A new catalyst,iron(Ⅱ) chelate of the schiff base derived from β-Ala and picoline,was successfully used for atom transfer radical polymerization.The reaction was carried out at 90℃ in bulk with ethyl 2-bromo-2-ethy...A new catalyst,iron(Ⅱ) chelate of the schiff base derived from β-Ala and picoline,was successfully used for atom transfer radical polymerization.The reaction was carried out at 90℃ in bulk with ethyl 2-bromo-2-ethylpropionate as the initiator.The molecular weight of the resulting polymer increases with increasing monomer conversion.The molecular weight distribution is not narrow(PDI=1.5~1.7),and the value of molecular weight detected is in good accordance with the calculated.The molecular weight distribution is 1.13 with the addition of 10% DMF.展开更多
Strontium ferrite was prepared from Strontium Waste Residue (SWR) as a material. Strontium chloride was obtained by leaching SWR with ammonia chloride, and then SrCl2 was converted to SrCO3. Strontium ferrite (SrFe12O...Strontium ferrite was prepared from Strontium Waste Residue (SWR) as a material. Strontium chloride was obtained by leaching SWR with ammonia chloride, and then SrCl2 was converted to SrCO3. Strontium ferrite (SrFe12O19) was formed by roasting the mixture of SrCO3 and FeCl3 in a proper proportion. The structure and magnetic susceptibility of strontium ferrite were investi-gated. The results showed that strontium conversion ratio increased with decreasing SWR grain diameter. The largest ratio was pre-sented when n(NH4Cl/Sr) was 3.6. What is more, the conversion process coincided with the kinetic characteristics of fractal reaction. The magnetic susceptibility of strontium ferrite decreased with increasing Fe3+/Sr2+ mole ratio and pH. SrFe12O19 exhibited face-centered and cubic closely-packed hexagonal structures. There were the strong diffraction peaks of Fe2O3 in the X-ray diffracto-gram of strontium ferrite. Strontium recovery ratio was 87.0%.展开更多
文摘A new catalyst,iron(Ⅱ) chelate of the schiff base derived from β-Ala and picoline,was successfully used for atom transfer radical polymerization.The reaction was carried out at 90℃ in bulk with ethyl 2-bromo-2-ethylpropionate as the initiator.The molecular weight of the resulting polymer increases with increasing monomer conversion.The molecular weight distribution is not narrow(PDI=1.5~1.7),and the value of molecular weight detected is in good accordance with the calculated.The molecular weight distribution is 1.13 with the addition of 10% DMF.
基金Foundation by Scientific and Technological Committee of Chongqing(CSTC,2010AC4054)
文摘Strontium ferrite was prepared from Strontium Waste Residue (SWR) as a material. Strontium chloride was obtained by leaching SWR with ammonia chloride, and then SrCl2 was converted to SrCO3. Strontium ferrite (SrFe12O19) was formed by roasting the mixture of SrCO3 and FeCl3 in a proper proportion. The structure and magnetic susceptibility of strontium ferrite were investi-gated. The results showed that strontium conversion ratio increased with decreasing SWR grain diameter. The largest ratio was pre-sented when n(NH4Cl/Sr) was 3.6. What is more, the conversion process coincided with the kinetic characteristics of fractal reaction. The magnetic susceptibility of strontium ferrite decreased with increasing Fe3+/Sr2+ mole ratio and pH. SrFe12O19 exhibited face-centered and cubic closely-packed hexagonal structures. There were the strong diffraction peaks of Fe2O3 in the X-ray diffracto-gram of strontium ferrite. Strontium recovery ratio was 87.0%.