A reaction coupling system of transesterification and methoxycarbonylation with methyl phenyl carbonate （MPC） as intermediate was established to efficiently prepare 1,6-hexamethylene diurethane （HDU） from 1,6- bex...A reaction coupling system of transesterification and methoxycarbonylation with methyl phenyl carbonate （MPC） as intermediate was established to efficiently prepare 1,6-hexamethylene diurethane （HDU） from 1,6- bexametbylene diamine （HDA）. The feasibility of the system was explored using the thermodynamics analysis, the reaction mechanism and the experiment results. The optimal reaction was carried out to get higher HDU yield. The thermodynamic analysis showed that the metboxycarbonylation of HDA with MPC, the Gibbs free energy of which was negative, was a spontaneous process. Furthermore, the equilibrium constant of the methoxycarbonylation of HDA with MPC was much greater than that of the transesterification of dimethyl carbonate （DMC） with phenol, so the reaction coupling could be realized under mild conditions. The reaction mechanism analysis indicated that phenoxy anion was the key spedes for reaction coupling. Higher MPC concentration was detected when sodium phenoxide was used as transesterification reactant with DMC, since the phenoxy anion of sodium phenoxide could be dissociated more easily. Sodium pbenoxide was more suitable to prepare HHDU through reaction coupling. A yield of HDU as high as 98.3% could be reached under the optimal conditions of mPhONa/mDMC = 0.027 and nDMC/nHDa = 8/1 at 90 ℃ in 2 h.展开更多
The 12-molybdosphoric acid mixed with titania （MPA-TiO2） was found to be a novel and efficient catalyst for the synthesis of diphenyl carbonate （DPC） via transesterification of dimethyl carbonate （DMC） and pheno...The 12-molybdosphoric acid mixed with titania （MPA-TiO2） was found to be a novel and efficient catalyst for the synthesis of diphenyl carbonate （DPC） via transesterification of dimethyl carbonate （DMC） and phenol. The X-ray diffraction （XRD） and infrared （IR） techniques were employed to characterize the prepared catalysts. The effect of the weight ratio of the 12-molybdosphoric acid to titania on the transesterification was investigated. A 13.1% yield of DPC and an 11.6% yield of methyl phenyl carbonate （MPC） were obtained over MPA-TiO2 with the weight ratio of MPA to TiO2 as 5：1.展开更多
基金Supported by the National Natural Science Foundation of China(21276126,21306089)the Jiangsu Province Higher Education Natural Science Foundation(09KJA530004,13KJB530006)
文摘A reaction coupling system of transesterification and methoxycarbonylation with methyl phenyl carbonate （MPC） as intermediate was established to efficiently prepare 1,6-hexamethylene diurethane （HDU） from 1,6- bexametbylene diamine （HDA）. The feasibility of the system was explored using the thermodynamics analysis, the reaction mechanism and the experiment results. The optimal reaction was carried out to get higher HDU yield. The thermodynamic analysis showed that the metboxycarbonylation of HDA with MPC, the Gibbs free energy of which was negative, was a spontaneous process. Furthermore, the equilibrium constant of the methoxycarbonylation of HDA with MPC was much greater than that of the transesterification of dimethyl carbonate （DMC） with phenol, so the reaction coupling could be realized under mild conditions. The reaction mechanism analysis indicated that phenoxy anion was the key spedes for reaction coupling. Higher MPC concentration was detected when sodium phenoxide was used as transesterification reactant with DMC, since the phenoxy anion of sodium phenoxide could be dissociated more easily. Sodium pbenoxide was more suitable to prepare HHDU through reaction coupling. A yield of HDU as high as 98.3% could be reached under the optimal conditions of mPhONa/mDMC = 0.027 and nDMC/nHDa = 8/1 at 90 ℃ in 2 h.
文摘The 12-molybdosphoric acid mixed with titania （MPA-TiO2） was found to be a novel and efficient catalyst for the synthesis of diphenyl carbonate （DPC） via transesterification of dimethyl carbonate （DMC） and phenol. The X-ray diffraction （XRD） and infrared （IR） techniques were employed to characterize the prepared catalysts. The effect of the weight ratio of the 12-molybdosphoric acid to titania on the transesterification was investigated. A 13.1% yield of DPC and an 11.6% yield of methyl phenyl carbonate （MPC） were obtained over MPA-TiO2 with the weight ratio of MPA to TiO2 as 5：1.
