Photocatalytic oxidation kinetics of thiophene in n-octane/water extraction system was studied with fluorine and ferric ion codoped nano-TiO<sub>2</sub>(nano-F<sup>-</sup>/Fe<sup>3+</s...Photocatalytic oxidation kinetics of thiophene in n-octane/water extraction system was studied with fluorine and ferric ion codoped nano-TiO<sub>2</sub>(nano-F<sup>-</sup>/Fe<sup>3+</sup>/TiO<sub>2</sub>) powders used as the photocatalyst.Effects of initial concentration of thiophene and additional dosage of F<sup>-</sup>/Fe<sup>3+</sup>/TiO<sub>2</sub> on the reaction rate constant and half-life were investigated.The results showed that the appropriately added dosage of F<sup>-</sup>/Fe<sup>3+</sup>/TiO<sub>2</sub> was 0.1 g in the 100-mL reaction system and the photooxidative kinetics of thiophene in the presence of F<sup>-</sup>/Fe<sup>3+</sup>/TiO<sub>2</sub> catalyst was of first-order with a rate constant of 0.6508 h<sup>-1</sup> and a half-life of 1.0651 h.The desulfurization rate of thiophene was 98.1%in 5 h and the sulfur content could be reduced from 800 ppm to 15 ppm.The reaction rate constant increased with a decreasing initial concentration of thiophene.展开更多
Thiophene C4H4S and 3-methylthiophene3-MC4H4S are typical thiophenenic sulfur compounds that exist in fluid catalytic cracking FCC gasoline. Oxidation of C4H4S and 3-MC4H4S were conducted in hydrogen peroxide H2O2 and...Thiophene C4H4S and 3-methylthiophene3-MC4H4S are typical thiophenenic sulfur compounds that exist in fluid catalytic cracking FCC gasoline. Oxidation of C4H4S and 3-MC4H4S were conducted in hydrogen peroxide H2O2 and formic acid system over a series of silica gel loaded with metal oxide. The silica gel loaded with copper and cobalt 1:1 oxide was found very active for the model compound oxidation using H2O2formic acid, while the silica gel unloaded with metal oxide was less active. The sulfur removal rate of thiophenes was dif- ferent as solvent was changed. And the conversation of C4H4S and 3-MC4H4S was improved at higher temperature, but reduced when olefin was added. The sulfur removal rate of model sulfur compounds was enhanced when the phase transfer catalyst emulsifier polyethylene glycol octyl phenyl ether or tetrabutylammonium bromideTBAB was added. The sulfur removal rate of simulated gasoline containing 524μg·ml-1 sulfur reached 90%. Interestingly, in a H2O2 and formic acid system with the addition of TBAB, a bromine substitution trend appeared in the oxidation of thiophenes, suggesting the influence of TBAB.展开更多
The title compounds, 2-(3,3'-bithiophen-2,2'-yl)dibenzothiazole (BTDB) and 2-(dithieno[2,3-b:3',2'-d]thiophen-2,5-yl)dibenzothiazole (DTTDB), have been synthesized and characterized by FT-IR, NMR, MS, HRM...The title compounds, 2-(3,3'-bithiophen-2,2'-yl)dibenzothiazole (BTDB) and 2-(dithieno[2,3-b:3',2'-d]thiophen-2,5-yl)dibenzothiazole (DTTDB), have been synthesized and characterized by FT-IR, NMR, MS, HRMS and X-ray single-crystal diffraction. The crystal of BTDB crystallizes in triclinic, space group P1 with a = 9.2207(17), b = 10.453(2), c = 10.969(2) A, V= 981.2(3) A3 and Z = 2. Crystal data of DTTDB: orthorhombic system, space group Pbcn with a = 4.5290(8), b = 13.576(3), c = 32.033(6) A, V= 1969.6(6) A3 and Z = 4.展开更多
Coumarins occupy an important place in the realm of natural products and synthetic organic chemistry. A fast and highly efficient green method for synthesizing 3-aryl coumarin derivatives from salicylaldehyde and phen...Coumarins occupy an important place in the realm of natural products and synthetic organic chemistry. A fast and highly efficient green method for synthesizing 3-aryl coumarin derivatives from salicylaldehyde and phenyl acetyl chloride in the presence of tetrahydrofuran and K2CO3 using ultrasound irradiation is reported. Ultrasound assisted reactions have resulted in better yields and faster reaction time of the desired products than when prepared under conventional conditions. The resulting coumarin derivatives were characterized by IR spectrum.展开更多
