Relationships Between Acidity Functions, Rates of Reactions of Formaldehyde with Cellulose and of Cellulose Hydrolysis. 28th communication on investigations in textile chemistry

Abstract

Summary. The rates of hydrolysis of cellulose and the rates of formation of cellulose formal were measured in heterogeneous systems consisting of cotton cellulose and solutions of formaldehyde in aqueous hydrochloric acid and in solutions of hydrochloric acid in various waterlacetic acid mixtures. The rates were related to the acidity functions (H,) of the solutions. Although fairly good linear relationships between the logarithms of the rates and H, were obtained In most cases, no conclusions concerning the reaction mechanism could be drawn.

Acidities of Hydrochloric Acid in Water/Acetic Acid and in Water/Acetic Acid/Formaldehyde Mixtures: Investigations with the indicator method and with the nmr method. 31st communication on investigations in textile chemistry

“…Therefore, it became even more interesting than anticipated and discussed briefly in the introduction of this investigation, to compare (H,)I and b~ (measured in presence of CH,O) with our previous measurements of the rate of formal lormation of cellulose [3]. Using the rate constants k,, determined for formal formation in aqueous systems in the previous paper [3b] and the (H0)1 and BH values of this investigation, one gets the relations given in Fig.…”

“…57, Fssc. 3 (1974) In the prcvious communication [3] we rcported also on the rate of depolymerisation (hydrolysis) of cellulose in aqueous hydrochloric acid solutions containing forrnaldchyde, based on (H,) I measurements in formaldehyde-free solutions. h logarithmic plot of the rate constant khy versus (H,)r (without formaldehyde) yielded alinear relationship (r = 0.936).…”

“…For further details see also [3]. Formation of such compounds would of course complicate the use of these aniline derivatives mentioned as indicators.…”

“…In a previous paper [3] we demonstrated for water/hydrochloric acid systems that the logarithms of the rate of formal formation are proportional to the negative values of Harnmett's acidity function, H,.…”

“…-We are interested in the acidities of mineral acids in various water/acetic acid/formaldehydc systems because they are used as media for crosslinking cellulose, particularly in cotton fabrics [a] [ 3 ] . We showed that the overall process is complex and, depending on rcaction conditions, different partial processes may become rate-limiting [a].…”