【Ten Years of Rapid Development in Chemical Equipment】From 2019 to 2025, China achieved full-scale industrialization of MDI production via the urea route without the use of phosgene

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Kudos and encouragement to China for its achievements in chemical technology and equipment! Your participation in the discussions serves as the greatest motivation. ********************** [Ten Years of Great Development in Chemical Equipment] This is a continuously updated thread; everyone is welcome to join the discussion: https://bbs.hcbbs.com/thread-3576046-1-1.html ***************** China has successfully completed the full industrial-scale testing process for the urea-based method of producing MDI without using phosgene. On February 8, 2025, the Institute of Process Engineering at the Chinese Academy of Sciences announced that the green production technology for diphenylmethane diisocyanate (MDI) developed in collaboration with the Shaanxi Coal Technology Development Center and the Shaanxi Coal & Chemical Industry Technology Research Institute has undergone successful full-process calibration within an industrial-scale test facility. During the tests, the facility operated stably, yielding satisfactory results that met all expected standards. Isocyanates are important raw materials for producing polyurethanes, which are strategic engineering plastics; among them, diphenylmethane diisocyanate (MDI) is a representative product that is widely used in key industries such as automobiles, wind power, and high-speed railways. There are two MDI production methods: the phosgene method and the non-phosgene method. Most manufacturers around the world use the phosgenation method to produce MDI; the main raw materials include benzene, liquid chlorine, and carbon monoxide. The production process involves steps such as the amination of benzene, phosgenation, and subsequent purification. ? The phosgene-free method is a method for producing MDI without using phosgene as a raw material; it mainly includes the urea method and the dimethyl carbonate method, among others. The specific steps are as follows: Aniline and urea are added to the reactor in a certain molar ratio; the reaction temperature and time are controlled to produce MDI and the by-product water; finally, separation and purification are carried out to obtain MDI products with high purity . The urea process for producing phosgene-free methylene diphenyl diisocyanate (MDI) demonstrates significant economic advantages over the traditional phosgene process. Firstly, the urea method uses inexpensive and readily available urea and aniline as raw materials, thereby significantly reducing production costs, whereas the phosgene method relies on highly toxic phosgene, resulting in high costs for its storage, transportation, and safety measures. Secondly, the urea method eliminates the use of phosgene, which not only improves production safety but also reduces additional costs associated with safety measures. Additionally, the urea process does not involve phosgene during production, thereby reducing the emission of harmful substances and alleviating environmental pressure; it also lowers waste treatment costs. In contrast, the phosgene process generates by-products such as hydrogen chloride, which require additional treatment, thus increasing environmental protection costs. At the same time, the production process using urea is relatively simple, with lower equipment investment and operating costs, whereas the phosgene process is complex, requires sophisticated equipment, and incurs higher maintenance and operating costs. Finally, the urea process complies with current environmental policies and may qualify for government subsidies or tax incentives, whereas the phosgene process faces stricter regulations and a higher risk of penalties. In summary, the urea process outperforms the phosgene process in terms of raw material costs, safety, environmental friendliness, process simplification, and policy support; thus, it has become a more economically advantageous production method. This technology uses bulk chemicals such as aniline, urea, and formaldehyde as raw materials to produce isocyanates (MDI) through a phosgene-free process route. It represents a green upgrading technology for key industries that is strongly encouraged under the \"Dual Carbon Strategy,\" as well as the future direction for MDI production technologies. After 10 years of technical research and development, the R&D team has overcome a series of core and key technologies. They successfully completed the entire process in an industrial-scale pilot plant, carried out calibration tests, and achieved the expected results. Consequently, they have mastered a set of green manufacturing technologies for phosgene-free isocyanate (MDI) with independent intellectual property rights. This technology establishes an overall process route characterized by high atom economy and inherently safe production processes. It facilitates the construction of production facilities of various scales and a diversified product portfolio, thus holding great potential for widespread application. The R&D team will further optimize the complete set of technologies to accelerate the implementation of large-scale projects. The research teams led by researchers Li Huiquan and Wang Liguo from the Institute of Process Engineering have been engaged for a long time in the development of key technologies for the green synthesis of non-phosgene isocyanates as well as their industrial implementation. They have developed integrated green process technologies for the entire production chain, including mild hydrogenation of nitroaromatics, the production of isocyanates without the use of phosgene, and the mild production of epichlorohydrin through short-process methods. Additionally, they have established a comprehensive technical system for the production of various series of products, such as bulk aromatic isocyanates (MDI), specialty aliphatic isocyanates (XDI, HDI), and bio-based isocyanates (PDI), all via non-phosgene routes. At the same time, collaborations are being carried out with industry leaders to carry out technology research and development as well as engineering applications, in order to support and drive the green and high-end development of the isocyanate-polyurethane industry chain. The research and development of this technology has continued to receive support from projects such as the **National Natural Science Foundation, the Key Direction Projects of the Chinese Academy of Sciences’ Knowledge Innovation Program, the **Science and Technology Support Program, the Strategic Priority Research Programs of the Chinese Academy of Sciences, and the **Key R&D Program.