Effect of different organosolv treatments on the structure and properties of olive tree pruning lignin

Different organosolv processes (acetosolv, formosolv and acetosolv/formosolv) were applied to extract lignin from olive tree pruning. Obtained lignins were characterized by several methods to determine their composition, structure and functional groups with the aim of evaluating their potential to be used for obtaining added value compounds. All lignins had very high purity and low sugar and inorganic contamination, especially in the case of lignin obtained from formosolv treatment. Hydroxyl groups were the main functional groups in all lignin samples while the carbonyl groups were the lowest. Finally, the main difference between the lignins was the average molecular weight.