Bio-based polyurethanes(PUs)have been occurred a large attention nowadays.It was found to be an alternative to the petrochemical based materials to the fact of their weak environmental influence,availability,good pric...Bio-based polyurethanes(PUs)have been occurred a large attention nowadays.It was found to be an alternative to the petrochemical based materials to the fact of their weak environmental influence,availability,good price and biodegradability.In addition,the nature shows several bio-derived compounds as raw materials for the synthesis of polyols,including the vegetable oils,polyphenol,terpene,and other bio-renewable sources.With the aim to develop a new family of biobased polyurethanes(PUs)via vegetable oils,the elaboration of new Jojoba-based PUs was performed by catalyst-free polycondensation reaction of a synthesized Jojoba diol with various diisocyanates such us toluene diisocyanate(TDI)and isophorone diisocyanate(IPDI).All the compounds were characterized by FTIR and NMR spectroscopies,and their properties were determined by gel permeation chromatography,differential scanning calorimetry and thermogravimetric analysis.The obtained results show renewable vegetable oils-based PUs materials can be preparing using a new environmentally ways and giving various good properties performances.展开更多
The first report of new 3-(tetrazol-5-yl)-2-iminocoumarin derivatives is described. The title compounds were prepared in two steps and were obtained in good yields (55-93%). They have been fully characterized by <s...The first report of new 3-(tetrazol-5-yl)-2-iminocoumarin derivatives is described. The title compounds were prepared in two steps and were obtained in good yields (55-93%). They have been fully characterized by <sup>1</sup>H, <sup>13</sup>C NMR, FTIR, UV-Visible and HRMS. They were tested for their antiproliferative activities against six representative human tumor cell lines (Huh 7-D12, Caco2, MDA-MB231, HCT 116, PC3 and NCI-H727) and HaCat keratinocytes. Among them, compound 5e was active on HCT 116 (IC<sub>50</sub> 15 μM).展开更多
The synthesis of 2-phenylimino-4<em>H</em>-chromene-3-carbonitriles <strong>6(a-d)</strong> in good overall yields using an efficient and practical methodology in 3 steps has been implemented i...The synthesis of 2-phenylimino-4<em>H</em>-chromene-3-carbonitriles <strong>6(a-d)</strong> in good overall yields using an efficient and practical methodology in 3 steps has been implemented in this present work. The first step was a heterocyclization between 2-hydroxybenzaldehyde <strong>1</strong> and propanedinitrile <strong>2</strong> which produced 2-iminocoumarin <strong>3</strong> which was submitted to nitrogen/nitrogen displacement in the presence of aromatic primary amine <strong>4</strong>. In the third step, reduction of <strong>5</strong> led to the desired 2-phenylimino-4<em>H</em>-chromene-3-carbonitriles <strong>6</strong>. Compounds <strong>5(a-d)</strong> and <strong>6(a-d)</strong> were evaluated for their potential <em>in vitro</em> cytotoxicity against six selected tumor cell lines (Huh7-D12, Caco2, MDA-MB231, HCT 116, PC3 and NCI-H727) and tested for their protein kinase inhibition on eight selected protein kinases. Among them, compounds <strong>5c</strong> and <strong>6b</strong> exhibited inhibition on HsCK1e (<strong>5c</strong>: 44% and <strong>6b</strong>: 42% at 1 μM) and <strong>5c </strong>for cytotoxicity on PC3 cell lines (63% at 25 μM).展开更多
Eight new compounds containing in their structures substituted quinoline and pyrazole entity were synthesized in good to excellent yield by cyclocondensation reaction of chalcones and hydrazine hydrate. This reaction ...Eight new compounds containing in their structures substituted quinoline and pyrazole entity were synthesized in good to excellent yield by cyclocondensation reaction of chalcones and hydrazine hydrate. This reaction was conducted in formic acid in presence of BF3·Et2O or in acetic acid. These approaches were extended to bis-chalcones, which delivered functionalized bispyrazolines. The structures of the prepared compounds were confirmed by IR, 1HNMR, 13CNMR and mass spectral analysis.展开更多
