synthesized and employed as catalysts for hydrogenation of cinnamaldehyde in pure water. A synergy between water and bimetallic PtFe catalysts has allowed the efficiently selective production of cinnamylalcohol. With the aid of water, an initial reaction rate of >1200 h−1 and a high selectivity of >97%, as well as a good cycling stability, were achieved with a Pt3Fe/CNT catalyst under mild reaction conditions
合成了一系列碳纳米管(CNT)负载的双金属PtFe纳米颗粒,并将其用作在纯水中将肉桂醛加氢的催化剂。水与双金属PtFe催化剂之间的协同作用使肉桂醇得以有效地选择性生产。借助水,在温和的反应条件下,使用Pt 3 Fe / CNT催化剂可实现> 1200 h -1的初始反应速率和> 97%的高选择性以及良好的循环稳定性。同位素标记研究和理论计算结果表明,与水有关的氢交换途径的能垒较低,与直接H 2途径并存。离解-氢化。这项工作还表明水通过充当氢交换桥参与了催化氢化反应。
Undesirable deprotection of O-TBDMS groups by Pd/C-catalyzed hydrogenation and chemoselective hydrogenation using a Pd/C(en) catalyst
作者:Kazuyuki Hattori、Hironao Sajiki、Kosaku Hirota
DOI:10.1016/s0040-4020(01)00060-6
日期:2001.3
In general, O-TBDMS protective groups have been believed to be stable toward Pd/C-catalyzed hydrogenation conditions. In practice, however, frequent and unexpected loss of the TBDMS protective group of a variety of hydroxyl functions occurred under neutral and mild hydrogenation conditions using 10% Pd/C in MeOH. When a 10% Pd/C-ethylenediamine complex catalyst [10% Pd/C(en)] was used instead of 10% Pd/C, the undesirable problem was perfectly overcome and the chemoselective hydrogenation of reducible functionalities leaving intact the TBDMS protective group was achieved. (C) 2001 Elsevier Science Ltd. All rights reserved.