TALANTA
·
2013
·
IF 3.498
Min Li,Jiaheng Zhang,Yubo Li,Bing Peng,Wenfeng Zhou,Haixiang Gao
A novel and facile microextraction technique, termed as ionic liquid-linked dual magnetic microextraction (IL-DMME), was developed for the determination of pyrethroids in honey samples. The distinct advantage of the proposed method is that high recoveries can be readily achieved through the combination of dispersive liquid–liquid microextraction (DLLME) and dispersive microsolid-phase extraction (D-μ-SPE) with the aid of synthetic ionic liquid and non-modified magnetic nanoparticles (MNPs), respectively. In the first DLLME step, [C 6 MIM]NTf 2 was used to extract the pyrethroids without the addition of any toxic dispersive solvent. In the following D-μ-SPE steps, non-modified MNPs were added to retrieve the ionic liquid. The effect of different variables on the extraction efficiency was studied simultaneously using the response surface methodology. The Plackett–Burman design was first employed to screen for the variables that significantly affected the extraction efficiency. Central composite design (CCD) was then introduced to optimize the significant factors using a polynomial fit. The optimal experimental conditions obtained from this statistical evaluation included: ionic liquid volume, 75 μL; S-BaFe quantity, 60 mg; sonication time, 4 min; vortex time, 100 s; desorption time, 150 s; and no addition of salt. Under the optimal conditions, good linearity in the range of 0.5 μg L −1 –500 μg L −1 , repeatability (RSD 1.1–3.8%), low LODs (0.03–0.05 μg L −1 ) and good recovery (86.7–98.2%) were obtained. Finally, the developed method was evaluated for the extraction and determination of four pyrethroids in real honey samples.
研究领域:
分析化学
·
食品科学
✓ 已验证
DOI
高影响因子
BIOTECHNOLOGY & BIOTECHNOLOGICAL EQUIPMENT
·
2018
·
IF 1.227
Zhilei Fu,Baoguo Sun,Xiuting Li,Guangsen Fan,Chao Teng,Ahmad Alaa,Yingmin Jia
A yeast that produces high levels of ethyl acetate was isolated and purified from Laobaigan Daqu by traditional microbial methods and was identified as Wickerhamomyces anomalus by its morphology and 26S rDNA D1/D2 sequence. This strain, YF1503, greatly tolerated ethanol and ethyl acetate. The optimal conditions for producing high levels of ethyl acetate were identified using single factor experiments and response surface methodology. Under these fermentation conditions, strain YF1503 produced 17.35 g/L ethyl acetate, the highest level that has been reported. The presence of alcohol acyltransferase (AAT) activity (8.63 U/L) and changes in the concentrations of ethanol and ethyl acetate in the fermentation broth indicate that strain YF1503 synthesises ethyl acetate using the acyltransferase pathway.
研究领域:
微生物学
·
发酵工程
·
食品科学
✓ 已验证
DOI
高影响因子
ENERGY & FUELS
·
2012
·
IF 2.721
Hualiang Zuo,Qiying Liu,Tiejun Wang,Longlong Ma,Qi Zhang,Qing Zhang
Catalytic hydrodeoxygenation (HDO) of vegetable oils to renewable alkane-type biofuels has attracted more and more concern in recent years. However, the presently used catalysts were mainly focused on the sulfided CoMo and NiMo catalysts, which inevitably posed sulfur contamination in final products. Therefore, exploring nonsulfured catalyst for this processing is of fundamental importance, but it is still an open challenge. In this paper, we prepared the sulfur free Ni supported on SiO2, γ-Al2O3, SAPO-11, HZSM-5, and HY by incipient wetness impregnation and tested the catalytic performance in HDO of methyl palmitate. Alkanes with long carbon chains were mainly produced with two possibly parallel approaches: hydrogenation of hexadecanal to hexadecanol, followed by dehydration/hydrogenation to C16 alkane and decarbonylaton/decarboxylation of hexadecanoic acid to C15 alkane. The acidity of catalysts significantly influenced their catalytic performance, and the Ni/SAPO-11 catalysts with weak and medium acidity showed superior properties to the other catalysts due to the synergistic effect of metal Ni and acidic support. The maximum yield of 93% for C15+ alkanes was observed over 7 wt % Ni/SAPO-11 under the mild reaction conditions of 493 K and 2 MPa, indicating its promising application in this reaction.
