Darstellung eines reinen monomeren formaldehyds durch acidolytische depolymerisation von Trioxan. 22. Mitt. über polyoxymethylene¹

Abstract

ZUSAMMENFASSUNG:Trioxan wird mit nahezu quantitativem Umsatz kontinuierlich in einem Stickstoffstrom bei 200 "C an einem Pyrophosphorsaure-Kontakt zu monomerem Formaldehyd depolymerisiert. Durch Vorpolymerisation von ca. 5 yo des gasformigen Formaldehyds werden die geringfiigigen Verunreinigungen wie Methylformiat, Wasser und unumgesetztes Trioxan entfernt, so da13 das restliche Monomere eine Reinheit von mindestens 99,98y0 besitzt. Losungen dieses Formaldehyds in Toluol oder Diathylather zeigen zwischen -78 und -50°C eine sehr gutc Haltbarkeit. SUMMARY:Trioxane is depolymerized almost quantitatively to form monomeric formaldehyde in a flow system at 200 "C. using pyrophosphoric acid as catalyst and h o g e n as a carrier gas.By prepolymerizing of 5 yo of the gaseous formaldehyde impurities such as methyl formate, water or unconverted trioxane are removed so that the rest of the monomer is more than 99.98% pure. Solutions of this formaldehyde in toluene or in ether show a very good stability between -78 and 50°C.

Alternative Liquid Fuels from Renewable Resources

“…Monomeric formaldehyde is a highly reactive species and tends to polymerize immediately in the presence of water. On lab scale, it can be synthesized by catalytic decomposition of trioxane , or paraformaldehyde , . The dehydrogenation of methanol was discussed as a direct and highly efficient synthesis pathway for monomeric formaldehyde.…”