{ "id": "epnbmsyjcr", "slug": "ammoxidation", "title": "Ammoxidation", "updated": "2026-10-25", "topic_path": [ { "id": "physical", "label": "Physical world and mathematics", "api_url": "https://www.edgepedia.org/api/v1/topics/physical" }, { "id": "physical.chemistry", "label": "Chemistry", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.chemistry" }, { "id": "physical.chemistry.methods", "label": "Chemical principles and methods", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.chemistry.methods" }, { "id": "physical.chemistry.methods.chemical-synthesis", "label": "Chemical synthesis", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.chemistry.methods.chemical-synthesis" }, { "id": "physical.chemistry.methods.chemical-synthesis.named-preparative-methods", "label": "Named synthetic methods", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.chemistry.methods.chemical-synthesis.named-preparative-methods" }, { "id": "physical.chemistry.methods.chemical-synthesis.named-preparative-methods.alpha-2-to-he", "label": "Titles 2 to He", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.chemistry.methods.chemical-synthesis.named-preparative-methods.alpha-2-to-he" } ], "geo": [ { "id": "geo.nongeo.t1800.physical.chemistry.methods.chemical-synthesis.named-preparative-methods", "label": "Non-geographic · 1800 to 1945: Named synthetic methods", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.chemistry.methods.chemical-synthesis.named-preparative-methods", "path": [ { "id": "geo.nongeo", "label": "Non-geographic", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo" }, { "id": "geo.nongeo.t1800", "label": "Non-geographic · 1800 to 1945", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800" }, { "id": "geo.nongeo.t1800.physical", "label": "Physical world and mathematics", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical" }, { "id": "geo.nongeo.t1800.physical.chemistry", "label": "Chemistry", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.chemistry" }, { "id": "geo.nongeo.t1800.physical.chemistry.methods", "label": "Chemical principles and methods", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.chemistry.methods" }, { "id": "geo.nongeo.t1800.physical.chemistry.methods.chemical-synthesis", "label": "Chemical synthesis", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.chemistry.methods.chemical-synthesis" }, { "id": "geo.nongeo.t1800.physical.chemistry.methods.chemical-synthesis.named-preparative-methods", "label": "Named synthetic methods", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.chemistry.methods.chemical-synthesis.named-preparative-methods" } ] } ], "excerpt": "Ammoxidation is a gas-phase catalytic partial oxidation that converts methyl groups into nitrile groups using ammonia and oxygen over mixed metal oxide catalysts, used industrially to make acrylonitrile from propylene.", "snippet": "Ammoxidation is a gas-phase catalytic partial oxidation that converts methyl groups into nitrile groups using ammonia and oxygen over mixed metal oxide catalysts, used industrially to make acrylonitrile from propylene.", "node": "physical.chemistry.methods.chemical-synthesis.named-preparative-methods.alpha-2-to-he", "markdown": "# Ammoxidation\n\nAmmoxidation is a gas-phase catalytic partial oxidation that converts a methyl group (or an aldehyde or alcohol group) positioned alpha to double bonds in olefinic, aromatic, or heteroaromatic hydrocarbons into a nitrile group, using ammonia and oxygen over a mixed metal oxide catalyst.[1](https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/cctc.201000173) It is used in the production of large-scale chemicals such as acrylonitrile, made from propylene, ammonia, and air according to\n\nwith water as the stoichiometric coproduct.