p-Aminobenzenesulfonic acid was selected as a typical solute withamphoteric functional groups to be separated from dilute solution. Aquaternary ammonium chloride, Aliquat 336, was used as theextractant. The effects of...p-Aminobenzenesulfonic acid was selected as a typical solute withamphoteric functional groups to be separated from dilute solution. Aquaternary ammonium chloride, Aliquat 336, was used as theextractant. The effects of pH, extractant concentration and diluenttypes on distribution coefficient, D, were investigated. Meanwhile,the ion exchange reaction for Aliquat 336 with p-aminobenzenesulfonicacid in the extraction process Was discussed. The description of Dwas proposed according to the mass action law.展开更多
It is of great significance to develop high-temperature anhydrous proton conducting materials.Herein,we report a new strategy to significantly enhance the proton conductivity of covalent organic frameworks(COFs)throug...It is of great significance to develop high-temperature anhydrous proton conducting materials.Herein,we report a new strategy to significantly enhance the proton conductivity of covalent organic frameworks(COFs)through expanding the dimensionality of proton conduction.Three COF-based composites,COF-1@PA,COF-2@PA,and COF-3@PA(PA:phosphoric acid),are prepared by PA doping of three COFs with similar pore sizes but different amounts of hydrophilic groups.With the increase of hydrophilic groups,COFs can load more PA because of the enhanced hydrogen–bonding interactions between PA and the frameworks.powder X-ray diffraction(PXRD),scanning electron microscopy(SEM),and two-dimensional(2D)solid-state nuclear magnetic resonance(NMR)analyses show that PA can not only enter the channels of COF-3,but also insert into its 2D interlayers.This expands the proton conduction pathways from one-dimensional(1D)to three-dimensional(3D),which greatly improves the proton conductivity of COF-3.Meanwhile,the confinement effect of 1D channels and 2D layers of COF-3 also makes the hydrogen-bonded networks more orderly in COF-3@PA-30(30μL of PA loaded on COF-3).At 150℃,COF-3@PA-30 exhibits an ultrahigh anhydrous proton conductivity of 1.4 S·cm−1,which is a record of anhydrous proton conductivity reported to date.This work develops a new strategy for increasing the proton conductivity of 2D COF materials.展开更多
A simultaneous differential scanning calorimetryeFourier transform infrared(DSCeFTIR)microspectroscopy was used to quickly investigate the co-crystal formulation between anhydrous theophylline(TP)and anhydrous citric ...A simultaneous differential scanning calorimetryeFourier transform infrared(DSCeFTIR)microspectroscopy was used to quickly investigate the co-crystal formulation between anhydrous theophylline(TP)and anhydrous citric acid(CA)in a one-step procedure.The raw materials of TP andCA,aswell as the intactTPeCA co-crystal prepared by slow solvent evaporation were also respectively examined by this approach.The result indicates that the TPeCA cocrystal formulation was easily induced using this DSCeFTIR technique.The thermaldependent changes in three-dimensional FTIR spectral contour profiles were started from 165C to induce the co-crystal formation of TPeCA,which was prior to the endothermic peak at 173C found in the conventional DSC curve.Beyond 165C,several new IR absorption peaks at 3515,3124,1730,1710,1677,1648,1552 and 1265 cm1 corresponding to unique IR spectral peaks of intact TPeCA co-crystal were observed.The DSCeFTIR microspectroscopic results also evidenced the dimeremonomer transition of CA,but there were no markedly changes for TP or intact TPeCA co-crystal before its fusion.This strongly implies that the DSCeFTIR technique giving spectroscopic and thermodynamic information could simultaneously induce and identify the TPeCA co-crystal formation and phase transition of samples.Different storage conditions affecting the stability of both physical mixture and ground mixture of TPeCA were also determined.The physicalmixture of TPeCA after storing at 55C/75%RH condition for one day was fast transformed to TPeCA co-crystal,indicating that TPeCA co-crystal was easily induced under accelerated storage condition.While the co-crystal formed from TPeCA ground mixture was stable in both 25C/75%RH and 55C/75%RH conditions.展开更多
基金Supported by the National Natural Science Foundation of China (No. 29836130).
