JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2020
·
IF 2.369
Dan Zhao,Yun Zhuang,Chunshan Fan,Xihui Zhang,Fang Yang,Yuhuan Chen
The densities of six binary systems containing N,N-dimethylcyclohexylamine (DMCA) and ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, or tert-butanol were reported in this work at temperatures ranging from (288.15 to 318.15) K and atmospheric pressure. According to the experimental density values, molar volume (Vm), thermal expansion coefficient (αp), and excess molar volume (VmE) were calculated. The results showed that VmE values were all negative over the entire composition. The minimum values of the six systems at 298.15 K were located at (−1.097, −1.094, −0.900, −1.033, −1.154, and −1.073) cm3·mol–1 at about xDMCA = 0.4, respectively. All these are dependent on intermolecular interactions and the steric structural effect. Furthermore, VmE variations with composition (xDMCA) as well as temperature were well fitted with the Redlich–Kister-type polynomial equation.
研究领域:
物理化学
·
热力学
✓ 已验证
DOI
高影响因子
Chemical Engineering and Processing-Process Intensification
·
2022
·
IF 4.264
Yuqi Zheng,Yang Jin,Nan Zhang,Dong Wang,Yang Yang,Meng Zhang,Guohui Wang,Shaoxiang Lee,Wenjuan Qu
A Bipolar membrane electrodialysis (BMED) was performed to achieve efficient production of N, N-dimethylglycine (DMG) from dimethylglycine hydrochloride. And the two-compartment cell configuration (BP-A) was used to avoid the amino acid macromolecules migrating through the membrane resulting in membrane fouling. Several experiment parameters including current density, initial dimethylglycine hydrochloride concentration and flow rate were discussed and compared. The results indicated that the optimal operation condition was at the current density of 50 A/m 2 , feed mole concentration of 0.3M and flow rate of 15L/h. Under the optimal condition, the energy consumption was 0.45 kWh/kg, the current efficiency was 65% and the recovery ratio for DMG reached 98% by calculation. In addition, the membrane fouling after experiments was conducted and further analyzed. It was observed that there was no appreciable change on the membrane during the BMED process by the SEM images and FTIR spectra. These results show that the harm of BMED process to membranes could be ignored. BMED method has the advantages of high purity, no by-products, low energy consumption and environmental friendliness. And this study can broaden the application of electrodialysis in the purification and preparation of macromolecular amino acids.
研究领域:
生物工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Yidong Sun,Xingpu Wang,Qiang Fu,Chunxu Pan
Photocatalytic decomposition of water for hydrogen production is considered a promising solution to address the issues of energy crisis and environmental pollution. Herein, a kind of novel hollow flower-like 0D/3D Zn 0.5 Cd 0.5 S/NiCoZn-LDH with an n-n heterojunction is synthesized via precipitation and cation-exchange methods. Photocatalytic experiments reveal that the composite photocatalyst exhibits excellent performance compared with pure Zn 0.5 Cd 0.5 S. In other words, the composite photocatalyst shows enhanced response to visible light, three-fold increased transient photocurrent, and the hydrogen production rate reaching to 1100 μmol/h/g, approximately 7.3 times higher relative to pure Zn 0.5 Cd 0.5 S. The reaction mechanism is also elucidated. Zn 0.5 Cd 0.5 S/NiCoZn-LDH shows a type II n-n heterojunction, which can effectively transfer and separate the photo-generated electrons and holes, and is beneficial for the photocatalytic hydrogen production reaction. The synthesized composite photocatalyst is prepared using a simple method, enabling future large-scale production and applications.
研究领域:
材料科学
·
能源科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2023
·
IF 5.5
Xinyan Yu,Yong Wang,Yutong Dong,Ning Zhao,Lifeng Zhang,Sunting Xuan,Zhengbiao Zhang
N-Methyl peptides, which are widely found in nature, have emerged as an intriguing material in both polymer science and the biomedical field. The inefficient synthesis of N-methyl peptides, however, has greatly impeded the progress toward their structure–property investigation and applications. Here, we report an efficient, moisture-tolerant, primary amine-initiated, and acetic acid-catalyzed ring-opening polymerization of enantiomerically pure N-methyl-α-amino acids N-carboxyanhydrides, yielding well-defined, stereoregular, and structurally diverse N-methyl polypeptides. The concentration of the acetic acid, polarity of solvents, and stiffness of polymer chains were found to be crucial to the rate of the polymerization. The acetic acid was proposed to activate the monomer through hydrogen bonding interaction, promote the release of CO2, and form an acid–base equilibrium with the secondary amine chain end. The obtained N-methyl polypeptides exhibited stable helix structures, revealing chain stiffness, consistent with the high glass transition temperatures (>250 °C) from DSC measurements. Moreover, preliminary studies indicated that N-methyl polypeptides are nontoxic both in vitro and in vivo and are enzymatically stable toward trypsin treatment. Together, this study provides a mild and efficient method for the preparation of N-methyl polypeptides, opening avenues for their further structure–property investigation and potential applications.
