JOURNAL OF ORGANIC CHEMISTRY
·
2022
·
IF 4.198
Jun Xu,Chao Peng,Bolin Yao,Hua-Jian Xu,Qiang Xie
This report describes a method for the deoxyfluorination of alcohols with KF as the fluorine source via in situ generation of highly active CF3SO2F. Diverse functionalities, including halogen, nitro, ketone, ester, alkene, and alkyne, are well tolerated. Mild conditions, a short reaction time, and a wide substrate scope make this method an excellent choice for the construction of C–F bonds.
研究领域:
有机化学
·
合成化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2021
·
IF 6.165
Liyu Chen,Jiaxin Yang,Youjian Yang,Jiangyu Yu,Xianwei Hu,Wenju Tao,Zhaowen Wang
The fluorine salt system is a potential electrolyte for the preparation of metals and alloys from metal oxides via molten salt electrolysis. The solubility of ZrO 2 in KF–AlF 3 –Al 2 O 3 molten salts (KF/AlF 3 molar ratio = 2.1–2.8, Al 2 O 3 content = 0–9 wt%) was measured using the isothermal saturation method in this study. The influence of temperature and electrolyte composition on ZrO 2 solubility was analyzed. The dissolution mechanism of ZrO 2 was then determined based on the analysis of X–ray diffraction and Raman spectroscopy results. The experimental results show that the solubility of ZrO 2 in the 2.4KF–AlF 3 molten salt at 1233 K could reach up to 6.62 wt%. Besides, the solubility of ZrO 2 increase with the increase of temperature, the decrease of KF/AlF 3 molar ratio and Al 2 O 3 content. X-ray diffraction and Raman spectroscopy analyses show that the dissolved ZrO 2 in KF–AlF 3 molten salts existed in the form of [Zr 2 O 2 F 6 ] 2− and [ZrF 6 ] 2− complex ions under melting and cooling conditions, respectively. And the dissolution process of ZrO 2 in KF–AlF 3 molten salts can be described using a mass transfer control model.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOM
·
2019
·Vol. 72
·期 1
·247-252
·
IF 2.305
Yan Hengwei,Liu Zhanwei,Ma Wenhui,Huang Liqiang,Wang Chengzhi,Liu Yingxin
The development of low-temperature aluminum electrolysis makes it possible to reduce energy consumption and greenhouse gas emissions. The KF-NaF-AlF 3 -based electrolyte is a promising low-temperature electrolyte for aluminum reduction. The liquidus temperatures of KF-NaF-AlF 3 electrolytes with a total cryolite ratio (CR t ) fixed at 1.3–2.0, and with different concentrations of NaF (with a step change of 5 mol.%), were investigated by the cooling curve method. The results showed that the liquidus temperature of KF-NaF-AlF 3 mixtures increases with the increase of the CR t , which has a bigger influence on the liquidus temperature than the traditional NaF-AlF 3 electrolyte currently used in aluminum smelters. When the content of NaF is 10–20 mol.%, the curves of the liquidus temperature vs. NaF content reach a peak. When the NaF content ranges from 30 to 40 mol.%, the liquidus temperature is relatively low (695–900°C). The precipitated order of the compounds in molten KF-NaF-AlF 3 electrolytes with a CR t of 1.3 is as follows: K 2 NaAlF 6 (or K 3 AlF 6 ) → Na 3 Al 5 F 14 → K 2 NaAl 3 F 12 → KAlF 4 .
研究领域:
材料科学
·
冶金学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS COMMUNICATIONS
·
2017
·
IF 3.33
Weibo Wu,Wenfeng Zhao,Chengjiang Fang,Zhongwei Wang,Tingting Yang,Hu Li,Song Yang
Selective hydrogenation of furfural (FUR) derivable from pentose is one of crucial route to upgrade biomass. In this work, a rapid and mild approach has been developed for the quantitative production of furfuryl alcohol from FUR at room temperature in several minutes as short as 5 min with the presence of readily available KF and polymethylhydrosiloxane (PMHS) that is a nontoxic and cheap liquid H-donor. This catalytic system was also active for the selective hydrogenation of various aldehydes in high yields, and could be recycled with little decrease of activity. In addition, the reaction mechanism was clarified by NMR spectra.
研究领域:
化学工程
·
生物质能
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2018
·Vol. 49
·期 4
·2071-2076
·
IF 1.834
Yan Hengwei,Yang Jianhong,Liu Zhanwei,Wang Chengzhi,Ma Wenhui
The cryolite ratio (CR) is an important parameter for the electrolyte in aluminum reduction cells. The measurement method for the CR of the KF-NaF-AlF 3 system acid (CR < 3) electrolyte by means of electrical conductivity was initially developed, and the formula for calculating the CR was deduced. This method has the advantages of simple operation and high precision. In addition, the relative standard deviations (RSD) of the measurement are < 1.2 pct, and the analysis error of the NaF or KF content has little effect on the determination of the CR.
