A Complementary and Revised View on the N-Acylation of Chitosan with Hexanoyl Chloride

The modification of the biobased polymer chitosan is a broad and widely studied field. Herein, an insight into the hydrophobization of low-molecular-weight chitosan by substitution of amino functionalities with hexanoyl chloride is reported. Thereby, the influence of the pH of the reaction media was...

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Bibliographic Details
Main Authors: Berthold Reis, Niklas Gerlach, Christine Steinbach, Karina Haro Carrasco, Marina Oelmann, Simona Schwarz, Martin Müller, Dana Schwarz
Format: Article
Language:English
Published: MDPI AG 2021-07-01
Series:Marine Drugs
Subjects:
Online Access:https://www.mdpi.com/1660-3397/19/7/385
Description
Summary:The modification of the biobased polymer chitosan is a broad and widely studied field. Herein, an insight into the hydrophobization of low-molecular-weight chitosan by substitution of amino functionalities with hexanoyl chloride is reported. Thereby, the influence of the pH of the reaction media was investigated. Further, methods for the determination of the degree of substitution based on <sup>1</sup>H-NMR, FTIR, and potentiometric titration were compared and discussed regarding their accuracy and precision. <sup>1</sup>H-NMR was the most accurate method, while FTIR and the potentiometric titration, though precise and reproducible, underlie the influence of complete protonation and solubility issues. Additionally, the impact of the pH variation during the synthesis on the properties of the samples was investigated by Cd<sup>2+</sup> sorption experiments. The adjusted pH values during the synthesis and, therefore, the obtained degrees of substitution possessed a strong impact on the adsorption properties of the final material.
ISSN:1660-3397