Thermodynamic analysis of cellulose nitration
Designer Energy Ltd, 2 Bergman Str., Rehovot 7670504, Israel.
Research Article
World Journal of Advanced Research and Reviews, 2024, 21(03), 485–494
Publication history:
Received on 21 January 2024; revised on 04 February 2024; accepted on 06 February 2024
Abstract:
In this study, the standard formation enthalpies and entropies of cellulose and nitrocellulose samples were determined. These characteristics were used for thermodynamic analysis of bulk nitration of the entire cellulose sample and local nitration only of amorphous domains (ADs) of cellulose. It was found that the reaction of bulk nitration of cellulose up to a substitution degree (DS) of 1.5 is endothermic and determined primarily by the contribution of the temperature-entropy component to the negative Gibbs potential. However, if DS is higher than 1.5, the bulk nitration becomes exothermic and its feasibility is determined by the impact of enthalpy on the Gibbs potential. In the case of local nitration of cellulose ADs, the main contribution to the Gibbs potential is made by the reaction enthalpy that determines the feasibility of this process. It was shown that with the enhancement in DS of nitrocellulose, the negative value of the Gibbs potential of the reaction increases. Thus, the cellulose nitration to higher DS is thermodynamically favorable. Since the locally nitrated samples are copolymers of amorphous nitrocellulose and crystalline cellulose, they should be significantly less hydrophilic than cellulose. Therefore, it can be expected that the local nitration method will find a wide practical application for inexpensive hydrophobization of cellulose materials.
Keywords:
Cellulose nitration; Bulk nitration; Local nitration; Nitrocelluloses; Degree of substitution; Thermodynamic functions; Thermodynamical analysis
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