The Dyeing of Cellulose Acetate with Non‐ionic Dyes

The heats of dyeing of five “model” dyes on cellulose acetate have been meeaured. By combining these with the heats of solution and sublimation of the dyes, the absolute heats of association between dyes and substrate may be evaluated. This has been done for the two dyes for which data on heats of sublimation are available; values of the order of ‐ 20 kcal./mole are obtained. The bond energies appear to be chiefly ascribable to interaction between the permanent dipoles of the carbonyl groups in the substrate and permanent or induced dipoles in the dye molecules. There ere indications in the two cases examined that, if intermoleculer hydrogen bonds exist in the dye crystals, then hydrogen bonds may reasonably be postulated also between the dyes and the substrate.