Acetone cyanohydrin

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Acetone cyanohydrin
Skeletal formula of acetone cyanohydrin
Ball and stick model of acetone cyanohydrin
Spacefill model of acetone cyanohydrin
Names
IUPAC name
2-Hydroxy-2-methylpropanenitrile[2]
Other names
Cyanohydrin-2-propanone[1]

α-Hydroxyisobutyronitrile[1]
2-Hydroxy-2-methyl-propionitrile[1]

2-Methylactonitrile[1]
Identifiers
3D model (Jmol)
3DMet B00479
605391
ChEBI
ChemSpider
DrugBank
ECHA InfoCard 100.000.828
EC Number 200-909-4
KEGG
MeSH acetone+cyanohydrin
RTECS number OD9275000
UN number 1541
Properties
C4H7NO
Molar mass 85.11 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
−121.7–−120.1 kJ mol−1
−2.4514–−2.4498 MJ mol−1
Hazards
Safety data sheet fishersci.com
GHS pictograms The skull-and-crossbones pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The environment pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word DANGER
H300, H310, H330, H410
P260, P273, P280, P284, P301+310
Very Toxic T+ Dangerous for the Environment (Nature) N
R-phrases R26/27/28, R50
S-phrases (S1/2), S27, S45
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 4: Very short exposure could cause death or major residual injury. E.g., VX gas Reactivity code 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g., phosphorus Special hazards (white): no codeNFPA 704 four-colored diamond
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)
US health exposure limits (NIOSH):
PEL (Permissible)
none[1]
REL (Recommended)
C 1 ppm (4 mg/m3) [15-minute][1]
IDLH (Immediate danger)
N.D.[1]
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).
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Infobox references

Acetone cyanohydrin (ACH) is an organic compound used in the production of methyl methacrylate, the monomer of the transparent plastic polymethyl methacrylate (PMMA), also known as acrylic. It is extremely toxic.

Preparation[edit]

The compound is generated as part of the acetone cyanohydrin route to methyl methacrylate. It is treated with sulfuric acid to give the sulfate ester of the methacrylamide, methanolysis of which gives ammonium bisulfate and MMA.[3] In the laboratory, this compound may be prepared by reacting sodium cyanide with acetone, followed by acidification:[4]

Synthesis of acetone cyanohydrin.png

Considering the high toxicity of acetone cyanohydrin, a safer lab scale production has been developed using microreactor technology.[5] Alternatively, a simplified procedure involves the action of sodium or potassium cyanide on the sodium bisulfite adduct of acetone prepared in situ. This gives a less pure product that is suitable for most syntheses.[6]

Natural occurrence[edit]

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

Safety[edit]

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

References[edit]

  1. ^ a b c d e f g "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. ^ Bauer, Jr., William (2002), "Methacrylic Acid and Derivatives", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, doi:10.1002/14356007.a16_441, ISBN 3-527-30673-0 .
  4. ^ Cox, R. F. B.; Stormont, R. T. "Acetone Cyanohydrin". Org. Synth. ; Coll. Vol., 2, p. 7 
  5. ^ Heugebaert, Thomas S. A.; Roman, Bart I.; De Blieck, Ann; Stevens, Christian V. (2010-08-11). "A safe production method for acetone cyanohydrin". Tetrahedron Letters. 51 (32): 4189–4191. doi:10.1016/j.tetlet.2010.06.004. 
  6. ^ Wagner, E. C.; Baizer, Manuel. "5,5-Dimethylhydantoin". Org. Synth. ; Coll. Vol., 3, p. 323 

External links[edit]