Toluene diisocyanate (TDI) is the basic raw material for the production of polyurethane, mainly used in the production of flexible polyurethane foam and polyurethane elastomers, coatings, adhesives, etc., and is a widely used key chemical raw material . At present, the most advanced production process of TDI is synthesized by gas-phase phosgenation of toluene diamine (TDA) and phosgene, but this process still has the disadvantages of high energy consumption and high temperature side reactions. The team of Associate Professor Bi Rongshan from the School of Chemical Engineering, Qingdao University of Science and Technology proposed a flash atomization-assisted phosgenation method (PRFA) for the TDI synthesis process. The contact of the gaseous reactants makes the TDA micro-droplets vaporize instantly and undergo phosgenation reaction (the reaction mechanism is shown in Figure 1), thereby reducing the energy consumption required for TDA evaporation and heating.
Figure 1. Schematic diagram of TDA single droplet reaction mechanism
Figure 2. Process flow of atomization-assisted phosgenation
Through the simulation analysis of the PRFA process flow (Figure 2), and a comprehensive analysis and comparison with mainstream processes, it is found that the PRFA method has obvious advantages in TDA droplet life, reaction temperature, droplet size change, and reaction interface update. Under the new process, the energy consumption during the phosgenation reaction is also greatly reduced, and the average and maximum reaction temperatures are much milder than the state-of-the-art gas-phase method currently used in industry. These findings prove the new technology, economy and environment. The PRFA process has a good application prospect.
This work is titled "Novel atomization-assisted phosgenation for TDI synthesis from TDA: A "Theoretical study on single droplet reactivity" was published in Chemical, the TOP journal of the Chinese Academy of Sciences Engineering On Science, the link to the paper is https://doi.org/10.1016/j.ces.2023.119018. Associate Professor Bi Rongshan from the School of Chemical Engineering, Qingdao University of Science and Technology is the corresponding author of the paper. The research was funded by the Natural Science Foundation of Shandong Province.
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