JOURNAL OF CARBOHYDRATE CHEMISTRY
·
2020
·
IF 0.855
Lei Wang,Xiangxiang Qin,Xueyan Miao,Haishan Chen,Yuheng Zhou,Aihua Cai
Carboxymethyl xylan (CMX) was synthesized and characterized. A method based on quantitative 13C NMR was developed to obtain detailed structural information. The total degree of substitution (DS), partial DS at 2- and 3-O-positions, and the quantitation of each unit in CMX could be acquired simultaneously by this method without decomposing the polymer backbone, thus avoiding errors caused by polymer hydrolysis with traditional methods using HPLC and 1H NMR spectrometry. Moreover, different from methods of direct detection of carboxyl groups, such as acidometric and potentiometric titrations, this method was not affected by probable impurity introduced during carboxymethylation.
研究领域:
植物化学
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材料科学
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分析化学
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DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
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2017
·
IF 2.726
Shufeng Shen,Yue Zhao,Yangyang Bian,Yong Wang,Hui Guo,Hui Li
The solubility of CO 2 in aqueous potassium lysinate (LysK) solutions was measured in a stirred reactor at temperatures from 298 to 353 K, for 9.0, 17.4, 25.3, 33.1 and 41.2 mass% LysK and CO 2 partial pressures up to 110 kPa. The vapor-liquid equilibrium (VLE) data were interpreted using the modified Kent-Eisenberg model. The apparent equilibrium constants of carbamate hydrolysis and amino acid deprotonation were correlated as a function of temperature, CO 2 loading (expressed as mole CO 2 per mole LysK) and LysK concentration to fit the experimental solubility data. The proposed model satisfactorily predicted the VLE data for the H 2 O-LysK-CO 2 system, especially at moderate to high CO 2 loading, with an average absolute deviation within 3.2%. Liquid species in the CO 2 -loaded LysK solutions were also qualitatively characterized by 13 C NMR experiments.
研究领域:
化学工程
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环境科学
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Yanan Yu,Yao Shen,Ke Wang,Jingkai Zhao,Jiexu Ye,Lidong Wang,Shihan Zhang
Amine-based technology is promising for CO 2 capture from the flue gas . However, it encounters high energy penalty and thus hampers its industrial application. Currently, the catalytic solvent regeneration is developing to lower down regeneration temperature, accelerate regeneration rate, and cut down energy consumption for monoethanolamine (MEA)-based process. However, the information on catalytic regeneration of biphasic solvent is seldom available. This work develops a facile synthesized robust catalyst, α-Fe 2 O 3, to promote the biphasic solvent regeneration such as triethylenetetramine (TETA) and 2-(diethylamino) ethanol (DEEA) blend. Experimental results revealed that, with the aid of α-Fe 2 O 3 , the efficient regeneration of TETA-DEEA occurred at 94 °C, which is far below the conventional MEA-based process (110–120 °C). The corresponding CO 2 stripping rate increased by 2.4 times compared with uncatalytic scenario. Furthermore, the relative energy consumption was furtherly decreased by 41.6%. Different from MEA regeneration, the biphasic solvent regeneration with α-Fe 2 O 3 depended on the enhancement of water molecules proton donation rather than the abundant Brønsted acid and Lewis acid of the catalyst. Based on DFT calculation and 13 C NMR spectra analysis, the water molecules on α-Fe 2 O 3 surface and the protonated DEEA were parallel served as proton donors for carbamate decomposition. Consequently, a novel proton transfer mechanism was proposed for the biphasic solvent TETA-DEEA regeneration. The water molecules adsorbed on α-Fe 2 O 3 surface generated oxyhydrogen groups and thus donate protons for the carbamate decomposition. This work proposes a novel proton transfer mechanism for solvent regeneration and advances its industrial application with a low energy penalty.
