Advances in the Chemistry of N-Containing Cross-Linking Agents

Abstract

A survey has been made of newly discovered relationships between chemical constitution and properties of well-known and new cross-linking agents for cellulosic fibers. Kinetic investigations into the cross-linking and hydrolysis of N- methylol and N-alkoxymethyl compounds have led to the discovery that the cleavage of the C-O- and the N-C- bonds is not subject to a specific, but to a general, acid catalysis; the mechanisms of these reactions are explained Apart from some special cases, the rate of cross-linking is defined by a linear relationship between the logarithms of the catalyst constant k _cat and the pK _A values of the acids used. The BrØnsted law of catalysis is valid for cross-linking. The rate constants of cross-linking are dependent on both the groups linked via oxygen as well as those linked via nitrogen. The rate constants of cross-linking are generally greater than those of cleavage of the N—C-bonds. Depending on the chemical constitution of the cross-linking agents, ditfierences in the rate constants of up to several powers of 10 were found for the reactivities. The condensations of X -methylol compounds with alcohols, as well as the hydrolysis of the N-alkoxymethyl compounds, are subject to states of equilibrium that are governed by temperature, molar ratio, concentration, solvent, and particularly by the chemical constitution of the cross-linking agents and the alcohol.