Synthesis and characterization of toluene diisocyanate

Hisar Telli, Ayşegül
Toluene diisocyanate (TDI) is one of the important components of solid rocket propellants. It is used for the construction of polyurethane network by reacting with hydroxy terminated polybutadiene (HTPB) and functions as a curing agent. The aim of project, supported by Ministry of Science Industry and Technology under SANTEZ program in collaboration with ROKETSAN, is to synthesize TDI at laboratory scale by determining the best method/methods that give the product in high yield with desired isomer ratio and quality. Although TDI is in industrially important compound, most of the studies concerning the synthesis of this compound are patented. To the best of our knowledge, TDI is not produced in Turkey and there is no study related to the production of this chemical. In this project TDI synthesis was planned in three steps which are nitration of toluene, reduction of dinitrotoluene, and phosgenation of toluenediamine. Standard nitration method was applied in the first step but optimizations were necessary in order to get the product in required isomer ratio. In the second step, Raney Nickel was found to be the ideal catalyst for the reduction of nitro groups. Finally conversion of amine groups to isocyanate groups was achieved by triphosgene reagent. Structural characterizations were carried out via NMR and FT-IR.
Citation Formats
A. Hisar Telli, “Synthesis and characterization of toluene diisocyanate,” M.S. - Master of Science, Middle East Technical University, 2014.