In this work, we report for the first time, the tungstic acid-catalyzed oxidation of terpene alcohols with hydrogen peroxide. This simple, solid, and commercially available catalyst efficiently promoted the conversion of borneol, geraniol and nerol to camphor and epoxide products, respectively. Effects of main reaction parameters, such as catalyst load, the molar ratio of oxidant to the substrate, time, and reaction temperature were investigated. Conversions and selectivity greater than 90% were achieved using 1.0 mol % of H₂WO₄ after 2 h of reaction at 90 °C. The activation energy was equal to 66 kJmol⁻¹. We propose a reaction mechanism based on the experimental results. This solid catalyst was easily recovered and reused without loss of activity. As far as we know, it is the first time that tungstic acid was used as the catalyst in the oxidation reactions of terpene alcohols.

Graphical Abstract

中文翻译：

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钨酸：一种简单有效的固体催化剂用于萜烯醇与过氧化氢的氧化反应

在这项工作中，我们首次报道了钨酸催化的萜烯醇与过氧化氢的氧化反应。这种简单、固体且可商购的催化剂有效地促进了冰片、香叶醇和橙花醇分别向樟脑和环氧化物产品的转化。研究了催化剂负载量、氧化剂与底物的摩尔比、时间和反应温度等主要反应参数的影响。在 90 °C 下反应 2 小时后，使用 1.0 mol% 的 H ₂ WO ₄实现了大于 90% 的转化率和选择性。活化能等于 66 kJmol ^-1. 我们根据实验结果提出了一种反应机制。这种固体催化剂很容易回收和重复使用而不会损失活性。据了解，钨酸作为催化剂用于萜烯醇的氧化反应尚属首次。

图形概要