The catalytic dehydrocyclization of n-hexane was studied here for the first time using a number of compounds based on H3PMo12O40. The described catalysts were prepared by either replacing the acidic proton with counte...The catalytic dehydrocyclization of n-hexane was studied here for the first time using a number of compounds based on H3PMo12O40. The described catalysts were prepared by either replacing the acidic proton with counter-ions such as ammonium or transition metal cations (NH4+, Fe3+, K+), or by replacing Mo6+ with (Ni3+, Co3+, Mn3+) in the polyoxometalate framework, as reported earlier. For comparison purposes, the known (TBA)7PW11O39 catalyst system was used. All reactions were conducted at different temperatures in the range 200 - 450. The Keggin structure of these heteropolycompounds was ascertained by XRD, UV and IR measurements. 31P NMR measurements and thermal behaviour of the prepared catalysts were also studied. These modified polyoxometalates exhibited heterogeneous superacidic catalytic activities in dehydrocyclization of n-hexane into benzene, cyclohexane, cyclohexene and cyclohexadiene. The catalysts obtained by substituting the acidic proton or coordination atom exhibited higher selectivity and stability than the parent compound H3PMo12O40. Catalytic activity and selectivity were heavily dependent on the composition of the catalyst and on the reaction conditions. At higher temperatures, the catalyst exhibited higher conversion efficiency at the expense of selectivity. Using higher temperatures (>400) in the presence of hydrogen carrier gas, selectivity towards dehydrocyclization ceased and methane dominated. To explain the results, a plausible mechanism is presented, based on super-acidic nature of the catalyst systems.展开更多
This study aims to prepare and develop several vehicles chelation polydentate supported ligands and then installed it using sol-gel or polymerization or to be susceptible to imply conjunction with the highly toxic hea...This study aims to prepare and develop several vehicles chelation polydentate supported ligands and then installed it using sol-gel or polymerization or to be susceptible to imply conjunction with the highly toxic heavy metal ions in the water, and disrupted the underground water used for drinking or agriculture, including cadmium ions. As the process of interaction between ligands and heavy metals depends on the circumstances of surrounding conditions which are treated in this research. Metal ion uptake through complexation or hydrogels can be affected by hydrophilic-hydrophobic balance, the nature of chelate ligands and the extent of cross-linking of macromolecular supports. Ligand function also dictates reactivity, complexation ability and efficiency of polymer supported ligands in the present case expected to be good solution for such problem. This research involves the synthesis and characterization of new polysiloxane surfaces modified with ortho-, meta-, or para-nitrophenyl moieties. The resulting adsorbents have been characterized by SEM, IR, UV, <sup>13</sup>C solid state NMR, BET surface area, B.J.H. pore sizes, TGA and nitrogen adsorption-desorption isotherm. These porous materials showed a very good thermal and chemical stability and hence they can be used as perfect adsorbents to uptake toxic heavy metal ions including Cd(II) from groundwater. The concentrations of each adsorbate in the filtrate were determined using Atomic Absorption Spectrophotometer. The results showed that all of the three resulting products had high adsorption efficiency. Also, it showed strong complexation properties with heavy metal ions.展开更多
The rapid diffusion of renewable energy boosts the wide deployment of large-scale energy storage system.With the low cost and high crustal abundance,sodium-ion battery(SIB)technology is expected to become a dominant t...The rapid diffusion of renewable energy boosts the wide deployment of large-scale energy storage system.With the low cost and high crustal abundance,sodium-ion battery(SIB)technology is expected to become a dominant technology in that area in the future.Toward the practical application,novel cathode materials are urged to develop that show high energy density without sacrificing their cost and benignity to the environment.While the years of many studies,this still remains a huge challenge to battery scientists.In this review,we discuss recent breakthroughs in SIB cathode materials with high energy density,namely fluorphosphates and fluorosulfates.The design of materials,the crystal structure,the electrochemical performance,and the underlaying intercalation mechanism are systematically reviewed.Useful strategies and research directions are also provided to advance future high-energy,low-cost,and ecofriendly cathode materials for next generation SIB.展开更多