Two alkyl substituted polythiophene derivatives: poly(3-hexylthiophene)(P3HT) and poly(3-decylthiophene)(P3DT), have synthesized by oxidation coupling polymerization of 3-alkylthiophene using iron(III) chloride as cat...Two alkyl substituted polythiophene derivatives: poly(3-hexylthiophene)(P3HT) and poly(3-decylthiophene)(P3DT), have synthesized by oxidation coupling polymerization of 3-alkylthiophene using iron(III) chloride as catalyst in chloroform. While both polymers in pure chloroform solution have maximum absorption at approximately same wavelength of 440nm, they behave differently with respect to changes observed on their UV-visible and photoluminescence spectra when the quality of the poor solvent is changed in good solvent (chloroform) / poor solvent (methanol) mixtures. With increasing volume fraction of methanol in mixtures, the absorption spectra of P3HT and P3DT red-shift, peaking at maximum wavelength of 495nm (P3HT) and 510nm(P3DT). Furthermore, the absorption spectra of the two polymers in chloroform blue-shift as the temperature rises. P3HT shows 4.73nm blue-shifts at 50℃ in contrast to the case at 20℃, while P3DT blue-shifts about 5.04nm. The photoluminescence spectra of the two polymers in mixed solution are also investigated, which show that the luminescence spectra shift to longer wavelength with an accompanying drop in the PL intensity as methanol is increased. The absorption and emission spectra of the two polymers in a poor solvent and a thin film are similar, which indicate that a similar longer conjugation length in the two cases. It could conclude that the polymers exist almost the same conformations and aggregations in both a poor solvent and a thin film. P3DT exhibits more sensitive spectra properties (big red-shifts in both absorption and luminescence spectra in poor solvents and large blue-shifts at high temperature) with contrast to P3HT, which imply that long side alkyl may improve the chromic properties of the polymer.展开更多
Third-order nonlinear optical (NLO) materials have broad application prospects in high-density data storage, optical computer, modern laser technology, and other high-tech industries. The structures and frequencies of...Third-order nonlinear optical (NLO) materials have broad application prospects in high-density data storage, optical computer, modern laser technology, and other high-tech industries. The structures and frequencies of Dinaphtho[2,3-b:2’,3’-d]thiophene-5,7,12,13-tetraone (DNTTRA) and its 36 derivatives containing azobenzene were calculated by using density functional theory B3LYP and M06-2X methods at 6-311++g(d, p) level, respectively. Besides, the atomic charges of natural bond orbitals (NBO) were analyzed. The frontier orbitals and electron absorption spectra of A-G5 molecule were calculated by TD-DFT (TD-B3LYP/6-311++g(d, p) and TD-M06-2X/6-311++g(d, p)). The NLO properties were calculated by effective finite field FF method and self-compiled program. The results show that 36 molecules of these six series are D-π-A-π-D structures. The third-order NLO coefficients γ (second-order hyperpolarizability) of the D series molecules are the largest among the six series, reaching 10<sup>7</sup> atomic units (10<sup><span style="color:#4F4F4F;font-family:-apple-system, " font-size:14px;white-space:normal;background-color:#ffffff;"="">-</span>33</sup> esu) of order of magnitude, showing good third-order NLO properties. Last, the third-order NLO properties of the azobenzene ring can be improved by introducing strong electron donor groups (e.g. -N(CH<sub>3</sub>)<sub>2</sub> or -NHCH<sub>3</sub>) in the azobenzene ring, so that the third-order NLO materials with good performance can be obtained.展开更多
A series of sulfided PtMo/ γ Al 2O 3 catalysts[ w (Mo)=9.0%] with different contents of Pt were characterized by using low temperature FTIR spectroscopy of adsorbed CO, while their HDS activity was investigated with ...A series of sulfided PtMo/ γ Al 2O 3 catalysts[ w (Mo)=9.0%] with different contents of Pt were characterized by using low temperature FTIR spectroscopy of adsorbed CO, while their HDS activity was investigated with thiophene as a model substrate. Experimentally, it was found that no existence of the bands related to the surface complexes of Al 3+ ←CO and Pt 0←CO→Pt 0 was observed at 77 K and that the rate of the thiophene HDS reaction(573 K) is well linearly proportional to the area of the Pt 0←CO band at 2 093 cm -1 with a higher extrapolated HDS rate compared to that of sulfided Mo/ γ Al 2O 3 catalyst at the zero content of platinum. On the basis of the results here, the conclusion may be made that the active monolayer phase of Pt Mo S may be formed over sulfided PtMo/ γ Al 2O 3 catalysts during the sulfidation process and that both Mo 2+ and Pt 0 sites for CO adsorption should be the active reaction centers of thiophene HDS.展开更多
