CuO-CoO-MnO/SiO2 nanocomposite aerogels were prepared by using tetraethyl orthosilicate （TEOS） as Si source, and aqueous solution of Cu, Co and Mn acetates as transition metal sources via sol-gel process and supercr...CuO-CoO-MnO/SiO2 nanocomposite aerogels were prepared by using tetraethyl orthosilicate （TEOS） as Si source, and aqueous solution of Cu, Co and Mn acetates as transition metal sources via sol-gel process and supercritical drying （SCD） technique. The effect of synthesis conditions on gelation was investigated. Moreover, the composition of the CuO-CoO-MnO/SiO2 nanocomposite aerogels was characterized by electron dispersive spectroscopy （EDS） and X-ray photoelectron spectroscopy （XPS）, and the specific surface area of the nanocomposite aerogels was determined by the Brunauer-Emmett-Teller （BET） method. Diphenyl carbonate （DPC） as the product was analyzed by gas chromatography （GC）. The experimental results show that the range of optimal temperature for gelation is 30-45 ℃, and the pH is 3.0-4.5. CuO-CoO-MnO/SiO2 nanocomposite aerogels are porous with a specific surface area of 384.9-700.6 m2/g. Compared to CO2 SCD, ethanol SCD is even favorable to the formation of aerogel with high specific surface area. The transition metals content in the nanocomposite aerogels can be controlled to be 0.71at%-13.77at%. With CuO-CoO-MnO/SiO2 nanocomposite aerogels as catalyst carrier, the yield of DPC is in direct proportion to the atomic fraction of transition metals in the nanocomposite aerogels, and it is up to 26.31 mass%, which is much higher than that via other porous carriers.展开更多
The active intermediate'carbon radical' was detected by the spin—trapping reagent (POBN) during the debromination of Ph_2CHBr in the presence of viologen derivatives as electron—transfer catalysts(ETC).
Bisphenol A bis（diphenyl phosphate） oligomer（BDP） is prepared successfully from the reactants consisting of phosphorus oxyehloride （POCl3）, bisphenol A and phenol with a Friedel-Crafts catalyst. The resultant pr...Bisphenol A bis（diphenyl phosphate） oligomer（BDP） is prepared successfully from the reactants consisting of phosphorus oxyehloride （POCl3）, bisphenol A and phenol with a Friedel-Crafts catalyst. The resultant products were examined with thermtygravimetrie analysis （TGA） and high performance liquid chro- matography（HPLC）. Thermogravimetry data shows that BDP decomposes at 375℃ when 5 % weight lost. Experiments results show that catalyst is preferably AICI3 and the amount of it is preferably 1% relative to bisphenol A by mole. POCl3/bisphenol A mole ratio is preferably about 5：1 to 6：1. Experiments unclosed that a seal apparatus is very important to the properties of product.展开更多
基金Funded by the Hebei Natural Science Foundation(No.E2011209003)the Science and Technology Development Foundation of Hebei (No. 10215606D)the Ph D Programs Foundation of Hebei United University
文摘CuO-CoO-MnO/SiO2 nanocomposite aerogels were prepared by using tetraethyl orthosilicate （TEOS） as Si source, and aqueous solution of Cu, Co and Mn acetates as transition metal sources via sol-gel process and supercritical drying （SCD） technique. The effect of synthesis conditions on gelation was investigated. Moreover, the composition of the CuO-CoO-MnO/SiO2 nanocomposite aerogels was characterized by electron dispersive spectroscopy （EDS） and X-ray photoelectron spectroscopy （XPS）, and the specific surface area of the nanocomposite aerogels was determined by the Brunauer-Emmett-Teller （BET） method. Diphenyl carbonate （DPC） as the product was analyzed by gas chromatography （GC）. The experimental results show that the range of optimal temperature for gelation is 30-45 ℃, and the pH is 3.0-4.5. CuO-CoO-MnO/SiO2 nanocomposite aerogels are porous with a specific surface area of 384.9-700.6 m2/g. Compared to CO2 SCD, ethanol SCD is even favorable to the formation of aerogel with high specific surface area. The transition metals content in the nanocomposite aerogels can be controlled to be 0.71at%-13.77at%. With CuO-CoO-MnO/SiO2 nanocomposite aerogels as catalyst carrier, the yield of DPC is in direct proportion to the atomic fraction of transition metals in the nanocomposite aerogels, and it is up to 26.31 mass%, which is much higher than that via other porous carriers.
文摘The active intermediate'carbon radical' was detected by the spin—trapping reagent (POBN) during the debromination of Ph_2CHBr in the presence of viologen derivatives as electron—transfer catalysts(ETC).
文摘Bisphenol A bis（diphenyl phosphate） oligomer（BDP） is prepared successfully from the reactants consisting of phosphorus oxyehloride （POCl3）, bisphenol A and phenol with a Friedel-Crafts catalyst. The resultant products were examined with thermtygravimetrie analysis （TGA） and high performance liquid chro- matography（HPLC）. Thermogravimetry data shows that BDP decomposes at 375℃ when 5 % weight lost. Experiments results show that catalyst is preferably AICI3 and the amount of it is preferably 1% relative to bisphenol A by mole. POCl3/bisphenol A mole ratio is preferably about 5：1 to 6：1. Experiments unclosed that a seal apparatus is very important to the properties of product.
