JOURNAL OF RARE EARTHS
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2022
·
IF 4.632
Junlian Wang,Wen Xu,Jianguo Cui,Guodong Xu,Yufu Chen,Peilong Wang,Ziyong Chang
Heavy rare earth element (HREE) separation has always been a great challenge. The kind of dialkylphosphinic acids is recognized as the third generation of organophosphorous acid extractants. However, detailed relationship between β -substituent (especially when it changes from H to methyl, and further to ethyl) and their extraction behaviors and selectivity for HREEs have rarely been reported. Besides, there are also few reports on effect of γ , δ -substituent on HREE extraction and separation. In this paper, we synthesized five and collected two dialkylphosphinic acids with different β , γ , δ -substituents (from H to ethyl). These extractants were divided into two groups to discuss their extraction behaviors and selectivity for HREEs: β -substituent group (P208, INET-1, P218, USTB-1 and P227) and γ , δ -substituent group (P218, P2132 and Cyanex 272). To evaluate and compare their extractabilities, P507 was used as a reference and Tm, Yb, Lu were extracted with 0.01 mol/L of these extractants from single Tm, Yb and Lu solutions (∼4 × 10 −4 mol/L) at different initial pH. Besides, pH 0.5 Tm , pH 0.5 Yb and pH 0.5 Lu values and their differences (ΔpH 0.5 Tm–Yb , ΔpH 0.5 Yb–Lu , ΔpH 0.5 Tm–Lu ) for each extractant were given to roughly evaluate their separation performance for Tm, Yb and Lu. To further investigate the selectivity of these extractants for HREEs, Tb, Dy, Ho, Er, Tm, Yb and Lu were extracted from their mixed solution with initial pH of 4.00 at phase ratio A/O of 2:1, 1:1 or 1:2. Their HREE separation performance is mainly discussed based on the adjacent HREE separation factors ( β N+1/N ) and their average value ( β T b − L u ¯ ).
研究领域:
化学
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材料科学
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DOI
高影响因子
Polymers
·
2020
·Vol. 12
·期 2
·261
·
IF 3.426
Yu Ji,Qiang Yao,Weihong Cao,Yueying Zhao
The intumescent process of sodium (substituted) phenolates has been studied. The generation of hydrogen radical via a homolytic cleavage of the Ar–H bond and the subsequent hydroarylation of phenolates to cyclohexadienes along with cyclization and elimination reactions of cyclohexadienes are critical steps in the base promoted intumescence of phenols. The substituents show great influence on the intumescence of phenolates. Phenolates substituted with a weak electron donating group enable intumescence while those with an electron withdrawing group or strong electron donating group suppresses intumescence. This distinction can be justified by both electronic and steric effects of substituents on the generation of hydrogen radical and the degree of hydroarylation.Keywords:alkali;intumescence;substituent;hydroarylation;phenolate
研究领域:
化学
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材料科学
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DOI
高影响因子
CRYSTAL GROWTH & DESIGN
·
2025
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IF 3.4
Yaqi Qin,Xiaoyu Feng,Jinkang Ma,Fanghao Xuan,Kaiwen Hu,Lifeng Cao,Dongwei Zhai,Bing Teng
Two novel chalcone crystals, 5MFTF (C15H11F3O2, P1) and 5MFTN (C14H11NO4, P1), were successfully synthesized by introducing trifluoromethyl and nitro substituents, respectively. Growth of the crystals was carried out by a slow evaporation solution method. The structures of the crystals were successfully verified by the results of 1H NMR, FT-IR, and powder XRD tests. The crystal stacking arrangements of 5MFTF and 5MFTN were characterized via a single-crystal X-ray diffraction (XRD) technique. The second-harmonic generation (SHG) measurements revealed that 5MFTF exhibited an SHG intensity 7.5 times that of potassium dihydrogen phosphate (KDP), while 5MFTN showed a SHG intensity 5.2 times that of KDP. The hyperpolarizability and FMOs were also calculated. In order to reveal the microscopic charge transfer mechanism in crystalline materials (5MFTF and 5MFTN), hole–electron analysis and interfragment charge transfer were calculated. 5MFTN crystal exhibited higher thermal decomposition temperatures compared to the other chalcone crystals (Tm ≈ 207 °C). All of these results indicate that the 5MFTF and 5MFTN crystals are promising for optical applications.
