Catalysis of Trans-esterification Reactions in Model Ester Mixtures

Abstract

Model trans-esterification reaction of n-butylbenzoate with phenyl-p-chlorobenzoate in the molar ratio
of 20:1 has been studied. In order to evaluate catalysts based on lanthanide system the activity of nyodymium compounds – neodymium acetate, neodymium acetylacetonate and nitrate complex with benzo-12-crown-4 (neodymium nitrate coronate) – has been studied in the model trans-esterification reaction of n-butylbenzoate with phenyl-pchlorobenzoate. The effect of the electronic structure of the metal on the catalytic activity of the coronates of lanthanum, cerium, praseodymium, neodymium, samarium, terbium and erbium nitrates has been studied. In order to estimate the optimum concentration of the catalysts, a study of the dependence of the transesterification reaction on concentration of neodymium nitrate coronate was carried out. An asymptotic nature of the concentration dependence on the catalytic activity of lanthanide compounds has been observed. In order to look for new classes of inhibitors of trans-esterefication reaction, the model trans-esterificatiom reaction of n-butylbenzoate with phenyl-p-chlorbenzoate has been studied in the presence of some carborane derivatives: cesium salts of bis-1,2-(dicarbollyl) complexes of iron, cobalt and nickel(3+) and bis-1,2(dicarbollyl) nickel(4+) [(C₂B₉H₁₁)₂Me]. Some of these compounds were found to be effective inhibitors. The dependence of the constant rate of the model trans-esterification reaction of n-butylbenzoate with phenyl-p-chlorobenzoate on the concentration of cerium salt of bis-1,2-(dicarbollyl) complex of nickel has been studied to determine the optimum concentration of inhibitors. The influence of the ester chemical structure on the activity of ester groups in the trans-esterification activity has been determined in the reaction of di-n-butylterephthalate with different p-substituted derivatives of phenylbenzoate (phenyl-p-methoxybenzoate, phenyl-p-methylbenzoate, phenylbenzoate, phenyl- pchlorobenzoate, phenyl-p-nitrobenzoate, p-methoxyphenylbenzoate, p-methylphenylbenzoate, p-chlorophenylbenzoate, p-nitrophenylbenzoate, n-butylbenzoate, di-n-butylterephthalate) in presence of the samarium nitrate coronate.