Journal of the Taiwan Institute of Chemical Engineers
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2022
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IF 5.477
Binxiong Guang,Yiwei Zhang,Yahui Xiao,Miaojun Su,Xiying Li,Yong Liu
Background It is of great significance but still a challenge in the chemical industry to develop high-efficient heterogeneous catalysts for selective oxidation of styrene into benzaldehyde with molecular oxygen. Methods Fe 3 C nanoparticles confined in N-doped carbons (Fe 3 C/NC) were prepared using Fe 3+ coordinated N-bearing ionic liquids as precursors and melamine as nitrogen source and template, followed by pyrolysis at 900 °C under N 2 atmosphere. The physicochemical properties of the as-prepared Fe 3 C/NC catalyst were analyzed by FT-IR, TG, BET, TEM, XRD, Raman and XPS, respectively, and further employed as novel heterogeneous catalyst for selective oxidation of styrene into benzaldehyde with molecular oxygen. Significant findings The results showed that the Fe 3 C nanoparticles were formed and uniformly embedded into the N-doped carbon matrix, which were confirmed to be the active sites for styrene oxidation. Moreover, the 5 % Fe 3 C/NC catalyst possessed high surface area and dominant mesoporous structure, which could expose more accessible active sites and facilitate mass transfer. As a result, the 5 % Fe 3 C/NC catalyst exhibited superior catalytic performance for styrene oxidation into benzaldehyde with the appropriate styrene conversion of 58.8 % and selectivity to benzaldehyde of 64.1 % as well as no significant activity and selectivity loss after reused at least five times.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2021
·Vol. 138
·期 37
·50949
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IF 3.125
Fan Kong,Xueli Jia,Shuting Zhang,Mengqi Lin,Yu Cheng
We have synthesized an amphiphilic block copolymer poly(N-isopropylacrylamide)- b -poly(N-vinylcarbazole) containing 1,8-naphthalimide and spirolactam rhodamine 6G moieties via reversible addition-fragmentation chain transfer radical polymerization. The photoluminescence (PL) spectrum of the poly(N-vinylcarbazole) block well matches the absorption spectrum of the 1,8-naphthalimide moiety and the enhanced emission with a peak at 510 nm from the 1,8-naphthalimide moiety is found in the block copolymer film for excitation at 330 nm. The 560-nm emission from the rhodamine 6G moiety is observed as the block copolymer film sprayed by Britton-Robinson (B-R) buffers or Fe 3+ aqueous solutions for excitation at 330 and 400 nm. The PL intensity at 560 nm is markedly increased for the pH value of the B-R buffer lower than 3.0 or the Fe 3+ concentration in water higher than 5 × 10 −4 M. The 560-nm PL intensity is much higher for the block copolymer film photoexcited at 330 nm than that photoexcited at 400 nm due to double-step resonance energy transfer. The PL intensity ratio of 560 to 510 nm (I 560 /I 510 ) is dependent on the resonance energy transfer from 1,8-naphthalimide to rhodamine 6G, which is sensitive to the concentrations of H + and Fe 3+ ions in water.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2020
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IF 2.369
Guang Yang,Jianqiang Zhang,Suhua Yu,Chunjuan Huang,Xin Song,Renjie Xu
Water as an auxiliary solvent is added to various alcohol solvents (methanol, ethanol, ethylene glycol (EG)) and N,N-dimethylformamide (DMF) to form a variety of liquid mixtures, which are divided into different types according to different proportions. Starting from pure water, 0.1 mass fraction of organic solvents is added at a time, until the ratio of organic solvent is 1. The above-mentioned liquid mixtures are used as solvents to dissolve rimsulfuron at 278.15–323.15 K under 101.1 kPa by means of the isothermal static technique. Considering that there are many factors that change the experimental results, this experiment mainly selected temperature and water content, two factors, as the main independent variables. From the point of view of temperature, it changes from a low value to a high value, so it is obvious that the solute mole fraction also follows its footsteps. Unlike the temperature, as the organic solvent is continuously diluted by water, the solute solubility changes in the opposite direction to the water content. By controlling the variable method to ensure that the above two variables remain unchanged, DMF has the best dispersion ability for all of the selected solvents to dissolve rimsulfuron. The dissolution strength of the selected solvents at 323.15 K obeyed the following ascending sequence: EG (3.192 × 10–5) < ethanol (8.497 × 10–5) < methanol (9.849 × 10–5) < DMF (2.622 × 10–4). We employed Jouyban–Acree, van’t Hoff–Jouyban–Acree, and a combination of the Apelblat–Jouyban–Acree model to calculate solubility values of rimsulfuron. Results of relative average deviation (RAD) and root-mean-square deviation (RMSD) from the van’t Hoff–Jouyban–Acree model were 2.11% and 1.50 × 10–6, respectively. For drugs with poor water solubility and dissolution rate, measuring their solubility and understanding their dissolution properties can effectively help solve the problem of nonwetting and nondiffusion.
