Limonene is the most abundant terpene in citrus byproducts, such as lemon and orange peels. Due to its six-membered ring structure, it is considered a valuable feedstock for the synthesis of important bioaromatics, such as p-cymene. This study aims to develop a rapid and sustainable method to produce bio p-cymene from biomass-derived limonene. The use of enabling technologies, such as microwaves (MWs), can significantly intensify the process, leading to further improvements in sustainability. Several mono- and multimode MW reactors have been tested in this context. Monomodal systems have yielded the highest p-cymene output (up to 22.61% selectivity), while multimode reactors allow for a scaling-up approach that overcomes the limitations of the monomodal ovens while still providing noticeable p-cymene yields (up to 17.79%). An environmentally friendly protocol that utilizes mild temperatures (80–165 °C), has reduced time requirements (0–5 min), and can be performed in solvent-free conditions was employed throughout the process. This approach makes use of a wide range of biorefinery-based practices and is aligned with green processing, the circular economy, and process intensification principles.

中文翻译：

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利用柠檬烯可持续微波辅助生物对伞花烃生产的工艺强化

柠檬烯是柠檬和橙皮等柑橘副产品中最丰富的萜烯。由于其六元环结构，它被认为是合成重要生物芳烃（例如对伞花烃）的宝贵原料。本研究旨在开发一种快速且可持续的方法，从生物质衍生的柠檬烯中生产生物对伞花烃。使用微波（MW）等使能技术可以显着强化这一过程，从而进一步提高可持续性。在这方面已经测试了几种单模和多模MW反应堆。单峰系统产生了最高的对伞花烃产量（高达 22.61% 选择性），而多模式反应器允许采用放大方法，克服单峰炉的局限性，同时仍然提供显着的对伞花烃产量（高达 17.79%） 。整个过程采用了一种环境友好的方案，该方案利用温和的温度（80-165°C），减少了时间要求（0-5分钟），并且可以在无溶剂条件下进行。这种方法利用了广泛的基于生物精炼的实践，并符合绿色加工、循环经济和工艺强化原则。