Selective aqueous phase oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid over Pt/C catalysts: influence of the base and effect of bismuth promotion
Selective aqueous phase oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid over Pt/C catalysts: influence of the base and effect of bismuth promotion
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DOI：
10.1039/c3gc40727f
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发表时间：
2013-01-01
期刊：
影响因子：
9.8
通讯作者：
Besson, Michele
中科院分区：
文献类型：
--
作者：
Rass, Hicham Ait;Essayem, Nadine;Besson, Michele
在活性炭负载的铂和铋铂催化剂存在下，在 100 摄氏度、40 巴空气中、中等碱性水溶液中，将 5-羟甲基糠醛 (HMF) 定量氧化为 2,5-呋喃二甲酸 (FDCA)。 HMF通过5-羟甲基-2-呋喃甲酸(HMFCA)和2,5-二甲酰呋喃(DFF)中间体转化为FDCA；这两种物质都非常具有反应性，并能快速氧化成 5-甲酰呋喃甲酸 (FFCA)，随后的氧化被发现是限速步骤。铂催化剂的制备方法影响金属铂的粒径并修饰载体的表面，从而决定其活性。添加碳酸盐碱（Na2CO3/HMF 摩尔比 = 2）可通过维持氧化反应的适当 pH 值，实现比碳酸氢盐（NaHCO3/HMF = 4）更快的总体转化。异位或原位添加铋促进剂仍能加速反应； Bi/Pt 摩尔比约为 1 时观察到最高活性。 0.2。此外，促进剂有助于防止铂催化剂在回收实验中失活。使用 HMF 与 Pt 的摩尔比为 100 和 Na2CO3 作为均质碱，在不到 2 小时内实现了 HMF (0.1 M) 的定量转化和 FDCA 的产率 >99%。
5-Hydroxymethylfurfural (HMF) was quantitatively oxidized to 2,5-furandicarboxylic acid (FDCA) at 100 degrees C under 40 bar air in moderately basic aqueous solution in the presence of active carbon supported platinum and bismuth-platinum catalysts. The transformation of HMF into FDCA proceeded via the 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) and 2,5-diformylfuran (DFF) intermediates; both of these were very reactive and rapidly oxidized to 5-formylfurancarboxylic acid (FFCA), the subsequent oxidation of which was found to be the rate-limiting step. The preparation method of the platinum catalysts influenced the particle size of metallic platinum and modified the surface of the support, therefore determining the activity. The addition of a carbonate base (Na2CO3/HMF molar ratio = 2) led to faster overall conversion than bicarbonate (NaHCO3/HMF = 4) by maintaining an appropriate pH for the oxidation reaction. The ex situ or in situ addition of a bismuth promoter still accelerated the reaction; the highest activity was observed for a Bi/Pt molar ratio of ca. 0.2. Furthermore, the promoter helped to prevent some deactivation of the Pt catalyst upon recycling experiments. Quantitative conversion of HMF (0.1 M) and >99% yield of FDCA were achieved using a molar ratio of HMF to Pt of 100 and Na2CO3 as the homogeneous base in less than 2 h.