Abstract:
The present work deals with the study of the process,
parameters such as alkali concentration for steeping, reaction
time, maturing time and reaction temperature for the preparation
of sodium carboxymethyl cellulose (SCMC) for obtaining the
optimum conditions for commercial application.
Experiments were carried out both in aqueous and ethanolic
media. On the basis of the experiments carried out 'using glass
wares, a.stainless steel stirred cylindrical reactor was used to
study the process using a cellulose mass of 50 gm in each batch.
Alkalization or steeping was carried out at different alkali
concentrations and the suitable concentration to obtain
stoichiometric amount of consumption of alkali was ,found to be
18%. Temperature in the range 25-30°C and reaction time for 2
hours were found to be optimum for steeping operation. Maturing
time after steeping was established at 12-16 hours. The most
suitable conditions for carboxymethylation were reaction
temperature = 40 to 45~C; reaction time = 8 hours; and maturing
time = 18 to 20 hours.
Optimization of the use of reactants was obtained by
recycling the reactants and alcohol. The use of make-up reactants
decreased with the increase of the number of batches in a cycle.
i
Alcohol recovery was also improved to 87%.
Not all SCMCs produced were soluble in water. Degree of
Substitution (DS) varied in the range of 0.69-0.99. Viscosities
of 1% and 2% solutions were in the ranges of 7.16-262 centipoise
and 35.0 - 2110 centipoise respectively. Water solubility, DS
values and solution viscosities of the products indicate that the
SCMCs obtained were of commercial quality.
