Abstract
The physicochemical characteristics of chitosan differ with the preparation conditions. Thus, it is necessary to control the different parameters which influence the N-deacetylation reaction so as to produce chitosan with the characteristics required by its final applications. Samples of α-chitin used in this report were obtained from Snow crab (Paralomis granulosa) and King crab (Lithodes antarcticus). These species are not commonly used in the production of chitosan, making it important to find the proper conditions for the reactions involved. After careful study of several different N-deacetylation conditions [80°, 90°, 100°, 110°C and 30%, 50%, 60%, 70% (w/v) of sodium hydroxide solution], it was demonstrated that, in the case of these species, 110°C was the most effective temperature under heterogeneous conditions at least for the first 10 minutes of the reaction. Also, a nitrogen environment to reduce the degradation of the polymer during the reaction was more effective than other methods proposed in the literature. Finally, use of 70% (w/v) sodium hydroxide solution let us obtain soluble products in the first minutes of the reaction without causing much degradation.