EFFECT OF PRESSURE ON THE FREE RADICAL REACTIONS OF 2-ALKOXYTETRAHYDROPYRANS

Article abstract of DOI:10.1007/BF01150883

In free radical transformations of 2-methoxy- and 2-ethoxytetrahydropyran initiated by tert-butoxy radicals at 130 deg C, the relative rate of formation of δ-valerolactone and valeric acid ester was found to change periodically with increase in the extent of transformation, expressed as tert-butyl alcohol (TBA) concentration.The ratio of lactone: ether concentration is determined not by the pressure (up to 1000 MPa) as suggested earlier, but by the amplitudes and phase displacement of the oscillations of the rates of formation of lactone and ester.These results are explained by changes in the physical structure of the solution in proportion to the buildup of reaction products as a result of which the reactivity of the 2-alkoxytetrahydropyranyl radical changes in respect of rupture of the endocyclic and exocyclic C-O bonds. Keywords: pressure, 2-alkoxytetrahydropyran, free-radical reaction, synthesis of δ-valerolactone.