Influence of resin structure on the addition of ethanol to isobutene in the vapour phase

The addition of ethanol to isobutene in the vapour phase has been studied on four commercial macroporous resins. The acid group content of the resins used was about 5 meq g−1, and their degrees of crosslinking were 12, 16, 18 and 20%. Differential conversions were measured for ethanol-isobutene-nitrogen feeds at 53–78.5°C and atmospheric pressure, far from limitation by chemical equilibrium. The rate data showed that isobutene has an enhancing effect on the reaction, whereas ethanol has a strong inhibitory effect in the range studied. The four catalysts showed similar behaviour. At the lower temperatures explored all the resins have similar catalytic activity, but at the highest temperature the resin with 18% divinylbenzene showed the highest activity. This maximum activity can be explained by a greater accessibility to the acid groups, which is in agreement with the literature.