研究领域:
催化化学
·
可再生能源
✓ 已验证
DOI
高影响因子
Journal of CO2 Utilization
·
2020
·
IF 5.993
Zijie Shi,Qian Su,Ting Ying,Xin Tan,Lili Deng,Li Dong,Weiguo Cheng
Synthesis of cyclic carbonates via cycloaddition reaction by means of CO 2 and epoxides has been thought as an effective method for relieving global warming together with resource shortage. In order to elevate the utilization ratio of ionic liquids and separate catalysts easily after reaction, multi-site ionic liquids were designed and then immobilized on SBA-15 for the conversion of CO 2 into cyclic carbonates. By combining the advantages of multiple sites and mesoporous channel, in this work, a certain amount of ionic liquids with multiple active sites were firmly immobilized on modified SBA-15. Among all the immobilized ionic liquids, [IMCA] 2 Br 2 @SBA-15 presented the best catalytic activity. The result showed high yield (97.4 %) and almost 100 % selectivity of propylene carbonate, which was close to equivalent molar bulk ionic liquids. This superiority could be attributed to the sufficient dispersion of multiple active sites of ionic liquids after being immobilized, enabling efficient use of ionic liquids. Furthermore, the catalyst showed good recyclability after five cycles. By characterization and DFT calculation, the synergistically catalytic mechanism based on multiple sites was proposed.
研究领域:
化学工程
·
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
POLYMER BULLETIN
·
2018
·Vol. 76
·期 6
·3093-3112
·
IF 1.589
Zhang Xiaoyong,Liu Huihui,Yue Lipei,Bai Yongping,He Jinmei
In the area of pressure-sensitive adhesives (PSAs), acrylic PSAs have been successfully applied in many fields, including self-adhesive tapes, sign labels, carrier-free tapes, double-sided tapes and protective films, but applications of heat-resistant acrylic PSAs are relatively rare. In this study, the thermal stability of acrylic polymer containing maleimide (Mal) functional groups has been investigated. The PSAs were synthesized by acrylic monomers and Mal through copolymerization. The influence of Mal on the viscosity, molecular weight ( M w , M n ), glass transition temperature, thermogravimetric analysis and contact angle of acrylic PSAs was also studied. The adhesion performance and thermal stability of acrylic PSAs could be significantly enhanced by increase in Mal content of the synthesized resin. After 3 h of treatment in drying oven at 170 °C, the modified PSAs can be peeled (180°) off from the substrate without residues on substrate surface at room temperature, while the non-modified acrylic PSAs possessed residues after treatment from 110 °C. The maximum 180° peel strength of modified PSA films was 12.7 N/25 mm when the content of Mal was 7.5 wt%.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
ACS Omega
·
2019
·
IF 2.584
Mei Li,Haiyang Ding,Xiaohua Yang,Lina Xu,Jianling Xia,Shouhai Li
A tung-oil-based polyphenol (ATOM), containing the phenolic hydroxyl group, was synthesized from tung oil and 4-maleimidophenol by the Diels–Alder addition reaction. Then self-healing thermosetting polyurethanes were prepared from ATOM and the polyurethane prepolymer. The chemical structure and cross-link network were confirmed by Fourier transform infrared spectroscopy (FTIR) and swelling tests. The products partially dissolved in trichlorobenzene when the temperature rose to 110 °C. Temperature-variable FTIR confirmed that the phenolic urethane starts to partially dissolve at 100 °C, which can be explained by the experimental phenomenon in swelling tests. Tensile property analysis showed that the broken and healed thermosets maintained about 46–64% of their original tensile strengths and 81–88% of their original elongations at break, respectively.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
Catalysts
·
2015
·Vol. 6
·期 1
·6
·
IF 2
Jie Fu,Dong Sheng,Xiuyang Lu