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ENERGY
·
2020
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IF 6.082
Yan Wang,Dong-Liang Zhong,Peter Englezos,Jin Yan,Bin-Bin Ge
The kinetics of semiclathrate hydrates formation with CO 2 in the presence of tetra- n -butyl ammonium bromide (TBAB), tetra- n -butyl phosphonium bromide (TBPB), and TBAB + TBPB were investigated. The experiments were conducted at the stoichiometric concentration of TBAB hydrate (2.57 mol%) and three subcoolings (Δ T = 6 K, 9 K, and 12 K) with the initial pressure fixed at 2.8 MPa. It was found that adding TBPB into the TBAB solution can promote hydrate nucleation, and this promotion effect at a lower subcooling (Δ T = 6 K) was stronger compared to that at higher subcoolings (Δ T = 9 K and 12 K). The gas consumption obtained in TBAB, TBPB, and TBAB + TBPB solutions decreased with the increase of subcooling, despite the increase of the rate of hydrate growth. At a given subcooling, gas consumption (CO 2 uptake) in TBAB + TBPB solutions was greater than that in TBAB and TBPB solutions, indicating that hydrate formation kinetics and the CO 2 storage capacity were improved in the TBAB + TBPB solution. The largest gas consumption was obtained at Δ T = 6 K in the TBAB + TBPB solution, which was 28.7% and 17.2% larger than those obtained in TBAB and TBPB solutions, respectively. Therefore, a mixture of TBAB + TBPB is a promising option to improve the kinetics of semiclathrate hydrate formation with CO 2 .
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ACS Omega
·
2023
·
IF 4.1
Wanru Gao,Yuping Li,Yunping Zhoujin,Qun Zeng,Liwen Fang,Sean Parkin,Tonglei Li,Shigang Ruan,Sihui Long
Four 2-hydroxy-N-alkyl-N-phenyl-nicotinamides (1–4) were synthesized, and their crystal structures were analyzed to investigate the effect of substitution on their crystal packing of N-phenyl-2-hydroxynicotinanilides. In these compounds, substituents were introduced on the amide N, leading to a peptoid-like structure. One solvent-free form and two hydrates were harvested for compound 1, and one anhydrous form and one hydrate were obtained for compound 2. Polymorphism was observed in compounds 3 and 4. The molecules were found to be in the keto form rather than the enol tautomer. Because of steric effects, the molecules took on an E configuration, leading to a hairpin-like geometry. A lactam–lactam dimer synthon was formed in all solvent-free structures, and a tetramer motif was observed for the first time. Dehydration of the two hydrates of 1 and the hydrate of 2 led to their respective solvent-free form. Phase transition between the polymorphs was revealed in compound 3. Theoretical calculations, including conformational energy evaluation, hydrate forming propensity assessment, and lattice energy appraisal, were performed to provide a reasonable explanation for the keto tautomer and the formation of the hydrates of compound 1.
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Journal of Cleaner Production
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2023
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IF 11.1
Qingwen Fan,Chaoyun Song,Peng Fu
The widespread proliferation of modern portable electronic devices has necessitated the development of functional materials with high-efficiency microwave absorption properties. In this study, we utilized biomass-derived jujube shells as a carbon source and employed a nitrogen-doping process to modify carbon materials, resulting in the fabrication of outstanding microwave-absorbing biomass-based nitrogen-doped porous carbon. Additionally, we discussed the influence of different nitrogen sources on material structure and microwave absorption performance. These N-doped porous carbon materials exhibited excellent specific surface areas, particularly Org-N, which facilitated the formation of conductive networks and the multi-stage reflection and scattering of microwave. Moreover, N-doping created numerous defect sites and heterogeneous structures, improving impedance matching , thus promoting dipole polarization and interface polarization effects , which accelerated electron migration and interlayer hopping, contributing to the attenuation of microwave energy. The lowest reflection loss for Org-N, Inorg-N, and Mixed-N reached −27.3 dB, −40.9 dB, and −45.6 dB, respectively. Mixed-N exhibited optimal microwave absorption performance at 9.9 GHz with d = 2.4 mm and achieved an effective absorption bandwidth (EAB 10 ) of 3.0 GHz (11.0 GHz–14.0 GHz) at d = 2.0 mm. Additionally, the enhancement of polarization relaxation effects was elucidated by examining the charge density distribution in molecular models featuring various N-doping forms. Consequently, biomass-derived N-doped porous carbon materials emerge as lightweight and highly efficient functional materials for microwave absorption purposes.
