Figure 21.

Graphical representation of the steps of exhaustive acid hydrolysis (PTC₂/PTC₃), “sandwich model” under phase-transfer catalysis (PTC) of β-nonylphenoxypolyethyleneoxy (n=3-20) propionitriles [NF(EO)_nPN)] to β-nonylphenoxypolyethyleneoxy (n=3-20) propionic acids [NF(EO)_nPC)] Mathematical correlation of the experimental data enabled the generalization of a particular casuistry through mathematical relationships (linear, exponential, logarithmic and/or polynomial) correlation coefficients R² in the range 0.9-1. Thus are confirmed the reproducibility of the values recorded and the accuracy of the interpretations made.