Adiponitrile

Adiponitrile is the organic compound with the formula (CH2)4(CN)2. This dinitrile, a viscous, colourless liquid, is an important precursor to the polymer nylon 66. In 2005, about one million tonnes were produced.[4]

Adiponitrile
Structural formula of adiponitrile
Ball-and-stick model of the adiponitrile molecule
Names
Preferred IUPAC name
Hexanedinitrile[1]
Other names
  • Adipic acid dinitrile
  • Adipic acid nitrile
  • Adipyldinitrile
  • 1,4-Dicyanobutane
  • Hexanedioic acid dinitrile
  • Nitrile adipico
  • Tetramethylene cyanide
  • Tetramethylene dicyanide
Identifiers
3D model (JSmol)
1740005
ChemSpider
ECHA InfoCard 100.003.543 Edit this at Wikidata
EC Number
  • 203-896-3
MeSH adiponitrile
RTECS number
  • AV2625000
UNII
UN number 2205
  • InChI=1S/C6H8N2/c7-5-3-1-2-4-6-8/h1-4H2 checkY
    Key: BTGRAWJCKBQKAO-UHFFFAOYSA-N checkY
  • N#CCCCCC#N
Properties
C6H8N2
Molar mass 108.144 g·mol−1
Appearance Colourless liquid
Density 951 mg mL−1
Melting point 1 to 3 °C; 34 to 37 °F; 274 to 276 K
Boiling point 295.1 °C; 563.1 °F; 568.2 K
50 g/L (20 °C)
Vapor pressure 300 mPa (at 20 °C)
1.438
Thermochemistry
84.5–85.3 kJ mol−1
Hazards
GHS pictograms GHS06: Toxic
GHS Signal word Danger
H301, H315, H319, H330, H335
P260, P284, P301+310, P305+351+338, P310
NFPA 704 (fire diamond)
4
2
0
Flash point 93 °C; 199 °F; 366 K (open cup)[2]
550 °C (1,022 °F; 823 K)
Explosive limits 1.7–4.99%
Lethal dose or concentration (LD, LC):
155 mg kg−1 (oral, rat)
NIOSH (US health exposure limits):
PEL (Permissible)
none[2]
REL (Recommended)
TWA 4 ppm (18 mg/m3)[2]
IDLH (Immediate danger)
N.D.[2]
Related compounds
Related alkanenitriles
Glutaronitrile
Related compounds
hexanedioic acid
hexanedihydrazide
hexanedioyl dichloride
hexanediamide
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

ProductionEdit

Early routesEdit

Because of the industrial value of adiponitrile, many methods have been developed for its synthesis. Early industrial routes started from furfural and later by the chlorination of butadiene to give 1,4-dichloro-2-butene, which with sodium cyanide, converts to 3-hexenedinitrile, which in turn can be hydrogenated to adiponitrile:[4]

ClCH2CH=CHCH2Cl + 2 NaCN → NCCH2CH=CHCH2CN + 2 NaCl
NCCH2CH=CHCH2CN + H2 → NC(CH2)4CN

Adiponitrile has also been produced from adipic acid, by dehydration of the diamide, but this route is rarely employed.

Modern routesEdit

The majority of adiponitrile is prepared by the nickel-catalysed hydrocyanation of butadiene, as discovered at DuPont, pioneered by Drinkard. The net reaction is:

CH2=CHCH=CH2 + 2 HCN → NC(CH2)4CN

 

The process involves several stages, the first of which involves monohydrocyanation (addition of one molecule of HCN), affording isomers of pentenenitriles as well as 2- and 3-methylbutenenitriles. These unsaturated nitriles are subsequently isomerized to the 3-and 4-pentenenitriles. In the final stage, these pentenenitriles are subjected to a second hydrocyanation, in an anti-Markovnikov sense, to produce adiponitrile.[4]

3-pentenenitrile, formed in the first hydrocyanation, can undergo alkene metathesis to give dicyanobutenes, which are readily hydrogenated as described above. A useful byproduct of the production of adiponitrile is 2-methylglutaronitrile.

