The properties and catalytic activity of zeolite MWW were investigated before and after water treatment at 160 °C for 48 h to evaluate its possible behavior and usefulness in biomass conversion. Four different forms of the MWW zeolite were studied along with a sample of commercial zeolite beta for comparison: MCM-22, MCM-49, MCM-56 and Ce/MCM-22. The treated MWW zeolites showed lesser impact of the exposure to water than the tested zeolite beta. X-ray powder diffraction indicated negligible structural degradation. ²⁷Al NMR and FTIR showed reduction of the acid site concentration, while micropore volume decreased by up to 50% as determined by nitrogen sorption. All MWW samples showed high catalytic activity in the reaction of n-propanol with 3,4-dihydro-2H-pyran (DHP). Similar reactions between tert-butanol and DHP also showed better activity and relatively small effect of the water treatment for the MWW materials with the exception of the Ce/MCM-22. The latter and the reference zeolite beta showed about 3 times lower conversion. Ce/MCM-22 was the only sample showing no decrease in acid site concentration as the result of aging in hot water so its lower activity was surprising. We propose that larger size of Ce may be responsible for blocking or otherwise affecting accessibility of the active sites. The study shows that MWW zeolites may show higher activity than zeolite beta. Incorporation of Ce improves stability of acid centers and although overall performance diminishes it leaves room for improvement, possibly by expanding the interlayer structure.

在160°C水处理48 h之前和之后，对MWW沸石的性质和催化活性进行了研究，以评估其可能的行为和在生物质转化中的有用性。研究了四种不同形式的MWW沸石以及用于比较的商用沸石β样品：MCM-22，MCM-49，MCM-56和Ce / MCM-22。处理过的MWW沸石暴露于水中的影响比测试过的β沸石要小。X射线粉末衍射表明可忽略的结构降解。²⁷ Al NMR和FTIR显示酸位点浓度降低，而微孔体积最多减少50％（通过氮吸附测定）。所有的MWW样品在n的反应中均显示出高催化活性-丙醇与3,4-二氢-2H-吡喃（DHP）。叔之间的类似反应除Ce / MCM-22以外，对于MWW材料，-丁醇和DHP的活性也更高，而水处理的效果也相对较小。后者和参考沸石β的转化率降低了约3倍。Ce / MCM-22是唯一在热水中不会因老化而显示酸性位点浓度降低的样品，因此其较低的活性令人惊讶。我们建议较大尺寸的Ce可能是阻止或以其他方式影响活动站点的可访问性的原因。研究表明，MWW沸石的活性可能高于β沸石。铈的掺入改善了酸中心的稳定性，尽管整体性能降低了，但仍可能通过扩大中间层结构而留有改进的余地。