New adducts of turpentine and rosin with citraconic anhydride and itaconic acid

Abstract

The reaction of pine gum rosin, turpentine and its components (α-pinene, ∆3-carene, α-terpinene) with citraconic anhydride and itaconic acid was investigated. It was shown that α-terpinene, in contrast to α-pinene and ∆3-carene, reacts with citraconic anhydride to give the unknown cycloaddition reaction product. Its structure was studied by the 2D NMR spectroscopy. Turpentine reacts with itaconic acid forming a complex mixture that contains esters of terpenic alcohols and itaconic acid. Reaction of rosin with citraconic anhydride was studied at 140–180 °С within 0.5–8 hrs in presence of catalytic amounts of H2SO4, MgCl2, AlCl3, FeCl3and new citraconopimaric adducts containing up to ~70 % of citraconopimaric acid as a mixture of two С15–CH3and С16–CH3isomers in equimolar ratio. The highest content of С15–CH3isomer of citraconopimaric acid (35.5–36.0 %) in the adducts was reached within 4–8 hrs at 180 °С in presence of 1–2 mass. % H2SO4. The reaction of rosin with citraconic anhydride at 140–160 °С leads to the formation of adduct containing up to 30–50 % of citraconopimaric acid isomers. The synthesized adducts may be used for production of composite materials for different applications (adhesives, polymer composite additives including rubber blends for tire production, components of grease-cooling liquids).