The influences of adding sodium to zirconia on the acid-base properties of the surface and on the catalytic conversion of ethanol and acetone were investigated. The rates of ethanol dehydration, dehydrogenation and co...The influences of adding sodium to zirconia on the acid-base properties of the surface and on the catalytic conversion of ethanol and acetone were investigated. The rates of ethanol dehydration, dehydrogenation and coupling were evaluated in a fixed-bed flow reactor operating at temperatures from 613 to 673 K. The rate of acetone condensation was evaluated in the same reactor operating at 473-573 K. Addition of 1.0 wt% Na to ZrO2 decreased the rate of ethanol dehydration by more than an order of magnitude, which was consistent with a neutralization of acid sites evaluated by ammonia adsorption microcalorimetry. Addition of 1.0 wt% Na to ZrO2 also increased the base site density quantified by carbon dioxide adsorption microcalorimetry and the rate of acetone condensation. Although the rate of ethanol coupling was not increased by the addition of Na, the overall selectivity of ethanol to butanol was improved over the 1.0 wt% Na/ZrO2 sample because of the significant inhibition of ethanol dehydration.展开更多
Condensation and crosslinking reactions of furfuryl alcohol(FA)and FA with tris(2-hydro- xyethyl)isocyanurate(THEIC)are studied by means of DSC,TG,TBA,NMR and elemental analysis. Four exothermic peaks are observed on ...Condensation and crosslinking reactions of furfuryl alcohol(FA)and FA with tris(2-hydro- xyethyl)isocyanurate(THEIC)are studied by means of DSC,TG,TBA,NMR and elemental analysis. Four exothermic peaks are observed on the DSC curves of thermal condensation of FA and FA with THEIC in the presence of sulfuric acid.The peaks Ⅰ,Ⅱ(50—80℃),Ⅲ(110—130℃)and Ⅳ(150— 190℃)correspond to linear polycondensation of FA through head-to-tail condensation,head-to-head etherification,crosslinking dehydration reaction between methylene group and terminal hydroxy group of FA polymeric chain and to further crosslinking reaction at higher temperature,respectively.The reactivity of FA and THEIC increases sharply at 130—150℃ and THEIC is reacted completely at 150℃.Addition of THEIC raises the initial decomposition temperature of FA polymer by 60℃.展开更多
基金the Chemical Sciences,Geosciences and Biosciences Division,Office of Basic Energy Sciences,Office of Science,U.S.Department of Energy,grant no.DEFG0295ER14549
文摘The influences of adding sodium to zirconia on the acid-base properties of the surface and on the catalytic conversion of ethanol and acetone were investigated. The rates of ethanol dehydration, dehydrogenation and coupling were evaluated in a fixed-bed flow reactor operating at temperatures from 613 to 673 K. The rate of acetone condensation was evaluated in the same reactor operating at 473-573 K. Addition of 1.0 wt% Na to ZrO2 decreased the rate of ethanol dehydration by more than an order of magnitude, which was consistent with a neutralization of acid sites evaluated by ammonia adsorption microcalorimetry. Addition of 1.0 wt% Na to ZrO2 also increased the base site density quantified by carbon dioxide adsorption microcalorimetry and the rate of acetone condensation. Although the rate of ethanol coupling was not increased by the addition of Na, the overall selectivity of ethanol to butanol was improved over the 1.0 wt% Na/ZrO2 sample because of the significant inhibition of ethanol dehydration.
基金This project is supported by the National Natural Science Foundation of China.
文摘Condensation and crosslinking reactions of furfuryl alcohol(FA)and FA with tris(2-hydro- xyethyl)isocyanurate(THEIC)are studied by means of DSC,TG,TBA,NMR and elemental analysis. Four exothermic peaks are observed on the DSC curves of thermal condensation of FA and FA with THEIC in the presence of sulfuric acid.The peaks Ⅰ,Ⅱ(50—80℃),Ⅲ(110—130℃)and Ⅳ(150— 190℃)correspond to linear polycondensation of FA through head-to-tail condensation,head-to-head etherification,crosslinking dehydration reaction between methylene group and terminal hydroxy group of FA polymeric chain and to further crosslinking reaction at higher temperature,respectively.The reactivity of FA and THEIC increases sharply at 130—150℃ and THEIC is reacted completely at 150℃.Addition of THEIC raises the initial decomposition temperature of FA polymer by 60℃.
