AICHE JOURNAL
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2024
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IF 3.5
Yang Zhao,Qian Wang,Huifang Wu,Lirong Zheng,Zhexi Gao,Xuanlin Guo,Xingzhong Cao,Dianqing Li,Junting Feng
Reductive amination of biomass aldehydes is a vital process to synthesize chemical intermediates primary amine, but the selectivity is severely compromised by the self-condensation of highly reactive imine intermediates. Herein, we proposed a solution by manipulating the adsorption configuration of secondary imine via defect engineering. Specifically, a gradient reduction strategy was used to adjust the driving force of NiCo alloy crystallization, thus motivating the formation of metal vacancy clusters. The primary amine selectivity was raised from 70.9% to 95.1% with defect concentration increased from 36.1% to 42.5% on catalysts. In situ fourier transform infrared spectroscopy (FTIR) and density functional theory demonstrated metal vacancy clusters induced remarkable Ni Co electron transfer, which strengthened electronic coupling between secondary imine with catalyst, resulting in a flat configuration that was conducive to CN bond breakage to guarantee smooth conversion into primary amines. This catalyst exhibited potential real-life application prospects for its low cost, universality in reductive amination of various aldehydes, and long-life reusability.
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APPLIED SURFACE SCIENCE
·
2024
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IF 6.3
Jingyi Yang,Yongzhen Gao,Jie Fan,Jieqiong Wang,Tao Yang,Zezheng Bing,Meng Zhang,Zhongyi Liu
Tuning the metal-support interaction (MSI) between highly dispersed nanosized metal particles and the support plays a pivotal role in the activity and selectivity of polyaromatics selective hydrogenation. In this work, the supported bimetallic Ni-Ru/SiO 2 -SEA catalyst was prepared by a strong electrostatic adsorption (SEA) strategy, and applied for the selective hydrogenation of biphenyl (BP) to cyclohexylbenzene (CHB). Compared to the catalysts prepared by the conventional incipient wetness impregnation method and Ni/SiO 2 -SEA, the significant effects of MSI and hydrogen spillover on Ni-Ru/SiO 2 -SEA facilitated the highly exposed and uniformly dispersed electron-deficient Ni δ+ (0 < δ < 2) species, which could enhance adsorption and activation of the electron-withdrawing phenyl group and H 2 , thereby promoting the efficient and selective conversion of BP to CHB. At the conditions of 160 ℃ and 2 MPa H 2 pressure, BP conversion over Ni-Ru/SiO 2 -SEA reached nearly 100 % within 3 h, achieving a remarkable selectivity of 97.9 % towards CHB, along with a high turnover frequency of 2756.9 h −1 for the active metallic Ni sites. Importantly, according to the kinetic simulations, the hydrogenation rate constant of Ni-Ru/SiO 2 -SEA was the highest (2.76 × 10 -2 mol·g −1 ·h −1 ) among the employed catalysts. Moreover, after six consecutive cycles, no obvious decline in hydrogenation efficiency was observed, confirming the remarkable activity and stability of Ni-Ru/SiO 2 -SEA. Furthermore, the activation of BP and desorption of CHB pathway on the Ni δ+ species were elaborated through temperature-programmed desorption characterization, highlighting the prominent contribution of MSI in enhancing the selective hydrogenation of polyaromatics.
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DALTON TRANSACTIONS
·
2024
·Vol. 53
·期 5
·1989-1998
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IF 3.5
Yanshu Liu,Guanyun Zhang,Dexin Wang,Guanjie Chen,Fangfang Gao,Chen-Ho Tung,Yifeng Wang
A cryptand-like Ti-coordination compound, namely Ti12Cs, comprising two Ti6-salicylate cages and hosting two Cs+ ions, was synthesized by the solvothermal method. It exhibits strong visible-light absorption with an absorption band edge of 652 nm, attributed to the electron transition from salicylate ligands to Ti ions. Electrochemical impedance, visible-light transient photocurrent response, and photoluminescence spectra confirm that Ti12Cs has excellent visible-light response and charge-separation properties. Ti12Cs can be used as a heterogeneous and recyclable photocatalyst for CO2/epoxide cycloaddition, with high utilization efficiency of visible-light under mild conditions. The mechanism investigation points to a synergistic effect of photocatalysis and Lewis acid catalysis.
