Thermal reactions of alkali 4-(bromomethyl)benzoate–bromoacetate binary systems in the bulk

Abstract

Thermal reactions of alkali 4-(bromomethyl)benzoate–bromoacetate (4-BMBA–BA) binary systems in the bulk have been investigated. Those of equimolar sodium and potassium 4-BMBA–BA result in copolycondensation in the solid state to give a copolyester. However, reaction of the equimolar lithium salts at 210 °C for 1 h, followed by esterification, afford methyl 4-(bromomethyl)benzoyloxyacetate as a cross-condensed dimer in 30% yield. The yield increases in the initial hour, but then gradually decreases due to the formation of oligomers. The X-ray diffraction pattern of the Li salts (powder method) indicates a new crystal phase, which is different from the individual patterns of lithium bromoacetate and lithium 4-(bromomethyl)benzoate. The formation of the new crystal phase contributes to a reduced melting point, and the Li salts react in the liquid phase without pyrolysis, causing cross-condensed dimerization.