La修饰的Co-B非晶态催化剂用于乳酸乙酯选择性加氢制1,2-丙二醇  

Selective Hydrogenation of Ethyl Lactate to 1,2-Propanediol over the La-doped Co-B Amorphous Catalyst

作　　者：沈美玉[1] 王晓月[1] 孙德[1] 赵凤伟[1] 杜长海[1] 

机构地区：[1]长春工业大学化学工程学院,吉林长春130012

出　　处：《分子催化》2016年第1期1-9,共9页Journal of Molecular Catalysis(China)

基　　金：吉林省科技厅自然科学基金(201215117)资助项目~~

摘　　要：用化学还原法制备了La修饰的Co-B非晶态合金催化剂(Co-La-B),并考察了其在乳酸乙酯液相加氢制1,2-丙二醇(1,2-PDO)反应中的催化性能.通过X射线粉末衍射(XRD)、透射电子显微镜(TEM)、比表面积测定(BET)、差示扫描量热(DSC)、电感耦合等离子发射光谱(ICP-OES)、X射线光电子能谱(XPS)、氢气化学吸附、氢气程序升温脱附(H2-TPD)等手段对催化剂进行表征,研究了稀土助剂La对Co-B催化剂催化性能的影响.结果表明,活性组分Co以元素态和氧化态两种形式存在于Co-La-B非晶态合金催化剂中,催化剂中存在B向Co的电子转移,富电子的Co用于活化氢,氧化态形式存在的La3+促进了B向Co的电子转移;适量的La能提高催化剂的热稳定性,显著减小催化剂粒径,使催化剂形成更加单一的Co吸附活性位,有利于吸附活化的氢促进加氢反应进行.在氢气压力6 MPa,反应温度433 K,反应时间9 h的条件下,0.5%Co-La-B催化剂表现出最优的催化加氢性能,乳酸乙酯的转化率达到99.7%,1,2-丙二醇的选择性达到98.5%.The La-doped Co-B amorphous alloy catalyst（ Co-La-B） was prepared by the chemical reduction method for liquid phase hydrogenation of ethyl lactate to 1,2-propanediol（ 1,2-PDO）. The Co-La-B catalysts were characterized using X-ray diffraction（ XRD）,transmission electron microscopy（ TEM）,physical adsorption（ BET）,differential scanning calorimetry（ DSC）,inductively coupled plasma atomic emission spectrometry（ ICP-AES）,Xray photoelectron spectroscopy（ XPS）,hydrogen chemisorption and H2temperature-programmed desorption（ H2-TPD）. The effects of the La content on the hydrogenation of ethyl lactate were investigated. At a suitable La content,the Co-La-B amorphous alloy catalyst exhibited higher activity and selectivity than the Co-B catalyst in the hydrogenation. With the increase of La,the activity first increased and then decreased. The optimum theoretical La content was 0. 5%（ mole ratio）,at which the conversion of ethyl lactate could reach 99. 7% and the selectivity of1,2-propanediol could reach 98. 5%. The promoting effect of the La-dopant could be attributed to the dispersing effect that resulted in the higher thermal stability and appropriate particle size,unique Co active sites and electron transfer effect between Co and B.

关 键 词：非晶态合金 助剂La 催化加氢 乳酸乙酯 Co-La-B 1 2-丙二醇 

分 类 号：O643.3[理学—物理化学]