Abstract Three different bio-based styrene monomer alternatives, i.e., 4-vinylphenol derivatives, were synthesized starting from lignin building blocks. The synthetic route encompassed a green Knoevenagel condensation followed by two decarboxylation steps and acetylation. High isolated yields for the decarboxylation were obtained in a polar aprotic solvent, which prevented oligomerization. The polymerization of the three acetylated 4-vinylphenols was performed by free radical polymerization. The chain transfer constants of styrene and 4-acetoxy styrene 4c in toluene were evaluated in the Mayo procedure using the number-average molecular weight (Mn). After polymerization, the acetoxy group of the different polymers was efficiently hydrolyzed. The resulting phenol side groups of these polystyrene alternatives provide future opportunities to functionalize these bio-based polymers further.

中文翻译：

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生物基苯乙烯替代品的制备及其自由基聚合

摘要 以木质素构件为原料合成了三种不同的生物基苯乙烯单体替代品，即 4-乙烯基苯酚衍生物。合成路线包括绿色 Knoevenagel 缩合，然后是两个脱羧步骤和乙酰化。在极性非质子溶剂中获得了脱羧的高分离产率，这阻止了低聚。三种乙酰化 4-乙烯基苯酚的聚合是通过自由基聚合进行的。在 Mayo 程序中使用数均分子量 (Mn) 评估苯乙烯和 4-乙酰氧基苯乙烯 4c 在甲苯中的链转移常数。聚合后，不同聚合物的乙酰氧基被有效水解。