The number of reducing end of carboxymethylcellulose (CMC) produced in thedifferent solvents has been experimentally determined by potentiometry after completeenzymic degradation or acid hydrolysis．Parameters relating to the distribution of substituent along CMC chain

such as the average length of substituted or unsubstitutedanhydroglucose units (AGU)

the percentage of monosubstituted or disubstituted units

etchave been calculated

and the resistance to acid of these CMC was studied．It shows thatthe solvents are dosely telated to this distribution of substituent．Also

the effect of differ-ent compositions of i—propanol/water on the distribution of substitufion of CMC hasbeen studied．When the content of i—propanol changed from 75％ to 95％

it was foundthat the degree of substitution of CMC increases

and that the uniformity of the distritufionof substitution iS better with the increasing concentration of i—propanol.