GREEN CHEMISTRY
·
2023
·
IF 9.8
Tan Li,Jing Su,Linjia Yin,Xiangkun Zhang,Cong Wang,Xinbao Li,Jing Zhang,Kaige Wang
A Cu-based catalyst was developed for one-step solvent-free synthesis of aviation biofuel from biomass-derived ketones, including acetone, cyclopentanone, cyclohexanone, and 2-pentanone. Under the optimal working conditions, the conversion rate of acetone, cyclopentanone, cyclohexanone and 2-pentanone of 100% can be achieved by using Cu/Al2O3. 79.7 c% maximum carbon yield of liquid hydrocarbons with 89.5% selectivity of aviation biofuel was obtained under the conditions of 1.0 MPa H2, 280 °C, and 2 h−1 WHSV. The effects of the calcination temperature on the acidity and basicity of the catalyst, as well as the valence and dispersion of Cu species, were investigated. Based on DFT calculations and in situ DRIFTS results, the preferred adsorption of carbonyl groups and efficient dissociation of hydrogen on Cu+ increased the local concentration of H and feedstock on the catalyst surface, accelerating the rate-determining step that predominated on Cu0. The synergistic effect of Cu0 and Cu+ enhanced the formation of aviation biofuel.
研究领域:
催化
·
化学工程
·
可再生能源
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
THERMOCHIMICA ACTA
·
2018
·
IF 2.189
Feng Bao,Lishuai Zong,Nan Li,Yuanyuan Song,Yunxing Pan,Jinyan Wang,Xigao Jian
In this study, a series of poly(phthalazinone fluorenyl ether ketone ketone) (PPFEKK) copolymers were designed and synthesized via nucleophilic aromatic substitution polymerization of 1,4-bis(4-fluorobenzoyl)benzene (BFBB), 4-(4-hydroxyphenyl)(2 H)-phthalazin-1-one (DHPZ) and 9,9-bis(4-hydroxyphenyl)fluorene (BHPF) to investigate the effects of bulky fluorene units on the processability and thermal degradation behavior of the polymers. The structures of the PPFEKKs were investigated and confirmed by FTIR, 1 H NMR, wide-angle X-ray diffraction (WAXD) and gel permeation chromatography (GPC) techniques. Traditional thermal measurements showed that the T d 5% and T d 10% values of the copolymers increased as the content of BHPF units increased from 0 to 100 mol%, while their glass transition temperatures gradually decreased. The rheological measurements showed that the processability of the copolymers significantly improved upon incorporation of BHPF units; the poly(aryl ether)s were less viscous and thus more processable. The thermal degradation kinetics were clarified using TGA with Kissinger’s method. The copolymer undergoes two thermal degradation processes: as the content of BHPF units in the copolymers increased from 0 to 100 mol%, the activation energy of the first degradation reaction increased from 228 to 254 kJ mol −1 , and the activation energy of the second degradation reaction increased from 271 to 298 kJ mol −1 . The resulting films displayed excellent tensile strength (higher than 76 MPa), and their Young’s modulus values were inversely proportional to their BHPF contents. Dynamic mechanical analysis showed storage modulus values at 30 °C of approximately 2662, 2826, 2698, 2791 and 2830 MPa for the prepared polymers. Furthermore, the PPFEKKs were soluble in a variety of organic solvents, making them suitable for film casting.
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF DAIRY SCIENCE
·
2023
·
IF 3.5
Yanmei Xi,Sana Ikram,Tong Zhao,Yiwei Shao,Ruirui Liu,Fuhang Song,Baoguo Sun,Nasi Ai
ABSTRACT Flavor sensation is one of the most prevalent characteristics of food industries and an important consumer preference regulator of dairy products. So far, many volatile compounds have been identified, and their molecular mechanisms conferring overall flavor formation have been reported extensively. However, little is known about the critical flavor compound of a specific sensory experience in terms of oxidized off-flavor perception. Therefore, the present study aimed to compare the variation in sensory qualities and volatile flavors in full-fat UHT milk (FFM) and low-fat UHT milk (LFM) samples under different natural storage conditions (0, 4, 18, 25, 30, or 37°C for 15 and 30 d) and determine the main component causing flavor deterioration in the FFM and LFM samples using sensory evaluation, electronic nose, and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). In addition, the Pearson correlation between the volatile flavor components and oxidative off-flavors was analyzed and validated by sensory reconstitution studies. Compared with the LFM samples, the FFM samples showed a higher degree of quality deterioration with increased storage temperature. Methyl ketones of odd carbon chains (i.e., 2-heptanone, 2-nonanone, 2-undecanone, 2-tridecanone, and 2-pentadecanone) reached a maximum content in the FFM37 samples over 30 d storage. The combined results of the Pearson correlation and sensory recombination study indicated that 2-heptanone, 2-nonanone, and 2-undecanone conferred off-flavor perception. Overall, the present study results provide potential target components for detecting and developing high-quality dairy products and lay a foundation for specific sensory flavor compound exploration in the food industry.
