The  optimization of the process of water-ethanol extraction of ethanol-lignin from Siberian larch wood was carried out  by calculation methods. A two-parameter mathematical model of the extraction process based on the  central second-order Kono composite plan was created. The influence of two parameters - the concentration of aqueous ethanol and temperature - on the yield of ethanollignin was studied. It was shown that the selected  parameters are statistically independent of each other. The response surface is a parabolic cylinder.

Optimal conditions for the process of  the larch  wood  extraction which corresponds to  the maximum yield of ethanollignin  were determined: temperature 220 ° C and ethanol concentration 70% vol.