4082-91-1Relevant articles and documents
Reaction pathways at the initial steps of trioxane polymerisation
Hoffmann, Matthias,Bizzarri, Claudia,Leitner, Walter,Müller, Thomas E.
, p. 5594 - 5603 (2018/11/20)
Cleavage and (re)formation of oxymethylene moieties are essential steps during the build-up of polyoxymethylene (POM), a technically relevant high-performance polymer. To reveal how the catalyst accomplishes the cleavage of oxymethylene moieties, the kinetics of the ring-opening of trioxane was studied. Thereby insights into the initial phase of the growth of oxymethylene chains were obtained. The chain length of short oligomers was controlled with acetic anhydride as transfer agent. With a high ratio of acetic anhydride to trioxane, the first homologues of the series, trioxymethylene diacetate, dioxymethylene diacetate and monooxymethylene diacetate were obtained in excellent yield. The homologues show distinct features in the NMR and IR spectra that were related to their reactivity during chain propagation. Formation of intermediate hemi-acetal oxonium moieties is suggested to be a key step in the reaction pathway. Such molecular level insight may be a crucial factor for further tailoring production and properties of polyoxymethylene as well as introducing oligomeric oxymethylene diacetates to new application fields.
Observation of bromomethyl ethers during the bromomethylation of aromatic compounds
St. Clair, Jerry D.,Valentine, James R.
, p. 1013 - 1014 (2012/12/26)
A literature method claiming to avoid the generation of highly toxic intermediates during bromomethylation of aromatic compounds was investigated. Gas chromatography revealed that such toxic intermediates may be present in the reaction mass in significant concentration. Indeed, these intermediates can be the major components under certain reaction scenarios. It is thus inaccurate to consider this chemistry free of hazardous intermediates. These potential hazards should be considered in any laboratory or scale-up implementation of this chemistry.
