Among the different metal-promoted catalysts for the conversion of C6 sugars to platform chemicals, Sn-based catalysts have demonstrated high activity for different types of reactions, such as isomerization, retro-aldol conversion and dehydration of glucose or its isomers. The form of Sn species, as oxides or ions, along with the properties of the support are important factors determining the prevalent reaction pathway and product distribution. In this framework, we have studied the conversion of glucose mainly in biphasic (H₂O/DMSO) media, using four types of Sn-based catalysts, i.e. Sn(II) and Sn(IV) as homogeneous catalysts (Cl- salts) or as the respective oxides in heterogeneous systems, Sn(IV) as SnO₂ supported on γ-Al₂O₃, zeolites (ZSM-5 and Beta) or mesoporous aluminosilicates (Al-MCM-41), and Sn^δ+ as ion-exchange cations on the above zeolites. The solid catalysts were characterized by XRD, FT-IR/pyridine, ICP-OES, XRF and N₂ porosimetry. Under the studied conditions, the main products obtained were 5-HMF and lactic acid in both the homogeneous and heterogeneous systems. Based on the results obtained, it was concluded that the Lewis acidity offered by Sn oxides promotes the retro-aldol reaction pathway towards lactic acid, while the Lewis acidity offered by γ-Al₂O₃ enhances the synthesis of both 5-HMF and lactic acid. By combining these two functions, the Sn impregnated γ-Al₂O₃ catalysts induce further increase of both 5-HMF and lactic acid yields. In case of catalysts that possess Brønsted acidity as well (i.e. Sn ion-exchanged or impregnated zeolites and Al-MCM-41), dehydration reactions are promoted and the product selectivity is shifted towards 5-HMF synthesis. The highest 5-HMF molar yield of 27.5% (at complete glucose conversion) was achieved by Sn20/γ-Al₂O₃ accompanied by lactic acid at 16.5% molar yield. For this catalyst the effect of the solvent, catalyst concentration and reaction temperature and time, were further evaluated.

在用于C6糖转化为平台化学品的不同金属促进的催化剂中，锡基催化剂已表现出对不同类型反应的高活性，例如异构化，逆醛醇转化和葡萄糖或其异构体的脱水。Sn形式的氧化物或离子形式以及载体的性质是决定普遍反应途径和产物分布的重要因素。在此框架下，我们研究了使用四种类型的Sn基催化剂，即Sn（II）和Sn（IV）作为均相催化剂（Cl盐），主要在双相（H ₂ O / DMSO）介质中转化葡萄糖的方法。或作为异构系统的各自的氧化物，锡（IV）以SnO ₂支撑在γ-Al系₂ ö ₃，沸石（ZSM-5和Beta）或中孔铝硅酸盐（Al-MCM-41）和Snδ ⁺作为上述沸石上的离子交换阳离子。通过XRD，FT-IR /吡啶，ICP-OES，XRF和N ₂孔隙率法对固体催化剂进行了表征。在研究条件下，均相和非均相体系中获得的主要产物为5-HMF和乳酸。基于获得的结果，可以得出结论，通过Sn的氧化物提供的路易斯酸性促进向乳酸的复古醛醇缩合反应途径，而路易斯酸性所提供的γ-Al _2个ö ₃增强5-HMF和乳酸的合成酸。通过组合这两个功能，Sn的浸渍的γ-Al ₂ ö ₃催化剂引起5-HMF和乳酸产率的进一步增加。在同样具有布朗斯台德酸度的催化剂的情况下（即锡离子交换或浸渍的沸石和Al-MCM-41），促进了脱水反应，并且产物选择性转向了5-HMF合成。的27.5％的最高5-HMF摩尔产率（在完整的葡萄糖转化）由SN20 /γ-Al系实现₂ ö ₃伴有乳酸16.5％摩尔产率。对于该催化剂，进一步评估了溶剂，催化剂浓度以及反应温度和时间的影响。