Improvements in or relating to diels-alder reaction

摘要

Rosin is acid isomerized to a negative specific rotation [a ]D24 DEG of at least - 15 DEG before formation of a Diels-Alder product with maleic acid or anhydride. The rosin may be gum or wood rosin and the acid isomerization catalyst may be any strong acid, particularly sulphuric acid. Specification 633,332 is referred to.