THE CATALYSTS IMPACT ON THE TRI- AND DIETHANOLAMINE AND ETHYL OLEATE INTERACTION

Abstract

Alkanolamides and ester amines are raw materials for manufacturing surfactants, detergents and cosmetics, pharmaceuticals, and dyes. We investigated the regularities of the interaction between ethyl oleate and a mixture of tri- and diethanolamines (diethanolamine content was 21 wt.%) in the presence of Brønsted and Lewis catalysts. The cation exchange resin KU-2-8, anion exchange resin AB-17-8, potassium hydroxide, nickel oxalate, cation exchange resin KU-2-8 with immobilized Ni2+ ions, cation exchange resin KU-2-8 with immobilized Ni2+ ions treated with a 0.1 M alkali solution within 1 hour, and tin (II) p-toluenesulfonate were used as catalysts. The reaction was carried out in non-stationary conditions with the formed ethanol distillation from the reaction mixture to shift the transesterification reaction equilibrium. It was established that the studied catalysts, with a few exceptions, are characterized by a relatively low rate of reagent conversion. It is shown that the effectiveness of cation exchange resin KU-2-8 in the H-form depends significantly on the temperature and, to a greater extent, on the ethyl oleate and tri- and diethanolamines molar ratio. The study of the reagent ratio influence made it possible to assume that mass transfer processes significantly affect the parameters of ethyl oleate and ethanolamines interaction. It is shown that, under the same conditions, catalytic activity similar to cation exchange resin KU-2-8 is exhibited by anion exchange resin AB-17-8 and tin (II) p-toluenesulfonate. Modifying cation exchange resin KU-2-8 by immobilized nickel ions improves its catalytic properties, and subsequent treatment of the obtained catalyst with an alkali solution even slightly reduces the conversion of ethyl oleate. It was established that nickel oxalate exhibits the highest activity as a catalyst for the reaction between ethyl oleate and tri- and diethanolamines. This effect can be explained by the high electron-accepting properties of the oxalate anion, which reduces the electron density of the Ni2+ cation. As a result, in the presence of this catalyst, the ester conversion is 21.9%. The obtained results made it possible to conclude the potential prospects of using cation exchange resin KU-2-8 in H-form and nickel oxalate as catalysts for ethyl oleate and tri- and diethanolamines interaction.