研究领域:
环境科学
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化学工程
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催化
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能源技术
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DOI
高影响因子
APPLIED ENERGY
·
2018
·
IF 7.9
Fei Liu,Mengxiang Fang,Wenfeng Dong,Tao Wang,Zhixiang Xia,Qinhui Wang,Zhongyang Luo
Using biphasic solvents for carbon dioxide (CO 2 ) capture is regarded as a promising technology to drastically reduce the regeneration energy. However, this technology hasn’t been put into commercial application due to lack of the biphasic solvents with high stabilities and low costs. To overcome this challenge, we developed a novel type of biphasic solvent based on alkanolamine-alkanolamine blends, i.e., aqueous blends of 2-(diethylamino)-ethanol (DEEA, 50 wt%) and monoethanolamine (MEA, 25 wt%) or 2-((2-aminoethyl) amino) ethanol (AEEA, 25 wt%). The aqueous DEEA-AEEA solvent demonstrated a cyclic capacity as high as 0.64 mol CO 2 /mol which is significantly higher than those of 30 wt% MEA and other reported biphasic solvents. In addition, a phase split time as short as a few minutes is obtained. The phase split dynamics were analyzed to investigate the effects of CO 2 loading, temperature, gas flow rate and height-to-diameter ratio. Quantitative 13 C NMR analysis was then performed to reveal the reaction and phase split mechanism of CO 2 absorption in the DEEA-AEEA solvent. It indicated that the reaction of AEEA with CO 2 dominated at the beginning of CO 2 absorption and the products are formed as carbamates. Then, DEEA began reacting with CO 2 to yield bicarbonate and carbonate. The phase split mechanism indicated that the reaction products of carbamates and HCO 3 − /CO 3 2− migrated to the lower phase while DEEA and unreacted AEEA migrated to the upper phase. Finally, the cyclic tests were repeated and the energy consumption was evaluated. The regeneration energy of the biphasic solvent, without process optimizations, is 2.58 GJ/tCO 2 , which is 32% lower than that of the traditional 30 wt% MEA solvent.
研究领域:
化学工程
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环境科学
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能源技术
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产品关联
DOI
高影响因子
BIOPOLYMERS
·
2013
·Vol. 101
·期 3
·210-215
·
IF 2.879
Xin Liu,Tong Chen,Yan Hu,Kexin Li,Liushui Yan
Sulfated derivatives of polysaccharide from Momordica charantia L. (MCPS) with different degree of sulfation (DS) were synthesized by chlorosulfonic acid method with ionic liquids as solvent. Fourier transform infrared spectra and 13 C nuclear magnetic resonance spectra indicated that C-6 substitution was predominant in MCPS compared with the C-2 position. Compared with the native polysaccharide from Momordica charantia L. (MCP), MCPS exhibited more excellent antioxidant activities in vitro, which indicated that sulfated modification could enhance antioxidant activities of MCP. Furthermore, high DS and moderate molecular weight could improve the antioxidant activities of polysaccharide. © 2013 Wiley Periodicals, Inc. Biopolymers 101: 210–215, 2014.
研究领域:
生物大分子化学
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药学
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分析化学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2020
·
IF 9.038
Can Cheng,Jianjun Li,Jinyan Cao,Jiaxiu Guo,Wanglai Cen
The absorption properties of N-(2-hydroxyethyl) morpholine (HEM), morpholine (MP) and N-(2-aminoethyl) morpholine (AEM) for SO 2 were studied using sulfolane (SUL) as solvent in this work. Among these solvent combinations, HEM/SUL shows the best cyclic absorption performance, and the capacity of HEM-SUL-40 (40 wt% of HEM and 60 wt% of SUL) to absorb 8580 mg/m 3 SO 2 (the remainder is N 2 ) is 192.18 mg/g at 293.15 K. The absorption capacity of the second cycle is 97.5% of the first absorption cycle, which is higher than 70% of the Cansolv amine solution in a commercial application with similar experimental conditions. However, MP/SUL is difficult to desorb at high temperature, and the absorption capacity of AEM/SUL is much lower than HEM/SUL and MP/SUL. According to the FTIR , 1 H NMR and 13 C NMR, all three cyclic amines have charge transfer effects with SO 2 . The structure of HEM/SUL can be recovered after heating, but MP cannot be recovered. Δ r G m ° in the reaction against HEM with SO 2 increases significantly with increasing temperature. The Δ r G m ° of HEM-SO 2 and MP-SO 2 at 353.15 K is −12.56 kJ/mol and −16.29 kJ/mol, respectively, which further explains the easy desorption of HEM-SO 2 and the difficult desorption of MP-SO 2 at high temperature.
