ANALYTICA CHIMICA ACTA
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2020
·
IF 5.977
Kang Luo,Haicheng Chen,Qing Zhou,Zhihong Yan,Zhengquan Su,Kang Li
Calcium fluoride (CaF 2 ) quantum dots have many applications in various fields. But there is no report on fluorescent characteristics of CaF 2 quantum dots (CaF 2 QDs). Here, a synthesis of multiple-color emission CaF 2 QDs by changing the temperature, time and raw ratio is reported, by which the CaF 2 QDs with purple, blue, green, and yellow emission can be obtained, respectively. They were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM). On this basis, a novel molecular imprinting ratiometric fluorescence sensor (MIR sensor) had been constructed based on the prepared CaF 2 QDs and CdTe QDs, in which the yellow emission CaF 2 QDs was used as a responsive signal material and the red emission CdTe QDs was served as a reference signal material. And the β-CD and methylacrylic acid (MAA) as bifunctional monomers were used for constructing the specific molecularly imprinted polymers (MIPs) in MIR sensor. This MIR sensor was applied for highly selective and excellent sensitive detection of 5-hydroxymethylfurfural (HMF). Under optimum conditions, it exhibited an excellent linear relationship between the fluorescence intensity ratio (I 599 /I 625 ) and the concentration of HMF in the range of 0.1–6.0 μg/mL with a detection limit of 0.043 μg/mL. Finally, the established HMF-MIR sensor was successfully utilized to detect HMF in honey with satisfactory results. This work provided a reference for the application of the CaF 2 QDs and the detection of the furfural substances.
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ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Tao Gan,Yifei Liu,Qian He,Hao Zhang,Xiaohui He,Hongbing Ji
Catalytic conversion of biomass-derived 5-hydroxymethylfurfural (HMF) into high-quality biofuel 2,5-dimethylfuran (DMF) is significant for the utilization of biomass but remains a substantial challenge. Herein, we report a straightforward, eco-friendly, and scalable ball milling method for the synthesis of Co-alloyed Pt (Pt1/Co) single-atom alloy (SAA) catalysts at kilogram levels. The catalysts exhibit superior catalytic performance for the hydrodeoxygenation of HMF to DMF, obtaining 100% HMF conversion and 92.9% selectivity to DMF under 1.0 MPa H2 at 180 °C for 2 h. The reaction pathway is also investigated, which shows that the hydrogenolysis of the C═O bond in HMF to form 2,5-dihydroxymethylfuran is the main route during the hydrodeoxygenation and promoted by the synergistic effect of Pt and Co. Pt1/Co SAA catalysts display excellent stability without aggregation after five successive runs. More inspiringly, our method achieves the mass production of Pt1/Co at the kilogram scale, rendering its potential for practical applications. Moreover, by varying acetylacetonate precursors, we show the general synthesis of different Co-supported noble metal SAA catalysts (M1/Co, M = Pd, Ru, Ir, and Rh). Our findings not only offer a facile and readily scalable synthetic approach of SAA catalysts but also open new avenue to the exploitation of biomass.
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CHINESE JOURNAL OF CATALYSIS
·
2020
·
IF 6.146
Xuemei Li,Junying Tian,Hailong Liu,Congkui Tang,Chungu Xia,Jing Chen,Zhiwei Huang
A highly efficient and green process was developed for the synthesis of useful 5-amino-1-pentanol (5-AP) from biomass-derived dihydropyran by coupling the in situ generation of 5-hydroxypentanal (5-HP, via the ring-opening tautomerization of 2-hydroxytetrahydropyran (2-HTHP)) and its reductive amination over supported Ni catalysts. The catalytic performances of the supported Ni catalysts on different oxides including SiO 2 , TiO 2 , ZrO 2 , γ-Al 2 O 3 , and MgO as well as several commercial hydrogenation catalysts were investigated. The Ni/ZrO 2 catalyst presented the highest 5-AP yield. The characterization results of the oxide-supported Ni catalysts showed that the Ni/ZrO 2 catalyst possessed high reducibility and a high surface acid density, which lead to the enhanced activity and selectivity of the catalyst. The effect of reaction parameters on the catalytic performance of the Ni/ZrO 2 catalyst was studied, and a high 5-AP yield of 90.8% was achieved in the reductive amination of 2-HTHP aqueous solution under mild conditions of 80 °C and 2 MPa H 2 . The stability of the Ni/ZrO 2 catalyst was studied using a continuous flow reactor, and only a slight decrease in the 5-AP yield was observed after a 90-h time-on-stream. Additionally, the reaction pathways for the reductive amination of 2-HTHP to synthesize 5-AP were proposed.