基金support from the Natural Science Foundation of Gansu Province(No.3ZS061- A25-019)the Scientific Research fund of Gansu Provincial Education Department(No.0601-25)
文摘Photocatalytic oxidation kinetics of thiophene in n-octane/water extraction system was studied with fluorine and ferric ion codoped nano-TiO<sub>2</sub>(nano-F<sup>-</sup>/Fe<sup>3+</sup>/TiO<sub>2</sub>) powders used as the photocatalyst.Effects of initial concentration of thiophene and additional dosage of F<sup>-</sup>/Fe<sup>3+</sup>/TiO<sub>2</sub> on the reaction rate constant and half-life were investigated.The results showed that the appropriately added dosage of F<sup>-</sup>/Fe<sup>3+</sup>/TiO<sub>2</sub> was 0.1 g in the 100-mL reaction system and the photooxidative kinetics of thiophene in the presence of F<sup>-</sup>/Fe<sup>3+</sup>/TiO<sub>2</sub> catalyst was of first-order with a rate constant of 0.6508 h<sup>-1</sup> and a half-life of 1.0651 h.The desulfurization rate of thiophene was 98.1%in 5 h and the sulfur content could be reduced from 800 ppm to 15 ppm.The reaction rate constant increased with a decreasing initial concentration of thiophene.
基金the National Natural Science Foundation of China (No.20276015) the Natural Science Foundation of HebeiProvince (No.203364)
文摘Thiophene C4H4S and 3-methylthiophene3-MC4H4S are typical thiophenenic sulfur compounds that exist in fluid catalytic cracking FCC gasoline. Oxidation of C4H4S and 3-MC4H4S were conducted in hydrogen peroxide H2O2 and formic acid system over a series of silica gel loaded with metal oxide. The silica gel loaded with copper and cobalt 1:1 oxide was found very active for the model compound oxidation using H2O2formic acid, while the silica gel unloaded with metal oxide was less active. The sulfur removal rate of thiophenes was dif- ferent as solvent was changed. And the conversation of C4H4S and 3-MC4H4S was improved at higher temperature, but reduced when olefin was added. The sulfur removal rate of model sulfur compounds was enhanced when the phase transfer catalyst emulsifier polyethylene glycol octyl phenyl ether or tetrabutylammonium bromideTBAB was added. The sulfur removal rate of simulated gasoline containing 524μg·ml-1 sulfur reached 90%. Interestingly, in a H2O2 and formic acid system with the addition of TBAB, a bromine substitution trend appeared in the oxidation of thiophenes, suggesting the influence of TBAB.
基金supported by the National Natural Science Foundation of China (20972041)Program for Innovation Scientists and Technicians Troop Construction Projects of Henan Province (104100510011)the Program of Henan University (SBGJ090506)
文摘The title compounds, 2-(3,3'-bithiophen-2,2'-yl)dibenzothiazole (BTDB) and 2-(dithieno[2,3-b:3',2'-d]thiophen-2,5-yl)dibenzothiazole (DTTDB), have been synthesized and characterized by FT-IR, NMR, MS, HRMS and X-ray single-crystal diffraction. The crystal of BTDB crystallizes in triclinic, space group P1 with a = 9.2207(17), b = 10.453(2), c = 10.969(2) A, V= 981.2(3) A3 and Z = 2. Crystal data of DTTDB: orthorhombic system, space group Pbcn with a = 4.5290(8), b = 13.576(3), c = 32.033(6) A, V= 1969.6(6) A3 and Z = 4.
文摘Coumarins occupy an important place in the realm of natural products and synthetic organic chemistry. A fast and highly efficient green method for synthesizing 3-aryl coumarin derivatives from salicylaldehyde and phenyl acetyl chloride in the presence of tetrahydrofuran and K2CO3 using ultrasound irradiation is reported. Ultrasound assisted reactions have resulted in better yields and faster reaction time of the desired products than when prepared under conventional conditions. The resulting coumarin derivatives were characterized by IR spectrum.
