Solid Catalysts For N-butanalaldol Condensation And For One-pot Sequentialaldol Condensation-hydrogenation To 2-ethylhexanol

2-Ethylhexanol（2EHO）, an important basic organic chemical, is mainly used to produce plasticizers. The industrial manufacture of 2EHO usually adopts the low-pressure carbonylation of propylene and syngas, which comprises three steps: carbonylation of propylene and syngas to n-butanal, n-butanal self-condensation to 2-ehtylhexenal（2E2H）and 2E2 H hydrogenation to 2EHO. In the present work, the solid acid catalyst used for n-butanal self-condensation to 2E2 H and the metal-solid acid bi-functional catalyst used for one-pot sequential aldol condensation-hydrogenation of n-butanal to 2EHO were studied.First of all, La-modified γ-Al₂O₃ catalyst（La-Al₂O₃） was prepared on the basis of our previous work and the catalytic performance for n-butanal self-condensation reaction was studied. The catalytic performance of the La-Al₂O₃ catalysts prepared by two different methods was compared and the results showed that the La-Al₂O₃ catalyst prepared by colloidal chemical method was better. The suitable preparation conditions of the La-Al₂O₃ catalyst were obtained as follows: La2O3 loading=7.5%, calcined at 700 ℃ for 4h. The suitable reaction conditions for n-butanal self-condensation reaction were obtained as follows: m（catalyst）:m（n-butanal）=0.15:1, reaction temperature of 180℃, and reaction time of 8h. Under the above conditions, the conversation of n-butanal was 90.6% and the selectivity of 2E2 H was 91.7%. And then the reusability test results showed that the La-Al₂O₃ could be reused four times without a significant loss in its catalytic performance.In addition, the by-products existing in the reaction system were identified by GC-MS analysis and then a possible reaction network of n-butanal self-condensation to 2E2 H catalyzed by the La-Al₂O₃ was established.Secondly, a metal-solid acid bi-functional catalyst Ni/La-Al₂O₃ was prepared for one-pot sequential aldol condensation-hydrogenation of n-butanal. The effects of preparation process parameters on catalytic performance of Ni/La-Al₂O₃ and reaction conditions of hydrogenation process were investigated. The suitable preparation conditions for Ni/La-Al₂O₃ were obtained as follows: Ni loading=25%, calcined at 500 ℃ for 4h,reduced at 550℃ for 3h under a H2（20 vol.% in N2） atmosphere. The suitable reaction conditions were obtained as follows: m（catalyst）:m（n-butanal）=0.15:1, reaction at 180℃for8h, then reaction at 180 ℃ for 6h under 4MPa H2. Under the suitable conditions, theconversation of n-butanal was 100% and the yield of 2EHO was 67.0%. In addition, the components existing in the reaction system of the one-pot sequential aldol condensation-hydrogenation of n-butanal to 2EHO were indentified by GC-MS and a possible reaction network was established. The analyses of XRD and SEM showed that the deactivation of Ni/La-Al₂O₃ was caused by γ-Al₂O₃ hydration. Some attempts were made for inhibiting the hydration of γ-Al₂O₃ by introducing some hydrophobic groups on the surface of γ-Al₂O₃.