研究领域:
食品科学
·
感官评价
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
HIGH PERFORMANCE POLYMERS
·
2020
·
IF 1.568
Dalin Dong,Yuezhen Bin,Xigao Jian
Meta-poly(phthalazinone ether ketone ketone) copolymers with 4,4′-dihydroxybiphenyls (meta-PPBEKK) was synthesized with 4,4′-dihydroxybiphenyls (BP), 1,3-bis(4-fluorobenzoyl)benzene (meta-DFKK) and 4-(4-hydroxyphenyl)-2,3-diazaphthalene-1-one (DHPZ). The copolymers are high-temperature resistant and have good solubility in many solvents. With increasing molar ratio of BP to meta-DFKK from 0 to 0.2, the addition of BP improves number-average molecular masses, intrinsic viscosity, mechanical properties and fluidity of meta-PPBEKKs. When the molar ratio of BP to meta-DFKK is 0.2, the intrinsic viscosity reaches 1.14 dL g−1, the number-average molecular mass reaches 44700 g mol−1, the maximum thermal elongation ratio reaches 14 with strength of 127.1 MPa and Young’s modulus of 2.4 GPa. With increasing molar ratio of BP to meta-DFKK from 0 to 0.2, meta-PPBEKKs have improved comprehensive properties, and make sense in many fields.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2016
·
IF 4.012
Mazloom Shah,Fan Zhang,Ashfaq Ahmad
The catalytic conversion of substituted and unsubstituted cyclohexanones to the corresponding enones and aromatic alcohol catalyzed by Pd, Pd-1, Pd-cube, Cu, Ni, Ag@Pd and Ni-Sn nanocatalysts has been studied in the presence of O 2 as the oxidant without using any additives i.e. acid or base or ligand. The optimization of experimental parameters for dehydrogenation of cyclohexanones was established to achieve maximum yield of the product by using Pd nanocatalyst. The conversion of cyclohexanone, cyclohexenone, 3-methyl cyclohexanone and 3-methyl cyclohexenone catalyzed by Pd nanocatalyst at 80 °C, 10 atm O 2 pressure after 24 h, led to a 79%, 49%, 62% and 25% yields of desired products, respectively. Then, the conversion of substituted and unsubstituted cyclohexanones investigated in the presence of various nanocatalysts i.e., Pd-1, Pd-cube, Cu, Ni, Ag@Pd and Ni-Sn nanoparticles and was compared their percentage yields.
研究领域:
化学
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2014
·Vol. 406
·期 28
·7379-7387
·
IF 3.578
Wang Jing,Liu Shu,Ma Bing,Chen Lina,Song Fengrui,Liu Zhiqiang,Liu Chun-ming
Xanthine oxidase (XOD) catalyzes the metabolism of hypoxanthine and xanthine to uric acid, the overproduction of which could cause hyperuricemia, a risk factor for gout. Inhibition of XOD is a major treatment for gout, and biflavonoids have been found to act as XOD-inhibitory compounds. In this study, ultrafiltration liquid chromatography with photodiode-array detection coupled to electrospray-ionization tandem mass spectrometry (UF-LC-PDA–ESI-MS) was used to screen and identify XOD inhibitors from S. tamariscina . High-performance counter-current chromatography (HPCCC) was used to separate and isolate the active constituents of these XOD inhibitors. Furthermore, ultrahigh-performance liquid chromatography (UPLC) and triple-quadrupole mass spectrometry (TQ-MS) was used to determine the XOD-inhibitory activity of the obtained XOD inhibitors, and enzyme kinetics was performed with Lineweaver–Burk (LB) plots using xanthine as the substrate. As a result, two compounds in S. tamariscina were screened as XOD inhibitors: 65.31 mg amentoflavone and 0.76 mg robustaflavone were isolated from approximately 2.5 g S. tamariscina by use of HPCCC. The purities of the two compounds obtained were over 98 % and 95 %, respectively, as determined by high-performance liquid chromatography (HPLC). Lineweaver–Burk plot analysis indicated that amentoflavone and robustaflavone were non-competitive inhibitors of XOD, and the IC
50 values of amentoflavone and robustaflavone for XOD inhibition were 16.26 μg mL −1 (30.22 μmol L −1 ) and 11.98 μg mL −1 (22.27 μmol L −1 ), respectively. The IC
50 value of allopurinol, used as the standard, was 7.49 μg mL −1 (46.23 μmol L −1 ). The results reveal that the method for systematic screening, identification, and isolation of bioactive components in S. tamariscina and for detecting their inhibitory activity using ultrafiltration LC–ESI-MS, HPCCC, and UPLC–TQ-MS is feasible and efficient, and could be expected to extend to screening and separation of other enzyme inhibitors.
