Abstract: By the method of electrical conductance, the hydrolysis rate constants(k) of a series of fatty acid esters have been measured in different contents of ethanol solution, and some correlative analyses have been done about the relationship among the molecular structure of a series of fatty acid esters, the conditions of hydrolysis and hydrolysis rate constants(k). A good linear relationship among the hydrolysis rate constants(k), the polarizability effect indices(PEI) of alkyl group R and dielectric constant (ε) is deduced and this behavior can be expressed as lgk=a+blgPEI(R)+clgε. Simultaneously, how the gum acacia affects the hydrolysis rate constants(k) of fatty acid esters in 38.6%(V/V) ethanol solution, and the combination behavior between gum acacia and fatty acid esters have been found. And the way to determine the combination costants(A) between them quantitatively is also found. In addition, the validated quantitative mathematic expression between hydrolysis rate constants(k) of ester and the concentration of gum acacia (M): k=k′/(1+AM) is verified. The result shows that the gum acacia can inhibit the hydrolysis reaction of fatty acid ester.

Key words:  , fatty acid esters； polarizability effect index； dielectric constant； gum acacia； combination constants；