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CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Ying Liu,Wei Miao,Xian Fang,Yulin Tang,Deli Wu,Shun Mao
The development of metal-free catalysts with high activity and stability for persulfate activation draws increasing attention due to their promising performance and environmental benignity. Herein, hierarchically porous nitrogen (N)-doped carbon (N C) with merits of highly-dispersed nitrogen, large surface area and controllable structure is synthesized. The as-prepared N C exhibits outstanding performance for peroxydisulfate activation in the degradation of diverse organic pollutants, as well as a wide working pH range of 3–10. Impressively, an annealing strategy can regulate C O and graphitic N contents in N C and their quantitative correlations with the reaction rate constants reveal that the C O and graphitic N in N C are active sites. Furthermore, peroxydisulfate activation by N C involves with three pathways in which the contribution from radicals (SO 4 − , OH) are comparatively weak and non-radical pathways including singlet oxygen ( 1 O 2 ) and electron transfer are dominant. The contribution of 1 O 2 is diminishing with delay of reaction while the electron transfer shows the opposite trend. Besides, good recycling performance is achieved by facile re-annealing of N C. This work provides new insights into the reaction mechanism of persulfate catalysis and can guide future catalyst development in advanced oxidation process.
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POLYMER INTERNATIONAL
·
2018
·Vol. 67
·期 5
·535-543
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IF 2.352
Yang Hu,Lihui Wang,Jie Shen,Guoqiang Jiang,Chengyou Kan
Using styrene (St) and N , N ′-dimethylaminoethyl methacrylate (DMAEMA) as raw materials, monodispersed P(St- co -DMAEMA) nanoparticles (NPs) were first prepared via semi-continuous emulsion polymerization, and using a stepwise acid–alkali post-treatment, porous P(St- co -DMAEMA) NPs were then obtained and used to adsorb heavy metal ions in aqueous phase. Results showed that the post-treatment conditions including temperature, initial pH and time of acid–alkali treatment had significant effects on the morphology of the porous P(St- co -DMAEMA) NPs, with higher temperature, more extreme pH condition and longer treatment time resulting in larger pores and volume swelling ratio. Under the optimized acid–alkali post-treatment conditions (60 °C, acid treatment at pH = 4.0 for 1 h and then alkali treatment at pH = 10.0 for 1 h), the obtained porous NPs had nearly 15 times the surface area and 1.5 times the amount of surface amino groups than the corresponding solid NPs. An analysis of the mechanism of metal ion adsorption on the porous NPs indicated that the adsorbed amount of metal ions was the result of synergistic effect of physical and chemical adsorption, which was closely related to the porous NP surface area, amount of surface of amino groups and the volume of the ions. © 2018 Society of Chemical Industry
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2018
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IF 2.196
Yitong Dai,Wenqi Zhao,Haiyun Sun,Yongsheng Guo,Wenjun Fang
Densities (ρ) and viscosities (η) of ternary system n-dodecane + bicyclohexyl + n-butanol and three corresponding binary systems, n-dodecane + bicyclohexyl, n-dodecane + n-butanol, and bicyclohexyl + n-butanol, were measured at temperature range from 293.15 to 333.15 K in detail. Densities were obtained using a vibrating-tube densimeter. Viscosities were determined using an automatic microviscometer based on the rolling ball principle. The excess molar volumes (VmE) and the viscosity deviations (Δη) of each mixture were calculated with the measured data. The VmE and Δη values of three binary systems were fitted to the Redlich–Kister equation, and those of the ternary system were fitted to Nagata–Tamura, Singh, Clibuka, and Redlich–Kister semiempirical equations. The VmE values are negative for the binary system of n-dodecane + bicyclohexyl with the minimum at about x = 0.5, while those of binary systems n-dodecane + n-butanol and bicyclohexyl + n-butanol are positive over the entire concentration range. For the ternary system, the VmE values are subtotal positive and the Δη are negative over the entire concentration range. The nonideal behaviors of the mixtures are explained by physical interactions and structural effects between mixture components.