The inhibition of steel corrosion in hydrochloric acid solutions by limonene, which was extracted from citrus and orange fruit, was studied using measurements of mass loss, electrochemical polarisation and electrochem...The inhibition of steel corrosion in hydrochloric acid solutions by limonene, which was extracted from citrus and orange fruit, was studied using measurements of mass loss, electrochemical polarisation and electrochemical impedance spectroscopy (EIS) methods. Naturally, the substance reduced the rate of corrosion. The linearity of the cathodic curves for all concentrations indicated that the law of Tafel was followed. The effectiveness of inhibition increased with the increase in concentration of limonene and this exceeded 72% at 0.220 g·L-1. The inhibition efficiency is temperature independent in the temperature range of 298-328 K. Adsorption of the substance on the surface of steel obeys the Frumkin isotherm model.展开更多
Polycrystalline of[(Na_(0.535)K_(0.480))_(0.966)Li_(0.058)](Nb_(0.90)Ta_(0.10))O_(3)samples were prepared using the high-temperature solid-state reaction technique.X-ray diffraction(XRD)analysis indicates the formatio...Polycrystalline of[(Na_(0.535)K_(0.480))_(0.966)Li_(0.058)](Nb_(0.90)Ta_(0.10))O_(3)samples were prepared using the high-temperature solid-state reaction technique.X-ray diffraction(XRD)analysis indicates the formation of a single-phase with orthorhombic structure.AC impedance plots were used as tool to analyze the electrical behavior of the sample as a function of frequency at different temperatures.The AC impedance studies revealed the presence of grain effect,from 425℃onwards.Complex impedance analysis indicated non-Debye type dielectric relaxation.The Nyquist plot showed the negative temperature coefficient of resistance(NTCR)characteristic of NKLNT.The AC conductivity results were used to correlate with the barrier hopping(CBH)model to evaluate the binding energy(W_(m)),the minimum hopping distance(R_(min)),the density of states at Fermi level(N(E_(f))),and the activation energy of the compound.展开更多
(Bi_(0.5)Na_(0.5))_(0.94)Ba_(0.06)TiO_(3)+x%Ce_(2)O_(3)+y%La_(2)O_(3)+z%Y_(2)O_(3) compounds(named BNT-BT-x/y/z)were synthesized by a sol-gel technique,for (x,y,z)=(0,0,0),(0.25,0.25,0.25),(0.25,0.5,0.5),(0.5,0.25,0.2...(Bi_(0.5)Na_(0.5))_(0.94)Ba_(0.06)TiO_(3)+x%Ce_(2)O_(3)+y%La_(2)O_(3)+z%Y_(2)O_(3) compounds(named BNT-BT-x/y/z)were synthesized by a sol-gel technique,for (x,y,z)=(0,0,0),(0.25,0.25,0.25),(0.25,0.5,0.5),(0.5,0.25,0.25)and(0.5,0.5,0.25).The structural variation according to the different system compositions is investigated by X-ray diffraction analyses.The results shows that the addition of Ce_(2)O_(3),La_(2)O_(3) or Y_(2)O_(3) in BNT-BT system,do not modify the crystalline structure,and a rhombohedral-tetragonal morphotropic phase boundary is maintained for different dopant addition.The BNT-BT-x/y/z-based ceramics sintered at relatively low temperature(1100℃)exhibit a good densification ratio.The optimum dielectric and piezoelectric properties are obtained with the BNT-BT-0.5/0.25/0.25 composition.High dielectric properties at room temperature(ε_(r)>1000)and low dielectric losses(tanδ<4×10^(-2))are obtained for this composition.This compound exhibits a piezoelectric constant d_(33) of 95 pC/N,a good polarization behavior is observed with high remanent polarization P_(r) of 9.21μC/cm^(2) and low value coercitivefield E_(c) of 2.66 kV/mm.展开更多
基金the“CMPTM Project 17TM22”and to the“PHC-UTIQUE CMCU”(18G1132)the Tunisian Ministry of Higher Education and LabEx Tec 21 for the financial support.
文摘Bio-based polyurethanes(PUs)have been occurred a large attention nowadays.It was found to be an alternative to the petrochemical based materials to the fact of their weak environmental influence,availability,good price and biodegradability.In addition,the nature shows several bio-derived compounds as raw materials for the synthesis of polyols,including the vegetable oils,polyphenol,terpene,and other bio-renewable sources.With the aim to develop a new family of biobased polyurethanes(PUs)via vegetable oils,the elaboration of new Jojoba-based PUs was performed by catalyst-free polycondensation reaction of a synthesized Jojoba diol with various diisocyanates such us toluene diisocyanate(TDI)and isophorone diisocyanate(IPDI).All the compounds were characterized by FTIR and NMR spectroscopies,and their properties were determined by gel permeation chromatography,differential scanning calorimetry and thermogravimetric analysis.The obtained results show renewable vegetable oils-based PUs materials can be preparing using a new environmentally ways and giving various good properties performances.
