5.5 Mechanism of the chitin deacetylation

The reagent diffusion mechanism represents the second step in deacetylation of chitin. Recently, Sarhan et al. [28] have proposed a mechanism in which heterogeneous N-deacetylation is controlled by both reaction and diffusion: the first step involves the reaction of the onium salt, designated (Q<sup>+</sup> X), with NaOH to give the corresponding onium hydroxide (Q<sup>+</sup> OH�) capable of diffusing from the aqueous phase to the organic phase to start the deacetylation process by attacking the C = O of the acetyl group and then at the end of the reaction of hydrolysis, the resulting onium acetate (CH3COO�Q<sup>+</sup> ) will diffuse into the aqueous phase to be regenerated to a new onium hydroxide by the reaction with NaOH. From our results, the DD/ CNaOH ratios remain constant at each temperature at longer deacetylation times, which means that the deacetylation reaction is complete.
