Feng Wang

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Organization: Dalian Institute of Chemical Physics

Department: State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy

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TOPICS

Polymer

Stimuli Responsive Polymers Stimuli Responsive Polymers Photo Responsive Polymers Temperature Responsive Polymers

Organic Chemistry

Pyridine Ligands C-H Activation Liquid Crystal

Chemicals
References

Promoting Lignin Depolymerization and Restraining the Condensation via an Oxidation−Hydrogenation Strategy

Co-reporter:Chaofeng Zhang, Hongji Li, Jianmin Lu, Xiaochen Zhang, Katherine E. MacArthur, Marc Heggen, and Feng Wang

ACS Catalysis May 5, 2017 Volume 7(Issue 5) pp:3419-3419

Publication Date(Web):April 6, 2017

DOI:10.1021/acscatal.7b00148

For lignin valorization, simultaneously achieving the efficient cleavage of ether bonds and restraining the condensation of the formed fragments represents a challenge thus far. Herein, we report a two-step oxidation–hydrogenation strategy to achieve this goal. In the oxidation step, the O2/NaNO2/DDQ/NHPI system selectively oxidizes CαH–OH to Cα═O within the β-O-4 structure. In the subsequent hydrogenation step, the α-O-4 and the preoxidized β-O-4 structures are further hydrogenated over a NiMo sulfide catalyst, leading to the cleavage of Cβ–OPh and Cα–OPh bonds. Besides the transformation of lignin model compounds, the yield of phenolic monomers from birch wood is up to 32% by using this two-step strategy. The preoxidation of CαH–OH to Cα═O not only weakens the Cβ–OPh ether bond but also avoids the condensation reactions caused by the presence of Cα+ from dehydroxylation of CαH–OH. Furthermore, the NiMo sulfide prefers to catalyze the hydrogenative cleavage of the Cβ–OPh bond connecting with a Cα═O rather than catalyze the hydrogenation of Cα═O back to the original CαH–OH, which further ensures and utilizes the advantages of preoxidation.Keywords: lignin; lignin fragments’ condensation; NaNO2/DDQ/NHPI; NiMo sulfide; oxidation−hydrogenation; phenolic monomer;

Visible Light Gold Nanocluster Photocatalyst: Selective Aerobic Oxidation of Amines to Imines

Co-reporter:Haijun Chen, Chao Liu, Min Wang, Chaofeng Zhang, Nengchao Luo, Yehong Wang, Hadi Abroshan, Gao Li, and Feng Wang

ACS Catalysis May 5, 2017 Volume 7(Issue 5) pp:3632-3632

Publication Date(Web):April 10, 2017

DOI:10.1021/acscatal.6b03509

This work demonstrates the synthesis of an efficient photocatalyst, Au25(PPh3)10Cl2(SC3H6SiO3)5/TiO2, for selective oxidation of amines to imines. The photocatalyst is prepared via hydrolysis of Au25(PPh3)10Cl2[(SC3H6Si(OC2H5)3]5 nanoclusters in the presence of TiO2 support. The gold nanoclusters exhibit good photocatalytic activity using visible light and under mild thermal conditions for the selective oxidation with molecular oxygen (O2). The turnover frequency (TOF) of 4-methylbenzylamine oxidation is found to be 1522 h–1, which is considerably higher than that conventional gold catalysts. The gold nanoclusters present good recyclability and stability for the oxidation of a wide range of amines. The superior activity of the photocatalyst is associated with its unique electronic structure and framework. The catalytically active sites are deemed to be the exposed gold atoms upon detaching protecting ligands: i.e., PPh3. The Hammett parameter suggests that the photocatalytic process involves the formation of carbocation intermediate species. Further, Au–H species were confirmed by TEMPO (2,2,6,6-tetramethylpiperidinyloxy) as a trapping agent.Keywords: Au25; benzylamine oxidation; gold nanoclusters; photocatalysis; selective organic transformation;

Yin and Yang Dual Characters of CuOx Clusters for C–C Bond Oxidation Driven by Visible Light

Co-reporter:Tingting Hou, Nengchao Luo, Hongji Li, Marc Heggen, Jianmin Lu, Yehong Wang, and Feng Wang

ACS Catalysis June 2, 2017 Volume 7(Issue 6) pp:3850-3850

Publication Date(Web):April 24, 2017

DOI:10.1021/acscatal.7b00629

Selective cleavage of C–C bonds is pursued as a useful chemical transformation method in biomass utilization. Herein, we report a hybrid CuOx/ceria/anatase nanotube catalyst in the selective oxidation of C–C bonds under visible light irradiation. Using the lignin β-1 model as a substrate offers 96% yields of benzaldehydes. Characterization results by high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and energy-dispersive X-ray spectroscopy element (EDX) mapping reveal that CuOx clusters are highly dispersed on the exposed anatase surface as well as on the nanosized ceria domains. In-depth investigations by Raman and ultraviolet visible diffuse reflectance spectra (UV−vis DRS), together with density functional theory (DFT) calculations, further verify that the CuOx clusters present on the ceria domains increase the concentration of surface defects (Ce3+ ions and oxygen vacancies) and accordingly improve the photocatalytic activity (Yang character); the CuOx clusters decorating on anatase suppress the side reaction (oxy-dehydrogenation without C–C bond cleavage) because of an upward shift in the valence band (VB) edge of anatase (Yin character). Mechanism investigation indicates hydrogen abstraction from β-carbon by photogenerated holes is a vital step in the conversion.Keywords: benzaldehyde; ceria; copper; C−C bond; heterogeneous catalysis; titania; visible light;

Visible-Light-Driven Self-Hydrogen Transfer Hydrogenolysis of Lignin Models and Extracts into Phenolic Products

Co-reporter:Nengchao Luo, Min Wang, Hongji Li, Jian Zhang, Tingting Hou, Haijun Chen, Xiaochen Zhang, Jianmin Lu, and Feng Wang

