Formation Of Nitrogen Oxides And Nitrosation Reaction Induced By The Coordination Of Ester Salicylate With Yttrium Nitrate

A characteristic coloration reaction between yttium nitrate and methyl salicylate in ethyl acetate solution occurs at refluxing temperature and forms a green product with strong absorption at around 660nm. In this paper, the reaction solutions or products formed under different reaction conditions, such as feeding mole ratio and reaction time, were characterized by means of cyclic voltammetry and UV, IR, HNMR, MS techniques. It was found that the appearance of reduction peaks in the cyclic voltammetry curves was directly related to the formation of green product, and the peak current values were proportional to the absorbance at around 660nm. At the same time, the green solution turned to blue when reacting with KI-amylum, indicating the existing of NO₂^- in the resulting solution. These facts showed that there exists a typical nitrosation reaction, because the reduction peaks in the I-V curves of green product and its acidified solution could be ascribed to typical nitroso aromatic compound. Furthermore, the IR spectra, HNMR spectra and MS spectra of some intermediates or products also provided evidences for the nitrosation reaction. Based on above facts, we suggested that it was the coordination reaction of methyl salicylate with yttrium ion that induced the formation of nitrous oxides NO_x and NO₂^-, and resulted in the subsequent nitrosation reaction between methyl salicylate yttrium coordination compound and nitrous oxides NO_x or NO₂^-.In the case of triethylene glycol ester of disalicylate, similar reaction was observed. However, the reaction speed decreased and more solid green product isolated due to the sterically hindering of ester group.