isopropyl isothiocyanate

Isopropyl isothiocyanate, also known by its preferred name 2-isothiocyanatopropane, is a small organosulfur molecule characterized by the molecular formula C₄H₇NS. It appears as a clear liquid notable for its intense alliaceous scent resembling pungent mustard or horseradish. This compound is classified as an isothiocyanate ester and shares close chemical relation with other naturally occurring mustard oils. Common synonyms include propan-2-isothiocyanate and isothiocyanic acid isopropyl ester. It can be referenced in chemical databases such as PubChem (CID 75263). Isopropyl isothiocyanate is typically obtained from or identified in extracts of cruciferous plants, where it contributes to their characteristic sharp aroma and flavor profile.

Isopropyl isothiocyanate occurs naturally in various members of the Brassicaceae family, including brussel sprouts, Chinese cabbage, wasabi, horseradish, and mustard greens. These plants produce this compound as part of their defense mechanism and contribute to their distinctive pungency. In the food industry, isopropyl isothiocyanate is primarily used as a flavoring agent to impart a sharp, mustard-like note in vegetable-based flavors and wasabi formulations. Regulatory evaluation by the Flavor and Extract Manufacturers Association (FEMA, US) has assigned it the number 4425, recognizing its use within established flavoring parameters. Its potent odor profile makes it valuable in recreating or enhancing alliaceous and mustard flavors in processed foods and condiments.

Isopropyl isothiocyanate is a volatile liquid displaying moderate polarity due to the isothiocyanate functional group. It has a molecular weight of approximately 101.17 g/mol and exhibits a boiling point range between 136 and 138 °C at standard atmospheric pressure (760 mm Hg). Its specific gravity ranges from 0.947 to 0.955 at 25 °C, while its refractive index varies between 1.489 and 1.497 at 20 °C. This compound has an estimated logP value near 2.0, indicating moderate lipophilicity, which influences its solubility and partitioning behavior. It is slightly soluble in water, with approximately 1508 mg/L solubility at 25 °C, but freely soluble in alcohols. The flash point is about 40 °C (104 °F), pointing to flammability considerations during handling. These properties affect its formulation, storage, and sensory delivery within flavor blends.

	2-isothiocyanatopropane
NIST Chemistry WebBook:	Search Inchi
Pubchem (cid):	75263
Pubchem (sid):	135031564
Pherobase:	View

(IUPAC):	Atomic Weights of the Elements 2011 (pdf)
Videos:	The Periodic Table of Videos
tgsc:	Atomic Weights use for this web site
(IUPAC):	Periodic Table of the Elements
FDA Substances Added to Food (formerly EAFUS):	View
CHEMBL:	View
HMDB (The Human Metabolome Database):	Search
FooDB:	FDB009653
Export Tariff Code:	2930.90.9190
VCF-Online:	VCF Volatile Compounds in Food
ChemSpider:	View

Safety information

Preferred SDS: View
European information :
Most important hazard(s):
Xn - Harmful.
R 10 - Flammable. R 23/24/25 - Toxic by inhalation, in contact with skin and if swallowed. R 36/37/38 - Irritating to eyes, respiratory system, and skin. S 02 - Keep out of the reach of children. S 16 - Keep away from sources of ignition - No Smoking. S 20/21 - When using do not eat, drink or smoke. S 23 - Do not breath vapour. S 24/25 - Avoid contact with skin and eyes. S 26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S 36/37/39 - Wear suitable clothing, gloves and eye/face protection. S 45 - In case of accident or if you feel unwell seek medical advice immediately.
Hazards identification
Classification of the substance or mixture
GHS Classification in accordance with 29 CFR 1910 (OSHA HCS)
None found.
GHS Label elements, including precautionary statements
Pictogram
Hazard statement(s)
None found.
Precautionary statement(s)
None found.
Oral/Parenteral Toxicity:
Not determined
Dermal Toxicity:
Not determined
Inhalation Toxicity:
Not determined

Safety in use information

Category:
flavoring agents
Recommendation for isopropyl isothiocyanate usage levels up to:
	not for fragrance use.
Use levels for FEMA GRAS flavoring substances on which the FEMA Expert Panel based its judgments that the substances are generally recognized as safe (GRAS).
The Expert Panel also publishes separate extensive reviews of scientific information on all FEMA GRAS flavoring substances and can be found at FEMA Flavor Ingredient Library
publication number: 23
Click here to view publication 23
		average usual ppm	average maximum ppm
baked goods:		2.00000	20.00000
beverages(nonalcoholic):		-	-
beverages(alcoholic):		-	-
breakfast cereal:		-	-
cheese:		0.50000	5.00000
chewing gum:		-	-
condiments / relishes:		10.00000	50.00000
confectionery froastings:		-	-
egg products:		-	-
fats / oils:		1.00000	10.00000
fish products:		-	-
frozen dairy:		-	-
fruit ices:		-	-
gelatins / puddings:		-	-
granulated sugar:		-	-
gravies:		1.00000	10.00000
hard candy:		-	-
imitation dairy:		1.00000	10.00000
instant coffee / tea:		-	-
jams / jellies:		-	-
meat products:		0.50000	5.00000
milk products:		-	-
nut products:		-	-
other grains:		0.50000	5.00000
poultry:		-	-
processed fruits:		-	-
processed vegetables:		0.50000	5.00000
reconstituted vegetables:		0.50000	5.00000
seasonings / flavors:		5.00000	50.00000
snack foods:		1.00000	10.00000
soft candy:		-	-
soups:		1.00000	5.00000
sugar substitutes:		-	-
sweet sauces:		-	-

Safety references

EPI System: View

AIDS Citations:Search

Cancer Citations:Search

Toxicology Citations:Search

EPA ACToR:Toxicology Data

EPA Substance Registry Services (SRS):Registry

Laboratory Chemical Safety Summary :75263

National Institute of Allergy and Infectious Diseases:Data

WISER:UN 1992

WGK Germany:3

2-isothiocyanatopropane

Chemidplus:0002253738