Chemistry:Acrylonitrile

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Acrylonitrile is an organic compound with the formula CH
2CHCN and the structure H
2C=CH–C≡N. It is a colorless, volatile liquid. It has a pungent odor of garlic or onions.[1] Its molecular structure consists of a vinyl group (–CH=CH
2) linked to a nitrile (–C≡N). It is an important monomer for the manufacture of useful plastics such as polyacrylonitrile. It is reactive and toxic at low doses.[2]

Acrylonitrile is one of the components of ABS plastic (acrylonitrile butadiene styrene).[3]

Structure and basic properties

Acrylonitrile is an organic compound with the formula CH
2CHCN and the structure H
2C=CH–C≡N. It is a colorless, volatile liquid although commercial samples can be yellow due to impurities. It has a pungent odor of garlic or onions.[1] Its molecular structure consists of a vinyl group (–CH=CH
2) linked to a nitrile (–C≡N). It is an important monomer for the manufacture of useful plastics such as polyacrylonitrile. It is reactive and toxic at low doses.[2]

Production

Acrylonitrile was first synthesized by the French chemist Charles Moureu in 1893.[4] 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,[2][5] rising to about 6 million tonnes by 2017.[6] Acetonitrile and hydrogen cyanide are significant byproducts that are recovered for sale.[2] In fact, the 2008–2009 acetonitrile shortage was caused by a decrease in demand for acrylonitrile.[7]

2 CH
3–CH=CH
2 + 2 NH
3 + 3 O
2 → 2 CH
2=CH–C≡N + 6 H
2O

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. One of the first useful catalysts was bismuth phosphomolybdate (Bi
9PMo
12O
52) supported on silica.[8] Further improvements have since been made.[2]

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.[9][6] The glycerol route begins with its dehydration to acrolein, which undergoes ammoxidation to give acrylonitrile.[10] The glutamic acid route employs oxidative decarboxylation to 3-cyanopropanoic acid, followed by a decarbonylation-elimination to acrylonitrile.[11] Of these, the glycerol route is broadly considered to be the most viable, although none of these green methods are commercially competitive.[9][10]

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[12][13] affords adiponitrile, used in the synthesis of certain nylons:

2 CH
2=CHCN + 2 e−
 + 2 H+
 → NCCH
2–CH
2–CH
2–CH
2CN

Acrylonitrile is also a precursor in the manufacture of acrylamide and acrylic acid.[2]

Synthesis of chemicals

Hydrogenation of acrylonitrile is one route to propionitrile. Hydrolysis with sulfuric acid gives acrylamide sulfate, CH=CHC(O)NH
2 · H
2SO
4. This salt can be converted to acrylamide with treatment with base or to methyl acrylate by treatment with methanol.[2]

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

YH + H
2C=CHCN → Y–CH
2–CH
2CN

Typical protic nucleophiles are alcohols, thiols, and especially amines.[14] When hydrogen cyanide is used the product is succinonitrile.[15]

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

Health effects

Acrylonitrile is toxic with LD50 = 81 mg/kg (rats). It undergoes explosive polymerization. The burning material releases fumes of hydrogen cyanide and oxides of nitrogen. It is classified as a Class 1 carcinogen (carcinogenic) by the International Agency for Research on Cancer (IARC),[16] and workers exposed to high levels of airborne acrylonitrile are diagnosed more frequently with lung cancer than the rest of the population.[17] Acrylonitrile is one of seven toxicants in cigarette smoke that are most associated with respiratory tract carcinogenesis.[18] The mechanism of action of acrylonitrile appears to involve oxidative stress and oxidative DNA damage.[19] Acrylonitrile increases cancer in high dose tests in male and female rats and mice[20] and induces apoptosis in human umbilical cord mesenchymal stem cells.[21]

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.[22] 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).[23] Repeated exposure causes skin sensitization and may cause central nervous system and liver damage.[22]

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.[23] Exposure can thus be detected via blood draws and urine sampling.[16]

In July 2024, the International Agency for Research on Cancer upgraded acrylonitrile's classification from 'possibly carcinogenic' to carcinogenic for humans. The Agency found sufficient evidence linking it to lung cancer.[24][25]