[2](https://www.sciencedirect.com/science/article/pii/S2667109323004050)\n\n| Key fact | Detail |\n|---|---|\n| Reaction type | Gas-phase partial oxidation inserting nitrogen into methyl groups alpha to C=C bonds, over supported transition metal oxides[1](https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/cctc.201000173) |\n| Principal product | Acrylonitrile from propylene; \\( \\mathrm{C_3H_6 + 1.5\\,O_2 + NH_3 \\rightarrow C_3H_3N + 3\\,H_2O} \\)[2](https://www.sciencedirect.com/science/article/pii/S2667109323004050) |\n| Scale | ~7 million metric tons of acrylonitrile per year worldwide (2018)[3](https://www.osti.gov/pages/biblio/2283176) |\n| Catalysts | Bismuth molybdates for propylene; Mo–V–Te/Sb–Nb and Sb–V oxides for propane[1](https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/cctc.201000173) • [2](https://www.sciencedirect.com/science/article/pii/S2667109323004050) |\n| Operating window | About 400–510 °C, roughly 0.5–2 bar (49–196 kPa), 1–15 s contact time[4](https://www.nsche.org/Journal/assets/JNSChE/2020%20Edition/Articles/DESIGN_OF_AMMOXIDATION_PROCESS_FOR_THE_PRODUC_4560.pdf) • [5](https://www.freepatentsonline.com/5235088.html) |\n| Industrial yield | ~85% acrylonitrile at nearly 100% one-pass propylene conversion; ~38.7% overall yield on propane[2](https://www.sciencedirect.com/science/article/pii/S2667109323004050) • [6](https://www.diquima.upm.es/old_diquima/docencia/tqindustrial/docs/acrilonitrilo.pdf) |\n| Byproducts | Hydrogen cyanide, acetonitrile, acrolein, CO and CO₂, nitrogen[7](https://www.osti.gov/biblio/1418290) • [6](https://www.diquima.upm.es/old_diquima/docencia/tqindustrial/docs/acrilonitrilo.pdf) |\n\n## How it works\n\nThe reaction follows a Mars–van Krevelen redox cycle: the hydrocarbon reacts with catalyst lattice oxygen, which abstracts hydrogen to form an allylic or benzylic intermediate, and the reduced surface is reoxidized by gas-phase oxygen. Nitrogen insertion is attributed to adsorbed N species, and the nitrile forms via an imine intermediate.[1](https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/cctc.201000173)\n\nA density functional theory study of propene over the (010) surface of \\( \\mathrm{Bi_2Mo_3O_{12}} \\) found that the rate-limiting step for both oxidation and ammoxidation is the initial hydrogen abstraction from the methyl group, with an apparent activation energy of 27.3 kcal/mol.[8](https://www.osti.gov/pages/biblio/1416914) The allyl species is stabilized as an allyl alkoxide, which can either undergo further hydrogen abstraction to acrolein or react with ammonia adsorbed on under-coordinated surface Bi³⁺ cations to form allylamine. Dehydrogenation of allylamine produces acrylonitrile, whereas reaction with additional adsorbed ammonia leads to acetonitrile and hydrogen cyanide.[8](https://www.osti.gov/pages/biblio/1416914)\n\nKinetics match this picture: propene consumption is first order in propene and zero order in ammonia (for \\( \\mathrm{NH_3/C_3H_6} \\) = 0–2) and oxygen (for \\( \\mathrm{O_2/C_3H_6} \\ge 1.5 \\)) partial pressures, with an activation energy of about 22 kcal/mol.[7](https://www.osti.gov/biblio/1418290)\n\n## How it is done\n\nPropylene, ammonia, and air are fed at controlled ratios into a fluidized-bed catalytic reactor at 400–510 °C and 49–196 kPa.[4](https://www.nsche.org/Journal/assets/JNSChE/2020%20Edition/Articles/DESIGN_OF_AMMOXIDATION_PROCESS_FOR_THE_PRODUC_4560.pdf) A multicomponent catalyst patent specifies 300–600 °C (especially 400–480 °C) and 0.1–50 s contact, delivering per-pass conversions to the nitrile product of 80 percent and above.[5](https://www.freepatentsonline.com/5235088.html) The fluidized bed is used because it removes the substantial heat released by the reaction.[9](https://www.acs.org/content/dam/acsorg/education/whatischemistry/landmarks/acrylonitrile/sohio-acrylonitrile-process-commemorative-booklet-2007.pdf)\n\nA propane-based design illustrates the full flowsheet: a fluidized-bed reactor with cooling surfaces generating 600 psia steam, operating at 500 °C and 30 psia at exit with a 5 s contact time and a C3H8:NH3:air molar feed ratio of 1.00:0.62:9.48.