Flavors & Fragrances
REACH
Butanethiol
CAS Number
109-79-5
EC Number
203-705-3
FEMA Number
FEMA 3478
What is Butanethiol?
Butanethiol (CAS 109-79-5), also known as n-butyl mercaptan, is a sulfur-containing organic compound used commercially as an odorant and flavoring agent. FEMA 3478.
Where is Butanethiol used?
- Oil and gas: stenching agent blended into natural gas and LPG, providing the characteristic warning odor
- Gas leak detection and trace-level sensory applications, enabled by its intensely low odor threshold
- Food and beverage: trace-level sulfurous, onion-like or savory top notes in processed flavors
- Flavor systems targeting meat, roasted and allium profiles
- Fragrance and flavor houses: reference standards and specialty aroma compositions requiring controlled sulfur character
- It is compliant with FEMA and relevant flavor safety standards.
Good to know: Its high odor intensity requires small containers and careful handling.
Commercial specifications
- Packaging from laboratory-scale quantities to drum volumes
Other Names (Synonyms)
n-Butyl mercaptan|n-Butanethiol|1-Mercaptobutane|1-Butanethiol|butane-1-thiol|BUTYL MERCAPTAN|Thiobutyl alcohol|n-Butyl thioalcohol
What are the physical properties of Butanethiol?
Melting Point -115.7 °C
Boiling Point 98.4 °C @ Press: 760 Torr
Density 0.8337 g/cm³ @ Temp: 20 °C
Flash Point 55 °F
Appearance colourless liquid
Color Colorless
Odor Strong skunk-like.
Form Liquid
Water Solubility 0.60 g/100 mL. Slightly soluble
Vapor Pressure 83 mm Hg ( 37.7 °C)
Refractive Index n 20/D 1.443(lit.)
Log P 2.28
How is Butanethiol classified and handled safely? Learn More
Danger
GHS02· Flammable GHS07· Irritant GHS08· Health Hazard
Hazard Statements
H225 Highly Flammable liquid and vapor
H302 Harmful if swallowed
H316 Causes mild skin irritation
H317 May cause an allergic skin reaction
Precautionary Statements
P203 Obtain, consult and follow expert instructions for use.
P210 Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
P233 Keep container tightly closed.
P240 Ground and bond container and receiving equipment.
Which trade and regulatory codes apply to Butanethiol?
HS Code 2930 90 98
UN Number 2347
ADR Class 3
Packing Group II
Storage Class 3 - Flammable liquids
WGK (Germany) 3