The assessment of sustainability indicators for triglycerides transesterification with alcohols catalyzed by ion exchange resins

Abstract

The research was aimed at determining the dependences of sustainability indicators on the parameters of the sunflower oil transesterification with ethyl, propyl, and butyl alcohol catalyzed by anion exchange resin AV-17-8 with OH– ions or cation exchange resin KU-2-8 with H+ or immobilized Zn2+, Sn2+, Ni2+, Co2+, and Cu2+ ions. Such sustainability indicators as the E-factor, atomic efficiency, mass intensity and mass productivity, reaction mass efficiency, stoichiometric factor, etc., have been determined. We established that sustainability indicators of transesterification catalyzed by ion exchange resins depend on the yield of higher fatty acid esters that can be achieved by immobilized metal ions. The unreacted alcohol regeneration significantly reduces the E-factor value and increases the reaction mass efficiency. During the sunflower oil ethanolysis, the minimum E-factor value is achieved at the ethyl alcohol:triglyceride molar ratio corresponding to the maximum yield of higher fatty acid esters. The reaction mass efficiency calculated without considering the unreacted alcohol regeneration is one of the criteria for determining its regeneration expediency. The sustainability indicators are the additional criteria for selecting optimal conditions of the sunflower oil transesterification with aliphatic alcohols catalyzed by ion exchange resins. The calculated sustainability indicators indicate that the investigated ion exchange resins as heterogeneous transesterification catalysts provide a high yield of higher fatty acid esters. Using the researched catalysts ensures a low E-factor, making the process environmentally friendly.