The most important extraction
technique nowadays is simple solvent extraction. The traditional solvent for extraction was benzene, but this
has been superseded by other solvents because of concern over the possible
toxic effects of benzene on those working with it. Petroleum ether, acetone,
hexane and ethyl acetate, together with various combinations of these, are
typical solvents used for extraction.
The product of such extractions is
called a concrete or resinoid. It can be extracted with ethanol to yield an absolute, or
distilled to give an essential oil.