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Catalysts
·
2018
·Vol. 8
·期 5
·188
·
IF 3.465
Dalei Sun,Kaihong Xie,Yanxiong Fang,Xianghua Yang
One-pot synthesis ofN,N′-dialkylureas were successfully achieved from catalytic carbonylation of aliphatic primary amines with CO2as the carbon source and Y0.08Zr0.92O1.96mixed oxide (Yttria-stabilized zirconia, YSZ-8) as the heterogeneous catalyst. The yield of the target product was obtained up to 80.60% from a 48 h reaction with an aliphatic primary amine and 3.0 MPa CO2inN-methyl-2-pirrolidinone at 160 °C. A multi-pronged mechanistic study was carried out where factors that might influence the reaction efficiency were studied, including catalyst structure, substrates basicity, CO2pressure, solvent polarity and reaction time. The presence of oxygen vacancies in YSZ-8 was found to be essential for the carbonylation process by creating additional reduction potential for the activation of CO2which would lead to the key intermediate species.Keywords:Y0.08Zr0.92O1.96mixed oxide;N,N′-dialkylurea;carbonylation;CO2;heterogeneous catalysis
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ENVIRONMENTAL POLLUTION
·
2018
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IF 4.358
Shuyan Zhao,Bohui Wang,Lingyan Zhu,Tiankun Liang,Meng Chen,Liping Yang,Jingping Lv,Lifen Liu
N-ethyl perfluorooctane sulfonamide (N-EtFOSA) is commonly known as the active ingredient of sulfluramid. It can be degraded to perfluorooctane sulfonic acid (PFOS) in biota and environment. Earthworms ( Eisenia fetida ) were exposed with N-EtFOSA to examine the bioaccumulation, elimination and metabolism of N-EtFOSA by the earthworms after in vivo and in vitro exposure. N-EtFOSA could be biodegraded in quartz sands to perfluorooctane sulfonamide (FOSA) and PFOS. In the in vivo tests, in addition to parent N-EtFOSA, three metabolites, including perfluorooctane sulfonamide acetate (FOSAA), FOSA and PFOS also accumulated in earthworms as a result of N-EtFOSA biotransformation , with FOSA as the predominant metabolite. The bioaccumulation factor (BAF) and uptake rate coefficient ( k u ) of N-EtFOSA from sand were 20.4 and 2.41·d −1 , respectively. The elimination rate constants ( k e ) decreased in the order FOSAA (0.130·d −1 ) > N-EtFOSA (0.118·d −1 ) > FOSA (0.073·d −1 ) > PFOS (0.051·d −1 ). The biotransformation of N-EtFOSA in earthworm was further confirmed by the in vitro test involving incubation of earthworm homogenates with N-EtFOSA. This work provides evidence on the accumulation and transformation of N-EtFOSA in terrestrial invertebrates and will be helpful to explore the indirect sources of FOSA and PFOS in environmental biota.
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JOURNAL OF FOOD SCIENCE AND TECHNOLOGY-MYSORE
·
2024
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IF 2.6
Zhu Jie,Zhang Hua-nan,Wu Jia-kai,Li Fei-fei,Liu Yu-qing,Ning Er-juan,Yu Li-qin,Liang Shen
Camelina sativa oil (CSO) and Semen Ziziphi Spinosae oil (SZSO) are functional oils that have beneficial effects on brain health. This study evaluated the sedative and hypnotic effects of vegetable oils with various n − 6/n − 3 polyunsaturated fatty acids (PUFA) ratios and ɑ-linolenic acid (ALA) contents to mice. The n − 6/n − 3 PUFA ratios of CSO (CSO:SZSO = 1:0, 1.8 g/kg), SZSO (CSO:SZSO = 0:1, 1.8 g/kg), CSO-SZSO-L (CSO:SZSO = 1:1, 1.8 g/kg), and CSO-SZSO-H (CSO:SZSO = 1:1, 3.6 g/kg) were 0.51, 140, 1.69, and 1.69, respectively. The doses of ALA administered to mice with p-chlorophenylalanine-induced insomnia were approximately 0.64, 50 × 10 –4 , 0.32, and 0.64 g/kg, respectively. The mice were administered CSO, SZSO, and a low-dose combination of CSO and SZSO for seven days with no obvious hypnotic effects. However, the administration of a high-dose combination of CSO and SZSO significantly prolonged sleep duration in mice with induced insomnia and inhibited the serum levels of corticotropin-releasing hormone, adrenocorticotropic hormone, and cortisol. Interestingly, there were no significant effects on the structure and function of the hippocampal tissue. The results indicated that the anti-insomnia effects of these vegetable oils were positively correlated with a low n − 6/n − 3 PUFA ratio and the absolute amount of ALA.
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