Multistage deacetylation of chitin: Kinetics study

In this work kinetic study of a high degree of deacetylated chitin, obtained from multistage deacetylation treatment is investigated. It is found that multistage alkali treatments are as effective as a single stage deacetylation treatment, and the product is more deacetylated. The influences of alkaline concentration, reaction temperature and time on the multistage deacetylation shrimp chitin are studied. The degree of deacetylation (DD) increased with increasing NaOH concentration, reaction temperature and time step of multistage treatment. The effect of NaOH concentration is significant; nevertheless; the effect of temperature is insignificant. Our results showed that the multistage deacetylation reaction followed the pseudo-first-order kinetics, and the apparent activation energy of single step treatment, compared with multistep deacetylation, is lower. The apparent rate constant of reaction ranged from 1.68 × 10−2 to 9.54 × 10−2 h−1 and the apparent activation energy is estimated 16.2 kJ/mol at the aqueous 50% NaOH solution, in temperature range of 70–90 °C.