ᅟ
研究领域:
药理学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
STEROIDS
·
2020
·
IF 1.948
Bairen Du,Jingjing Zhang,Yanjie Dong,Junwei Wang,Longwen Lei,Rengfei Shi
A novel method for determining the testosterone/epitestosterone concentration ratio in human urine was established by capillary electrophoresis with diode-array detector. The urine samples were firstly purified by the solid extraction. The optimal experimental conditions were: running buffer pH = 4.74, 15.0 mmol L −1 HAc-NaAc, separation voltage 25 kV, temperature 25 °C, sample injection pressure 3.43 × 10 3 Pa, and duration 10 s. The testosterone and epitestosterone linear range were determined as 8.0–960.0 ng mL −1 , respectively. The testosterone and epitestosterone detection limits were determined as 4.6 and 4.5 ng mL −1 , respectively. The relative standard deviation was less than 0.36%.
研究领域:
分析化学
·
医学检验
·
运动科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2022
·
IF 6.449
Qingjie Wang,Yang Jiang,Xinyu Mao,Wanwen Yu,Jinkai Lu,Li Wang
Age affects the content of flavonoids in ginkgo ( Ginkgo biloba L.) leaves, such that only 1-to-5-year-old ginkgo leaves are suitable for the extraction of medicinal compounds. Nevertheless, the relationship between age and flavonoids in ginkgo leaves is unclear. In this study, we compared 1-to-7-year-old ginkgo trees, and found that the flavonoid content decreased with age. The total flavonol aglycones content of 1-year old ginkgo was 9.88 ± 0.27 mg/g, significantly higher than those of 4- and 7-year-old gingko, and there was a marked difference in quercetin content. Next, we extensively compared the transcriptome and metabolome in leaves of 1-, 4-, and 7-year-old ginkgo. Metabolome profiles showed that flavonoid metabolites were the most abundant in different metabolities, and 82 % of the flavonoids exhibited a decreasing trend with increasing age. Downregulation of key structural genes (chalcone synthase, CHS ; flavanone 3-hydroxylase, F3H ; flavonol synthase , FLS ) in the flavonoid biosynthesis pathway may explain the decreased flavonoid content with age. Furthermore, GO and KEGG analysis revealed photosynthesis- and hormone-related genes were downregulated with increasing age, implying that photosynthesis, salicylic acid, and jasmonic acid influence the flavonoid content. These results provide a theoretical basis for leaves ginkgo seedlings and new clues for understanding how age regulates flavonoids.
