Levomenthol is an organic compound derived from menthol, primarily used for its cooling and analgesic properties.

The name describes the structure of the molecule:

• Levo indicates that the compound is the levorotatory (i.e., rotating polarized light to the left) form of menthol.
• menthol is a natural alcohol found in peppermint oil.

Chemical Industrial Synthesis Process

• Synthesis of Menthone: Menthone, a natural compound extracted from mint oil, is the primary precursor in the synthesis of levomenthol. Menthone can be isolated or synthesized from other natural raw materials.
• Hydrogenation of Menthone: The key process in the production of levomenthol is the hydrogenation of menthone. This chemical reaction reduces menthone to levomenthol, using a hydrogenation catalyst such as nickel or palladium.
• Purification: After the hydrogenation reaction, the product is purified to remove impurities and byproducts of the reaction. This can be done through fractional distillation, crystallization, or chromatography.
• Quality Control: The purified levomenthol undergoes various quality tests to confirm its purity, chemical structure, and physical properties. These tests may include IR spectroscopy, NMR, and gas chromatography.
• Stabilization: To ensure the stability of levomenthol during transportation and storage, stabilizers may be added. This step is crucial to maintaining the effectiveness of levomenthol in various product formulations.

Form and Color

 Commonly appears in a solid crystalline form, colorless or white.

What it is used for and where

It artificially imparts the taste and scent of mint and is produced as an oil, alcohol or extract.

Much used in cigarettes, baked goods, pharmaceuticals, beverages, chewing gum, toothpastes, mouthwashes.

Cosmetics

It is a restricted ingredient as III/338 a Relevant Item in the Annexes of the European Cosmetics Regulation 1223/2009. Substance or ingredient reported:     Menthol; dl-menthol; l-menthol; d-menthol. The presence of the substance shall be indicated in the list of ingredients referred to in Article 19(1), point (g), when its concentration exceeds: — 0,001 % in leave-on products — 0,01 % in rinse-off products.

• Denaturant. It makes cosmetics unpalatable. It is sometimes added to cosmetics containing ethyl alcohol to make it unsuitable for ingestion. The ionic or polar molecules of this ingredient included in formulations that interact with protein groups, modulate the properties of the solution to suit specific needs.
• Fragrance. It plays a decisive and important role in the formulation of cosmetic products as it provides the possibility of enhancing, masking or adding fragrance to the final product, increasing its marketability. It is able to create a perceptible pleasant odour, masking a bad smell. The consumer always expects to find a pleasant or distinctive scent in a cosmetic product. 
• Refreshing. This ingredient is included in cosmetic products to provide a refreshing or toning sensation to the skin and can also help relieve irritation or redness.
• Soothing. Ingredient with the task of restoring moisture to the skin, helping in the healing process of irritation, inflammation and skin disorders.

Commercial applications:

Pharmaceutical and Cosmetic Industry: Menthol is widely used in pharmaceuticals, cosmetics, and personal care products such as creams, ointments, lip balms, toothpaste, and fresh breath products.

Oral Care Products: Contributes to the fresh feeling in toothpaste and mouthwashes.

Aromatherapy: Menthol is also used in aromatherapy for its relaxing and calming properties.

Menthol studies

• Molecular Formula: C₁₀H₂₀O
• Molecular Weight: 156.269 g/mol
• CAS: 89-78-1  491-01-0  1490-04-6  15356-70-4
• EC Number: 201-939-0  216-074-4  239-388-3  207-723-2
• FEMA Number: 2665
• PubChem Substance ID 57651951
• MDL number: MFCD00001484
• Beilstein Registry Number: 3194263

Synonyms:

• Menthol, (1alpha,2beta,5alpha)-Isomer
• dl-Menthol
• Cyclohexanol, 5-methyl-2-(1-methylethyl)-
• 2-Isopropyl-5-methylcyclohexanol
• Racementhol
• (+/-)-Menthol
• 5-Methyl-2-(1-methylethyl)cyclohexanol
• 3-p-Menthol
• 2-Isopropyl-5-methylcyclohexan-1-ol
• 1-methyl-4-isopropyl-3-hydroxycyclohexane
• 4-Isopropyl-1-methylcyclohexan-3-ol
• 3-Hydroxy-p-menthane
• (1S, 2S, 5R)-(+)-Neomenthol
• Cyclohexanol, 5-methyl-2-(1-methylethyl)-, [1S-(1.alpha.,2.alpha.,5.beta.)]-
• 5-methyl-2-(propan-2-yl)cyclohexanol
• Cyclohexanol, 5-methyl-2-(1-methylethyl)-, (1R,2S,5R)-rel-
• 5-methyl-2-propan-2-ylcyclohexan-1-ol
• Cyclohexanol, 5-methyl-2-(1-methylethyl)-, (1.alpha.,2.beta.,5.alp