Bronsted acidic ionic liquids based on imidazolium cation were employed as efficient catalysts and mediums for the ring opening of phthalic anhydride to synthesize half-esters. Good yields, short reaction time and mil...Bronsted acidic ionic liquids based on imidazolium cation were employed as efficient catalysts and mediums for the ring opening of phthalic anhydride to synthesize half-esters. Good yields, short reaction time and mild reaction condition were achieved. Lower acidity of ionic liquid resulted in higher catalytic selectivity in the synthesis of half-esters. The minimum-energy geometries of sulfonic acid-functionalized ionic liquids based on imidazolium cation revealed that their acidities and catalytic selectivity in the synthesis of half-esters were related to their structures.展开更多
用X射线衍射 (XRD)、激光拉曼光谱 (LRS)、程序升温还原 (TPR)和微型反应测试等手段研究了Bi V Mo O复合氧化物催化剂组成、结构与丙烷选择性氧化催化性能 .结果表明不同组成的Bi V Mo O复合氧化物催化剂可形成白钨矿型晶体结构 ,丙烷...用X射线衍射 (XRD)、激光拉曼光谱 (LRS)、程序升温还原 (TPR)和微型反应测试等手段研究了Bi V Mo O复合氧化物催化剂组成、结构与丙烷选择性氧化催化性能 .结果表明不同组成的Bi V Mo O复合氧化物催化剂可形成白钨矿型晶体结构 ,丙烷选择氧化催化性能与催化剂组成和结构密切相关 .Mo组分的引入使催化剂的丙烷完全氧化催化性能受到抑制 ,丙烯醛选择性增加且在Mo (V +Mo)原子比为 0 .45时达极大值 .随Mo含量进一步增加 ,催化剂的丙烯选择性增加而丙烯醛选择性下降 .LRS和TPR结果表明 ,不同组成的Bi V Mo展开更多
Surface properties （viz. surface area, basicity/base strength distribution, and crystal phases） of alkali metal doped CaO （alkali metal/Ca= 0.1 and 0.4） catalysts and their catalytic activity/selectivity in oxidat...Surface properties （viz. surface area, basicity/base strength distribution, and crystal phases） of alkali metal doped CaO （alkali metal/Ca= 0.1 and 0.4） catalysts and their catalytic activity/selectivity in oxidative coupling of methane （OCM） to higher hydrocarbons at different reaction conditions （viz. temperature, 700 and 750 ℃; CH4/O2 ratio, 4.0 and 8.0 and space velocity, 5140-20550 cm^3 ·g^-1·h^-1） have been investigated. The influence of catalyst calcination temperature on the activity/selectivity has also been investigated. The surface properties （viz. surface area, basicity/base strength distribution） and catalytic activity/selectivity of the alkali metal doped CaO catalysts are strongly influenced by the alkali metal promoter and its concentration in the alkali metal doped CaO catalysts. An addition of alkali metal promoter to CaO results in a large decrease in the surface area but a large increase in the surface basicity （strong basic sites） and the C2＋ selectivity and yield of the catalysts in the OCM process. The activity and selectivity are strongly influenced by the catalyst calcination temperature. No direct relationship between surface basicity and catalytic activity/selectivity has been observed. Among the alkali metal doped CaO catalysts, Na-CaO （Na/Ca = 0.1, before calcination） catalyst （calcined at 750 ℃）, showed best performance （C2＋ selectivity of 68.8% with 24.7% methane conversion）, whereas the poorest performance was shown by the Rb-CaO catalyst in the OCM process.展开更多
基金Supported by the Key Project of Chinese Ministry of Education (No 105075)the National Natural Science Foundation of China (No 20503016)
文摘Bronsted acidic ionic liquids based on imidazolium cation were employed as efficient catalysts and mediums for the ring opening of phthalic anhydride to synthesize half-esters. Good yields, short reaction time and mild reaction condition were achieved. Lower acidity of ionic liquid resulted in higher catalytic selectivity in the synthesis of half-esters. The minimum-energy geometries of sulfonic acid-functionalized ionic liquids based on imidazolium cation revealed that their acidities and catalytic selectivity in the synthesis of half-esters were related to their structures.
基金国家重点基础研究发展规划项目 (No .G19990 2 2 40 0 )南京大学分析测试基金资助课题
文摘用X射线衍射 (XRD)、激光拉曼光谱 (LRS)、程序升温还原 (TPR)和微型反应测试等手段研究了Bi V Mo O复合氧化物催化剂组成、结构与丙烷选择性氧化催化性能 .结果表明不同组成的Bi V Mo O复合氧化物催化剂可形成白钨矿型晶体结构 ,丙烷选择氧化催化性能与催化剂组成和结构密切相关 .Mo组分的引入使催化剂的丙烷完全氧化催化性能受到抑制 ,丙烯醛选择性增加且在Mo (V +Mo)原子比为 0 .45时达极大值 .随Mo含量进一步增加 ,催化剂的丙烯选择性增加而丙烯醛选择性下降 .LRS和TPR结果表明 ,不同组成的Bi V Mo
文摘Surface properties （viz. surface area, basicity/base strength distribution, and crystal phases） of alkali metal doped CaO （alkali metal/Ca= 0.1 and 0.4） catalysts and their catalytic activity/selectivity in oxidative coupling of methane （OCM） to higher hydrocarbons at different reaction conditions （viz. temperature, 700 and 750 ℃; CH4/O2 ratio, 4.0 and 8.0 and space velocity, 5140-20550 cm^3 ·g^-1·h^-1） have been investigated. The influence of catalyst calcination temperature on the activity/selectivity has also been investigated. The surface properties （viz. surface area, basicity/base strength distribution） and catalytic activity/selectivity of the alkali metal doped CaO catalysts are strongly influenced by the alkali metal promoter and its concentration in the alkali metal doped CaO catalysts. An addition of alkali metal promoter to CaO results in a large decrease in the surface area but a large increase in the surface basicity （strong basic sites） and the C2＋ selectivity and yield of the catalysts in the OCM process. The activity and selectivity are strongly influenced by the catalyst calcination temperature. No direct relationship between surface basicity and catalytic activity/selectivity has been observed. Among the alkali metal doped CaO catalysts, Na-CaO （Na/Ca = 0.1, before calcination） catalyst （calcined at 750 ℃）, showed best performance （C2＋ selectivity of 68.8% with 24.7% methane conversion）, whereas the poorest performance was shown by the Rb-CaO catalyst in the OCM process.
