| Abstract: | Three cyclic polymers of formaldehyde, namely, trioxane, 1,3,5,7-tetraoxocane, and 1,3,5,7,9-pentaoxocane, were reacted with acetic anhydride containing a catalytic amount of sulfuric acid. The progress of each reaction was followed by GLC. The cyclic compounds increased in reactivity with increasing molecular weight. The first step in each reaction was a ring opening, which produced a poly(oxymethylene diacetate) containing the same number of formaldehyde units as in the original cyclic compound. The poly(oxymethylene diacetate) then reacted with additional acetic anhydride to produce diacetates containing a smaller number of formaldehyde units. By controlling the time of reaction, the higher or lower molecular weight diacetates were made to predominate in the reaction mixture. Zine chloride can be used in place of sulfuric acid as the catalyst for the conversion of oxocanes to poly(oxymethylene diacetates). The reaction with ZnCl2 at room temperature is less vigorous and easier to control, yielding as the main product poly(oxymethylene diacetate) containing the same number of formaldehyde units as in the starting oxocane. |