ACS Catalysis July 7, 2017 Volume 7(Issue 7) pp:4571-4571

Publication Date(Web):May 31, 2017

DOI:10.1021/acscatal.7b01043

Obtaining high selectivity of aromatic monomers from renewable lignin has been extensively pursued but is still unsuccessful, hampered by the need to efficiently cleave C–O/C–C bonds and inhibit lignin proliferation reactions. Herein, we report a transfer hydrogenolysis protocol using a heterogeneous ZnIn2S4 catalyst driven by visible light. In this process, alcoholic groups (CαH–OH) of lignin act as hydrogen donors. Proliferation of phenolic products to dark substances is suppressed under visible light illumination at low temperature (below 50 °C); formation of a light and transparent reaction solution allows visible light to be absorbed by the catalyst. With this strategy, 71–91% yields of phenols in the conversion of lignin β-O-4 models and a 10% yield of p-hydroxyl acetophenone derivatives from organosolv lignin are achieved. Mechanistic studies reveal that CαH–OH groups of lignin β-O-4 linkage are initially dehydrogenated on ZnIn2S4 to form a “hydrogen pool”, and the adjacent Cβ–O bond is subsequently hydrogenolytically cleaved to two monomers by the “hydrogen pool”. Thus, the dehydrogenation and hydrogenolysis reaction are integrated in one-pot with lignin itself as a hydrogen donor. This study shows a promising way of supplying phenolic compounds by taking advantages of both renewable biomass feedstocks and photoenergy.Keywords: heterogeneous catalysis; lignin; transfer hydrogenation; visible light; ZnIn2S4;

Conversion of Isobutene and Formaldehyde to Diol using Praseodymium-Doped CeO2 Catalyst

Co-reporter:Zhixin Zhang, Yehong Wang, Jianmin Lu, Chaofeng Zhang, Min Wang, Mingrun Li, Xuebin Liu, and Feng Wang

ACS Catalysis December 2, 2016 Volume 6(Issue 12) pp:8248-8248

Publication Date(Web):November 1, 2016

DOI:10.1021/acscatal.6b02134

Conversion of low-carbon olefins to higher alcohols or olefins via the formation of C–C bonds is an increasingly important topic. We herein report an example of converting isobutene and formaldehyde (38 wt % aqueous solution) to 3-methyl-1,3-butanediol (MBD), a precursor for isoprene. The reaction occurs through a Prins condensation–hydrolysis reaction over a praseodymium (Pr)-doped CeO2 catalyst. The best MBD yield (70%) is achieved over the Pr-doped CeO2 catalyst. Catalyst characterizations with high-angle annular dark field transmission electron microscopy (HAADF-TEM), pyridine adsorption infrared (IR) and Raman spectroscopy, and density functional theory (DFT) calculations show that the doped Pr is uniformly and highly dispersed in the CeO2 crystalline phase. In addition, the Pr doping creates more oxygen vacancy sites on CeO2 and thus enhances the Lewis acidity of the catalyst, which is responsible for the catalytic performance of the Pr-CeO2 catalyst.Keywords: CeO2; hydrolysis; Lewis acid; metal-doped; oxygen vacancy; Prins condensation;

Photocatalytic coupling of amines to imidazoles using a Mo–ZnIn2S4 catalyst

Co-reporter:Min Wang;Lihua Li;Jianmin Lu;Nengchao Luo;Xiaochen Zhang

Green Chemistry (1999-Present) 2017 vol. 19(Issue 21) pp:5172-5177

Publication Date(Web):2017/10/30

DOI:10.1039/C7GC01728F

Substituted imidazoles are traditionally synthesized by co-condensation of multiple feedstocks. Herein, we report a new route for the synthesis of substituted imidazoles via photocyclization of readily available amines at room temperature. The reaction is achieved by the visible-light-induced C–C/C–N bond coupling and subsequent dehydrogenation reaction over Mo–ZnIn2S4 as a heterogeneous photocatalyst. A wide range of amines were converted into the corresponding tri- and tetra-substituted imidazoles with up to 96% total yields. The simplicity, high efficiency and mild condition merits of this new reaction will enable it to be useful in synthetic transformations.

Acid promoted C–C bond oxidative cleavage of β-O-4 and β-1 lignin models to esters over a copper catalyst

Co-reporter:M. Wang;L. H. Li;J. M. Lu;H. J. Li;X. C. Zhang;H. F. Liu;N. C. Luo;F. Wang

Green Chemistry (1999-Present) 2017 vol. 19(Issue 3) pp:702-706

Publication Date(Web):2017/02/06

DOI:10.1039/C6GC02970A

Depolymerisation of lignin to aromatics is a challenging task. We herein report that a Cu(OAc)2/BF3·OEt2 catalyst is effective in simultaneously cleaving C–C bonds in β-1 and β-O-4 ketones, yielding esters and phenols. In-depth studies show that C–H bond activation is the rate determining step for C–C bond cleavage. BF3·OEt2 promotes the reaction via activating the β-C–H bond. This study offers the potential to obtain aromatic esters from lignin.

Sell a dummy: Adjacent functional group modification strategy for the catalytic cleavage of lignin β–O–4 linkage

Co-reporter:Chaofeng Zhang, Feng Wang

Chinese Journal of Catalysis 2017 Volume 38, Issue 7(Volume 38, Issue 7) pp:

Publication Date(Web):1 July 2017

DOI:10.1016/S1872-2067(17)62858-4

This perspective highlights recent progress on lignin β-O-4 conversion, which focuses on the combinatorial strategies leading to lignin β-O-4 cleavage beginning with adjacent fmunctional group modification, and provides insight into the challenges unexplored in this area.Download high-res image (222KB)Download full-size image

Peculiar hydrogenation reactivity of Ni–Niδ+ clusters stabilized by ceria in reducing nitrobenzene to azoxybenzene

Co-reporter:Tingting Hou, Yehong Wang, Jian Zhang, Mingrun Li, Jianmin Lu, Marc Heggen, Carsten Sievers, Feng Wang

Journal of Catalysis 2017 Volume 353(Volume 353) pp:

