Tonalide
[CAS# 21145-77-7]

Identification

• Classification: Flavors and spices >> Synthetic spice >> Musk and macrocyclic spices >> Polycyclic musk
• Name: Tonalide
• Synonyms: Acetyl hexamethyl tetralin; 6-Acetyl-1,1,2,4,4,7-hexamethyltetralin; 1-(3,5,5,6,8,8-hexamethyl-6,7-dihydronaphthalen-2-yl)ethanone
• Molecular Formula: C₁₈H₂₆O
• Molecular Weight: 258.40
• CAS Registry Number: 21145-77-7 (1506-02-1)
• EC Number: 244-240-6;216-133-4
• SMILES: CC1CC(C2=C(C1(C)C)C=C(C(=C2)C(=O)C)C)(C)C

Properties

• Solubility: 0.2388 mg/L (25 °C water)
• Density: 0.9±0.1 g/cm³, Calc.^*
• Index of Refraction: 1.490, Calc.^*
• Melting point: 104.26 °C
• Boiling Point: 325.92 °C, 356.8±31.0 °C (760 mmHg), Calc.^*
• Flash Point: 149.9±19.8 °C, Calc.^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07;GHS09 Warning
• Risk Statements: H302-H400-H410
• Safety Statements: P264-P270-P273-P301+P317-P330-P391-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411

Discovery and Applications

Tonalide is a synthetic fragrance compound widely used in the fragrance and cosmetics industry. It is known chemically as 1,2,3,4,5,6-hexahydro-4,6,6,7,8,8-hexamethyl-2H-benzo[6]benzopyran-2-one, and it has a musky, floral odor. Tonalide belongs to a class of compounds called macrocyclic musks, which are known for their strong, long-lasting scent. It was first developed in the 1970s as part of efforts to create new, synthetic alternatives to natural musk, which is derived from the glands of musk deer and is now largely banned due to ethical and environmental concerns.

The discovery of Tonalide was a result of research into the synthesis of synthetic musks that could mimic the odor of natural musk but with more stable and reproducible properties. The synthetic musks were designed to address the high demand in the fragrance industry while avoiding the use of animal-derived materials. Tonalide, like other synthetic musks, is valued for its ability to provide a lasting fragrance in various products, including perfumes, deodorants, soaps, and lotions.

Tonalide is synthesized through a series of chemical reactions, beginning with the creation of a cyclic structure that resembles the natural musk compounds. The compound is characterized by a large, polycyclic structure, which is thought to contribute to its strong, persistent scent profile. It is typically used in small quantities due to its potency and stability, making it an efficient ingredient in the creation of complex fragrance formulations.

The primary application of Tonalide is in the fragrance industry, where it is incorporated into a wide range of personal care products, household goods, and perfumes. Its musky scent provides a base note in many fragrance compositions, often enhancing or complementing other floral, woody, or citrus notes. In addition to its use in cosmetics, Tonalide is also found in some cleaning products, air fresheners, and laundry detergents, where it helps to impart a long-lasting scent.

Despite its widespread use, Tonalide has come under scrutiny due to potential environmental concerns. It has been detected in water sources and is considered a persistent organic pollutant. In recent years, there has been increasing interest in alternatives to Tonalide and other synthetic musks that are more environmentally friendly and biodegradable.

In summary, Tonalide is a synthetic fragrance compound with widespread applications in the fragrance and cosmetics industries. Its development helped meet the demand for synthetic musks, offering a stable and effective alternative to natural musk. However, concerns about its environmental impact have prompted research into alternative, more sustainable options.

References

1986. Chemistry of odor stimuli. Cellular and Molecular Life Sciences, 42(3).
DOI: 10.1007/bf01942507

2023. Contaminants of emerging concern in urine: a review of analytical methods for determining diisocyanates, benzotriazoles, benzothiazoles, 4-methylbenzylidene camphor, isothiazolinones, fragrances, and non-phthalate plasticizers. Environmental Science and Pollution Research, 30(42).
DOI: 10.1007/s11356-023-29070-y

2023. Advances in Transformation Mechanism and Increased Adverse Effects of Pharmaceuticals and Personal Care Products During Environmental Geochemistry Processes. Reviews of Environmental Contamination and Toxicology, 262(1).
DOI: 10.1007/s44169-023-00048-8