Selective purification of mono-terpenes for removal of oxygen containing species

1. A process for purifying monoterpenes, comprising the steps of:

providing a monoterpene comprising alpha terpinene of about 90% or greater purity and comprising an oxygen-containing impurity compound selected from the group consisting of 1,8-cineole, 1,4,-cineole, and mixtures thereof;

providing an activated silica gel preparative chromatographic column;

contacting the monoterpene with the column, wherein the oxygen-containing impurity compounds are retained on the column;

recovering monterpenes depleted of oxygen-containing impurity compounds from the column by applying a pressure above atmospheric from a gas source; and

removing the oxygen-containing impurity compounds by contacting the column with an alcohol.

2. The process of claim 1 wherein the contacting step is discontinued when the oxygen-containing impurity compound is no longer retained on the column.

3. The process of claim 1 wherein the monoterpene further comprises one or more monoterpenes selected from the group consisting of: d-limonene, alpha phellandrene, para cymene, and mixtures thereof.

4. The process of claim 1 wherein the oxygen-containing impurity compounds further comprises one or more of linalool, octanol, and water.

5. The process of claim 1 wherein the contacting step is conducted at ambient temperature, and pressures between 0-100 psi.

6. The process of claim 1 wherein the monoterpenes recovered from the column have an oxygen-containing impurity compound content of no more than 10 ppm and a water content of no more than 40 ppm.

7. The process of claim 1 wherein the alcohol is selected from the group consisting of: ethanol, propanol, isopropanol, and mixtures thereof.

8. The process of claim 1 wherein the oxygen-containing impurity compound is 1,8-cineole.

9. A process for purifying monoterpenes comprising the steps of:

providing a monoterpene comprising alpha terpinene of about 90% or greater purity, wherein the neat monoterpene comprises at least one oxygen-containing impurity compound selected from the group consisting of: 1,8-cineole, 1,4-cineole, and mixtures thereof;

providing an activated silica gel preparative chromatographic column;

contacting the monterpene containing oxygen-containing impurity compounds with the column, wherein the oxygen-containing impurity compounds are retained on the column;

recovering monoterpenes depleted of oxygen-containing impurity compounds from the column by applying a pressure above atmospheric from a gas source;

discontinuing the contacting when the oxygen-containing impurity compounds are no longer retained on the compound; and

removing the oxygen-containing impurity compounds by contacting the column with an alcohol and recovering a mixture of the alcohol and the retained oxygen-containing impurity compounds from the column.

10. A process for purifying monoterpenes comprising the steps of:

providing a monterpene comprising alpha terpinene of about 90% or greater purity, wherein the neat monoterpene comprises at least one oxygen-containing impurity compound selected from the group consisting of 1,8-cineole, 1,4-cineole, and mixtures thereof in a monoterpene source container;

providing an activated silica gel preparative chromatographic column connected to the monoterpene source container;

dispensing the monoterpene from the monoterpene source container using an inert pressurizing gas to contact the monoterpene on the column, wherein the oxygen-containing impurity compounds are retained on the column;

recovering monoterpenes depleted of oxygen-containing impurity compounds from column by applying a pressure above atmospheric from a gas source;

discontinuing the contacting when the oxygen-containing impurity compounds are no longer retained on the column; and

removing the oxygen-containing impurity compounds by dispensing an alcohol from an alcohol source container and contacting the column with the alcohol and recovering a mixture of the alcohol and the column-retained oxygen-containing impurity compounds from the column.

11. A process for purifying alpha terpinene comprising the steps of:

providing alpha terpinene of about 90% or greater purity comprising 1,8-cineole;

providing an activated silica gel preparative chromatographic column;

contacting the alpha terpinene containing 1,8-cineole with the column, wherein the 1,8-cineole on the column is retained on the column;

recovering alpha terpinene depleted of the 1,8-cineole from the column by applying a pressure above atmospheric from a gas source;

discontinuing the contacting when the 1,8-cineole is no longer retained on the column; and

removing the 1,8-cineole by contacting the column with an alcohol and recovering a mixture of the alcohol and the 1,8-cineole from the column.