Ruthenium-Catalyzed Homogeneous Hydrogenation Of Ethylene Carbonate

Fossil fuels have been utillized extensively in the last few decades, causing the increasing amount of carbon dioxide in atmosphere and global problems such as "Greenhouse Effect". Therefore, reducing the emission of carbon dioxide as well as recycling of this greenhouse gas is a task without delay. It is well known that organo carbonate can be easily prepared from carbon dioxide in industry. As a result, methanol will be obtained from hydrongenation of carbonate, which would be an indirect route from carbon dioxide to methanol and proffer a practicable solution for "Greenhouse Effect"In this paper, an efficient mild reaction system of homogeneous hydrogenation of ethylene carbonate was explored. The hydrongenation reaction provides a novel approach to recycling of carbon dioxide.1. Series of ligands and complexes were designed and prepared, which were applied as catalysts for hydrogenation of carbon dioxide respectively. In addition, other factors including solvent, pressure and temperature were optimized. According to the experiment results, Cat.1bearing the Ru-CNN Pincer structure was the most active catalyst among all the catalysts screened. In the presence of Cat.1(1mol%) and KO’Bu (25mol%) at120℃under3MPa of hydrogen pressure for72h, hydrogenation of ethylene carbonate proceeded effectively and afford corresponding methanol and glyxol in about90%yield and selectivity.2. It is the first report involving ruthenium-catalyzed homogeneous hydrongenation of ethylene carbonate. Under mild condition, treated with Ru-CNN Pincer complex in hydrogen atmosphere, ethylene carbonate transforms into methanol successfully, with glyxol as a joint-product.