Publication Date(Web):1 September 2017

DOI:10.1016/j.jcat.2017.07.004

•Ni and Niδ+ coexist on ceria even after reduction under H2 at 500 °C due to the strong electronic metal–support interactions.•The presence of Niδ+ could weaken the further hydrogenation of azoxybenzene to aniline over Ni/ceria.•Azoxybenzene was obtained over Ni–Niδ+/ceria with 92% selectivity during nitrobenzene reduction.In many catalytic processes, metastable reaction intermediates are more valuable and desirable than final products. Here, we report Ni–Niδ+ clusters on ceria where the extent of reduction of nickel oxide/ceria in H2 has been optimized. This catalyst shows high selectivity in reducing nitrobenzene to azoxybenzene, the latter usually being metastable. Due to strong electronic metal–support interactions between Ni and ceria, mixed Ni–Niδ+ clusters are formed on ceria even after reduction at 500 °C in hydrogen. The Ni–Niδ+ clusters are highly dispersed on ceria, as observed by high-angle annular dark-field scanning–transmission electron microscopy and energy-dispersive X-ray spectroscopy element mapping. This structural uniqueness is clearly reflected in the inhibition of azoxybenzene hydrogenation to aniline, and therefore the catalyst shows high azoxybenzene selectivity (92%). In comparison, the Ni metal catalyst mostly gives aniline and the NiO catalyst has low activity. This study shows how to steer catalytic reactions toward metastable intermediate products by tuning the extent of reduction of metal oxides deposited on reducible oxides.Download high-res image (58KB)Download full-size image

Life cycle assessment of primary energy demand and greenhouse gas (GHG) emissions of four propylene production pathways in China

Co-reporter:Zhitong Zhao, Yong Liu, Feng Wang, Xuekuan Li, Shuping Deng, Jie Xu, Wei Wei, Feng Wang

Journal of Cleaner Production 2017 Volume 163(Volume 163) pp:

Publication Date(Web):1 October 2017

DOI:10.1016/j.jclepro.2015.12.099

•This paper is based upon a life cycle assessment of energy demand and greenhouse gas emissions of the propylene production.•Four propylene routes including catalytic cracking, stream-cracking, coal-to-olefins and coal-to-propylene were reviewed.•Sensitivity analyses of production scale and feedstock ration for the stream-cracking route were performed.•A quantified life cycle comparison with and without rectisol was performed.Life cycle primary energy demand (PED) and greenhouse gas (GHG) emissions for the production of propylene in China (year 2013) have been carried out by considering several propylene production routes into account, such as catalytic cracking (CC), stream cracking (SC), coal-to-olefins (CTO) and coal-to-propylene (CTP), which cover the entire life cycle including: extraction and transportation of raw resources, preparation of feedstock, and production parts of propylene. The results show that the coal-based propylene pathway represents more PED and GHG emissions than the petroleum-based propylene pathway. The propylene production via CC route has the minimal PED, whereas CTO and CTP routes consume about 2.60 and 2.04 times energy of CC. Life cycle GHG emissions via four pathways are 1.60, 2.06, 12.16, 9.23 tCO2 eq/t propylene, respectively. The coal gasification process plays a dominant contribution to GHG emissions via the coal-based propylene pathway and extraction process contributed the most via petroleum-based propylene pathway, which are the key factors for reducing the GHG emissions of life cycle of propylene. Adopting rectisol process of coal gasification prove effective, which can reduce 32.39% and 26.14% life cycle GHG emissions despite increase about 3% energy. Meanwhile, it is also effective to reduce GHG emissions by enlarging scale of steam crackers.

Ru/ceria-catalyzed direct formylation of amines and CO to produce formamides

Co-reporter:Yehong Wang;Jian Zhang;Haijun Chen;Zhixin Zhang;Chaofeng Zhang;Mingrun Li

Green Chemistry (1999-Present) 2017 vol. 19(Issue 1) pp:88-92

Publication Date(Web):2017/01/03

DOI:10.1039/C6GC02603F

We herein report a new strategy of directly converting amines and CO to formamides with 100% atom utilization efficiency. It is suitable for up to 25 amine substrates with no additives. Ru/ceria is found to be an excellent catalyst for this reaction due the efficient co-activation of CO and amine on Ru species.

Two-Step, Catalytic C–C Bond Oxidative Cleavage Process Converts Lignin Models and Extracts to Aromatic Acids

Co-reporter:Min Wang, Jianmin Lu, Xiaochen Zhang, Lihua Li, Hongji Li, Nengchao Luo, and Feng Wang

ACS Catalysis 2016 Volume 6(Issue 9) pp:6086

Publication Date(Web):August 10, 2016

DOI:10.1021/acscatal.6b02049

We herein report a two-step strategy for oxidative cleavage of lignin C–C bond to aromatic acids and phenols with molecular oxygen as oxidant. In the first step, lignin β-O-4 alcohol was oxidized to β-O-4 ketone over a VOSO4/TEMPO [(2,2,6,6-tetramethylpiperidin-1-yl)oxyl)] catalyst. In the second step, the C–C bond of β-O-4 linkages was selectively cleaved to acids and phenols by oxidation over a Cu/1,10-phenanthroline catalyst. Computational investigations suggested a copper-oxo-bridged dimer was the catalytically active site for hydrogen-abstraction from Cβ–H bond, which was the rate-determining step for the C–C bond cleavage.Keywords: biomass; copper; C−C cleavage; lignin; oxidation

Photocatalytic Oxidation–Hydrogenolysis of Lignin β-O-4 Models via a Dual Light Wavelength Switching Strategy

Co-reporter:Nengchao Luo, Min Wang, Hongji Li, Jian Zhang, Huifang Liu, and Feng Wang

ACS Catalysis 2016 Volume 6(Issue 11) pp:7716

Publication Date(Web):October 6, 2016

DOI:10.1021/acscatal.6b02212

One of the challenges of depolymerizing lignin to valuable aromatics lies in the selective cleavage of the abundant C–O bonds of β-O-4 linkages. Herein we report a photocatalytic oxidation–hydrogenolysis tandem method for cleaving C–O bonds of β-O-4 alcohols. The Pd/ZnIn2S4 catalyst is used in the aerobic oxidation of α-C–OH of β-O-4 alcohols to α-C═O with 455 nm light, and then a TiO2–NaOAc system is employed for cleaving C–O bonds neighboring the α-C═O bonds through a hydrogenolysis reaction by switching to 365 nm light. Interestingly, the oxidation–hydrogenolysis tandem reaction can be conducted in one pot to offer ketones and phenols (up to 90% selectivity) via a dual light wavelength switching (DLWS) strategy. EPR and metal loading experiments elucidate that Ti3+ in TiO2 is formed in situ and is responsible for the photocatalytic hydrogenolysis through electron transfer from Ti3+ to the β-O-4 ketones.Keywords: dual light wavelength switching; lignin; oxidation−hydrogenolysis; photocatalysis; Ti3+