Four types of nickel catalysts supported on aluminum oxide (Ni/Al2O3) with different nickel loadings were synthesized using the co-precipitation method and were used for the hydrogenation of levulinic acid (LA) to prepare γ-valerolactone (GVL). The synthesized Ni/Al2O3catalysts exhibited excellent catalytic activity in dioxane, and the activity of the catalysts was excellent even after being used four times in dioxane. The catalytic activity in dioxane as a solvent was found to be superior to the activity in water. Nitrogen physisorption, X-ray diffraction, and transmission electron microscopy were employed to characterize the fresh and used catalysts. The effects of the nickel loading, temperature, hydrogen pressure, and substrate/catalyst ratio on the catalytic activity were investigated.Keywords:nickel supported on aluminum oxide;γ-valerolactone;levulinic acid;hydrogenation;dioxane
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2021
·
IF 4.759
Yingying Shi,Meiling Qi
This work presents the investigation of two aliphatic polycarbonate diols (CAPC and HAPC) as the stationary phases for capillary gas chromatography (GC). The CAPC and HAPC capillary columns showed moderate polarity and high column efficiency of 3704 – 4545 plates/m measured by n-octanol and naphthalene at 120 °C. It was found that despite their similar chemical compositions, CAPC and HAPC differ largely in their selectivity towards the isomers of alkanes, methylpyridines and xylenes. As demonstrated, the CAPC column exhibits advantageous comprehensive performance over the HAPC column and the commercial PEG column. Particularly, the CAPC column exhibits higher resolving performance towards the isomers indicated above and the Grob mixture than the HAPC column. Also, it shows distinct advantages over the PEG column in separating the Grob mixture, the isomers of diethylbenzenes and cymenes, and practical analysis of chemical products and the essential oil from the leaves of Rhododendron dauricum L. Additionally, the CAPC column has excellent repeatability and reproducibility on analyte retention times with the relative standard deviation (RSD) values in the range of 0.05% – 0.08% for run-to-run, 0.12% – 0.19% for day-to-day and 2.6% – 4.9% for column-to-column, respectively. Its applications to purity test of chemical products and GC–MS analysis of the essential oil demonstrate its promising future for practical GC analyses.
研究领域:
分析化学
·
色谱学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Food Measurement and Characterization
·
2021
·Vol. 15
·期 6
·5345-5359
·
IF 2.431
Zhang Mingjun,Chen Yu,Wei Qunshu,Li Jianbin
The effect of applying an electrostatic field treatment to rum and its underlying reaction mechanism based upon a model system were investigated in this study. A field intensity of 1 kV·cm −1 and processing time of 30 min were the optimal treatment conditions, the content of (desirable) ester was increased to 219.57 ± 4.61 μg·mL −1 , and the content of (undesirable) fusel oil was decreased to 643.37 ± 15.26 μg·mL −1 , compared with the control (208.42 ± 2.31 μg·mL −1 and 707.04 ± 2.21 μg·mL −1 , respectively). In addition, Odorant Activity Value (OAV) analysis showed that there were 15 main flavor components (OAV > 1) in rum, and the concentrations of 13 flavor components were increased after 1 kV·cm −1 electrostatic field treatment, indicating that the flavor quality of rum was improved. When the electrostatic field intensity was 0.5, 1, and 2 kV·cm −1 , the rate constant (k) of the esterification reaction increased in the ethanol-acetic acid model system, and the activation energy decreased from 47.7 kJ·mol −1 to 46.1, 40.6 and 38.6 kJ·mol −1 , respectively. This showed that the electrostatic field treatment was helpful to the esterification reaction in the rum simulation system. 1 H NMR results showed that δET-OH, δH-OH, δCH 3 , and δCH 3 in the ethanol–water model system were all increased when the electrostatic field strength was 0.5, 1, 2, and 4, respectively. This showed that the electrostatic field treatment promoted the hydrogen bond association between ethanol and water molecules in the rum simulation system. Therefore, the maturation process in rum was accelerated and the quality of the rum was improved by electrostatic field treatment.
