Chemistry:Acrylonitrile

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Acrylonitrile
Structural formula of acrylonitrile.svg
Acrylonitrile-2D-skeletal.svg
Acrylonitrile-3D-balls.png
Acrylonitrile-3D-vdW.png
Names
Preferred IUPAC name
Prop-2-enenitrile
Other names
Acrylonitrile
2-Propenenitrile
Cyanoethene
Vinyl cyanide (VCN)
Cyanoethylene[1]
Propenenitrile[1]
Vinyl nitrile
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
EC Number
  • 608-003-00-4
KEGG
RTECS number
  • AT5250000
UNII
UN number 1093
Properties
C3H3N
Molar mass 53.064 g·mol−1
Appearance Colourless liquid
Density 0.81 g/cm3
Melting point −84 °C (−119 °F; 189 K)
Boiling point 77 °C (171 °F; 350 K)
70 g/L
log P 0.19[2]
Vapor pressure 83 mmHg[1]
Hazards
Main hazards flammable
reactive
toxic
potential occupational carcinogen[1]
Safety data sheet ICSC 0092
NFPA 704 (fire diamond)
Flammability code 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g. gasolineHealth code 4: Very short exposure could cause death or major residual injury. E.g. VX gasReactivity code 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 codeNFPA 704 four-colored diamond
3
4
2
Flash point −1 °C; 30 °F; 272 K
471 °C (880 °F; 744 K)
Explosive limits 3–17%
Lethal dose or concentration (LD, LC):
500 ppm (rat, 4 h)
313 ppm (mouse, 4 h)
425 ppm (rat, 4 h)[3]
260 ppm (rabbit, 4 h)
575 ppm (guinea pig, 4 h)
636 ppm (rat, 4 h)
452 ppm (human, 1 h)[3]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 2 ppm C 10 ppm [15-minute] [skin][1]
REL (Recommended)
Ca TWA 1 ppm C 10 ppm [15-minute] [skin][1]
IDLH (Immediate danger)
85 ppm[1]
Related compounds
Related nitriles
acetonitrile
propionitrile
Related compounds
acrylic acid
acrolein
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☑Y verify (what is ☑Y☒N ?)
Infobox references

Acrylonitrile is an organic compound with the formula CH2CHCN. It is a colorless volatile liquid although commercial samples can be yellow due to impurities. It has a pungent odor of garlic or onions.[4] In terms of its molecular structure, it consists of a vinyl group linked to a nitrile. It is an important monomer for the manufacture of useful plastics such as polyacrylonitrile. It is reactive and toxic at low doses.[5] Acrylonitrile was first synthesized by the French chemist Charles Moureu (1863–1929) in 1893.[6]

Occurrence

Acrylonitrile is not naturally formed on Earth. It has been detected at the sub-ppm level at industrial sites. It persists in the air for up to a week. It decomposes by reacting with oxygen and hydroxyl radical to form formyl cyanide and formaldehyde.[7] Acrylonitrile is harmful to aquatic life.[8]

Acrylonitrile has been detected in the atmosphere of Titan, a moon of Saturn.[9][10][11] Computer simulations suggest that on Titan conditions exist such that the compound could form structures similar to cell membranes and vesicles on Earth, called azotosomes.[9][10]

Production

Acrylonitrile is produced by catalytic ammoxidation of propylene, also known as the SOHIO process. In 2002, world production capacity was estimated at 5 million tonnes per year,[5][12] rising to about 6 million tonnes by 2017.[13] Acetonitrile and hydrogen cyanide are significant byproducts that are recovered for sale.[5] In fact, the 2008–2009 acetonitrile shortage was caused by a decrease in demand for acrylonitrile.[14]

2 CH3−CH=CH2 + 2 NH3 + 3 O2 → 2 CH2=CH–C≡N + 6 H2O

In the SOHIO process, propylene, ammonia, and air (oxidizer) are passed through a fluidized bed reactor containing the catalyst at 400–510 °C and 50–200 kPag. The reactants pass through the reactor only once, before being quenched in aqueous sulfuric acid. Excess propylene, carbon monoxide, carbon dioxide, and dinitrogen that do not dissolve are vented directly to the atmosphere, or are incinerated. The aqueous solution consists of acrylonitrile, acetonitrile, hydrocyanic acid, and ammonium sulfate (from excess ammonia). A recovery column removes bulk water, and acrylonitrile and acetonitrile are separated by distillation. Historically, one of the first successful catalysts was bismuth phosphomolybdate (Bi9PMo12O52) supported on silica as a heterogeneous catalyst.[15] Further improvements have since been made.[5]

