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作 者:刘文欢[1] 郭鹏[1] 苏际[1] 胡佳[1] 王艳梅[1] 刘娜[2] 郭洪臣[1]
机构地区:[1]大连理工大学化工学院催化化学与工程系精细化工国家重点实验室,辽宁大连116012 [2]大连工业大学化学与材料学院,辽宁大连116034
出 处:《催化学报》2009年第6期482-484,共3页
基 金:国家自然科学基金(20233050)
摘 要:采用Hammett指示剂滴定法表征了钛硅沸石TS-1的酸性.结果表明,TS-1酸强度范围为+3.3<H0≤+4.8.其中,在+3.85<H0≤+4.8范围的弱酸中心可能与TS-1骨架钛有关,而在+3.3<H0≤+3.85的较强酸中心则可能与无定形的六配位非骨架钛有关.TS-1上的较强酸中心能够显著地催化环氧丙烷与甲醇的醚化反应,而TS-1上的弱酸中心对该反应几乎没有催化活性,但弱酸中心对乙二胺环胺化生成哌嗪和三乙烯二胺反应具有高活性和高选择性.这表明TS-1作为一种弱的固体酸催化剂,有可能应用于选择氧化以外的催化反应.Hammett indicator titration was used for the characterization of TS-1 acidity. The acid strength of the TS-1 studied was +3.3 〈 H0 ≤ +4.8. The weaker acid sites, +3.85 〈 H0 ≤ +4.8, were due to the framework Ti of TS-1, while the stronger acid sites, +3.3 〈 H0 ≤ +3.85, in micron-sized TS-1 samples were due to amorphous extraframework Ti species. The stronger acid sites showed a correlation with the conversion of propylene oxide in the etherification with methanol. The weaker acid sites, although too weak for the etherification of PO with methanol, were active and selective for converting ethyldiamine (EDA) into piperazine (PIP) and 1,4-diazabicyclo[2.2.2]octane (DABCO). TS-1 as a weak solid acid was shown to be a promising catalyst for reactions like the cycloamination of EDA to PIP and DABCO.
关 键 词:钛硅分子筛 酸性 Hammett指示剂 醚化反应 环胺化反应
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