SYNTHESIS AND THERMAL CHARACTERISTICS OF WATER-SOLUBLE BLOCKED O-TOLYLISOCYANATE

Abstract

Synthesis of latent reagents, in particular isocyanates, in a water-soluble form is a promising direction of chemical research. The replacement of isocyanates with their blocked analogues allows solving several problems: increasing safety in the use and storage of such toxic compounds as isocyanates, facilitating multi-stage synthesis in active media, increasing the selectivity of the main reaction, reducing the toxicity of reagents. In addition, due to the possibility of carrying out the blocking reaction of isocyanates in an aqueous media, the environmental safety of the process of their production is increased and the yield of the product is improved. In order to synthesize a water-soluble latent monoisocyanate for the modification of polymer systems, including water-soluble biopolymers, water-soluble sodium 6-(o-tolylcarbamoylamino)hexanoate was synthesized by the interaction of ortho-tolyl isocyanate with an aqueous solution of sodium salt of 6-aminohexanoic acid. The optimal temperature conditions for the synthesis of water-soluble blocked ortho-tolyl isocyanate were determined. The structure of the reaction product was proved using methods of IR- spectroscopy with Fourier transform and NMR 1H spectroscopy. According to the data of thermogravimetric analysis in dynamic mode and pyrolytic mass spectrometry the temperature range of the thermal dissociation of water-soluble ortho-tolyl isocyanate blocked by the sodium salt of 6-aminohexanoic acid ranges from 100 to 140°C and is wider than the temperature range of the thermal dissociation of the hydrophobic compound - ortho- tolyl isocyanate blocked by ε- caprolactam.