CATALYSIS LETTERS
·
2022
·Vol. 153
·期 10
·3074-3091
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IF 2.936
Faizan Muhammad,Saeed Aamir,Song Piao,Zhang Ruirui,Liu Ruixia,Chang Zhi,Wu Liuzhu,Zhang Manyuan
Vanadium phosphorous oxide (VPO) catalysts have been recognized as heterogeneous catalyst for selective oxidation of low-carbon alkanes i.e., n -butane toward maleic anhydride. This process has widely gained attention globally due to its highly selective and cost-effective process. Herein, we employed Cd 0 . 2 Zn 0 . 8 S as a support for the VPO catalyst and evaluated its n -butane catalytic performance. Compared to the unpromoted catalyst (Blank-VPO), a higher n -butane conversion and MA yield were successfully obtained from the promoted catalyst (Cd 0 . 2 Zn 0 . 8 S@VPO). Interestingly, it reduces the byproducts, i.e., CO 2 and CO emission. Characterization methods such as TGA, XRD, EDS, SEM, FTIR, NH 3 -TPD, XPS, TEM, and Raman spectroscopy were used to characterize the Cd 0 . 2 Zn 0 . 8 S, VPO precursor and catalyst. Graphical Abstract
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2022
·
IF 7.139
Xiaoming Liu,Yinchu Zhang,Hongwei Wang,Jiajun Yan,Liushui Yan,Kexin Li,Huiqin Guo,Wang Gong,Jun Lin
In this work, a series of Zn x Cd 1-x S solid solutions are firstly prepared by a solvothermal process. The optimized composition of Zn x Cd 1-x S solid solution is determined to be Zn 0·2 Cd 0.8 S. On this basis, the Cu 7 S 4 /Zn 0·2 Cd 0·8 S composite photocatalyst with a binary p-n heterojunction has been synthesized by a co-precipitation process followed by a solvothermal method . Owning to the synergistic effect of the heterojunction structure in the interface of Cu 7 S 4 (p-type) and Zn 0·2 Cd 0·8 S (n-type) and the built-in electric field in binary p-n heterojunction, the as-prepared Cu 7 S 4 /Zn 0·2 Cd 0·8 S composite photocatalyst exhibits a significantly improved photocatalytic activity toward hydrogen production from water with visible light response, which is approximately 5.0 times and 16.5 times higher than of pristine Zn 0·2 Cd 0·8 S and CdS, respectively. The possible photocatalytic mechanism has been proposed basing on a series of experimental results. The current work might be valuable inspirations for designing highly efficient heterojunction composite photocatalyst for solar hydrogen evolution .
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Journal of Flow Chemistry
·
2022
·Vol. 12
·期 3
·317-325
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IF 3.264
Xu Qilin,Li Guosi,Zhu Fucheng,Chen Naidong,Chen Cuiwu,Yu Zhiqun
N -(3-Amino-4-methylphenyl)benzamide ( 1 ) is a crucial building blocks of many drug candidates. In this paper, a continuous flow microreactor system was developed to synthesize 1 and determine intrinsic reaction kinetics parameters. By screening the acylating reagents and reaction conditions, 1 was obtained by the selective acylation of 4-methylbenzene-1,3-diamine ( 2 ) with benzoic anhydride ( 3 ). Since the two amine groups in 2 are in different chemical environments, parallel by-products and serial by-products coexist, which makes the selective monoacylation process relatively complicated. To reveal the reaction process clearly, reaction rate constants and their 95% confidence intervals, activation energies, pre-exponential factors were acquired by kinetics study in microflow system. The established kinetic model can calculate the selectivity and conversion of the acylation reaction, which are in good agreement with the experimental results. Subsequently, the kinetic model was used to optimize reaction conditions, as a result, 1 was synthesized in the microreactor with a yield of 85.7% within 10 min.
