Recovery of chemicals from sugar in supercritical fluids for oligochemistry cycle

我们研究了超临界水中糖的化学回收，重点是乙二醇酸作为一种可生物降解的材料。本研究考察了回收乙二醇醛的工艺条件。首先，利用微型反应器分析了乙二醇的分解过程。通过逆醛醇缩合反应，甘油醛分解为赤藓糖和乙二醇醛。乙二醇醛通过互变异构转化为果糖，最后分解为甘油醛和异戊醛。这些反应都伴随着脱水，我们估算了反应速率及其对温度的依赖性，发现较高的温度和较低的水浓度促进了逆醛醇反应，而不是脱水和互变异构。在450℃下，在密度为0.1g/cm ~ 3的水中反应生成乙二醇酸，产率为89%。我们还证实了乙二醇醛通过Cannizzaro反应生成乙二醇酸，反应速率估计为几十毫秒，这表明需要小型反应器才能实现工业化过程。研究表明，乙二醇酸的转化反应条件、工业浓缩反应物的反应和其他工业热量的利用是今后的研究方向。

We investigated chemical recycling from sugar in supercritical water, focusing on glycol acid as a biodegradable material. In this research, process conditions are surveyed to recover glycol aldehyde.First of all, we analyzed decomposition process of glycol using micro-reactors. Glycols decomposed to erythrose and then glycol aldehyde by retroaldol reaction. Glycol aldehyde is converted info fructose by tautomerism and finally decomposed into glyceraldehyde and pyruvaldehyde. These reactions were accompanied with dehydration.We estimated the reaction rate and its dependency on temperature and revealed that higher temperature and lower water concentration promotes retroaldol reaction instead of dehydration and tautomerism. The reaction at 450℃ in water with a density of 0.1 g/cm3 produced glycol acid with a yield of 89%. We also confirmed glycol aldehyde reacted into glycol acid by Cannizzaro reaction.The reaction rate was estimated as several tens msec, indicating that small reactor is required to enable industrial processes. We showed that the remained research theme are reaction conditions for conversion to glycol acid, reaction of concentrated reactants for industrial process, and utilization of heat from other industry.