INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2019
·
IF 3.375
Guangyuan Zhao,Danxin Hu,Shenghu Zhou,Jian Zhang,Lei Wang
A series of supported highly dispersed CuNi alloy nanocatalysts were fabricated by a coprecipitation method for the N-alkylation of aniline with 2,5-dihydroxymethylfuran under base-free conditions. Various characterizations and catalytic experiments were carried out to systematically investigate the relationship between the catalytic performance and synthetic parameters, such as calcination temperatures, reduction temperatures, and catalyst compositions. The optimized Cu3/17Ni6/17Al8/17O catalysts show good selectivity for the N-alkylation of aniline with 2,5-dihydroxymethylfuran under mild reaction conditions. This work broadens the application of non-noble bimetallic nanocatalysts for N-alkylation reactions and opens new opportunities to synthesize useful HMF derivatives and other valuable biobased chemicals.
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JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A
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2019
·Vol. 107
·期 7
·1532-1540
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IF 3.221
Mingchen Zhou,Fei Xie,Guocang Li,Qiyang Wang,Longxiang Tang,Manqing Yan,Hong Bi
The trinary hydroxyapatite@Fe 3 O 4 @N-doped carbon dots (HA@Fe 3 O 4 @N-CDs) hybrids were prepared by one-pot hydrothermal approach and utilized to detect and remove lead ion from aqueous solution. The structures and morphologies of as-obtained nanorod-like HA@Fe 3 O 4 @N-CDs hybrids were characterized by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy measurements. These HA@Fe 3 O 4 @N-CDs hybrids possess good magnetism by magnetic hysteresis test and multi-colored fluorescence by the CLSM measurement. Furthermore, the as-obtained hybrids display excellent biocompatibility by MTT assay. Importantly, the trinary magnetic HA@Fe 3 O 4 @N-CDs hybrids as a green detector and adsorbent of Pb 2+ were investigated. The influence of the different pH, the concentration of heavy metal, and the maximum adsorption capacity on removal efficiency was measured in detail. The maximum Pb 2+ adsorption capacity on HA@Fe 3 O 4 @N-CDs hybrids is 450 mg/g. The kinetic mechanism was a pseudo-second order model, and the isotherm data was fitted well by the Langmuir isotherm and Freundlich model. Hence, the nanorod-like HA@Fe 3 O 4 @N-CDs hybrids could be a multifunctional material with significant potential applications in heavy metal detection and adsorption, bone tissue regeneration, magnetic therapy, and biomedicine. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2019.
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Polymer Chemistry
·
2018
·Vol. 10
·期 5
·656-662
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IF 4.927
Qi-Song Tong,Wei Xu,Qiu-Yue Huang,Ya-Ru Zhang,Xiao-Xiao Shi,Hua Huang,Hong-Jun Li,Jin-Zhi Du,Jun Wang
A novel type of multi-stimuli responsive dendrimer with thermo-, pH-, and CO2-responsiveness was developed through facile modification of polyamidoamine dendrimers (PAMAM) with various N-dialkylaminoethyl carbamate moieties. A series of modified PAMAM dendrimers with a well controlled structure were obtained and characterized by 1H NMR. The aqueous solutions of these dendrimers showed a lower critical solution temperature (LCST)-type thermoresponse, and their cloud point temperature (Tcp) was determined by turbidity measurements. Tcp was tunable from 8 to 70 °C, depending on the hydrophobicity and substitution number of the terminal N-dialkylaminoethyl groups, PAMAM generation, pH values, and salt concentrations. Additionally, the solubility of the resultant dendrimers could be reversibly modulated by alternately bubbling CO2 and argon. Our study offers a simple but effective approach to making new multi-stimuli responsive dendrimers for potential smart material applications.