[6](https://www.diquima.upm.es/old_diquima/docencia/tqindustrial/docs/acrilonitrilo.pdf) Downstream, the reactor effluent is quenched and absorbed in water. Byproduct hydrogen cyanide is removed as gas or liquid, high-boiling carbonyl impurities are incinerated, and acrylonitrile is separated from acetonitrile by [extractive distillation](https://www.edgepedia.org/extractive-distillation) with water as solvent, which generates a heterogeneous azeotrope.[4](https://www.nsche.org/Journal/assets/JNSChE/2020%20Edition/Articles/DESIGN_OF_AMMOXIDATION_PROCESS_FOR_THE_PRODUC_4560.pdf) • [6](https://www.diquima.upm.es/old_diquima/docencia/tqindustrial/docs/acrilonitrilo.pdf)\n\n## Origin\n\nPropylene ammoxidation was not commercialized at that time.[2](https://www.sciencedirect.com/science/article/pii/S2667109323004050) [Commercialization](https://www.edgepedia.org/commercialization) came with the SOHIO Process employing the mixed metal oxide \\( \\mathrm{Bi_9PMo_{12}O_{52}/SiO_2} \\).[2](https://www.sciencedirect.com/science/article/pii/S2667109323004050) An ammoxidation experiment produced acrylonitrile in about 50 percent yield, with acetonitrile and hydrogen cyanide as co-products.[9](https://www.acs.org/content/dam/acsorg/education/whatischemistry/landmarks/acrylonitrile/sohio-acrylonitrile-process-commemorative-booklet-2007.pdf) Earlier work in the same program had shown that bismuth phosphomolybdate converted propylene to acrolein in yields of 40 percent or more in a single catalytic step, and among the bismuth, tin, and antimony salts of phosphomolybdic and molybdic acids, a bismuth phosphomolybdate was preferred and gave the best results.[9](https://www.acs.org/content/dam/acsorg/education/whatischemistry/landmarks/acrylonitrile/sohio-acrylonitrile-process-commemorative-booklet-2007.pdf) • [10](https://scholarship.libraries.rutgers.edu/view/pdfCoverPage?download=true&filePid=13643502280004646&instCode=01RUT_INST)\n\n## Variants\n\n**Propylene route.** Bismuth molybdate-based catalysts remain the industrial standard. Bismuth greatly enhances the ammoxidation reactivity of Mo-based oxide, raising conversion from about 5% to over 80%; a Bi-based catalyst without Mo mainly oxidizes propylene to carbon oxides, showing that Mo enables selective oxidation and inhibits deep oxidation.[2](https://www.sciencedirect.com/science/article/pii/S2667109323004050) Catalyst development raised acrylonitrile yield from about 50% on bismuth molybdate to over 80% on the latest catalysts containing more than 10 different metal elements, and a maximum acrylonitrile yield of about 85% at nearly 100% one-pass propylene conversion has held for decades of commercial operation.[2](https://www.sciencedirect.com/science/article/pii/S2667109323004050)\n\n**Propane route.** Direct ammoxidation of propane is harder because the C–H bond strength of an alkane is higher than that of the corresponding alkene; antimony–vanadium (Sb–V) mixed oxides are among the most interesting catalytic systems for paraffins.[11](https://www.ukm.my/mjas/v11_n1/25_433C5_IR_Iz_Anita-1.pdf) In the Mo–V–O family (Mo–V–O, Mo–V–Te–O, Mo–V–Sb–O, Mo–V–Te–Nb–O, Mo–V–Sb–Nb–O), Mo and V activate propane to propene, the rate-determining step; Te or Sb roughly doubles acrylonitrile selectivity and promotes propene-to-nitrile conversion, whereas catalysts lacking them promote destructive conversion to \\( \\mathrm{CO_x} \\); selectivity is further increased by the introduction of Nb to the Mo–V–Te–O and Mo–V–Sb–O catalysts.[12](https://pubs.acs.org/doi/abs/10.1021/ie0509286) Semi-commercial and pilot propane plants were built by BP (V(Al)SbO₄ rutile antimonate), [Mitsubishi](https://www.edgepedia.org/mitsubishi) (Mo/V/Nb/Te/O), and Asahi (Mo/V/Nb/Sb/O).