Reactivity of organic isocyanates with nucleophilic compounds: amines; alcohols; thiols; oximes; and phenols in dilute organic solutions

The routine analysis of organic micro-pollutants, introduced into the environment through the 16 use of pesticides, is a problem that has still not been fully resolved. The search for a new 17 derivatizing agent for those pollutants, which should be as universal as possible, has led us to study organic isocyanate reactivity with numerous nucleophilic compounds, such as alcohols, phenols, amines, thiols and oximes. Our research extends current knowledge concerning the reactivity of isocyanates with alcohols and low concentrations of nucleophilic compounds. In aprotic solvents with triethylamine, the derivatization of amines or oximes as a catalyst down to concentrations on the order of 10 −4 M performs quantitatively. On the contrary, for alcohols, phenols and thiols, the derivatization level decreases with decreasing concentration. At 10 −4 M, the derivatization ratio is inversely proportional to the nuclephile/isocyanate ratio, which constitutes a strong limitation to the use of isocyanates for the derivatization of residues in aprotic solvents.