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POLYMER INTERNATIONAL
·
2019
·Vol. 68
·期 10
·1673-1680
·
IF 2.433
Jiahui Su,Yan Yang,Zhikang Chen,Junyi Zhou,Xiaoxuan Liu,Yanxiong Fang,Yanyan Cui
In this study, frontal photopolymerization was applied to the fabrication of thermosensitive poly( N -isopropylacrylamide) (PNIPAm) hydrogels. The influence of experimental conditions and reactant components on the feature of the polymerization front was investigated. The morphology of the samples indicated the successful preparation of PNIPAm hydrogels. The mechanical properties and thermal stability of the obtained hydrogels are discussed. The results indicated that the performance of the hydrogels is related to their microstructure and the type of crosslinkers. The swelling behavior and drug delivery ability were determined under different temperature conditions. The hydrogels exhibit a classical thermoresponsive behavior, which was also demonstrated by the DSC results. Therefore, frontal photopolymerization can be an alternative method for the preparation of PNIPAm hydrogels under mild conditions. © 2019 Society of Chemical Industry
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JOURNAL OF CHEMICAL THERMODYNAMICS
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2019
·
IF 2.29
Daofan Ma,Qing Liu,Chunying Zhu,Huisheng Feng,Youguang Ma
The densities and viscosities of binary solutions of (N-methyldiethanolamine + ethanol), (monoethanolamine + ethanol) and (N-methyldiethanolamine + monoethanolamine) as well as ternary solution of (N-methyldiethanolamine + monoethanolamine + ethanol) were measured at T = 293.15 K, 303.15 K, 313.15 K, 323.15 K. The volumetric and viscometric properties, such as the excess molar volume V E , the partial molar volume V ¯ , the partial molar volume at infinite dilution V ¯ ∞ and the viscosity deviation Δ η , were calculated from the experimental densities and viscosities. The excess molar volumes and viscosity deviations of binary and ternary solutions were correlated by the Redlich-Kister equation and the Cibulka’s equation, respectively. The intermolecular interactions in binary and ternary solutions were analysed.
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APPLIED CATALYSIS A-GENERAL
·
2019
·
IF 4.63
Yihu Dai,Chunyang Jiang,Min Xu,Bo Bian,Di Lu,Yanhui Yang
Anilines as important intermediates for both organic synthesis and industrial manufactory are densely substituted with a variety of functional moieties, and the transformation of nitroarenes into corresponding anilines requires catalytically selective hydrogenation catalyst. Herein, we describe a simple pyrolysis strategy to prepare cobalt catalysts in nitrogen-doped carbon matrix applied in the selective hydrogenation of nitroarenes with molecular hydrogen. The Co/NC catalysts are obtained through thermal treatment of mixed precursors of cobalt phthalocyanine and melamine . The surface-modified Co particles with Co 3 O 4 and CoN x sites are surrounded by N-doped carbon layers according to a series of structural characterization results. These Co/NC catalysts are capable of efficiently selective hydrogenation of nitrobenzene and various substituted nitroarenes into corresponding anilines under relatively mild reaction conditions. The optimal catalytic hydrogenation performance is contributed to the fast rate of H 2 dissociated activation on the CoN x active sites and the facile adsorption of the reactant substances, which is verified by the isotopic H 2 -D 2 exchange experiments, reactant adsorption and the ORR reaction tests. Furthermore, the heterogeneous Co/NC catalyst is highly stable without the Co leaching and deactivation issues during the recycling reaction runs.
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Materials Research Express
·
2019
·Vol. 6
·期 8
·085020
·
IF 1.449
Hexi Zhao,Yan Wu,Hui Nan,Yonglong Du,Guijun Yang,Gang Wang,Huiyuan Chen,Haomin Wei,Hong Lin
TiO2-ZnO, TiO2-Fe2O3, TiO2-NiO binary heterojunction nanocomposites were synthesized by hydrothermal method using tetrabutyl titanate (TBT) as titanium source. Phase composition, microscopic shape ,functional group characteristics and optoelectronic properties of samples were characterized by x-ray diffractometry (XRD), transmission electron microscopy (TEM), photoelectron spectroscopy (XPS) and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS), cyclic voltammetry(CV),electrochemical impedance spectra(EIS) and Tafel polarization curve(Taf). The photocatalytic properties of TiO2, TiO2-ZnO, TiO2-Fe2O3 and TiO2-NiO were analyzed by the ability of degradation of methyl orange under visible light irradiation. The experimental results show that the binary heterojunction nanocomposites have been successfully constructed to promote the separation of photogenerated electron-hole pairs and improve the photoelectric performance. The photocatalytic results show that TiO2-NiO exhibits the best photocatalytic performance due to the difference in light utilization efficiency and charge transfer characteristics, which is consistent with the charge transfer resistance of TiO2 > TiO2-ZnO > TiO2-Fe2O3 > TiO2-NiO in EIS results. At the same time, the degradation kinetics of methyl orange (MO) in TiO2-NiO binary heterojunction nanocomposites under visible light irradiation is faster than other samples that can be completed in 160 min. The results show that TiO2-NiO binary heterojunction nanocomposites have broad application prospects in water treatment and wastewater treatment.