[13](https://www.sciencedirect.com/science/article/abs/pii/S0926860X03003156) The overall reaction,\n\n\\( \\mathrm{C_3H_8 + NH_3 + 2\\,O_2 \\rightarrow C_3H_3N + 4\\,H_2O} \\), with \\( \\Delta H \\approx -151 \\) kcal/mol (about −632 kJ/mol) propane for gaseous acrylonitrile and water, and proceeds by prior dehydrogenation of propane to propylene.[12](https://pubs.acs.org/doi/abs/10.1021/ie0509286)\n\n**Aromatic route.** For toluene ammoxidation to benzonitrile, vanadium–phosphorous oxide (VPO) supported on mesoporous SBA-15, prepared by deposition–precipitation, outperforms unsupported VPO, with performance correlating with catalyst reducibility.[14](https://pubs.rsc.org/en/content/articlelanding/2023/nj/d3nj00818e)\n\n**Dynamic operation.** In reactor operation, forced dynamic operation, periodically switching between a phase containing all reactants and an \\( O_{2} \\)-only phase over an industrial bismuth molybdate catalyst, improved acrylonitrile yields versus steady state under certain conditions, with performance correlating with lattice oxygen availability.[3](https://www.osti.gov/pages/biblio/2283176)\n\n## Applications\n\nGlobal acrylonitrile capacity was about 8.24 mtpa in 2021, forecast to reach 10.74 mtpa in 2026, with the market volume estimated at about 8.79 million tons in 2026.[3](https://www.osti.gov/pages/biblio/2283176) • [15](https://www.researchandmarkets.com/reports/5714510/acrylonitrile-industry-installed-capacity-and) The same chemistry supplies fine-chemical intermediates such as nicotinonitrile for the agrochemical, health, and nutrition industries.[1](https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/cctc.201000173)\n\n## Limitations and alternatives\n\nThe main scope limitation is substrate functionality: only less-functionalized reactants convert cleanly, since more highly substituted molecules suffer side reactions.[1](https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/cctc.201000173) Before 1960, acrylonitrile was instead produced from highly poisonous hydrocyanic acid together with expensive ethylene oxide or acetylene, which significantly suppressed productivity.[2](https://www.sciencedirect.com/science/article/pii/S2667109323004050)\n\nA biomass-derived alternative reaches acrylonitrile molar yields exceeding 90% from ethyl 3-hydroxypropanoate via dehydration and nitrilation with ammonia over an inexpensive titanium dioxide solid acid catalyst, and a modeled integrated process achieves near-quantitative yields of 98 ± 2% from ethyl acrylate, higher than standard propylene ammoxidation; avoiding hydrogen cyanide as a byproduct also improves process safety.[16](https://www.science.org/doi/10.1126/science.aan1059) On the propane route, a recent Chinese patent claims Mo–V-based oxide catalysts with alkali or alkaline earth metals giving yields above 60% and selectivity above 80% at 400–500 °C and 0.1–0.5 MPa.[17](https://eureka.patsnap.com/patent/CN122255025A)\n\n## References\n\n1. [Heterogeneously Catalyzed Ammoxidation: A Valuable Tool for One-Step Synthesis of Nitriles](https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/cctc.201000173)\n2. [Review: Advances in the catalytic production of acrylonitrile (Chem Catalysis, 2024)](https://www.sciencedirect.com/science/article/pii/S2667109323004050)\n3. [Propene ammoxidation over an industrial bismuth molybdate-based catalyst using forced dynamic operation](https://www.osti.gov/pages/biblio/2283176)\n4. [Design of Ammoxidation Process for the Production of Acrylonitrile (Journal of the Nigerian Society of Chemical Engineers, 2020)](https://www.nsche.org/Journal/assets/JNSChE/2020%20Edition/Articles/DESIGN_OF_AMMOXIDATION_PROCESS_FOR_THE_PRODUC_4560.pdf)\n5. [Process and catalyst for propylene ammoxidation to acrylonitrile (US Patent 5,235,088, The Standard Oil Company)](https://www.freepatentsonline.com/5235088.html)\n6. [Acrylonitrile by the Ammoxidation