研究领域:
高分子科学
·
生物医学领域
·
材料科学
·
有机化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2019
·
IF 2.29
Jian Wang,Yongqin Du,Cunbin Du,Anli Xu,Ganbing Yao,Hongkun Zhao,Xuedong Zhu,Xuhong Guo
For switchable hydrophilicity solvent (SHS) systems ( N,N -Dimethylcyclohexylamine (DMCA), water, and carbon dioxide): the density, viscosity, refractive index and conductivity at (283.15–308.15) K and 0.1 Mpa, were measured. The apparent molar volumes were determined as a function of composition at each temperature from experimental data. Based on Masson’s equation limiting apparent molar volumes and Masson’s coefficient S V describing the character of interactions were calculated. The relative viscosity values were adjusted to obtain the viscosity B coefficients and dB/dT values. It has been observed that there exist strong solute-solvent and solute-solute interactions in these systems, and DMCAH-bicarbonate salt acts as structure-maker in aqueous solvent.
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2021
·
IF 2.694
Xiaoyu Wang,Jiale Wang,Lijun Ji,Bin Wu,Kui Chen,Yanyang Wu
Wastewater containing DMF (N,N-dimethylformamide) and salt is generated in production of many chemicals and medicines. The composition of phase equilibrium should be known primarily for the recovery of DMF from salt-containing wastewater by solvent extraction. In this study, liquid–liquid equilibrium (LLE) and solubility data of water + DMF + chloroform in the presence of NaCl with various concentrations of 0, 2.5, 5.0, 7.5, 10.0, and 13.3 wt % and Na2SO4 with concentrations of 1.5 and 2.5 wt % were determined at T = 298.2 K and atmospheric pressure. Besides, the salt effect on the LLE data was investigated. Compared with the salt-free system, the salt led to an enhancement in the maximum DMF distribution coefficient by 13.4–102.6% for 2.5–13.3 wt % NaCl and 16.2–31.7% for 1.5–2.5 wt % Na2SO4, respectively. Since the distribution coefficient of water increased concurrently, the separation factor barely changed and the two-phase region expanded outward slightly. At the same salt mass fraction, the order of salting-out effect strength on extraction was Na2SO4 > NaCl, which was in good agreement with the Hofmeister series. The reliability of the experimental values was verified through the Eisen–Joffe equation. The NRTL thermodynamic model was applied to correlate the experimental data with a root-mean-square deviation less than 0.0062. The coherent consistency of the model parameters for the salt-free system was checked by topological analysis based on the Gibbs tangent plane test.
研究领域:
化学工程
·
环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2018
·
IF 2.732
Xuelei Pang,Tao Yu,Fengjuan Shen,Xudong Yu,Yajuan Li
Two novel luminescent lanthanide acylamide derivatives covalently grafted to xerogels (donated as Ln-pp-xerogel, Ln = Eu, Tb) were designed and synthesized in situ via a sol-gel process. The properties of these xerogels were examined by Fourier-transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, thermo-gravimetric analysis, and photoluminescence spectroscopy. The results suggest that the lanthanide derivatives were successfully covalently bonded to the inorganic silica host. The obtained xerogel materials exhibit good thermal stabilities and possess the excellent characteristic luminescence of the corresponding lanthanide ions, which is ascribed to the energy transfer from the organic ligands to the lanthanide ions via an antenna effect. Both the xerogels in acetonitrile solution were used to selective recognition of F − ions and small organic molecule N, N-dimethylformamide by measuring the change in the signal output, which were studied by fluorescence spectroscopy in detail. The sensing mechanisms were studied by the titration of 1 H NMR spectroscopy.
研究领域:
化学
·
材料科学
✓ 已验证
DOI
高影响因子
Frontiers in Microbiology
·
2023
·
IF 5.2
Liu Quanzhen,Wei Guoguang,Yang Pengfan,Wang Chengyong,Chen Kequan,Ouyang Pingkai,Zhang Alei
N-acetylneuraminic acid (Neu5Ac) possesses the ability to promote mental health and enhance immunity and is widely used in both medicine and food fields as a supplement. Enzymatic production of Neu5Ac using N-acetyl-D-glucosamine (GlcNAc) as substrate was significant. However, the high-cost GlcNAc limited its development. In this study, an in vitro multi-enzyme catalysis was built to produce Neu5Ac using affordable chitin as substrate. Firstly, exochitinase SmChiA from Serratia proteamaculans and N-acetylglucosaminosidase CmNAGase from Chitinolyticbacter meiyuanensis SYBC-H1 were screened and combined to produce GlcNAc, effectively. Then, the chitinase was cascaded with N-acetylglucosamine-2-epimerase (AGE) and N-neuraminic acid aldolase (NanA) to produce Neu5Ac; the optimal conditions of the multi-enzyme catalysis system were 37°C and pH 8.5, the ratio of AGE to NanA (1:4) and addition of pyruvate (70 mM), respectively. Finally, 9.2 g/L Neu5Ac could be obtained from 20 g/L chitin within 24 h along with two supplementations with pyruvate. This work will lay a good foundation for the production of Neu5Ac from cheap chitin resources.
