The Reactivity Of Methyl Salicylate With Yttrium Nitrate And Its Application

Nitrosation is an important pathway in the metabolism of nitrogen oxide in many biological systems, which plays a critical role in numerous physiological processes. So, the formation of nitrogen oxides and their reactivity has been received very potential attention in biochemistry and supermolecular chemistry. In this paper, the reactivity of yttrium nitrate with methyl salicylate was inverstigted, and the formation of nitrgen oxides and following nitrosation reaction was discussed.A characterization coloraction takes place when refluxing the mixture solution of yttrium nitrate and methyl salicylate. The resulting solution or solid complex shows deep green color with two broad absorption bands at ca.330nm and ca.660nm, which are attributed from the Ï€^* - Ï€^* and n- Ï€^* transition of C-nitroso compound and show the formation of nitroso compound. The molar absorption coefficient(ε) at 660nm was determined by slope method to be 6.922×10² L.mol^-1.cm^-1. At the same time, infrared spectrum(IR) of isolated solid complex also show the formation of C-nitroso compound.A induction period is observed for the formation of nitroso complex. With the increase of reactant concentration and reaction temperature, this induction period will be shortened and the following reaction rate will be speeded. The activation energy of nitrosation reaction was determined to be 177.8KJ·moL^-1. The reaction orders for yttrium nitrate and methyl salicylate are 2.3 and 1.5 respectively, indicating that the reaction is not a simple elementary reaction, but complex reaction including many reaction steps.The results also indicate that this color reaction usually takes place between rare earth nitrates and salicylate ester compound, which beares a hydroxyl group and a carbonyl group in adjacent positions that act as a proton donor acid and acceptor base respectively. The fact of reaction rate decreasing linear with the steric hindrance of ester groups shows that the formation of ring coordination compound between rare earth ions and salicylate ester takes an important role in the nitrosation reaction.Porous cubic yttrium oxides with high specific surface area have been prepared by the explosive decomposition of yttrium nitrate and its complex formed with methyl salicylate. The surface properties of synthesized powders were characterized using BET,X-ray diffraction(XRD), Infrared spectra(IR) and scanning electron microscopy (SEM). The results indicate that the highest specific surface area is found to be 65.37 m2g4 at calcination temperature 600°C, and then decreases to 20.33 m^g"1 with the calcination temperature rising from 600 to 900 "C. At the same time, they show strong surface activity for adsorpting water and carbon dioxide in air, which also decreases with the calcination temperature rising. The drop both on the surface area and surface activity for samples at higher temperatures may be due to pore-narrowing(sintering) effects.