Smoking Tobacco Product Having Menthyl Keto Ester Additive

What is this patent about?

'319 is related to the field of flavored tobacco products, specifically addressing the problem of menthol instability and uneven delivery in cigarettes. The background acknowledges the increasing use of menthol as a tobacco additive but highlights issues such as menthol's volatility leading to contamination and inconsistent smoker experience.

The underlying idea behind '319 is to use menthyl keto esters as a menthol delivery mechanism. Instead of directly adding menthol, which is volatile, the invention uses a chemical compound that releases menthol during smoking. This compound is formed by combining menthol with a keto acid, creating a more stable and controlled release of the desired cooling sensation.

The claims of '319 focus on a smoking tobacco product incorporating an aliphatic keto acid ester of menthol. This includes variations in the keto acid component (beta, gamma, or delta) and the source of menthol (natural, synthetic, or mixtures). The key is the presence of this specific chemical compound within the tobacco product.

In practice, the menthyl keto ester is prepared by reacting a keto acid (like acetoacetic acid, levulinic acid, or 7-acetylbutyric acid) with menthol, often using a catalyst and azeotropic distillation to remove water. The resulting ester is then incorporated into the tobacco, typically by dissolving it in a solvent like ethanol and spraying the solution onto the cured tobacco. During smoking, the heat causes the ester to break down, releasing menthol and providing a more consistent and pleasant cooling effect.

This approach differs from simply adding menthol directly to tobacco because the ester form is less volatile, reducing contamination and extending shelf life. Furthermore, the chemical structure of the ester allows for a more controlled release of menthol during combustion, leading to a more uniform and desirable smoking experience. The use of different keto acids also allows for fine-tuning the flavor profile and aroma characteristics of the tobacco product.