β-O-4 Bond Cleavage Mechanism for Lignin Model Compounds over Pd Catalysts Identified by Combination of First-Principles Calculations and Experiments

Co-reporter:Jianmin Lu, Min Wang, Xiaochen Zhang, Andreas Heyden, and Feng Wang

ACS Catalysis 2016 Volume 6(Issue 8) pp:5589

Publication Date(Web):July 20, 2016

DOI:10.1021/acscatal.6b00502

Lignin in lignocellulosic biomass is the only renewable source for aromatic compounds, and effective valorization of lignin remains a significant challenge in biomass conversion processes. We have performed density functional theory calculations and experiments to investigate the cleavage mechanism of the C–O ether bond in the lignin model compound 2-phenoxy-1-phenylethanol with a β-O-4 linkage over a Pd(111) catalyst surface model. We propose the favorable reaction pathway to proceed as follows: the dilignol reactant gets dehydrogenated first on the α-carbon and then on the −OH group to generate its corresponding ketone 2-phenoxy-1-phenylethanone; the ketone continues to get dehydrogenated on the β-carbon by first a equilibrated keto–enol tautomerization to its enol form and then −OH dehydrogenation; the C–O ether bond cleavage happens afterward, leading to one-aromatic-ring surface intermediates followed by hydrogenation to yield acetophenone and phenol.Keywords: biomass; density functional theory; lignin; lignin model; palladium; Pd(111); β-O-4 linkage

Transfer hydrogenation of nitroarenes with hydrazine at near-room temperature catalysed by a MoO2 catalyst

Co-reporter:Chaofeng Zhang, Jianmin Lu, Mingrun Li, Yehong Wang, Zhe Zhang, Haijun Chen and Feng Wang

Green Chemistry 2016 vol. 18(Issue 8) pp:2435-2442

Publication Date(Web):08 Dec 2015

DOI:10.1039/C5GC02460A

We present an experimental and computational study of the elementary steps of hydrazine hydrogen transfer on crystalline MoO2, and demonstrate its unique bifunctional metallic-basic properties in a catalytic hydrogenation reaction. Density functional theory (DFT) calculations suggest that the stepwise hydrogen transfer via the prior cleavage of the N–H bond rather than the N–N bond, is the key step to create the dissociated hydride and proton species on the dual Mo and O sites, marking its difference with common oxides. Crystalline MoO2 shows exceptionally high chemoselectivity toward the nitro reduction over CC, CC, and CN groups at room temperature and lower, down to 0 °C, rendering it as a promising catalytic material for hydrogenation reactions.

Oxidative coupling of anilines to azobenzenes using heterogeneous manganese oxide catalysts

Co-reporter:Min Wang, Jiping Ma, Miao Yu, Zhe Zhang and Feng Wang

Catalysis Science & Technology 2016 vol. 6(Issue 6) pp:1940-1945

Publication Date(Web):30 Oct 2015

DOI:10.1039/C5CY01015B

We herein report the transition metal oxide-catalyzed synthesis of azobenzenes through the oxidative coupling of anilines. An octahedral molecular sieve of manganese oxide, OMS-2, exhibited the best activity and selectivity. Nine examples of symmetric azobenzenes and twenty unsymmetric ones were synthesized with 62–99% conversion and 64–99% selectivity. In the aniline cross-coupling reactions, the difference of the Hammett constants of two substituted groups (Δσ) determines the selectivity to unsymmetric azobenzenes, which are the major products at Δσ < 0.32. In-depth studies reveal that the surface defect sites of the mixed-valence manganese oxide play a key role in facilitating electron transfer and activating molecular oxygen. The single-electron transfer (SET) reaction mechanism is proposed based on electron paramagnetic resonance and X-ray powder diffraction characterization.

The cascade synthesis of α,β-unsaturated ketones via oxidative C–C coupling of ketones and primary alcohols over a ceria catalyst

Co-reporter:Zhixin Zhang, Yehong Wang, Min Wang, Jianmin Lu, Chaofeng Zhang, Lihua Li, Jingyang Jiang and Feng Wang

Catalysis Science & Technology 2016 vol. 6(Issue 6) pp:1693-1700

Publication Date(Web):12 Oct 2015

DOI:10.1039/C5CY01607J

We herein report the oxidative C–C coupling of ketones and primary alcohols to produce α,β-unsaturated ketones in the absence of base additives. This cascade synthetic reaction was conducted at 150 °C in 12 h using a heterogeneous CeO2 catalyst. The conversion of acetophenone reached 74% with 89% selectivity to chalcone. A correlation between the CeO2 crystal plane and catalytic performance is established as the catalytic activities decrease in the sequence of (110) > (111) > (100). Characterization using Raman spectroscopy, CO2 temperature-programmed desorption (CO2-TPD), and in situ active site-capping tests has shown that the unusual catalysis of the CeO2 catalyst is attributed to the coexistence of basic and redox active sites. These sites synergistically catalyze the oxidation of alcohols to aldehydes and the aldol condensation to ketones. Moreover, the CeO2 catalyst can be reused several times after calcination to remove the surface-adsorbed substances.

Epoxide hydrolysis and alcoholysis reactions over crystalline Mo–V–O oxide

Co-reporter:Xiaochen Zhang, Min Wang, Chaofeng Zhang, Jianmin Lu, Yehong Wang and Feng Wang

RSC Advances 2016 vol. 6(Issue 75) pp:70842-70847

Publication Date(Web):13 Jul 2016

DOI:10.1039/C6RA10212C

Crystalline Mo–V–O oxides have been used as a catalyst for the hydrolysis and alcoholysis of propylene oxide to diols and ethers, respectively. Relationships between the active crystal facet, the acidity of Mo–V–O catalysts and the activity have been established. Our results indicate that the a–b plane is the active facet for the hydrolysis reaction.

