The investigation and optimization of the cinnamylated starch degree of substitution (DS) in basic media were carried out using a statistical approach based on the design of experiment (DoE) approach. An initial screening phase, conducted through a full factorial design, highlighted the following as the most critical parameters affecting the DS: (i) the base amount, (ii) the nature of the alkyl halide, (iii) the addition mode to the reaction mixture, and (iv) the equivalents used. The efficacy of different bases promoting the alkylation reaction was also studied, comparing sodium hydroxide, sodium alkoxides, and the dimsyl ion. Overall, the screening phase identified cinnamyl chloride and a sodium hydroxide DMSO dispersion as the optimal starting points for the optimization phase. The resulting model proved to be a robust tool for identifying optimal reaction conditions to achieve a high DS. The DoE statistical studies provided valuable insights into the mechanistic aspects and the complexity of the reaction system, extending beyond starch functionalization. These findings represent a significant advancement in the synthesis of starch-based materials, particularly for applications in the development of UV radiation-sensitive compounds, since they hold considerable potential across various industrial sectors.
Leuzzi et al. (Fri,) studied this question.