Benzyl mercaptan
[CAS# 100-53-8]

Identification

• Classification: Flavors and spices >> Synthetic spice >> Thiol perfume
• Name: Benzyl mercaptan
• Synonyms: alpha-Toluenethiol; Benzenemethanethiol; Thiobenzyl alcohol; Toluene-a-thiol
• Molecular Formula: C₇H₈S
• Molecular Weight: 124.20
• CAS Registry Number: 100-53-8
• EC Number: 202-862-5
• FEMA: 2147
• SMILES: C1=CC=C(C=C1)CS

Properties

• Density: 1.058
• Melting point: -29 °C
• Boiling point: 195 °C (10 torr)
• Refractive index: 1.574-1.576
• Flash point: 70 °C

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H319
• Safety Statements: P264-P264+P265-P270-P280-P301+P317-P305+P351+P338-P330-P337+P317-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Eye irritation	Eye Irrit.	2	H319
Acute toxicity	Acute Tox.	2	H330
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Skin irritation	Skin Irrit.	2	H315
Flammable liquids	Flam. Liq.	4	H227

Discovery and Applications

Benzyl mercaptan (also known as benzyl mercaptan or phenylmethyl mercaptan) is an organosulfur compound with a strong, unpleasant odor. This colorless to pale yellow liquid is widely used in applications ranging from flavoring to chemical synthesis. It consists of a benzyl group (C₆H₅CH₂-) and a thiol group (-SH) and is a clear, colorless to pale yellow liquid with a pungent, characteristic thiol odor.

Benzyl mercaptan was first synthesized in the late 19th century during research on thiol compounds, which have a distinctive odor and reactivity, and are obtained by reacting benzyl chloride with sodium hydrosulfide. Since its discovery, benzyl mercaptan has been studied for its chemical reactivity and potential applications in various industries.

Benzyl mercaptan is used as a trace flavoring agent to impart a characteristic salty and oniony flavor to foods. Its strong odor means it must be used with caution. It plays an important role in complex flavor profiles, especially in savory sauces, dressings, and condiments. Despite its strong odor, it can be used in fragrance formulations to add depth and complexity, and is often used in trace amounts to create unique scents in perfumes and scented products.

Benzyl mercaptan is a valuable intermediate in the synthesis of pharmaceuticals, agrochemicals, and specialty chemicals. Its reactivity with a variety of functional groups makes it useful in the manufacture of sulfur-containing compounds, which are important in drug development and chemical manufacturing. Benzyl mercaptan acts as a ligand in coordination chemistry, binding to metal ions to form complexes. These complexes are intensively studied for their catalytic properties and potential in materials science and catalysis.

Benzyl mercaptan is used as a chain transfer agent in the polymerization of certain plastics and resins. By controlling the molecular weight and distribution of the polymer, benzyl mercaptan can tailor the mechanical and thermal properties of the final material to make it suitable for specific applications. Benzyl mercaptan is used as a stabilizer in certain polymer formulations to increase the life and durability of the product by preventing degradation.

Benzyl mercaptan is used as an analytical reagent in biological and chemical research to detect and quantify thiol groups in proteins and other biomolecules. Its ability to react with disulfide bonds makes it useful for studying the structure and function of proteins. Benzyl mercaptan is used as a model compound to study the reactivity and mechanisms of thiol groups in biological systems, aiding in the understanding of enzyme function and redox processes.

Benzyl mercaptan is sometimes added as an odorant to natural gas and other odorless gases to detect leaks. Its strong and recognizable odor provides a warning signal for the presence of the gas, improving safety in residential and industrial environments. Benzyl mercaptan is used to develop methods to remove sulfur-containing compounds from industrial emissions and wastewaters. Its reactivity with other sulfur-containing compounds aids in the development of environmental remediation and pollution control strategies.

References

2023. Structure-Property Relationship Analysis of D-Penicillamine-Derived β-Polythioesters with Varied Alkyl Side Groups. Chinese Journal of Polymer Science, 41(11).
DOI: 10.1007/s10118-023-3001-8

2024. CuO Decorated Magnetic Reduced Graphene Oxide Catalyzed Cross-Dehydrogenative Coupling of Thiols and Alkylbenzenes. Catalysis Letters, 154(8).
DOI: 10.1007/s10562-024-04761-4

2024. Volatile metabolomics and metagenomics reveal the effects of lactic acid bacteria on alfalfa silage quality, microbial communities, and volatile organic compounds. Communications Biology, 7(1).
DOI: 10.1038/s42003-024-07083-8