研究领域:
植物学
·
药理学
·
分子生物学
·
植物生理学
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2021
·
IF 9.127
Bengui Zhang,Minghui Zhao,Qian Liu,Xueting Zhang,Yanshi Fu,Enlei Zhang,Guosheng Wang,Zhigang Zhang,Xinchen Yuan,Shouhai Zhang
This reported study describes an effort to produce durable membranes for high performance vanadium redox flow batteries (VRFB). The reported novel, positively-charged membranes are derived from pyridine-containing poly(aryl ether ketone ketone) (PyPEKK) and are prepared using an environmentally-friendly method. Basic pyridine groups on the polymer backbone serve as proton acceptor sites and these electron-rich, polar sites establish proton transport channels, which provide PyPEKK membranes with an area resistance as low as 0.15 Ω cm 2 , which is comparable to Nafion 212 (0.13 Ω cm 2 ). The novel PyPEKK membranes have low vanadium permeability due to the Donnan repulsion between the positively charged protonated pyridine groups and the vanadium ions . Consequently, the resulting dense structure of these PyPEKK membranes produce an impressive energy efficiency in VRFB (89.0% at 80 mA cm −2 , and 80.1% at 180 mA cm −2 ). The PyPEKK membrane exhibit stable performance of 1000 cycles and low oxidation . These PyPEKK membranes are highly promising candidates for VRFB application.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
ORGANIC & BIOMOLECULAR CHEMISTRY
·
2022
·Vol. 20
·期 27
·5412-5415
·
IF 3.89
Yan-Zuo Chen,Neng Wang,Zong-Rui Hou,Xian-Li Zhou,Xiaohuan Li,Feng Gao,Ting Jiang
Herein, we report that α,β-unsaturated ketones could be obtained by palladium-catalyzed ring-opening of mono-substituted cyclopropyl ketones efficiently and systematically. (E)-1-Arylbut-2-en-1-ones were generated from aryl cyclopropyl ketones stereoselectively in yields of 23–89% by the Pd(OAc)2/PCy3 catalytic system. The reaction exhibited stereoselectivity (only E products were found) and was suitable for both phenyl and heteroaryl cyclopropyl ketones.
研究领域:
有机化学
·
催化反应
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2023
·
IF 7.4
Zhihan Wu,Kuan Ding,Guiying Lin,Hongqi Sun,Shu Zhang
Ketonization of oxygenated compounds in pyrolytic products of biomass is an effective means for deoxygenation and upgrading of bio-oils. However, the ketonization potential of biomass-derived sugars and the mechanism underneath remain unclear. On this basis, a series of Fe doped CeO 2 catalysts were synthesized and employed for catalytic ketonization of xylan. Characterization of the catalysts proved the successful formation of the Fe-CeO x solid solution. Doping an appropriate amount of Fe (20–33%) ions on CeO 2 could obviously increase the number of oxygen vacancy and basic sites by up to 56.31% and 29.6%, respectively. During the catalytic reaction of xylan, pure CeO 2 exhibited a good ketonization ability during xylan pyrolysis, and the introduction of a certain amount of Fe further enhanced the ability. The highest yield of ketones was obtained by 33%Fe-CeO 2 , which was 38% higher than pure CeO 2 . The selectivity to linear ketones (acetone and 2-butanone) reached a maximum of 85% for 57%Fe-CeO x . Thus, oxygen-rich compounds had been converted to low oxygen containing and high-quality ketone components. Introducing Fe into CeO 2 favored the production of ethylene glycol rather than 2,3-dihydroxy propanal, and thus promoted the yield of acetone. This investigation provides fundamentals for the deoxygenation of biomass through catalytic ketonization, aiming at the production of value-added ketone products.
研究领域:
催化
·
化学工程
·
可再生能源
·
生物质转化
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR STRUCTURE
·
2024
·
IF 4
Qianqian Xing,Xiaoliang Jia,Shiyu Jia,Yongqin Qi,Yuqi Wang,Yingxiong Wang,Xianglin Hou
The traditional synthesis methods of cyclopropyl methyl ketone (CPMK) have some disadvantages such as low yield, slow reaction rate and unclear catalytic mechanism. To solve these problems, a new strategy is developed to synthesize CPMK from 5‑chloro-2-pentanone (CPE) using 1,8-diazabicyclo[5.4.0]undec‑7-ene (DBU). Experiment results show that the yield of CPMK reached a maximum of 96.5 % in DBU at 40 °C for 30min. The mechanism study shows that the hydrogen bond between DBU and CPE is the key to drive the deprotonation and cyclization of CPE. The hydrogen bond is formed between the N atom on C = N of DBU and the α-H on the methylene group associated with the carbonyl group on CPE. The catalyst DBU is converted into [DBUH] + Cl − , which can be reclaimed and recycled completely. The density functional theory (DFT) calculation confirmed the existence of molecular hydrogen bonds and proved that the hydrogen bond driving force is the key to the reaction. The hydrogen bond driven mechanism provides a new idea for the basic research of cyclization reaction.
研究领域:
有机化学
·
催化反应
✓ 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）