Crude Tall Oil (CTO) is a dark-colored, viscous liquid that has a distinct odor. It is made up of various organic compounds, including resin acids, unsaturated acids, fatty acids, and fatty alcohols. The oil is obtained from the treatment of sulfate soap with sulfuric acid, which is typically produced during the pulping process of wood using the sulfate method.
CTO can be further refined to different fractions like fatty acids, rosins, and sterols.