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FUEL
·
2022
·
IF 8.035
Xiang Lv,Yi Gao,Yueshuai Cui,Chen Wang,Gangchui Zhang,Fang Wang,Peijin Liu,Wen Ao
The ignition and combustion properties of n -Al/CuO/kerosene nanofluid fuels are examined, with a focus on the formulation effects of the n -Al/CuO nano-thermite. The DSC data shows the addition of CuO facilitates the exothermic process of n -Al particles, which then promote the n -Al/CuO/kerosene droplets to evaporate. There are two exothermic peaks on the DSC curve of n -Al/CuO (5 %) at 249.3 ℃ and 463.8 ℃, respectively. The burning of n -Al/CuO/kerosene droplets consists of four stages: ignition, d 2 -law combustion, vapor flame extinguishment, and agglomerate burning. During the agglomerate burning stage, n -Al/CuO (5 %)/kerosene shows the minimum ignition delay at 0.057 s and the highest emission spectral intensity. Droplet combustion conforms well to the d 2 -law, and the maximum combustion rate is found for n -Al/CuO (20 %)/kerosene, at 1.287 mm 2 s −1 . The particle size of combustion residues is uniform, and the overall appearance smoothens as the CuO content increases. A new nanofluid fuel with better ignition and combustion properties than traditional nanofluid fuels is proposed.
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ENERGY & FUELS
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2022
·
IF 4.654
Xing Yin,Junjie Shao,Wenbiao Zhang,Qingsheng Gao
Cost-efficient electrocatalysts derived from earth-abundant resources are urgently demanded for sustainable hydrogen production from water electrolysis. Here, biomass kapok fibers (KFs) are introduced to fabricate Mo2C@N, P co-doped carbon (Mo2C@NPC) core@shell electrocatalysts that are highly active for acidic and alkaline hydrogen evolution reaction (HER). After facile prestabilization in the presence of (NH4)2HPO4 and subsequent carbonization under an inert flow, naturally available kapok fibers convert to hollow carbon microtubes with N, P co-doping, which afterward serve as the self-template and support to obtain ultrafine Mo2C nanoparticles encapsulated by N, P co-doped carbon shells. Such shells not only boost the HER performance due to the optimized electronic configuration and the promoted conductivity but also protect Mo2C from corrosive electrolytes and result in satisfactory long-term durability. In 1.0 M HClO4 and 1.0 M KOH, Mo2C@NPC exhibits excellent performance among recently reported electrocatalysts free from noble metals, featured by low overpotentials of 127 and 155 mV at the current density of −10 mA cm–2 and the Tafel slope of 63 and 64 mV dec–1, respectively. The long-term durability of Mo2C@NPC can be confirmed by both accelerated degeneration and chronoamperometric tests. Elucidating efficient electrocatalysis on biomass-derived nanomaterials, this work will inspire further exploration of efficient electrocatalysts.
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Water
·
2022
·Vol. 14
·期 14
·2248
·
IF 3.53
Guowei Pang,Min Ji,Zhuoran Li,Zhengwu Yang,Xiaojie Qiu,Yingxin Zhao
In this work, an efficient cage-core peroxymonosulfate (PMS) catalyst was synthesized by applying an electrospinning–calcination process to the cobalt–zeolitic imidazole framework (ZIF-67) crystals for the catalytic degradation of dimethyl phthalate (DMP). The morphology and surface properties of the synthesized materials (ZIF-67, Z600 and ZP400/600/800) were well characterized. ZP600 showed great performance for the catalytic degradation of DMP in the initial pH range of 7.5–10.5. The removal rate of DMP could reach 90.4% in 60 min under optimum dosages of reagents (catalyst = 0.1 g/L, PMS = 0.5 mM, DMP = 6 ppm), and the mineralization degree of contaminant could reach 65%. By quenching experiments, it was determined that sulfate radical (SO4−·) and hydroxyl radical (·OH) dominated the degradation process. Moreover, due to the good magnetism, ZP600 could be easily separated from liquid and showed great reusability in five-cycle reaction experiments. Surprisingly, with the cover of cage-like polyacrylonitrile (PAN) fibers, the cobalt leaching amount of ZP600 decreased by about 87%. This study would expand the application of the electrospinning process in the development of functional materials for water purification.Keywords:elctrospinning;ZIF-67;peroxymonosulfate;cobalt leaching control
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Biomass Conversion and Biorefinery
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2022
·Vol. 13
·期 18
·17247-17254
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IF 4.05
Wang Wei,Zhang Zhe,Wang Min
The electrochemical catalytic oxidation of 5-hydroxymethylfurfural (HMF) derived from biomass to produce 2,5-furandicarboxylic acid (FDCA) has attracted significant attention. Herein, the catalyst NiO-N/C composite was prepared and showed high activity for the electrochemical oxidation of HMF. The optimized NiO-N/C composite electrode supported by foamed nickel exhibits 99% conversion of HMF, 84% yield of FDCA, and 96% faradic efficiency. The NiO-N/C composite electrode is stable and remains active after six consecutive measurements. This work provides an effective method for the design and preparation of biomass energy electrocatalysts based on nitrogen-modulated NiO materials.
