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Malononitrile

Malononitrile
Skeletal formula of malononitrile
Ball-and-stick model
Ball-and-stick model
Space-filling model
Space-filling model
Names
IUPAC name
Malononitrile[2]
Preferred IUPAC name
Propanedinitrile[2]
Other names
Malonodinitrile, Cyanoacetonitrile, Dicyanomethane, Malonic dinitrile[1]
Identifiers
3D model (JSmol)
773697
ChEBI
ChemSpider
ECHA InfoCard 100.003.368 Edit this at Wikidata
EC Number
  • 203-703-2
1303
MeSH dicyanmethane
RTECS number
  • OO3150000
UNII
UN number 2647
  • InChI=1S/C3H2N2/c4-2-1-3-5/h1H2 checkY
    Key: CUONGYYJJVDODC-UHFFFAOYSA-N checkY
  • N#CCC#N
Properties
CH2(CN)2
Molar mass 66.063 g·mol−1
Appearance Colourless or white solid[1]
Density 1.049 g cm−3
Melting point 32 °C; 89 °F; 305 K
Boiling point 220.1 °C; 428.1 °F; 493.2 K
13% (20 °C)[1][clarification needed]
Thermochemistry
110.29 J K−1 mol−1
130.96 J K−1 mol−1
187.7 to 188.1 kJ mol−1
−1,654.0 to −1,654.4 kJ mol−1
Hazards
GHS labelling:
GHS06: Toxic GHS09: Environmental hazard
Danger
H301, H311, H331, H410
P261, P273, P280, P301+P310, P311
Flash point 86 °C (187 °F; 359 K)
Lethal dose or concentration (LD, LC):
  • 19 mg kg−1 (oral, mouse)
  • 350 mg kg−1 (dermal, rat)
NIOSH (US health exposure limits):
PEL (Permissible)
 none[1]
REL (Recommended)
 TWA 3 ppm (8 mg/m3)[1]
IDLH (Immediate danger)
 N.D.[1]
Related compounds
Related alkanenitriles
Related compounds
 Malonic acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Malononitrile is an organic compound nitrile with the formula CH2(CN)2. It is a colorless or white solid, although aged samples appear yellow or even brown. It is a widely used building block in organic synthesis.

Preparation and reactions

It can be prepared by dehydration of cyanoacetamide.[3] This method is mainly practiced in China where environmental rules are lax. Most commonly malononitrile is produced by the gas-phase reaction of acetonitrile and cyanogen chloride:[4]

NCCl + CH3CN → NCCH2CN + HCl

About 20,000,000 kg are produced annually (2007). Important outlets include the synthesis of thiamine, the drug triamterene and minoxidil, and the dyes disperse Yellow 90 and disperse Blue 354.[4]

Malononitrile is relatively acidic, with a pKa of 11 in water.[5] This allows it to be used in the Knoevenagel condensation, for example in the preparation of CS gas:

CS-chemical-synthesis
CS-chemical-synthesis

Despite its relative obscurity, Malononitrile is very useful in several reactions, the prime example being a suitable starting reagent for the Gewald reaction, where the nitrile condenses with a ketone or aldehyde in the presence of elemental sulfur and a base to produce a 2-aminothiophene.[6]

References

  1. ^ a b c d e f NIOSH Pocket Guide to Chemical Hazards. "#0378". National Institute for Occupational Safety and Health (NIOSH).
  2. ^ a b International Union of Pure and Applied Chemistry (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. p. 902. doi:10.1039/9781849733069. ISBN 978-0-85404-182-4.
  3. ^ Surrey, Alexander (1945). "Malononitrile". Organic Syntheses. 25: 63–64. doi:10.15227/orgsyn.025.0063.
  4. ^ a b Strittmatter, Harald; Hildbrand, Stefan; Pollak, Peter (2007). "Malonic Acid and Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a16_063.pub2. ISBN 978-3527306732.
  5. ^ Evans pKa table
  6. ^ Sabnis, R. W.; Rangnekar, D. W.; Sonawane, N. D. (1999). "2-Aminothiophenes By The Gewald Reaction". Journal of Heterocyclic Chemistry. 36 (2): 333–345. doi:10.1002/jhet.5570360203. Retrieved 2007-07-18.
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