Use in plastic bottles

In June 1974 Coca-Cola introduced the acrylonitrile/styrene 32oz Easy‐Goer plastic bottle, offering energy savings during manufacture, increased durability, and weight savings over glass.[26] In March 1977 after a suit filed by the Natural Resources Defense Council the FDA rescinded approval of acrylonitrile bottles citing adverse effects on test animals.[27] Monsanto, Coca-Cola's bottle manufacturer refuted the decision, stating "repeated tests have demonstrated that there is no detectable migration of acrylonitrile into the bottle's content." After several appeals in court by September 1977 the FDA finalized their ban.[28][29]

Incidents

A large amount of acrylonitrile (approximately 6500 tons) leaked from an industrial polymer plant owned by Aksa Akrilik after the violent 17th August 1999 earthquake in Turkey. Over 5000 people were affected and the exposed animals had died.[30] The leak was only noticed by the company 8 hours after the incident. Healthcare workers did not know about the health effects of acrylonitrile and tried to treat the victims with painkillers and IV fluids.[31] One lawyer, Ayşe Akdemir, sued the company with 44 families as the plaintiffs.[31] Aksa Akrilik was sued by 200 residents who were affected by acrylonitrile.[32] An increase in cancer cases in the area was confirmed by the Turkish Medical Association,[32] as the cancer rate in the affected area has increased by 80%, from 1999 to April 2002.[31] In 2003, the owner of Aksa Akrilik died from lung cancer related to acrylonitrile exposure.[31] As of 2001, this is the largest known acrylonitrile leak.[30]

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.[33] Acrylonitrile is harmful to aquatic life.[22] Acrylonitrile has been detected in the atmosphere of Titan, a moon of Saturn.[34][35][36] 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.[34][35]

