JOURNAL OF CHEMICAL THERMODYNAMICS
·
2018
·
IF 2.631
Ting Zheng,Jiaojiao Fang,Qinglong Xie,Zhenyu Wu,Meizhen Lu,Fan Xia,Dongshun Deng,Yong Nie,Jianbing Ji
Fatty acid 2-ethylhexyl esters are used for the eco-friendly production of biolubricant. There are several reports on their synthesis, but thermodynamics and transport data of these compounds are lacking. Herein, density and viscosity of palmitic acid 2-ethylhexyl ester, stearic acid 2-ethylhexyl ester and soya oil 2-ethylhexyl esters in the temperature range of T = (298.18–368.15) K at atmospheric pressure were measured and the vapor pressure in the temperature range of T = (476.95–500.85, 477.05–498.05, 477.75–500.05) K was determined. The obtained experimental data were correlated using temperature-dependence correlation equations, and the correlation coefficients of all the equations were over 0.999. In order to examine the reliability of the data, the GCVOL group method was used to evaluate densities for these fatty acid 2-ethylhexyl esters with the maximum relative deviation of −1.34%. The experimental viscosity data of synthesized 2-ethylhexyl esters were compared with those of lauric acid 2-ethylhexyl ester, palmitic acid n-octyl ester and oleic acid 2-ethylhexyl ester from previous studies. In addition, the molar enthalpy of vaporization at the mean temperature of the experimental range was calculated for the first time using the Clausius-Clapeyron equation.
研究领域:
物理化学
·
热力学
✓ 已验证
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Chenyang Zhu,Ziwen Zhang,Sa Xue,Kun Hou,Hui Liu,Xiangyang Liu,Maogang He
The mixtures of fatty acid ester + alcohol are promising substitution fuels in engines. Due to their strong self- and cross-hydrogen bonds, the properties of these kinds of mixtures may show different characteristics from the fossil fuels composed of non-associating substances. In this work, the association effects on density and viscosity of fatty acid ester + alcohol are investigated from both experimental and theoretical aspects. The ethyl laurate + ethanol mixtures with 9 M fraction compositions are chosen, and the two properties are measured using a capillary viscometer system at temperatures from 313 K to 343 K and pressures up to 15 MPa. The positive excess volume and viscosity deviation of the mixtures are obtained, and the former is negligible compared to the experimental uncertainty. The Cubic-Plus-Association equation of state (CPA EoS) and the friction theory model are used to model the mixtures of ethyl laurate + ethanol. The relations of their self- and cross-associations to density, viscosity, and two excess properties (excess volume and viscosity deviation) are summarized. Different saturated fatty acid ester + 1-alcohol mixtures are also modeled with the CPA EoS. The variation characteristics of their viscosity deviations are analyzed and explained by their different association strength and the mole number of associated molecules.
研究领域:
化学工程
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2019
·
IF 2.298
Dan Li,Juan Wang,Yanan Gao,Xinyu Zhan,Mengyun Li,Yuxiang Wang
The density, viscosity, and refractive index data of binary mixtures for the main components of biodiesel (ethyl caprylate, ethyl caprate, and ethyl myristate) with ethylcyclohexane in the whole range of composition were measured at T = (293.15–323.15) K. The excess molar volumes (VmE) and viscosity deviations (Δη) were calculated based on the measured data and correlated with the Redlich–Kister equation. The standard deviations, average percentage deviation, and regression coefficients are given. Positive values of VmE and negative values of Δη were observed in all the tested binary systems over the entire range of composition.
