The preparation of vanillin from lignin is one of the lignin valorization strategies. However, obtaining high vanillin yield is still a challenge. Therefore, the process of vanillin production and factors that affect yield of vanillin has attracted much attention. Here, oxidation of vanillin was performed to study its degradation behavior under lignin alkaline oxidation conditions. High-performance liquid chromatography, liquid chromatography–electrospray mass spectrometry, gas chromatography–mass spectrometer and gel permeation chromatography were employed to analyze the products including monomers and dimers. Results demonstrated that reaction temperature and time greatly affected vanillin degradation; vanillin can be completely converted in 5 h at 160 °C. At 160 °C, the main products of vanillin oxidation were small molecule acids and alcohols, other monophenols, and even condensed dimers. A possible vanillin degradation pathway was proposed. The results indicate that vanillin degradation and condensation are the main reasons for decreasing vanillin yield during lignin valorization under alkaline oxidation circumstances.

由木质素制备香兰素是木质素增值策略之一。然而，获得高香草醛产量仍然是一个挑战。因此，香兰素的生产过程和影响香兰素产量的因素已引起广泛关注。在这里，进行香兰素的氧化以研究其在木质素碱性氧化条件下的降解行为。高效液相色谱，液相色谱-电喷雾质谱，气相色谱-质谱和凝胶渗透色谱法用于分析包括单体和二聚体在内的产物。结果表明，反应温度和时间对香兰素的降解有很大影响。香兰素可以在160°C下5小时内完全转化。在160°C时，香兰素氧化的主要产物是小分子酸和醇，其他单酚，甚至是缩合二聚体。提出了一种可能的香兰素降解途径。结果表明，在碱性氧化条件下木质素增值过程中，香草醛的降解和缩合是降低香草醛产量的主要原因。