Ca/SBA-15 solid bases with different Ca/Si atomic ratios were prepared by a one-pot route and employed as catalysts for the production of poly（isosorbide carbonate） （PIC） from diphenyl carbonate and isosorbide via...Ca/SBA-15 solid bases with different Ca/Si atomic ratios were prepared by a one-pot route and employed as catalysts for the production of poly（isosorbide carbonate） （PIC） from diphenyl carbonate and isosorbide via a transesterification polymerization process. The relationship between physicochemical properties and catalytic performance for Ca/SBA-15 in this melt process was investigated by means of various characterization techniques. It was found that basic site amount and strength were responsible for this transesterification process; the weak and medium basic sites inclined to promote polycondensation reaction. It was worth noting that strong basic sites could favor the decomposition of the resultant P/C, resulting in the decrease of weight-average molecular weight （Mw） and yield, and the sample with Ca/Si atomic ratio of 0.4 exhibited the best catalytic performance, giving PIC with Mw of 4.88 × 10^4 g/mol and Tg of 169 ℃ at the optimal conditions. This excellent activity can be ascribed to the presence of rich basic sites and specific basic strength on the surface of 0.4Ca/SBA-15.展开更多
Mg-A1 mixed oxides with different Mg/A1 molar ratio were prepared by thermal decomposition of hydrotalcite- like precursors at 500 ℃ for 5.0 h and used as catalysts for the transesterification of diphenyl carbonate w...Mg-A1 mixed oxides with different Mg/A1 molar ratio were prepared by thermal decomposition of hydrotalcite- like precursors at 500 ℃ for 5.0 h and used as catalysts for the transesterification of diphenyl carbonate with 1,4-butanediol to synthesize high-molecular-weight poly（butylene carbonate） （PBC）. The structure-activity correlations of these catalysts in this transesterification process were discussed by means of various characterization techniques. It was found that the chain growth for the formation of PBC can only be obtained through connecting -OH and -OC（C）OC6H5 end-group upon removing the generated phenol, and the sample with Mg/A1 molar ratio of 4.0 exhibited the best catalytic performance, giving PBC with Mw of 1.64 × 105 g/mol at 210℃ for 3.0 h. This excellent activity depended mainly on the specific surface area and basicity rather than pore structure or crystallite size of MgO.展开更多
In this paper, a new anionic metal-organic framework, [In(PBPTTBA)][(CH_3)_2 NH_2](BUT-29) has been synthesized through the reaction of tetratopic acid ligand with double Lewis pyridine sites, 4,4',4'',4&#...In this paper, a new anionic metal-organic framework, [In(PBPTTBA)][(CH_3)_2 NH_2](BUT-29) has been synthesized through the reaction of tetratopic acid ligand with double Lewis pyridine sites, 4,4',4'',4'''-(4,4'-(1,4-phenylene)bis(pyridine-6,4,2-triyl)) tetrabenzoic acid(H_4 PBPTTBA) and In(NO_3)_2·5H_2O and fully characterized by single-crystal X-ray diffraction(SXRD), powder X-ray diffraction(PXRD),thermogravimetric analysis(TGA), infrared spectroscopy(IR), and elemental analysis(EA). BUT-29 can be used as an efficient adsorbent for the selective removal of organic cationic dyes in N,N0-dimethylformamide(DMF) solution. The adsorption capacities of BUT-29 toward methylene blue and crystal violet at 298 K can reach 1119 mg/g and 832 mg/g, respectively. Moreover, the adsorbed dyes can be released in the DMF solution of LiNO_3 gradually.展开更多
基金financially supported by the National Key R&D Program of China(No.2016YFB0301900)the Science and Technology Support Program of Sichuan Province(No.2015GZ0065)
文摘Ca/SBA-15 solid bases with different Ca/Si atomic ratios were prepared by a one-pot route and employed as catalysts for the production of poly（isosorbide carbonate） （PIC） from diphenyl carbonate and isosorbide via a transesterification polymerization process. The relationship between physicochemical properties and catalytic performance for Ca/SBA-15 in this melt process was investigated by means of various characterization techniques. It was found that basic site amount and strength were responsible for this transesterification process; the weak and medium basic sites inclined to promote polycondensation reaction. It was worth noting that strong basic sites could favor the decomposition of the resultant P/C, resulting in the decrease of weight-average molecular weight （Mw） and yield, and the sample with Ca/Si atomic ratio of 0.4 exhibited the best catalytic performance, giving PIC with Mw of 4.88 × 10^4 g/mol and Tg of 169 ℃ at the optimal conditions. This excellent activity can be ascribed to the presence of rich basic sites and specific basic strength on the surface of 0.4Ca/SBA-15.
