Related Experiment Video
Updated: Oct 3, 2026
Preparation of Expanded Chitin Foams and their Use in the Removal of Aqueous Copper
Published on: February 27, 2021
Relation between the degree of acetylation and the electrostatic properties of chitin and chitosan
P Sorlier1, A Denuzière, C Viton
1Laboratoire des Materiaux Polymères et des Biomatériaux (UMR-CNRS 5627), ISTIL, Domaine Scientifique de la Doua, 15 Boulevard Latarjet, 69622, Villeurbanne, France.
Abstract:
A series of chitosan/chitin samples with DA's varying between 5.2 and 89% was prepared from the reacetylation under soft conditions of a unique chitosan sample allowing the preservation of the chain distribution. The study of the variation of pH for the same concentration of amine groups, at different ionic strengths, on the scale of DA's allows us to extrapolate the variation of pKa at dissociation degrees (alpha) 0 and 1. A modeling of all the curves was obtained by means of only one equation. Then, for given concentration of chitosan and ionic strength, it is possible to predict the pH of the solution whatever the DA and alpha. The role of DA through the participation of hydrophobic interactions and hydrogen bondings on the electrostatic parameters is discussed. The results allow a better understanding of some physicochemical and biological properties of chitosan and chitin.
Related Concept Videos
01:31Substituent Effects on Acidity of Carboxylic Acids
02:42Acidity of 1-Alkynes
The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.
02:34Molecular Structure and Acidity
The size effect explains the change in atomic size on acidity. When comparing the acids formed from elements that belong to the same column in the periodic table, their atomic sizes...
01:28Structures of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
03:05Acid Strength and Molecular Structure
In the absence of any leveling effect, the acid strength of binary compounds of hydrogen with nonmetals (A) increases as the H-A bond strength decreases down a group in the periodic table. For group 17, the order of increasing acidity is HF < HCl < HBr < HI. Likewise, for group 16, the order of increasing acid strength is H2O < H2S < H2Se < H2Te. Across a row in the periodic table, the acid strength of binary hydrogen compounds increases with increasing...
01:13Relative Reactivity of Carboxylic Acid Derivatives
A key factor in assessing the reactivity of the acid derivatives is the basicity of the substituent or the leaving group. The lower the basicity of the leaving group, the higher the reactivity of the derivative. The basicity of the leaving group follows this order:
Halide ions < Acyloxy ions < Alkoxy ions < Amine ions