文摘The first report of new 3-(tetrazol-5-yl)-2-iminocoumarin derivatives is described. The title compounds were prepared in two steps and were obtained in good yields (55-93%). They have been fully characterized by <sup>1</sup>H, <sup>13</sup>C NMR, FTIR, UV-Visible and HRMS. They were tested for their antiproliferative activities against six representative human tumor cell lines (Huh 7-D12, Caco2, MDA-MB231, HCT 116, PC3 and NCI-H727) and HaCat keratinocytes. Among them, compound 5e was active on HCT 116 (IC<sub>50</sub> 15 μM).
文摘The synthesis of 2-phenylimino-4<em>H</em>-chromene-3-carbonitriles <strong>6(a-d)</strong> in good overall yields using an efficient and practical methodology in 3 steps has been implemented in this present work. The first step was a heterocyclization between 2-hydroxybenzaldehyde <strong>1</strong> and propanedinitrile <strong>2</strong> which produced 2-iminocoumarin <strong>3</strong> which was submitted to nitrogen/nitrogen displacement in the presence of aromatic primary amine <strong>4</strong>. In the third step, reduction of <strong>5</strong> led to the desired 2-phenylimino-4<em>H</em>-chromene-3-carbonitriles <strong>6</strong>. Compounds <strong>5(a-d)</strong> and <strong>6(a-d)</strong> were evaluated for their potential <em>in vitro</em> cytotoxicity against six selected tumor cell lines (Huh7-D12, Caco2, MDA-MB231, HCT 116, PC3 and NCI-H727) and tested for their protein kinase inhibition on eight selected protein kinases. Among them, compounds <strong>5c</strong> and <strong>6b</strong> exhibited inhibition on HsCK1e (<strong>5c</strong>: 44% and <strong>6b</strong>: 42% at 1 μM) and <strong>5c </strong>for cytotoxicity on PC3 cell lines (63% at 25 μM).
文摘Eight new compounds containing in their structures substituted quinoline and pyrazole entity were synthesized in good to excellent yield by cyclocondensation reaction of chalcones and hydrazine hydrate. This reaction was conducted in formic acid in presence of BF3·Et2O or in acetic acid. These approaches were extended to bis-chalcones, which delivered functionalized bispyrazolines. The structures of the prepared compounds were confirmed by IR, 1HNMR, 13CNMR and mass spectral analysis.
文摘The catalytic dehydrocyclization of n-hexane was studied here for the first time using a number of compounds based on H3PMo12O40. The described catalysts were prepared by either replacing the acidic proton with counter-ions such as ammonium or transition metal cations (NH4+, Fe3+, K+), or by replacing Mo6+ with (Ni3+, Co3+, Mn3+) in the polyoxometalate framework, as reported earlier. For comparison purposes, the known (TBA)7PW11O39 catalyst system was used. All reactions were conducted at different temperatures in the range 200 - 450. The Keggin structure of these heteropolycompounds was ascertained by XRD, UV and IR measurements. 31P NMR measurements and thermal behaviour of the prepared catalysts were also studied. These modified polyoxometalates exhibited heterogeneous superacidic catalytic activities in dehydrocyclization of n-hexane into benzene, cyclohexane, cyclohexene and cyclohexadiene. The catalysts obtained by substituting the acidic proton or coordination atom exhibited higher selectivity and stability than the parent compound H3PMo12O40. Catalytic activity and selectivity were heavily dependent on the composition of the catalyst and on the reaction conditions. At higher temperatures, the catalyst exhibited higher conversion efficiency at the expense of selectivity. Using higher temperatures (>400) in the presence of hydrogen carrier gas, selectivity towards dehydrocyclization ceased and methane dominated. To explain the results, a plausible mechanism is presented, based on super-acidic nature of the catalyst systems.
文摘This study aims to prepare and develop several vehicles chelation polydentate supported ligands and then installed it using sol-gel or polymerization or to be susceptible to imply conjunction with the highly toxic heavy metal ions in the water, and disrupted the underground water used for drinking or agriculture, including cadmium ions. As the process of interaction between ligands and heavy metals depends on the circumstances of surrounding conditions which are treated in this research. Metal ion uptake through complexation or hydrogels can be affected by hydrophilic-hydrophobic balance, the nature of chelate ligands and the extent of cross-linking of macromolecular supports. Ligand function also dictates reactivity, complexation ability and efficiency of polymer supported ligands in the present case expected to be good solution for such problem. This research involves the synthesis and characterization of new polysiloxane surfaces modified with ortho-, meta-, or para-nitrophenyl moieties. The resulting adsorbents have been characterized by SEM, IR, UV, <sup>13</sup>C solid state NMR, BET surface area, B.J.H. pore sizes, TGA and nitrogen adsorption-desorption isotherm. These porous materials showed a very good thermal and chemical stability and hence they can be used as perfect adsorbents to uptake toxic heavy metal ions including Cd(II) from groundwater. The concentrations of each adsorbate in the filtrate were determined using Atomic Absorption Spectrophotometer. The results showed that all of the three resulting products had high adsorption efficiency. Also, it showed strong complexation properties with heavy metal ions.
