Malononitrile

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Malononitrile
Skeletal formula of malononitrile Malondinitrile Structural Formula V1.svg
Skeletal formula of malononitrile
Ball-and-stick model Malononitrile-3D-balls.png
Ball-and-stick model
Space-filling model Malononitrile-3D-spacefill.png
Space-filling model
Names
IUPAC name
Malononitrile [1]
Preferred IUPAC name
Propanedinitrile [1]
Other names
Malonodinitrile, Cyanoacetonitrile, Dicyanomethane, Malonic dinitrile [2]
Identifiers
3D model (JSmol)
773697
ChEBI
ChemSpider
ECHA InfoCard 100.003.368 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 203-703-2
1303
MeSH dicyanmethane
PubChem CID
RTECS number
  • OO3150000
UNII
UN number 2647
  • InChI=1S/C3H2N2/c4-2-1-3-5/h1H2 Yes check.svgY
    Key: CUONGYYJJVDODC-UHFFFAOYSA-N Yes check.svgY
  • N#CCC#N
Properties
CH2(CN)2
Molar mass 66.063 g·mol−1
AppearanceColourless or white solid [2]
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) [2] [ clarification needed ]
Thermochemistry
110.29 J K−1 mol−1
Std molar
entropy (S⦵298)
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:
GHS-pictogram-skull.svg GHS-pictogram-pollu.svg
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 [2]
REL (Recommended)
TWA 3 ppm (8 mg/m3) [2]
IDLH (Immediate danger)
N.D. [2]
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.

Contents

Preparation and reactions

It can be prepared by dehydration of cyanoacetamide. [3] This method is mainly practiced in China where environmental rules are lax.[ citation needed ] 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-Gas-Synthese.svg
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]

Interstellar occurrence

Due to its permanent dipole moment (i.e., 3.735 ± 0.017 D), [7] malononitrile was detected in spectral emissions coming from interstellar cloud TMC-1 through the QUIJOTE line survey conducted with the Yebes 40 m radio telescope. [8] [9]

References

  1. 1 2 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.
  2. 1 2 3 4 5 6 NIOSH Pocket Guide to Chemical Hazards. "#0378". National Institute for Occupational Safety and Health (NIOSH).
  3. ↑ Surrey, Alexander (1945). "Malononitrile". Organic Syntheses. 25: 63–64. doi:10.15227/orgsyn.025.0063.
  4. 1 2 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.
  7. ↑ Hirota, Eizi; Morino, Yonezo (1960-02-01). "Microwave Spectrum of Malononitrile, CH2(CN)2. I. The Molecular Structure in the Ground Vibrational State". Bulletin of the Chemical Society of Japan. 33 (2): 158–162. doi:10.1246/bcsj.33.158. ISSN   0009-2673.
  8. ↑ Agúndez, M.; Bermúdez, C.; Cabezas, C.; Molpeceres, G.; Endo, Y.; Marcelino, N.; Tercero, B.; Guillemin, J.-C.; de Vicente, P.; Cernicharo, J. (August 2, 2024). "The rich interstellar reservoir of dinitriles: Detection of malononitrile and maleonitrile in TMC-1". Astronomy & Astrophysics. 688: L31. arXiv: 2408.02843 . doi:10.1051/0004-6361/202451525. ISSN   0004-6361 . Retrieved January 7, 2025.
  9. ↑ Victoria Corless (2024-11-12). "Scientists found 'nitriles' in an interstellar cloud — here's why that could be huge". Space.com. Retrieved 2025-01-07.
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