研究领域:
生物技术
·
酶学
·
食品科学
·
医学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
·
2018
·Vol. 29
·期 11
·2724-2734
·
IF 2.137
Wei Liu,Xiaolian Zhu,Xinlin Yang,Ke Li,Zupeng Yang
An effective polymerization system was developed for the synthesis of highly cross-linked hydrophilic monodispersed microspheres with both the micropores and mesopores inside. A series of poly( N , N ′-methylenebisacrylamide) (PMBA) microspheres with the diameters ranging from 100 to 300 nm were synthesized by distillation precipitation polymerization with N , N -dimethylacetamide (DMAC) as the porogen, acetonitrile as the solvent, and MBA as the cross-linker and monomer. The particle size, morphology, and porosity varied according to the variation of the DMAC content. The porosity was determined by physical adsorption of nitrogen, and reached the maximum at 7.5 vol% of DMAC with the specific surface area at 135.8 m 2 g −1 and the total pore volume at 0.43 cm 3 g −1 . The porous and hydrophilic microspheres showed excellent swelling property in water and adsorption property for the Cd(II) in aqueous solution. Meanwhile, carboxylic groups were incorporated into the porous microspheres to achieve porous poly( N , N ′-methylenebisacrylamide- co -acrylic acid) (P (MBA- co -AA)-P), which exhibited obvious synergies of the pores and functional groups on the adsorption and provided a perspective application of the Cd(II) removal.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2024
·
IF 3.7
Dandan Jiang,Yingzhen Zhang,Xin Qiao,Jun Xiao,Kunming Liu,Juanhua Li,Jinbiao Liu
An iron-catalyzed selective N═S coupling of N-methoxy amides and sulfoxides has been developed and was found to be a highly efficient method for the synthesis of N-acyl sulfoximines. Electron-donating as well as electron-withdrawing groups on the phenyl ring are tolerated, and even sensitive substituents are compatible. The current catalytic transformation was conducted under an air atmosphere and can be easily scaled up to a gram scale with a catalyst loading of only 1 mol %. In this case, both coupling partners are used in their native forms, thus obviating prior functionalization and activation.
研究领域:
有机化学
·
合成化学
✓ 已验证
DOI
PubMed
高影响因子
DALTON TRANSACTIONS
·
2018
·Vol. 47
·期 33
·11530-11538
·
IF 4.099
Xuelei Pang,Li Li,Yi Wei,Xudong Yu,Yajuan Li
Two novel luminescent organic–inorganic hybrid materials, Ln(L-SBA15)3phen (Ln = Eu, Tb), were designed and synthesized. The organic ligand phenylurea was modified by the silane coupling agent 3-(triethoxysilyl)propyl isocyanate (TESPIC) to form a precursor (L), which was covalently bonded onto a mesoporous SBA-15 backbone to form mesoporous L-SBA15 through co-hydrolysis and co-condensation reactions. 1,10-Phenanthroline monohydrate (phen) was selected as the second ligand to improve the luminescence of the final products, and the two mesoporous hybrid materials Ln(L-SBA15)3phen were obtained after the coordination reaction between the organic ligands (phen and L-SBA15) and Ln(III) ions. Both the mesoporous hybrid materials were examined by Fourier transform infrared spectroscopy, transmission electron microscopy, small-angle X-ray diffraction, N2 adsorption–desorption curves, and photoluminescence spectroscopy. The results show that both the hybrid materials showed highly ordered mesoporous structures, high surface areas, and excellent photophysical properties (long luminescence lifetimes and high quantum efficiencies). Furthermore, the fluorescence sensing properties of the materials were investigated systematically, and the hybrid materials were revealed to be promising examples of dual functional materials with good ability to sense fluoride ions and a small organic molecule N,N-dimethylformamide.
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2019
·
IF 2.29
Dan Zhao,Yun Zhuang,Chunshan Fan,Fang Yang,Yuhuan Chen,Xihui Zhang
Surface tension ( γ ) for five binary mixtures containing N, N-dimethylcyclohexylamine (DMCA) and alcohol, ethanol, n-propanol, iso -propanol, n-butanol or iso -butanol were measured over the whole range of composition at 0.1 MPa and different temperatures ranging from (288.15 to 308.15) K. From the experimental data, the surface tension deviations ( δγ ) for the binary mixtures were calculated. The δγ values are positive for all the studied systems and increase with the decreasing of alky chain length of alcohol. For the mixture containing the branched alkyl alcohol, the increase is significant compared with the equivalent molecules with straight chains. According to temperature dependence of surface tension, the thermodynamic parameters, surface enthalpy ( H γ ) and surface entropy ( S γ ) were also estimated and further discussed.
研究领域:
物理化学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）