Department of Chemical Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan.
National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu 30076, Taiwan.
ACS Appl Mater Interfaces. 2020 Dec 9;12(49):54851-54861. doi: 10.1021/acsami.0c17612. Epub 2020 Nov 24.
A reduction-silylation-reduction method was developed to synthesize hydrophobic Cu catalysts derived from Cu phyllosilicates (CuPS). Triethoxy(octyl)silane (OTS) was used as the coupling agent. The OTS-grafted, reduced CuPS catalysts were applied in the hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL). The most promising catalyst was synthesized by reducing CuPS at a high temperature (350 °C for 3 h), followed by OTS grafting, and then by repeating the previous reduction step. High LA conversion (95.7%), GVL yield (85.2%), and stability (3 cycles with a 7.5% loss of initial activity) were obtained at a mild reaction condition (130 °C with a H pressure of 12 bar). A high reduction temperature not only leads to a low oxidation state of Cu species but also suppresses the formation of silylation-induced acids. Moreover, the intrinsic activity of a reduced CuPS catalyst was nearly intact after subjecting to silylation and the second reduction treatment.
发展了一种还原-硅烷化-还原方法，用于合成源自铜层状硅酸盐（CuPS）的疏水性 Cu 催化剂。三乙氧基（辛基）硅烷（OTS）被用作偶联剂。OTS 接枝还原后的 CuPS 催化剂被用于将乙酰丙酸（LA）加氢转化为γ-戊内酯（GVL）。通过在高温（350°C 下 3 小时）还原 CuPS，然后进行 OTS 接枝，然后重复之前的还原步骤，合成了最有前途的催化剂。在温和的反应条件（130°C，H 压力为 12 巴）下，可获得高的 LA 转化率（95.7%）、GVL 收率（85.2%）和稳定性（3 个循环，初始活性损失 7.5%）。高还原温度不仅导致 Cu 物种的氧化态较低，而且抑制了硅烷化诱导酸的形成。此外，经硅烷化和第二次还原处理后，还原后的 CuPS 催化剂的固有活性几乎保持不变。