基金National Natural Science Foundation of China (60277002)
文摘Two alkyl substituted polythiophene derivatives: poly(3-hexylthiophene)(P3HT) and poly(3-decylthiophene)(P3DT), have synthesized by oxidation coupling polymerization of 3-alkylthiophene using iron(III) chloride as catalyst in chloroform. While both polymers in pure chloroform solution have maximum absorption at approximately same wavelength of 440nm, they behave differently with respect to changes observed on their UV-visible and photoluminescence spectra when the quality of the poor solvent is changed in good solvent (chloroform) / poor solvent (methanol) mixtures. With increasing volume fraction of methanol in mixtures, the absorption spectra of P3HT and P3DT red-shift, peaking at maximum wavelength of 495nm (P3HT) and 510nm(P3DT). Furthermore, the absorption spectra of the two polymers in chloroform blue-shift as the temperature rises. P3HT shows 4.73nm blue-shifts at 50℃ in contrast to the case at 20℃, while P3DT blue-shifts about 5.04nm. The photoluminescence spectra of the two polymers in mixed solution are also investigated, which show that the luminescence spectra shift to longer wavelength with an accompanying drop in the PL intensity as methanol is increased. The absorption and emission spectra of the two polymers in a poor solvent and a thin film are similar, which indicate that a similar longer conjugation length in the two cases. It could conclude that the polymers exist almost the same conformations and aggregations in both a poor solvent and a thin film. P3DT exhibits more sensitive spectra properties (big red-shifts in both absorption and luminescence spectra in poor solvents and large blue-shifts at high temperature) with contrast to P3HT, which imply that long side alkyl may improve the chromic properties of the polymer.
文摘Third-order nonlinear optical (NLO) materials have broad application prospects in high-density data storage, optical computer, modern laser technology, and other high-tech industries. The structures and frequencies of Dinaphtho[2,3-b:2’,3’-d]thiophene-5,7,12,13-tetraone (DNTTRA) and its 36 derivatives containing azobenzene were calculated by using density functional theory B3LYP and M06-2X methods at 6-311++g(d, p) level, respectively. Besides, the atomic charges of natural bond orbitals (NBO) were analyzed. The frontier orbitals and electron absorption spectra of A-G5 molecule were calculated by TD-DFT (TD-B3LYP/6-311++g(d, p) and TD-M06-2X/6-311++g(d, p)). The NLO properties were calculated by effective finite field FF method and self-compiled program. The results show that 36 molecules of these six series are D-π-A-π-D structures. The third-order NLO coefficients γ (second-order hyperpolarizability) of the D series molecules are the largest among the six series, reaching 10<sup>7</sup> atomic units (10<sup><span style="color:#4F4F4F;font-family:-apple-system, " font-size:14px;white-space:normal;background-color:#ffffff;"="">-</span>33</sup> esu) of order of magnitude, showing good third-order NLO properties. Last, the third-order NLO properties of the azobenzene ring can be improved by introducing strong electron donor groups (e.g. -N(CH<sub>3</sub>)<sub>2</sub> or -NHCH<sub>3</sub>) in the azobenzene ring, so that the third-order NLO materials with good performance can be obtained.
文摘A series of sulfided PtMo/ γ Al 2O 3 catalysts[ w (Mo)=9.0%] with different contents of Pt were characterized by using low temperature FTIR spectroscopy of adsorbed CO, while their HDS activity was investigated with thiophene as a model substrate. Experimentally, it was found that no existence of the bands related to the surface complexes of Al 3+ ←CO and Pt 0←CO→Pt 0 was observed at 77 K and that the rate of the thiophene HDS reaction(573 K) is well linearly proportional to the area of the Pt 0←CO band at 2 093 cm -1 with a higher extrapolated HDS rate compared to that of sulfided Mo/ γ Al 2O 3 catalyst at the zero content of platinum. On the basis of the results here, the conclusion may be made that the active monolayer phase of Pt Mo S may be formed over sulfided PtMo/ γ Al 2O 3 catalysts during the sulfidation process and that both Mo 2+ and Pt 0 sites for CO adsorption should be the active reaction centers of thiophene HDS.