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CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2020
·
IF 2.627
Xianfeng Liu,Fu Yang,Shuying Gao,Bo Shao,Shijian Zhou,Yan Kong
Design and synthesis of low cost and efficacious industrial catalyst for the oxidation of styrene has been an important research project. Herein, ZSM-5 zeolite containing tetrahedral vanadium (V) and Brønsted acid sites (V-H-ZSM-5) was prepared, and identified by characterizations such as XRD, SEM, UV–vis, NH 3 -TPD, H 2 -TPR N 2 -adsorption/desorption and FTIR. V-H-ZSM-5 performed extremely enhanced catalytic activity for the oxidation of styrene with 30% H 2 O 2 at 40 °C. Moreover, in-situ FTIR spectrum was used to investigate the catalytic mechanism. The results demonstrate that Brønsted acid site could not only increase the adsorption concentration of styrene in the micropores of V-H-ZSM-5 via the π complex interaction between double bond of styrene and Brønsted acid sites, but also increase the oxidation potential of H 2 O 2 . The synergetic action of tetrahedral vanadium (V) and Brønsted acid enhanced the catalytic activity for the oxidation of styrene with 30% H 2 O 2 . Impressively, V-H-ZSM-5 performed high reusability within five runs at a low reaction temperature (40 °C) for the first time.
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Reaction Chemistry & Engineering
·
2020
·Vol. 5
·期 3
·539-546
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IF 3.441
Guangcai Zhang,Lu Zhang,Xuesong Wang,Aicheng Chen,Qinhui Zhang
This work presented microfluidic processing of zeolite films in a capillary microreactor and its potential application for biomass conversion. Uniform and continuous HZSM-5 zeolite films were fabricated under a continuous flow hydrothermal system in which the film thickness could be precisely tuned by flow rate and synthesis time. The catalytic performance of this acidic HZSM-5 film capillary microreactor was evaluated by the continuous flow acetalisation reaction of glycerol with acetone, affording ∼62.61% solketal yield under mild and solvent free conditions. No deactivation was observed even after 100 h, indicating the excellent stability of this HZSM-5 film capillary microreactor. This microfluidic processing strategy provided an extended applicability in the fabrication of zeolite film-based capillary microchannels with a high length-to-diameter ratio or other chip-based microchannel devices.
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ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Heng Ban,Youdi Zhang,Shuaibo Chen,Youwei Cheng,Teng Pan,Lijun Wang,Xi Li
In this contribution, readily available 5-methyl furfural (MF) derived from biomass was used as an excellent substitute of the chemically unstable 5-hydroxymethylfurfural (HMF) for preparing the commercial precursor 2,5-furandicarboxylic acid (FDCA). MF was catalytically oxidized by air into FDCA in acetic acid over homogeneous Co/Mn/Br catalysts at 130–170 °C. It was found that both the substitute reactivity and the ring chemical stability have a remarkable impact on the yield of aromatic dicarboxylic acids. The effects of reaction temperature, pressure, catalyst composition and concentration, water concentration in the solvent, and substrate/solvent mass ratio on both the main reaction and the side reaction were investigated systematically and thoroughly using HPLC and an online tail gas monitoring system. Under optimized conditions, the oxidation of MF gave 100% conversion of MF and 75.8% yield of FDCA with 99.6% purity. It was also proven that the addition of 200 ppm cerium could work well at low temperatures (130–140 °C) for enhancing FDCA selectivity via suppressing the side reactions.