研究领域:
冶金学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2014
·Vol. 4
·期 104
·60025-60033
·
IF 3.708
Juan Chen,Lihua Jia,Xiangfeng Guo,Lijun Xiang,Shengfeng Lou
A series of KF-modified Ca–Al hydrotalcite (xKF/HTL-M) solid base catalysts was prepared in methanol, and characterized by thermogravimetry analysis (TG-DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and carbon dioxide temperature-programmed desorption (CO2-TPD). The catalytic activity was investigated in the transesterification of ethylene glycol monomethyl ether (EGME) with methyl laurate (ML) to produce a novel biodiesel of ethylene glycol monomethyl ether monolaurate (EGMEML). The effect of the mass content of KF and the main reaction parameters such as EGME to ML molar ratio, amount of catalyst, reaction time and temperature on the yield of EGMEML were examined. The results indicate that a new phase of KCaF3 formed in xKF/HTL-M, and acted as the main active sites for the transesterification. In addition, xKF/HTL-M has excellent catalytic performance in the production of EGMEML. The highest yield of 97.7% was obtained over 24.7KF/HTL-M at EGME/ML molar ratio of 3.0, catalyst amount of 5 wt%, and reaction time of 4 h at 120 °C. Moreover, the catalyst displays a good stability and reutilization. A satisfactory yield of 90% was obtained after use for five consecutive cycles without significant deactivation. Finally, the activation energy (Ea) of the reaction of EGME with ML over 24.7KF/HTL-M was obtained as 27.11 kJ mol−1.
研究领域:
化学工程
·
催化材料
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Yifan Zhang,Xianwei Hu,Jiaxin Yang,Liyu Chen,Wenju Tao,Fengguo Liu,Zhongning Shi,Zhaowen Wang
Aluminum-vanadium intermediate alloy is a significant raw material for the fabrication of high-performance titanium alloys . In the present study, the electrochemical behavior of NaVO 3 on a solid molybdenum and liquid aluminum electrode is systematically investigated by cyclic voltammetry (CV) and square wave voltammetry (SWV) in the NaF-KF-AlF 3 molten salt and the formation mechanism of Al-V intermetallic compounds is emphatically analyzed. The results show that the electrochemical reduction of VO 3 − on the solid molybdenum electrode is a multi-step process and low-valence vanadium oxide (V 2 O 3 ) is obtained. In contrast, the electrochemical reduction of VO 3 − to V 2 O 3 on liquid aluminum electrode is through one-step process and the deposition potential is more positive than that on molybdenum electrode owing to the depolarization effect of the liquid aluminum electrode. In addition, Al-V intermetallic compounds are obtained on the liquid aluminum electrode by potentiostatic electrolysis. The reduction process of VO 3 − on the liquid aluminum electrode is described as: the electrochemical process is started by the direct electro-reduction of VO 3 − to V 2 O 3 , which is further converted to Al-V intermetallic compounds under the combined effect of electrochemical and aluminothermic reduction, with the latter playing a dominant role.
研究领域:
冶金学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2021
·Vol. 52
·期 5
·3490-3496
·
IF 2.47
Yan Hengwei,Huang Liqiang,Ma Wenhui,Liu Zhanwei,Qin Bo
The NaF-KF-AlF 3 -based electrolyte is a promising low-temperature electrolyte for aluminum reduction. The solubility and dissolution rate of alumina in NaF-KF-AlF 3 -LiF-CaF 2 melt with a cryolite ratio (CR) ranging from 1.5 to 1.8 were investigated by the rotating corundum disk method at 1073 K to 1153 K. The effect of the composition and temperature of the melt on the solubility and dissolution rate of alumina were discussed. The results show that the solubility and dissolution rate of alumina in the melt decrease with the increase of LiF and CaF 2 content, and the effect of LiF on the alumina solubility is greater than that of CaF 2 . The decrease of the CR and temperature lead to a marked reduction of the alumina solubility and alumina dissolution rate. The dissolution rate of alumina depends on the dissolution rate in the first 5 minutes. The alumina dissolution is a zero-order reaction in the first 5 minutes, and a first-order reaction in the next 30 minutes.
研究领域:
材料科学
·
冶金工程
✓ 已验证
产品关联
DOI
高影响因子
JOM
·
2019
·Vol. 72
·期 1
·239-246
·
IF 2.305
Peng Jianping,Wei Zheng,Di Yuezhong,Wang Yaowu,Sun Ting
NaF-KF-LiF-AlF 3 -based low-temperature electrolytes have attracted great interest because of their potential to optimize and improve current industrial aluminum production methods. In the present study, the saturated alumina solubility in quaternary NaF-KF-LiF-AlF 3 -based melts (total cryolite molar ratio \( {\text{CR}} = \left( {n_{\text{NaF}} + n_{\text{KF}} + n_{\text{LiF}} } \right)/n_{{{\text{AlF}}_{3} }} \) of 1.3) with both KF and LiF content of 0 mol.% to 20 mol.% were evaluated by measuring the weight loss of a rotating corundum disk over the temperature range of 800–920°C. The effects of the KF content, LiF content, and temperature on alumina solubility are discussed in detail. The results fit well with the following empirical equation within the temperature of 830–890°C: ω (Al 2 O 3 ) sat = A × ( t /1000) B , where A = 0.3101[KF] − 0.1254[LiF] − 0.0057[KF] 2 + 0.0028[LiF] 2 + 4.486, B = 0.3839[KF] + 0.0368[LiF] − 0.0140[KF] 2 + 0.0057[LiF] 2 + 4.913, and t is the temperature in Celsius. Alumina solubility diagrams at various temperatures are illustrated based on the empirical regression equation obtained. Finally, some problems and challenges preventing the application of these low-temperature melts in industry are discussed.
