The reactions of methyloxirane were studied in a pulse microreactor over Nation-H, K10 montmorillonite, Mg-Al L(ayered) D(ouble) H(ydroxide) and NaN3-loaded SiMCM-41, to cover a wide acid-base range. The first two solid substances that are acidic, produced appreciable conversion at 363 K, while the latter two that are basic, were hardly active at this temperature. At higher temperature (393 K), however, they displayed fair activity. The nearly superacidic Nafion-H was the most active and transformed the reactant in various ways: single ring opening producing exclusively propionaldehyde, cyclic dimerisation giving five- and six-membered ring compounds, di- and trimerisation producing linear oligomers all occurred. Over the less acidic K10 montmorillonite neither cyclic nor linear oligomer was observed. The NaN3-loaded SiMCM-41 preferred cyclic dimerisation to single ring opening, while the behaviour of the Mg-Al LDH was the opposite. (C) 2003 Elsevier B.V. All rights reserved.