In the selected experimental conditions, firstly, the branched products with functional groups, N-（2-hydroxylpropylphenylether） （3-aminopropyl） triethoxysilane （APES-PGE, containing one hydroxyl group） and N-[di...In the selected experimental conditions, firstly, the branched products with functional groups, N-（2-hydroxylpropylphenylether） （3-aminopropyl） triethoxysilane （APES-PGE, containing one hydroxyl group） and N-[di（2-hydroxylpropylphenylether）]（3-aminopropyl） triethoxysilane （APES-PGE2, containing two hydroxyl groups）, were synthesized by reacting 1 mole of （3-aminopropyl）triethoxysilane （APES） with 2 mole of phenylglycidylether （PGE）. Then the hydrolytic condensation of APES-PGE and APES-PGE2 was performed by dissolving 1 g of the corresponding silane in 1.5 ml tetrahydrofuran （THF）, adding water and eventually a catalyst （molar ratios: [H2O]/Si=3, [NaOH]/Si=0.05）, and heating at 50 ℃ for 24 h, allowing continuous evaporation of volatiles. The final products with branches containing hydroxyl groups were polyhedral oligomeric silsesquioxanes （POSS）. The products from two reactions were characterized by standard spectroscopic techniques, gel partition chromatography （GPC）, Fourier-transformed infrared spectroscopy （FTIR） and matrix-assisted ultraviolet laser desorption/ionization time-of-flight mass spectrometry （UV-MALDI-TOF MS）. Additionally, a narrow mass distribution of multifunctionalized POSS was shown by UV-MALDI-TOF MS and assignments of the MS peaks.展开更多
The reaction mechanism of glyoxal （G） with urea （U） under weak acid condition was theoretically investigated at PW91/DNP/COSMO of quantum chemistry using density functional theory （DFT） method. The results show ...The reaction mechanism of glyoxal （G） with urea （U） under weak acid condition was theoretically investigated at PW91/DNP/COSMO of quantum chemistry using density functional theory （DFT） method. The results show that the addition reaction of G with U under the conditions mainly involves the reactions of U with protonated glyoxal （p-G）, protonated 2,2-dihy- droxyacetaldehyde （p-G 1） and protonated bis-hemdiol （p-G2） to form two important carbocation reactive intermediates of C-p-UG and C-p-UG1, and two important hydroxyl compounds of UG and UG1. These compounds play important roles in the formation of UG resin. According to the result of quantum chemical calculation, UG resin was synthesized successfully under weak acid conditions. The UG resin was characterized by matrix assisted laser desorption ionization time of flight mass spectrometry （MALDI-TOF-MS）, ultraviolet and visible spectroscopy （UV-vis）, Fourier transform infrared spectroscopy （FT1R） and nuclear magnetic resonance spectroscopy （13CNMR and 1HNMR）. These instrumental analytical results agree with each other and further confirm the addition reaction pathway of glyoxal with urea proposed by quantum chemical calculation.展开更多
文摘In the selected experimental conditions, firstly, the branched products with functional groups, N-（2-hydroxylpropylphenylether） （3-aminopropyl） triethoxysilane （APES-PGE, containing one hydroxyl group） and N-[di（2-hydroxylpropylphenylether）]（3-aminopropyl） triethoxysilane （APES-PGE2, containing two hydroxyl groups）, were synthesized by reacting 1 mole of （3-aminopropyl）triethoxysilane （APES） with 2 mole of phenylglycidylether （PGE）. Then the hydrolytic condensation of APES-PGE and APES-PGE2 was performed by dissolving 1 g of the corresponding silane in 1.5 ml tetrahydrofuran （THF）, adding water and eventually a catalyst （molar ratios: [H2O]/Si=3, [NaOH]/Si=0.05）, and heating at 50 ℃ for 24 h, allowing continuous evaporation of volatiles. The final products with branches containing hydroxyl groups were polyhedral oligomeric silsesquioxanes （POSS）. The products from two reactions were characterized by standard spectroscopic techniques, gel partition chromatography （GPC）, Fourier-transformed infrared spectroscopy （FTIR） and matrix-assisted ultraviolet laser desorption/ionization time-of-flight mass spectrometry （UV-MALDI-TOF MS）. Additionally, a narrow mass distribution of multifunctionalized POSS was shown by UV-MALDI-TOF MS and assignments of the MS peaks.
基金Supported by the Key Program of the National Natural Science Foundation of China(No.30930074)National Natural Science Foundation of China(No.31260160)
文摘The reaction mechanism of glyoxal （G） with urea （U） under weak acid condition was theoretically investigated at PW91/DNP/COSMO of quantum chemistry using density functional theory （DFT） method. The results show that the addition reaction of G with U under the conditions mainly involves the reactions of U with protonated glyoxal （p-G）, protonated 2,2-dihy- droxyacetaldehyde （p-G 1） and protonated bis-hemdiol （p-G2） to form two important carbocation reactive intermediates of C-p-UG and C-p-UG1, and two important hydroxyl compounds of UG and UG1. These compounds play important roles in the formation of UG resin. According to the result of quantum chemical calculation, UG resin was synthesized successfully under weak acid conditions. The UG resin was characterized by matrix assisted laser desorption ionization time of flight mass spectrometry （MALDI-TOF-MS）, ultraviolet and visible spectroscopy （UV-vis）, Fourier transform infrared spectroscopy （FT1R） and nuclear magnetic resonance spectroscopy （13CNMR and 1HNMR）. These instrumental analytical results agree with each other and further confirm the addition reaction pathway of glyoxal with urea proposed by quantum chemical calculation.
