The condensation reaction of lignin is believed to interfere with delignification in alkaline pulping processes, without any clear evidence, which has motivated us to quantitatively revisit it. This paper is the first of a series, and hence we employed the simplest model system using 4-hydroxymethyl-2-methoxyphenol (vanillyl alcohol, Va) and 2-methoxy-4-methylphenol (creosol, Cr) under soda cooking conditions. The α-5-type condensation product between these compounds [VaCr, 2-(4-hydroxy-3-methoxybenzyl)-6-methoxy-4-methylphenol] was identified and quantified as exclusive. VaCr was yielded with a mole amount of 24%, 46%, 62%, or 72% based on that of disappearing Va at a reaction time of 120 min when the ratio of the initial concentration of Cr to that of Va was 1.0, 2.5, 5.0, or 7.5, respectively. These yields and an HPLC analysis of the reaction solution obtained by a treatment of Va as the sole compound under the same soda cooking conditions suggested the formation of self-condensation products of Va even in the treatments containing Cr. The obtained results comprehensively suggested that the self-condensation of Va progresses more readily than the condensation between Va and Cr. The factors behind this will be the topic of our next paper.

中文翻译：

---

定量重温碱性制浆中木质素的缩合反应第一部分：苏打蒸煮条件下香草醇和甲酚之间最简单的缩合反应

木质素的缩合反应被认为会干扰碱性制浆过程中的脱木质素，但没有任何明确的证据，这促使我们对它进行定量重新审视。本文是系列文章中的第一篇，因此我们采用了最简单的模型系统，在苏打蒸煮条件下使用 4-羟甲基-2-甲氧基苯酚（香草醇，Va）和 2-甲氧基-4-甲基苯酚（甲酚，Cr）。这些化合物之间的α-5-型缩合产物[VaCr，2-(4-羟基-3-甲氧基苄基)-6-甲氧基-4-甲基苯酚]被鉴定并量化为排他性。当 Cr 的初始浓度与 Va 的初始浓度之比为 1.0、2.5 时，基于在 120 分钟的反应时间中消失的 Va，产生的 VaCr 的摩尔量分别为 24%、46%、62% 或 72% 、 5.0 或 7.5，分别。这些收率和通过在相同苏打蒸煮条件下处理作为唯一化合物的 Va 获得的反应溶液的 HPLC 分析表明，即使在含有 Cr 的处理中也形成了 Va 的自缩合产物。所得结果综合表明，Va 的自缩合比 Va 和 Cr 之间的缩合更容易进行。这背后的因素将是我们下一篇论文的主题。