Catalytic hydrogenolysis of different types of lignin obtained from sawdust softwood

Abstract

The article presents the results of the process of hydrogenolysis of lignin obtained by three different methods from softwood sawdust: alkaline, sulfuric acid, acetic acid. It is shown that the isolation process has a strong impact on the conversion of feedstock and on the yield of products. The maximum conversion of 67.5 % was observed in the case of acetic lignin in propanol-2 as a solvent, and the highest yield of liquid products (38.5 wt.%) was obtained in the case of using an alkali lignin. On the basis of the conducted researches it was shown that the catalytic system 3 % Ru/MN 270 is more active in the process of hydrogenolysis than 3 % Pd/MN270, but Pd requires a lower temperature and pressure for the process. When using both catalysts a large number of derivatives of phenol, which can be used as alternative fuel are formed. The optimal process conditions are: 3 % Ru/MN270 - temperature 300 °C, partial hydrogen pressure of 4 MPa, the ratio of substrate/catalyst is 20:1, for 3 % Pd/MN270 temperature 250 °C, the partial pressure of hydrogen of 2 MPa, the volume of solvent 30 mL, the ratio of substrate/catalyst 15/1