Hubei Provincial Key Laboratory of Green Materials for Light Industry, Hubei University of Technology, Wuhan 430068, China.
State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China.
Sci Total Environ. 2022 Sep 10;838(Pt 3):156395. doi: 10.1016/j.scitotenv.2022.156395. Epub 2022 Jun 2.
It is anticipated that the insight into the demethylation and mechanism of CH formation from natural lignin using in-situ diffuse reflectance infrared Fourier transform spectroscopy (in-situ FTIR) combined with two-dimensional perturbation correlation infrared spectroscopy (2D-PCIS) and density functional theory (DFT) calculation analysis would contribute to a deeper insight of bond cleavage mechanism of lignin pyrolysis. Herein, GS-type lignin (poplar MWL) was characterized by Fourier transform infrared spectroscopy (FTIR) and heteronuclear Single-Quantum Correlation Nuclear Magnetic Resonance (HSQC), and its pyrolysis at different temperatures was performed in a lab-scale fixed-bed reactor. The biochar, gaseous and liquid products were qualitative, and quantitative analysis of gases and bio-oil is demonstrated using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The key of CH formation is the homolytic cleavage of the methoxyl functional group generating methyl radical and further verified via in-situ FTIR combined with 2D-PCIS and DFT calculation. The study established a new methodology based on multiple factor analysis to evaluate the CH formation mechanism in GS-type milled wood lignin at the molecular level, which is of positive significance for increasing lignin valorization and improving the environment.
预计使用原位漫反射红外傅里叶变换光谱（in-situ FTIR）结合二维扰动相关红外光谱（2D-PCIS）和密度泛函理论（DFT）计算分析，从天然木质素中了解 CH 形成的去甲基化和机制，将有助于深入了解木质素热解的键断裂机制。在此，通过傅里叶变换红外光谱（FTIR）和异核单量子相关核磁共振（HSQC）对 GS 型木质素（杨木 MWL）进行了表征，并在实验室规模的固定床反应器中在不同温度下对其进行了热解。对生物炭、气态和液态产物进行了定性分析，并使用气相色谱（GC）和气相色谱-质谱（GC-MS）对气体和生物油进行了定量分析。CH 形成的关键是甲氧基官能团的均裂，生成甲基自由基，并通过原位 FTIR 结合 2D-PCIS 和 DFT 计算进一步验证。该研究建立了一种基于多因素分析的新方法，用于在分子水平上评估 GS 型磨碎木木质素中 CH 形成的机制，这对于提高木质素的附加值和改善环境具有积极意义。
