Lignin is the second major component of lignocellulosic biomass and represents the most important source of aromatics in nature. However, traditionally lignin has being considered as a waste or used for energy generation in pulp and paper mills. Lignin can be used in a wider range of fields, among all applications, small aromatic building blocks from lignin will be needed in order to satisfy the enormous and diverse industrial demand for aromatics.
The problem is that the lignin has different structure and composition depending on used raw material and the extraction process.
This study was aimed to characterize the composition and structure of precipitated Kraft lignin using different organic alcohols such as methanol, n-propanol, butanol and ethanol in the presence or absence of CaCl2, being an alternative to acid precipitation. Moreover, the influence of calcium chloride salts addition and alcohol/liquor ratios were assessed. Lignin samples were characterized by FTIR. Furthermore, the amount of carboxyl groups and also the antioxidant potential of lignin using ABTS techniques and Folin-Ciocalteu, DPPH were determined. Lignin showed variable composition according to the process used for precipitation.