Polyhedron lead hydroxide carbonate （2PbCO3·Pb（OH）2 ） microcrystals have been prepared in solution phase via a facile method in the presence of surfactant cetyltrimethylammonium bromide （CTAB）. All the samp...Polyhedron lead hydroxide carbonate （2PbCO3·Pb（OH）2 ） microcrystals have been prepared in solution phase via a facile method in the presence of surfactant cetyltrimethylammonium bromide （CTAB）. All the samples were characterized by powder X-ray diffraction ,pattern （XRD）, field-emission scanning electron mi- croscopy （FE-SEM）, high-resolution transmission electron microscopy （HRTEM）, and selected area electron diffraction （SAED）. The possible growth mechanism was discussed. 2PbCO3·Pb（OH）2 microcrystals were found to be a novel and efficient catalyst for the synthesis of diphenyl carbonate （DPC） by transesterification of dimethyl carbonate （DMC） with phenol. Compared with some other catalysts, such as AlCl3, ZnCl2, and Mg5（CO3）4（OH）2, 2PbCO3·Pb（OH）2 microcrystals are stable and show relatively high activity at low catalyst amount. When the reaction was carried out at 180 12, with a molar ratio of phenol to DMC of 2：1, a reaction time 14 h, and a catalyst amount 0.2% （molar ratio to phenol）, the selectivity of DPC and methyl phenyl carbonate （MPC） was 14.7% and 78.8%, respectively.展开更多
PbCO3 powders were prepared by homogeneous precipitation method using Pb(CH3COO)2·3H2O, Pb(NO3)2 and CO(NH2)2 as raw materials. Results indicated that micron-size PbCO3 powders were prepared by using Pb(NO3)2 as ...PbCO3 powders were prepared by homogeneous precipitation method using Pb(CH3COO)2·3H2O, Pb(NO3)2 and CO(NH2)2 as raw materials. Results indicated that micron-size PbCO3 powders were prepared by using Pb(NO3)2 as the lead source, but nano-size PbCO3 powders, with an average size of 20 nm, were prepared by using Pb(CH3COO)2·3H2O as the lead source. Results from combustion catalysts application in propellants show that the burning rate of the propellant can be increased 11.96% in average, but the pressure exponent of the propellant can be decreased 11.54% from nano-size PbCO3 powders to common-size PbCO3 powders.展开更多
基金Sponsored by the National Natural Science Foundation of China (20671011,20331010,90406002 and 90406024)"111"Project (B07012) Key Laboratory of Structural Chemistry Foundation,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences(060017)
文摘Polyhedron lead hydroxide carbonate （2PbCO3·Pb（OH）2 ） microcrystals have been prepared in solution phase via a facile method in the presence of surfactant cetyltrimethylammonium bromide （CTAB）. All the samples were characterized by powder X-ray diffraction ,pattern （XRD）, field-emission scanning electron mi- croscopy （FE-SEM）, high-resolution transmission electron microscopy （HRTEM）, and selected area electron diffraction （SAED）. The possible growth mechanism was discussed. 2PbCO3·Pb（OH）2 microcrystals were found to be a novel and efficient catalyst for the synthesis of diphenyl carbonate （DPC） by transesterification of dimethyl carbonate （DMC） with phenol. Compared with some other catalysts, such as AlCl3, ZnCl2, and Mg5（CO3）4（OH）2, 2PbCO3·Pb（OH）2 microcrystals are stable and show relatively high activity at low catalyst amount. When the reaction was carried out at 180 12, with a molar ratio of phenol to DMC of 2：1, a reaction time 14 h, and a catalyst amount 0.2% （molar ratio to phenol）, the selectivity of DPC and methyl phenyl carbonate （MPC） was 14.7% and 78.8%, respectively.
文摘PbCO3 powders were prepared by homogeneous precipitation method using Pb(CH3COO)2·3H2O, Pb(NO3)2 and CO(NH2)2 as raw materials. Results indicated that micron-size PbCO3 powders were prepared by using Pb(NO3)2 as the lead source, but nano-size PbCO3 powders, with an average size of 20 nm, were prepared by using Pb(CH3COO)2·3H2O as the lead source. Results from combustion catalysts application in propellants show that the burning rate of the propellant can be increased 11.96% in average, but the pressure exponent of the propellant can be decreased 11.54% from nano-size PbCO3 powders to common-size PbCO3 powders.
