Furans are an important class of compounds that can be thermochemical or enzymatically produced from biomass. Despite of their importance little is known about the thermal decomposition of furans with oxygenated substituents. In this work, the influence of the -CH₃, -CH₂OH and -CHO functional groups on the molecular and radical decomposition chemistry is studied with a combined quantum chemical and experimental approach using 2-furfuryl alcohol and 5-methyl furfural as model components.

The quantum chemistry calculations show that both reactants can decompose by a ring-opening isomerization reaction and through carbene intermediates. The latter are formed by the shift of a hydrogen atom or a -CHO functional group within the furan ring structure. The -CHO functional group on the furan ring structure accelerates the molecular ring-opening isomerization reaction, while it suppresses carbene formation channels compared to other functional groups.

The weaker CH and CO bonds in 2-furfuryl alcohol and 5-methyl furfural compared to furan and furfural respectively result in a higher importance of radical chemistry that cannot be neglected. This is confirmed experimentally by analyzing the product spectrum with molecular beam synchrotron VUV photoionization mass spectrometry at a pressure of 0.04 bar and for temperatures between 923 K to 1223 K for 2-furfuryl alcohol and 973 K to 1273 K for 5-methyl furfural. For both reactants several radical intermediates are observed starting from 923 K for 2-furfuryl alcohol and from 973 K for 5-methyl furfural. Examples of measured radicals are those initial formed from the reactant by a CH homolytic bond scission and methyl, allyl, propargyl, 1,2-butadiene-4-yl, 2-furanyl-methyl, 2,5-dihydrofuran-2-yl and 1‑hydroxyl-2-furanyl-methyl radicals.

呋喃是一类重要的化合物，可以通过生物质进行热化学或酶法生产。尽管它们很重要，但对带有氧化取代基的呋喃的热分解知之甚少。本文结合量子化学和实验方法，以2-糠醇和5-甲基糠醛为模型，研究了-CH ₃，-CH ₂ OH和-CHO官能团对分子和自由基分解化学的影响。组件。

量子化学计算表明，两种反应物均可通过开环异构化反应和卡宾中间体分解。后者是通过氢原子或呋喃环结构内的-CHO官能团的移位而形成的。与其他官能团相比，呋喃环结构上的-CHO官能团可加快分子开环异构化反应，同时抑制卡宾形成通道。

与呋喃和糠醛相比，2-糠醇和5-甲基糠醛中较弱的C H和C O键分别导致不能忽略的自由基化学的重要性更高。通过分子束同步加速器VUV光电离质谱分析产物光谱，在0.04 bar的压力下，对于2-糠醇的温度在923 K至1223 K之间，对于5-甲基糠醛的温度在973 K至1273 K之间，通过实验分析了这一点。对于这两种反应物，观察到几种自由基中间体，对于2-糠醇，从923 K开始；对于5-甲基糠醛，从973 K开始。被测自由基的例子是由反应物通过C最初形成的自由基H均裂键断裂和甲基，烯丙基，炔丙基，1,2-丁二烯-4-基，2-呋喃基甲基，2,5-二氢呋喃-2-基和1-羟基-2-呋喃基甲基。