Specific phenomena during the copolymerization of trioxane and ethylene oxide

Abstract

We, at Asahi Chemical in Japan, have industrialized three types of polyacetal resins, that is, the acetal homopolymer, copolymer and block copolymer using anionic, cationic and anionic polymerization techniques, respectively. During this industrialization, we observed various phenomena, which were not previously reported. First, the authors outline the three technologies for producing each type of polyoxymethylene from an industrial viewpoint. Next, the authors discuss a newly found reaction during the induction period of the trioxane and ethylene oxide copolymerization. Experimental proof of direct ring expansion between the reaction of trioxane and ethylene oxide is discussed and various novel cyclic compounds are also shown. To the best of our knowledge, this reaction may be the world's first experimental proof of direct ring expansion of the reaction of a cyclic monomer. Third, the authors also discuss the newly founded morphospecific polymer from the copolymerization of trioxane and ethylene oxide using boron trifluoride dibutyl ether as an initiator.

A Novel Branched Polyoxymethylene Synthesized by Cationic Copolymerization of 1,3,5‐Trioxane with 3‐(Alkoxymethyl)‐3‐ethyloxetane

“…[ 2 ] A common method that has been industrialized is the end-capping reaction of the terminal hemiacetals with acetic anhydride; however, the end-capping process is very energy-intensive, requiring high reaction temperature (≈170 °C) due to the poor solubility of POM. [ 3,4 ] The other way to improve the thermal stability of POM is by copolymerizing of 1,3,5-trioxane (TOX) with cyclic ethers such as ethylene oxide, [5][6][7][8][9] 1,3-dioxolane, [10][11][12][13] 1,3-dioxepane, [ 14 ] and 1,3-dioxep-5-ene. [ 15 ] The random introduction of −[(CH 2 ) n −O] ( n ≥ 2)− units limits the unzipping of the chain and improves the thermal stability of the −(CH 2 −O) n − units in the copolymer.…”

Acetal Copolymer from the Copolymerization of Trioxane and Ethylene Oxide

“…The new method for the synthesis of trioxane will be reported soon . The extracted trioxane was purified by distillation according to the method described in our patents. , The water content in the purified trioxane was below 1 ppm. Methylal, which was used as the chain-transfer agent, was dehydrated by using 4A molecular sieves.…”

Polyoxymethylenes

“…The formox or silver catalyst process is usually used; see also [51]. The Asahi process, in which formaldehyde is prepared by oxidation of methylal rather than methanol [52] leads to higher formaldehyde concentrations [53].…”