One-pot synthesis of 5-hydroxymethylfurfural from carbohydrates using an inexpensive FePO4 catalyst
One-pot synthesis of 5-hydroxymethylfurfural from carbohydrates using an inexpensive FePO4 catalyst
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DOI：
10.1039/c4ra16145a
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发表时间：
2015-02
期刊：
影响因子：
3.9
通讯作者：
Li Yang;Xiaopei Yan;Si-quan Xu;Hao Chen;Haian Xia;Songlin Zuo
中科院分区：
文献类型：
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作者：
Li Yang;Xiaopei Yan;Si-quan Xu;Hao Chen;Haian Xia;Songlin Zuo
碳水化合物催化转化为5-羟甲基糠醛（5-HMF）为获得可再生生物质燃料和化学品提供了一种途径。在这里，我们使用了一种廉价的FePO4催化剂，它在低温下不溶，但在高温下可以部分溶解并作为均相催化剂，在单容器双相反应器中从碳水化合物如果糖、葡萄糖、蔗糖、纤维素和油茶壳（一种木质纤维素原料）中生成5-HMF，而无需添加均相酸。考察了反应温度、反应时间、原料类型和催化剂用量等不同反应条件对果糖转化率和5-羟甲基糠醛收率的影响。采用这种“一锅”双相水/四氢呋喃（THF）反应器系统，在140°C下反应15分钟，从果糖原料中得到最高的5-HMF产率（71.5 mol%）。更有趣的是，在高温下，FePO4催化剂对纤维素和油茶壳的转化也非常活跃，而纤维素和油茶壳在没有添加无机酸的情况下很难转化为5-HMF。以微晶纤维素为原料，采用双相反应体系，5-羟甲基糠醛的产率可达48 mol%。此外，FePO4催化剂在低温下不溶，冷却至室温后可通过沉淀从水溶液中分离和回收。并提出了这些碳水化合物在FePO4催化下可能的脱水反应机理。
Catalytic conversion of carbohydrates to 5-hydroxymethylfurfural (5-HMF) provides a way toward obtaining renewable biomass-based fuels and chemicals. Herein, we use an inexpensive FePO4 catalyst, which is insoluble at low temperature but can be partially dissolved and act as a homogeneous catalyst at high temperature, in a one-vessel biphasic reactor to generate 5-HMF from carbohydrates such as fructose, glucose, sucrose, cellulose, and Camellia oleifera shell (a lignocellulosic feedstock) without the addition of homogeneous acids. The effects of various reaction conditions including reaction temperature, reaction time, feedstock types and the amount of catalyst on fructose conversion and 5-HMF yield were investigated. The highest 5-HMF yield (71.5 mol%) starting from fructose feedstock was achieved using this “one-pot” biphasic water/tetrahydrofuran (THF) reactor system at 140 °C for 15 min. More interestingly, at high temperature, the FePO4 catalyst was also highly active in the conversion of cellulose and Camellia oleifera shell, which are very difficult to convert to 5-HMF without the addition of mineral acids. A high 5-HMF yield of 48 mol% starting from microcrystalline cellulose was also obtained using the biphasic reaction system. Moreover, the FePO4 catalyst could be easily separated and recycled from the aqueous solution via precipitation after cooling to room temperature since it is insoluble at low temperature. Possible dehydration reaction mechanisms of these carbohydrates catalyzed by FePO4 were also proposed.