The remarkable effect of organic salts on 1,3,5-trioxane synthesis

The effects of organic salts on 1,3,5-trioxane synthesis were investigated through batch reaction and continuous production experiments. The organic salts used include sodium methanesulfonate（CH3NaO3S）, sodium benzenesulfonate（C6H5NaO3S）, sodium 4-methylbenzenesulfonate（C7H7NaO3S）, and sodium 3-nitrobenzene sulfonate（C6H4NNaO5S）. It was shown that the effects of organic salts on the yield of 1,3,5-trioxane in reaction solution and distillate follow the order CH3NaO3S ／C6H5NaO3S／C7H7NaO3S／C6H4NNaO5S, which is inversely related to the charge density of the anions of the organic salts. In comparison with Cl–-based salts such as magnesium chloride, organic salts have the advantages of less formic acid generation and low corrosion. Studies on water activity revealed that the effect of organic salts on the activity of water was quite small at low concentration of organic salts. UV–visible spectroscopy and vapor–liquid equilibrium experiments were performed to uncover the mechanisms that govern such effects. The results showed that the effect of organic salts on the yield of 1,3,5-trioxane relies primarily on their ability to increase the catalytic activity of sulfuric acid and increase the relative volatilities of 1,3,5-trioxane and water and of 1,3,5-trioxane and oligomers.