Direct synthesis of hexamethylenediamine from caprolactam: Technological Breakthrough, Industrialization Progress, and Strategic Significance

己内酰胺直接制己二胺的技术突破，标志着我国在尼龙66关键原料领域已打破国外长期技术垄断，走向产业化自主的新阶段。该技术以己内酰胺、氨和氢气为原料，通过催化氨化与加氢反应，绕过了传统的己二腈环节，形成了更安全环保、原料易得的工艺路线，整体技术已达到国际领先水平。目前，多家企业已实现万吨级装置的投产或即将投产，该路线在规划产能中的占比正显著提升，正重塑国内尼龙新材料产业链的竞争格局。此项创新不仅实现了从煤焦化到高端聚酰胺的产业链贯通与升级，更对我国保障化工新材料供应链安全、提升产业竞争力具有深远的战略意义。

Hexamethylenediamine (HMDA), as a key monomer for high-performance materials such as nylon 66, nylon 610, polyurea elastomers, and epoxy resin curing agents, is a fundamental raw material supporting the development of high-end manufacturing industries like automotive lightweighting, aerospace, electronics, and new energy. However, for a long time, the production technology of the upstream key raw material—hexamethylenedinitrile (HMDA)—especially the butadiene method, has been monopolized by a few international chemical giants like Invista, resulting in severe challenges for China in terms of high raw material costs and dependence on supply security in this field.

为打破这一技术壁垒，保障产业链自主可控，我国科研与产业界积极开拓非己二腈路线。其中，以国内产能充足的己内酰胺为原料直接制备己二胺的技术路线，因其工艺协同性强、原料供应稳定、安全环保等优势，已成为实现产业突围的重要战略路径之一。本文旨在对该路线的关键技术、产业化进展、经济效益及未来挑战进行系统性梳理与剖析。

The direct process of converting caprolactam to hexamethylenediamine is essentially a ring-opening-amination-hydrogenation process. Its core lies in bypassing the traditional route of synthesizing hexanediamine by transforming caprolactam molecules into hexamethylenediamine with the same carbon chain length.

核心反应路径：该工艺通常以己内酰胺、氨气和氢气为原料，分两步进行。

氨化反应：己内酰胺首先在催化剂（如磷酸盐催化剂）作用下，与氨发生气相氨化反应，生成中间体6-氨基己腈（ACN）。

加氢反应：生成的6-氨基己腈随后在另一催化剂作用下，进行连续催化加氢反应，最终得到目标产物己二胺。

技术突破点：中化国际、厦门大学等单位联合开发的技术表明，该工艺的关键在于开发高性能的专用催化剂和反应器。例如，他们开发的高选择性、高强度多级孔结构氨化催化剂，单程寿命超过8000小时；开发的基于双金属协同氢溢流机制的加氢催化剂，可使6-氨基己腈转化率大于99.9%，最终产品纯度高达99.998%。

In recent years, the caprolactam method for producing hexamethylenediamine has transitioned from the laboratory to industrialization in China, with multiple companies actively planning and constructing production facilities.

1.代表性技术成果与企业动态

表：己内酰胺制己二胺代表性技术成果与企业项目

2.产能格局变化

根据行业资讯数据，在2025年中国规划的约30万吨己二胺新增产能中，己内酰胺法路线占比已达约43%，与传统的己二腈法（主要是丁二烯法）形成并驾齐驱之势。这表明该路线已获得产业界的实质性认可，正成为重塑国内己二胺供应格局的重要力量。

Multiple Dimensional Competitive Advantage

原料与工艺协同性高：对于已拥有大型己内酰胺生产装置的企业（如中国石化、中国石油及部分民营巨头），此路线能高效盘活现有资产。企业可根据市场需求，灵活调节己内酰胺用于生产尼龙6或转化为己二胺用于尼龙66的比例，实现“一头两尾”的柔性生产，极大增强了抗市场波动能力。

The process flow is relatively short and environmentally friendly: Compared to the traditional adipic acid method (which involves lengthy steps and nitric acid oxidation, producing the potent greenhouse gas N₂O), the caprolactam method involves fewer steps and avoids the use of nitric acid, thereby eliminating a major source of pollution at its origin, offering significant environmental advantages.

Investment and technology barriers are relatively manageable: Compared to the butadiene method, which requires massive investment and is constrained by international patents, the core technology of the caprolactam method has already achieved breakthroughs domestically. The investment in facilities is relatively less, providing a feasible path for domestic enterprises to avoid technological monopoly and achieve independent supply.

Phase-specific cost advantage: In recent years, as the domestic caprolactam market price has been relatively low while the price of hexamethylenediamine has remained at a certain high level, the price difference between the two has been significant. This substantial price gap offers companies using the caprolactam method a considerable profit margin, which is the direct economic motivation driving the rapid planning of capacity along this route.

2. Main Challenges and Constraints

The long-term sensitivity of raw material costs: The economic viability of this route is highly dependent on the market price of caprolactam. If the price of caprolactam rises significantly due to supply and demand relationships, its cost advantage will be quickly undermined.

Competing with the scale effect of the butadiene process: The internationally mainstream butadiene process (such as INVISTA technology) has a large single-line production capacity, providing a strong scale effect and long-term cost optimization potential. In contrast, the scale of caprolactam process facilities is usually limited by the capacity of upstream caprolactam units, making it difficult to compete with top butadiene processes in terms of absolute cost. It is more of a strategic supplement and a flexible choice.

技术进步与工程化的持续需求：尽管已有成功案例，但要保证不同企业、不同装置都能实现长周期、高效率、低消耗的稳定运行，仍需在催化剂寿命、反应器设计、热能综合利用和杂质控制等方面进行持续的工程优化和技术迭代。

The production of hexamethylenediamine using the caprolactam method is not only a chemical process route but also has profound industrial strategic significance.

保障产业链安全：该技术路线的成熟与推广，打破了我国己二胺生产对进口己二腈的绝对依赖，为尼龙66这一重要材料产业链的稳定运行提供了“备份”方案，增强了供应链的韧性和安全性。

促进产业结构优化：它使得国内庞大的己内酰胺产能有了新的高价值转化出口，有助于消化部分过剩的己内酰胺产能，推动整个尼龙产业向更高附加值、更多元化的产品结构升级。

The exemplary model of independent technological innovation: From being "choked" to independent breakthroughs, the development path is a vivid reflection of the Chinese chemical industry's commitment to independent innovation and overcoming key core technologies, providing valuable experience for other industries facing similar challenges.

Looking to the future, the development of adipic acid production using the caprolactam method will be closely linked toAdiponitrile domestication process and exploration of bio-based routesThe diverse supply pattern of hexamethylene diamine is shaped jointly. For enterprises, integrated manufacturers with upstream caprolactam resources will have a greater competitive advantage.Continuous technological research and development for cost reduction and efficiency improvement.Expanding the application of hexamethylenediamine in new energy, special materials, and other emerging fields will be key to the continued development of this pathway.

The technology for direct conversion of caprolactam to hexamethylenediamine has achieved a critical transition from technical breakthrough to industrialization in China, becoming an important strategic pathway to ensure the safety of the high-end nylon industry chain and promote diversified development in the industry. Despite facing challenges such as fluctuations in raw material costs and competition from mainstream routes, its outstanding advantages in process synergy, investment flexibility, and supply autonomy determine that it will play an indispensable role in the future supply pattern of hexamethylenediamine in China and globally. Continuous technology optimization, industrial chain integration, and application market expansion will be the core driving forces for the sustainable development of this technological route.