Effective direct esterification of butanol by eco-friendly Preyssler catalyst, [NaP5W30O110]14−

Direct esterification of butanol to butylbutanoate in the absence of butanoic acid has been investigated by a series of green solid acid catalysts, including H14[NaP5W30O110], H14-P5, H14[NaP5W29MoO110], H14-P5Mo and silica supported H14[NaP5W30O110], H14-P5/SiO2, with H2O2 as oxidizing agent at reflux and at room temperatures. The performance of these eco-friendly catalysts were compared with H2SO4. Maximum butylbutanoate yield and product selectivity (100%) was observed by using H14-P5Mo as the catalyst. The effects of various parameters such as catalyst type, reaction times, reaction temperatures, and molar ratio of n-butanol to hydrogen peroxide have been studied. The green catalysts can be easily recovered and recycled with retention of their initial structure and activity.

Graphical abstractCatalytic activity of recyclable Preyssler acid, H14-P5 and its different forms such as H14-P5Mo and H14-P5/SiO2 have been investigated, in liquid phase in the presence of hydrogen peroxide. A systematic study has been made to find the effect of catalyst type, the molar ratio of alcohol to hydrogen peroxide, temperature and the duration of reaction on the synthesis of the ester. All the catalysts have been found to be active and exhibit 100% selectivity and recyclable. Figure optionsDownload full-size imageDownload as PowerPoint slide