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ENERGY & FUELS
·
2018
·
IF 3.024
Dingrui Zhang,Lingyun Hou,Mingyu Gao,Xiaoxiong Zhang
A comprehensive understanding of the thermal cracking behavior of hydrocarbon fuels is important for thermal protection applications and investigations into the combustion of thermally cracked fuels. In the present study, n-dodecane is selected as a surrogate for aviation kerosene and it is subjected to a series of thermal cracking experiments at supercritical pressure. According to variations in chemical heat sink, fuel-conversion rate, and gas-production rate, the thermal cracking of n-dodecane is divided into three regions: primary, secondary, and severe. In the primary cracking region, the fuel-conversion rate is lower than 13%, and the liquid products contain only chain alkanes and alkenes. Owing to the mass fraction of main products being proportional to the fuel-conversion rate, a one-step global reaction kinetics is constructed. The secondary cracking region is characterized by rapidly increasing chemical heat sink, fuel-conversion rates, and gas-production rates with increasing fuel temperature, and the appearance of monocyclic aromatic hydrocarbons (MAHs) and cycloalkenes. A kinetic model containing three reactions is proposed for this region. This also considers the thermal decomposition of chain alkanes and alkenes, which result in the formation of MAHs and cycloalkenes. Severe cracking is observed for fuel-conversion rates above 71% where a rapid increase in the concentration of monocyclic and polycyclic aromatic hydrocarbons (PAHs) occurs. The increasing rate of chemical heat sink slows in this region which is characterized by the formation of MAHs, PAHs, and coke. A three-dimensional numerical model is built for the primary and secondary cracking regions, taking the effects of the flow, heat transfer, and thermal cracking of n-dodecane into consideration. Predicted values for the outlet temperature, fuel-conversion rate, and distribution of the main species in all tested cases agree well with the experimental results, validating the numerical model and kinetics for the primary and secondary thermal cracking of n-dodecane.
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CELLULOSE
·
2019
·Vol. 26
·期 8
·5033-5049
·
IF 3.917
Chen Yong,Ma Yijia,He Qingkun,Han Qiuxia,Zhang Qiang,Chen Qi
Abstract Cotton cellulose was modified with polysiloxane with dual antimicrobial groups of pyridinium and N -chloramine (N-Cl) to endorse enhanced synergistic biocidal ability. A new compound, 4-oxo- N -(pyridin-4-yl)pentanamide (OPPA), that contains precursors of both pyridinium and N -chloramine was synthesized via amidation of 4-oxopentanoic acid and 4-aminopyridine. The molecules of OPPA were connected to cotton cellulose using poly(methylhydrosiloxane) (PMHS) as linker through hydrosilylation reaction between some Si–H groups of PMHS and hydroxyl groups of cellulose and some other Si–H groups and ketone carbonyl groups of OPPA. The OPPA on cellulose was transformed into its biocidal counterpart after quaternization of the pyridine to pyridinium and chlorination of the amide N–H to N -chloramine. The synthetic procedures and modification results were characterized with Fourier-transform infrared spectroscopy, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy. The pyridinium/ N -chloramine polysiloxane layer on cellulose was estimated to be 77 nm by weight and provided powerful and synergistic antibacterial capacities against model species of Escherichia coli and Staphylococcus aureus . The stability of the polysiloxane modifier layer and the rechargeability of lost chlorine were promising under repeated washing, long-term storage, and UV irradiation. The presented pyridinium/ N -chloramine polysiloxane layer showed advantages over many of the current systems containing either cationic salt or N -chloramine due to the synergism. Graphical abstract
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RUSSIAN JOURNAL OF APPLIED CHEMISTRY
·
2019
·Vol. 92
·期 6
·848-856
·
IF 0.508
