January 28, 2020
Low-energy synthesis possible with this highly active and reusable immobilized catalyst
A joint research group from RIKEN CSRS, the Institute for Molecular Science, Chubu University, the Tokyo Institute of Technology and Kyushu University have developed an immobilized catalyst that, compared with conventional homogeneous and heterogeneous catalysts, has high-activity (provides high yields with small catalyst amounts) and is highly reusable. This catalyst was used to successfully synthesize second-generation biodiesel fuel that is carbon neutral and saves resources and energy.
Countermeasures for global warming are now a pressing issue, and biodiesel fuel is expected to become a substitute for fossil fuel. In particular, second-generation hydrocarbons have high energy efficiency and are less likely to decompose than the first-generation biodiesels made of fatty acid methyl esters. Efficient production methods for second-generation biodiesel fuels have therefore been highly desired.
The catalyst, called SiNA-Rh, is made of rhodium nanoparticles immobilized on a silicon nanostructure. Using the SiNA-Rh catalyst at a 1/2000 mol equivalent (0.05 mol%), which is 30 to 100 times smaller than existing catalysts, the free fatty acids derived from raw biomass were heated to 200°C in a hydrogen atmosphere with microwave irradiation. When the reduction reaction was carried out at a steady 200°C temperature, the yield of corresponding hydrocarbons was greater than 90%. Since microwave irradiation uses 40W, energy savings were also achieved. Repeated use experiments demonstrated that the SiNA-Rh catalyst can be reused 20 times while retaining its high activity.
The results of this research are expected to contribute to the development of efficient production processes for second-generation biodiesel fuel, as well as to the synthesis of useful substances such as pharmaceuticals and organic semiconductors.
ACS Catalysis doi:10.1021/acscatal.9b04784
H. Baek, K. Kashimura, T. Fujii, S. Tsubaki, Y. Wada, S. Fujikawa, T. Sato, Y. Uozumi, Y. M. A. Yamada,
"Production of Bio Hydrofined Diesel, Jet Fuel, and Carbon Monoxide from Fatty Acids Using a Silicon Nanowire Array-Supported Rhodium Nanoparticle Catalyst under Microwave Conditions".
Green Nanocatalysis Research Team