研究领域:
化学工程
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
Green Processing and Synthesis
·
2022
·Vol. 11
·期 1
·184-194
·
IF 3.97
Qiuyun Zhang,Binbin Yang,Yuanyuan Tian,Xianju Yang,Rongfei Yu,Jialu Wang,Taoli Deng,Yutao Zhang
In the present study, a facile solvothermal method was used for the synthesis of silicotungstic acid (HSiW) immobilized on Ce-based metal organic framework (Ce-BDC) and embedded in Zr-based metal-organic framework (UiO-66(Zr)) composite catalyst, namely, Ce-BDC@HSiW@UiO-66 for the production of biodiesel through green fatty acid esterification. The obtained hybrids were characterized by various characterization technologies, including Fourier transform infrared, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N 2 physisorption, X-ray photoelectron spectroscopy, and temperature-programmed desorption of NH 3 (NH 3 -TPD) analysis. The characterization analyses showed that the hybrids have been successfully synthesized. Also, the volume and pore size of UiO-66(Zr) were changed by introducing HSiW@Ce-BDC, and the resulting Ce-BDC@HSiW@UiO-66 possessed the mesoporous structure and relatively high surface area. Simultaneously, the NH 3 -TPD analysis of Ce-BDC@HSiW@UiO-66 reveals that the acid strength was increased in comparison with HSiW@Ce-BDC. In addition, the composite Ce-BDC@HSiW@UiO-66 demonstrated high catalytic activity, and the oleic acid esterification gave 81.5% conversion at optimum conditions of 0.2 g catalysts, 1:30 oleic acid to methanol molar ratio at 130°C for 4 h. More interestingly, after six recycling cycles, the reduction in the conversion rate was only 4.6%, indicating that Ce-BDC@HSiW@UiO-66 has excellent reusability. Our study provides an effective approach to synthesize multifunctional hybrids for green biofuel production.
研究领域:
化学工程
·
催化材料
·
可再生资源
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2019
·
IF 4.784
Qiong Xiao,Guo Chen,Anfeng Xiao
Two types of fatty acid derivatives were used to synthesize agarose fatty acid esters in a heterogeneous medium. Agarose esters with low degree of substitution were synthesized with succinic anhydride, octenyl succinic anhydride, dodecyl succinic anhydride as esterifying agents. Agarose esters with high degree of substitution were synthesized with lauroyl chloride, palmitoyl chloride, and stearoyl chloride as esterifying agents. Scanning electron microscopy revealed that agarose anhydride modification mostly occurred at the surface of the particles, whereas chloride modification occurred at both the surface and interior of the particles. Fourier transform infrared spectroscopy and nuclear magnetic resonance analyses indicated that hydrophobic groups were successfully introduced in agarose, and the hydroxyl group in the C-2 of D-galactose was the preferred location for esterification . The results also showed that agarose esters with long-chain fatty acids and high substitution degree showed higher emulsifying ability and low interfacial tension property than derivatives with short-chain fatty acids and low substitution degree. Compared with commonly used food emulsifiers, such as Tween, sucrose fatty acid ester, and glycerin monostearate, agarose esters were slightly deficient in emulsifying ability but presented high emulsion stability in oil-in-water emulsion.
研究领域:
食品科学
·
材料化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Polymers
·
2019
·Vol. 11
·期 6
·1030
·
IF 3.164
Cai Wang,Han Wang,Faxing Zou,Shaojun Chen,Yiping Wang
In this study, we report the synthesis of a novel bio-based material from polyhydroxyalkanoate (PHA) with good shape-memory effect (SME) and rapid recovery. In this PHA-based polyurethane (PHP), telechelic-hydroxylated polyhydroxyalkanoate (PHA-diols) and polyethylene glycol (PEG) were used as soft segments, providing thermo-responsive domains and water-responsive regions, respectively. Thus, PHP possesses good thermal-responsive SME, such as high shape fixing (>99%) and shape recovery ratio (>90%). Upon immersing in water, the storage modulus of PHP decreased considerably owing to disruption of hydrogen bonds in the PHP matrix. Their water-responsive SME is also suitable for rapid shape recovery (less than 10 s). Furthermore, these outstanding properties can trigger shape-morphing, enabling self-folding and self-expansion of shapes into three-dimensional (3D) scaffolds for potential biomedical applications.Keywords:polyhydroxyalkanoate;polyurethane;water-thermal responsive;shape-memory;scaffolds
研究领域:
生物材料
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组织工程
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF DRUG DELIVERY SCIENCE AND TECHNOLOGY
·
2021
·
IF 3.981
Lan Mo,Guang-lei Zhao,Xiao-feng Li,Xing-long Xiao,Ning He,Hai-xia Xu,Yi-gang Yu
Design and synthesis of prodrugs is an effective strategy to develop new drugs. Puerarin is well-known for its pharmacological properties in the treatment of many cardiovascular and cerebrovascular related diseases. To cope with its poor liposolubility that limited practical applications, we successfully developed a new type of clean and efficient esterification medium for acylation modification of puerarin and studied the relative oral absorption, including pharmacokinetics , tissue distribution and metabolite after oral taking of puerarin acid esters in comparison with free puerarin in rats. In the 1-Ethyl-3-Methylimidazoliumacetate, puerarin had the good solubility, and the reaction showed great initial rate (46.71 mmol/(L*h)) and substrate conversion (63.91%). The results of oral absorption showed that the administration of long-chain fatty acid esters of puerarin, puerarin hexanoate and puerarin myristate , resulted in significantly higher levels of puerarin in the plasma and tissues, especially in the heart, cerebral cortex, hippocampus and corpus striatum. Overall, these findings collectively supported that puerarin acid esters administration led to greater circulating concentration of puerarin and had a reduced excretion rate, providing significant advantages and theoretical basis for their application in functional foods and pharmaceutical industries.
