The stability of Sn-Beta for the continuous upgrading of hexoses is improved dramatically upon the addition of small amounts of water to the methanol/sugar reaction feed, despite water itself being an unfavorable solvent. Herein, the molecular level origin of this effect is investigated. Spectroscopic studies of the catalytic materials pre-, post- and during operation, with operando UV–vis, ¹¹⁹Sn CPMG MAS NMR, DRIFTS-MS, TGA, TPD/O-MS, and porosimetry, are coupled to additional kinetic studies, to generate detailed structure–activity–lifetime relationships. In doing so, we find that the addition of water influences two particular processes—fouling and active site modification. However, mitigating the second is the most crucial role of water. Indeed, in the absence of water, the loss of Sn–OH and Si–OH sites occurs. Notably, these changes in active site hydration correlate to deactivation and reactivation of the system. The consequences of these findings, both for mechanistic understanding of the system and to the design of alternative regeneration methods, are also discussed.

中文翻译：

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活性位点水合作用控制连续葡萄糖转化过程中Sn-β的稳定性

尽管水本身是不利的溶剂，但向甲醇/糖反应进料中添加少量水后，Sn-Beta连续提纯己糖的稳定性得到了显着改善。在此，研究了这种作用的分子水平起源。催化材料的光谱研究预，后和操作过程中，具有 operando的UV-vis，¹¹⁹Sn CPMG MAS NMR，DRIFTS-MS，TGA，TPD / O-MS和孔隙率法与其他动力学研究相结合，可以生成详细的结构-活性-寿命关系。通过这样做，我们发现添加水会影响两个特定过程-结垢和主动站点修改。但是，缓解第二个问题是水的最关键作用。实际上，在没有水的情况下，会发生Sn-OH和Si-OH位置的损失。值得注意的是，这些活性位点水合的变化与系统的失活和再激活有关。还讨论了这些发现的结果，包括对系统的机械理解以及对替代再生方法的设计。