Aroma
In spite of its apparent power and pungency, allyl isothiocyanate can be tolerated in surprisingly high concentration as a flavor chemical. However, the pungency is perceptible down to a level of 1-3 ppm in aqueous solution.
Used quite extensively in flavor compositions, particularly along with vinegar (pickled products). Also in meat and spice flavors. Concentration in pickled products may be as high as 80 ppm.
Chemical Properties
Allyl Isothiocyanate is the main component of mustard oil (>95%). It is a highly flammable, colorless to pale yellow, oily liquid with a typical mustard odor. Exposure to air might cause it to darken. It has a pungent, irritating smell and a bitter taste that can cause lacrimatory. It can be synthesized by reacting allyl chloride with alkaline-earth or alkali rhodanides.
Occurrence
In the essential oil from seeds of Brassica nigra Koch, Brassica juncea Hook. and Thoms., and Thlaspi
arvense; in the essential oil from roots of Cochlearia armoracia; in the seeds and roots of Alliaria officinalis; in onion juice; and
in the seeds of various Cruciferae. Reported found in pineapple (Anans comoscus), raw cabbage, cooked cabbage, sauerkraut, milk,
heated beans, horseradish (Armoracia lapathifolia), raw cauliflower, Brussels sprouts, turnip, Chinese cabbage, wasabi (Japanese
horseradish) (Wasabi japonica).
Uses
Allyl isothiocyanate, also known as mustard oil, is a synthetic flavoring agent that is used as an artificial oil of mustard and as an imitation horseradish flavor with application in condiments, meats, and pickles at 87 ppm. It has additional applications as an antiseptic, antiamebic, manufacture of flavors and war gas.
Preparation
By distillation of sodium thiocyanate and allyl chloride
Definition
ChEBI: Allyl isothiocyanate is an isothiocyanate with the formula CH2=CHCH2N=C=S. A colorless oil with boiling point 152℃, it is responsible for the pungent taste of mustard, horseradish, and wasabi. It has a role as a lachrymator, a metabolite, an antimicrobial agent, an apoptosis inducer and an antineoplastic agent. It is an isothiocyanate and an alkenyl isothiocyanate.
Production Methods
Producted from Allyl iodide and Potassium sulfocyanide. Allyl isothiocyanate is the chief component
of the volatile oil of black Mustard seed, and
can be isolated by enzymatic breakdown of the
glycoside in the seed.
General Description
A colorless to pale-yellow oily liquid with an irritating odor. Flash point 135°F. Boiling point 300°F. Poisonous by ingestion and skin absorption. Emits toxic fumes when heated to high temperature. Insoluble in water and slightly denser than water. Hence sinks in water. Used to make other chemicals and as a fumigant. It should be stored in glass containers.
Air & Water Reactions
Flammable. Insoluble in water.
Reactivity Profile
A routine preparation by interaction of allyl chloride and sodium thiocyanate in an autoclave at 5.5 bar exploded violently at the end of the reaction. Peroxides were not present or involved and no other cause could be found, but extensive decomposition occurred when allyl isothiocyanate was heated to 250°C. in glass ampoules [Ind. Eng. Chem. 1941:19 1408].
Hazard
Extremely penetrating, pungent and stinging
odor. This chemical is a powerful Iachrymator,
and inhalation of its vapors may cause serious
damage to human lungs. The liquid and its
vapors produce blisters on the human skin.
A few grams may kill a man, if the oil is taken
internally.
Health Hazard
TOXIC; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance may cause severe injury, burns or death. Bromoacetates and chloroacetates are extremely irritating/lachrymators. Reaction with water or moist air will release toxic, corrosive or flammable gases. Reaction with water may generate much heat that will increase the concentration of fumes in the air. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.
Fire Hazard
HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors form explosive mixtures with air: indoors, outdoors and sewers explosion hazards. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapors may travel to source of ignition and flash back. Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff. Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated or if contaminated with water.
Contact allergens
Allyl isothiocyanate is generated by enzymatic hydrolysis
of the glucoside sinigrin, present in Cruciferae-
Brassicaceae, mainly the oil from black mustard seed
(Brassica nigra Koch). It may induce irritant and
sometimes allergic contact dermatitis, mimicking the
“tulip finger” dermatitis.
Anticancer Research
This compound was tested on Ehrlich ascites tumor cells transplanted in Swissalbino mice using HEK293 cells as control. There was a significantly reduced ascitessecretion and tumor cell proliferation. Also the vascular endothelial growth factorexpression was inhibited. The apoptosis was induced in tumor cells, and cellcycle was arrested at G1 phase (Ichwan et al. 2014).
Safety Profile
Suspected carcinogen with experimental neoplastigenic and tumorigenic data. Poison by ingestion, skin contact, intravenous, subcutaneous, and intraperitoneal routes. Experimental teratogenic and reproductive effects. An eye irritant. An allergen. May cause contact dermatitis. Mutation data reported. A flammable liquid. Highly reactive. When heated to decomposition (above 250') or on contact with acid or acid fumes it emits highly toxic fumes of CN-, SO,, and NOx. To fight fire, use foam, CO2, dry chemical. See also ALLYL COMPOUNDS and ESTERS.
Potential Exposure
Used in fumigants, veterinary drugs, ointments and counter irritants, mustard plasters, and as a flavoring agent.
Shipping
UN1545 Allyl isothiocyanate, stabilized, Hazard class: 6.1; Labels: 6.1-Poison Inhalation Hazard, 3 flammable liquids.
Purification Methods
Fractionate the isothiocyanate using an efficient column, preferably in a vacuum. It is a yellow pungent, irritating and TOXIC (suspected CARCINOGEN) liquid. Store it in a sealed tube under N2. The N'-benzylthiourea derivative has m 94.5o (from aqueous EtOH) [Weller et al. J Am Chem Soc 74 1104 1952]. [Beilstein 4 IV 1081.]
Incompatibilities
Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides, alcohols, amines