研究领域:
药物化学
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药理学
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生物医学工程
✓ 已验证
DOI
高影响因子
EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY
·
2015
·Vol. 117
·期 7
·918-925
·
IF 1.812
Ziliang Song,Yong Wang,Guoqiang Li,Wei Tan,Shengwen Yao
A new approach for determination of glycidyl fatty acid esters (GDEs) based on 1 H nuclear magnetic resonance ( 1 H NMR) spectroscopy was developed. The 1 H NMR spectra of the GDE standards were prepared and characterized. The quantification formula was then deduced from the characteristic signals of two epoxy methylene (CH 2 ) protons at chemical shifts 2.56 and 2.76 ppm. Tests on repeatability, reproducibility, and recovery were conducted and proved the reliability of the quantification method. This method was extended to GDEs mixed with oil matrices composed of different acylglycerols (GREs). The weighted average factor f w is introduced to calculate the fatty acid composition based on the stoichiometric proportion of the lipid component and its esterification degree. With the fatty acid composition determined, the molar percentage obtained from 1 H NMR can be converted to the weight percentage. This method is an analytical model for the determination of GDEs, with advantages such as easy operation and high accuracy. Practical applications: Heat treatment of edible oils in the refinery process can generate GDEs, a group of contaminants having potential risks to liberate a carcinogenic compound called glycidol during digestion of oil in the human body. It has become an important issue for the oil industry to develop an effective method for the determination of GDEs. The proposed 1 H NMR spectroscopic method is able to characterize and quantify GDEs in an accurate, rapid, and noninvasive way. With these advantages, the analytical results also provide quantitative criteria for subsequent concentration and mitigation of GDEs in refined edible oils. A novel 1 H NMR spectroscopic method was developed to determine glycidyl fatty acid esters (GDEs), a processing contaminant in refined edible oil.
研究领域:
食品科学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2022
·
IF 7.693
Jikun Ma,Hui Liu,Dawei Sun,Jianfeng Wang,Suping Cui
In this study, novel microencapsulated phase change materials (PU-UF MPCMs) with methyl palmitate and methyl stearate as core and double-layered shell structure were designed for building energy conservations. Their composition, microstructure and thermal performances were determined by techniques including optical microscope (OM), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Effects of PU-UF MPCMs on the thermal performance of cementitious composites were also investigated. Results show that PU-UF MPCMs with spherical shape and double-layered shell structure were successfully prepared. DSC results show that the latent heat of PU-UF MPCMs is 137.6 J/g and the melt temperature of cores in PU-UF MPCMs is 24.2 °C. 5%-15% PU-UF MPCMs addition increases the thermal storage capacity of cement pastes through a phase transition process, among which 15% PU-UF MPCMs leads to the highest thermal storage capacity. Those results suggest that PU-UF MPCMs exhibit the potential for enhancing energy savings and thermal comfort of buildings.
