Conversion of 1-hexanol to di-n-hexyl ether on acidic catalysts

Conversion, selectivity and yield of 1-hexanol liquid phase dehydration to di-n-hexyl ether (DNHE) were determined at 150–190 °C on three acidic catalysts, the thermally stable resin Amberlyst 70, the perfluoroalkanesulfonic Nafion NR50 and the zeolite H-BEA-25, in a batch reactor. The highest conversion and yield were achieved on Amberlyst 70 at 190 °C, but the most selective catalyst was Nafion NR50. Good results were obtained at 190 °C on the zeolite. Apparent activation energies for the three catalysts were in the range 108–140 kJ/mol. Unlike H-BEA-25, the reaction of DNHE synthesis on Amberlyst 70 and NR50 was a bit more active but less selective than the analogous 1-pentanol dehydration to di-n-pentyl ether (DNPE).

The reaction of dehydration of hexanol to di-n-hexyl ether (DNHE) has been studied on Amberlyst 70 (a thermally stable ion-exchange resin), NR50 (a Nafion catalyst) and the zeolite H-BEA-25 at 150–190 °C. The resin Amberlyst 70 gives the highest conversion and yield, but NR50 was a little more selective. Besides DNHE, hexanes, and branched ethers were detected as by-products. The attached graph shows hexanol conversion (XHexanol) and selectivity to DNHE (SDNHE), branched ethers (Sethers) and C6 olefins (Salkenes) at 190 °C over 1 g Amberlyst 70. As seen a selectivity of about 88% is obtained, quite attractive to a potential industrial process of obtaining the ether.Figure optionsDownload high-quality image (66 K)Download as PowerPoint slide