文摘p-Aminobenzenesulfonic acid was selected as a typical solute withamphoteric functional groups to be separated from dilute solution. Aquaternary ammonium chloride, Aliquat 336, was used as theextractant. The effects of pH, extractant concentration and diluenttypes on distribution coefficient, D, were investigated. Meanwhile,the ion exchange reaction for Aliquat 336 with p-aminobenzenesulfonicacid in the extraction process Was discussed. The description of Dwas proposed according to the mass action law.
基金We are grateful for financial support from the National Natural Science Foundation of China(Nos.21771193 and 22275210)Key Research and Development Projects of Shandong Province(No.2019JZZY010331).
文摘It is of great significance to develop high-temperature anhydrous proton conducting materials.Herein,we report a new strategy to significantly enhance the proton conductivity of covalent organic frameworks(COFs)through expanding the dimensionality of proton conduction.Three COF-based composites,COF-1@PA,COF-2@PA,and COF-3@PA(PA:phosphoric acid),are prepared by PA doping of three COFs with similar pore sizes but different amounts of hydrophilic groups.With the increase of hydrophilic groups,COFs can load more PA because of the enhanced hydrogen–bonding interactions between PA and the frameworks.powder X-ray diffraction(PXRD),scanning electron microscopy(SEM),and two-dimensional(2D)solid-state nuclear magnetic resonance(NMR)analyses show that PA can not only enter the channels of COF-3,but also insert into its 2D interlayers.This expands the proton conduction pathways from one-dimensional(1D)to three-dimensional(3D),which greatly improves the proton conductivity of COF-3.Meanwhile,the confinement effect of 1D channels and 2D layers of COF-3 also makes the hydrogen-bonded networks more orderly in COF-3@PA-30(30μL of PA loaded on COF-3).At 150℃,COF-3@PA-30 exhibits an ultrahigh anhydrous proton conductivity of 1.4 S·cm−1,which is a record of anhydrous proton conductivity reported to date.This work develops a new strategy for increasing the proton conductivity of 2D COF materials.
基金This work was supported by National Science Council,Taipei,Taiwan(NSC 100-2320-B-264-001-MY3).
文摘A simultaneous differential scanning calorimetryeFourier transform infrared(DSCeFTIR)microspectroscopy was used to quickly investigate the co-crystal formulation between anhydrous theophylline(TP)and anhydrous citric acid(CA)in a one-step procedure.The raw materials of TP andCA,aswell as the intactTPeCA co-crystal prepared by slow solvent evaporation were also respectively examined by this approach.The result indicates that the TPeCA cocrystal formulation was easily induced using this DSCeFTIR technique.The thermaldependent changes in three-dimensional FTIR spectral contour profiles were started from 165C to induce the co-crystal formation of TPeCA,which was prior to the endothermic peak at 173C found in the conventional DSC curve.Beyond 165C,several new IR absorption peaks at 3515,3124,1730,1710,1677,1648,1552 and 1265 cm1 corresponding to unique IR spectral peaks of intact TPeCA co-crystal were observed.The DSCeFTIR microspectroscopic results also evidenced the dimeremonomer transition of CA,but there were no markedly changes for TP or intact TPeCA co-crystal before its fusion.This strongly implies that the DSCeFTIR technique giving spectroscopic and thermodynamic information could simultaneously induce and identify the TPeCA co-crystal formation and phase transition of samples.Different storage conditions affecting the stability of both physical mixture and ground mixture of TPeCA were also determined.The physicalmixture of TPeCA after storing at 55C/75%RH condition for one day was fast transformed to TPeCA co-crystal,indicating that TPeCA co-crystal was easily induced under accelerated storage condition.While the co-crystal formed from TPeCA ground mixture was stable in both 25C/75%RH and 55C/75%RH conditions.