The cascade synthesis of quinazolinones and quinazolines using an α-MnO2 catalyst and tert-butyl hydroperoxide (TBHP) as an oxidant

Co-reporter:Zhe Zhang, Min Wang, Chaofeng Zhang, Zhixin Zhang, Jianmin Lu and Feng Wang

Chemical Communications 2015 vol. 51(Issue 44) pp:9205-9207

Publication Date(Web):28 Apr 2015

DOI:10.1039/C5CC02785C

Heterogeneously catalyzed synthesis of quinazolinones or quinazolines is reported in this study. An α-MnO2 catalyst is found to be highly active and selective in the oxidative cyclization of anthranilamides or aminobenzylamines with alcohols using TBHP as an oxidant. This protocol exhibits a broad substrate scope, and is operationally simple without an additive.

Cuprous Oxide Catalyzed Oxidative CC Bond Cleavage for CN Bond Formation: Synthesis of Cyclic Imides from Ketones and Amines

Co-reporter:Dr. Min Wang;Dr. Jianmin Lu;Dr. Jiping Ma;Zhe Zhang ; Feng Wang

Angewandte Chemie 2015 Volume 127( Issue 47) pp:14267-14271

Publication Date(Web):

DOI:10.1002/ange.201508071

Abstract

Selective oxidative cleavage of a CC bond offers a straightforward method to functionalize organic skeletons. Reported herein is the oxidative CC bond cleavage of ketone for CN bond formation over a cuprous oxide catalyst with molecular oxygen as the oxidant. A wide range of ketones and amines are converted into cyclic imides with moderate to excellent yields. In-depth studies show that both α-CH and β-CH bonds adjacent to the carbonyl groups are indispensable for the CC bond cleavage. DFT calculations indicate the reaction is initiated with the oxidation of the α-CH bond. Amines lower the activation energy of the CC bond cleavage, and thus promote the reaction. New insight into the CC bond cleavage mechanism is presented.

Cuprous Oxide Catalyzed Oxidative CC Bond Cleavage for CN Bond Formation: Synthesis of Cyclic Imides from Ketones and Amines

Co-reporter:Dr. Min Wang;Dr. Jianmin Lu;Dr. Jiping Ma;Zhe Zhang ; Feng Wang

Angewandte Chemie International Edition 2015 Volume 54( Issue 47) pp:14061-14065

Publication Date(Web):

DOI:10.1002/anie.201508071

Abstract

tert-Butyl hydroperoxide (TBHP)-mediated oxidative self-coupling of amines to imines over a α-MnO2 catalyst

Co-reporter:Zhe Zhang, Feng Wang, Min Wang, Shutao Xu, Haijun Chen, Chaofeng Zhang and Jie Xu

Green Chemistry 2014 vol. 16(Issue 5) pp:2523-2527

Publication Date(Web):07 Jan 2014

DOI:10.1039/C3GC42312C

We here demonstrate a simple, efficient and eco-friendly protocol for the direct synthesis of imines from amines via a facile α-MnO2 catalyzed-procedure at rt. Up to 13 benzylic, heterocyclic, and normal aliphatic imines were synthesized with 95–99% selectivity at 82–99% conversion.

Organic linker geometry controlled synthesis of coordination polymer spheres and their thermal transformation to yolk–shell metal oxides

Co-reporter:Min Wang, Feng Wang, Jiping Ma and Jie Xu

Journal of Materials Chemistry A 2014 vol. 2(Issue 37) pp:15480-15487

Publication Date(Web):24 Jul 2014

DOI:10.1039/C4TA02535K

Precise control over size, morphology and composition of coordination polymers (CPs) is challenging but important for using these hybrid materials for many more applications. Herein, we report a protocol of preparing unitary and multinary metal–carboxylic acid coordination polymers without additives. We found that the CPs morphology was controlled by the geometric angle (∠) of carboxylic groups in the organic linkers. At the ∠120°, the mono-dispersed and uniform spherical CPs were obtained with the central distribution size ranging from nanoscale to microscale, adjusted by the precursor concentration and reaction time. We also obtained a series of spherical metal-CPs, including transition and rare earth metals (Mg, Ni, Zn, In, Y, Sm, Eu, Gd, Er, Ho, Yb and Lu) and homogeneously distributed multinary metal-CPs. Moreover, the calcination of these CPs generated unitary and multinary metal oxides with yolk–shell structure. In addition, metal-CPs contain coordinatively unsaturated metal sites, which is confirmed by probe molecule adsorption-IR spectroscopy, and could catalyze the cyanosilylation of carbonyl substrates at 25 °C. Sixteen examples were tested and produced good to excellent yields over Eu-CPs.

Investigations on the crystal plane effect of ceria on gold catalysis in the oxidative dehydrogenation of alcohols and amines in the liquid phase

Co-reporter:Min Wang, Feng Wang, Jiping Ma, Mingrun Li, Zhe Zhang, Yehong Wang, Xiaochen Zhang and Jie Xu

Chemical Communications 2014 vol. 50(Issue 3) pp:292-294

Publication Date(Web):28 Oct 2013

DOI:10.1039/C3CC46180G

Gold nanoparticles supported on ceria{110} crystal planes were more reactive than on ceria{111} and {100} in the oxidative dehydrogenation of alcohols. Kinetic analysis and a Hammett plot suggest that hydride transfer is involved, and the cationic gold is catalytically active.

Transformylating amine with DMF to formamide over CeO2 catalyst

Co-reporter:Yehong Wang, Feng Wang, Chaofeng Zhang, Jian Zhang, Mingrun Li and Jie Xu

Chemical Communications 2014 vol. 50(Issue 19) pp:2438-2441

Publication Date(Web):03 Dec 2013

DOI:10.1039/C3CC48400A

We here report a new protocol for the formylation of various amines, primary or secondary, aromatic or alkyl, cyclic or linear, mono- or di-amine, with dimethylformamide (DMF) as the formylation reagent to obtain the corresponding formamides in good to excellent yields over CeO2 catalyst. The reaction requires no homogeneous acidic or basic additives and is tolerant to water.

