Methyl isothiocyanate

From Wikipedia, the free encyclopedia
  (Redirected from Methylisothiocyanate)
Jump to: navigation, search
Methyl isothiocyanate
Methyl isothiocyanate.png Methyl-isothiocyanate-3D-vdW.png
Identifiers
CAS number 556-61-6 YesY
PubChem 11167
ChemSpider 10694 YesY
KEGG C18587 N
ChEBI CHEBI:78337 N
ChEMBL CHEMBL396000 YesY
Jmol-3D images Image 1
Properties
Molecular formula C2H3NS
Molar mass 73.12 g mol−1
Appearance colourless solid
Density 1.07 g cm–3
Melting point 31 °C (88 °F; 304 K)
Boiling point 117 °C (243 °F; 390 K)
Solubility in water 8.2g/L
Hazards
MSDS ACC# 07204
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g., calcium Special hazards (white): no codeNFPA 704 four-colored diamond
Structure
Dipole moment 3.528 D
Related compounds
Related compounds Methyl isocyanate
Methyl thiocyanate
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
Infobox references

Methyl isothiocyanate is the organosulfur compound with the formula CH3N=C=S. This low melting colorless solid is a powerful lachrymator. As a precursor to a variety of valuable bioactive compounds, it is the most important organic isothiocyanate in industry.[1]

Synthesis[edit]

It is prepared industrially by two routes. Annual production in 1993 was estimated to be 4M kg. The main method involves the thermal rearrangement of methyl thiocyanate:[1]

CH3S-C≡N → CH3N=C=S

It is also prepared via with the reaction of methylamine with carbon disulfide followed by oxidation of the resulting dithiocarbamate with hydrogen peroxide. A related method is useful to prepare this compound in the laboratory.[2]

MITC forms naturally upon the enzymatic degradation of glucocapparin, a modified sugar found in capers.

Reactions[edit]

A characteristic reaction is with amines to give methyl thioureas:

CH3NCS + R2NH → R2NC(S)NHCH3
Reaction scheme: MITC and secondary amine react to form a thiourea

Other nucleophiles add similarly.

Applications[edit]

Solutions of MITC are used in agriculture as soil fumigants, mainly for protection against fungi and nematodes.

MITC is a building block for the synthesis of 1,3,4-thiadiazoles, which are heterocyclic compounds used as herbicides. Commercial products include "Spike", "Ustilan," and "Erbotan." Well known pharmaceuticals prepared using MITC include Zantac and Tagamet.

Safety[edit]

MITC is a dangerous lachrymator as well as being poisonous.

References[edit]

  1. ^ a b Romanowski, F.; Klenk, H. (2005), "Thiocyanates and Isothiocyanates, Organic", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, doi:10.1002/14356007.a26_749 
  2. ^ Moore, M. L.; Crossley, F. S. (1941), "Methyl Isothiocyanate", Org. Synth. 21: 81 ; Coll. Vol. 3: 599