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CHEMISTRY-A EUROPEAN JOURNAL
·
2016
·Vol. 22
·期 24
·8368-8375
·
IF 5.771
Yan Leng,Dan Lu,Chenjun Zhang,Pingping Jiang,Weijie Zhang,Jun Wang
Graphical This cat has five lives : Novel ionic polymer microspheres bearing a Co III –salen moiety were demonstrated to be highly efficient catalysts (high activity, easy recovery, and reusable) for the cycloaddition reaction of CO 2 and epoxides (see figure). We report a unique strategy to obtain the bifunctional heterogeneous catalyst TBB-Bpy@Salen-Co (TBB=1,2,4,5-tetrakis(bromomethyl)benzene, Bpy=4,4’-bipyridine, Salen-Co= N , N ’-bis({4-dimethylamino}salicylidene)ethylenediamino cobalt(III) acetate) by combining a cross-linked ionic polymer with a Co III –salen Schiff base. The catalyst showed extra high activity for CO 2 fixation under mild, solvent-free reaction conditions with no requirement for a co-catalyst. The synthesized catalyst possessed distinctive spherical structural features, abundant halogen Br − anions with good leaving group ability, and accessible Lewis acidic Co metal centers. These unique features, together with the synergistic role of the Co and Br − functional sites, allowed TBB-Bpy@Salen-Co to exhibit enhanced catalytic conversion of CO 2 into cyclic carbonates relative to the corresponding monofunctional analogues. This catalyst can be easily recovered and recycled five times without significant leaching of Co or loss of activity. Moreover, based on our experimental results and previous work, a synergistic cycloaddition reaction mechanism was proposed.
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ACS Applied Materials & Interfaces
·
2017
·
IF 7.504
Qinrui Fu,Yuan Meng,Zilin Fang,Quanqin Hu,Liang Xu,Wenhua Gao,Xiaochun Huang,Qiao Xue,Ya-Ping Sun,Fushen Lu
Boron nitride nanosheets (BNNS) were used to anchor bimetallic Pd–Fe nanoparticles for Suzuki–Miyaura coupling catalysts. The bimetallic nanoparticles were found to be core–shell in structure, and their formation was likely facilitated by their interactions with the BNNS. The Pd–Fe/BNNS catalysts were highly effective in representative Suzuki–Miyaura reactions, with performances matching or exceeding those of the state-of-the-art methods. Specifically, the superior catalytic activities were characterized by generally shortened reaction times, minimal Pd usage, excellent reusability of the catalysts and high or nearly quantitative conversion yields in a benign solvent system without the need for any special conditions, such as ligands and surfactants or inert gas protection. The obvious advantages of the Pd–Fe/BNNS over similar catalysts based on other supports, such as reduced graphene oxide (rGO), suggest that BNNS may be developed into a versatile platform for many other important catalytic reactions.
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JOURNAL OF CHROMATOGRAPHY A
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2016
·
IF 3.926
Yunzhong Zheng,Meiling Qi,Ruonong Fu
This work presents the first example of utilization of graphitic carbon nitride (g-C 3 N 4 ) as stationary phase for capillary gas chromatographic (GC) separations. The statically coated g-C 3 N 4 column showed the column efficiencies of 3760 plates/m and weak polarity. Its resolving capability and retention behaviours were investigated by using the Grob test mixture, and mixtures of diverse types of analytes, and structural and positional isomers. The results showed superior separation performance of the g-C 3 N 4 stationary phase for some critical analytes and preferential retention for aromatic analytes. Specifically, it exhibited high-resolution capability for aromatic and aliphatic isomers such as methylnaphthalenes and dimethylnaphthalenes , phenanthrene and anthracene and alkane isomers. In addition, g-C 3 N 4 column showed excellent thermal stability up to 280 °C and good repeatability with relative standard deviation (RSD) values less than 0.09% for intra-day, below 0.23% for inter-day and in the range of 1.9–8.4% for between-column, respectively. The advantageous separation performance shows the potential of g-C 3 N 4 and related materials as stationary phase in GC and other separation technologies.
