Esterification of aromatic acid can be promoted via HSO3-functionalized Br nsted acidic ionic liquids (ILs). Under the optimum conditions, using 1-(3-sulfonic acid) propyl-3-methylimidazolium hydrogen sulfate ([MimC3S...Esterification of aromatic acid can be promoted via HSO3-functionalized Br nsted acidic ionic liquids (ILs). Under the optimum conditions, using 1-(3-sulfonic acid) propyl-3-methylimidazolium hydrogen sulfate ([MimC3SO3H][HSO4]) and 1-(4-sulfonic acid) butyl-3-methylimidazolium hydrogen sulfate ([MimC 4 SO 3 H][HSO4 ]) as dual solvent-catalysts, the conversion of esterification of aromatic acid was determined to be more than 90%, indicating that HSO3-functionalized ILs show much better catalytic ability than those of non-functionalized ionic liquids. The separation of desired product was easily performed by extraction with diethyl ether and these HSO3-functionalized ILs could be reused 7 times after vacuum drying. Our data represent an environmentally friendly method for the preparation of aromatic esters.展开更多
Novel dual-responsive superhydrophobic hybrid materials,ZnO/SAMs(self-assembled monolayers)of ionic liquids(ILs)with different counter-anions(I-,BF4-,PF6-and Tf2N-),were synthesized and characterized.ZnO nanoparticles...Novel dual-responsive superhydrophobic hybrid materials,ZnO/SAMs(self-assembled monolayers)of ionic liquids(ILs)with different counter-anions(I-,BF4-,PF6-and Tf2N-),were synthesized and characterized.ZnO nanoparticles were first deposited on glass surfaces to produce roughness.Next,SAMs of fluorinated-alkyl-3-(3-triethoxysilylpropyl)-4,5-dihydro-imidazoliumiodide(abb.[C8Ftespim]I)were grafted onto these surfaces via-Si-O-covalent bonds using self-assembly technique.The Iion could be subsequently exchanged with BF4-,PF6-or Tf2N-through a simple aqueous anion-exchange reaction.The ZnO/ILs hybrid layers were characterized by atomic-force microscopy(AFM),scanning-electron microscopy(SEM)and X-ray photoelectron spectroscopy(XPS).Their wettability was estimated through the measurements of static and dynamic contact angles(CAs).Compared to corresponding films of ZnO/[C8Ftespim]I with CAs 140.7°±2.0°,films of ZnO/[C8Ftespim]PF6 and ZnO/[C8Ftespim]Tf2N showed CAs with 154.0°±2.0°and 152.0°±2.0°,respectively that remained for a long time.This result suggests that anion-exchange can afford superhydrophobic materials.In addition,the wettability of ZnO/[C8Ftespim]X hybrid layers can be reversibly switched by altering ultraviolet(UV)irradiation and dark storage,which shows a photo-induced reversible switch of wettability.The synergistic action of ZnO nanoparticles and SAMs of ILs produced light-anion dual-responsive superhydrophobic materials with ideal stability.展开更多
We report layer-by-layer (LbL) assembly of TiO2 and H4 SiW12 O40 (SiW 12 ) multilayer film on silicon wafers and glass slides for photocatalytic degradation of methyl orange (MO). The photocatalytic efficiency of the ...We report layer-by-layer (LbL) assembly of TiO2 and H4 SiW12 O40 (SiW 12 ) multilayer film on silicon wafers and glass slides for photocatalytic degradation of methyl orange (MO). The photocatalytic efficiency of the obtained multilayer film increases along with the decrease of pH and salt concentration of the incubation solution. The results show that MO can be almost removed in pH2.0 solution without salt addition in the first 60 min incubation when MO concentration is lower than 15 mg/L. Different salts show an apparent inhibitory effect on photocatalytic degradation of MO with the order of ZnCl2 >KCl> NaCl>LiCl. The TiO2 /SiW12 multilayer film maintains photocatalytic activity even after five degradation cycles. The reaction of MO photodegradation accords with an apparent first-order dynamics.展开更多
