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8Ethyl-octyl ether (EOE) liquid phase synthesis from ethanol and 1-octanol over ion-exchange 9resins is feasible at 423K, though di-ethyl ether and di-n-octyl ether were also formed. The 10 influence of the catalyst morphology on the reaction was checked by testing twenty-two acidic 11 resins. Gel-type resins of low crosslinking degree yielded the higher amounts of EOE, whereas 12 macroreticular ones of high crosslinking degree gave mainly di-ethyl ether. Ethanol conversion 13 highly depends on the resin acid capacity, [H + ], whereas 1-octanol conversion and selectivity to 14 EOE depends on the specific volume of swollen polymer, V sp , and porosity. The variation of 15 ethanol and 1-octanol conversion, selectivity to EOE with respect to both alcohols as well as 16 ethers TOF as a function of [H + ]/V sp suggests that a part of the active sites does not take part in 17 the EOE synthesis reaction on highly cross-linked resins. Amberlyst 70 could be interesting in 18 industry due to its selectivity to EOE and higher thermal stability. 19

The equilibrium constants of the liquid-phase dehydration of 1-hexanol to dihexyl ether (DNHE) and water were determined in the temperature range of (423 to 463) K on Amberlyst 70. The equilibrium constants of the two main side reactions, DNHE decomposition to 1-hexene and 1-hexanol and isomerization of 1-hexene to 2-hexene, were also studied. The etherification reaction proved to be slightly exothermic, with an enthalpy change of reaction of -( 9.5 ( 0.2) kJ • mol -1 at 298 K. From this value, the standard formation enthalpy and molar entropy of DNHE were computed to be -(478.6 ( 0.8) kJ • mol -1 and (517.4 ( 0.5) J • K -1 • mol -1 , respectively. A correction concerning the effect of pressure on the entropy proved to be necessary when computing liquid-phase entropy from gas-phase data. The isomerization of 1-hexene to 2-hexene is exothermic, whereas the decomposition of DNHE is endothermic.

The thermodynamic equilibrium of the liquid-phase bimolecular dehydration of 1-pentanol to di-n-pentyl ether (DNPE) and water was studied in the temperature range of 423-463 K over Amberlyst 70. Furthermore, the equilibrium position of two side reactions could be followed, DNPE decomposition to 1-pentanol and 1-pentene and isomerization of 1-pentene to 2-pentene. The etherification reaction proved to be slightly exothermic, with an enthalpy change of reaction at 298.15 K of -(3.8 ( 0.6) kJ mol -1 . From this value, the standard formation enthalpy and molar entropy of DNPE were computed to be -(421.1 ( 1.2) kJ mol -1 and 473.71 J (K‚mol) -1 , respectively. The enthalpy changes of the reaction of DNPE decomposition to 1-pentene and 1-pentanol and 1-pentene isomerization to 2-pentene were 63.4 ( 0.9 and -19.7 ( 2.1 kJ mol -1 , respectively.