Achieving independent control over key raw materials for high-end nylon - Record of the award-winning project "Development and Industrialization of High-Quality Caprolactam Technology for Key Components of Polyamide-66"
Recently, the "Key Technology Development and Industrialization of High-Quality Hexamethylenediamine by Hexaminoamide Method" project, jointly completed by Jiangsu Yangnong Chemical Group Co., Ltd., Xiamen University, and Ningxia Ruitai Science and Technology Co., Ltd., has won the First Prize of China Petroleum and Chemical Industry Association's Scientific and Technological Progress Award for 2025. This achievement has created a brand-new process route for producing high-quality hexamethylenediamine using hexaminoamide as the raw material, and has built the world's first 10,000-ton industrialization facility, achieving independent control of the key raw material for high-end nylon.
Innovative process breaks bottlenecks and frees from reliance on hexadecynone
Hexamethylenediamine is an indispensable core monomer for high-performance materials such as nylon 66, special nylon, and high-end polyurethane curing agents, and is widely used in important fields of the national economy such as automobiles, electronics and electrical appliances, and rail transportation. However, for a long time, China's hexamethylenediamine production has been highly dependent on the traditional process with hexadecynone as the core, and the industrial chain security and profit distribution have been subject to others' control, becoming a "shortage" problem that hinders the development of the high-end chemical new materials industry.
Facing this predicament, the project team abandoned the traditional hexadecynone route and took a new path, using the bulk chemical hexaminoamide as the raw material, and directly preparing hexamethylenediamine through two steps of catalytic ammoxidation and hydrogenation. This innovation not only successfully bypassed the technical blockade of hexadecynone, but also avoided using toxic or highly corrosive raw materials from the source.
Based on this, the team developed a full-process independent technology covering "catalyst preparation - hexamethylenediamine synthesis - nylon 66 polymerization", breaking through key technologies such as "high-performance catalyst preparation", "efficient utilization of heat-sensitive materials", and "separation and purification of ultra-pure products", and applying for 87 patents, with 50 of them being granted. Due to the low "three-waste" emissions and prominent green and low-carbon characteristics in the production process, this technology was also included in the "Petrochemical Green and Low-Carbon Process List (2024 Edition)" released by the China Petroleum and Chemical Industry Association.
Thousand times of exploration to overcome difficulties - the first industrial facility operates stably
From the laboratory to industrialization, the team has gone through thousands of explorations. Ding Kehong, the General Manager of the Innovation Center of China National Chemicals Chemical Division, introduced: "The core challenge lies in the fact that hexaminoamide is prone to polymerization during the high-temperature catalytic ammoxidation process, leading to catalyst deactivation. How to create a catalyst with high activity, long life, and excellent selectivity is the biggest challenge on the industrialization path."
The project team started from the fundamental principles of catalytic science, innovatively proposed coupling strategies such as composite formulation, surface regulation, and structure strengthening, and successfully developed a highly active, long-lasting, and excellent-selective catalyst, laying the foundation for the stable, long-term, and excellent operation of the 10,000-ton industrial facility.
In May 2022, this technology was put into industrial application at the 40,000-ton nylon 66 and 25,000-ton hexamethylenediamine production facility of Ningxia Ruitai Science and Technology Co., Ltd. Before the start-up, the circulation of personnel and materials was extremely difficult. Wang Genlin, the Vice President and General Manager of the Technology Center of Yangnong Group, recalled: "At that time, to ensure the successful start-up, dozens of core technicians and engineers resolutely 'went against the flow' and moved into the factory, working around the clock for debugging. When the first hexamethylenediamine sample reached a purity of over 99.9%, there was a loud cheer at the scene, and many frontline workers were so excited that they shed tears."
Afterwards, the team quickly shifted from the "start-up debugging mode" to the "optimization breakthrough mode", and the product purity rapidly increased to over 99.998%, with key impurity indicators better than international benchmark products. Currently, the facility has been continuously operating stably for nearly 4 years. After being evaluated by an expert group led by two academicians organized by the China Petroleum and Chemical Industry Association, this achievement "has overall technology reached the international leading level".
Technology blossoms and bears fruit, empowering multiple industries
Now, this technology has borne fruit and entered the mature stage of industrialization promotion. The high-quality adipic acid produced by the company has been stably applied in various high-value fields such as nylon 66 engineering plastics and fibers, special nylon, and high-end polyurethane curing agents. This has helped downstream customers achieve the domestic substitution of key raw materials and empowered multiple industries such as electronics and electrical appliances, as well as textile and clothing.
In the future, Yangang Group will fully promote the expansion and upgrading project of existing facilities to double the production capacity, reaching an annual output of 80,000 tons of nylon 66 and 50,000 tons of adipic acid. This will further consolidate its competitive advantage. At the same time, the company will extend to high-value-added downstream products, actively develop differentiated nylon 66 and special nylon, and build a more competitive nylon new material industrial cluster. In addition, the project team has led the formulation of a technical group standard for high-quality adipic acid produced by the adipic acid method, aiming to convert the technical advantages into standard advantages and lead the healthy and standardized development of the entire technical route.