The other major industrial route involves hydrodimerization, starting from acrylonitrile:[5][6]

2 CH2=CHCN + 2 e + 2 H+ → NCCH2CH2CH2CH2CN

The electrolytic coupling of acrylonitrile was discovered at Monsanto Company.

ApplicationsEdit

Almost all adiponitrile is hydrogenated to 1,6-diaminohexane for the production of nylon:[7]

NC(CH2)4CN + 4 H2 → H2N(CH2)6NH2

Like other nitriles, adiponitrile is susceptible to hydrolysis. The resulting adipic acid however is more cheaply prepared by other routes.

ProductionEdit

In 2018 there was about 1.5 million tons of capacity. The main producers of adiponitrile are: [8] [9]

  • Ascend: Decatur,AL 400kt, being expanded to 580kt by 2022
  • Invista: Victoria,TX and Orange,TX.
  • Invista and BASFjv 'Butachimie': Chalampé (France). Production to be increased from 100kt in 2020 to 600kt.
  • Asahi Kasei

BASF closed the 128kt ADN plant at Seal Sands in 2009 [10]

In 2015, Shandong Runxing New Material 100kt plant suffered an explosion and was not reopened.[8] In 2022, Invista plans to open a 300-400kt plant in Shanghai[11]

SafetyEdit

The LD50 for adiponitrile is 300 mg/kg for oral ingestion by rats.[4]

In 1990, ACGIH adopted a time weighted average Threshold Limit Value of 2ppm for work related skin exposure.[12]

The NIOSH recommended skin exposure limit for a work related time weighted average concentration is 4ppm (18 mg/m3).[13]

It is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.[14]

ReferencesEdit

  1. ^ "adiponitrile - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 26 March 2005. Identification. Retrieved 15 June 2012.
  2. ^ a b c d NIOSH Pocket Guide to Chemical Hazards. "#0015". National Institute for Occupational Safety and Health (NIOSH).
  3. ^ "Archived copy". Archived from the original on 2015-04-02. Retrieved 2015-03-26.CS1 maint: archived copy as title (link)
  4. ^ a b c d M. T. Musser, "Adipic Acid" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. doi:10.1002/14356007.a01_269
  5. ^ Cardoso, D. S.; Šljukić, B.; Santos, D. M.; Sequeira, C. A. (July 17, 2017). "Organic Electrosynthesis: From Laboratorial Practice to Industrial Applications". Organic Process Research & Development. 21 (9): 1213–1226. doi:10.1021/acs.oprd.7b00004.
  6. ^ Baizer, Manuel M. (1964). "Electrolytic Reductive Coupling". Journal of the Electrochemical Society. 111 (2): 215. doi:10.1149/1.2426086.
  7. ^ Robert A. Smiley "Hexamethylenediamine" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. doi:10.1002/14356007.a12_629
  8. ^ a b Alexander, Tullo (7 Oct 2018). "The chemical industry is bracing for a nylon 6,6 shortage". cen.acs.org. 96 (40). Retrieved 2 March 2021.
  9. ^ "Ascend Finalizes $175 Million ADN Project in Alabama | CHEManager". www.chemanager-online.com. Retrieved 2 March 2021.
  10. ^ Gale, Lindsay (1 April 2009). "End of the line for Seal Sands". KHL Group. Retrieved 2 March 2021.
  11. ^ "INVISTA China ADN project receives final construction permit". invista.com. Retrieved 2 March 2021.
  12. ^ 2009 TLVs and BEIs, American Conference of Governmental Industrial Hygienists, Signature Publications, page 11 of 254.
  13. ^ NIOSH Pocket Guide NIOSH Publication 2005-149; September 2005
  14. ^ "40 C.F.R.: Appendix A to Part 355—The List of Extremely Hazardous Substances and Their Threshold Planning Quantities" (PDF) (July 1, 2008 ed.). Government Printing Office. Archived from the original (PDF) on February 25, 2012. Retrieved October 29, 2011. Cite journal requires |journal= (help)

External linksEdit