Expedient synthesis and properties of 6-deoxy-6-amino chitosan.

Chitin and chitosan play an important role in the context of a biorefinery where waste is converted into useful products. The introduction of an amine at the C-6 position of chitosan has led to the synthesis of a water-soluble chitosan derivative, 6-deoxy-6-amino chitosan. However, all known synthetic methods for the synthesis of 6-deoxy-6-amino chitosan have some limitations, which acts as impediments to the scale up process and ultimately exploitation. The solubility of the polymer in water is advantageous and opens many different avenues of application. A shorter and scalable synthetic pathway was sought due to the prior use of hazardous solvents and the generation of large quantities of waste. To aid the modification of chitin and chitosan, a model study on the glucosamine monomer was utilised. An innovative synthetic means of introducing an amine at C-6 position of the biopolymer was achieved. Ultimately, this expedient synthesis of 6-deoxy-6-amino chitosan resulted in a much-improved yield and quality of 6-deoxy-6-amino chitin and chitosan. Additionally the synthesis of an alkylamino derivative was also considered. The antimicrobial properties of the improved synthetic chitosan derivatives was evaluated and compared against material prepared from prior synthetic routes.

Chitosan derivatives as important biorefinery intermediates. Quaternary tetraalkylammonium chitosan derivatives utilized in anion exchange chromatography for perchlorate removal.

There has recently been great interest in the valorization of biomass waste in the context of the biorefinery. The biopolymer chitosan, derived from chitin, is present in large quantities of crustacean waste. This biomass can be converted into value-added products with applications in energy, fuel, chemicals and materials manufacturing. The many reported applications of this polymer can be attributed to its unique properties, such as biocompatibility, chemical versatility, biodegradability and low toxicity. Cost effective water filters which decontaminate water by removal of specific impurities and microbes are in great demand. To address this need, the development of ion exchange resins using environmentally friendly, renewable materials such as biopolymers as solid supports was evaluated. The identification and remediation of perchlorate contaminated water using an easy, inexpensive method has come under the spotlight recently. Similarly, the use of a low cost perchlorate selective solid phase extraction (SPE) cartridge that can be rapidly employed in the field is desirable. Chitosan based SPE coupled with colorimetric analytical methods showed promise as a renewable anion exchange support for perchlorate analysis or removal. The polymers displayed perchlorate retention comparable to the commercial standard whereby the quaternized iron loaded polymer TMC-Fe(III) displayed the best activity.