The thermal isomerization of myrcene (1), dihydramyrcene (2), and alloacimene (3) in the presence of ZnCl₂-KCl-NaCl fused salts (Chlorate fused salts) or NaNO₂-NaNO₃-KNO₃ fused salts (Nitrate fused salts) was carried out under different temperatures and the salt effect of the products was studied.
The results obtained are as follows : In the Chlorate fused salts, 1, 4-p-menthadiene (4) and 1, 8-p-menthadiene (5) were obtained as the two main products from (1) and (3). In the Nitrate fused salts, 2, 4 (8) -p-menthadiene (7) (product ratio 60%) was obtained from (1). α- and β-Pyronenes (14) and (16) were obtained as the two main products from (3). Under particular conditions, the (14) and (16) ratio was 30 : 47. In both fused salts, α- and β-cyclodihydromyrcenes (11) and (12) were obtained as two main products from (2) at the highest conversion (product ratio 62%, 45%) among the isomerization products.