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NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 27
·12934-12940
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IF 3.925
Hansen Yang,Zhimiao Wang,Hualiang An,Qiusheng Yang,Wei Xue,Fang Li,Yanji Wang
Theobromine is an important pharmaceutical intermediate and food additive. We have developed a green method for theobromine synthesis, namely catalyst-free methylation of 3-methylxanthine with dimethyl carbonate (DMC). The effects of various solvents on the reaction were investigated; H2O was found to be the most appropriate solvent. The bond energies of C–O in DMC and N–H in 3-methylxanthine were calculated at the M06-2x/6-311G(d,p) level, and the role of the solvent was examined theoretically. The use of H2O as the solvent and the effects of DMC hydrolysis on the reaction were investigated. The results show that DMC hydrolysis was, to some extent, beneficial to theobromine synthesis. The reaction conditions were optimized. When the molar ratio of DMC to 3-methylxanthine was 11 : 1 and the 3-methylxanthine dosage was 0.1 g per mL-H2O, reaction at 160 °C for 9 h gave a 3-methylxanthine conversion of 89.9% with 98.2% theobromine selectivity.
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CELLULOSE
·
2022
·Vol. 29
·期 14
·7823-7836
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IF 6.123
Yuan Zhengqiu,Dai Wei,Li Xiaoyan,Wu Yangfeng,Zang Kairong,Zeng Jianxian,Jian Jian,Zhou Hu
Cellulose acetate (CA) was used for the preparation of food packaging film. Glycerol and n-propanol were introduced, as plasticizer and transparent agent, respectively for evaluating the possible changes of the film functional properties on tensile strength and transparency. The transmittance, haze value, tensile strength and flexibility were acquired by using optical and mechanical analyses, respectively. The presence of glycerol improved the functional properties of films by increasing their extensibility, flexibility and elasticity; however transparency of the films deteriorated with the inclusion of plasticizer. Therefore, the addition of n-propanol as transparent agent into the films enhanced the transparency. Moreover, morphological changes and gas barrier property were confirmed by scanning electron microscopy and water vapor transmission rate analyses. The results suggest that CA films incorporated with plasticizer and transparent agent have good functional properties in isolating water vapor, mechanical performance and optical properties, demonstrating that the optimal film has a potential in the application for food packaging. Graphical abstract
High strength transparent cellulose acetate film (CAF) was prepared with glycerol as plasticizer and n-propanol as transparent agent. The addition of glycerol and n-propanol has a significant influence on film mechanical performance, optical properties, water vapor barrier property and physical behavior, such as pore structure.
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POLYMERS FOR ADVANCED TECHNOLOGIES
·
2022
·Vol. 33
·期 10
·3490-3500
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IF 3.348
Wu Zhang,Weikang Xia,Yasheng Shi,Changlin Zhou,Ran Chen,Lei Wang,Jinqing Qu
Flame-retarded epoxy thermosets are highly desirable for electronics-related basic materials in the new-generation information applications. Herein, a DOPO-anchored benzothiadiazole flame retardant, namely DOPO-BTD , is designed and synthesized for P/N/S synergistic flame-retarded epoxy thermosets. DOPO-BTD possesses good thermal stability and excellent compatibility with the epoxy matrix. As reflected by UL 94 test, the DOPO-BTD coated EP passes the V0 rating and achieves a higher LOI value of 34.6% at ultralow P content of 0.39 wt%. The investigation of the DOPO-BTD -triggered P/N/S synergistic flame-retarded effect by thermal images further validated the flame retarded efficacy and dramatic inhibition of the flame. Meanwhile, the incorporation of 4.8 wt% DOPO-BTD into the epoxy matrix, the PHRR, THR, SPR, TSP, and COP are significantly decreased by 37.97%, 27.44%, 25.49%, 19.83%, and 31.70%, respectively. Additionally, the fire growth index (FGI) is sharply dropped 26.06%. Moreover, the TGIR and TGMS results convince the flame-retarded mechanism of DOPO-BTD through the combination of the gas-phase and condensed-phase pathways. The P/N/S synergistic DOPO-BTD can serve as a promising flame retardant for efficiently fabricating the flame-retarded epoxy thermosets, and this study sheds light on the development of multiple elements synergistic flame-retardants for functional polymers with great application potential.
