Oxidation of heavy 1-olefins (C12=–C20=) with TBHP using a modified Wacker system

The oxidation of heavy olefins (C12–C20) was carried out using a modified Wacker system with TBHP as oxidant and acetonitrile as solvent at 80 °C. This system allowed the oxidation of 1-octadecene giving rise to 90% conversion with 60% selectivity towards 2-octadecanone after 2 h while the addition of β-cyclodextrins did not increase the production of 2-octadecanone. The oxidation of a equimolar mixture of n-dodecane + 1-dodecene enhanced markedly the selectivity towards 2-dodecanone yielding 63% instead of 34% in the absence of n-paraffin after 2 h, likely due to a dilution effect of the n  -dodecane which reduces the extent of the isomerization reactions. The oxidation of a equimolar mixture C12=+C16=+C20= in the presence of equimolar amounts of their corresponding n-paraffins gave rise to practically complete conversion and selectivities toward 2-methylketones within 70–90% enhancing with decreasing chain length due to their higher solubility in the biphasic system. The activity of the catalyst dropped after two reaction cycles indicating its deactivation by the formation of palladium clusters. However, it was possible to obtain similar results in terms of activity and selectivity by increasing the (1-dodecene)/(PdCl2) ratio to 100, which is expected to increase the catalyst lifetime by decreasing the extent of palladium aggregation. In this regard, the reported system is rather promising for the oxidation of heavy 1-olefins towards methyl ketones.

Graphical abstractThe oxidation of heavy 1-olefins (C12=–C20=) was carried out using a modified Wacker system with TBHP as oxidant and acetonitrile as solvent at 80 °C. The presence of n-paraffins in the mixture increased the selectivity towards 2-methylketone due to a dilution effect which reduces the extent of the isomerisation reactions.Figure optionsDownload full-size imageDownload high-quality image (36 K)Download as PowerPoint slide