Development of a method for separation of aldoses and ketoses via selective adsorption

如今的化学工业依赖于石脑油资源，尽管基于可再生原料的可持续生产过程正在进行中。石油和生物质衍生化合物在化学成分上的巨大差异反映了它们在极性、挥发性和亲疏水性等物理性质上的巨大差异。因此，传统的产品回收方法，如蒸馏，不适合分离高极性生物质基化合物。因此，由于仍然缺乏有效的产品回收，一些新开发的生物质的利用方法无法扩大。本项目主要研究醛糖和酮糖的分离。醛糖是一种醛基糖，可从生物质中获得。醛糖可以通过生物技术或化学催化过程转化为酮糖。酮糖作为甜味剂、化妆品和药物配方的前体以及平台化学品的底物都有需求。葡萄糖（醛糖）异构化为果糖（酮糖）是这种醛糖-酮糖转化的最突出的例子。酮糖的产率受到热力学限制，这是异构化过程中的一个关键点。因此，从含有平衡醛糖-酮糖混合物的水溶液中回收酮糖是一项重大挑战，因为酮糖不挥发且对温度敏感。本项目旨在开发一种从醛酮溶液中回收酮的有效方法，利用酮在含有苯硼酸部分的聚合物上的选择性吸附。由于酮糖与聚合物的选择性和可逆性结合，分离发生，而醛糖则留在溶液中。酮糖在酸性条件下可从聚合物中解吸。为了优化聚合物结构，将合成具有不同性质的材料，如苯硼基团的性质、硼含量和交联度。这些性质对吸附能力和分离选择性的影响将通过一些模型醛糖-酮糖混合物进行研究：葡萄糖-果糖、乳糖-乳糖、半乳糖-塔格糖等。实验将在批量和连续条件下进行。研究了含硼聚合物在吸附/解吸条件下的长期稳定性。最终，该研究能够优化含硼聚合物的化学组成和吸附/解吸条件，以实现酮糖的高选择性分离。这项研究的结果将为一种潜在的节能和简单的生物精炼厂分离技术提供基础。

Chemical industry depends nowadays on naphtha-resources, though launching sustainable processes based on renewable feedstocks has been in progress. Dramatic differences in the chemical composition of oil- and biomass-derived compounds reflect in considerably different physical properties, such as polarity, volatility, and hydrophilicity/hydrophobicity. As a result, conventional methods for product recovery, such as distillation, are not suitable for isolation of highly-polar biomass-based compounds. Consequently, a number of newly-developed processes on biomass utilization cannot be scaled up, since efficient product recoveries are still missing.This project focuses on separation of aldoses and ketoses. Aldoses, saccharides with an aldehyde group, are highly available from biomass. Aldoses can be converted into ketoses using biotechnological or chemo-catalytic processes. The ketoses are in demand as sweeteners, precursors for cosmetic and pharmaceutical formulations, as well as substrates for platform chemicals. Isomerization of glucose (aldose) into fructose (ketose) is the most prominent example of such aldose-ketose transformations. The yield of a ketose is thermodynamically limited, which presents a key point of isomerization processes. Therefore recovery of a ketose from aqueous solution containing an equilibrium aldose-ketose mixture poses a major challenge, because ketoses are non-volatile and temperature-sensitive.This project aims at developing an efficient method for recovery of ketoses from aqueous solution of aldoses-ketoses using a selective adsorption of ketoses on polymers, containing phenylboronic acid moieties. The separation takes place owing to selective and reversible binding of ketoses to the polymers, whereas aldoses remain in the solution. Ketoses can be desorbed from the polymers under acidic conditions. In order to optimize the polymer structure, materials with different properties, such as nature of phenylboronic moiety, boron content, and crosslinking degree, will be synthesized. The influence of these properties on sorption capacity and selectivity of the separation will be investigated using a number of model aldose-ketose mixtures: glucose-fructose, lactose-lactulose, galactose-tagatose, etc. The experiments will be conducted under batch as well as continuous conditions. The long-term stability of the boron-containing polymers under sorption/desorption conditions will be studied. Ultimately the investigation enables optimizing the chemical composition of boron-containing polymers and sorption/desorption conditions in order to achieve a highly-selective separation of ketoses. The results of the study should present a basis for a potentially energy-efficient and simple separation technique for biorefineries.