Blocking and Deblocking of Diisocyanate to Synthesize Polyurethanes was written by Jana, Sourita;Samanta, Debasis;Fahad, Mir Muhammad;Jaisankar, Sellamuthu N.;Kim, Hongdoo. And the article was included in Polymers (Basel, Switzerland) in 2021.Electric Literature of C9H7BrN2 This article mentions the following:
Diisocyanates, particularly toluene diisocyanate (TDI), are useful for the preparation of various polyurethanes with specific applications as leather-like materials, adhesives and insoles, etc. Blocking agents can be used for the operational simplicity and to reduce the hazards of TDI. In this paper, we reported the use of 3-(4-bromo-phenyl)-1H-pyrazole to block toluene diisocyanate (TDI). FTIR, NMR, thermogravimetric anal., contact angle anal. and differential scanning calorimetry (DSC) were used for the characterization. The effectiveness of the blocking was confirmed by spectroscopic techniques. The DSC thermogram showed that blocked adducts deblock at 240°C, causing the regeneration of TDI, and causing the diisocyanates to react with polyols of different mol. weights, forming polyurethanes. The characterization of the polyurethanes was performed by IR spectroscopy, NMR spectroscopy, thermogravimetric anal., differential scanning calorimetry and a contact angle study. In the experiment, the researchers used many compounds, for example, 3-(4-Bromophenyl)-1H-pyrazole (cas: 73387-46-9Electric Literature of C9H7BrN2).
3-(4-Bromophenyl)-1H-pyrazole (cas: 73387-46-9) belongs to pyrazole derivatives. Pyrazole is a weak base, with pKb 11.5 (pKa of the conjugated acid 2.49 at 25 °C).Pyrazole used as a ligand to prepare organometallic compounds. Pyrazole the presence of this nucleus in pharmacological agents of diverse therapeutic categories such as celecoxib, a potent anti-inflammatory, the antidepressant agent fezolamide have proved the pharmacological potential of the pyrazole moiety. Electric Literature of C9H7BrN2
Referemce:
Pyrazole – Wikipedia,
Pyrazoles – an overview | ScienceDirect Topics