Lignin-based polyols

A process to manufacture lignin-based polyols, which comprises:

• a) Dissolving lignin and an acidic catalyst in an organic solvent or a mixture thereof;
• b) Adjusting the temperature of the solution obtained in step a) at a value from −15° C. to 60° C. under stirring;
• c) Adding continuously an oxirane or a solution of an oxirane in an organic solvent or a mixture thereof, on the solution obtained in step b) at a flow rate from 0.01 to 1.0 L-oxirane/h/kg-lignin,
• d) Keeping the reaction mixture obtained in step c) after addition completion for an appropriate time;
• e) Neutralizing the catalyst by adding an appropriate amount of a base on the reaction mixture obtained in step d);
• and
• f) Isolating the lignin-based polyols from the mixture obtained in step e).