This work deals with the liquid-phase hydrogenation of citral over Pt monometallic and PtSn bimetallic catalysts supported on commercial silica. Bimetallic catalysts contain different Sn/Pt molar ratio of 0.5, 1.0 and 1.5. Cyclohexane or 2-propanol were used as solvent. The catalysts were characterized by N₂-physisorption, XRD, NH₃-TPD, H₂-chemisorption, and TPR. Both XRD and TPR results showed the formation of PtSn and Pt₃Sn. The proportion of Pt–Sn alloys was related to the Sn/Pt molar ratio: the greater the Sn/Pt molar ratio, the greater the amount of PtSn alloy species. The amount of these species was related to the catalytic activity and selectivity in the hydrogenation of citral. Pt monometallic catalysts showed a high initial catalytic activity with high selectivity to citronellal. Bimetallic catalysts exhibited high activity and selectivity to unsaturated alcohols as geraniol and nerol. With cyclohexane as solvent, a greater amount of Pt₃Sn species promote consecutive hydrogenations, and with a greater amount of PtSn alloy the formation of compounds related to cyclization of citronellal was observed. The results showed that using a balanced amount of species (Pt₃Sn and PtSn) and 2-propanol as solvent, a synergic effect that promotes high activity and selectivity to geraniol and nerol was observed maintaining the same levels of selectivity along reaction time.

这项工作涉及在商用二氧化硅上负载的Pt单金属和PtSn双金属催化剂上柠檬醛的液相加氢。双金属催化剂包含0.5、1.0和1.5的不同的Sn / Pt摩尔比。环己烷或2-丙醇用作溶剂。催化剂的特征在于N _2-物理吸附，XRD，NH ₃ -TPD，H _2-化学吸附和TPR。XRD和TPR结果均显示PtSn和Pt ₃的形成锡 Pt-Sn合金的比例与Sn / Pt摩尔比有关：Sn / Pt摩尔比越大，PtSn合金种类的数量就越大。这些物质的量与柠檬醛加氢中的催化活性和选择性有关。铂单金属催化剂显示出高的初始催化活性和对香茅醛的高选择性。双金属催化剂显示出高活性和对不饱和醇如香叶醇和神经醇的选择性。以环己烷为溶剂，大量的Pt ₃ Sn会促进连续氢化，而在大量的PtSn合金中，会观察到与香茅醛环化有关的化合物的形成。结果表明，使用平衡数量的物种（Pt ₃（Sn和PtSn）和2-丙醇作为溶剂，观察到协同效应，可促进高活性和对香叶醇和神经醇的选择性，并沿反应时间保持相同水平的选择性。