore volumes (0.32 and 0.34 cm3/g, respectively) and crystalline mesopore walls, which exhibit monolithic morphology with crystal sizes around 3–5 μm. Interestingly, M-TiO2-ns exhibit much higher catalytic activities and good recyclability in both induced reduction of decabromodiphenyl and oxidation of Rhodamine B under UV light than those of nonporous crystalline TiO2 and M-TiO2 templated by hydrocarbon surfactant of F127, which is even comparable with that of commercial P25. Combination of the unique characters such as crystallinity, stable mesostructure, large BET surface areas and superior photo catalytic activities make M-TiO2-ns a kind of potentially important material for removing of organic pollutions in environment through green photo irradiation processes.
Co-reporter:Yiyuan Ding, Kai Cheng, Chenze Qi, Qingbao Song
Tetrahedron Letters 2012 Volume 53(Issue 46) pp:6269-6272
Publication Date(Web):14 November 2012
DOI:10.1016/j.tetlet.2012.09.028
A simple and efficient protocol has been developed for the synthesis of various symmetrical biaryls in good to excellent yields from the homocoupling reactions of arenediazonium salts with ferrous salt in carbon tetrachloride solution under mild reaction conditions. Moreover, the novel homocoupling has been demonstrated to proceed via an electron transfer reaction mechanism.Efficient homocoupling of arenediazonium salts to afford symmetrical biaryls. Proceeded with ferrous salt under mild conditions. Proceeded via an electron transfer reaction mechanism.
Co-reporter:Minfeng Zeng, Xin Zhang, Linjun Shao, Chenze Qi, Xian-Man Zhang
Journal of Organometallic Chemistry 2012 704() pp: 29-37
Publication Date(Web):
DOI:10.1016/j.jorganchem.2012.01.003
Co-reporter:Linjun Shao;Yijun Du;Guiying Xing;Weixi Lv
Monatshefte für Chemie - Chemical Monthly 2012 Volume 143( Issue 8) pp:1199-1203
Publication Date(Web):2012 August
DOI:10.1007/s00706-011-0706-0
A novel polyacrylonitrile hybrid fiber mat supported solid acid catalyst was prepared by electrospinning, and its catalytic activities were carefully investigated through acetalization reactions. The results showed that this hybrid fiber mat exhibits high activity for the reactions, with average yields over 95%. Besides having catalytic activities similar to the solid acid, the heterogeneous solid acid/polyacrylonitrile mat can be reused in six runs without significant loss of catalytic activities. The large size of the hybrid fiber mat greatly facilitates recovery of the catalyst from the reaction mixture. The high and stable catalytic activities of the hybrid fiber mat hold great potential for green chemical processes and preparation of membrane reactors in the future.
Co-reporter:Minfeng Zeng, Yijun Du, Chenze Qi, Shufeng Zuo, Xiudong Li, Linjun Shao and Xian-Man Zhang
Green Chemistry 2011 vol. 13(Issue 2) pp:350-356
Publication Date(Web):24 Dec 2010
DOI:10.1039/C0GC00780C
An efficient and recyclable ligand-free heterogeneous catalyst has been prepared by the immobilization of palladium onto ground pearl shell powders (Pd/shell powders, Pd/SP). The catalytic activity and recyclability of the prepared Pd/SP along with the charcoal and calcium carbonate supported palladium (Pd/C and Pd/CaCO3) catalysts have been evaluated using the reductive homocoupling of aromatic halides. Pd/SP not only has higher catalytic activity, but also exhibits much stronger stability than Pd/C and Pd/CaCO3. The remarkable Pd/SP stability has been attributed to the chelation of palladium species with the surface chitin and protein molecules of the supported pearl shell powders. The X-ray photoelectron spectroscopy (XPS) studies show that the reductive Pd0 species can be regenerated in situ from the oxidative Pd2+ species for the Pd/SP catalyzed reductive homocoupling of aromatic halides in ethanol/DMSO solution, suggesting that the heterogeneous and homogeneous palladium catalysis proceeds through a similar Pd0/Pd2+ cycle catalytic mechanism.