Alternative routes

Various green chemistry routes to acrylonitrile are being explored from renewable feedstocks, such as lignocellulosic biomass, glycerol (from biodiesel production), or glutamic acid (which can itself be produced from renewable feedstocks). The lignocellulosic route involves fermentation of the biomass to propionic acid and 3-hydroxypropionic acid, which are then converted to acrylonitrile by dehydration and ammoxidation.[16][13] The glycerol route begins with its dehydration to acrolein, which undergoes ammoxidation to give acrylonitrile.[17] The glutamic acid route employs oxidative decarboxylation to 3-cyanopropanoic acid, followed by a decarbonylation-elimination to acrylonitrile.[18] Of these, the glycerol route is broadly considered to be the most viable, although none of these green methods are commercially competitive.[16][17]

Uses

Acrylonitrile is used principally as a monomer to prepare polyacrylonitrile, a homopolymer, or several important copolymers, such as styrene-acrylonitrile (SAN), acrylonitrile butadiene styrene (ABS), acrylonitrile styrene acrylate (ASA), and other synthetic rubbers such as acrylonitrile butadiene (NBR). Hydrodimerization of acrylonitrile[19][20] affords adiponitrile, used in the synthesis of certain nylons:

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

Acrylonitrile is also a precursor in the industrial manufacture of acrylamide and acrylic acid.[5]

Synthesis of specialty chemicals

The reaction of acrylonitrile with protic nucleophiles is a common route to a variety of specialty chemicals. The process is called cyanoethylation:

[math]\displaystyle{ \mathrm{YH + H_2C{=}CH{-}CN \longrightarrow Y{-}CH_2{-}CH_2{-}CN} }[/math]

Typical protic nucleophiles are alcohols, thiols, and especially amines.[21]

Acrylonitrile and derivatives, such as 2-chloroacrylonitrile, are dienophiles in Diels–Alder reactions.

Health effects

Acrylonitrile is highly flammable and toxic at low doses. It undergoes explosive polymerization. The burning material releases fumes of hydrogen cyanide and oxides of nitrogen. It is classified as a Class 2B carcinogen (possibly carcinogenic) by the International Agency for Research on Cancer (IARC),[22] and workers exposed to high levels of airborne acrylonitrile are diagnosed more frequently with lung cancer than the rest of the population.[23] Acrylonitrile is one of seven toxicants in cigarette smoke that are most associated with respiratory tract carcinogenesis.[24] The mechanism of action of acrylonitrile appears to involve oxidative stress and oxidative DNA damage.[25] Acrylonitrile increases cancer in high dose tests in male and female rats and mice[26] and induces apoptosis in human umbilical cord mesenchymal stem cells.[27]

It evaporates quickly at room temperature (20 °C) to reach dangerous concentrations; skin irritation, respiratory irritation, and eye irritation are the immediate effects of this exposure.[8] Pathways of exposure for humans include emissions, auto exhaust, and cigarette smoke that can expose the human subject directly if they inhale or smoke. Routes of exposure include inhalation, oral, and to a certain extent dermal uptake (tested with volunteer humans and in rat studies).[28] Repeated exposure causes skin sensitization and may cause central nervous system and liver damage.[8]

