Transformation of 1-butene over AlSBA-15 synthesized at different conditions of pH and hydrolysis

In the present work a detailed study of the effect of pH, in the range of 0–4.5, over the mesostructure of SBA-15 and catalytic transformation of 1-butene has been carried out. Also, the effect of silica source hydrolysis on the Al incorporation at different pH was studied varying the order of addition of an aluminium salt, before and after hydrolysis. The samples were characterized by SEM, TEM, ICP and N2 adsorption. The materials showed a highly ordered hexagonal mesostructure for all the pH range studied. A decrease in particle size with increase of pH was observed. Al incorporation was favoured as pH increased; the highest incorporation was obtained at pH 4.5. An important effect of hydrolysis on Al incorporation was observed depending of metal incorporation. Hydrolysis had also an effect on the distribution and strength of the acid sites. The materials with the highest skeletal isomerization selectivity were those synthesized at pH 4.5.

The catalytic transformation of 1-butene has been carried over AlSBA-15 catalysts synthesized by adding an aluminium salt, before (BH) or after (AH) silica source hydrolysis at pH 0–4.5. Hydrolysis affected the distribution and strength of the acid sites. The highest 1-butene skeletal isomerization efficiency (SIE) and Al incorporation was obtained over catalysts synthesized at pH 4.5.Figure optionsDownload high-quality image (79 K)Download as PowerPoint slide