ABSTRACT
Hydrogen peroxide is an environmentally friendly oxidizing agent but current synthetic methods are wasteful. This is a result of the high flammability of H2/O2 mixtures and/or the requirement for cocatalysts. In this paper, we report the synthesis of H2O2 by means of a homogeneous catalyst, which allows a safe, one-pot synthesis in water, using only H2 and O2. This catalyst is capable of removing electrons from H2, storing them for the reduction of O2, and then permitting the protonation of the reduced oxygen to H2O2. The turnover number (TON) is 910 under an H2/O2 (95/5) atmosphere (1.9 MPa) for 12 h at 23 °C, which is the highest of any homogeneous catalyst. Furthermore, we propose a reaction mechanism based on two crystal structures.
ABSTRACT
This paper reports the first example of C-H arylation of benzene under mild conditions, using H2 as an electron source {turnover numbers (TONs)=0.7-2.0 for 24â h}. The reaction depends on a Rh-based electron storage catalyst, and proceeds at room temperature and in aqueous solution. Furthermore, the H2 is inactive during the radical transfer step, greatly reducing unwanted side reactions.