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Scientific Reports
·
2016
·Vol. 6
·期 1
·1-9
·
IF 5.228
Luo Qin,Zhao Changwei,Liu Guixia,Ren Hao
A low-cost and easily constructed porous aromatic framework (PAF-45) was successfully prepared using the Scholl reaction. PAF-45 was, for the first time, used to remove perfluorooctane sulfonate (PFOS) from aqueous solution. Systematic experiments were performed to determine the adsorption capacity of PAF-45 for PFOS and to characterize the kinetics of the adsorption process. The adsorption of PFOS onto PAF-45 reached equilibrium in 30 min and the adsorption capacity of PAF-45 for PFOS was excellent (5847 mg g −1 at pH 3). The amount of PFOS adsorbed by PAF-45 increased significantly as the cation (Na + , Mg 2+ , or Fe 3+ ) concentration increased, which probably occurred because the cations enhanced the interactions between the negatively charged PFOS molecules and the positively charged PAF-45 surface. The cations Na + , Mg 2+ and Fe 3+ were found to form complexes with PFOS anions in solution. Density functional theory was used to identify the interactions between PFOS and Na + , Mg 2+ and Fe 3+ . We expect that materials of the same type as PAF-45 could be useful adsorbents for removing organic pollutants from industrial wastewater and contaminated surface water.
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INTERNATIONAL BIODETERIORATION & BIODEGRADATION
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2015
·
IF 2.131
Yuancai Lv,Lianghao Li,Yuancai Chen,Zhenghua Tang,Yongyou Hu
Polybrominated diphenyl ethers (PBDEs) are emerging persistent organic pollutants and the degradation of PBDEs is still a tremendous challenge owing to their extreme persistence and recalcitrance. In this study, Pseudomonas putida was employed for bioremediation of four PBDE congeners (BDE47, 15, 3 and diphenyl ether (DE)) with an initial concentration of 2 mg/L and the cometabolism of PBDEs was illustrated via kinetics analysis and metabolic mechanism. The biodegradation kinetics analysis suggested that PBDEs was inversely proportional to the number of bromine substituted on diphenyl ether. Both glucose (24 mg/L) and biphenyl (10 mg/L) played a positive role in promoting the biodegradation of PBDEs. The growth kinetics analysis indicated that glucose had uncompetitive inhibition on PBDEs consumption while both competitive and uncompetitive inhibition existed in biphenyl-PBDEs binary substrate system. Furthermore, the intermediates were identified by GC–MS and the main tentative degradation pathways were proposed. The angular dioxygenation was the main pathway for PBDEs degradation, while lateral dioxygenation could be induced when biphenyl was added.
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TALANTA
·
2014
·
IF 3.511
Guijiang Zhang,Xiaohuan Zang,Zhi Li,Chun Wang,Zhi Wang
In this study, polydimethylsiloxane/metal-organic frameworks (PDMS/MOFs), including PDMS/MIL-101 and PDMS/MOF-199, were immobilized onto a stainless steel wire through sol–gel technique as solid-phase microextraction (SPME) fiber coating. The prepared fibers were used for the extraction of some polycyclic aromatic hydrocarbons (PAHs) from water samples prior to gas chromatography–mass spectrometry (GC–MS) analysis. Under the optimized experiment conditions, the PDMS/MIL-101 coated fiber exhibited higher extraction efficiency towards PAHs than that of PDMS/MOF-199. Several parameters affecting the extraction of PAHs by SPME with PDMS/MIL-101 fiber, including the extraction temperature, extraction time, sample volume, salt addition and desorption conditions, were investigated. The limits of detection (LODs) were less than 4.0 ng L −1 and the linearity was observed in the range from 0.01 to 2.0 µg L −1 with the correlation coefficients ( r ) ranging from 0.9940 to 0.9986. The recoveries of the method for the PAHs from water samples at spiking levels of 0.05 and 0.2 µg L −1 ranged from 78.2% to 110.3%. Single fiber repeatability and fiber-to-fiber reproducibility were less than 9.3% and 13.8%, respectively.