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RSC Advances
·
2020
·Vol. 10
·期 37
·22126-22136
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IF 3.119
Hongchang Yu,Fuwei Li,Wen He,Caifeng Song,Yansong Zhang,Zhixia Li,Hongfei Lin
Micro–mesoporous ZSM-5 with different Si/Al ratios (MZ-X, X = 27, 80, 150) were synthesized by adding microcrystalline cellulose (MCC) as co-template into the hydrothermal synthesis process of zeolites. The resultant ZSM-5 were used for catalytic cracking of high density polyethylene (HPDE) and polypropylene. It was found that introduction of MCC significantly enhanced the formation of mesopores and strong acid sites. MZ-27 achieved the highest oil yield: 21.5% for HPDE and 32.1% for polypropylene, and the light aromatics (BTEX) selectivity therein were 87.6% and 79.7%, respectively. HZ-150 (MCC-free ZSM-5, Si/Al = 150) achieved the highest gas yield: 85.4% for HDPE and 76.7% for polypropylene, and the light olefins (C2–4) selectivity therein were 44% and 48.3%, respectively. The dense acidic sites and mesoporous structure of MZ-27 were responsible for its better activity for producing aromatic products. The moderate acidity and microporous structure of HZ-150 were helpful for producing light olefins from catalytic cracking of polyolefin plastics.
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Arabian Journal of Chemistry
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2020
·
IF 4.762
Muhammad Sajid,Yuchen Bai,Dehua Liu,Xuebing Zhao
Fructose was converted to 5-hydroxymethylfurfural (HMF), an important biomass-derived platform chemical, under mild conditions (100–130 °C) with several organic acids including p -toluene sulfonic ( p TSA), oxalic, maleic, malonic and succinic acids as the catalysts. The process kinetics was compared considering fructose dehydration to HMF as the objective reaction and condensation of fructose and HMF to humin and rehydration of HMF as the main side reactions. DMSO was found to be the most effective solvent reaction medium to obtain high fructose conversion and HMF yield. Observed kinetic modeling illustrated that the rehydration and condensation of HMF in DMSO actually could be neglected, especially for the oxalic acid catalyzed system. The determined observed activation energy for fructose conversion to HMF and humin in DMSO medium was 33.75 and 24.94 kJ/mol for p TSA catalyzed system, and 96.51 and 78.39 kJ/mol for oxalic acid-catalyzed system, respectively. HMF yields of 90.2% and 84.1% were obtained for p TSA and oxalic acid catalyzed systems, respectively.
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ENERGY
·
2020
·
IF 6.082
Yuchen Ya,Xiaokang Nie,Weiwei Han,Longkai Xiang,Mingyan Gu,Huaqiang Chu
The effects of 2, 5-dimethylfuran (DMF)/ethanol addition on the atomized combustion soot formation characteristics of n-heptane/iso-octane coflow diffusion flames are systemically studied. The changes of soot particles and deposition morphology at different heights in the flame of reference fuel with 15% ethanol (E15) and 15% DMF (DMF15) are analyzed. Results show that the addition of oxygenated fuels can increase the flame heights and decrease the brightness. With the addition of 15% ethanol and DMF, the flame heights are increased by 11.29% and 19.35% respectively, and the brightness of the edge region of the middle section of DMF15 flame is enhanced. At the nozzle, the average temperature of E15 flame increases by 80 K. The high temperature region of E15 flame enlarged and the average temperature difference of different heights is higher than 50 K. As for DMF15, the high temperature region of flame is constant, and the average temperature difference between various heights is smaller than 35 K. For three fuels, the size of the sediment particles formed at the low height above burner (HAB = 20 mm) is large, and the obvious pore structure can be seen at HAB = 60 mm. The addition of oxygenated fuels makes the pore structure distribution regular and the porosity decreases, and DMF15 (porosity = 0.2670) has larger pore structure than E15 (porosity = 0.1557). The oxygenated fuel can inhibit the formation of soot precursors and the agglomeration of soot particles, but the increase of particle size in the middle region of flame is promoted because of the increase of flame height and residence time of soot particles. As a result, the soot particle size of oxygenated fuel is decreased greatly in the oxidation stage, and the soot particle size of DMF15 (40.4%) is decreased more than that of E15 (37.1%). The effect of ethanol and DMF addition on the activation energy of low position soot is not obvious, which is about 130 kJ/mol. In the middle position of the flame, the activation energy of E15 is the highest (159.32 kJ/mol), and the activation energy of DMF15 is the smallest (148 kJ/mol). At the high position, E15 (212.07 kJ/mol) and DMF15 (226.73 kJ/mol) are less than that of DE0 (235.03 kJ/mol) respectively, indicating that the activation energy of the mature soot reduces, which is beneficial to the oxidative removal. Ethanol can dilute the fuel and increase the oxygen concentration in the mixture, while DMF can delay the ignition and prolong the residence time of soot and increase the content of disordered carbon in mature soot particles.
