Guayule extractables: Influence of extraction conditions on yield and composition

• Published in: Biomass 1988, Vol.17 (4), p.239-249
• Main Authors: Schloman, William W., Carlson, David W., Hilton, Ashley S.
• Format: Article
• Language: English
• Subjects: Applied sciences; by-product value; Chemical engineering; Exact sciences and technology; extraction solvent; guayule; Liquid-liquid extraction; resin; rubber
• ISSN: 0144-4565; 1878-2523
• DOI: 10.1016/0144-4565(88)90106-0

The yield and composition of the resin extracted from guayule will depend upon the choice of extraction medium. Water-soluble components, primarily polysaccharides, are entrained by solvent when the shrub is first deresinated with acetone (sequential extraction). Entrainment of water-soluble components does not occur when rubber and resin are both removed with a solvent such as the acetone-pentane azeotrope (simultaneous extraction). As a consequence, resin yield is substantially (68%) higher with sequential extraction. Resin from simultaneous extraction contains no detectable ash. While resin composition, including the levels of sesquiterpene esters, triterpene keto alcohols, and triglycerides, varies with the conditions of extraction, the total content of species bearing chemically reactive groups such as carbonyl shows little change (1.2–1.3 mmol g −1). This suggests that the water-soluble material in resin from sequential extraction contains components suitable for commercially valuable derivatization. Rubber yield and molecular weight are unaffected by the choice of extraction medium.