Liquid phase aldol condensation of cyclopentanone with valeraldehyde catalysed by oxynitrides possessing tuneable acid–base properties

The aldol condensation reaction between valeraldehyde and cyclopentanone was carried out in a batch reactor, at atmospheric pressure and 130 °C over “AlPON” and “ZrPON” catalysts. Those catalysts were obtained by heating AlPO4 and Zr0.9PO4.3 phosphates in a flow of gaseous ammonia at 750 and 700 °C, respectively. The nitridation treatment allows to substitute framework oxygen atoms by nitrogen atoms, consequently reducing the number of solid acid sites and increasing the number of basic sites. Nitridation has a positive effect on valeraldehyde conversion which increases from 33 to 57% after 2 h of reaction for the “AlPO” system and from 80 to 94% after 2 h for the “ZrPO” system. The influence of the acid–base properties of catalysts for this particular reaction is discussed by measuring the activity and selectivity of basic (MgO), and amphoteric (Al2O3) catalysts. The zirconophosphate precursor “ZrPO” and its nitrided samples are the most active for the reaction.

The aldol condensation reaction between cyclopentanone and pentanal was carried out in a batch reactor, at atmospheric pressure and 130 °C over phosphate precursors AlPO4 and Zr0.9PO4.3 and their nitrided samples “AlPON” and “ZrPON”. The effect of nitridation on the catalytic activity is discussed in relation with the influence of nitridation on the acidity/basicity. Figure optionsDownload as PowerPoint slide