References

  1. ↑ 1.0 1.1 "Medical Management Guidelines for Acrylonitrile". Agency for Toxic Substances & Disease Registry. https://www.atsdr.cdc.gov/mmg/mmg.asp?id=443&tid=78. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 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. 
  3. ↑ Campo, E. Alfredo (2008-01-01), Campo, E. Alfredo, ed., "1 - Polymeric Materials and Properties", Selection of Polymeric Materials, Plastics Design Library (Norwich, NY: William Andrew Publishing): pp. 1–39, doi:10.1016/b978-081551551-7.50003-6, ISBN 978-0-8155-1551-7, https://www.sciencedirect.com/science/article/pii/B9780815515517500036, retrieved 2023-11-20 
  4. ↑
  5. ↑ "The Sohio Acrylonitrile Process". American Chemical Society National Historic Chemical Landmarks. http://portal.acs.org/portal/PublicWebSite/education/whatischemistry/landmarks/acrylonitrile/index.htm. 
  6. ↑ 6.0 6.1 Davey, Stephen G. (January 2018). "Sustainability: Sweet new route to acrylonitrile". Nature Reviews Chemistry 2 (1): 0110. doi:10.1038/s41570-017-0110. 
  7. ↑ Tullo, A. (2008). "A Solvent Dries Up". Chemical & Engineering News 86 (47): 27. doi:10.1021/cen-v086n047.p027. 
  8. ↑ 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. 
  9. ↑ 9.0 9.1 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. 
  10. ↑ 10.0 10.1 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. 
  11. ↑ 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. 
  12. ↑ Ellis, Paul G (1972). A radiation-chemical study of the hydrodimerisation of acrylonitrile. UK: Leeds University, Ph D thesis. 
  13. ↑ 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. doi:10.1039/f19797501050. 
  14. ↑ 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. 
  15. ↑ "Nitriles". Ullmann's Encyclopedia of Industrial Chemistry (7th ed.). http://www.mrw.interscience.wiley.com/emrw/9783527306732/ueic/article/a17_363/current/html?hd=All%2Csuccinonitrile. Retrieved 2007-09-10. 
  16. ↑ 16.0 16.1 Stayner, LT; Carreón-Valencia, T; Demers, PA; Fritz, JM; Sim, MR; Stewart, P; Tsuda, H; Cardenas, A et al. (2024). "Carcinogenicity of talc and acrylonitrile". Lancet Oncol 25: 962–963. doi:10.1016/s1470-2045(24)00384-x. PMID 38976996. 
  17. ↑ Acrylonitrile Fact Sheet (CAS No. 107-13-1). epa.gov
  18. ↑ Cunningham, FH; Fiebelkorn, S; Johnson, M; Meredith, C (Nov 2011). "A novel application of the Margin of Exposure approach: segregation of tobacco smoke toxicants". Food Chem Toxicol 49 (11): 2921–33. doi:10.1016/j.fct.2011.07.019. PMID 21802474. 
  19. ↑ Pu, X; Kamendulis, LM; Klaunig, JE (2009). "Acrylonitrile-induced oxidative stress and oxidative DNA damage in male Sprague-Dawley rats". Toxicol Sci 111 (1): 64–71. doi:10.1093/toxsci/kfp133. 
  20. ↑ "Acrylonitrile: Carcinogenic Potency Database".
  21. ↑ 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. 
  22. ↑ 22.0 22.1 22.2 "CDC – Acrylonitrile – International Chemical Safety Cards". NIOSH. https://www.cdc.gov/niosh/ipcsneng/neng0092.html. 
  23. ↑ 23.0 23.1 Acrylonitrile Fact Sheet: Support Document (CAS No. 107-13-1). epa.gov
  24. ↑ "WHO agency says talc is 'probably' cancer-causing". Philippine Daily Inquirer. July 6, 2024. https://globalnation.inquirer.net/241682/who-agency-says-talc-is-probably-cancer-causing. 
  25. ↑ Stayner, Leslie T; Carreón-Valencia, Tania; Demers, Paul A; Fritz, Jason M; Sim, Malcolm R; Stewart, Patricia; Tsuda, Hiroyuki; Cardenas, Andres et al. (July 5, 2024). "Carcinogenicity of talc and acrylonitrile". The Lancet Oncology 25 (8): 962–963. doi:10.1016/s1470-2045(24)00384-x. ISSN 1470-2045. PMID 38976996. 
  26. ↑ "Polyester Held a Winner Over Acrylonitrile in War About Soft-Drink Bottles". The New York Times. 1977-03-01. https://www.nytimes.com/1977/03/01/archives/polyester-held-a-winner-over-acrylonitrile-in-war-about-softdrink.html. 
  27. ↑ "Cancer Experts Warn of Dangers in Some Plastic Wrap Chemicals". The New York Times. 1977-02-23. https://www.nytimes.com/1977/02/23/archives/cancer-experts-warn-of-dangers-in-some-plastic-wrap-chemicals.html. 
  28. ↑ "Plastic Beverage Bottles Made From Acrylonitrile Are Banned by the F.D.A.". The New York Times. 1977-03-08. https://www.nytimes.com/1977/03/08/archives/plastic-beverage-bottles-made-from-acrylonitrile-are-banned-by-the.html. 
  29. ↑ "Monsanto Loses Plastic Bottle Fight". Chemical & Engineering News 55 (39): 6. 1977-09-26. doi:10.1021/cen-v055n039.p006. https://pubs.acs.org/doi/pdf/10.1021/cen-v055n039.p006. 
  30. ↑ 30.0 30.1 Nadi Bakırcı (2001). "ENDÜSTRİYEL BİR ÇEVRE FELAKETİ: AKRİLONİTRİL". Turkish Medical Association. https://www.ttb.org.tr/msg/dergi/ocak01/9.htm. 
  31. ↑ 31.0 31.1 31.2 31.3 Fatma Dalokay (30 November 2020). "17 Ağustos 1999 Depremi: Akrilonitril Zehirlenmesi". https://tabella.org/2020/11/30/17-agustos-1999-depremi-akrilonitril-zehirlenmesi/. 
  32. ↑ 32.0 32.1 "İSO'nun şaşırtan çevre ödülü Aksa'nın". 26 June 2005. https://mbigpara.hurriyet.com.tr/amp/haberler/iso-nun-sasirtan-cevre-odulu-aksa-nin/525904/. 
  33. ↑ 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. Bibcode: 1990JAWMA..40.1664G. 
  34. ↑ 34.0 34.1 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. 
  35. ↑ 35.0 35.1 Palmer, Maureen Y. (28 July 2017). "ALMA detection and astrobiological potential of vinyl cyanide on Titan". Science Advances 3 (7). doi:10.1126/sciadv.1700022. PMID 28782019. Bibcode: 2017SciA....3E0022P. 
  36. ↑ 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/. 



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