Synthesis, Characterization, Thermal Stability, and Kinetic Degradation of Cellulose p‐Halide Benzoates in an Ionic Liquid 1‐Butyl‐3‐methylimidazolium Chloride

Abstract

AbstractCellulose p‐halide benzoates (C‐p‐HB) were synthesized by reacting microcrystalline cellulose (MCC) with p‐halide benzoyl chloride (p‐HBCl) namely; the p‐Iodobenzoyl chloride (p‐IBCl), p‐Bromobenzyl chloride (p‐BBCl), and p‐Nitrobenzoyl chloride( p‐NBCl) in ionic liquid 1‐butyl‐3‐methylimidazolium chloride [Bmim](Cl) at 60 °C for 2 h in the presence of 4‐dimethylaminopyridine (DMAP) as a base. The synthetic products were characterized through infrared spectrometry (FT‐IR), nuclear magnetic resonance (NMR) spectroscopy, XRD, and scanning electron microscopy (SEM). Then, the effects of p‐halide benzoate groups on the thermal degradation of C‐p‐HB esters with DS≈1 were investigated using thermogravimetric analysis under an inert atmosphere from room temperature to 600 °C at a heating rate of 5 °C/min. The DSC analysis was used to determine the glass temperature and heat of the reaction of C‐p‐HB esters. The results indicated that the C‐p‐HB was successfully synthesized in [Bmim](Cl) with a DS≈1. The kinetic parameters were determined by the Coats‐Redfern (CR) method. The corresponding kinetic parameters of the main degradation stages were also determined. The thermal stability of MCC was remarkably decreased through esterification with p‐HBCl. The Criado method was used to determine the most probable degradation functions. Thus, reaction orders F2 and F3 were most probably the functions that describe the degradation of C‐p‐HB.