Lignin depolymerization (LDP) in alcohol over nickel-based catalysts via a fragmentation–hydrogenolysis process

Co-reporter:Qi Song, Feng Wang, Jiaying Cai, Yehong Wang, Junjie Zhang, Weiqiang Yu and Jie Xu

Energy & Environmental Science 2013 vol. 6(Issue 3) pp:994-1007

Publication Date(Web):03 Jan 2013

DOI:10.1039/C2EE23741E

Valorization of native birch wood lignin into monomeric phenols over nickel-based catalysts has been studied. High chemoselectivity to aromatic products was achieved by using Ni-based catalysts and common alcohols as solvents. The results show that lignin can be selectively cleaved into propylguaiacol and propylsyringol with total selectivity >90% at a lignin conversion of about 50%. Alcohols, such as methanol, ethanol and ethylene glycol, are suitable solvents for lignin conversion. Analyses with MALDI-TOF and NMR show that birch lignin is first fragmented into smaller lignin species consisting of several benzene rings with a molecular weight of m/z ca. 1100 to ca. 1600 via alcoholysis reaction. The second step involves the hydrogenolysis of the fragments into phenols. The presence of gaseous H2 has no effect on lignin conversion, indicating that alcohols provide active hydrogen species, which is further confirmed by isotopic tracing experiments. Catalysts are recycled by magnetic separation and can be reused four times without losing activity. The mechanistic insights from this work could be helpful in understanding native lignin conversion and the formation of monomeric phenolics via reductive depolymerization.

Insights into support wettability in tuning catalytic performance in the oxidation of aliphatic alcohols to acids

Co-reporter:Min Wang, Feng Wang, Jiping Ma, Chen Chen, Song Shi and Jie Xu

Chemical Communications 2013 vol. 49(Issue 59) pp:6623-6625

Publication Date(Web):04 Jun 2013

DOI:10.1039/C3CC43042A

A superhydrophobic catalyst was prepared by immobilizing Pt nanoparticles on superhydrophobic organic–inorganic hybrid silicas, which showed high activity and selectivity in the oxidation of aliphatic alcohols to carboxylic acids.

Lignosulfonate-based heterogeneous sulfonic acid catalyst for hydrolyzing glycosidic bonds of polysaccharides

Co-reporter:Xiaochen Zhang, Zhe Zhang, Feng Wang, Yehong Wang, Qi Song, Jie Xu

Journal of Molecular Catalysis A: Chemical 2013 Volume 377() pp:102-107

Publication Date(Web):October 2013

DOI:10.1016/j.molcata.2013.05.001

•Novel and reusable lignosulfonate-based heterogeneous acid catalyst was reported.•High activities in hydrolysis of polysaccharides to monosaccharides were achieved.•Better accessibility of substrate to active site accounts for superior performance.•The catalyst can be reused four times.We report a novel lignosulfonate-based heterogeneous sulfonic acid catalyst (LF) which offered high yields of monosaccharides (75–98%) in hydrolysis of polysaccharides, such as cellobiose, maltose, d-melezitose, sucrose, inulin, and starch. Specific activity in cellobiose hydrolysis was 5.6 ± 0.3 mol glucose per mol SO3H. Kinetic analysis showed that the apparent activation energy of cellobiose hydrolysis over the LF catalyst is 98.5 kJ mol−1, which was less than 110–138 kJ mol−1 for mineral acids, organic acid homogeneous catalysts or grafted sulfonic acids. The catalyst was recycled by filtration and reused four times in cellobiose hydrolysis without apparent loss of catalytic activity. NMR characterization suggests that the better accessibility of cellobiose to SO3H sites and multiple bindings of hydroxyls of cellobiose on COOH and OH sites may account for its superior performance. This is a new method of utilizing pulp industry waste as sulfonic acid precursor; otherwise sulfonation process is required for preparing heterogeneous sulfonic acid catalysts.

Heterogeneous Ceria Catalyst with Water-Tolerant Lewis Acidic Sites for One-Pot Synthesis of 1,3-Diols via Prins Condensation and Hydrolysis Reactions

Co-reporter:Yehong Wang ; Feng Wang ; Qi Song ; Qin Xin ; Shutao Xu ;Jie Xu

Journal of the American Chemical Society 2012 Volume 135(Issue 4) pp:1506-1515

Publication Date(Web):December 10, 2012

DOI:10.1021/ja310498c

The use of a heterogeneous Lewis acid catalyst, which is insoluble and easily separable during the reaction, is a promising option for hydrolysis reactions from both environmental and practical viewpoints. In this study, ceria showed excellent catalytic activity in the hydrolysis of 4-methyl-1,3-dioxane to 1,3-butanediol in 95% yield and in the one-pot synthesis of 1,3-butanediol from propylene and formaldehyde via Prins condensation and hydrolysis reactions in an overall yield of 60%. In-depth investigations revealed that ceria is a water-tolerant Lewis acid catalyst, which has seldom been reported previously. The ceria catalysts showed rather unusual high activity in hydrolysis, with a turnover number (TON) of 260, which is rather high for bulk oxide catalysts, whose TONs are usually less than 100. Our conclusion that ceria functions as a Lewis acid catalyst in hydrolysis reactions is firmly supported by thorough characterizations with IR and Raman spectroscopy, acidity measurements with IR and 31P magic-angle-spinning NMR spectroscopy, Na+/H+ exchange tests, analyses using the in situ active-site capping method, and isotope-labeling studies. A relationship between surface vacancy sites and catalytic activity has been established. CeO2(111) has been confirmed to be the catalytically active crystalline facet for hydrolysis. Water has been found to be associatively adsorbed on oxygen vacancy sites with medium strength, which does not lead to water dissociation to form stable hydroxides. This explains why the ceria catalyst is water-tolerant.

Hydrogenolysis of lignosulfonate into phenols over heterogeneous nickel catalysts

Co-reporter:Qi Song, Feng Wang and Jie Xu

Chemical Communications 2012 vol. 48(Issue 56) pp:7019-7021

Publication Date(Web):20 Apr 2012

DOI:10.1039/C2CC31414B

We report a strategy for the catalytic conversion of lignosulfonate into phenols over heterogeneous nickel catalysts. Aryl–alkyl bonds (C–O–C) and hydroxyl groups (–OH) are hydrogenated to phenols and alkanes, respectively, without disturbing the arenes. The catalyst is based on a naturally abundant element, and is recyclable and reusable.

