Studies of the Organic Reactions of Metal Carbonyl. II. The Reaction of Olefin Oxide with Cobalt Hydrocarbonyl

Abstract

Abstract The reactions of olefin oxides with cobalt hydrocarbonyl have been studied. The effect of the reaction conditions on the nature of the reaction, especially that of propylene oxide, has been examined in detail. Propylene oxide gave only the products with β-hydroxy-n-butyryl structure under these reaction conditions: temperature, 25∼45°C; atmosphere; nitrogen or carbon monoxide; and mole ratio of propylene oxide, 1.4∼6.2. The inhibitory effect of a nitrogen atmosphere on the formation of carbonylated products (ester and aldehyde) has been observed ; under nitrogen, some side reaction was highly promoted, and the formation of carbonylated products was thereby prevented. The reactions of ethylene oxide, cyclohexene oxide, styrene oxide and epichlorohydrin have also been studied. In the reactions of styrene oxide, the mole ratio of styrene oxide had a significant effect on the nature of the reaction; at a relatively small mole ratio, the reduction gave, mainly two isomeric alcohols, but as the mole ratio increased, the carboxylation reaction seemed to increase. Epichlorohydrin gave a product with a γ-chloro-β-hydroxy-n-butyryl structure, which corresponds to that which propylene oxide gave. The order of the reactivity of these olefin oxides is as follows: cyclohexene oxide (about 5) and styrene oxide>propylene oxide (1)>ethylene oxide>>epichlorohydrin (1⁄20∼40) ; (the numbers indicate the relative reactivities). This fact seems to indicate that, in general, internal (and conjugated) olefin oxides are more reactive than terminal olefin oxides. By analogy with the relative reactivity of propylene oxide and epichlorohydrin with cobalt hydrocarbonyl, perchloric acid and ammonia, it may reasonably be considered that cobalt hydrocarbonyl reacts as an acid. Pentene-1 appeared to be less reactive than propylene oxide.