研究领域:
化学工程
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环境科学
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物理化学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF PHARMACEUTICAL SCIENCES
·
2024
·
IF 3.7
Jiawei Han,Yang Yang,Yunjuan Hou,Mengyuan Tang,Yunran Zhang,Yijun Zhu,Xiaoqian Liu,Jue Wang,Yuan Gao
Intermolecular interactions between drug and co-former are crucial in the formation, release and physical stability of co-amorphous system. However, the interactions remain difficult to investigate with only experimental tools. In this study, intermolecular interactions of co-amorphous curcumin-piperine (i.e., CUR-PIP CM) during formation, dissolution and storage were explored by integrating experimental and modeling techniques. The formed CUR-PIP CM exhibited the strong hydrogen bond interaction between the phenolic OH group of CUR and the C O group of PIP as confirmed by FTIR, ss 13 C NMR and molecular dynamics (MD) simulation. In comparison to crystalline CUR, crystalline PIP and their physical mixture, CUR-PIP CM performed significantly increased dissolution accompanied by the synchronized release of CUR and PIP, which arose from the greater interaction energy of H 2 O-CUR molecules and H 2 O-PIP molecules than CUR-PIP molecules, breaking the hydrogen bond between CUR and PIP molecules, and then causing a pair-wise solvation of CUR-PIP CM at the molecular level. Furthermore, the stronger intermolecular interaction between CUR and PIP was revealed by higher binding energy of CUR-PIP molecules, which contributed to the excellent physical stability of CUR-PIP CM over amorphous CUR or PIP. The study provides a unique insight into the formation, release and stability of co-amorphous system from MD perspective. Meanwhile, this integrated technique can be used as a practical methodology for the future design of co-amorphous formulations.
研究领域:
药学
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材料科学
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计算化学
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产品关联
DOI
PubMed
高影响因子
AAPS PHARMSCITECH
·
2021
·Vol. 22
·期 5
·1-14
·
IF 3.246
Luo Zheng,Liu Chao,Quan Peng,Zhang Yimeng,Fang Liang
Chemical penetration enhancers (CPEs) are commonly added into transdermal patches to impart improved skin permeation of drug. However, significant unexplained variability in drug release kinetics in transdermal patches is possible as a result of the addition of CPEs; investigations into the underlying mechanisms are still limited. In the present study, a diverse set of CPEs was employed to draw broad conclusions. Solubility parameters of CPEs and acrylate pressure-sensitive adhesive were calculated by molecular dynamics simulation and Fedors group contribution method to evaluate drug-adhesive miscibility. CPE-adhesive interaction was characterized by FT-IR study, 13 C NMR spectroscopy, and molecular docking simulation. Results showed that release enhancement ratio ( ER R ) of CPEs for zolmitriptan was rank ordered as isopropyl myristate > azone > Plurol Oleique ® CC497 > Span ® 80 > N -methylpyrrolidone > Transcutol ® P. It was found that solubility parameter difference (Δ δ ) between CPE and adhesive was negatively related with ER R . It was proved that hydrogen bonding between CPE and adhesive would increase drug release rate, but only if the CPE showed good miscibility with adhesive. CPE like isopropyl myristate, which had good miscibility with adhesive, could decrease drug-adhesive interaction leading to the release of drug from adhesive.
