Isotope labeling-based studies on the pyrolysis of dimeric β-O-4 lignin model compounds phenylethyl phenyl ether and phenylethanol phenyl ether

作者：Zhenzhen He, Peiqi Chen, Gang Li, Bo Lei, Kui Xiang, Yaolong Li, Jie Shao, Mengna Yang, Xiang Han, Anning Zhou, Qiuhong Wang, Fuxin Chen · 发表于：Journal of Analytical and Applied Pyrolysis · 年份：2025 · DOI：10.1016/j.jaap.2025.107103 · 被引用次数：7 · 研究领域：Lignin and Wood Chemistry、Fermentation and Sensory Analysis、Enzyme-mediated dye degradation

In this study, the pyrolysis of the β-O-4 lignin model compounds phenylethyl phenyl ether (PPE) and phenylethanol phenyl ether (PEPE) in the presence of H 2 O, D 2 O and H 2 18 O at 500°C was investigated. The pyrolysis products were examined by GC-MS to analyze the pyrolysis process and product formation mechanisms. By comparing the pyrolysis products of PPE and PEPE, the chemical structure effect of C α -OH was found to decrease the yield of styrene, benzaldehyde, and phenylethanol, while increasing the yield of acetophenone, which facilitated the decomposition of C β -O and led to an increase of the phenol yield. Analysis of the isotope-labeled PPE pyrolysis products revealed that phenol undergoes deuteration to varying degrees, and the deuterated intermediates undergo intramolecular exchanges to produce deuterium-substituted phenols (C 6 H 5 OD, C 6 H 4 DOH, C 6 H 4 DOD), which verified the presence of the reciprocal isomer 2,4-cyclohexadienone. The product acetophenone from the pyrolysis of PEPE was deuterated to varying degrees, indicating multiple pathways of formation, which was accompanied by the formation of phenol, resulting in a high abundance of acetophenone and phenol products. Phenylethanol was found to be an important intermediate in the formation of phenylacetaldehyde. The order of occurrence of the different reaction intermediates of PPE and PEPE was hypothesized and the free radical reaction was found to play a dominant role. This experiment reveals the evo...