Selective deoxygenation of lignin during catalytic fast pyrolysis

Catalytic fast pyrolysis of lignin was investigated in a pyroprobe microreactor with different catalysts, including (non-)acidic alumina silicates, transition metal oxides, and zeolite-supported transition metals. The results indicate that the selectivity to the desired product can be controlled to some extent. Non-catalytic fast pyrolysis yields a complex mixture of valuable chemicals, such as vanillin, guaiacol, phenols and aromatic hydrocarbons. Therefore, a separation-purification process is necessary before the product steam can be used, thus increasing the overall cost of the process. Deoxygenation can be done efficiently to give a small amount of different products, mainly aromatic hydrocarbons. These aromatics can be used as platform chemicals using current technology, such as further hydrogenation for fuels. Strong variation in selectivity was observed depending on the catalyst. A high yield of vanillin was obtained over copper oxide. The development of highly active and selective catalysts would significantly improve the feasibility, economics and performance of catalytic fast pyrolysis of lignin.