Detection and Measurement of Surface Electron Transfer on Reduced Molybdenum Oxides (MoOx) and Catalytic Activities of Au/MoOx

Co-reporter:Dr. Feng Wang;Dr. Wataru Ueda;Dr. Jie Xu

Angewandte Chemie International Edition 2012 Volume 51( Issue 16) pp:3883-3887

Publication Date(Web):

DOI:10.1002/anie.201105922

Detection and Measurement of Surface Electron Transfer on Reduced Molybdenum Oxides (MoOx) and Catalytic Activities of Au/MoOx

Co-reporter:Dr. Feng Wang;Dr. Wataru Ueda;Dr. Jie Xu

Angewandte Chemie 2012 Volume 124( Issue 16) pp:3949-3953

Publication Date(Web):

DOI:10.1002/ange.201105922

Preparation of VO2(B) Nanoflake with Glycerol as Reductant Agent and its Catalytic Application in the Aerobic Oxidation of Benzene to Phenol

Co-reporter:Xing Chen;Jie Xu

Topics in Catalysis 2011 Volume 54( Issue 13-15) pp:

Publication Date(Web):2011 September

DOI:10.1007/s11244-011-9713-y

Nanostructured VO2(B) was prepared by employing glycerol as reductant. Key parameters of the pH value of crystallization solution and the volume ratio of glycerol to water were optimized to prepare pure phase VO2(B). The VO2(B) could catalyze the aerobic oxidation of benzene to phenol with molecular oxygen in high selectivity.

Catalytic Oxidative Dehydration of Glycerol over a Catalyst with Iron Oxide Domains Embedded in an Iron Orthovanadate Phase

Co-reporter: Feng Wang; Jie Xu;Dr. Jean-Luc Dubois; Wataru Ueda

ChemSusChem 2010 Volume 3( Issue 12) pp:1383-1389

Publication Date(Web):

DOI:10.1002/cssc.201000245

Abstract

An embedded catalyst for the oxidative dehydration of glycerol, featuring iron oxide (FeO_x) domains on the surface of an iron orthovanadate (FeVO₄) phase, is developed. Catalytic reactions are conducted in a fixed-bed reactor at 300 °C with a feed composition N₂/O₂/H₂O/glycerol=66.6:1.7:30.3:1.5. Catalytic results show that the catalyst exhibits a better performance than an FeO_x catalyst prepared by impregnation and than a mixture of FeVO₄ and Fe₂O₃. The best yield for acrylic acid was 14 %. The presence of FeO_x domains on the surface of FeVO₄ catalyzes the oxidation of acrolein to acrylic acid. The catalysts are characterized by a range of techniques. The interaction between the nanometer-sized FeO_x domains and the FeVO₄ phase is strong enough to stabilize the FeO_x and retain its high activity. The proximity of the two phases provides an environment for the dehydration of glycerol and the oxidation of acrolein to acrylic acid.

Preparation and characterization of vanadium(IV) oxide supported on SBA-15 and its catalytic performance in benzene hydroxylation to phenol using molecular oxygen

Co-reporter:Xing Chen, Wenguang Zhao, Feng Wang, Jie Xu

Journal of Natural Gas Chemistry (September 2012) Volume 21(Issue 5) pp:481-487

Publication Date(Web):1 September 2012

DOI:10.1016/S1003-9953(11)60394-0

Preparation of dispersed transition metal oxides catalyst with low oxidation state still remains a challenging task in heterogeneous catalysis. In this study, vanadium oxides supported on zeolite SBA-15 have been prepared under hydrothermal condition using V2O5 and oxalic acid as sources of vanadium and reductant, respectively. The structures of samples, especially the oxidation state of vanadium, and the surface distribution of vanadium oxide species, have been thoroughly characterized using various techniques, including N2-physisorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-visible spectra (UV-Vis) and UV-visible-near infrared spectra (UV-Vis-NIR). It is found that the majority of supported vanadium was in the form of vanadium(IV) oxide species with the low valence of vanadium. By adjusting hydrothermal treatment time, the surface distribution of vanadium(IV) oxide species can be tuned from vanadium(IV) oxide cluster to crystallites. These materials have been tested in the hydroxylation of benzene to phenol in liquid-phase with molecular oxygen in the absence of reductant. The catalyst exhibits high selectivity for phenol (61%) at benzene conversion of 4.6%, which is a relatively good result in comparison with other studies employing molecular oxygen as the oxidant.

New protocol of copper-catalyzed oxidative C(CO)C bond cleavage of aryl and aliphatic ketones to organic acids using O2 as the terminal oxidant

Co-reporter:Huifang Liu, Min Wang, Hongji Li, Nengchao Luo, Shutao Xu, Feng Wang

Journal of Catalysis (February 2017) Volume 346() pp:170-179

Publication Date(Web):1 February 2017

DOI:10.1016/j.jcat.2016.12.016

•Cu(NO3)2 could catalyze the oxidative CC cleavage of ketones to acids.•A wide range of ketones have good to excellent yields.•In situ NMR and EPR gave possible intermediates and mechanism.•Electrochemical study of copper salts in various solvents has been conducted.Catalytic oxidation of CC bond is a key technology to transform petroleum-based as well as sustainable biomass feedstock into more valuable oxygenates. We herein describe a convenient and useful oxidation strategy of converting ketones into carboxylic acids using homogeneous copper catalyst without additives and with O2 as the terminal oxidant. A wide range of aryl and aliphatic ketones as well as β–O–4 lignin models were selectively oxidized to acids via CC bond cleavage. Mechanism studies by EPR and in situ NMR elucidate the principles of Cu/O2 reactivity that involves CH bond and O2 activation via a peroxide species. This provides an important foundation for expanding the scope of useful aerobic oxidation reactions using copper catalysts.Download high-res image (59KB)Download full-size image

Oxidative C(OH)C bond cleavage of secondary alcohols to acids over a copper catalyst with molecular oxygen as the oxidant

