Selective monoetherification and monoesterificatton of diols and diacids under phase-transfer conditions

Research on the selectivity of etherlfication reactions of diols and esterification reactions of diacids by alkyl halides under phase-transfer catalysis has shown that under such conditions, selectivity of monoetherification increases in the order prim < sec < tert diols, though overall yield of monoether decreases from sec to tert diols. Monoesterification of diacids was accomplished with a high degree of selectivity. Optimal extraction of diols and diacids was found to correspond in general to chain lengths of around 5 carbons. This could mean that the complex formed between the catalyst and the anion to react is stabilized for certain carbon lengths by inner solvation in virtue of its spatial conformation.