Tetra-n-butylammonium iodide and iodine were dissolved in anhydrous ethanol, respectively, and proportioned according to n(n-Bu4NI)=5mmol, n(I2)n(n-Bu4NI)=1, 2, 3, 4, 5. Under stirring at 80C, the ethanol solution containing iodine was added dropwise to the ethanol solution of tetra-n-butylammonium iodide, and refluxed for 3h. where when n(I2)n(n-Bu4NI)=1, a Black needle-like crystals precipitated, when n(I2):n(n-Bu4NI) 2, black flowing melt appeared at the bottom of the bottle, cooled to room temperature, the melt condensed into lumps, pumped filtration, ethanol washed, and one of the products obtained was tetra-n-butylammonium triiodide salt.