研究领域:
材料科学
·
建筑工程
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Green Energy
·
2024
·
IF 3.1
Jiaping Zhao,Xincheng Cao,Peng Liu,Feng Long,Shiyu Wu,Junming Xu,Jianchun Jiang
The hydrogenation of bio-based oil into biodiesel is a key strategy in reducing reliance on fossil fuels. However, efficient catalysts are needed to enable low-temperature hydrogenation reactions due to the current high-temperature requirement for bio-based oil hydrogenation. Here, bimetallic catalysts Rex-Ru/C for low-temperature hydrogenation of bio-based oils were prepared. The presence of Re oxides (ReOx) in the catalyst enhances the abundance of weak and medium acid sites, thereby facilitating the adsorption of H2. The DFT calculation shows the introduction of Re also improved the adsorption capacity of the catalyst for fatty acid methyl ester and H2. The Re0.25-Ru/C catalyst exhibits superior conversion, selectivity, and recyclability at low temperatures compared to the previously reported catalysts, achieving 100% conversion of methyl stearate with 100% selectivity toward n-heptadecane (C17) and n-octadecane (C18) (reaction conditions: 150°C, 4 h, 2.5 MPa H2). Moreover, the catalyst also shows excellent hydrogenation activity toward various fatty acids or esters, including methyl palmitate, stearic acid, and palmitate at low temperatures. The Re0.25-Ru/C catalyst showed consistent recycling performance over 9 cycles. The decline in catalytic performance of the catalyst was primarily caused by a reduction in ReOx content, resulting in a decrease in acid site concentration. Consequently, there was reduced adsorption of H2 and oil on the catalyst.
研究领域:
催化化学
·
可再生能源
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Frontiers of Chemical Science and Engineering
·
2023
·Vol. 17
·期 8
·1096-1108
·
IF 4.5
Hou De-Fa,Yuan Pan-Pan,Feng Zi-Wei,An Meng,Li Pei-Yao,Liu Can,Yang Ming-Bo
Derivatization has great potential for the high-value utilization of cellulose by enhancing its processability and functionality. However, due to the low reactivity of natural cellulose, it remains challenging to rapidly prepare cellulose derivatives with high degrees of substitution. The “cavitation effect” of ultrasound can reduce the particle size and crystalline index of cellulose, which provides a possible method for preparing cellulose derivatives. Herein, a feasible method was proposed for efficiently converting regenerated cellulose to cellulose oleate with the assistance of ultrasonic treatment. By adjusting the reaction conditions including ultrasonic intensity, feeding ratios of oleic acid, reaction time, and reaction solvent, a series of cellulose oleates with degrees of substitution ranging from 0.37 to 1.71 were synthesized. Additionally, the effects of different reaction conditions on the chemical structures, crystalline structures, and thermal behaviors were investigated thoroughly. Cellulose oleates with degrees of substitution exceeding 1.23 exhibited amorphous structures and thermoplasticity with glass transition temperatures at 159.8 to 172.6 °C. This study presented a sustainable and practicable method for effectively derivatizing cellulose.
研究领域:
材料科学
·
绿色化学
·
生物质转化
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2023
·
IF 8.2
Mengnan Han,Xiaozheng Li,Xuming Wang,Dexu Liu,Shuangqing Fu,Wenzhi Xu,Wei Li,Honglei Zhang
A polyhydroxyalkanoate (PHA) magnetic microsphere was designed for one-step purification and immobilization of a novel carbonyl reductase (RLSR5) from recombinant Escherichia coli lysate. The hydrophobic core of this microsphere was composed of a highly biocompatible polymer, poly(3-hydroxybutyrate- co -3-hydroxyhexanoate) (PHBHHx), in which magnetic Fe 3 O 4 particles were embedded during solvent evaporation. The hydrophilic shell of the fusion protein formed by PHA particle-binding protein (PhaP) and RLSR5 (PR) was expressed in recombinant E. coli . The magnetic core of Fe 3 O 4 @PHBHHx directly purified the hydrophilic shell from the E. coli lysate, and the two self-assembled to form Fe 3 O 4 @PHBHHx-PR through hydrophobic and hydrophilic interactions, eliminating the separation of the fusion protein. The microstructure, magnetic properties, morphology, size, and dispersion of Fe 3 O 4 @PHBHHx-PR were investigated by XRD, VSM, SEM, TEM, elemental mapping and DLS. It was found that Fe 3 O 4 @PHBHHx-PR correctly assembled, with a well dispersed spherical structure at the nanoscale and superparamagnetism properties. The amount of RLSR5 immobilized on PHA microspheres reached 121.9 mg/g. The Fe 3 O 4 @PHBHHx-PR was employed to synthesize (R )-tolvaptan with 99 % enantiomeric excess and 97 % bioconversion efficiency, and the catalyst maintained 78.6 % activity after 10 recovery cycles. These PHA magnetic microspheres are versatile carriers for enzyme immobilization and demonstrate improved stability and reusability of the free enzyme .
研究领域:
生物技术
·
酶工程
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）