Technology

Technology History

The direct hydrocyanation of butadiene to adiponitrile (ADN) was pioneered by William C. Drinkard at DuPont in 1967, representing a breakthrough in homogeneous catalysis that revolutionized ADN production^[1][2]. This technology replaced earlier multi-step chlorocyanation routes and became commercially operational in 1971 at DuPont's Orange, Texas facility, marking the 50^th anniversary of commercial ADN production in 2021^[3].

The process evolved from initial monodentate phosphite ligand systems to advanced bidentate phosphite ligand catalysts that offer superior performance in terms of selectivity, turnover rates, and catalyst stability^[4]. In 2012, INVISTA unveiled a transformative butadiene-based "new ADN technology" that achieved improved product yields, reduced energy consumption, lower CO₂ emissions, as well as virtually eliminating benzene from the production process^[5].

Technology Summary and Recent Technological Improvements

Core Process Chemistry

The INVISTA process employs a three-step hydrocyanation sequence (Fig. 1)^[6][7][8][9]:

1. Primary Hydrocyanation: 1,3-butadiene + hydrogen cyanaide (HCN) → mixture of 3-pentenenitrile (3PN) and 2-methyl-3-butenenitrile (2M3BN)
2. Isomerization: 2M3BN → 3PN (to maximize linear nitrile formation)
3. Secondary Hydrocyanation: 3PN + HCN → adiponitrile (+ minor 2-methylglutaronitrile)

Figure 1 - Hydrocyanation of 1,3-butadiene to adiponitrile^[7]
 

Recent Technological Improvements (2014 onwards)

Based on INVISTA's patent portfolio and commercial deployments^{[5][9][10][11][12]}:

• Benzene Elimination: Complete elimination of benzene formation as a by-product
• Enhanced Process Stability: More consistent operation and reliability
• Improved Yields: Higher conversion efficiency and product selectivity
• Reduced Energy Consumption: Better heat integration and process optimization
• Lower Greenhouse Gas Emissions: Environmental performance improvements
• Reduced Capital Intensity: Lower infrastructure requirements for new installations

Detailed Step-by-Step Technology Description

Process Flow Based on Patent Analysis

Figure 2 - Hydrocyanation of 1,3-butadiene to adiponitrile block flow diagram reconstructed based on patents US9040735B2^[13], US10035756B2^[14], EP1344770A1^[15], and related INVISTA filings

Step 1: Primary Hydrocyanation Reactor

Patent Basis: EP1344770A1^[15], US20080015378A1^[16]

• Reactants: 1,3-butadiene (<5 ppm 4-tert-butylcatechol) + HCN
• Catalyst System: 
  • Zero-valent nickel [Ni(COD)₂ preferred]
  • Bidentate phosphite ligands with specific structural formulae
  • Molar ratio butadiene:catalyst = 10:1 to 100,000:1 (preferred 100:1 to 5,000:1)
  • Molar ratio HCN:catalyst = 10:1 to 100,000:1 (preferred 100:1 to 5,000:1)
• Conditions:
  • Temperature: 25-200°C (preferred 50-150°C)
  • Pressure: 5 kPa to 10,000 kPa (preferred 500-2000 kPa)
  • Reaction time: 2 seconds to 24 hours
• Products: ~65% 3PN, ~35% 2M3BN mixture

Step 2: Isomerization Reactor

Patent Basis: US9040735B2^[13], research insights

• Feed: 2M3BN from primary hydrocyanation
• Catalyst: Same nickel-phosphite complex + Lewis acid co-catalyst
• Lewis Acid: ZnCl₂, AlCl₃, or other Lewis acids
• Conditions:
  • Temperature: 60-120°C (typical 80-120°C)
  • Pressure: 1-10 bar
• Mechanism: Reversible C-CN bond activation via σ-alkyl and π-allyl intermediates
• Performance: Single-pass conversion 26.4%, selectivity to 3PN: 79.8%

Step 3: Secondary Hydrocyanation Reactor

Patent Basis: US20120035387A1^[17], US9040735B2^[13]

• Feed: 3PN + 4PN from Step 1 and Step 2 + HCN
• Catalyst: Ni-phosphite complex + Lewis acid promoter (preferably ZnCl₂ or AlCl₃)
• Enhanced Water Control (US9040735B2): Water concentration maintained at 100-400 ppm to prevent ligand degradation
• Conditions: 
  • Temperature: 25-80°C (typical 30-130°C)
  • Pressure: 1-20 bar
  • Residence time: 5-40 hours (typical 15-30 hours)
• HCN conversion: >99%

Step 4: Catalyst Recovery and Product Purification

Patent Basis: US10035756B2^[14]

• Liquid-Liquid Extraction: Enhanced with Lewis base additives (water, ammonia, polyamines)
• Lewis Base Enhancement: Addition of bis-hexamethylenediamine (BHMT) or hexamethylenediamine (HMD) improves catalyst recovery efficiency
• Multi-stage Countercurrent Extraction: Cyclohexane as extraction solvent
• Distillation Train: Four-column system for ADN purification

Process Conditions and Parameters Summary

Technology Performance

Yields and Selectivity

Based on patent examples and literature data^[6][9]:

• Overall ADN Yield: 97-99% of theoretical
• Primary HCN Selectivity: 3PN ~65%, 2M3BN ~35%
• Isomerization Efficiency: 79.8% selectivity to 3PN
• Secondary HCN Selectivity: 81-90% to ADN (depends on Lewis acid)
• Product Purity: >99.5% ADN after distillation