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BIORESOURCE TECHNOLOGY
·
2020
·
IF 7.539
Kai Li,Guan Zhang,Ze-xiang Wang,Bin Hu,Qiang Lu
An efficient process was developed to selectively produce monocyclic aromatic hydrocarbons (MAHs) from ex-situ catalytic fast pyrolysis (CFP) of pine assisted with calcium formate (CF) over bimetal-modified HZSM-5. Mo and another metal (Mg, Ga or Zn) were used to modify the HZSM-5, and the as-synthesized bimetal-modified HZSM-5 catalysts were utilized for both pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and lab-scale CFP tests with CF as a hydrogen donor to selectively obtain MAHs. The results revealed that the presence of CF and Mg-Mo modified HZSM-5 (0.5Mg1Mo/HZ) exhibited excellent capability for MAHs production with tiny generation of polycyclic aromatic hydrocarbons (PAHs). The maximum MAHs yield attained 12.79 wt% at 650 °C from Py-GC/MS with the CF-to-pine (CF-to-PN) ratio of 3 and catalyst-to-pine (CA-to-PN) ratio of 11, and became 9.67 wt% from lab-scale device with CF-to-PN and CA-to-PN ratios of 0.5 and 4, respectively. In addition, compared with HZSM-5, 0.5Mg1Mo/HZ possessed better anti-deactivation ability.
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Catalysis Science & Technology
·
2019
·Vol. 9
·期 24
·7034-7044
·
IF 5.726
Liwei Zhang,Huaike Zhang,Zhiqiang Chen,Qiang Ning,Suyao Liu,Jie Ren,Xiaodong Wen,Yong-Wang Li
To correlate the relationship between the Al distribution and the catalytic performance of long-chain olefin aromatization, several ZSM-5 zeolites with different Al locations and proximities were prepared via adjusting the hydrothermal synthesis conditions. Characterization by XRD, SEM and N2-adsorption indicated that all the as-prepared ZSM-5 zeolites exhibited high crystallinities, uniform morphologies and open channels. However, a great difference in the framework Al (AlF) positions was observed by 27Al MAS NMR and UV-vis-DRS of Co(II) ions, thus leading to the distinct acidity of various zeolites as determined by NH3-TPD and Py-IR. In 1-octene aromatization reaction, ZSM-5 catalysts exhibited significantly different catalytic performances and reaction pathways, which were closely related to the types and locations of the AlF atoms. The ZSM-5 zeolite catalyst with the most abundant single Al sites exhibited the lowest aromatics selectivity, while Al pairs in the framework were more favorable to the formation of aromatics. Moreover, the product distribution revealed that the Al pairs in the channel intersections of the ZSM-5 zeolite were responsible for the improved selectivity to heavy aromatics due to the fewer space restrictions; however, the Al pairs in the sinusoidal and straight channels with severe size restrictions suppressed the generation of bigger aromatics on the Al sites. This result provided a new potential method for precisely tailoring the catalytic selectivity in olefin conversion and upgrading the Fischer–Tropsch oil.
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Journal of Central South University
·
2020
·Vol. 26
·期 11
·2974-2986
·
IF 1.249
Xu Si-quan,Pan Dong-hui,Xiao Guo-min
With the aim of achieving a high 5-hydroxymethylfurfural (HMF) yield from glucose with H-ZSM-5 catalyst at low cost, three inexpensive biphasic reaction systems, H 2 O—tetrahydrofuran (THF), H 2 O—2-methyltetrahydrofuran (MeTHF) and H 2 O’2-butanol, were discovered and proved to be particularly effective in promoting the formation of HMF from glucose over H-ZSM-5 zeolite. In order to determine the optimal process conditions, the effects of various experimental variables, such as reaction temperature, reaction time, catalyst dosage, volume of organic solvent, as well as inorganic salt type on glucose conversion to HMF in three systems were investigated in detail. It was found that under optimal reaction conditions, H 2 O—THF, H 2 O—2-butanol and H 2 O—MeTHF allowed the glucose dehydration process to achieve HMF yields of up to 61%, 59%, and 50%, respectively. Moreover, in the three biphasic systems, the H-ZSM-5 catalyst was also demonstrated to maintain excellent stability. Thus, the catalytic approach proposed in this paper can be believed to have potential prospects for industrially efficient and low-cost production of HMF.
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