There are two main excretion processes of acrylonitrile. The primary method is excretion in urine when acrylonitrile is metabolized by being directly conjugated to glutathione. The other method is when acrylonitrile is enzymatically converted into 2-cyanoethylene oxide which will produce cyanide end products that ultimately form thiocyanate, which is excreted via urine.[28] Exposure can thus be detected via blood draws and urine sampling.[22]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 NIOSH Pocket Guide to Chemical Hazards. "#0014". National Institute for Occupational Safety and Health (NIOSH). https://www.cdc.gov/niosh/npg/npgd0014.html. 
  2. "Acrylonitrile_msds". https://www.chemsrc.com/en/cas/107-13-1_1186893.html. 
  3. 3.0 3.1 "Acrylonitrile". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH). https://www.cdc.gov/niosh/idlh/107131.html. 
  4. "Medical Management Guidelines for Acrylonitrile". Agency for Toxic Substances & Disease Registry. https://www.atsdr.cdc.gov/mmg/mmg.asp?id=443&tid=78. 
  5. 5.0 5.1 5.2 5.3 5.4 Brazdil, James F.. "Ullmann's Encyclopedia of Industrial Chemistry". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a01_177.pub3. 
  6. Grosjean, Daniel (December 1990). "Atmospheric Chemistry of Toxic Contaminants. 3. Unsaturated Aliphatics: Acrolein, Acrylonitrile, Maleic Anhydride". Journal of the Air & Waste Management Association 40 (12): 1664–1669. doi:10.1080/10473289.1990.10466814. 
  7. 8.0 8.1 8.2 "CDC – Acrylonitrile – International Chemical Safety Cards". NIOSH. https://www.cdc.gov/niosh/ipcsneng/neng0092.html. 
  8. 9.0 9.1 Wall, Mike (28 July 2017). "Saturn Moon Titan Has Molecules That Could Help Make Cell Membranes". Space.com. https://www.space.com/37653-saturn-moon-titan-cell-membrane-molecules.html. 
  9. 10.0 10.1 Palmer, Maureen Y. (28 July 2017). "ALMA detection and astrobiological potential of vinyl cyanide on Titan". Science Advances 3 (7): e1700022. doi:10.1126/sciadv.1700022. PMID 28782019. Bibcode2017SciA....3E0022P. 
  10. Kaplan, Sarah (8 August 2017). "This weird moon of Saturn has some essential ingredients for life". The Washington Post. https://www.washingtonpost.com/news/speaking-of-science/wp/2017/08/08/this-weird-moon-of-saturn-has-some-essential-ingredients-for-life/. 
  11. "The Sohio Acrylonitrile Process". American Chemical Society National Historic Chemical Landmarks. http://portal.acs.org/portal/PublicWebSite/education/whatischemistry/landmarks/acrylonitrile/index.htm. 
  12. 13.0 13.1 Davey, Stephen G. (January 2018). "Sustainability: Sweet new route to acrylonitrile". Nature Reviews Chemistry 2 (1): 0110. doi:10.1038/s41570-017-0110. 
  13. Tullo, A. (2008). "A Solvent Dries Up". Chemical & Engineering News 86 (47): 27. doi:10.1021/cen-v086n047.p027. 
  14. Grasselli, Robert K. (2014). "Site isolation and phase cooperation: Two important concepts in selective oxidation catalysis: A retrospective" (in en). Catalysis Today 238: 10–27. doi:10.1016/j.cattod.2014.05.036. 
  15. 16.0 16.1 Grasselli, Robert K.; Trifirò, Ferruccio (2016). "Acrylonitrile from Biomass: Still Far from Being a Sustainable Process". Topics in Catalysis 59 (17–18): 1651–1658. doi:10.1007/s11244-016-0679-7. ISSN 1022-5528. 
  16. 17.0 17.1 Guerrero-Pérez, M. Olga; Bañares, Miguel A. (2015). "Metrics of acrylonitrile: From biomass vs. petrochemical route". Catalysis Today 239: 25–30. doi:10.1016/j.cattod.2013.12.046. ISSN 0920-5861. 
  17. Le Nôtre, Jérôme; Scott, Elinor L.; Franssen, Maurice C. R.; Sanders, Johan P. M. (2011). "Biobased synthesis of acrylonitrile from glutamic acid". Green Chemistry 13 (4): 807. doi:10.1039/c0gc00805b. ISSN 1463-9262. 
  18. Ellis, Paul G (1972). A radiation-chemical study of the hydrodimerisation of acrylonitrile. UK: Leeds University, Ph D thesis. 
  19. Buxton, George V.; Ellis, Paul G.; McKillop, Thomas F.W. (1979). "Pulse radiolysis study of acrylonitrile in aqueous solution". J. Chem. Soc., Faraday Trans. 1 75: 1050. 
  20. Eller, Karsten; Henkes, Erhard; Rossbacher, Roland; Höke, Hartmut (2000). "Ullmann's Encyclopedia of Industrial Chemistry". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a02_001. 
  21. 22.0 22.1 "Re-evaluation of Some Organic Chemicals, Hydrazine and Hydrogen Peroxide". IARC Monographs, Volume 71 (1999)
  22. Acrylonitrile Fact Sheet (CAS No. 107-13-1). epa.gov
  23. Cunningham FH, Fiebelkorn S, Johnson M, Meredith C. A novel application of the Margin of Exposure approach: segregation of tobacco smoke toxicants. Food Chem Toxicol. 2011 Nov;49(11):2921-33. doi: 10.1016/j.fct.2011.07.019. Epub 2011 Jul 23. PMID: 21802474
  24. Pu X, Kamendulis LM, Klaunig JE. Acrylonitrile-induced oxidative stress and oxidative DNA damage in male Sprague-Dawley rats. Toxicol Sci. 2009;111(1):64-71. doi:10.1093/toxsci/kfp133
  25. "Acrylonitrile: Carcinogenic Potency Database".
  26. Sun, X. (January 2014). "Cytotoxic effects of acrylonitrile on human umbilical cord mesenchymal stem cells in vitro". Molecular Medicine Reports 9 (1): 97–102. doi:10.3892/mmr.2013.1802. PMID 24248151. http://www.spandidos-publications.com/mmr/9/1/97. 
  27. 28.0 28.1 Acrylonitrile Fact Sheet: Support Document (CAS No. 107-13-1). epa.gov

External links