Technology Type

Historical Development

Adiponitrile’s first industrial route (1950s–1960s) relied on multi-step chlorocyanation of butadiene; yielding admixtures of dinitriles, low selectivity, and substantial wastes. In 1967, William C. Drinkard at DuPont introduced direct butadiene hydrocyanation using zero-valent nickel–phosphite catalysts, rapidly earning predominance due to simplified operations and superior atom economy^[1][2].

Process Chemistry

The net reaction converts 1,3-butadiene and two equivalents of hydrogen cyanide (HCN) into adiponitrile:

The process reactions involve (Fig. 1):

Figure 1 - Formation of 3-pentenenitrile (3PN) and 2-methyl-3-butenenitrile (2M3BN) (approx. 2:1 ratio) via π-allyl intermediates^[1]

Academic and industrial mechanistic studies in the 1970s–1990s elucidated the catalytic cycle (Fig. 2)—oxidative addition of HCN to Ni(0), migratory insertion of butadiene to form π-allyl–nickel cyanide, and reductive elimination of pentenenitriles—guiding ligand innovations and process intensification^[1][3][4][5].

Figure 2 - Proposed cycle for the concurrent butadiene hydrocyanation and 2-methyl-3-butenenitrile (2M3BN) isomerization^[3]

Detailed Step-by-Step Process Description

A typical industrial scheme comprises three reactors in series, followed by catalyst recovery and distillation (block flow diagram illustration).

1. Primary Hydrocyanation
   • Reactants: Butadiene, HCN, Ni–phosphite catalyst (e.g., Ni[P(OC₆H₅Me-p)₃]₄)
   • Conditions: 80–130 °C, 5–20 bar^[9][10]
      
2. Isomerization
   • Catalysts/Co-catalysts: Same Ni complex with ZnCl₂ or alternative Lewis acid
   • Conditions: 60–120 °C, 1–10 bar
      
3. Secondary Hydrocyanation
   • Reactants: Recycled 3PN, HCN, Ni catalyst, Lewis acid (commonly AlCl₃)
   • Conditions: 30–130 °C, 1–20 bar
   • Product Purification: Multistage distillation achieves >99.5% ADN purity^[11][12][13]

Table 1 - Typical Conditions and Outputs

Process Efficiency

• Overall Yield: 97–99% of theoretical^[1][5]
• Single-Pass Selectivity: 81–87% to adiponitrile, with by-product minimization via recycling of intermediates^[5]
• Product Purity: >99.5% after distillation

Lewis acid choice significantly influences relative rates (k3/k4) and steady-state intermediate distributions (Table 2):

Table 2 - Lewis Acid Effects on Reaction Rates at 68 °C^[5]

Economic Performance

• Capital Expenditure: A world-scale (∼200 kt/y) plant requires 400–600 M USD for in-side battery limits (ISBL), with off-site facilities and start-up adding 30–50%
• Operating Costs Breakdown:
  • Butadiene (40–45%)
  • HCN (15–20%)
  • Catalyst & Ligand makeup (5–10%)
  • Utilities & overhead (25–30%)
• Minimum Sustainable Selling Price: Typically 1,700–1,900 USD/t, competitive with alternative ADN routes^[14]

Process intensification studies (e.g., hybrid modeling, ML-aided simulation) suggest 10–15% reductions in energy and raw-material consumption possible without major capital additions^[8].

Proprietary Technologies and Licensors

Table 2 - Major technology owners and licensors

*Electrohydrodimerization (EHD) of Acrylonitrile

Catalyst formulations (e.g., diphosphite, diphosphonite ligands) are heavily patented and trade-secret-protected, enabling incremental performance gains in selectivity and lifetime^[9][10][11].

The Direct Butadiene Hydrocyanation controls >90% of global ADN capacity, while Electrohydrodimerization (EHD) of Acrylonitrile has ∼5% market share (notably Asahi Kasei, Kishida Chemical). Adipic Acid Ammoniation/Dehydration is <5% and regionally deployed (e.g., BASF gas-phase units). Other Routes such as chlorocyanation or caprolactam degradation are marginal and largely obsolete^[6][7][8].

References

1. Hydrocyanation - Wikipedia
2. Adiponitrile - Wikipedia
3. Laura Bini. (2009). Mechanistic insights into the hydrocyanation reaction. [Phd Thesis 1 (Research TU/e / Graduation TU/e), Chemical Engineering and Chemistry]. Technische Universiteit Eindhoven. DOI: 10.6100/IR644067.
4. Wenwen Cong et al., Process intensification and economic evaluation of adiponitrile production based on hybrid modeling, Chemical Engineering and Processing -  Process Intensification, Vol. 213, (2025), 110325, ISSN 0255-2701, DOI: 10.1016/j.cep.2025.110325.
5. Zhang S. et al. (2019). Method for preparing adiponitrile using dialkyl adipate and ammonia via catalytic ammonolysis-dehydration. Chinese Patent CN 110511162 A, published Nov 29, 2019, application filed Jun 11, 2019, Institute of Process Engineering, Chinese Academy of Sciences.
6. D.E. Blanco et al. (2019). Enhancing selectivity and efficiency in the electrochemical synthesis of adiponitrile. Reaction Chemistry and Engineering, 4(1), 8-16. DOI: 10.1039/c8re00262b.
7. Hydrocyanation - CHEMEUROPE.COM
8. Adiponitrile Market - Forecast(2025 - 2031) - IndustryARC
9. Piet van Leeuwen et al. (2003). Process for the hydrocyanation of butadiene. European Patent EP1344770A1, published Sep 17, 2003, application filed Mar 10, 2003, Invista Technologies Saerl.
10. Laura Bini et al. Ligand development in the Ni-catalyzed hydrocyanation of alkenes. Chemical Communications, vol. 46, no. 44, 2010, pp. 8325–8334. The Royal Society of Chemistry. DOI: 10.1039/C0CC01452D.
11. J.M. Gartner et al. Hydrocyanation of 2-pentenenitrile. U.S. Patent US20120035387A1, filed Mar. 14, 2011; published Feb. 9, 2012. Invista North America LLC - Inv Nylon Chemicals Americas LLC.
12. S. Zhang, et al. [Method for preparing adiponitrile by direct hydrocyanation of butadiene]. Chinese Patent CN 111892514 A, filed Aug 13, 2020; published Nov 6, 2020. Yangquan Coal Group Design And Research Center Co ltd - Yangquan Coal Industry Group Co Ltd
13. Alexander P. V. Göthlich et al. Syntheses, Structures, and Nickel-Catalyzed Hydrocyanation of Conjugated Dienes. Organometallics 2007, 26 (5), 1184–1186. DOI: 10.1021/om701140c.
14. Q3 2024 - Adiponitrile Production from Butadiene and HCN, Adiponitrile Operating Costs & Plant Construction Costs - INTRATEC