Cationic base surfactant, tetradecyltrimethylammonium hydroxide (TTAOH), can be obtained through anion exchange from tetradecyltrimethylammonium bromide (TTABr). Salt-free cationic and anionic (catanionic) surfactant ...Cationic base surfactant, tetradecyltrimethylammonium hydroxide (TTAOH), can be obtained through anion exchange from tetradecyltrimethylammonium bromide (TTABr). Salt-free cationic and anionic (catanionic) surfactant mixtures were studied by mixing TTAOH with oleic acid (OA) or stearic acid (SA) in water. The phase behavior of TTAOH/OA/H2O is compared with that of TTAOH/SA/H2O. It was found that the phase behavior of TTAOH/OA/H2O and TTAOH/SA/H2O system differs from each other due to the existence of the unsaturated double carbon bond (C=C) in OA. At fixed total surfactant concentration (25 mg/mL) of TTAOH/OA/H2O system at 25℃, one can observe an isotropic L1 phase, and a L1/Lα two-phase region with increasing OA content. The volume of top turbid Lα phase increases while the bottom phase changes gradually from transparently clear to a bit turbid until a single Lα-phase is reached. Finally at high OA concentration, excess OA is separated from the bulk aqueous solutions. TTAOH/SA/H2O system usually forms white precipitating at 25℃ due to the high chain melting temperature of SA. When heated to 60℃, however, the state of samples changes. At fixed total surfactant concentration of 25 mg/mL, an isotropic L1 phase and a milk-white or bluish Lα-phase are observed with increasing SA concentration. Transparent thin layers which are strongly birefringent form at the tops of some samples within the Lα-phase region. Finally, at high SA concentration, excess SA is separated from the bulk aqueous solutions. In addition to phase behavior study, we also measured the conductivity of TTAOH/OA/H2O system at 25℃ and TTAOH/SA/H2O system at 60℃, respectively. Surface tension and rheological measurements were also performed on typical samples.展开更多
基金supported by the Natural Science Foundation of Shandong Province (ZR2010BL005)Shandong Provincial Science and Technology Research Projects (2011GSF11818 and 2011YD02082)
文摘Esterification of aromatic acid can be promoted via HSO3-functionalized Br nsted acidic ionic liquids (ILs). Under the optimum conditions, using 1-(3-sulfonic acid) propyl-3-methylimidazolium hydrogen sulfate ([MimC3SO3H][HSO4]) and 1-(4-sulfonic acid) butyl-3-methylimidazolium hydrogen sulfate ([MimC 4 SO 3 H][HSO4 ]) as dual solvent-catalysts, the conversion of esterification of aromatic acid was determined to be more than 90%, indicating that HSO3-functionalized ILs show much better catalytic ability than those of non-functionalized ionic liquids. The separation of desired product was easily performed by extraction with diethyl ether and these HSO3-functionalized ILs could be reused 7 times after vacuum drying. Our data represent an environmentally friendly method for the preparation of aromatic esters.