Co-reporter:Xuezheng Liang, Yuxiao Cheng, Chenze Qi
Solid State Sciences 2011 Volume 13(Issue 9) pp:1820-1824
Publication Date(Web):September 2011
DOI:10.1016/j.solidstatesciences.2011.06.025
Novel polypyrrole based acid catalyst has been synthesized through the neutralization reaction of polypyrrole and sulfuric acid. The polypyrrole based acid owned the acidity as high as 6.0 mmol/g, which was much higher than that of the traditional solid acids such as Nafion and Amberlyst-15 (0.8 mmol/g). The catalytic activities of the novel solid acid were investigated through the acetalization. The results showed that the novel solid acid held high activities for the reactions. Furthermore, the recycled activities of the catalyst indicated that the solid acid owned high stability during the catalytic process and little acid sites dropped from polypyrrole. The high acidity and stability made the novel polypyrrole based acid hold great potential for the green chemical processes.Highlights► Novel Polypyrrole based strong acid catalyst has been synthesized. ► The solid acid owned the acidity as high as 6.0 mmol/g ► The novel solid acid held high activities for the reactions.
Co-reporter:Linjun Shao;Jie Liu;Yuhang Ye;Xian-Man Zhang ;Chenze Qi
Applied Organometallic Chemistry 2011 Volume 25( Issue 9) pp:699-703
Publication Date(Web):
DOI:10.1002/aoc.1830
Abstract
A novel palladium catalyst immobilized on polyacrylonitrile fiber mats (Pd/PAN) was prepared by electrospinning. The catalytic activity and recyclability of the microwave-assisted Pd/PAN fiber mats were examined for the Mizoroki–Heck cross-coupling of aryl iodides with three different acrylates in aqueous solution. The morphology of the prepared Pd/PAN fiber mats was characterized by scanning electron microscopy. The large size of the PAN fiber mat-supported palladium catalyst enables much easier separation from the reaction mixture by simple filtration. Density functional theory calculation indicates that the chelation energy of palladium chloride (PdCl2) with propionitrile (model of PAN) is considerable smaller than that of PdCl2 with water, suggesting that the stability and reactivity of the Pd/PAN fiber mats catalyst could be improved through the surface derivatization with polar functional groups. Copyright © 2011 John Wiley & Sons, Ltd.
Co-reporter:Xuezheng Liang;Chunqing Li;Chenze Qi
Journal of Materials Science 2011 Volume 46( Issue 16) pp:5345-5349
Publication Date(Web):2011 August
DOI:10.1007/s10853-011-5472-1
The novel carbon-based strong acid catalyst has been synthesized through the simple heat treatment of 2-hydroxyethylsulfonic acid and starch. The novel solid acid owned the high acidity of 2.6 mmol/g, much higher than that of the traditional solid acids such as Nafion and Amberlyst-15 (0.8 mmol/g). The catalytic activities of the novel carbon-based acid were investigated through the acetalization reactions. The results showed that the novel solid acid was very efficient for the reactions with high yields. The high acidity and catalytic activities made the novel solid acid hold great potential for the green chemical processes.
Co-reporter:Kai Cheng, Chen Wang, Yiyuan Ding, Qingbao Song, Chenze Qi, and Xian-Man Zhang
The Journal of Organic Chemistry 2011 Volume 76(Issue 22) pp:9261-9268
Publication Date(Web):October 13, 2011
DOI:10.1021/jo201437j
Palladium acetate [Pd(OAc)2]-catalyzed Hiyama cross-coupling of arenediazonium salts with organosilanes was found to generate biaryl products in high yields in alcoholic solutions. The simple and efficient protocol does not require any bases, ligands, or air/moisture. The transformation can tolerate either electron-donating or electron-withdrawing functional groups. Theoretical studies show that the transmetalation is the rate-limiting step for the cross-coupling reaction and both acetate and tetrafluoroborate anions may be involved in the direct reaction with the silicon atom.
Co-reporter:Yong-Miao Shen;Yi-Jun Du;Min-Feng Zeng;Duo Zhi;Sheng-Xian Zhao;Lin-Mei Rong;Shao-Qin Lv;Lin Du
Applied Organometallic Chemistry 2010 Volume 24( Issue 9) pp:631-635
Publication Date(Web):
DOI:10.1002/aoc.1657
Abstract
A novel palladium catalyst supported on shell powder has been prepared, and its application to the Heck reaction of aryl iodides with olefins has been reported. The results showed that the novel catalyst had extremely high activities for the reactions with the average yield over 90%. Also, this catalyst showed excellent stability in Heck reactions, being reused three times. The catalyst was characterized by X-ray powder diffraction and field-emission scanned electron microscopy images, and the energy dispersive X-ray analyzer. Copyright © 2010 John Wiley & Sons, Ltd.
