Valorization of pyrolytic lignin to fuels and chemicals is still poorly understood due to its ill-defined structure and the complexity of the decomposition chemistry. To shed some light on the dominant reaction pathways of lignin thermolysis, novel experimental and first-principles based calculations of its building blocks have been carried out. Pyrolysis chemistry of hydroxycinnamic acids is investigated in this work using a unique Py-GC × GC-FID/TOF-MS coupled with a customized GC to detect water and gases, to gain an understanding of the role of the branching ratios in lignin and its linkages with hemicellulose. Mean residence times of cinnamic and ferulic acids were estimated to be 12 and 21 s at 573 K, based on time-resolved experiments. Cinnamic acid undergoes a CO₂ elimination reaction at temperatures higher than 873 K without an intermediate liquid phase. At temperatures as low as 573 K, –OH and –OCH₃ substituted cinnamic acids underwent decarboxylation despite bearing similar BDEs for Cβ–Cγ scission. At these temperatures, p-coumaric and ferulic acids were converted into 4-vinylphenol and 4-vinylguaiacol by 40 wt% and 30 wt%, respectively. On the other hand, sinapinic acid converted nearly by 80 wt% at temperatures below its boiling point of 676 K. In conjunction with novel quantum chemical calculations, it could be ruled out that decarboxylation was not occurring via concerted unimolecular reactions at low temperatures. Instead, water-catalyzed reactions of hydroxycinnamic acids seem to be the primary cause for the CO₂ elimination in the intermediate liquid phase via a 6-centered transition state.

由于热解木质素的结构不明确以及分解化学的复杂性，人们对热解木质素在燃料和化学品中的价位了解仍然很少。为了阐明木质素热解的主要反应途径，已经进行了基于新的实验和第一性原理的木质素构建单元的计算。在这项工作中，使用独特的Py-GC×GC-FID / TOF-MS和定制的GC来检测水和气体，从而研究了羟基肉桂酸的热解化学，以了解木质素及其分子中支化比的作用。与半纤维素的联系。根据时间分辨实验，肉桂酸和阿魏酸的平均停留时间在573 K下估计为12和21 s。肉桂酸经历了CO ₂在没有中间液相的情况下，在高于873 K的温度下进行消除反应。在低至573 K的温度下，–OH和–OCH ₃取代的肉桂酸经历了脱羧，尽管Cβ–Cγ断裂具有相似的BDE。在这些温度下，对香豆酸和阿魏酸分别以40重量％和30重量％转化为4-乙烯基苯酚和4-乙烯基愈创木酚。另一方面，芥子酸在低于其沸点676 K的温度下转化了将近80 wt％。结合新颖的量子化学计算，可以排除脱羧不是在低温下通过协同的单分子反应而发生的。相反，羟基肉桂酸的水催化反应似乎是CO _2的主要原因。 在中间液相中通过6中心过渡态消除。