研究领域:
材料科学
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光学材料
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晶体工程
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非线性光学
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有机合成
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DOI
高影响因子
JOURNAL OF LUMINESCENCE
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2017
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IF 2.686
Mingguang Zhu,Youzhen Zhuo,Hongyu Guo,Fafu Yang,Jiabin Qiu
The first perylene liquid crystals bearing six peripheral alkyl substituents on both 1,6,7,12-bay positions and imides positions were designed and synthesized in yields of 72–77%. The studies on their mesomorphic behaviors suggested that they possessed good ordered hexagonal columnar mesophase with low phase transition temperatures and wide ranges of mesophase temperature in comparison with their precursors with chloric groups and the similar perylene liquid crystal with 4- tert -butylphenolic groups on bay positions. Their photophysical properties revealed that they also had higher fluorescence intensities and fluorescence quantum yields than that of their precursors with chloric groups and the similar perylene liquid crystal with 4- tert -butylphenolic groups on bay positions. The good fluorescence in both solution and solid film were observed for the first time for perylene liquid crystals. This research indicated that the introduction of long p -nonylphenol units on bay position is an effect strategy to obtain perylene liquid crystal with good liquid crystalline behavior and excellent fluorescent property.
研究领域:
材料科学
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化学
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DOI
高影响因子
POLYMER
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2011
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IF 3.829
Muhammad Naveed Anjum,Lihua Zhu,Zhihong Luo,Jingchun Yan,Heqing Tang
Optically active polyorthoanisidine, polyorthotoluidine, polyorthoethylaniline and polyorthochloroaniline were synthesized with chemical polymerization of corresponding monomers in aqueous medium by using d - or l -camphorsulfonic acid ( d - or l -CSA) as chiral dopant , ammonium persulfate as oxidant, and diaminodiphenylamine as initiator. By circular dichroism spectroscopic measurements, it was found that PANI exhibited generally a reversed chirality in comparison with the used chiral dopant, but the substituted PANIs had the same one as the chiral dopant. This revealed that the substituent at ortho position caused helical inversion of conformation in comparison with the parent PANI. Such effect was further confirmed by the influence of the copolymerization of aniline and its derivatives on the chirality of the copolymers . The effect of the substituent on the chirality of the copolymers was increased with the increase of the steric hindrance of the ortho substituent. A mechanism was proposed to explain the effects of steric hindrance on the chirality of PANIs. The clarified relationship between the steric hindrance and the chirality of the polymer can enable us to tailor the chiroptical properties of functional polymer materials for future application.
研究领域:
高分子化学
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材料科学
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2023
·
IF 6.2
Gao-yu Zhao,Shan Hu,Shu-chang Luo,Juan Lei,Yanfen Wei
To examine the electronic effect of substituents on the photocatalytic performance of PhC 2 Cu, two organometallic photocatalysts with either an F-atom (4F-P) or a CH 3 -group (4CH 3 -P) substituent at the phenyl ring para position were prepared by a facile one-step aqueous-phase method. Density functional theory calculations of the three organometallic photocatalysts (4F-P, P and 4CH 3 -P) revealed the substituent electronic effect on the frontier orbital energies and on the charge density at the Cu + ion. This study indicates that the introduction of the strongly electron-withdrawing F atom facilitates the effective separation of the photo-generated charge carriers, while the introduction of the electron-donating CH 3 group inhibits it. Consequently, the 4F-P photocatalyst exhibits greater photo-degradation activity compared to 4CH 3 -P and unsubstituted P. This investigation has shown that the introduction of a strongly electron-withdrawing substituent group is an effective strategy to improve the photocatalytic activity.
