Three-step cascade over a single catalyst: synthesis of 5-(ethoxymethyl)furfural from glucose over a hierarchical lamellar multi-functional zeolite catalyst
Three-step cascade over a single catalyst: synthesis of 5-(ethoxymethyl)furfural from glucose over a hierarchical lamellar multi-functional zeolite catalyst
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DOI：
10.1039/c8ta01242c
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发表时间：
2018-05-07
影响因子：
11.9
通讯作者：
Liu, Dongxia
中科院分区：
文献类型：
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作者：
Bai, Yuanyuan;Wei, Lu;Liu, Dongxia
具有可控介孔/微孔形态和酸性的分级层状沸石的合成是一个广泛应用的研究兴趣的扩展领域。在这里，我们报道了一步合成分级介孔/微孔层状MFI-Sn/Al沸石（即，含有刘易斯酸性Sn-和Al-位点以及布朗斯台德酸性Al-O（H）-Si位点）及其用于将葡萄糖转化为5-（乙氧基甲基）糠醛（EMF）的催化应用。在双季铵盐的辅助下制备了MFI-Sn/Al分子筛（[C22 H45-N+（CH 3）（2）-C6 H12-N+（CH 3）（2）-C6 H13] Br 2-，C22-6-6）模板，组成为100 SiO（2）/5C（22-6-6）/18.5Na（2）O/xAl（2）O（3）/ySnO（2）/2957 H（2）O（x = 0.5、1和2; y = 1和2）。MFI-Sn/Al沸石具有双重介孔/微孔性和双重刘易斯和布朗斯台德酸性，这使得在乙醇溶剂中从葡萄糖合成EMF的三步反应级联成为可能。该反应通过葡萄糖在刘易斯酸性Sn位上异构化为果糖，果糖脱水为5-羟甲基糠醛（HMF），然后HMF和乙醇在Bronsted酸性Al-O（H）-Si位上醚化为EMF。在单一沸石催化剂中多种酸性的共存使得用于碳水化合物改质的一锅级联反应成为可能。在MFI-Sn/Al沸石中的双重介孔/微孔有利于在处理庞大的生物质分子中的传质。这两种类型的酸度和介孔/微孔的平衡实现了EMF产率高达44%的葡萄糖反应物。
The synthesis of hierarchical lamellar zeolites with a controlled meso-/microporous morphology and acidity is an expanding area of research interest for a wide range of applications. Here, we report a onestep synthesis of a hierarchical meso-/microporous lamellar MFI-Sn/Al zeolite (i.e., containing both Lewis acidic Sn- and Al-sites and a Bronsted acidic Al-O(H)-Si site) and its catalytic application for the conversion of glucose into 5-(ethoxymethyl) furfural (EMF). The MFI-Sn/Al zeolite was prepared with the assistance of a diquaternary ammonium ([C22H45-N+(CH3)(2)-C6H12-N+(CH3)(2)-C6H13]Br2-, C22-6-6) template in a composition of 100SiO(2)/5C(22-6-6)/18.5Na(2)O/xAl(2)O(3)/ySnO(2)/2957H(2)O (x = 0.5, 1, and 2; y = 1 and 2, respectively). The MFI-Sn/Al zeolites innovatively feature dual meso-/microporosity and dual Lewis and Bronsted acidity, which enabled a three-step reaction cascade for EMF synthesis from glucose in ethanol solvent. The reaction proceeded via the isomerization of glucose to fructose over Lewis acidic Sn sites and the dehydration of fructose to 5-hydroxymethylfurfural (HMF) and then the etherification of HMF and ethanol to EMF over the Bronsted acidic Al-O(H)-Si sites. The co-existence of multiple acidities in a single zeolite catalyst enabled one-pot cascade reactions for carbohydrate upgrading. The dual meso-/microporosity in the MFI-Sn/Al zeolites facilitated mass transport in processing of bulky biomass molecules. The balance of both types of acidity and meso-/microporosity realized an EMF yield as high as 44% from the glucose reactant.