Though the phase-separation system composed of the concentrated acid and p-alkylphenols, the lignin-based polymers (lignophenols) with the switching devices for the functionality control were synthesized. p-Substituted phenols grafted to C1 of the lignin side chain attacked C2 in alkaline media, followed by the cleavage of 2-O-aryl ether and the exchange of phenolic functionality from C1 phenols to lignin nuclei. Using 2,6-dimethylphenol (the control device), the switching functions of various ligno-p-alkylphenols were controlled. There was a good correlation between teh frequency of phenolic nuclei with C2-attackable OH and the depolymerization degree. Furthermore, compared with ligno-2,4-dimethylphenol, the rate of alkaline depolymerization fo ligno-p-n-propylphenol was lower, indicating that the switching functions of C1-grafted p-alkylphenols were affected to a larger extent by their steric factors rather than their electronegativity.
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