Department of Applied Chemistry, School of Engineering, Tohoku University, 6-6-07, Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan).
ChemSusChem. 2015 Apr 13;8(7):1170-8. doi: 10.1002/cssc.201403011. Epub 2014 Dec 15.
Modification of Ru/C with a small amount of MoOx (RuMoOx /C) enhanced the catalytic activity in the hydrogenation of L-lactic acid to form 1,2-propanediol and maintained high selectivity. The turnover frequency based on the amount of Ru over the optimized RuMoOx /C catalyst (Mo/Ru molar ratio=1:16) was 114 h(-1) at 393 K, which was about 4 times higher than that over Ru/C. The same effect of MoOx was obtained over RuMoOx /SiO2 , although RuMoOx /SiO2 showed slightly lower activity than that of RuMoOx /C. RuMoOx /C achieved a high yield of 95 % in 18 h at 393 K and was applicable to various carboxylic acids to provide the corresponding alcohols in high yields. Modification with MoOx also brought about suppression of racemization and (S)-1,2-propanediol was obtained in high enantiomeric excess at 353 K. Based on kinetic analysis and characterization data, such as XRD, TEM, CO adsorption by a volumetric method, FTIR spectroscopy, and X-ray absorption spectroscopy, for RuMoOx /C and RuMoOx /SiO2 , the catalyst structure and reaction mechanism are proposed.
用少量 MoOx 对 Ru/C（RuMoOx /C）进行修饰，提高了在 L-乳酸加氢制备 1,2-丙二醇反应中的催化活性，并且保持了很高的选择性。在优化的 RuMoOx /C 催化剂（Mo/Ru 摩尔比=1:16）上，基于 Ru 量的转化频率（TOF）为 393 K 时的 114 h(-1)，是 Ru/C 的大约 4 倍。在 RuMoOx /SiO2 上也获得了 MoOx 的相同效果，尽管 RuMoOx /SiO2 的活性略低于 RuMoOx /C。在 393 K 下反应 18 h，RuMoOx /C 达到了 95%的高收率，并且适用于各种羧酸，以高产率提供相应的醇。MoOx 的修饰还带来了外消旋化的抑制，在 353 K 时可以获得高对映体过量的（S）-1,2-丙二醇。基于动力学分析和 XRD、TEM、体积法 CO 吸附、FTIR 光谱和 X 射线吸收光谱等表征数据，提出了 RuMoOx /C 和 RuMoOx /SiO2 的催化剂结构和反应机理。
