Purification of tall oil fatty acids by removing of stilbenes

The composition of tall oil fatty acids includes rosin acids and unsaponifiable substances as impurities. The latter include stilbenes. The total content of stilbenes in tall oil and fatty acids can reach 1%. The presence of stilbenes contributes to the deterioration of fatty acids color during storage and production of some derivatives. The existing methods for removing stilbenes are based on the treatment of sorbents, formaldehyde and boron trifluoride etherate. The phosphorus pentoxide treatment has a purifying effect, which allowed reducing the pinosylvin ethers content to 0.05%.