Abietic Acid → Levopimaric acid

Beteiligte Stoffe

Reaktionsschritte

Rosin from the species pinus halepensis was analyzed for content of various types of rosin acids. The rosin had an abietic acid content of 35%, a neoabietic acid content of 15%, a palustric acid content of 17.5% and a levopimaric acid content of 12.5% giving a total of rosin acids having conjugated double bonds of 80%. The rosin was dissolved in toluene to form a 25 to 30% solution. To the solution was added concentrated sulphuric acid, with stirring and cooling. Over 2 hours the temperature rose to 40°-45° C. then fell to about 30° C. The organic and acid phases separated and the organic phase was drawn off. The solvent was removed to yield a hard dimerized rosin having a softening point of from 125° to 130° C.

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