of Propane (process design document, Universidad Politécnica de Madrid)](https://www.diquima.upm.es/old_diquima/docencia/tqindustrial/docs/acrilonitrilo.pdf)\n7. [The mechanism and kinetics of propene ammoxidation over α-bismuth molybdate](https://www.osti.gov/biblio/1418290)\n8. [A DFT Investigation of the Mechanism of Propene Ammoxidation over α-Bismuth Molybdate](https://www.osti.gov/pages/biblio/1416914)\n9. [The Sohio Acrylonitrile Process (ACS commemorative booklet, 2007)](https://www.acs.org/content/dam/acsorg/education/whatischemistry/landmarks/acrylonitrile/sohio-acrylonitrile-process-commemorative-booklet-2007.pdf)\n10. [Sohio patent document (Rutgers scholarship repository copy)](https://scholarship.libraries.rutgers.edu/view/pdfCoverPage?download=true&filePid=13643502280004646&instCode=01RUT_INST)\n11. [Effect of Vanadium and Titanium Substitution over an Antimony-Based Mixed Oxide Catalyst for Propane Ammoxidation to Acrylonitrile (Malaysian Journal of Analytical Sciences)](https://www.ukm.my/mjas/v11_n1/25_433C5_IR_Iz_Anita-1.pdf)\n12. [Comparative Study on the Catalytic Performance of Single-Phase Mo−V−O-Based Metal Oxide Catalysts in Propane Ammoxidation to Acrylonitrile (Ind. Eng. Chem. Res.)](https://pubs.acs.org/doi/abs/10.1021/ie0509286)\n13. [Cr/V/Sb mixed oxides, catalysts for the ammoxidation of propane to acrylonitrile: Part II (Applied Catalysis A: General, DOI 10.1016/S0926-860X(03)00315-6)](https://www.sciencedirect.com/science/article/abs/pii/S0926860X03003156)\n14. [Vanadium–phosphorous oxide supported on mesoporous SBA-15 catalysts for ammoxidation of toluene to benzonitrile (New Journal of Chemistry, RSC, 2023)](https://pubs.rsc.org/en/content/articlelanding/2023/nj/d3nj00818e)\n15. [Acrylonitrile Industry Installed Capacity and Capital Expenditure (CapEx) Forecast by Region and Countries including details of All Active Plants, Planned and Announced Projects, 2022-2026](https://www.researchandmarkets.com/reports/5714510/acrylonitrile-industry-installed-capacity-and)\n16. [Renewable acrylonitrile production (Science, DOI 10.1126/science.aan1059)](https://www.science.org/doi/10.1126/science.aan1059)\n17. [CN122255025A – A process for the production of acrylonitrile by propane ammoxidation](https://eureka.patsnap.com/patent/CN122255025A)\n\n---\n*Topic: Encyclopedia › Physical world and mathematics › Chemistry › Chemical principles and methods › Chemical synthesis › Named synthetic methods › Titles 2 to He*\n\n*Initially written Sep 29, 2026 · Edited: Oct 15, 2026; Oct 25, 2026*\n\n*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*\n\nLicense: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license\n", "same_as": [], "url": "https://www.edgepedia.org/ammoxidation", "markdown_url": "https://www.edgepedia.org/ammoxidation.md", "license": { "name": "Edgepedia Community License 1.0", "url": "https://www.edgepedia.org/edgepedia/license", "summary": "Free with credit, commercial use included. AI training is open to everyone. For other uses, organizations over USD 100M in revenue or 100M monthly users license separately.", "spdx": "LicenseRef-Edgepedia-Community-1.0" }, "credit": "\"Ammoxidation\", Edgepedia (EdgeChat), https://www.edgepedia.org/ammoxidation. Edgepedia Community License 1.0.", "credit_md": "\"[Ammoxidation](https://www.edgepedia.org/ammoxidation)\", Edgepedia (EdgeChat), [https://www.edgepedia.org/ammoxidation](https://www.edgepedia.org/ammoxidation). [Edgepedia Community License 1.0](https://www.edgepedia.org/edgepedia/license).", "credit_html": "\"Ammoxidation\", Edgepedia (EdgeChat), https://www.edgepedia.org/ammoxidation. Edgepedia Community License 1.0.", "speakable": "Ammoxidation is a gas-phase catalytic partial oxidation that converts methyl groups into nitrile groups using ammonia and oxygen over mixed metal oxide catalysts, used industrially to make acrylonitrile from propylene." }