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ACS Applied Materials & Interfaces
·
2014
·
IF 5.9
Lina Li,Kun Cai,Pengyuan Wang,Hao Ren,Guangshan Zhu
Porous organic frameworks (POFs), with their excellent performance in catalysis, electricity, sensor, gas storage, and separation, have attracted a great deal of attention from researchers all over the world. Generally, the monomers of POF materials require a rigid three-dimensional molecule configuration together with special functional groups, as well as being triggered by noble metal catalysts. Here we report a low-cost and easy-construction strategy for synthesizing PAF materials. A series of flat multi-benzene compounds are selected as building units, and those phenyl rings could couple together to form polymeric skeletons. The BET surface areas of resulting PAFs are moderate, ranging from 777 to 972 m2 g–1. However, they unexpectedly exhibit superior gas sorption capacities. At 1.0 bar and 77 K, the H2 uptake of PAF-48 reaches 215 cm3 g–1. In addition, PAF-49 shows excellent performance in carbon dioxide and methane sorption, with values of 104 and 35 cm3 g–1, respectively. With those adsorption properties, these PAF materials could be considered as potential candidates for energetic gas adsorbents.
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ELECTROCHIMICA ACTA
·
2013
·
IF 3.777
Zhiqiao He,Keji Lin,Junjun Sun,Lina Wen,Chao Gao,Jianmeng Chen,Shuang Song,Yanyun Qian,Weiping Liu
A kinetic model for the electrochemical dechlorination of polychlorinated biphenyls (PCBs) will be an important contribution to the design and optimization of a continuous reactor. Initially, the electrocatalytic hydrodechlorination of 2-chlorobiphenyl (2-ClBP) to biphenyl at a palladium-modified nickel foam (Pd/Ni) cathode in a batch reactor was used as a model reaction for a quantitative study of the influences of the operating parameters, including temperature, the initial concentrations of PCBs, current density and the amount of Pd loading, on the apparent reaction rate. The dechlorination was found to follow pseudo first-order kinetics with respect to the 2-ClBP concentration. It was also found that a simple global power law rate equation , with Arrhenius dependency, can be used to describe the correlation between the pseudo first-order reaction rate constants and the reaction conditions. Subsequently, a mathematical model for predicting the performance of reductive dechlorination of 2-ClBP on Pd/Ni electrodes in a continuous stirred tank reactor was constructed, based on the batch-reaction kinetics. The suitability of the model was validated by performing experiments in and out of the range of reaction conditions applied in the batch reactor. The results show that the calculated values are a good fit to the experimental data.
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JOURNAL OF CHROMATOGRAPHY A
·
2017
·
IF 3.981
Yunzhong Zheng,Qing Han,Meiling Qi,Liangti Qu
Seaweed-like graphitic carbon nitride (g-C 3 N 4 ) has a unique porous architecture composed of interlocking g-C 3 N 4 nanofibers (NF-C 3 N 4 ) with much higher surface area than bulk g-C 3 N 4 and shows good potential in separation science. This work investigated the separation performance of NF-C 3 N 4 as stationary phase for capillary gas chromatographic (GC) separations. The NF-C 3 N 4 column exhibits weak polarity and high column efficiency of 4728 plates/m for n -dodecane. Importantly, it displays good separation performance for a wide range of analytes and shows different retention behaviors from the bulk g-C 3 N 4 column and commercial HP-5MS column with 5% phenylpolysiloxane. Particularly, it shows high resolving capability for both aliphatic and aromatic isomers. In addition, NF-C 3 N 4 column has high thermal stability up to 280 °C and good separation repeatability with relative standard deviation (RSD) values in the range of 0.29–0.61% for intra-day, 0.56–1.1% for inter-day and 2.0–4.9% for between-column, respectively. Moreover, it was applied for the determination of isomer impurities in real samples, showing good potential in GC applications.
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