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LANGMUIR
·
2022
·
IF 4.331
Changsheng Sun,Shujing Zhou,Jinjing Li,Chenze Qi,Yong Gao
Nonaqueous Pickering emulsions exhibit promising applications in many industrial areas but have been relatively less studied in the past. In this study, n-hexane-in-DMF nonaqueous Pickering emulsions stabilized by core cross-linked copolymer worms with mixed shells are demonstrated for the first time. Core cross-linked copolymer worms with mixed shells were prepared by seeded reversible addition–fragmentation chain transfer (RAFT) quasi-solution polymerization. Specifically, polystyrene-poly(4-vinylpyridine) (PS-P4VP) diblock copolymer worms were first prepared via RAFT-mediated dispersion polymerization in toluene under the given conditions using PS as both the macro-CTA and the stabilizer block. After the chemical cross-linking of P4VP cores, PS-P4VP diblock copolymer worms were chain-extended with LMA in DMF/toluene (1:9, weight ratio) mixed solvents, producing core cross-linked PS-P4VP-PLMA worms with PS/PLMA mixed shells. The as-prepared core cross-linked PS-P4VP-PLMA worms with mixed PS/PLMA shells were further utilized as Pickering emulsifiers for the generation of nonaqueous n-hexane-in-DMF Pickering emulsions. The emulsifying performances of mixed-shell copolymer worms were compared with those of their spherical and linear analogues with entirely identical chemical compositions as well as PS-P4VP diblock copolymer worm precursors, respectively.
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PubMed
高影响因子
MOLECULES
·
2022
·Vol. 27
·期 15
·4720
·
IF 4.927
Xinjun Yu,Zengchao Jiang,Xiaodan Xu,Changyi Huang,Zheyi Yao,Xiao Yang,Yinjun Zhang,Dongsheng Wang,Chun Wei,Xuwei Zhuang
Chitin, the second richest polymer in nature, is composed of the monomer N-acetylglucosamine (GlcNAc), which has numerous functions and is widely applied in the medical, food, and chemical industries. However, due to the highly crystalline configuration and low accessibility in water of the chitin resources, such as shrimp and crab shells, the chitin is difficult utilize, and the traditional chemical method causes serious environment pollution and a waste of resources. In the present study, three genes encoding chitinolytic enzymes, including the N-acetylglucosaminidase fromOstrinia furnacalis(OfHex1), endo-chitinase fromTrichoderma viride(TvChi1), and multifunctional chitinase fromChitinolyticbacter meiyuanensis(CmChi1), were expressed in thePichia pastorissystem, and the positive transformants with multiple copies were isolated by the PTVA (post-transformational vector amplification) method, respectively. The three recombinants OfHex1, TvChi1, and CmChi1 were induced by methanol and purified by the chitin affinity adsorption method. The purified recombinants OfHex1 and TvChi1 were characterized, and they were further used together for degrading chitin from shrimp and crab shells to produce GlcNAc through liquid-assisted grinding (LAG) under a water-less condition. The substrate chitin concentration reached up to 300 g/L, and the highest yield of the product GlcNAc reached up to 61.3 g/L using the mechano-enzymatic method. A yield rate of up to 102.2 g GlcNAc per 1 g enzyme was obtained.Keywords:chitinase;shrimp and crab shell;N-acetylglucosamine;mechanoenzymology;heterologous expression
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危险品化学品经营许可证（带存储）