Energy Efficiency

Recent INVISTA improvements^[16]:

• Reduced energy consumption through advanced heat integration
• Enhanced process stability reducing energy losses
• Optimized catalyst recovery reducing regeneration energy

Economic Performance

While specific cost breakdowns remain proprietary, the process economics are driven by:

• Raw Material Efficiency: >97% conversion of butadiene and HCN^[13][15][18]
• Catalyst Costs: Significant but offset by high recycling efficiency and long catalyst life^[13][14][19]
• Energy Costs: Reduced through process intensification^[10][11][12]
• Capital Efficiency: Improved through INVISTA's latest technology reducing capital intensity^{[10][11][12][18]}

Commercial Experience

Global Deployment Timeline

• 1971: First commercial plant (Orange, Texas)^[3]
• 2014: "New ADN technology" deployed at Orange, Texas^[20]
• 2017: Technology retrofit at Butachimie JV (France)^[10][12]
• 2021: Installation at Victoria, Texas ($250M investment)^[21]
• 2022: Deployment at Shanghai, China (400,000 t/y capacity)^[21]
• 2024: ADN production at Orange, Texas, shut down^[23] 

Market Position

• INVISTA: Dominant technology licensor with >90% of global ADN capacity using hydrocyanation
• Major Producers: INVISTA, Butachimie (INVISTA/Solvay JV), BASF SE
• Technology Licensing: INVISTA and Butachimie are primary licensors for new plants
• Competitive Advantage: Proprietary catalyst formulations and process optimization provide sustained market leadership^[18]

Proprietary Technology Elements

Based on the patent analysis, INVISTA's competitive advantages include^{[13][14][15][16][17]}:

1. Catalyst Systems: Proprietary bidentate phosphite ligand formulations
2. Process Integration: Advanced heat integration and separation technologies
3. Lewis Acid Optimization: Specific promoter combinations for enhanced selectivity
4. Water Management: Critical water concentration control for catalyst stability
5. Extraction Enhancement: Polyamine additives for improved catalyst recovery
6. Benzene-Free Innovation: undisclosed process modifications virtually eliminating benzene formation

References

1. William C. Drinkard - Wikipedia
2. William C Drinkard, Richard V Lindsey Jr, Hydrocyanation of olefins using selected nickel phosphite catalysts, United States Patent US3496215A, Patent Filed: Nov 11, 1965, EI Du Pont de Nemours and Co
3. Nov 1987 - Health and Environmental Effects Document for Adiponitrile - U.S. Environmental Protection Agency (EPA)
4. Ronald James Mckinney, Process for the hydrocyanation of butadiene, European Patent EP1344770A1, Invista Technologies Saerl
5. PlasticsToday Staff, May 18, 2012 - Invista unveils new production technology for key nylon intermediate - PLASTICS TODAY
6. Xuan Luo et al., Production technology of adiponitrile, E3S Web of Conferences,Vol. 441, Article Nr. 01019, (2023), DOI: 10.1051/e3sconf/202344101019
7. Kaikai Liu, Research on Catalysts for the Hydrocyanation of 1,3-Butadiene to Adiponitrile, 2020 Virtual AIChE Annual Meeting, ISBN 978-0-8169-1114-1
8. Liu, Kaikai, Shuai Zhang, and Minghan Han. 2020. Mechanistic Investigation on Hydrocyanation of Butadiene: A DFT Study. Catalysts 10, no. 8: 818. DOI: 10.3390/catal10080818
9. 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
10. Sep 27, 2017 - Invista to Install New ADN Technology in France - CHEManager
11. TORZEN^® Nylon 6,6 Engineering Polymers Brochure - STUDYLIB
12. Mary Bailey, Sep 21, 2017 - Invista to install new adiponitrile process technology at Butachimie site in France - Chemical Engineering
13. Aki Sudhir et al., Process for making nitriles, United States Patent US9040735B2, Patent filed: Oct 4, 2012, Invista North America S.a.r.l.
14. William J. Tenn, Integrated process for nitrile manufacture with enhanced liquid-liquid extraction, United States Patent US10035756B2, Patent filed: Jun 25, 2015, Invista North America S.a.r.l.
15. Ronald James McKinney, Process for the hydrocyanation of butadiene, European Patent EP1344770A1, Patent filed: Mar 10, 2003, E.I. du Pont de Nemours and Company
16. Thomas Foo et al., Process for making 3-pentenenitrile by hydrocyanation of butadiene, United States Patent US20080015378A1, Patent filed: Jul 12, 2007, Invista North America LLC
17. James Michael Gartner et al., Hydrocyanation of 2-pentenenitrile, United States Patent US20120035387A1, Patent filed Feb 7, 2011, Invista North America S.a.r.l.
18. Q3 2024 - Adiponitrile Production from Butadiene and HCN, Adiponitrile Operating Costs & Plant Construction Costs - INTRATEC
19. 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
20. Dec 17, 2018 - INVISTA’s Orange, Texas, Site Sets Adiponitrile Production Record - Defence Industries
21. Mar 26, 2021 - Invista Concludes Technology Upgrade at Victoria ADN Plant - Process Worldwide
22. Nov 25, 2022 - INVISTA Celebrates Inauguration of 400,000-ton/year ADN Plant at the Shanghai Chemical Industry Park - INVISTA
23. Oct 10, 2023 - INVISTA Closes Texas Facility, Amplifying Its Strategic Commitment to Shanghai - China Chemical Market Insights