研究领域:
食品科学
·
化学工程
✓ 已验证
DOI
高影响因子
Water
·
2021
·Vol. 13
·期 23
·3338
·
IF 3.103
Yunjie Ma,Xin Gao,Yang Ruan,Hang Cui,Li Zhang,Wei Zhang,Shaoyan Wang
Resin based covalent organic framework material was used as filler for solid phase extraction (SPE), and the solid phase extraction effect was compared with that of traditional COF material (TpBD COFs). The enrichment capacity of four phthalate esters (dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate) in beverage samples was investigated by SPE. Adsorption experiments showed that the kinetic adsorption behavior of COF materials for phthalate esters (PAEs) was more consistent with the quasi-second-order kinetic adsorption model, and the static adsorption behavior is more in line with the Freundlich isothermal adsorption model. Solid phase extraction experiments proved that the SPE column prepared with two COF materials as adsorbents had good adsorption effects, high recovery (water: 97.99–100.56% and beverage: 97.93–100.23%) and were reusable (50 cycles), which could meet the requirements for trace detection of phthalate ester. It was found that the solid phase extraction effect was better than the four types of commercial SPE columns. The new COF material reduced the cost of monomer use and provided the possibility for its industrial production. Meanwhile, it also provided a new feasible scheme for enriching trace phthalate esters in practical samples.Keywords:resin-based COFs;phthalate esters;solid phase extraction;trace analysis
研究领域:
分析化学
·
环境科学
✓ 已验证
DOI
高影响因子
ACS Omega
·
2024
·
IF 3.7
Jinfeng Zheng,Jianbo Tang,Shenhao Jin,Hao Hu,Zhi-Jiang Jiang,Jia Chen,Jian-Fei Bai,Zhanghua Gao
An efficient method has been developed for the synthesis of α-deuterated α-amino esters via hydrogen isotope exchange of α-amino esters in D2O with 2-hydroxynicotinaldehyde as a catalyst under mild conditions. This methodology exhibits a wide range of substrate scopes, remarkable functional group tolerance, and affording the desired products in good yields with excellent deuterium incorporation. Notably, the ortho-hydroxyl group and the pyridine ring of the catalyst play a crucial role in the catalytic activity, which not only stabilizes the carbon-anion intermediates but also enhances the acidity of the amino esters’ α–C–H bond.
研究领域:
有机化学
·
合成化学
✓ 已验证
DOI
PubMed
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2020
·Vol. 39
·期 4
·493-500
·
IF 3.154
Meng Xiao-Yu,Li Yi,Yao Shu-Fang,Wei Xue-Wei,Ye Hai-Mu
Spherulites are the most common crystalline morphology and thus the visual expression of crystal structures for polymers. The diversified patterns have provided intuitive morphology probes for various crystallization behaviors, while the correlations between them are still needed to be enriched. In this work, the complicated spherulitic morphology of poly(propylene fumarate) (PPF), which is sensitive to crystallization temperature, is investigated. PPF melt, respectively, crystallizes into rough spherulites, regularly banded spherulites, and spherulites containing both two kinds of morphology at low, high, and mediate temperatures. By systematically assaying, it is clear that the growth axis along the radial direction changes from a -axis to b -axis as the crystallization temperature increases, which leads to the formation of unique crystallization-temperature-dependent spherulites. Based on detailed characterization of Fourier transform infrared spectroscopy, the packing state of the specific hydrogen bonds of “C=C-H⋯O=C-C=C” in PPF crystal lattices is determined, and furthermore, the mechanism for temperature-dependent selection of growth axes for PPF spherulites in melt is reasonably speculated.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）