Process for separating alpha-pinene from beta-pinene

Abstract

A process for effecting at least the partial resolution of a first pinene mixture containing alpha pinene and beta pinene is described comprising the sequential steps of (i) admixing diethylene glycol with said first pinene mixture of alpha pinene and beta pinene thus forming a second pinene mixture; (ii) subjecting the resulting second pinene mixture of alpha pinene, beta pinene and diethylene glycol to fractional azeotropic distillation yielding (A) a distillate which is a two liquid phase non-emulsified composition the first phase of which is the lower phase and which consists essentially of diethylene glycol and the second phase of which is the upper phase and which consists essentially of a third pinene mixture consisting essentially of alpha pinene and beta pinene, substantially richer in alpha pinene than said first pinene mixture and (B) a bottoms mixture, which is a two liquid phase, non-emulsified composition, the first phase of which is the lower phase and which consists essentially of diethylene glycol and the second phase of which is the upper phase and which consists essentially of alpha-pinene and beta-pinene substantially richer in beta-pinene than said first pinene mixture; and (iii) physically separating said first phase from said second phase by means of decantation. A preferred manner of carrying out such process comprises the sequential steps of (i) first removing, in the absence of azeotroping agent, by means of distillation a portion of the .alpha.-pinene from the first pinene mixture whereby 80% of the .alpha.-pinene is removed from the first pinene mixture of .alpha.-pinene and beta pinene and whereby said first pinene mixture is enriched in concentration of beta pinene, thereby forming a second pinene mixture; (ii) admixing diethylene glycol with the resulting second pinene mixture of alpha pinene and beta pinene to form a third pinene mixture; (iii) subjecting the resulting third pinene mixture of alpha pinene, beta pinene and diethylene glycol to fractional azeotropic distillation yielding (A) a distillate which is a two liquid phase non-emulsified composition; the first phase of which is a lower phase and which consists essentially of diethylene glycol and the second phase of which is the upper phase and which consists essentially of a fourth pinene mixture consisting essentially of alpha pinene and beta pinene substantially richer in alpha pinene than said second pinene mixture and (B) a bottoms mixture, which is a two liquid phase, non-emulsified composition, the first phase of which is the lower phase and which consists essentially of diethylene glycol and the second phase of which is the upper phase and which consists essentially of alpha-pinene and beta-pinene substantially richer in beta-pinene than said first pinene mixture; and (iv) physically separating said first phase from said second phase by decantation.