研究领域:
药剂学
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药学化学
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生物物理学
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材料科学
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DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2024
·
IF 7.7
Lihua Chen,Fang Yang,Qixing Jiang,Pei Gao,Wenshui Xia,Dongxing Yu
Starch is a common ingredient to improve gel property of freshwater fish surimi, but the function of natural starch to mask fishy odor compounds in surimi products has not been investigated systematacially. Therefore, this study aimed to determine which natural starch could effectively mask fishy odor compounds and clarify their interaction by GC–MS, FT-IR spectroscopy, raman spectroscopy, X-ray diffraction, scanning electron microscopy and 13 C nuclear magnetic resonance. The results showed that when the concentration, crystal type, amylose content, and dispersion degree of starch was 1 %, type C, 48 % ( w / v ), and 200 mesh with 0.88 span, the starch had the strongest masking effect on typical fishy odor compounds, namely hexanal, 1-Octen-3-ol, (E,E)-2,4-Heptadienal and (E)-2-Octenal. It indicated that complexation and hydrogen bonding both occurred between the fishy odor compounds and starch.
研究领域:
食品科学
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分析化学
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材料科学
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Yuhang He,Zeen Zhang,Hua Ke,Yangcheng Lu
Ethylene content in ethylene–vinyl acetate copolymers (EVA) is a key factor that determines its further usage. While conventional batch reactor for EVA synthesis faces the problem of heterogeneous reaction environment and temperature control. A microflow system was designed to avoid these problems and facilitate the synthesis of EVA with controlled ethylene content. Continuous flow synthesis of EVA by solution free radical copolymerization was realized homogeneously based on this microflow system. 13 C NMR spectra indicate that EVA obtained in microflow system has less ethylene concentrated sequence than EVA obtained in batch reactor. By operating the microflow system in a stop-flow method, we developed a simple kinetic model of copolymerization and measured the reactivity ratios of ethylene and vinyl acetate copolymerization in tert -butyl alcohol and dimethyl carbonate. The microflow system is demonstrated to be a powerful tool in kinetic and mechanism study and engineering application of copolymerization processes involving monomers which are gas phase under conventional condition.
研究领域:
化学工程
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高分子科学
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材料科学
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DOI
高影响因子
JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
·
2018
·
IF 1.454
Lujiao Shi,Yi Wei,Nan Luo,Tianwei Tan,Hui Cao
In the present study, cationic xanthan gum (CXG) was synthesized to enhance the rheological property of xanthan gum (XG) by attaching quaternary amine groups to the backbone of XG. The efficacy of the substitution was confirmed by FT-IR spectra and 13C NMR. The surface morphology was changed considerably as demonstrated by SEM. The examined rheological properties of XG and CXG include steady-state and dynamic rheological properties. The results show that quaternary amine groups are successfully grafted onto the XG molecule. Apparent viscosity, storage modulus, and loss modulus of CXG solutions are greater than those of XG solutions under the same conditions. It is moreover found that apparent viscosity and viscoelasticity increase with the degree of substitution. The data indicate that the modified XG has much better heat resistance.
研究领域:
化学工程
·
材料科学
·
流变学
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产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2024
·
IF 5.3
Sen Qin,Shanshan Dai,Wei Fan,Mei Li,Zou He,Jie Qi,Yang Yang,Huan Yan
To achieve excellent absorptive loading and low viscosity, a novel amino-functionalized ionic liquid [G1.0 PAMAM] [2-MI] combined with water for CO 2 capture is proposed in this work. The concentration of [G1.0 PAMAM] [2-MI], absorption temperature, and aeration rate were optimized by using Response Surface Methodology based on Box-Behnken design, and the model predictions were in good agreement with the experimental data. The results illustrated that the absorption loading of 42.71 wt% [G1.0 PAMAM] [2-MI]/H 2 O was 6.81 mol CO 2 /mol ILs (38.5°C, 100 mL/min), which was much higher than that of MEA /H 2 O, and the regeneration efficiency was maintained at 89.5 % after the eighth regeneration cycle. With the combined effect of 2-MI and water, the viscosities of the solution before and after absorption at 40°C were 35.3 and 53.8 mPa·s, respectively, which were significantly lower than those of the majority of ionic liquid absorbents. The reaction mechanism of [G1.0 PAMAM] [2-MI] with CO 2 was demonstrated by 13 C NMR to be a synergistic combination of a zwitterionic mechanism and a base-catalyzed hydration mechanism to produce carbamate and carbonate/bicarbonate (CO 3 2– /HCO 3 – ).
研究领域:
化学工程
·
环境科学
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材料科学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）