研究领域:
化学
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材料科学
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DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
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2025
·
IF 7.3
Le Ma,Yang Hou,Jun Nie,Xiaoqun Zhu
The introduction of substituents affects the planarity of the molecule, resulting in different physical and chemical properties. This study synthesized four one-component visible light photoinitiators with different substituents derived from 1-naphthylamine. They were amine-free (BTX), primary amine (BTX-A), secondary amine (BTX-MA), and tertiary amine (BTX-DMA). The photophysical and photochemical properties were explored using UV–visible absorption spectroscopy combined with DFT theory computational simulations. They had excellent absorption properties in the visible light range ( ε : 3200–6300 L mol −1 cm −1 ). The structure of amine substitutions in the initiators showed different redshift phenomena. The maximum absorption wavelength of BTX in the visible region is 388 nm; only a 7 nm red shift occurred for the maximum absorption wavelength of BTX-DMA. While BTX-A had a maximum absorption wavelength of red shifting by 41 nm， the red shift for BTX-MA was about 53 nm, and its UV absorption tail extended to 520 nm. This phenomenon was known to be the result of the combined effect of electronic donor and molecular planarity according to the DFT theoretical calculations. The photopolymerization kinetics of four initiators used for double bond monomers was investigated by real-time FT-IR. The results indicated that polymerization could occur for all the designed systems; the highest double bond conversion could reach 92 % when BTX-DMA was used as a visible-light photoinitiator for the monomer of 2-hydroxyethyl acrylate (HEA).
研究领域:
材料科学
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化学工程
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光学
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高影响因子
LIQUID CRYSTALS
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2013
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IF 1.959
Yiwei Xu,Xinbing Chen,Fengqi Zhao,Xuezhong Fan,Pei Chen,Zhongwei An
The synthesis and characterisation, and mesomorphic and photophysical properties of a new type of benzoxazole-terminated heterocyclic compounds, 2-(4ʹ-alkoxybiphenyl-4-yl)-benzoxazole derivatives (nB-x), are reported. For better understanding of the structure–property relationships, compounds bearing a variety of polar substituents in the 5-position of the benzoxazole moiety were prepared, including H (nB-H), NO2 (nB-N), CH3 (nB-M) and Cl (nB-C). Their phase transition behaviour was investigated by differential scanning calorimetry and polarising optical microscopy. In the case of carbon atoms in the alkoxy chain between 2 and 10 they exhibited enantiotropic smectic mesophases, for which the mesophase ranges were 101–175°C and 159–182°C on heating and cooling for nB-N, 5–63°C and 19–63°C for nB-H, 81–90°C and 78–96°C for nB-M, and 131–132°C and 131–132°C for nB-C, respectively. The effect of the length of the alkoxy chain on mesomorphic properties was studied. Compounds nB-N, nB-M and nB-C exhibited a much wider mesophase range either on heating or cooling than the corresponding nB-H series, which indicated that the substituent on the benzoxazole moiety was helpful in increasing the mesophase stability. Substituents with stronger electron-withdrawing properties gave a wider mesomorphic temperature domain, in the order NO2 > Cl > CH3 > H, which was similar to the effect of the substituents on the UV absorption bands of nB-x. The opposite effect was found for the corresponding Schiff base liquid crystals (nS-x). With the exception of nB-N, the nB-x series displayed intense photoluminescence emission in methylene chloride solution, with absorption maxima within the range 395–404 nm.
研究领域:
材料化学
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物理化学
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DOI
高影响因子
Molecular Catalysis
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2022
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IF 5.089
Jiacheng Zhang,Jieyu Zhou,Guochao Xu,Ye Ni
Kp ADH is a promising biocatalyst for the synthesis of chiral bulky-bulky alcohols. Substrate specificity toward diaryl ketone substrates with different substituents at phenyl group was investigated. The results reveal that the para -position of diaryl ketones plays important role in manipulating the stereoselectivity of Kp ADH. Two vital residues, E214 and T215, were identified through single-point mutagenesis, and saturation mutagenesis was performed to evaluate their contributions to the stereoselectivity. Furthermore, stereodivergent evolution of Kp ADH was achieved through combinatorial mutagenesis. Among them, E214I/T215S/S237A (ISA) and F161V/S196G/E214G (VGG) exhibited e.e. values of >99% ( S ) and 99% ( R ) toward [4-(trifluoromethyl)phenyl]-2-pyridinylmethanone ( 5a ), and e.e. values of >99% ( S ) and 98% ( R ) toward (4-methylphenyl)-2-pyridinylmethanone ( 6a ), respectively. Kinetic characterization and interaction analysis further prove that the eliminated side-chain collision and enhanced electrostatic interactions are mainly responsible for the increased catalytic efficiency and stereoselectivity. This study provides beneficial mutants with complementary stereoselectivity toward diaryl ketones with para -substituents and also provides guidance for the engineering of homologous alcohol dehydrogenases toward bulky-bulky ketones.
