Reaction Mechanisms of Glyoxal-Based Durable-Press Resins with Cotton

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Abstract
Leaving-group and other effects in acid-catalyzed nucleophilic substitution reactions with a number of 4,5-disubstituted ethyleneureas, 1,3-disubstituted ethyleneureas, and N-substituted methyl carbamates are considered. Acetoxy and secondary alkoxy leaving groups enhance reactivity from formaldehyde-hased (primary carhonium ion formed) systems hut not from glyoxal-based (secondary carhonium ion formed) systems. The 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) molecule, for best reaction with cotton or other nucleophiles should be activated by selected leavint; groups on the methylenes in the 1,3-positions, but not necessarily in the 4,5-positions. Reactivity to small nucleophiles of 1,3- and 4,5-positions in DMDHEU systems are equal when leaving groups are hydroxy or methoxy. Ring (4,5-) positions are hindered. Other factors which influence reactivity or carhonium-immonium ion stability in DMDHEU are discussed. Evidence is presented which suggests that anhydroglucose units in cellulose possess groups of different leaving ability which will influence the location and durability of agents reacted with cellulose. Implications of these findings on the finishing of cotton cellulose are discussed.