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 ...