多孔层柱磷酸锆在Prins缩合反应中的应用

制备了一系列不同离子交换的多孔氧化硅层柱磷酸锆, 利用N₂吸附-脱附、 扫描电子显微镜和吡啶吸附红外光谱等方法对材料的结构和酸性进行了表征, 并应用于β-蒎烯与多聚甲醛的Prins缩合反应合成诺卜醇. 结果发现, 层柱磷酸锆对此反应具有优异的催化性能, 锌离子的引入可进一步提高诺卜醇的选择性, 从而得到更高的诺卜醇产率, 于80℃反应4 h后β-蒎烯的转化率为91%, 诺卜醇产率达到83%. 酸性表征结果表明, 诺卜醇产率与催化剂表面Lewis酸(L酸)性位的数目以及L酸位/B酸位的比值密切相关. 该催化剂还具有较好的重复利用性能, 反应5次后产率仅下降12%. 催化剂的失活可能是由于酸性位被积碳覆盖所致.

Porous Phosphate Heterostructure Materials as Green Catalysts in Prins Condensation

Various ion-exchanged porous phosphate heterostructure(PPH) materials were prepared and characterized by SEM, N₂ adsorption and infrared spectra of pyridine adsorption(Py-IR). Their catalytic behavior for the Prins condensation of β-pinene with paraformaldehyde was investigated. All catalysts exhibit good activities and selectivities towards nopol. Zn-ZrP is a more selective one in comparison to others, due to abundant Lewis acid sites and less Brnsted acid sites on the surface. The conversion of β-pinene and the yield of nopol on the catalyst reach 91% and 83% at 80℃. The catalyst is stable and reusable, and the product yield is only reduced by 12% after five runs. The reduction in activity is probably caused by deposition of coke on the active sites and partial collapse of porous structure.