基金financially supported by the National Key Technology Pillar Program(No.2013BAC11B05)Key Research and Innovation Program of Jiangsu Province(No.BE2015055)the Science&Technology Pillar Program in Sichuan Province(No.2016GZ0228)
文摘Mg-A1 mixed oxides with different Mg/A1 molar ratio were prepared by thermal decomposition of hydrotalcite- like precursors at 500 ℃ for 5.0 h and used as catalysts for the transesterification of diphenyl carbonate with 1,4-butanediol to synthesize high-molecular-weight poly（butylene carbonate） （PBC）. The structure-activity correlations of these catalysts in this transesterification process were discussed by means of various characterization techniques. It was found that the chain growth for the formation of PBC can only be obtained through connecting -OH and -OC（C）OC6H5 end-group upon removing the generated phenol, and the sample with Mg/A1 molar ratio of 4.0 exhibited the best catalytic performance, giving PBC with Mw of 1.64 × 105 g/mol at 210℃ for 3.0 h. This excellent activity depended mainly on the specific surface area and basicity rather than pore structure or crystallite size of MgO.
文摘采用共沉淀的方法制备了系列镁铝水滑石衍生复合氧化物,分别考察了煅烧温度、反应温度、水蒸气体积分数以及碱金属添加对材料COS水解反应活性的影响.通过X射线衍射仪(XRD)、气体吸附仪(BET)、程序升温脱附(TPD)和X射线光电子能谱(XPS)等对复合氧化物的晶体结构、比表面积、孔结构和碱性位分布等进行表征.结果表明,水解反应活性随煅烧温度的增加先升高后减小,650℃煅烧制备的复合氧化物材料具有最佳的水解反应活性(COS完全转化的维持时间为180min).反应温度的升高有利于水解活性的提高,从70℃起水解反应就具有很高的活性和稳定性.此外,Cs的添加有利于水解反应活性的提高,掺杂后材料COS完全转化的维持时间达到了480 min.
基金financially supported by the National Natural Science Foundation of China (NSFC, No. U1407119)
文摘In this paper, a new anionic metal-organic framework, [In(PBPTTBA)][(CH_3)_2 NH_2](BUT-29) has been synthesized through the reaction of tetratopic acid ligand with double Lewis pyridine sites, 4,4',4'',4'''-(4,4'-(1,4-phenylene)bis(pyridine-6,4,2-triyl)) tetrabenzoic acid(H_4 PBPTTBA) and In(NO_3)_2·5H_2O and fully characterized by single-crystal X-ray diffraction(SXRD), powder X-ray diffraction(PXRD),thermogravimetric analysis(TGA), infrared spectroscopy(IR), and elemental analysis(EA). BUT-29 can be used as an efficient adsorbent for the selective removal of organic cationic dyes in N,N0-dimethylformamide(DMF) solution. The adsorption capacities of BUT-29 toward methylene blue and crystal violet at 298 K can reach 1119 mg/g and 832 mg/g, respectively. Moreover, the adsorbed dyes can be released in the DMF solution of LiNO_3 gradually.
