Isolation, Study and Application of Organosolv Lignins (Review)

The analysis of the literature on the methods of soluble organosolv lignins isolation, their physicalchemical study and on the method of their processing to porous aerogels and liquid hydrocarbons was carried out.A review of the literature allowed us to choice of the most important areas of research.For isolation from wood the soluble lignins free from sulfur the methods of catalytic peroxide delignification at mild conditions (temperature ≤ 100 °C, atmospheric pressure) and methods of lignin extraction by supercritical organic solvents were used.Molecular mass and molecular-mass distribution of ethanol-lignin samples isolated from aspenwood and abies-wood were studied by gel-permeation chromatography.Weighted molecular mass of ethanol-lignin from abies wood is 478 Da and that from aspen wood ethanol-lignin -750 Da.Thus, the studied samples of ethanol-lignin have rather low molecular mass, what should facilitate their further processing to liquid hydrocarbons and aerogels.For the depolymerization of organosolv lignins to liquid hydrocarbons the processes of their catalytic conversion in supercritical alcohols have good prospects for the use.In the processes of lignin thermal conversion alcohols can to extract the products of lignin depolymerization and to alkylate these products, preventing their repolymerization to high molecular mass substances.