Ion exchange resins as catalysts for the liquid-phase dehydration of 1-butanol to di-n-butyl ether

• Activity increases with high acid capacity and medium polymer chain concentration.
• Selectivity to dibutyl ether is higher in resins with a more flexible structure.
• The presence of isobutanol in the reagent enhances branched ether formation.
• The presence of ethanol leads to ethyl-butyl ether and diethyl ether formation.

This work reports the production of di-n-butyl ether (DNBE) by means of 1-butanol dehydration in the liquid phase on acidic ion-exchange resins. Dehydration experiments were performed at 150 °C and 40 bar on 13 styrene-codivinylbenzene ion exchangers of different morphology. By comparing 1-butanol conversions to DNBE and initial reaction rates it is concluded that oversulfonated resins are the most active catalysts for 1-butanol dehydration reaction whereas gel-type resins that swell significantly in the reaction medium as well as the macroreticular thermostable resin Amberlyst 70 are the most selective to DNBE. The highest DNBE yield was achieved on Amberlyst 36. The influence of typical 1-butanol impurities on the dehydration reaction were also investigated showing that the presence of 2-methyl-1-propanol (isobutanol) enhances the formation of branched ethers such as 1-(1-methylpropoxy) butane and 1-(2-methylpropoxy) butane, whereas the presence of ethanol and acetone yields ethyl butyl ether and, to a much lesser extent, diethyl ether.

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