N-Methylmorpholine-N-oxide ring cleavage registration by ESR under heating conditions of the Lyocell process

Abstract

Thermal cleavage processes of N-methylmorpholine-N-oxide monohydrate (NMMO) were observed in pure NMMO as well as in cellulose/NMMO solutions by ESR at temperatures of the industrial Lyocell process (∼370 K). Generated radicals were attributed to the alkylnitroxyl type radicals -CH2-NO{radical dot}-CH3 in NMMO and additional (and dominated) -CH2-NO{radical dot}-CH2- in cellulose/NMMO solutions. Formation of both radical types formed due to NMMO ring scission is suggested. © 2007 Elsevier B.V. All rights reserved.