基金supported by the National Natural Science Foundation of China(No.22179098).
文摘The rapid diffusion of renewable energy boosts the wide deployment of large-scale energy storage system.With the low cost and high crustal abundance,sodium-ion battery(SIB)technology is expected to become a dominant technology in that area in the future.Toward the practical application,novel cathode materials are urged to develop that show high energy density without sacrificing their cost and benignity to the environment.While the years of many studies,this still remains a huge challenge to battery scientists.In this review,we discuss recent breakthroughs in SIB cathode materials with high energy density,namely fluorphosphates and fluorosulfates.The design of materials,the crystal structure,the electrochemical performance,and the underlaying intercalation mechanism are systematically reviewed.Useful strategies and research directions are also provided to advance future high-energy,low-cost,and ecofriendly cathode materials for next generation SIB.
文摘The inhibition of steel corrosion in hydrochloric acid solutions by limonene, which was extracted from citrus and orange fruit, was studied using measurements of mass loss, electrochemical polarisation and electrochemical impedance spectroscopy (EIS) methods. Naturally, the substance reduced the rate of corrosion. The linearity of the cathodic curves for all concentrations indicated that the law of Tafel was followed. The effectiveness of inhibition increased with the increase in concentration of limonene and this exceeded 72% at 0.220 g·L-1. The inhibition efficiency is temperature independent in the temperature range of 298-328 K. Adsorption of the substance on the surface of steel obeys the Frumkin isotherm model.
文摘Polycrystalline of[(Na_(0.535)K_(0.480))_(0.966)Li_(0.058)](Nb_(0.90)Ta_(0.10))O_(3)samples were prepared using the high-temperature solid-state reaction technique.X-ray diffraction(XRD)analysis indicates the formation of a single-phase with orthorhombic structure.AC impedance plots were used as tool to analyze the electrical behavior of the sample as a function of frequency at different temperatures.The AC impedance studies revealed the presence of grain effect,from 425℃onwards.Complex impedance analysis indicated non-Debye type dielectric relaxation.The Nyquist plot showed the negative temperature coefficient of resistance(NTCR)characteristic of NKLNT.The AC conductivity results were used to correlate with the barrier hopping(CBH)model to evaluate the binding energy(W_(m)),the minimum hopping distance(R_(min)),the density of states at Fermi level(N(E_(f))),and the activation energy of the compound.
文摘(Bi_(0.5)Na_(0.5))_(0.94)Ba_(0.06)TiO_(3)+x%Ce_(2)O_(3)+y%La_(2)O_(3)+z%Y_(2)O_(3) compounds(named BNT-BT-x/y/z)were synthesized by a sol-gel technique,for (x,y,z)=(0,0,0),(0.25,0.25,0.25),(0.25,0.5,0.5),(0.5,0.25,0.25)and(0.5,0.5,0.25).The structural variation according to the different system compositions is investigated by X-ray diffraction analyses.The results shows that the addition of Ce_(2)O_(3),La_(2)O_(3) or Y_(2)O_(3) in BNT-BT system,do not modify the crystalline structure,and a rhombohedral-tetragonal morphotropic phase boundary is maintained for different dopant addition.The BNT-BT-x/y/z-based ceramics sintered at relatively low temperature(1100℃)exhibit a good densification ratio.The optimum dielectric and piezoelectric properties are obtained with the BNT-BT-0.5/0.25/0.25 composition.High dielectric properties at room temperature(ε_(r)>1000)and low dielectric losses(tanδ<4×10^(-2))are obtained for this composition.This compound exhibits a piezoelectric constant d_(33) of 95 pC/N,a good polarization behavior is observed with high remanent polarization P_(r) of 9.21μC/cm^(2) and low value coercitivefield E_(c) of 2.66 kV/mm.