In this project, we have investigated a new approach for the production of Menthol. Menthol is, owing to its uniquely fresh taste and smell, arguably one of the world’s most popular organic compounds. It is added to a broad range of products which are part of our daily lives, including such as toothpastes, shower gels or cooling ointments. It is either extracted from natural sources such as peppermint oil or more usually, to meet high demand, produced synthetically.
The largest commercial production, using the so-called BASF method, is based on a series of chemical reactions which turn bulk chemicals into menthol. The process involves the late-stage conversion of citronellal into isopulegol, which is then converted into menthol. Despite being highly efficient, the process is costly and often relying on heavy metal catalysts for key steps (such as the conversion of isopulegol to menthol), can result in product contamination and environmental degradation.
The focus of our work in NEUTRAMENTH was in determining whether it is possible to directly prepare Menthol, in a single synthetic step, from Citronellal. The project has its genesis in unrelated observations made during the ERC Consolidator Grant VINCAT of the PI, where an unexpected observation in the reactivity of vinyl cations suggested a pathway for the sought after transformation.
In NEUTRAMENTH, we therefore set out to further optimize the process, demonstrating its technical feasibility and implementation, while conducting market analysis and developing an Intellectual Property Rights strategy.
We have validated the initial hypothesis and were able to demonstrate feasibility for the proposed transformation. The project has also resulted in a number of unexpected, yet potentially valuable routes to related substances. These substances should be further developed in future projects.
The results of this project could be a game-changer for an entire industry; the potential opening of downstream possibilities and applications to new classes of terpenes is an entire new page in itself.
