Acetone cyanohydrin

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Acetone cyanohydrin
Skeletal formula of acetone cyanohydrin
Ball and stick model of acetone cyanohydrin
Ball and stick model of acetone cyanohydrin
Spacefill model of acetone cyanohydrin
Spacefill model of acetone cyanohydrin
Names
Preferred IUPAC name
2-Hydroxy-2-methylpropanenitrile[2]
Other names
  • Cyanohydrin-2-propanone[1]
  • α-Hydroxyisobutyronitrile[1]
  • 2-Hydroxy-2-methyl-propionitrile[1]
Identifiers
3D model (
JSmol
)
3DMet
605391
ChEBI
ChemSpider
DrugBank
ECHA InfoCard
100.000.828 Edit this at Wikidata
EC Number
  • 200-909-4
KEGG
MeSH acetone+cyanohydrin
RTECS number
  • OD9275000
UNII
UN number 1541
  • InChI=1S/C4H7NO/c1-4(2,6)3-5/h6H,1-2H3 checkY
    Key: MWFMGBPGAXYFAR-UHFFFAOYSA-N checkY
  • CC(C)(O)C#N
Properties
C4H7NO
Molar mass 85.106 g·mol−1
Appearance Colourless liquid
Density 932 mg·mL−1
Melting point −21.2 °C; −6.3 °F; 251.9 K
Boiling point 95 °C; 203 °F; 368 K
Vapor pressure 2 kPa (at 20 °C)
1.399
Thermochemistry
Std enthalpy of
formation
fH298)
−121.7 to −120.1 kJ·mol−1
Std enthalpy of
combustion
cH298)
−2.4514 to −2.4498 MJ·mol−1
Hazards
GHS labelling:
GHS06: Toxic GHS09: Environmental hazard
Danger
H300, H310, H330, H410
P260, P273, P280, P284, P301+P310
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 4: Very short exposure could cause death or major residual injury. E.g. VX gasFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazards (white): no code
4
1
2
Flash point 75 °C (167 °F; 348 K)
Explosive limits
2.25–11%
Lethal dose or concentration (LD, LC):
  • 15.8 mg·kg−1 (dermal, rabbit)
  • 18.65 mg·kg−1 (oral, rat)
NIOSH (US health exposure limits):
PEL (Permissible)
None[1]
REL (Recommended)
C 1 ppm (4 mg·m−3) [15-minute][1]
IDLH
(Immediate danger)
N.D.[1]
Safety data sheet (SDS) fishersci.com
Related compounds
Related alkanenitriles
Related compounds
DBNPA
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Acetone cyanohydrin (ACH) is an

polymethyl methacrylate (PMMA), also known as acrylic. It liberates hydrogen cyanide
easily, so it is used as a source of such. For this reason, this cyanohydrin is also highly toxic.

Preparation

In the laboratory, this compound may be prepared by treating sodium cyanide with acetone, followed by acidification:[3]

Considering the high toxicity of acetone cyanohydrin, a lab scale production has been developed using a

bisulfite adduct of acetone prepared in situ. This gives a less pure product, one that is nonetheless suitable for most syntheses.[5]

Reactions

Acetone cyanohydrin is an intermediate en route to

methanolysis of which gives ammonium bisulfate and methyl methacrylate.[7]

It is used as a surrogate in place of HCN, as illustrated by its use as a precursor to lithium cyanide:[8]

(CH3)2C(OH)CN + LiH → (CH3)2CO + LiCN + H2

In transhydrocyanation, an equivalent of HCN is transferred from acetone cyanohydrin to another acceptor, with acetone as byproduct. The transfer is an equilibrium process, initiated by base. The reaction can be driven by trapping reactions or by the use of a superior HCN acceptor, such as an aldehyde.[9] In the hydrocyanation reaction of butadiene, the transfer is irreversible.[10]

Natural occurrence

Cassava tubers contain linamarin, a glucoside of acetohydrin, and the enzyme linamarase for hydrolysing the glucoside. Crushing the tubers releases these compounds and produces acetone cyanohydrin.

Safety

Acetone cyanohydrin is classified as an

extremely hazardous substance in the US Emergency Planning and Community Right-to-Know Act and carries an RCRA P069 waste code. The principal hazards of acetone cyanohydrin arise from its ready decomposition on contact with water, which releases highly toxic hydrogen cyanide
.

References

  1. ^ a b c d e f NIOSH Pocket Guide to Chemical Hazards. "#0005". National Institute for Occupational Safety and Health (NIOSH).
  2. ^ "acetone cyanohydrin - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 16 September 2004. Identification. Retrieved 8 June 2012.
  3. ^ Cox, R. F. B.; Stormont, R. T. "Acetone Cyanohydrin". Organic Syntheses; Collected Volumes, vol. 2, p. 7.
  4. .
  5. ^ Wagner, E. C.; Baizer, Manuel. "5,5-Dimethylhydantoin". Organic Syntheses; Collected Volumes, vol. 3, p. 323.
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External links