Aldol self-condensation of n-butyraldehyde to 2-ethyl-2-hexenal is one of the important processes for industrial production of 2-ethyl hexanol. Firstly

the catalytic performance of H3PW12O40

H4SiW12O40 and H3PMo12O40 was evaluated and the results showed that H4SiW12O40 presented the best catalytic activity. Secondly

supported H4SiW12O40 catalysts were prepared with the impregnation method and the influence of the kind of support and preparation process parameters on catalyst performance was investigated. The suitable preparation conditions were determined as follows: taking SiO2 as support

loading of H4SiW12O40= 50% (mass)

calcination temperature of 150℃ and calcination time of 2 h. The effect of reaction conditions on the catalyst performance of H4SiW12O40/SiO2 was also studied and the suitable reaction conditions was determined as follows: mass ratio of catalyst to n-butyraldehyde 0.15

reaction temperature of 120℃ and reaction time of 6 h. Under the above conditions

the conversion of n-butyraldehyde and the selectivity to 2-ethyl-2-hexenal were 90.4% and 89.2%

respectively. However

the reusability of H4SiW12O40/SiO2 catalyst was poor. Analysis of ICP-AES and XRD demonstrated that the loss of active species H4SiW12O40 was the main reason. In order to decrease the loss of H4SiW12O40

H4SiW12O40/SiO2 catalyst was prepared with the sol-gel method using [emim]BF4 ionic liquid as template. The activity test result showed that the reusability of the prepared catalyst was improved to some extent.