Co-reporter:Min Wang, Jianmin Lu, Lihua Li, Hongji Li, Huifang Liu, Feng Wang

Journal of Catalysis (April 2017) Volume 348() pp:160-167

Publication Date(Web):1 April 2017

DOI:10.1016/j.jcat.2017.02.017

•Synthesis of acids via oxidative cleavage of secondary alcohols.•A wide range of secondary alcohols were oxidized to acids with up to 98% yield.•The CC bond of β-O-4 Lignin models was successfully broken up.•The CH bond is pivotal for the CC bond cleavage.Selective oxidative cleavage of CC bond is pivotal for producing functionalized molecules, useful for organic synthesis and biomass utilization. We herein report the oxidative C(OH)C bond cleavage of secondary alcohols to acids over a copper/1, 10-phenanthroline complex with molecular oxygen as the oxidant. A wide range of secondary alcohols are converted into acids with up to 98% yields. More interestingly, it is effective for breaking up lignin model systems into acids, which is rarely achieved in previous studies. Density functional theory (DFT) calculations indicate a copper-oxo-bridged oxygen dimer is the active species for the CH bond cleavage which is the rate-determining step for CC bond.Download high-res image (92KB)Download full-size image

Transfer hydrogenation of nitroarenes to arylamines catalysed by an oxygen-implanted MoS2 catalyst

Co-reporter:Chaofeng Zhang, Zhixin Zhang, Xu Wang, Mingrun Li, Jianmin Lu, Rui Si, Feng Wang

Applied Catalysis A: General (5 September 2016) Volume 525() pp:85-93

Publication Date(Web):5 September 2016

DOI:10.1016/j.apcata.2016.07.008

Organic linker geometry controlled synthesis of coordination polymer spheres and their thermal transformation to yolk–shell metal oxides

Co-reporter:Min Wang, Feng Wang, Jiping Ma and Jie Xu

Journal of Materials Chemistry A 2014 - vol. 2(Issue 37) pp:NaN15487-15487

Publication Date(Web):2014/07/24

DOI:10.1039/C4TA02535K

Hydrogenolysis of lignosulfonate into phenols over heterogeneous nickel catalysts

Co-reporter:Qi Song, Feng Wang and Jie Xu

Chemical Communications 2012 - vol. 48(Issue 56) pp:NaN7021-7021

Publication Date(Web):2012/04/20

DOI:10.1039/C2CC31414B

The cascade synthesis of quinazolinones and quinazolines using an α-MnO2 catalyst and tert-butyl hydroperoxide (TBHP) as an oxidant

Co-reporter:Zhe Zhang, Min Wang, Chaofeng Zhang, Zhixin Zhang, Jianmin Lu and Feng Wang

Chemical Communications 2015 - vol. 51(Issue 44) pp:NaN9207-9207

Publication Date(Web):2015/04/28

DOI:10.1039/C5CC02785C

Investigations on the crystal plane effect of ceria on gold catalysis in the oxidative dehydrogenation of alcohols and amines in the liquid phase

Co-reporter:Min Wang, Feng Wang, Jiping Ma, Mingrun Li, Zhe Zhang, Yehong Wang, Xiaochen Zhang and Jie Xu

Chemical Communications 2014 - vol. 50(Issue 3) pp:NaN294-294

Publication Date(Web):2013/10/28

DOI:10.1039/C3CC46180G

Transformylating amine with DMF to formamide over CeO2 catalyst

Co-reporter:Yehong Wang, Feng Wang, Chaofeng Zhang, Jian Zhang, Mingrun Li and Jie Xu

Chemical Communications 2014 - vol. 50(Issue 19) pp:NaN2441-2441

Publication Date(Web):2013/12/03

DOI:10.1039/C3CC48400A

Insights into support wettability in tuning catalytic performance in the oxidation of aliphatic alcohols to acids

Co-reporter:Min Wang, Feng Wang, Jiping Ma, Chen Chen, Song Shi and Jie Xu

Chemical Communications 2013 - vol. 49(Issue 59) pp:NaN6625-6625

Publication Date(Web):2013/06/04

DOI:10.1039/C3CC43042A

Oxidative coupling of anilines to azobenzenes using heterogeneous manganese oxide catalysts

Co-reporter:Min Wang, Jiping Ma, Miao Yu, Zhe Zhang and Feng Wang

Catalysis Science & Technology (2011-Present) 2016 - vol. 6(Issue 6) pp:NaN1945-1945

Publication Date(Web):2015/10/30

DOI:10.1039/C5CY01015B

The cascade synthesis of α,β-unsaturated ketones via oxidative C–C coupling of ketones and primary alcohols over a ceria catalyst

Co-reporter:Zhixin Zhang, Yehong Wang, Min Wang, Jianmin Lu, Chaofeng Zhang, Lihua Li, Jingyang Jiang and Feng Wang

Catalysis Science & Technology (2011-Present) 2016 - vol. 6(Issue 6) pp:NaN1700-1700

Publication Date(Web):2015/10/12

DOI:10.1039/C5CY01607J

CAS:1403336-96-8

CAS:917224-71-6

1H-1,4-Diazepine-1,4(5H)-dicarboxaldehyde, tetrahydro- (9CI)

CAS:321898-61-7

1H-1,4-Diazepine-1,4(5H)-dicarboxaldehyde, tetrahydro- (9CI)

CAS:215667-40-6

N-[[4-(TRIFLUOROMETHYL)PHENYL]METHYL]-FORMAMIDE

CAS:180207-85-6

N-[[4-(TRIFLUOROMETHYL)PHENYL]METHYL]-FORMAMIDE

CAS:176978-26-0

CAS:138867-16-0

2-(2-FLUOROPHENYL)-1H-QUINAZOLIN-4-ONE

1H-Isoindole-1,3(2H)-dione, 2-[(4-chlorophenyl)methyl]-

CAS:131523-32-5

1H-Isoindole-1,3(2H)-dione, 2-[(4-chlorophenyl)methyl]-

CAS:108478-16-6

1-Propanone, 3-hydroxy-1,2-diphenyl-

CAS:100010-99-9

2-octoxypropan-1-ol