PURPOSE: To improve the trioxane conversion in obtaining the trioxane by bringing an aqueous solution of formaldehyde into contact with an acid catalyst, by carrying out the reaction in the presence of an inert fluid in the superctritical state or liquefied state under pressure and the heterogeneous phase conditions.
CONSTITUTION: An aqueous solution of formaldehyde is brought into contact with an acid catalyst in the presence of an inert fluid in the supercritical state or liquefied state under pressure to give trioxane. The above-mentioned inert fluid is obtained by changing an inert gas such as CO2 or a fluorohydrocarbon, e.g. CCl2F2, etc. into the supercritical state or liquefied state under pressure for use. The reaction temperature must be within such a range as to change the inert fluid into the supercritical state, and an advantageous temperature for producing the trioxane must be selected and is preferably 70W130°C in general. The reaction pressure is 35W350atm. The proportion of the inert fluid is about 0.2W2 times of that of the aqueous solution of the formaldehyde, and the residence time of the inert fluid is 0.1W120min in the continuous method.
FUJIMOTO TADAAKI
TANIGUCHI KATSUO