基金financially supported by the National Natural Science Foundation of China(21033005,21273134)the National Basic Research Program of China(2009CB930103)+2 种基金the Natural Science Foundation of Shandong Province(Combination Research Projects,ZR2013EML003&ZR2013BL001)National Undergraduate Training Programs for Innovation and Entrepreneurship(201310448008)Research Projects of Solar Energy of Dezhou University(311416&SYJS-B13003)
文摘Novel dual-responsive superhydrophobic hybrid materials,ZnO/SAMs(self-assembled monolayers)of ionic liquids(ILs)with different counter-anions(I-,BF4-,PF6-and Tf2N-),were synthesized and characterized.ZnO nanoparticles were first deposited on glass surfaces to produce roughness.Next,SAMs of fluorinated-alkyl-3-(3-triethoxysilylpropyl)-4,5-dihydro-imidazoliumiodide(abb.[C8Ftespim]I)were grafted onto these surfaces via-Si-O-covalent bonds using self-assembly technique.The Iion could be subsequently exchanged with BF4-,PF6-or Tf2N-through a simple aqueous anion-exchange reaction.The ZnO/ILs hybrid layers were characterized by atomic-force microscopy(AFM),scanning-electron microscopy(SEM)and X-ray photoelectron spectroscopy(XPS).Their wettability was estimated through the measurements of static and dynamic contact angles(CAs).Compared to corresponding films of ZnO/[C8Ftespim]I with CAs 140.7°±2.0°,films of ZnO/[C8Ftespim]PF6 and ZnO/[C8Ftespim]Tf2N showed CAs with 154.0°±2.0°and 152.0°±2.0°,respectively that remained for a long time.This result suggests that anion-exchange can afford superhydrophobic materials.In addition,the wettability of ZnO/[C8Ftespim]X hybrid layers can be reversibly switched by altering ultraviolet(UV)irradiation and dark storage,which shows a photo-induced reversible switch of wettability.The synergistic action of ZnO nanoparticles and SAMs of ILs produced light-anion dual-responsive superhydrophobic materials with ideal stability.
基金financially supported by the National Natural Science Foundation of China (21033005)the National Basic Research Program of China (973 Program, 2009CB930103)Natural Science Foundation of Shandong Province (2009ZRB01876)
文摘We report layer-by-layer (LbL) assembly of TiO2 and H4 SiW12 O40 (SiW 12 ) multilayer film on silicon wafers and glass slides for photocatalytic degradation of methyl orange (MO). The photocatalytic efficiency of the obtained multilayer film increases along with the decrease of pH and salt concentration of the incubation solution. The results show that MO can be almost removed in pH2.0 solution without salt addition in the first 60 min incubation when MO concentration is lower than 15 mg/L. Different salts show an apparent inhibitory effect on photocatalytic degradation of MO with the order of ZnCl2 >KCl> NaCl>LiCl. The TiO2 /SiW12 multilayer film maintains photocatalytic activity even after five degradation cycles. The reaction of MO photodegradation accords with an apparent first-order dynamics.
基金Supported by the National Natural Science Foundation of China (Grant No. 20803045)National Basic Research Program of China) (Grant No. 2009CB 930103)New Teacher’s Foundation of Ministry of Education (Grant No. 200804221008)
文摘Cationic base surfactant, tetradecyltrimethylammonium hydroxide (TTAOH), can be obtained through anion exchange from tetradecyltrimethylammonium bromide (TTABr). Salt-free cationic and anionic (catanionic) surfactant mixtures were studied by mixing TTAOH with oleic acid (OA) or stearic acid (SA) in water. The phase behavior of TTAOH/OA/H2O is compared with that of TTAOH/SA/H2O. It was found that the phase behavior of TTAOH/OA/H2O and TTAOH/SA/H2O system differs from each other due to the existence of the unsaturated double carbon bond (C=C) in OA. At fixed total surfactant concentration (25 mg/mL) of TTAOH/OA/H2O system at 25℃, one can observe an isotropic L1 phase, and a L1/Lα two-phase region with increasing OA content. The volume of top turbid Lα phase increases while the bottom phase changes gradually from transparently clear to a bit turbid until a single Lα-phase is reached. Finally at high OA concentration, excess OA is separated from the bulk aqueous solutions. TTAOH/SA/H2O system usually forms white precipitating at 25℃ due to the high chain melting temperature of SA. When heated to 60℃, however, the state of samples changes. At fixed total surfactant concentration of 25 mg/mL, an isotropic L1 phase and a milk-white or bluish Lα-phase are observed with increasing SA concentration. Transparent thin layers which are strongly birefringent form at the tops of some samples within the Lα-phase region. Finally, at high SA concentration, excess SA is separated from the bulk aqueous solutions. In addition to phase behavior study, we also measured the conductivity of TTAOH/OA/H2O system at 25℃ and TTAOH/SA/H2O system at 60℃, respectively. Surface tension and rheological measurements were also performed on typical samples.
