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The aldol condensations of various aldehydes with ketones in the presence of anionic (basic) ion‐exchange resins have been investigated. Both batch and continuous modes were studied and compared for the reaction of citral (a mixture of geranial and neral) with acetone to give ψ‐ionone. Different reaction conditions were investigated, and the performances of five different ion‐exchange resins were compared. The most stable resins could be used for 10 cycles in batch mode or 1000 min in continuous mode without a significant loss in activity or selectivity.

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The Cover shows a cross aldol condensation over an ion‐exchange resin to form pseuodionone, which has a scent similar to that of violets. In their Full Paper, W. Bonrath et al. demonstrate condensations of various aldehydes with ketones in the presence of anionic (basic) ion‐exchange resins. The reactions were run in batch and continuous modes. Over 10 runs, no significant loss in activity and selectivity was observed for two of the tested resins. In continuous mode, a stable performance was noted for more than 15 h. More information can be found in the Full Paper by W. Bonrath et al. on page 3584 in Issue 23, 2016 (DOI: 10.1002/cctc.201600867).