Optimization of bifunctional Ni catalysts was performed to enhance the catalytic performance in the one-pot synthesis of commercially valuable menthol from citral. The effect of nickel precursors (nitrate, chloride, acetate, and sulfate) and the addition of bentonite clay was investigated in citral transformations in a batch reactor at 70 °C and 10 bar hydrogen, demonstrating higher activity for the Ni-H-β-38-bentonite composite derived from a nickel nitrate precursor, which can be attributed to a higher surface area, optimal Brønsted to Lewis acidity and metal particle size, as well as the egg-shell distribution of Ni particles. H-β-38 impregnated with nickel nitrate, followed by calcination and reduction, was shaped with bentonite as a binder to give extrudates for exploring the citral transformations in the trickle-bed reactor at 50–70 °C and 10 bar hydrogen. The highest selectivity to the desired menthols of 45% was obtained with 70% stereoselectivity to the menthol isomer at 70 °C. The apparent activation energy for citral transformations to menthols of 18.6 kJ/mol indicated the presence of mass transfer limitations. Catalytic activity was linked with the physical-chemical properties, which were characterized by transmission electron microscopy, X-ray diffraction, temperature-programmed reduction, Fourier transform infrared spectroscopy with pyridine, N₂ physisorption, and inductively coupled plasma–optical emission spectrometry methods.

中文翻译：

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含膨润土黏土粘合剂的Ni/H-β-38挤出物在间歇式和连续式反应器中一锅法从柠檬醛合成薄荷醇

对双功能 Ni 催化剂进行了优化，以提高从柠檬醛一锅法合成具有商业价值的薄荷醇的催化性能。在 70 °C 和 10 巴氢气的间歇式反应器中研究了镍前体（硝酸盐、氯化物、乙酸盐和硫酸盐）和添加膨润土对柠檬醛转化的影响，证明了 Ni-H-β- 的更高活性源自硝酸镍前体的 38-膨润土复合材料，这可归因于更高的表面积、最佳的 Brønsted to Lewis 酸度和金属粒径，以及镍颗粒的蛋壳分布。H-β-38用硝酸镍浸渍，然后煅烧还原，用膨润土作为粘合剂成型，得到挤出物，用于在 50–70 °C 和 10 bar 氢气下探索滴流床反应器中的柠檬醛转化。在 70 °C 下，对所需薄荷醇的最高选择性为 45%，对薄荷醇异构体的立体选择性为 70%。柠檬醛转化为薄荷醇的表观活化能为 18.6 kJ/mol，表明存在传质限制。催化活性与物理化学性质有关，其特征在于透射电子显微镜、X 射线衍射、程序升温还原、傅里叶变换红外光谱与吡啶、N 柠檬醛转化为薄荷醇的表观活化能为 18.6 kJ/mol，表明存在传质限制。催化活性与物理化学性质有关，其特征在于透射电子显微镜、X 射线衍射、程序升温还原、傅里叶变换红外光谱与吡啶、N 柠檬醛转化为薄荷醇的表观活化能为 18.6 kJ/mol，表明存在传质限制。催化活性与物理化学性质有关，其特征在于透射电子显微镜、X 射线衍射、程序升温还原、傅里叶变换红外光谱与吡啶、N₂物理吸附和电感耦合等离子体发射光谱法。