Co-reporter:Huiquan Xiao;Yingxue Guo;Xuezheng Liang
Monatshefte für Chemie - Chemical Monthly 2010 Volume 141( Issue 8) pp:929-932
Publication Date(Web):2010 August
DOI:10.1007/s00706-010-0332-2
A novel carbon-based strong acid catalyst was synthesized through the one-step hydrothermal carbonization of furaldehyde and p-toluenesulfonic acid (PTSA) in aqueous solution at 180 °C for only 4 h. The novel carbon-based solid acid possessed high acidity, and the catalytic activities were investigated by esterification and oxathioketalization. The results showed that the novel catalyst demonstrated much greater activity than the traditional solid acids and was comparable to sulfuric acid. The one-step method provides an efficient procedure for the synthesis of various functionalized carbons by one-step hydrothermal carbonization.
Co-reporter:Zeng Minfeng, Sun Xudong, Lu Cuiyun, Li Zhuoxin, Wang Baoyi, Qi Chenze
Radiation Physics and Chemistry (June 2012) Volume 81(Issue 6) pp:628-631
Publication Date(Web):1 June 2012
DOI:10.1016/j.radphyschem.2012.02.006
Positron age-momentum correlation (AMOC) spectroscopy is applied to study the associations between the momentum distributions and positron annihilation in the toughened CE networks. The Doppler profile of the positron annihilation process is much broader for the toughened CE than pure CE network. This is due to positron trapping on high polar groups of the added elastomers or nano-CaCO3 and annihilation with the electrons of high momenta. The broadening momentum distribution of ortho-positronium annihilation process indicates that the pick-off annihilation process is strongly influenced by the added high polar elastomers or nano-CaCO3. The potential of AMOC spectroscopy for free volume analysis in polymer blends was demonstrated.Highlights► AMOC can be applied to the analyses of interfacial properties in polymer blends. ► The Doppler profile is much broader for the toughened CE than pure CE network. ► Positron trapping on high polar groups of the modifiers is demonstrated by AMOC.
Co-reporter:Chunmei Li, Xuezheng Liang, Furen Zhang, Chenze Qi
Catalysis Communications (5 March 2015) Volume 62() pp:6-9
Publication Date(Web):5 March 2015
DOI:10.1016/j.catcom.2014.12.026
•A novel, mild, and environ friendly, one pot synthetic protocol was developed.•The carbonaceous material is first used in domino reaction of nitrostyrene.•The catalyst is reusable and gives high conversions.•The domino reaction follows the acid-catalyzed mechanism.An efficient, high yielding method has been developed for the synthesis of diversity tetrahydro-4H-indol-4-one derivatives via a three component, one pot domino reaction from cyclohexane-1,3-diones, amines and nitrostyrenes using carbon functionalized with sulfonic acid group carbonaceous material as catalyst for the first time. The reaction was carried out in water, affording good to excellent yields in short time. The advantages of atom and step economy, green, and scope make this reaction a powerful tool for assembling heterocyclic scaffolds of general chemical and biomedical interest.Download high-res image (169KB)Download full-size image
Co-reporter:Hailong Shi, Yan Li, Xiaorong Ren, Yaohong Zhang, Zhen Yang, Chenze Qi
Biochemical and Biophysical Research Communications (29 April 2017) Volume 486(Issue 2) pp:
Publication Date(Web):29 April 2017
DOI:10.1016/j.bbrc.2017.03.034
•Electrophilic molecule QNZ-A selectively kills A549 cancer cells by ROS-promoting.•The cytotoxic mechanism relies on ROS-dependent G2/M-phase arrest and apoptosis.•QNZ-A up regulates mRNA and protein levels of p53 and p21 in a ROS-dependent way.•QNZ-A induces ROS-dependent G2/M arrest through Cdc25C/cyclin B1/Cdk1 pathway.•Michael acceptor-dependent prooxidant anticancer strategy is supported.6-amino-4-(4-phenoxyphenylethylamino)quinazoline (QNZ) is an excellent quinazoline-containing NF-κB inhibitor also acting as a novel anticancer agent. Considering both the medicinal significance of quinazoline scaffold and the tunable functionality of Michael acceptor-centric pharmacophores in the electrophilicity-based prooxidant strategy, we designed a novel QNZ-inspired electrophilic molecule QNZ-A by introducing a Michael acceptor unit at position-6 of quinazoline ring in QNZ. Our results identified QNZ-A as a promising selective cytotoxic agent against A549 cells. QNZ-A, by virtue of its Michael acceptor unit, induced reactive oxygen species (ROS) accumulation associated with collapse of the redox buffering system in A549 cells. This caused up-regulation of p53-inducible p21 and down-regulation of redox sensitive Cdc25C along with Cyclin B1/Cdk1, leading to a G2/M cell cycle arrest and final cell apoptosis. By contrast, QNZ-B, a reduction product of QNZ-A lacking the Michael acceptor unit failed to induce ROS generation and all these cell cycle-related events. In conclusion, this work provided a successful example of designing QNZ-directed anticancer agent by a ROS-promoting strategy and identified QNZ-A as a selective anticancer agent against A549 cells through G2/M cell cycle arrest and apoptosis via a ROS-dependent mechanism.