Lv Jie,Fu Luoping,Zeng Bo,Tang Mingjin,Li Jianbo
In this paper, citric acid was used as carbon source, diethylenetriamine and urotropine were used as precursors, and N-doped carbon dots (cdh-CDs) with luminescent properties were synthesized by microwave method. The structure of the sample was analyzed by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray diffractometry (XRD), ultraviolet spectrophotometer (UV), fluorescence spectroscopy, etc., and it was proved that cdh-CDs with an amorphous structure about 4–10 nm in diameter was synthesized. The corrosion inhibition performance of cdh-CDs in 1 M hydrochloric acid was evaluated by static weight loss and electrochemical method. The results showed that cdh-CDs have a good corrosion inhibition performance at 60°C, the inhibition efficiency can reach 81.2% when the dosage is 600 ppm. Electrochemical results showed that cdh-CDs are mixed inhibitors which mainly inhibit cathodes.
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RSC Advances
·
2018
·Vol. 8
·期 9
·4850-4856
·
IF 2.936
Qian Liu,Danting Li,Zhifeng Zhu,Shimeng Yu,Yan Zhang,Dabin Yu,Yang Jiang
To achieve competitive fluorescence carbon dots (CDs), studies on regulating fluorescence of CDs under controlled, comparable conditions are in great demand. Herein, by changing the functional groups and nitrogenous existence forms in the precursors, three efficient yellow-green emissive N-doped CDs which have the same fluorescence peak wavelength but different photoluminescence quantum yields were realized through a facile hydrothermal method. The as-prepared CDs exhibit not only excited-independent emissions but also similar surface states. The best-performing CDs among the three products exhibits photoluminescence quantum yields of up to 24.4% in water and 53.3% in ethanol, abundant surface functional groups and its high N-doping degree would be the reason for its excellent performances. By washing and reduction processes, the emission evolution of the CDs was studied linking the changes of surface states. The fluorescence can certainly be attributed to the surface of the carbon dots, and the surface states control the photoluminescence features. Serving as a yellow-green colour conversion layer, the best CDs in the three products was used to fabricate a white light-emitting diode. The white light-emitting diode shows an excellent colour rendering index up to 93.3, suggesting broad application prospects of the CDs in lighting and display fields.
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JOURNAL OF PORPHYRINS AND PHTHALOCYANINES
·
2018
·
IF 1.217
Xiaoyu Ren,Haizhou Ren,Yunshan Zhou,Lijuan Zhang,Farooq K. Shehzad,Chao Li
New inorganic-organic transparent composite films of the formula (Zn 2 Al-LDH/ZnTPPS) n were fabricated using exfoliated cationic Zn 2 Al layered double hydroxide (Zn 2 Al-LDH) nanosheets and anionic meso -tertra(4-sulfophenyl) zinc porphyrin (ZnTPPS) through an electrostatic layerbylayer self-assembly method. The resulting composite films were characterized by UV-vis spectroscopy (UV-vis) scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results showed that the films have relatively smooth and orderly surfaces, with the large ring plane of the porphyrin molecules vertically aligned LDH nanosheets and can grow in a nearly linear fashion with increasing the deposition cycles. Z-scan measurements, which were conducted under laser irradiation at a wavelength of 532 nm pulse width of 6 ns, repetition rate of 10 Hz and light intensity at focus E of 10 μ J, revealed that the composite films have notable saturation absorption ( cf. , ZnTPPS in solution shows reverse saturation) and optical nonlinear self-defocusing behavior with the nonlinear optical absorption coefficient β refractive index n 2 , and third-order NLO susceptibility χ (3) of the films increasing with the increase in number of layers of films ( χ (3) value is up to 7.86 × 10 -11 esu when n = 40), implying the NLO responses could be modified by fine tuning the thickness of composite films.
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