The self-diffusion coefficient of sucrose in molasses, D-mol, has been dete
rmined via the pulsed-field-gradient C-13 NMR technique at 25, 50, 80, and
100 degreesC and a dry matter content of up to 80% w/w. For this purpose 10
% sucrose containing 99% 13C nuclei in the 1 position of the glucose moiety
was added. A comparison of D-mol with D-pure of pure aqueous solutions sho
wed D-mol < D-pure at the same sucrase water ratio. Viscosities of the mola
sses, <eta>(mol), and pure sucrose eta (pure) solutions were measured over
a wide range (1 mPa s to 5000 Pa s) and were shown to obey the empirical fo
rmula of Genotelle. The friction coefficient was found to be influenced by
the nonsucrose substances of the molasses, the value of the product D-mol e
ta mol being greater than that of D-pure eta pure at the same sucrose/water
ratio, with the deviation increasing with decreasing temperature and incre
asing concentration. The results have significant; consequences for the mod
eling of the technical crystallization process.