研究领域:
冶金学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Royal Society Open Science
·
2022
·Vol. 9
·期 9
·
IF 3.653
Haijun Cheng,Chang Yu,Hongyun Wang,Xiongmin Liu,Li Ma,Fang Lai
It has been a challenge to synthesize macrolide musk in excellent yields with high purity. KF-La/γ-Al2O3 catalyst was prepared from a highly basic mesoporous framework using a mild method. The prepared KF-La/γ-Al2O3 catalyst was employed for the synthesis of cyclopentadecanolide from methyl 15-hydroxypentadecanoate. The morphology and structure of prepared catalysts were characterized using XRD, TG-DTG, SEM, EDX, TEM, BET and CO2-TPD. The results revealed that the K3AlF6 and LaOF are produced on the surface of KF-La/γ-Al2O3, and LaO can promote the dispersion of KF on the surface of Al2O3. Catalysts pore size main distribution ranges between 10 and 30 nm, the maximum CO2 desorption temperature is 715°C when the La loading is 25%. Because F− ion has a higher electronegativity than O2− ion, the KF-promoted metal oxide (Al2O3 or/and La2O3) contained more strong basic sites, compared with that of the corresponding metal oxide. The yield of cyclopentadecanolide obtained at 0.5 g KF-25La/γ-Al2O3 catalyst and a reaction temperature of 190°C for 7 h were 58.50%, and the content after reactive distillation is 98.8%. The KF-La/γ-Al2O3 catalyst has a larger pore size and basic strength, which is more conducive to the macrolactonization of long-chain hydroxy ester.
研究领域:
有机化学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ChemPlusChem
·
2024
·
IF 3
Meng-Ge Wei,Hong-Ru Li,Liang-Nian He
Graphical A series of solid base KF/Mg-Fe bi-metal oxides were fabricated via supporting KF on Mg-Fe bi-metal oxides and calcination. When applied as catalyst to dimethyl carbonate (DMC) synthesis through transesterification of ethylene carbonate (EC) and methanol, this material can afford up to 88 % yield and 97 % selectivity toward DMC in the optimal conditions. It is worth noting that the catalyst can be easily separated by filtration and reused. A series of KF/Mg-Fe oxides were fabricated via the solid-state reaction between KF and Mg-Fe oxides. Especially, when 20 wt % KF was supported on the Mg-Fe bi-metal oxides and calcined at 400–600 °C, the solid material with more basic sites than the support itself was obtained. When applied as catalyst to dimethyl carbonate (DMC) synthesis through transesterification of ethylene carbonate (EC) and methanol, this material can afforded up to 88 % yield and 97 % selectivity toward DMC in 2 h under reflux conditions with the molar ratio of methanol to ethylene carbonate set at 8. It is worth noting that the catalyst was easily separated and reused, retaining at least 89 % catalytic activity during the first four recycles. Although an attenuated activity was still observed due to the inevitable filtration loss and dissolution, this solid base can still provide clues to the development recyclable catalyst in green synthesis of DMC.
研究领域:
化学工程
·
绿色化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SpringerPlus
·
2015
·Vol. 4
·期 1
·1-11
·
IF 0
Lou Shengfeng,Jia Lihua,Guo Xiangfeng,Wu Ping,Gao Lianbing,Wang Jianjun
Diethylene glycol monomethyl ether monolaurate (DGMEML) was synthesized via the reaction of diethylene glycol monomethyl ether (DGME) with methyl laurate (ML) by a new solid base catalyst of KF/CaO/AC, which was prepared by impregnation method using active carbon as carrier. The catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), nitrogen physisorption-desorption and Hammett indicator methods; the effect of the mole ratio of KF to CaO, DGME to ML molar ratio, amount of catalyst, reaction time and temperature on the yield of DGMEML were studied; and the relationship between the structure of the catalyst and the yield of DGMEML was investigated. The formed KCaF3 and K2O were acting as the main active components in the catalytic transesterification; the highest yield of 96.3 % was obtained as KF-to-CaO molar ratio of 2.0, DGME to ML molar ratio of 4.0, catalyst amount of 5 wt%, and reaction time of 30 min at 75 °C; and the catalyst displayed good stability in the transesterification.
研究领域:
化学工程
·
催化材料
✓ 已验证
DOI
PubMed
危险品化学品经营许可证（带存储）