The Color Reaction Of Nitric Oxide With Yttrium-Methyl Salicylate Complexes And Its Application

A characteristic color reaction occurs when nitric oxide (NO) reacts with the mixture of yttrium perchloric and methyl salicylate at a given temperature, forming a comparative, stable blue-green product. In this paper, the influence of reaction conditions on the formation of blue-green product was systematically studied and a simple and fast mean to detect NO was proposed, meanwhile the mechanism of this reaction was discussed.It was found that NO and NO2can form blue-green product with max absorptive wavelength at660nm in the absence of yttrium-methyl salicylate complexes in butyl acetate only when with high concentration of reactants. Interestingly, in the presence of yttrium-methyl salicylate complexes, the blue-green product can be formed fleetly with high concentration and high stability. This characteristic reaction can be considered to be an oxidation reaction of NO to form blue-green N2O3catalyzed by the coordination complex of yttrium perchloric and methyl salicylate. The kinetic study of this reaction reveal The reaction order of yttrium perchloric, methyl salicylate and NO in the elementary reaction are2,2and1respectively, also indicating that the coordination between yttrium and methyl salicylate play an important role in this reaction. The reaction rate constants at358K and353K were determined to be33.2and20.3mol*L-1*min-1, and the corresponding activation energy was calculated to be103.4kJ/mol.Base on the linear relation between the absorbance and the content of NO reacted, we propose a novel method to detect NO using yttrium-methyl salicylate complex as a chromogenic agent and butyl acetate as solvent, The optimal conditions and concrete steps were suggested as follow:butyl acetate solution with NO absorbed is mixed with excess of chromogenic agent in a10ml colorimetric tube and being heated at100℃for20min, After cooling in an cold water bath for10min, the resultant reaction was filled with butyl acetate to a total volume of5ml. Then determine the absorbance of reaction solution at640nm. The concentration of NO in sample was calculated according to the work curve drawn previously using standard solution of NO as the same procedure. This method is simple with good repeatability and stability, and the apparent molar absorption coefficient ε=8.54×102L·mol-1·com-·,detection limit:5.3×10-5mol/L.