Co-reporter:Shufeng Zuo, Chenze Qi
Catalysis Communications (15 November 2011) Volume 15(Issue 1) pp:74-77
Publication Date(Web):15 November 2011
DOI:10.1016/j.catcom.2011.08.021
Palladium and cerium oxide promoted Co/Al2O3 catalysts were prepared and used for oxidation of benzene. Influence of Pd, Ce and Co/Ce molar ratios on the properties and catalytic performance was investigated. The results indicated that addition of palladium and cerium oxide could provide active oxygen species to cobalt oxide and make Co3O4 particles better dispersed on Al2O3, thus enhancing oxidation ability of the catalyst. High catalyst activity is mainly attributed to better dispersed Co3O4 on Al2O3, smaller Co3O4 crystallites and larger CeO2 crystallites which can strengthen the interaction among PdO, CeO2 and Co3O4.Highlights► The Co/Al2O¬3 catalyst with Pd and Ce addition exhibits high activity. ► Pd/Co-Ce/Al2O3 with a Co/Ce mole ratio of 6 owns the highest activity. ► High activity is attributed to better dispersed Co3O4 and larger CeO2 crystallites.
Co-reporter:Kai Cheng, Guofang Wang, Mengting Meng and Chenze Qi
Inorganic Chemistry Frontiers 2017 - vol. 4(Issue 3) pp:NaN403-403
Publication Date(Web):2016/12/13
DOI:10.1039/C6QO00634E
The Pd(TFA)2-catalyzed denitrogenative addition proceeded with selective C–N bond cleavage of arylhydrazines with nitriles in the presence of DABCO and HFBA under air at room temperature. Aryl ketones could be easily synthesized via the hydrolysis of the ketimine moiety generated in situ without the need for additional water.
Co-reporter:Fujian Liu, Bojie Li, Chen Liu, Weiping Kong, Xianfeng Yi, Anmin Zheng and Chenze Qi
Catalysis Science & Technology (2011-Present) 2016 - vol. 6(Issue 9) pp:NaN3007-3007
Publication Date(Web):2015/11/19
DOI:10.1039/C5CY01226K
N rich porous carbon based solid acids (NPC-[CxN][X]) have been successfully synthesized by treatment of N rich porous carbon (NPC) with various quaternary ammoniation reagents such as iodomethane, 1,3-propane sultone, and 1,4-butanesultone, and ion exchange with various strong acids such as HSO3CF3, H2SO4, H3PW12O40, HBF4etc. The NPC support was synthesized by carbonization of KOH-activated polypyrrole without using additional templates. Various characterizations showed that NPC-[CxN][X] possesses abundant nanopores, large Brunauer–Emmett–Teller surface areas, good stability, and strong and controllable acid sites with Brønsted characteristics. The immobilized acidic groups were homogeneously dispersed into NPC-[CxN][X]. Notably, NPC-[CxN][X] acted as efficient, reusable and generalized solid acids, which showed excellent activity in various acid-catalyzed reactions such as esterification and transesterification in the synthesis of biodiesel, dehydration of fructose into 5-hydroxymethylfurfural, depolymerization of crystalline cellulose into sugars, and condensation of phenol with acetone in the synthesis of bisphenol A, much higher than that of various solid acids such as Amberlyst 15, H-ZSM-5, H-USY, and sulfonic group functionalized ordered mesoporous silicas. The preparation of NPC-[CxN][X] leads to the development of porous carbon based solid acids with controllable structural characteristics and excellent catalytic activity.
