Introduction to Long-Chain Dicarboxylic Acids

Long-chain dicarboxylic acids are aliphatic dicarboxylic acids containing 10 or more carbon atoms in their carbon chain (denoted as DCn, where n ranges from 10 to 18). They constitute a class of fine chemical products with significant and wide-ranging industrial applications. In the chemical industry, these compounds serve as crucial raw materials for the synthesis of high‑end fragrances, high‑performance nylon engineering plastics, premium paints and coatings, advanced nylon hot‑melt adhesives, high‑temperature dielectrics, superior lubricating oils, cold‑resistant plasticizers, resins, pharmaceuticals, and agrochemicals.

For example, DC11–DC18 can synthesize macrocyclic ketones with distinct fragrance profiles, such as muscone; PF nylon, which is tensile‑strong and wear‑resistant, can be molded into tire cord and used as a substitute for non‑ferrous metals, enjoying widespread applications in the aerospace, automotive, marine, and construction industries; high‑grade hot‑melt adhesives are employed as bonding agents in color picture tubes and deflection coils, with extensive uses and substantial consumption volumes.

Additionally, the longer‑chain aliphatic compounds DC18 and DC20 are currently employed as side chains in peptides; for example, DC18 is used in semaglutide, while DC20 is incorporated into tirzepatide.

Semaglutide (C18 building block)

Tirzepatide (a 20-carbon scaffold)

Production Methods and Industrial Chain of Long-Chain Dicarboxylic Acids

Long-chain dicarboxylic acids (C10–C18) were initially produced primarily via chemical synthesis. This approach is characterized by complex processes, stringent reaction conditions, numerous steps, low yields, poor purity, high costs, and significant environmental pollution. To date, only DC12 (dodecanedioic acid) has been commercialized, and chemical synthesis is limited to producing diacids with no more than 12 carbon atoms.

In recent years, biological methods have gradually replaced chemical approaches. Compared with chemical synthesis, biofermentation can produce dicarboxylic acids with 12 or more carbon atoms, significantly expanding the industrial applications of long-chain dicarboxylic acids, while also offering advantages such as lower costs, high conversion efficiency, reduced pollutant emissions, and mild production conditions.

Under the dual-carbon policy framework, fermentation-based processes offer clear environmental advantages over chemical synthesis, helping to reduce and lower carbon emissions. By leveraging fermentation technologies developed by the Institute of Microbiology, Chinese Academy of Sciences, various biofermentation methods can produce dicarboxylic acids; among them, yeasts of the genus Candida are highly efficient microorganisms for fermenting n-alkanes into dicarboxylic acids, and this technology has ultimately been successfully commercialized. China’s independently developed fermentation technologies are at the forefront of the industry. Ningxia NINGKE Biotechnology Co., Ltd. (referred to as “NINGKE,” stock code: 600165) operates a 50,000-ton-per-year production line for dodecanedioic acid (lauric acid, DC12). The company possesses fundamental strengths in strain cultivation, medium optimization, fermentation process control, and purification techniques, mastering third-generation biotechnological methods for the large-scale production of long-chain dicarboxylic acids. Its aqueous-phase extraction and purification process does not use chemical solvents, making it more environmentally friendly and green.

The method of producing long-chain dicarboxylic acids via biotechnological fermentation not only opens up a new source but also overcomes the challenge of synthesizing certain dicarboxylic acids by chemical means, thereby addressing critical gaps in the chemical industry. Given that microbial fermentation operates under mild conditions, involves fewer steps, delivers high yields, and incurs low costs, it enjoys a significant competitive advantage over conventional chemical synthesis, which is characterized by harsh reaction conditions, numerous steps, lower yields, and higher expenses.

Currently, China’s long-chain dicarboxylic acid industry and the nylon value chain are well-developed. Among them, only azelaic acid (DC9) and sebacic acid (DC10) are products for which both processes still have large-scale production capacities. The traditional chemical method uses castor oil or oleic acid as raw materials for pyrolysis, a mature process that still maintains substantial existing capacity; meanwhile, companies like NINGKE have recently achieved industrial-scale production of sebacic acid via the bio‑based route, with product quality significantly superior to the chemical method, gradually replacing conventional chemical‑process capacity—though the chemical method has not yet completely exited the market.

Main Production Methods of Long-Chain Dicarboxylic Acids and Their Corresponding Applications

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