A series of materials based on the immobilization of the 12-tungstophosphoric heteropolyacid over zirconia supports have been prepared and applied as heterogeneous acid catalysts in the esterification of palmitic acid with methanol as a model reaction for the preliminary stage of the biodiesel production. The title materials have been obtained through the sol-gel method combined with a subsequent hydrothermal treatment at mild conditions, which affords catalysts with larger porosity and higher thermal and chemical stability under the esterification reaction conditions than other preparative approaches. Generating the zirconia support by hydrolysis of an alkoxyde precursor in the presence of the heteropolyacid leads to materials with homogeneously well-dispersed clusters, as well as to an increasing contribution of the tetragonal ZrO₂ crystalline phase, a decreasing size of the nanoparticles and larger microporous volumes as the loading of the Keggin-type species increases. The 12-tungstophosphoric acid retains its catalytic activity in the esterification of palmitic acid with methanol at 60 °C upon immobilization over zirconia and conversions even higher than those observed under homogeneous conditions are obtained due to the active contribution of the support. The sample with a 30% mass percentage of heteropolyacid has been identified as the most efficient catalyst because it affords conversions above the 90% and shows the lower loss of activity over successive reaction runs among all of our materials. This loss of activity has been analyzed on the basis of the leaching of the catalyst and the fouling of the materials.

制备了一系列基于12-钨磷酸杂多酸固定在氧化锆载体上的材料，并将其作为异质酸催化剂用于棕榈酸与甲醇的酯化反应，作为生物柴油生产初期阶段的模型反应。通过溶胶-凝胶法结合随后在温和条件下的水热处理获得了标题材料，与其他制备方法相比，该酯化催化剂在酯化反应条件下具有更大的孔隙率以及更高的热稳定性和化学稳定性。在杂多酸的存在下，通过烷氧基前体的水解生成氧化锆载体，会导致材料具有均匀分散的簇，并增加了四方ZrO的贡献。₂晶相，随着Keggin型物质的负载增加，纳米粒子的尺寸减小，微孔体积增大。十二氧化钨磷酸在固定在氧化锆上时，在60°C的棕榈酸与甲醇的酯化反应中保留了其催化活性，由于载体的积极贡献，其转化率甚至高于在均相条件下观察到的转化率。质量百分比为30％的杂多酸样品被认为是最有效的催化剂，因为它提供的转化率超过90％，并且在我们所有材料中，相继反应运行均显示出较低的活性损失。已经基于催化剂的浸出和材料的结垢分析了这种活性损失。