Co-reporter:Fujian Liu, Shufeng Zuo, Xiaodan Xia, Jing Sun, Yongcun Zou, Liang Wang, Chunguang Li and Chenze Qi
Journal of Materials Chemistry A 2013 - vol. 1(Issue 12) pp:NaN4096-4096
Publication Date(Web):2013/01/21
DOI:10.1039/C3TA01505J
We report here a generalized synthesis of various crystalline mesoporous metal oxides including CeO2, Cr2O3, Fe2O3, SnO2, Ce0.5Zr0.5O2, TiO2, Al2O3 and ZrO2 from the self-assembly of a basic poly 4-vinylpyridine (P4VP) template with various metal precursors based on their strong acid–base interaction under high temperature (180 °C) hydrothermal conditions. Using the typically crystalline mesoporous metal oxide of CeO2, after removing the template by calcination at 550 °C and loading with various transition metal oxides such as MnOx, various transition metal oxide functionalized crystalline mesoporous CeO2 (MnOx/P4VP–CeO2) were obtained. X-ray diffraction (XRD) patterns show that the resulting mesoporous metal oxides exhibit a high degree of crystallinity, and the transition metal oxides active sites have been successfully loaded into these samples. N2 sorption–desorption isotherms, SEM images show that the resulting crystalline mesoporous metal oxides, such as CeO2, have a large BET surface area (94 m2 g−1) and abundant mesopores, which exhibit monolithic morphology with crystal sizes ranging from 5 to 15 μm, giving a uniform pore size centered at 5 nm. XPS spectra show that the active sites such as MnOx exhibit the phases of MnO2 and Mn2O3 in P4VP–CeO2. H2-TPR curves show that MnOx/P4VP–CeO2 exhibits decreased reductive temperatures of both active sites of the MnOx and P4VP–CeO2 supporter when compared with the samples reported previously. More importantly, MnOx/P4VP–CeO2 exhibits much better catalytic activities and good recyclability for catalyzing the oxidation of benzene than that of MnOx loaded commercially crystalline CeO2, which will be very important for their wide applications for VOCs removal in industry.
Co-reporter:Furen Zhang, Chunmei Li, Chen Wang and Chenze Qi
Organic & Biomolecular Chemistry 2015 - vol. 13(Issue 17) pp:NaN5029-5029
Publication Date(Web):2015/03/19
DOI:10.1039/C5OB00129C
A facile and efficient approach has been established for the synthesis of benzoindole and naphthofuran derivatives via the metal-free cyclization reaction of nitroolefins with naphthylamines/naphthols. Various substituted benzoindoles and naphthofurans are obtained in good to excellent yields. Moreover, the ability to recycle the carbonaceous material makes this method quite cost-effective and environmentally benign compared to traditional acid-catalyzed methods. Theoretical studies indicated that the reaction between naphthylamine and nitroolefin catalyzed by this solid acid was thermodynamically controlled at 60 °C, resulting in the formation of the benzoindoles.
Co-reporter:Fujian Liu, Ranjan K. Kamat, Iman Noshadi, Daniel Peck, Richard S. Parnas, Anmin Zheng, Chenze Qi and Yao Lin
Chemical Communications 2013 - vol. 49(Issue 76) pp:NaN8458-8458
Publication Date(Web):2013/07/31
DOI:10.1039/C3CC44703K
The acidic ionic liquid (IL) functionalized polymer (PDVB–SO3H–[C3vim][SO3CF3]) possesses abundant nanoporous structures, strong acid strength and unique capability for deconstruction of crystalline cellulose into sugars in ILs. The polymer shows much improved catalytic activities in comparison with mineral acids, homogeneous acidic ionic liquids and the acidic resins such as Amberlyst 15. The enhanced catalytic activity found in the polymer is attributed to synergistic effects between the strongly acidic group and the ILs grafted onto the polymer, which by itself is capable of breaking down the crystalline structures of cellulose. This study may help develop cost-effective and green routes for conversion of biomass to fuels.
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