研究领域:
生物化学
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酶工程
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DOI
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
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2022
·
IF 3.656
Lei Ma,Feifei Zhang,Kunjie Li,Yingying Zhang,Zhiqiang Song,Li Wang,Jiangfeng Yang,Jinping Li
The capture of N 2 O from CO 2 by an adsorption-based mechanism remains a significant challenge due to their similar molecular sizes and physical properties. Although substituent engineering has been widely employed for the selectivity regulation and improvement of gas mixtures in metal-organic frameworks, its effect on N 2 O/CO 2 separation has yet not been explored. Herein, four isoreticular MTN-type metal-organic frameworks (MOFs) with different substituents (-H, –NH 2 , -Br or –NO 2 ) are reported for the capture of N 2 O from a N 2 O/CO 2 mixture. As revealed by isothermal measurements, thermodynamic studies and ideal adsorbed solution theory computations, the N 2 O/CO 2 separation potential can be effectively improved by an electron-donating group (-NH 2 ), whereas electron-withdrawing groups (-NO 2 or -Br) exhibit the opposite effect. Notably, MIL-101(Cr)–NH 2 exhibits, by far, the highest ideal adsorbed solution theory equilibrium adsorption selectivity of 1.91 for 50/50 N 2 O/CO 2 . The N 2 O/N 2 separation ability of the modified materials is also studied and functionalization with a -Br group yields an improved separation potential compared to the parent MIL-101(Cr) material. The strategy of using substituents to enhance the N 2 O/CO 2 separation efficiency of MOFs could also be extended to other porous materials for chemical separation processes.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2018
·Vol. 136
·期 6
·47039
·
IF 1.901
Shan Cao,Shouhai Li,Mei Li,Lina Xu,Haiyang Ding,Jianling Xia,Meng Zhang,Kun Huang
Phenolic hydroxyl gave thermal self-healing ability to phenolic polyurethanes in our previous study. To explore, the feasibility of preparing self-healing polyurethanes through polyphenols with different substituents. Urushiol, propyl gallate, catechol, and tert-butylhydroquinone were chosen for preparation of four phenolic polyurethanes, and the different factors at the structures of these polyphenols worked together led the different properties and self-healing ability. The peak temperatures of these four polyurethanes were determined by DSC in the following order: PTHFTDI-Urushiol < PTHFTDI-Catechol < PTHFTDI-Propyl gallate < PTHFTDI-Tert-butylhydroquinone. Variable-temperature FT-IR spectra displayed that PTHFTDI-Propyl gallate with electron-withdrawing substituent exhibited the lowest decomposition and healing temperatures. Meanwhile, based on TGA analysis, lower decomposition temperature suggested lower thermostability; and PTHFTDI-Urushiol with electron-donating substituent exhibited the best thermostability. At the same temperature, the healing abilities of the three polyurethanes were ranked as follows: PTHFTDI-Catechol < PTHFTDI-Urushiol < PTHFTDI-Propyl gallate. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47039.
研究领域:
材料科学
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化学
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DOI
高影响因子
CHROMATOGRAPHIA
·
2012
·Vol. 75
·期 23
·1347-1354
·
IF 1.195
Sun Baishen,Li Xiaofang,Jin Zhaolei,Tian Lili,Wang Fang,Liu Guihua,Tang Shouwan,Pan Fuyou
Four regioselectively modified amylose derivatives with three different substituents at the 2-, 3-, and 6-positions were prepared and their enantioseparations in HPLC were examined. Investigations indicated that the nature as well as the arrangement of the substituents significantly influenced their enantioseparations and each derivative exhibited characteristic chiral recognition. Amylose 2-benzoyl-3-(3,5-dimethylphenylcarbamate or 3,5-dichlorophenylcarbamate)-6-(( S )-1-phenylethylcarbamate) exhibited chiral resolving abilities comparable to the commercial available amylose tris(3,5-dimethylphenylcarbamate)-based column, Chiralpak AD and the racemic compounds shown in this study were most effectively resolved on these two derivatives. The influence of mobile phase on chiral resolution was also examined.
研究领域:
化学
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分析化学
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色谱技术
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DOI
高影响因子
危险品化学品经营许可证（带存储）